WorldWideScience

Sample records for significantly affected weed

  1. Population dynamics of weeds in oil palm (Elaeis guineensis Jacq.) circle weeding area affected by herbicide application

    Science.gov (United States)

    Sidik, S.; Purba, E.; Yakub, E. N.

    2018-02-01

    Weed problems in oil palm field were mainly overcomed by herbicide application. The application certain herbicides may lead to rapid population dynamic of certain species due to their different response to herbicides. Some species may less susceptible to certain herbicide whereas other species more susceptible. The objective of this study was to determine the population dynamic of weed species in circle weeding of oil palm in Serdang Bedagai, North Sumatra. Six treatments using glyphosate singly and mixture compared with manual weeding were evaluated for weed control. The treatments were arranged in a randomized block design with four replicates. Each treatment consisted of four circle weedings. The results showed that glyphosate 720 g a.i/ha + indaziflam 50 g a.i/hareduced seedbank and regrowth of weeds. Up to 12 weeks after application glyphosate 720 g a.i/ha + indaziflam 50 g a.i/ha is 29.46% total weeds dry weight compared to manual weeding. The effect of herbicide application on changes on the weed composition and weed seedbank are affected by the characteristic of herbicides and weed response to herbicide application.

  2. Ecological Weed Management by Cover Cropping: Effect on Winter Weeds and Summer Weeds Establishment in Potato

    Directory of Open Access Journals (Sweden)

    M Ghaffari

    2012-07-01

    Full Text Available Now a day winter cover crops planting has been attended to reduce herbicide application. An experiment was carried out at the Research Farm of Agriculture Faculty, Bu- Ali Sina, University, in 2009. The experiment was a randomized complete block design with three replications. The trial included of five treatments consists of no cover crop, rye, winter oilseed rape, barley and triticale. The results showed that winter cereals were produced more biomass than winter oilseed rape. living mulch of rye, barley, oilseed rape and triticale reduced winter weeds biomass 89, 86, 82 and 70 percent respectively, in compare to control. Cover crop treatments showed significant different weeds control of potato at 3 time (15, 45 and 75 DAPG compare to control treatment. Residues mixed to soil of oilseed rape and rye had the most inhibition affects on summer weeds. These treatments, average weeds biomass decreased 61 and 57 percent respectively, in compare to control. Oilseed rape and rye in compare to control reduced weeds density in potato 36 and 35 percent, respectively. Significant negation correlations of weeds plant population, weeds dry matter with average tuber weight and potato yield. The treatments, oilseed rape and rye in compare to control increased tuber yield of potato 54 and 50 percent, respectively. These treatments, the average tuber weight increased 74 and 38 percent in compare with control, respectively.

  3. Weeds in Organic Fertility-Building Leys: Aspects of Species Richness and Weed Management

    Directory of Open Access Journals (Sweden)

    Thomas F. Döring

    2017-02-01

    Full Text Available Legume-based leys (perennial sod crops are an important component of fertility management in organic rotations in many parts of Europe. Despite their importance, however, relatively little is known about how these leys affect weed communities or how the specific composition of leys may contribute to weed management. To determine whether the choice of plant species in the ley affects weeds, we conducted replicated field trials at six locations in the UK over 24 months, measuring weed cover and biomass in plots sown with monocultures of 12 legume and 4 grass species, and in plots sown with a mixture of 10 legume species and 4 grass species. Additionally, we monitored weed communities in leys on 21 organic farms across the UK either sown with a mixture of the project species or the farmers’ own species mix. In total, 63 weed species were found on the farms, with the annuals Stellaria media, Sonchus arvensis, and Veronica persica being the most frequent species in the first year after establishment of the ley, while Stellaria media and the two perennials Ranunculus repens and Taraxacum officinale dominated the weed spectrum in the second year. Our study shows that organic leys constitute an important element of farm biodiversity. In both replicated and on-farm trials, weed cover and species richness were significantly lower in the second year than in the first, owing to lower presence of annual weeds in year two. In monocultures, meadow pea (Lathyrus pratensis was a poor competitor against weeds, and a significant increase in the proportion of weed biomass was observed over time, due to poor recovery of meadow pea after mowing. For red clover (Trifolium pratense, we observed the lowest proportion of weed biomass in total biomass among the tested legume species. Crop biomass and weed biomass were negatively correlated across species. Residuals from the linear regression between crop biomass and weed biomass indicated that at similar levels of crop

  4. Tillage and residue burning affects weed populations and seed banks.

    Science.gov (United States)

    Narwal, S; Sindel, B M; Jessop, R S

    2006-01-01

    An integrated weed management approach requires alternative management practices to herbicide use such as tillage, crop rotations and cultural controls to reduce soil weed seed banks. The objective of this study was to examine the value of different tillage practices and stubble burning to exhaust the seed bank of common weeds from the northern grain region of Australia. Five tillage and burning treatments were incorporated in a field experiment, at Armidale (30 degrees 30'S, 151 degrees 40'E), New South Wales, Australia in July 2004 in a randomized block design replicated four times. The trial was continued and treatments repeated in July 2005 with all the mature plants from the first year being allowed to shed seed in their respective treatment plots. The treatments were (i) no tillage (NT), (ii) chisel ploughing (CP), (iii) mould board ploughing (MBP), (iv) wheat straw burning with no tillage (SBNT) and (v) wheat straw burning with chisel ploughing (SBC). Soil samples were collected before applying treatments and before the weeds flowered to establish the seed bank status of the various weeds in the soil. Wheat was sown after the tillage treatments. Burning treatments were only initiated in the second year, one month prior to tillage treatments. The major weeds present in the seed bank before initiating the trial were Polygonum aviculare, Sonchus oleraceus and Avena fatua. Tillage promoted the germination of other weeds like Hibiscus trionum, Medicago sativa, Vicia sp. and Phalaris paradoxa later in the season in 2004 and Convolvulus erubescens emerged as a new weed in 2005. The MBP treatment in 2004 reduced the weed biomass to a significantly lower level of 55 g/m2 than the other treatments of CP (118 g/m2) and NT plots (196 g/m2) (P < 0.05). However, in 2005 SBC and MBP treatments were similar in reducing the weed biomass. In 2004, the grain yield trend of wheat was significantly different between CP and NT, and MBP and NT (P < 0.05) with maximum yield of 5898

  5. Quantifying Efficacy and Limits of Unmanned Aerial Vehicle (UAV Technology for Weed Seedling Detection as Affected by Sensor Resolution

    Directory of Open Access Journals (Sweden)

    José M. Peña

    2015-03-01

    Full Text Available In order to optimize the application of herbicides in weed-crop systems, accurate and timely weed maps of the crop-field are required. In this context, this investigation quantified the efficacy and limitations of remote images collected with an unmanned aerial vehicle (UAV for early detection of weed seedlings. The ability to discriminate weeds was significantly affected by the imagery spectral (type of camera, spatial (flight altitude and temporal (the date of the study resolutions. The colour-infrared images captured at 40 m and 50 days after sowing (date 2, when plants had 5–6 true leaves, had the highest weed detection accuracy (up to 91%. At this flight altitude, the images captured before date 2 had slightly better results than the images captured later. However, this trend changed in the visible-light images captured at 60 m and higher, which had notably better results on date 3 (57 days after sowing because of the larger size of the weed plants. Our results showed the requirements on spectral and spatial resolutions needed to generate a suitable weed map early in the growing season, as well as the best moment for the UAV image acquisition, with the ultimate objective of applying site-specific weed management operations.

  6. Quantifying efficacy and limits of unmanned aerial vehicle (UAV) technology for weed seedling detection as affected by sensor resolution.

    Science.gov (United States)

    Peña, José M; Torres-Sánchez, Jorge; Serrano-Pérez, Angélica; de Castro, Ana I; López-Granados, Francisca

    2015-03-06

    In order to optimize the application of herbicides in weed-crop systems, accurate and timely weed maps of the crop-field are required. In this context, this investigation quantified the efficacy and limitations of remote images collected with an unmanned aerial vehicle (UAV) for early detection of weed seedlings. The ability to discriminate weeds was significantly affected by the imagery spectral (type of camera), spatial (flight altitude) and temporal (the date of the study) resolutions. The colour-infrared images captured at 40 m and 50 days after sowing (date 2), when plants had 5-6 true leaves, had the highest weed detection accuracy (up to 91%). At this flight altitude, the images captured before date 2 had slightly better results than the images captured later. However, this trend changed in the visible-light images captured at 60 m and higher, which had notably better results on date 3 (57 days after sowing) because of the larger size of the weed plants. Our results showed the requirements on spectral and spatial resolutions needed to generate a suitable weed map early in the growing season, as well as the best moment for the UAV image acquisition, with the ultimate objective of applying site-specific weed management operations.

  7. Dry Bean Morpho-Physiological Responses to Gradual Weed Biomass Accumulation

    Directory of Open Access Journals (Sweden)

    Hossein GHAMARI

    2013-02-01

    Full Text Available Field study was carried out in 2011 in west of Iran to assess responses of dry bean (Phaseolus vulgaris L. morpho-physiological traits to gradual weed biomass accumulation. The treatments consisted of two different periods of weed interference, which weeds either infested the plots or removed for an increasing duration of time (0, 10, 20, 30, 40, 50 days after crop emergence. Relative dominance and relative importance of weed species fluctuated over the crop cycle. As the duration of weed interference was increased, a declining trend of crop growth rate (CGR was observed. When weeds were allowed to compete with crop throughout the crop cycle, maximum value of CGR was decreased from 25.57 g m-2 days in full season weed free treatment to 16.78 g m-2 days in full season weed infested treatment. Effect of treatments on leaf area index (LAI was significant. Weed removal increased LAI but it could not significantly affect this trait, at the early of growing season. Weed interference caused a significant reduction on number of branches. The minimum number of branches was registered in full season weed infested treatment (2.58 branches per plant, while the maximum one was observed in the full season weed free treatment (4.25 branches per plant. Weed competition severely reduced crop yield. At 10 and 20 days after crop emergence, weed infestation could not significantly affect the yield. A negative relationship between weeds’ dry matter accumulation and LAI as well as number of branches was observed which signify the vulnerability of these morpho-physiological traits to weed competition.

  8. INFLUENCE OF CROPPING SYSTEM AND WEED MANAGEMENT PRACTICE ON EMERGENCE, GROWTH OF WEEDS, YIELD OF MAIZE (Zea mays L. AND COWPEA (Vigna unguiculata L.

    Directory of Open Access Journals (Sweden)

    Felix Ogar Takim

    2014-06-01

    Full Text Available The effects of cropping system and weed management practice on weed seedling emergence, weed biomass production and yield of maize and cowpea were examined at Ilorin, in the southern Guinea savanna (9°29' N, 4°35' E and 307 m ASL of Nigeria. Weed emergence occurred throughout the 3-15 weeks after planting (WAP. Forty-three weed species belonging to 38 genera within 20 families were encountered. Fimbristylis littoralis Gaudet, Tridax procumbens L and Eleusine indica Gaertn were the most prevalent weed species. Cropping system and weed management practice significantly affected weed emergence. Significantly (p≤0.05 lower number of weeds emerged in the intercropped and herbicide treated plots while higher weed densities and weed biomass were recorded in the uncropped and unweeded control plots than in the other plots. While aggregate crop yields were significantly higher in the intercropped than in the sole plots, component crop yields were higher under the sole cropping than in the intercrop. The implication of the results on weed management is discussed.

  9. 1-14 Effect of Plant Spacing and Weeding Frequency on Weed ...

    African Journals Online (AJOL)

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    2College of Agriculture and Environmental Sciences, Haramaya University, ... pod, hundred seed weight, grain yield, aboveground dry biomass, and ... an infestation by weeds and the performance of crop ... frequencies affect weed management in common bean .... including broad-leaved, sedge and grass weeds (Table.

  10. SHIFTING WEED COMPOSITIONS AND BIOMASS PRODUCTION IN SWEET CORN FIELD TREATED WITH ORGANIC COMPOSTS AND CHEMICAL WEED CONTROLS

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    Marulak Simarmata

    2015-10-01

    Full Text Available The objectives of the research were to study the shift of weed compositions in sweet corn field treated with organic compost and chemical weed controls and to compare the effect of treatment combinations on weed growth, weed biomass and sweet corn biomass. The research was conducted in Bengkulu, Indonesia, from April to July 2014. Results showed that the number of weed species decreased after the trials from 14 to 13. There was a shift in weed compositions because 5 species of weeds did not emerge after the trials, but 4 new species were found. Chemical weed control used a herbiside mixture of atrazine and mesotrione applied during postemergence was the most effective method to control weeds, which was observed on decreased weed emergence and weed biomass down to 22.33 and 25.00 percent of control, respectively. Subsequently, biomass production of sweet corn increased up to 195.64 percent at the same trials. Biomass of weeds and sweet corn were also affected by the organic composts. Weed biomass was inhibited by treatment of composted empty fruith bunches of oil palm, whereas significantly increased of sweet corn biomass were observed in the plots of organic manure.

  11. Weeds and Wildlife: Perceptions and Practices of Weed Managers

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    Emma H Carlos

    2014-01-01

    Full Text Available Negative impacts of invasive plants or weeds on biodiversity have been well established yet their role in providing key habitats and resources for wildlife has been little understood. Weed removal thus has the potential to adversely affect wildlife but whether this is considered during weed management is poorly known. To determine the extent of this knowledge, we examined the perceptions of weed managers regarding wildlife and weed management in Victoria, Australia. We surveyed 81 weed managers of varying levels of experience from different types of organisations, including state and local government, community groups and private companies. We found 90% of managers had observed wildlife-weed interactions and that most (70% adjusted management programmes to accommodate wildlife. Despite this, few (19% had adopted the recommended practice of combining gradual weed removal with re-vegetation. While management programmes included monitoring of native vegetation, consideration of wildlife monitoring in weed management was rare. This highlights the need for management to better understand and respond to wildlife-weed relationships. If the improvement of wildlife habitat is included in the objectives of weed programmes, as it should be, then wildlife should also be incorporated in project monitoring. This would lead to a greater understanding of the role weeds and their management have in each situation and, ultimately, more informed decision making.

  12. Sowing time affects the abundance of pests and weeds in winter rye

    Directory of Open Access Journals (Sweden)

    E. HUUSELA-VEISTOLA

    2008-12-01

    Full Text Available Selection of an appropriate sowing time for some winter rye (Secale cereale cultivars could reduce the need for crop protection measures. In this study the occurrence and status of pests and weeds in relation to sowing time and growth habit of winter rye was studied in southern Finland. This was done using three sowing times and four rye varieties in field trials conducted at three locations in 1999–2001. The early sown rye was severely affected by pests (Oscinella frit, Mayetiola destructor and weeds, whereas postponing sowing for two weeks after the recommended sowing time in late August resulted in considerably less damage and the optimal establishment of crop stands. The German hybrid varieties Picasso and Esprit produced more tillers m-2 in autumn than the Finnish varieties Anna and Bor 7068. However, the number of pests and weeds did not differ among rye varieties. Late sowing of rye should be considered to minimize the need for plant protection. If rye is sown at the recommended time it may still require insecticide treatments promptly in the autumn whereas herbicide treatment need not be determined until spring, after recording the winter mortality of weeds.;

  13. Weeds Cause Losses in Field Crops through Allelopathy

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    Ali ZOHAIB

    2016-03-01

    Full Text Available A large number of weeds are known to be associated with crops and causing economic losses. Weeds interfere with crops through competition and allelopathy. They produce secondary metabolites known as allelochemicals, which belong to numerous chemical classes such as phenolics, alkaloids, fatty acids, indoles, terpens etc. However, phenolics are the predominant class of allelochemicals. The allelochemicals release from weed plants takes place through leaf leachates, decomposition of plant residues, volatilization and root exudates. Weeds leave huge quantities of their residues in field and affect the associated, as well as succeeding crops, in various cropping systems. Liberation of allelochemicals from weeds affects the germination, stand establishment, growth, yield and physiology of crop plants. They cause substantial reduction in germination and growth of the crop plants by altering various physiological processes such as enzyme activity, protein synthesis, photosynthesis, respiration, cell division and enlargement, which ultimately leads to a significant reduction in crop yield. In crux, allelopathic weeds represent a potential threat for crop plants and cause economic losses.

  14. Do Tillage Methods Affect Germination and Species Similarity of Soil Weed Seeds Bank?

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    Shahgholi Hassan

    2015-12-01

    Full Text Available Cultural practices such as tillage used for crop production influence the composition of the weed seed bank in the soil. In order to investigate the effects of different tillage methods on seed bank properties, species diversity and similarity, two laboratory and greenhouse experiments were carried out as randomized complete block design with four replications in 2011. Treatments included: once tillage per year (T1, twice tillage per year (T2, more than twice tillage (T3 and no tillage (T4. Laboratory results showed that the T3 and T4 treatments had the highest and the lowest observed seeds numbers, respectively. Between the laboratory observed weed seeds, the maximum weed seed numbers were Echinochloa crus-galli and Amaranthus retroflexus in the T3 treatment, while Chenopodium album, Polygonum aviculare and Cuscuta campestris had the highest seed numbers in the T2 treatment. At the greenhouse study, Chenopodium album, Amaranthus retroflexus and Hordeum morinum in the T2 treatment were dominant species. The highest diversity was observed in the T2 treatment, and Chenopodium album and Echinochloa crus-galli were dominant species in the T2 and T3 treatments. Maximum species similarity index was achieved from the T1 and T3 treatments. Thereby this study concluded that increasing of tillage number could affect the similarity index of weed seeds and subsequently alters the weed community composition.

  15. Weed flora, yield losses and weed control in cotton crop

    OpenAIRE

    Jabran, Khawar

    2016-01-01

    Cotton (Gossypium spp.) is the most important fiber crop of world and provides fiber, oil, and animals meals. Weeds interfere with the growth activities of cotton plants and compete with it for resources. All kinds of weeds (grasses, sedges, and broadleaves) have been noted to infest cotton crop. Weeds can cause more than 30% decrease in cotton productivity. Several methods are available for weed control in cotton. Cultural control carries significance for weed control up to a certain extent....

  16. Factors affecting the population density of weeds and yield loss of them in wheat: a case study in Golestan province – Bandargaz

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    Mohamad Zaman Nekahi

    2016-05-01

    Full Text Available To investigate the factors affecting the population density of weeds and yield loss of them in wheat, a non systematic survey experiment was conducted in 45 fields in the township of Bandar-gaz (Sarmahaleh village in 2012. Sampling of wheat and weeds were taken in two stages (Heading and Harvest maturity by randomized to the five points of each field using quadrate size 1m*1m. In this study all information about crop management including Land area , farmers experience , the seed bed preparation, sowing date , cultivar and site preparation of them, sowing ways , seed rate , weeds control ways , kind , amount and time of herbicide , fungicide use and wheat harvest time were collected during a growing season by preparing questionnaire and complete them with farmers. At the end of the growing season, the actual yield harvested by farmers’ ‬ recorded. Among the various parameters, Wheat plant and raceme density, farmer experience, Kind of variety and use of Tapic+Geranestar herbicide had significant effects on weed population. With increased wheat plant density, weed density decreased. Also there was less weed density in field of high experience farmer. Weed density was lesser in N8118 variety than N8019 variety and not use Tapic+granestar herbicide due to increased of weeds density. Among weed different species, Avena sp, Phalaris minor and Sinapis arvense had highest negative effect on wheat yield. Model study showed if wheat plant density was optimum and there were weeds, yield will be 2713kg/ha and if weeds remove yield will increase to 2877kg/ha (yield gap equal164kg/ha. Amaong weed, Phalaris minor (12 plant per m-2, Sinapis arvensis (3plant per m-2 and Avena sp (2 plant per m-2 with 65, 18 and 17% yield loss respectively, were the strongest competitor with wheat.

  17. Effects of different crop associations and fertilizer types on weed ...

    African Journals Online (AJOL)

    Experiments were conducted at the Teaching and Research Farm of the University of Ibadan in 1998/1999 and 1999/2000 cropping seasons to determine the effects of different crop associations and fertilizer types on the weed biomass. The results showed that crop associations did not significantly affect weed density and ...

  18. WEED CONTROL EFFECTS ON SOIL CHEMICAL CHARACTERISTICS

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    Paulo Sérgio Lima e Silva

    2008-01-01

    Full Text Available The weed control procedures are known to affect the soil physical attributes and the nutrient amount taken up by weed roots. This work hypothesis is that weed control methods might also affect soil chemical attributes. Four experiments were carried out, three with maize (E-1, E-2 and E-3 and one with cotton (E-4, in randomized complete blocks design arranged in split-plots, with five replications. In E-1 experiment, the plots consisted of two weed control treatments: no-weed control and weed shovel-digging at 20 and 40 days after sowing; and the subplots consisted of six maize cultivars. In the three other experiments, the plots consisted of plant cultivars: four maize cultivars (E-2 and E-3 and four cotton cultivars (E-4. And, the subplots consisted of three weed control treatments: (1 no-weed control; (2 weed shovel-digging at 20 and 40 days after sowing; and (3 intercropping with cowpea (E-2 or Gliricidia sepium (Jacq. Walp. (E-3 and E-4. In all experiments, after harvest, eight soil samples were collected from each subplot (0-20 cm depth and composed in one sample. Soil chemical analysis results indicated that the weed control by shovel-digging or intercropping may increase or decrease some soil element concentrations and the alterations depend on the element and experiment considered. In E-2, the weed shovel-dug plots showed intermediate soil pH, lower S (sum of bases values and higher soil P concentrations than the other plots. In E-4, soil K and Na concentrations in plots without weed control did not differ from plots with intercropping, and in both, K and Na values were higher than in weed shovel-dug plots. Maize and cotton cultivars did not affect soil chemical characteristics.

  19. Effect of Cultural Practices in Night on Weed Density and Weed Dry Matter

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    M.H Rashed Mohasel

    2011-01-01

    Full Text Available Abstract In order to evaluate the response of weed seeds to light, two experiments, at two different locations were conducted at Ferdowsi university of Mashhad in 2009. At the first experiment, field was ploughed in day and night. Weed density was evaluated 70 d after plough, with 1×1 quadrate. At the second experiment, at night treatment, ploughing, potato planting and weeding with cultivator were done at night. Weed sampling was done twice at 43 and 130 days after planting with 1×1 quadrate and weeds were identified and counted. Result showed pigweed (Amaranthus retroflexus L., sowthistle (Sonchus oleraceus L., crabgrass (Digitaria sanguinalis (L. scop, jimsonweed (Datura stramonium L. and mallow (Hibiscus trionum L. did not observed at night plough, in contrast, night plough has no significance influence on common lambsquarters (Chenopodium album L., and black nightshade (Solanum nigrum L.. Only common lambsquarters had similar appearance in two treatments, indicating insusceptibility of this weed to time of plough. Interestingly, at the second experiment, result was very similar. Potato yield was higher at night treatment, but not significant. This research showed that some cultural practice like plough, planting and weeding with cultivator in night can reduce weed density and weed dry matter. Keywords: Germination, Time of plough, Sustainable weeds management, Light

  20. Adapting weed management in rice to changing climates

    NARCIS (Netherlands)

    Rodenburg, J.; Meinke, H.B.

    2011-01-01

    This paper provides some of the scientific background on how projected environmental conditions could affect weeds and weed management in rice in Africa. Elevated CO2 levels may have positive effects on rice competitiveness with C4 weeds, but these are generally outnumbered by C3 species in weed

  1. Planting pattern and weed control method influence on yield production of corn (Zea mays L.)

    Science.gov (United States)

    Purba, E.; Nasution, D. P.

    2018-02-01

    Field experiment was carried out to evaluate the influence of planting patterns and weed control methods on the growth and yield of corn. The effect of the planting pattern and weed control method was studied in a split plot design. The main plots were that of planting pattern single row (25cm x 60cm), double row (25cm x 25cm x 60cm) and triangle row ( 25cm x 25cm x 25cm). Subplot was that of weed control method consisted five methods namely weed free throughout the growing season, hand weeding, sprayed with glyphosate, sprayed with paraquat, and no weeding.. Result showed that both planting pattern and weed control method did not affect the growth of corn. However, planting pattern and weed control method significantly affected yield production. Yield resulted from double row and triangle planting pattern was 14% and 41% higher, consecutively, than that of single row pattern. The triangle planting pattern combined with any weed control method produced the highest yield production of corn.

  2. Weed Interference Effects on Leaves, Internode and Harvest Index of Dry Bean (Phaseolus vulgaris L.

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    Hossein GHAMARI

    2015-03-01

    Full Text Available The development of appropriate weed management strategies and efficient use of herbicides relies upon understanding weed-crop interactions. A field study was carried out to assess the effect of weed interference on leaves, internode and harvest index of dry bean (Phaseolus vulgaris L.. The experiment was established under a randomized complete block design with two types of weed interference treatments: plots with weeds and plots without weeds at different time intervals (0, 10, 20, 30, 40 and 50 days after crop emergence. The sigmoid Boltzmann model was used to quantify the crop traits as influenced by weed interference. Prolonged delays in weed removal reduced gradually the number of leaves of the crop. Weed interference decreased dry weight of leaves as well, so that the lowest value of it (33.49 g plant-1 was observed in full season during weed-infested treatment. Infestation of weeds affected the length of the crop internodes. While the weed interference duration increased, the length of the internodes decreased. Harvest index was also sensitive to weed competition. As the crop was kept weed-infested from the emergence for increasing periods of time, harvest index decreased to a value of 28.01%. A significant negative correlation between total biomass of weeds and dry bean traits (number of leaves, leaves dry weight, internode length and harvest index was observed. Therefore, weeds are able to adversely affect dry bean growth through constraining environmental resources and impairing leaves as the photosynthetic areas.

  3. Weed Diversity Affects Soybean and Maize Yield in a Long Term Experiment in Michigan, USA.

    Science.gov (United States)

    Ferrero, Rosana; Lima, Mauricio; Davis, Adam S; Gonzalez-Andujar, Jose L

    2017-01-01

    Managing production environments in ways that promote weed community diversity may enhance both crop production and the development of a more sustainable agriculture. This study analyzed data of productivity of maize (corn) and soybean in plots in the Main Cropping System Experiment (MCSE) at the W. K. Kellogg Biological Station Long-Term Ecological Research (KBS-LTER) in Michigan, USA, from 1996 to 2011. We used models derived from population ecology to explore how weed diversity, temperature, and precipitation interact with crop yields. Using three types of models that considered internal and external (climate and weeds) factors, with additive or non-linear variants, we found that changes in weed diversity were associated with changes in rates of crop yield increase over time for both maize and soybeans. The intrinsic capacity for soybean yield increase in response to the environment was greater under more diverse weed communities. Soybean production risks were greatest in the least weed diverse systems, in which each weed species lost was associated with progressively greater crop yield losses. Managing for weed community diversity, while suppressing dominant, highly competitive weeds, may be a helpful strategy for supporting long term increases in soybean productivity. In maize, there was a negative and non-additive response of yields to the interaction between weed diversity and minimum air temperatures. When cold temperatures constrained potential maize productivity through limited resources, negative interactions with weed diversity became more pronounced. We suggest that: (1) maize was less competitive in cold years allowing higher weed diversity and the dominance of some weed species; or (2) that cold years resulted in increased weed richness and prevalence of competitive weeds, thus reducing crop yields. Therefore, we propose to control dominant weed species especially in the years of low yield and extreme minimum temperatures to improve maize yields

  4. Robotic weeding and automated weed measurements

    DEFF Research Database (Denmark)

    Christensen, S.; Søgaard, H.T.; Jørgensen, R.N.

    2003-01-01

    The goal of decreasing herbicide usage has so far focused on reducing the herbicide dosage or replacing chemical weed control by hoeing and harrowing. The conventional weed control strategy is to apply the same dose of herbicide or the same intensity of hoeing and harrowing in the whole field. Th...... the state-of-the-art of automated weed measurement methods and the research projects concerning autonomous platform and information system for crop and weed monitoring and robotic weeding....

  5. Weeds in a Changing Climate: Vulnerabilities, Consequences, and Implications for Future Weed Management.

    Science.gov (United States)

    Ramesh, Kulasekaran; Matloob, Amar; Aslam, Farhena; Florentine, Singarayer K; Chauhan, Bhagirath S

    2017-01-01

    Whilst it is agreed that climate change will impact on the long-term interactions between crops and weeds, the results of this impact are far from clear. We suggest that a thorough understanding of weed dominance and weed interactions, depending on crop and weed ecosystems and crop sequences in the ecosystem, will be the key determining factor for successful weed management. Indeed, we claim that recent changes observed throughout the world within the weed spectrum in different cropping systems which were ostensibly related to climate change, warrant a deeper examination of weed vulnerabilities before a full understanding is reached. For example, the uncontrolled establishment of weeds in crops leads to a mixed population, in terms of C 3 and C 4 pathways, and this poses a considerable level of complexity for weed management. There is a need to include all possible combinations of crops and weeds while studying the impact of climate change on crop-weed competitive interactions, since, from a weed management perspective, C 4 weeds would flourish in the increased temperature scenario and pose serious yield penalties. This is particularly alarming as a majority of the most competitive weeds are C 4 plants. Although CO 2 is considered as a main contributing factor for climate change, a few Australian studies have also predicted differing responses of weed species due to shifts in rainfall patterns. Reduced water availability, due to recurrent and unforeseen droughts, would alter the competitive balance between crops and some weed species, intensifying the crop-weed competition pressure. Although it is recognized that the weed pressure associated with climate change is a significant threat to crop production, either through increased temperatures, rainfall shift, and elevated CO 2 levels, the current knowledge of this effect is very sparse. A few models that have attempted to predict these interactions are discussed in this paper, since these models could play an

  6. Weed control and cover crop management affect mycorrhizal colonization of grapevine roots and arbuscular mycorrhizal fungal spore populations in a California vineyard.

    Science.gov (United States)

    Baumgartner, Kendra; Smith, Richard F; Bettiga, Larry

    2005-03-01

    Arbuscular mycorrhizal (AM) fungi naturally colonize grapevines in California vineyards. Weed control and cover cropping may affect AM fungi directly, through destruction of extraradical hyphae by soil disruption, or indirectly, through effects on populations of mycorrhizal weeds and cover crops. We examined the effects of weed control (cultivation, post-emergence herbicides, pre-emergence herbicides) and cover crops (Secale cereale cv. Merced rye, x Triticosecale cv.Trios 102) on AM fungi in a Central Coast vineyard. Seasonal changes in grapevine mycorrhizal colonization differed among weed control treatments, but did not correspond with seasonal changes in total weed frequency. Differences in grapevine colonization among weed control treatments may be due to differences in mycorrhizal status and/or AM fungal species composition among dominant weed species. Cover crops had no effect on grapevine mycorrhizal colonization, despite higher spring spore populations in cover cropped middles compared to bare middles. Cover crops were mycorrhizal and shared four AM fungal species (Glomus aggregatum, G. etunicatum, G. mosseae, G. scintillans) in common with grapevines. Lack of contact between grapevine roots and cover crop roots may have prevented grapevines from accessing higher spore populations in the middles.

  7. Image-based thresholds for weeds in maize fields

    DEFF Research Database (Denmark)

    Asif, Ali; Streibig, Jens Carl; Christensen, Svend

    2015-01-01

    in some parts of the field and if late germinating weeds do not affect yield, it may not be necessary the spray such places from an economic point of view. Consequently, it makes sense to develop weed control thresholds for patch spraying, based on weed cover early in the growing season. In Danish maize...

  8. Weed control in tomato (lycopersicon esculentum mill.) through mulching and herbicides

    International Nuclear Information System (INIS)

    Bakht, T.; Khan, I.A.

    2014-01-01

    Experiments were conducted at the Agricultural Research Farm of the University of Agriculture, Peshawar during 2012 and 2013 to determine the impact of row spacing and weed management strategies on tomato (Lycopersicon esculantum Mill.). Variety 'Roma' was planted on a plot size of 4.8m x 3m using a randomized complete block (RCB) design in split plot arrangements, having four replications. The experiment comprised of row spacing in main plots and ten treatments in the subplots that included five mulches viz., white polyethylene, black polyethylene, wheat straw, newspaper and saw dust; three herbicide treatments i.e. fenoxaprop-p-ethyl, pendimethalin, s-metolachlor along with a hand weeding treatment and a weedy check. The data were recorded on weed density m-2 at 20 days after treatments, plant height, fruit yield (kg ha-1). All the studied parameters were significantly affected by the row spacing (factor A) and weed management treatments (factor B); however, the interaction effects were non-significant. An increase in weed density was observed with increase in row spacing, having weed density of 3.39, 4.19 and 4.53 weeds m-2 for 40, 60 and 80 row spacing, respectively. The overall weed density m-2 ranged between 3.24 to 4.30 m-2. A maximum plant height of 62.44cm was recorded in weedy check and minimum 53.31cm plant height was observed in hand weeding treatments. As regards the fruit yield, a highest yield of 2.51 t ha-1 was recorded at row spacing of 60 cm (factor A) and the application of poly ethylene black plastic resulted in significantly highest fruit yield (4.04 t ha-1) among factor B treatments. (author)

  9. Chemical weed control in Spinach (Spiniacia oleracea

    Directory of Open Access Journals (Sweden)

    A. Modhej

    2016-03-01

    (Convolvulus arvensis, Common lambsquarters (Chenopodium album, Malva (Malva spp., Chamomile (Anthemis altissima, Purple nutsedge (Cyperus rotundus, canary grass (Phalaris minor, mouse barley (Hordeum morinum and Japan brome (Bromus japonicus, respectively. The results of variance analysis showed that the effects of treatments on the number of broadleaf and weed narrow leaves were significant. Meteribouzin and Pendimethalin herbicides (pre-emergence, had better control on broadleaf weed than other herbicides. Low amounts of herbicides EPTC (5 lit ha-1 and imazethapyr (0.7 lit ha-1 were the least effective broadleaf weed control. Trifluralin herbicide reduced approximately 44% broadleaf weed density compared to control plots without control. The minimum weight of broadleaf weed at all doses studied allocated to herbicides Pendimethalin and Meteribouzin. Most of reducing the number narrow leaves was belonged to Meteribouzin and Pendimethalin herbicides as pre-emergence with doses of 300 g and 3 lit ha-1, respectively. The effect of treatments on petiole length, number of leaves per plant and the spinach fresh yield was significant in 1% probability level. Meteribouzin damage in spinach was 100%. It was reported that the half-life in soil herbicide Meteribouzin is about 30-60 days. It seems spinach a high sensitivity to the herbicide and relatively long survival in the soil that causing damage spinach was perfect, while maximum weed control amounts in all methods of used allocated to this herbicide. Number of leaves per plant trait was that less affected by weed interference. Both components of leaves per plant (r= 69.0** and petiole length (r= 87.0** showed significant positive correlation with the spinach fresh yield. The highest spinach yield was obtained in Trifluralin herbicide after treatments control. The difference between spinach yield in Trifluralin and control treatments was not significant. Conclusion: In general, the results showed that the broad and narrow leaf

  10. Weed management practices affect the diversity and relative abundance of physic nut mites.

    Science.gov (United States)

    Saraiva, Althiéris de Sousa; Sarmento, Renato A; Erasmo, Eduardo A L; Pedro-Neto, Marçal; de Souza, Danival José; Teodoro, Adenir V; Silva, Daniella G

    2015-03-01

    Crop management practices determine weed community, which in turn may influence patterns of diversity and abundance of associated arthropods. This study aimed to evaluate whether local weed management practices influence the diversity and relative abundance of phytophagous and predatory mites, as well as mites with undefined feeding habits--of the families Oribatidae and Acaridae--in a physic nut (Jatropha curcas L.) plantation subjected to (1) within-row herbicide spraying and between-row mowing; (2) within-row herbicide spraying and no between-row mowing; (3) within-row weeding and between-row mowing; (4) within-row weeding and no between-row mowing; and (5) unmanaged (control). The herbicide used was glyphosate. Herbicide treatments resulted in higher diversity and relative abundance of predatory mites and mites with undefined feeding habit on physic nut shrubs. This was probably due to the toxic effects of the herbicide on mites or to removal of weeds. Within-row herbicide spraying combined with between-row mowing was the treatment that most contributed to this effect. Our results show that within-row weeds harbor important species of predatory mites and mites with undefined feeding habit. However, the dynamics of such mites in the system can be changed according to the weed management practice applied. Among the predatory mites of the family Phytoseiidae Amblydromalus sp. was the most abundant, whereas Brevipalpus phoenicis was the most frequent phytophagous mite and an unidentified oribatid species was the most frequent mite with undefined feeding habit.

  11. Performance and Economics of Growing Maize under Organic and Inorganic Fertilization and Weed Management

    International Nuclear Information System (INIS)

    Ali, A.; Khan, M. A.; Jan, A. U.; Jan, D.; Sattar, S.; Saleem, A.; Marwat, K. B.

    2016-01-01

    Weed competition and imbalanced fertilizers are important yield reducing factors in maize. To investigate the impact of weed management and combinations of fertilizers on yield and net income of maize, a field trial was conducted at National Agricultural Research Centre, Islamabad, Pakistan during summer 2014. Randomized complete block design with split-plot arrangement was used with three replications. Four weeds pressures viz. (1) hand weeding at 25 cm on both sides of each row of maize plants, (2) No hand weeding at 25 cm on both sides of maize rows, (3) application of Primextra gold (atrazine plus S-metolachlor) at the rate of 1.44 kg a.i. ha/sup -1/ as pre-emergence and (4) weedy check (control) were assigned to main plots. While different combinations of NPK were assigned to sub plots. Data revealed that dry weed biomass close to maize plants were significantly lower (140.4 kg ha/sup -1/) as compared to weeds 25 cm away from maize plants (153.2 kg ha/sup -1/). However, the application of atrazine plus S-metolachlor showed promising results by decreasing the weed biomass (53.6 kg ha/sup -1/) as compared to 155.6 kg ha/sup -1/ in control. Combination of fertilizers, also significantly affected the weed biomass. As compared to control, all the fertilizers (N, P and K) significantly increased weed biomass. Presence of weeds close to the crop rows, proved more harmful for grain yield of maize. Overall, application of herbicide in combination with NPK showed promising results in term of weed control and grain yield. Net income was higher when herbicide in combination with N, P or NP was used. (author)

  12. Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions.

    Science.gov (United States)

    Johansen, Anders; Nielsen, Henrik B; Hansen, Christian M; Andreasen, Christian; Carlsgart, Josefine; Hauggard-Nielsen, Henrik; Roepstorff, Allan

    2013-04-01

    Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this practice may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seeds of seven species of weeds and non-embryonated eggs of the large roundworm of pigs, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (55°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55°C) was very clear as complete mortality, irrespective of weed species, was reached after less than 2 days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzinckia micrantha still maintained low levels (~1%) of germination ability after 1 week. Chenopodium album was the only weed species which survived 1 week at substantial levels (7%) although after 11 d germination ability was totally lost. Similarly, at 55°C, no Ascaris eggs survived more than 3h of incubation. Incubation at 37°C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking spread of these pests. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Weed infestation of spring barley (Hordeum vulgare L. depending on the cover crop and weed control method

    Directory of Open Access Journals (Sweden)

    Dorota Gawęda

    2014-04-01

    Full Text Available The aim of this 3-year field study was to evaluate the effect of some stubble crops and weed control methods on the species composition, number and air-dry weight of weeds in a spring barley crop grown in short-term monoculture. The study was conducted in the period 2009–2011 at the Uhrusk Experimental Farm, on mixed rendzina soil classified as very good rye soil complex. It included stubble crops which were ploughed under in each year (control treatment without cover crop, white mustard, lacy phacelia, a mixture of legumes – narrow-leaf lupin + field pea and 3 weed control methods used in spring barley crops (mechanical, mechanical and chemical, chemical weed control. Veronica persica was the weed species that occurred in greatest numbers in the spring barley crop sown after stubble crops. All cover crops reduced the numbers of Avena fatua which was the dominant species in the control treatment. Chemical as well as chemical and mechanical weed control significantly reduced the numbers of Avena fatua compared to the treatment where only double harrowing was used for weed control. The stubble crops did not reduce weed infestation of spring barley. Compared to the control treatment, the ploughing-in of white mustard and the mixture of legumes reduced the dry weight of weeds by 49.1 and 22.7%, respectively. Mechanical weed management proved to be less effective in reducing the number and dry weight of weeds compared to the other weed control methods. A significant negative correlation was found between the dry weight of weeds in the spring barley crop and the dry weight of the ploughed-in white mustard cover crop under the conditions of chemical weed control as well as in the case of the mixture of legumes when complete mechanical and chemical weed control was used.

  14. Effects of Intercropping (Canola-Faba Bean on Density and Diversity of Weeds

    Directory of Open Access Journals (Sweden)

    Mohamad Hossain GHARINEH

    2010-03-01

    Full Text Available In order to evaluate the biological effect and interference of crop and weed in canola-faba bean intercropping in comparison with mono culture, an experiment was conducted in randomize completely blocks design with three replication at Ramin Agriculture and Natural Resources, University. In this experiment treatments were different compositions of canola (Brassica napus L. var. haylo and faba bean (local cultivar. Plant densities (0, 20 and 40 plants per m2 for canola and four levels include (0, 20, 40 and 60 plants per m2 for faba bean in accordance with additive form mixed culture system respectively. Weed dry weight was affected by culture system and different levels of plant densities in mixed culture and there were significant difference 1%. Lowest weed dry weight was obtained in 20-60 and 40-60 plants m-2 canola-bean intercropping. In the intercropping parts only two species was observed while in the sole culture more than three species were exist. Results showed that with increasing in bean diversity, weed dry weight declines. According to our results, it is possible to control weed effectively by using intercropping system, but more studied is required. Diversity of weeds had been clearly affected. Results showed that only Beta and Malva species were existed in intercropping comparing to sole cultures that Brassica, Beta, Rumex and Malva were existed.

  15. Integration of row spacing, mulching and herbicides on weed management in tomato

    International Nuclear Information System (INIS)

    Bakht, T.; Khan, I.A.

    2014-01-01

    A field experiment was conducted at the Research Farm of The University of Agriculture, Peshawar during the year 2012 to determine the impact of row spacing and weed management strategies on tomato (Lycopersicon esculentum Mill.). The local variety 'Roma' was sown in a randomized complete block (RCB) design with split plot arrangements, having four replications. The main plots were row spacings while subplots of the experiment comprised of ten treatments including five mulches viz., white and black polyethylene, wheat straw, newspaper and saw dust, three herbicide treatments (fenoxaprop-p-ethyl, pendimethalin and s-metolachlor), hand weeding and a weedy check. The data were recorded on weed density m/sup -2/, fresh and dry weed biomass, number of branches plant-1, and fruit yield (kg ha/sup -1/). All these parameters were significantly affected by row spacing and weed management treatments. Increase in weed population was observed with increasing in row spacing. The competitiveness of tomato with weeds can be enhanced by using black plastic as mulch. In light of the results, the row spacing of 60 cm is the optimum one for tomato plants, as the fruit yields decreased at 40 cm and 80 cm row spacing. (author)

  16. Virus infection of a weed increases vector attraction to and vector fitness on the weed.

    Science.gov (United States)

    Chen, Gong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Fang, Yong; Shi, Xiaobin; Zhang, Youjun

    2013-01-01

    Weeds are important in the ecology of field crops, and when crops are harvested, weeds often become the main hosts for plant viruses and their insect vectors. Few studies, however, have examined the relationships between plant viruses, vectors, and weeds. Here, we investigated how infection of the weed Datura stramonium L. by tomato yellow leaf curl virus (TYLCV) affects the host preference and performance of the TYLCV vector, Bemisia tabaci (Gennadius) Q. The results of a choice experiment indicated that B. tabaci Q preferentially settled and oviposited on TYLCV-infected plants rather than on healthy plants. In addition, B. tabaci Q performed better on TYLCV-infected plants than on healthy plants. These results demonstrate that TYLCV is indirectly mutualistic to B. tabaci Q. The mutually beneficial interaction between TYLCV and B. tabaci Q may help explain the concurrent outbreaks of TYLCV and B. tabaci Q in China.

  17. Effect of Plant Density and Weed Interference on Yield and Yied Components of Grain Sorghum

    Directory of Open Access Journals (Sweden)

    S. Sarani

    2018-01-01

    Full Text Available Introduction Weed control is an essential part of all crop production systems. Weeds reduce yields by competing with crops for water, nutrients, and sunlight. Weeds also directly reduce profits by hindering harvest operations, lowering crop quality, and producing chemicals which are harmful to crop plants. Plant density is an efficient management tool for maximizing grain yield by increasing the capture of solar radiation within the canopy, which can significantly affect development of crop-weed association. The response of yield and yield components to weed competition varies by crop and weeds species and weeds interference duration. The objective of the present study was to evaluate the effect of weed interference periods and plant density on the yield and yield components of sorghum. Materials and Methods In order to study the effect of plant density and weeds interference on weeds traits, yield and yield components of sorghum (Var. Saravan, an experiment was conducted as in factorial based on a randomized complete block design with three replications at the research field of Islamic Azad University, Birjand Branch in South Khorasan province during year of 2013. Experimental treatments consisted of three plant density (10, 20 and 30 plants m-2 and four weeds interference (weed free until end of growth season, interference until 6-8 leaf stage, interference until stage of panicle emergence, interference until end of growth season. Measuring traits included the panicle length, number of panicle per plant, number of panicle per m2, number of seed per panicle, 1000-seed weight, seed yield, biological yield, number and weight of weeds per m2. Weed sampling in each plot have done manually from a square meter and different weed species counted and oven dried at 72 °C for 48 hours. MSTAT-C statistical software used for data analysis and means compared with Duncan multiple range test at 5% probability level. Results and Discussion Results showed that

  18. Evaluation of the Impact of Weed Control Methods on Quantitative and Qualitative Characteristics of Moldavian Balm; A Medicinal Plant

    Directory of Open Access Journals (Sweden)

    Janmohammadi Mohsen

    2016-12-01

    Full Text Available Moldavian balm is an annual herbaceous plant and its lemon-scented leaves contain essential oil. However, weeds adversely affect its growth by release of allelochemicals, and/or direct competition for nutrient, moisture, light and space. Current experiment was conducted to evaluate the different weed control methods including preventive approach (soil pasteurization, mechanical methods (one hand weeding, two hand weeding, and successive hand weeding for weed free condition, and chemical control by synthetic herbicides (haloxyfop-R-methyl and trifluralin. Results revealed that stem diameter, quantity of secondary branches, flower-bearing branches and leaves were significantly affected by weed control treatments; the highest lateral growth was obtained by successive mechanical weed control and two hand weeding method, respectively. This trend was also observed in canopy spread and chlorophyll content. Pre-emergence control by trifluralin considerably accelerated the initiation of flowering in Moldavian balm. However, observation of qualitative traits showed that the highest essential oil content and oil yield was obtained when the plants grew in weed free soil which was pasteurized. Considering the recognized essential oils, the most responsive composition was including Geranial, Geranyl acetate, Neral and Geraniol. The lowest amount of Neral was recorded in postemergence control performed by means of haloxyfop-R-methyl herbicide.

  19. Nitrogen availability in an apple orchard with weed management

    Directory of Open Access Journals (Sweden)

    Gustavo Brunetto

    2018-05-01

    Full Text Available ABSTRACT: Weed management in apple orchards (Malus domestica can affect the leaching of nitrogen (N in soil. The study aimed to evaluate the potential leaching of N forms in soil of an apple orchard with different weed management treatments. The experiment was conducted in an apple orchard implanted in 2008. In October 2011, 80 plants were selected and the following treatments were implemented: no weed management (NM, desiccation of weeds on the tree row with herbicide use (DR and mechanical mowing of weeds on the tree row (MR. Yield was evaluated in the 2011/2012, 2012/2013 and 2013/2014 crop seasons. In May 2012 porous cup lysimeters were installed in the NM, DR and MR treatments. In the solution collected at 0.20m, NH4 +-N and NO3 --N were analyzed sixteen times and mineral N concentration was calculated. The highest concentrations of NO3 --N and mineral N occurred in soil solution with DR, which increases availability of the nutrient to apple trees, but also enhances the potential losses. Weed management and N flow in the solution did not affect apple yield.

  20. Effects of long-term reduced tillage on weed infestation of pea (Pisum sativum L.

    Directory of Open Access Journals (Sweden)

    Andrzej Woźniak

    2014-09-01

    Full Text Available The study evaluated weed infestation of pea (Pisum sativum L. cultivated under conditions of conventional (CT, reduced (RT and herbicide tillage (HT. It demonstrated the highest weed density per m2 in plots with the herbicide (HT and reduced (RT systems and significantly lower weed infestation in plots cultivated in the conventional system (CT. In addition, more weeds occurred at the third leaf stage (13/14 in BBCH scale than at the pod development stage (73/74 BBCH of pea. The highest biomass was produced by weeds in the herbicide system (HT, a lower one – in the reduced system (RT, and the lowest one – in the conventional system (CT. The air-dry weight of weeds depended also on pea development stage. At the pod development stage (73/74 BBCH, the air-dry weight of weeds was significantly higher than at the third leaf stage (13/14 BBCH. The tillage system was also observed to influence the species composition of weeds. This trait was also affected by the period of weed infestation assessment. At the third leaf stage of pea (13/14 BBCH, there occurred 26 weed species, including 24 annual ones. The most abundant species included: Chenopodium album L., Stellaria media (L. Vill., Capsella bursa-pastoris (L. Med., Matricaria inodora L., Thlaspi arvense L., and Fallopia convolvulus (L. A. Löve. At the pod development stage (73/74 BBCH, the pea crop was colonized by 24 weed species, including 3 perennial ones. At this stage the predominant species included: Avena fatua L., Amaranthus retroflexus L., Papaver rhoeas L., Echinochloa crus-galli (L. P.B., Matricaria inodora L., and Galeopsis tetrahit L.

  1. Can global weed assemblages be used to predict future weeds?

    Directory of Open Access Journals (Sweden)

    Louise Morin

    Full Text Available Predicting which plant taxa are more likely to become weeds in a region presents significant challenges to both researchers and government agencies. Often it is done in a qualitative or semi-quantitative way. In this study, we explored the potential of using the quantitative self-organising map (SOM approach to analyse global weed assemblages and estimate likelihoods of plant taxa becoming weeds before and after they have been moved to a new region. The SOM approach examines plant taxa associations by analysing where a taxon is recorded as a weed and what other taxa are recorded as weeds in those regions. The dataset analysed was extracted from a pre-existing, extensive worldwide database of plant taxa recorded as weeds or other related status and, following reformatting, included 187 regions and 6690 plant taxa. To assess the value of the SOM approach we selected Australia as a case study. We found that the key and most important limitation in using such analytical approach lies with the dataset used. The classification of a taxon as a weed in the literature is not often based on actual data that document the economic, environmental and/or social impact of the taxon, but mostly based on human perceptions that the taxon is troublesome or simply not wanted in a particular situation. The adoption of consistent and objective criteria that incorporate a standardized approach for impact assessment of plant taxa will be necessary to develop a new global database suitable to make predictions regarding weediness using methods like SOM. It may however, be more realistic to opt for a classification system that focuses on the invasive characteristics of plant taxa without any inference to impacts, which to be defined would require some level of research to avoid bias from human perceptions and value systems.

  2. Image analysis as a non-destructive method to assess regrowth of weeds after repeated flame weeding

    DEFF Research Database (Denmark)

    Rask, Anne Merete; Kristoffersen, Palle; Andreasen, Christian

    2013-01-01

    picture of the long-term effect of repeated treatments. Image analysis was most useful for assessing the effect of repeated treatments when weed cover was relatively low (below 40%) and when plots contained relatively much withered plant material. However, when weed cover is close to 100%, dry weight......, and therefore it may influence the long-term effect of repeated treatments. Visual assessment of weed cover or image analysis do not affect the remaining parts of the weed plants after treatment, but the methods may have other disadvantages. In order to evaluate and compare three methods we measured changes...... in vegetation cover of perennial ryegrass after flaming by (1) a simple image analysis programme counting green pixels, (2) visual assessment of images and (3) by taking biomass samples. Plants were flame treated with eight different dosages (0, 20, 30, 35, 45, 60, 90 and 180 kg propane ha-1) and with various...

  3. Bioherbicides: Current knowledge on weed control mechanism.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Alqarawi, Abdulaziz A; Abd Allah, Elsayed Fathi

    2018-04-17

    Weed control is a challenging event during crop cultivation. Integrated management, including the application of bioherbicides, is an emerging method for weed control in sustainable agriculture. Plant extracts, allelochemicals and some microbes are utilized as bioherbicides to control weed populations. Bioherbicides based on plants and microbes inhibit the germination and growth of weeds; however,few studies conducted in weed physiology. This review ascribes the current knowledge of the physiological changes in weeds that occur during the exposure to bioherbicides. Plant extracts or metabolites are absorbed by weed seeds, which initiates damage to the cell membrane, DNA, mitosis, amylase activity and other biochemical processes and delays or inhibits seed germination. The growth of weeds is also retarded due to low rates of root-cell division, nutrient uptake, photosynthetic pigment synthesis, and plant growth hormone synthesis, while the productions of reactive oxygen species (ROS) and stress-mediated hormones increase, including irregular antioxidant activity. However, lytic enzymes and toxic substances secreted from microbes degrade the weed seed coat and utilize the endosperm for survival, which inhibits seed germination. The microbes grow through the intercellular spaces to reach the root core, and the deposition of toxins in the cells affects cell division and cellular functions. Some of the metabolites of deleterious microbes cause disease, necrosis and chlorosis,which inhibit the germination and growth of weed seeds by suppressing photosynthesis and gibberellin activities and enhancing ROS, abscisic acid and ethylene. This review explains the effects of bioherbicides (derived from plants and microbes) on weed-plant physiology to elucidate their modes of action. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Water management as a key component of integrated weed management

    Directory of Open Access Journals (Sweden)

    Antonio Berti

    2010-09-01

    Full Text Available Water management within the cropping system is a key factor for an integrated weed management. Soil moisture affects seed persistence and seed dormancy, thus influencing their germination, the establishment of seedlings as well as the competition at adult stage and the number, vitality and dormancy of the new seeds produced by the weeds. The interactions among water availability and competition are very complex and still not fully understood. A research effort in this sector should the be very relevant for the development of new approaches of weed management, such as “Ecological weed management”, aiming to reduce weed density and competitiveness and, in the medium term, to prevent undesired modifications of the weed flora.

  5. Weed Biomass and Weed Species Diversity of Juvenile Citrus Trees Intercrop with some Arable Crops

    Directory of Open Access Journals (Sweden)

    Patience Mojibade OLORUNMAIYE

    2012-02-01

    Full Text Available A preliminary study was carried out to evaluate the performances of eight crops in the intercrop of citrus with arable crops at the National Horticultural Research Institute (NIHORT Ibadan, Nigeria. Eight arable crops: maize, cucumber, sweet potato, Corchorus olitorius, large green, grain amaranth, Mucuna pruriens var. utilis, and groundnut were intercropped with young citrus trees in the early planting season of 2010 with sole citrus as control. The experiment was laid out in a completely randomized block design with three replicates. Data were collected on weed flora, weed density and weed dry weight. Results showed that the relative frequencies of weeds in all the plots were less than 4% at both 6 and 9WAP. Gomphrena celosoides, Oldenlandia corymbosa and Tridax procumbens were most preponderant in appearing in all the plots. Tridax procumbens had a consistent relative frequency (2.34% in all the plots except in citrus/maize plot (0.78% at 9 WAP. Significantly lower broadleaf weed densities were obtained in citrus/sweet potato, citrus/large green, control plot and citrus/cucumber (28.67, 45.00, 50.00 and 76.33 m-2 respectively than in citrus/groundnut plot (143.00 m-2. Similarly, significantly lower grass weed densities were produced in citrus/Mucuna and citrus/sweet potato (0.33 m-2 each plots than the control plot (11.33 m-2. Whereas citrus/corchorus plot produced significantly lower broadleaf weed dry weight (37.59 g m-2 than citrus/Mucuna plot (126.47 g m-2 at 3WAP, citrus/large green plot (16.15 g m-2 and citrus/groundnut plot (123.25 g m-2 followed the same trend at 6 WAP. Sedges dry weights were less than 7 g m-2 in all the plots compared with control plot.

  6. The effect of soil tillage system and weeding time on the growth of weed and yield of soybean (Glycine max (L. Merril

    Directory of Open Access Journals (Sweden)

    Husni Thamrin Sebayang

    2018-04-01

    Full Text Available The growth and yield of soybeans can decrease due to competition from weeds. Various efforts have been made to control the growth of weeds such as land preparation and weeding periods. An experiment to study the effect of soil tillage systems and weeding time on the growth of weeds and soybean crop yield (Glycine max (L. Merril has been done in Wringinsongo Village, Tumpang Sub-District, Malang Regency from February to May 2017. The split-plot design with three replicates was used with the soil tillage system as the main plot consisting of three levels, T0: no tillage, T1: minimum tillage, and T2: conventional tillage, and weeding time as the sub plot consisting of 4 levels, P0: no weeding, P1: weeding 1 time, P2: weeding two times and P3: weeding three times. The results showed that the dominant weed species before treatment were Amaranthus spinosus (Spiny amaranth, Cynodon dactylon (Bermuda grass, Cyperus rotundus (Purple nutsedge, Ageratum conyzoides (Billygoat weed, and Portulaca oleracea (Common purslane. After treatment, the dominant weed species were Cyperus rotundus (Purple nutsedge, Amaranthus spinosus (Spiny amaranth, Ageratum conyzoides (Billygoat weed, Physalis peruviana (Cape gooseberry, and Eclipta alba (False daisy. There was no significant difference of the dry weight of weeds in conventional tillage followed by weeding 3 times at 15, 30 and 45 days after planting, and minimum tillage and no tillage. For the yield of soybeans, conventional tillage followed by weeding 3 times at 15, 30 and 45 days after planting were not significant with that of minimum tillage. The yield of soybeans was lower than that of with no tillage and no weeding.

  7. Effect of three rotation systems on weed seed bank of barely fields in Karaj

    Directory of Open Access Journals (Sweden)

    mostafa oveysi

    2009-06-01

    Full Text Available Rotation can be used as an approach for weed management, because density and combination of weed seed bank may be affected by rotation. In this study effect of rotation in diversity and density of weed seed was studied in three rotation systems (fallow – barely, maize – barely and canola – barely. Results showed that fallow – barely rotation system have high population density in seed bank and highest amount of Shannon diversity index (H = 0.84. In canola – barely rotation system because of different herbicide uses and special traits of canola, population of weed seeds in seed bank was significantly lower that other rotation systems. Results showed that canola – barely rotation system because of combination special herbicide and agronomical and biological characteristic of canola, in comparison with other rotation systems is more successful in decreasing of weed seed bank.

  8. Distribution of parthenium weed in peshawar valley, khyber pakhtunkhwa- pakistan

    International Nuclear Information System (INIS)

    Khan, H.; Marwat, K.B.; Hassan, M.G.; Khan, M.A.; Hashim, S.

    2014-01-01

    Parthenium hysterophorus L. is a weed of national significance in Pakistan. Although infesting many districts of Khyber Pakhtunkhwa province, but more affected districts are Swabi, Mardan, Charsadda and Peshawar where it is highly invasive and invaded most of the open spaces roadsides, etc and threatening the local biodiversity. Field survey of four districts of the Peshawar valley, Khyber Pakhtunkhwa viz. Swabi, Mardan, Charsadda and Peshawar were carried out during May-June, 2009-2010 to study the distribution and invasion of parthenium weed. Twenty five locations were sampled from each district. Data regarding absolute and relative density, frequency, relative frequency, importance valve %, average importance value, constancy classes and importance value constancy index of parthenium weed and other weeds of the area were recorded by using (1x1 m2) quadrate. The mean data across the surveyed districts reveals that the flora is predominated by parthenium weed with the highest relative density of 42.68% among all species. It was followed by Cannabis sativa, Cynodon dactylon and Cyperus rotundus, with relative densities of 15.17, 13.49 and 5.96, respectively. At different locations, it was observed that parthenium weed is competing with Cannabis sativa which is not so aggressive and problematic weed. While in some areas parthenium weed has already replaced Cannabis sativa. Mean distribution data showed that parthenium weed infestation was abundant and almost not uniform in all districts, however highest relative frequency of 26.14% was recorded for parthenium weed followed by Cannabis sativa, Cynodon dactylon and Cyperus rotundus having relative frequency of 15.17, 13.49 and 9.14, respectively. Rumex crispus and Xanthium strumarium infatuated the smallest relative frequency at most of the locations studied thereby indicating them as insignificant among the weed flora of the study area. Importance value data revealed that P. hysterophorus, Cannabis sativa, Cynodon

  9. Distribution of parthenium weed in peshawar valley, khyber pakhtunkhwa- pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Khan, H.; Marwat, K. B.; Hassan, M. G.; Khan, M. A.; Hashim, S. [The University of Agriculture, Peshawar (Pakistan). Dept. of Weed Sciences

    2014-01-15

    Parthenium hysterophorus L. is a weed of national significance in Pakistan. Although infesting many districts of Khyber Pakhtunkhwa province, but more affected districts are Swabi, Mardan, Charsadda and Peshawar where it is highly invasive and invaded most of the open spaces roadsides, etc and threatening the local biodiversity. Field survey of four districts of the Peshawar valley, Khyber Pakhtunkhwa viz. Swabi, Mardan, Charsadda and Peshawar were carried out during May-June, 2009-2010 to study the distribution and invasion of parthenium weed. Twenty five locations were sampled from each district. Data regarding absolute and relative density, frequency, relative frequency, importance valve %, average importance value, constancy classes and importance value constancy index of parthenium weed and other weeds of the area were recorded by using (1x1 m2) quadrate. The mean data across the surveyed districts reveals that the flora is predominated by parthenium weed with the highest relative density of 42.68% among all species. It was followed by Cannabis sativa, Cynodon dactylon and Cyperus rotundus, with relative densities of 15.17, 13.49 and 5.96, respectively. At different locations, it was observed that parthenium weed is competing with Cannabis sativa which is not so aggressive and problematic weed. While in some areas parthenium weed has already replaced Cannabis sativa. Mean distribution data showed that parthenium weed infestation was abundant and almost not uniform in all districts, however highest relative frequency of 26.14% was recorded for parthenium weed followed by Cannabis sativa, Cynodon dactylon and Cyperus rotundus having relative frequency of 15.17, 13.49 and 9.14, respectively. Rumex crispus and Xanthium strumarium infatuated the smallest relative frequency at most of the locations studied thereby indicating them as insignificant among the weed flora of the study area. Importance value data revealed that P. hysterophorus, Cannabis sativa, Cynodon

  10. Changes in weed infestation of common bean (Phaseolus vulgaris L. under conditions of strip intercropping and different weed control methods

    Directory of Open Access Journals (Sweden)

    Aleksandra Głowacka

    2012-12-01

    Full Text Available The experiment was conducted in the years 2004-2006 in a private farm in the village of Frankamionka in Zamość district. There were two experimental factors: I. Cultivation methods - sole cropping and strip intercropping; and II. Tending methods - mechanical, mechanical-chemical, and chemical weed control. The subject of the study was weed infestation of the Mela variety of common bean. Beans were sown between 30 April and 5 May. Weed infestation was assessed in the last week before harvesting by determining its floristic composition and the frequency of occurrence of particular weed species, as well as the air-dry weight of weeds. The dominant weed species were Galinsoga parviflora, Echinochloa crus-galli, Chenopodium album, and Amaranthus retroflexus, which comprised 84.7% of the total number of weeds. Strip intercropping markedly reduced the number of weeds per unit area (by 50%, as well as the dry weight of their aerial parts. The most effective method of weed control was the mechanical-chemical method, which resulted in the lowest occurrence of weeds. It also significantly reduced the weight of weeds.

  11. Effect of Weed Interference on Yield and Agronomical Characteristics of Fenugreek (Trigonella foenum gracum in Different Plant Density under Birjand Conditions

    Directory of Open Access Journals (Sweden)

    R Baradaran

    2016-02-01

    grain yield, plant height, biological yield, number of branches per plant and harvest index were measured. Ultimate performance were measured when the plant pods were yellow and dried. At the beginning of each plot five plants randomly chosen to measure the morphological characteristics and traits in yield components were recorded and then removed 50 cm of the margins of the plot, the rest were taken to determine the function. Analysis of variance and statistical analysis was performed using SAS and Excel softwares, Mean comparison was done by Duncan test at 5 percent. Results and Discussion Analysis of variance showed that the density and weed interference were significant at 1 and 5 percent, respectively. The interaction between density and weed interference on yield was significant at 5% level too. By prolonging the period of weed interference, the yield fell to the lowest amount of weeding treatments. The significance of the interaction between density and weed interference represents different responses in different levels of compression performance is to weed competition. In general, the choice of planting density and suitable crop can reduce weeds, increase competitive ability of the crop and increase its performance. Biological yield was significantly affected by the plant density. The density of planting, the maximum density of 40 plants (325.56 grams per square meter and the lowest density of 10 plants (232.66 grams per square meter and biomass production. Biological yield was not affected significantly by weed interference. Although by increasing time interval of weeding time (up to 20 days biological yield decreased from 280.49 to 257.49, but this reduction was not significant. The interaction between planting density and weed interference on biological performance was not significant. Most biological yield was achieved in the absence of weeds. This is not unexpected because the availability of a large part of the resources cause more shoots in plant during

  12. Weed infestation of onion in soil reduced cultivation system

    Directory of Open Access Journals (Sweden)

    Marzena Błażej-Woźniak

    2013-12-01

    Full Text Available Field experiment was conducted in the years 1998-2000 in GD Felin. The influence of no-tillage cultivation and conventional tillage with spring ploughing on weed infestation of onion was compared. In experiment four cover crop mulches (Sinapis alba L., Vicia sativa L., Phacelia tanacetifolia B., Avena sativa L. were applied. From annual weeds in weed infestation of onion in great number Matricaria chamomilla L., and Senecio vulgaris L. stepped out. and from perennial - Agropyron repens (L.P.B. Reduced soil cultivation system (no-tillage caused the significant growth of primary weed infestation of onion in comparison with conventional tillage. In all years of investigations the executed pre-sowing ploughing limited significantly the annual weeds' number in primary weed infestation. The applied mulches from cover plants limited in considerable degree the number of primary weed infestation. In all years of investigations the most weeds stepped out on control object. Among investigated cover crop mulches Vicia sativa L. and Avena sativa L. had a profitable effect on decrease of onion`s primary weed infestation. Soil cultivation system and cover crop mulches had no signi ficant residual influence on the secondary weed infestation of onion.

  13. Aquatic weed control within an integrated water management framework

    NARCIS (Netherlands)

    Querner, E.P.

    1993-01-01

    Aquatic weed control, carried out by the water boards in the Netherlands, is required to maintain sufficient discharge capacity of the surface water system. Weed control affects the conditions of both surface water and groundwater. The physically based model MOGROW was developed to simulate

  14. Comparison of some Vegetative and Reproductive Traits of Dominant Weeds in Cultivated Tomato as Influence by Metribuzin and Non-living Mulches

    Directory of Open Access Journals (Sweden)

    R. Zangoueinejad

    2016-03-01

    Full Text Available Introduction: Tomato production, similar to other important crops, is affected by weed competition in the early season. Weed infestation can affect tomato yield significantly. So weed control can be one of the most important factors in improving of crop production. Nowadays pre-plant, post-plant and post-emergence herbicides are widely used for controlling weeds in tomato fields, but it can lead to increasing environmental hazards, making weed resistant to herbicides and injuring tomato plants. Therefore, the use of non-living mulch (organic mulch and inorganic mulch could be a suitable substitutional way to weed control. Material and method: In this study, in order to investigating the time of emergence, flowering, seed shattering, length of vegetative and reproductive growth period of weeds under six types of non-living mulches (black plastic mulch, clear plastic mulch, wheat straw, sawdust, coco peat and peat moss and mtribuzin in tomato, research was conducted in a randomized complete block design with three replications at College of Agriculture, Shiraz University in 2012. The plots were fertilized with 20:20:20 (N, P2O5 and K2O with concentration of 166 kg ha-1. In this study, the appearance of plumule (for narrow leaf weeds and hypocotyl (for broad leaf weeds from weed seeds in soil medium was considered as the time of emergence. The weeds were visited once a week since transplanting tomato seedlings to the farm and the related date was recorded. Flowering time recording for each weed species was carried out after flowering. Plots without mulch (weedy and weed free were used as control. Statistical analysis of the collected data was performed by using SAS 9.1 software and comparing of the mean of characteristics was done by Tukey's test at 5 % significant level. Result and discussion: The longest and shortest time of weed emergence respectively belonged to the clear plastic mulch (28 days after transplanting and organic mulches and

  15. Foliar Potassium Fertilizer Additives Affect Soybean Response and Weed Control with Glyphosate

    Directory of Open Access Journals (Sweden)

    Kelly A. Nelson

    2012-01-01

    Full Text Available Research in 2004 and 2005 determined the effects of foliar-applied K-fertilizer sources (0-0-62-0 (%N-%P2O5-%K2O-%S, 0-0-25-17, 3-18-18-0, and 5-0-20-13 and additive rates (2.2, 8.8, and 17.6 kg K ha−1 on glyphosate-resistant soybean response and weed control. Field experiments were conducted at Novelty and Portageville with high soil test K and weed populations and at Malden with low soil test K and weed populations. At Novelty, grain yield increased with fertilizer additives at 8.8 kg K ha−1 in a high-yield, weed-free environment in 2004, but fertilizer additives reduced yield up to 470 kg ha−1 in a low-yield year (2005 depending on the K source and rate. At Portageville, K-fertilizer additives increased grain yield from 700 to 1160 kg ha−1 compared to diammonium sulfate, depending on the K source and rate. At Malden, there was no yield response to K sources. Differences in leaf tissue K (P=0.03, S (P=0.03, B (P=0.0001, and Cu (P=0.008 concentrations among treatments were detected 14 d after treatment at Novelty and Malden. Tank mixtures of K-fertilizer additives with glyphosate may provide an option for foliar K applications.

  16. Effect of Planting Date and Weed Control Methods on Yield and Agronomic Traits of Sunflower (Helianthus annuus L. in Khoy Region

    Directory of Open Access Journals (Sweden)

    M. Akbari

    2010-12-01

    Full Text Available Effects of planting dates and weed control methods on yield and agronomic traits of sunflower was investigated. A factorial experiment based on a complete randomized blocks design with four replications was conducted in 2009. Treatments consisted of three planting date (April 4th, May5th and Juns5th and five weed control methods, Trifluralin (2 Lit/ha + Fokus (1.5 Lit/ha, Trifluralin+Nabu-s (3Lit/ha, Trifluralin, Hand weeding and without control. Results indicated that planting dates and weed control methods significantly affected head diameter, 100 grain weight, seed number per head and grain yield. Harvest index and oil percent was affected only by planting dates. The highest grain yield (630.1 g/m2, was produced in the second planting date (May 5 by using Trifluralin+Fokus. Delaying sowing date (after May 5 significantly decreased grain yield. The most important weeds in the experimental site were common lambsquarter (Chenopodium album, field bind weed (Convolvulus arvensis, bastard cabbage (Rapistrum rugosum, flower-of-an-hour (Hibiscus trionum, cockspur grass (Echinochloa colorum and green bristle grass (Setaria verticillata. It was observed that the dry matter weight sharply varied in all weed species in different planting dates, that is, in the 4th April the dry matter production of common lambsquarter and bastard cabbage, in June 5th planting date were maximum. Dry matter of broad leaf and narrow leaf weeds in the date of May 5th was lower than the other two planting dates. The interaction of planting date ×control methods on head diameter, seed number per head, grain yield and weeds dry matter was significant.

  17. Effects of nitrogen application method and weed control on corn yield and yield components.

    Science.gov (United States)

    Sepahvand, Pariya; Sajedi, Nurali; Mousavi, Seyed Karim; Ghiasvand, Mohsen

    2014-04-01

    The effects of nitrogen fertilizer application and different methods for weed control on yield and yield components of corn was evaluated in Khorramabad in 2011. The experiment was conducted as a split plot based on randomized complete block design in 3 replications. Nitrogen application was as main plot in 4 levels (no nitrogen, broadcasting nitrogen, banding nitrogen and sprayed nitrogen) and methods of weed control were in 4 levels (non-control weeds, application Equip herbicide, once hand control of weeds and application Equip herbicide+once time weeding) was as subplots. Result illustrated that effects of nitrogen fertilizer application were significant on grain and forage yield, 100 seeds weight, harvest index, grain number per row and cob weight per plant. Grain yield increased by 91.4 and 3.9% in application banding and broadcasting for nitrogen fertilizer, respectively, compared to the no fertilizer treatment. The results show improved efficiency of nitrogen utilization by banding application. Grain yield, harvest index, seed rows per cob, seeds per row and cob weight were increased by weed control. In the application of Equip herbicide+ hand weeding treatment corn grain yield was increased 126% in comparison to weedy control. It represents of the intense affects of weed competition with corn. The highest corn grain yield (6758 kg h(-1)) was related to the application banding of nitrogen fertilizer and Equip herbicide+once hand weeding.

  18. Crop–weed competition

    DEFF Research Database (Denmark)

    Gallandt, Eric R.; Weiner, Jacob

    2015-01-01

    importantly, weed density and time of emergence relative to the crop. Practices that (1) reduce the density of weeds, (2) maximise occupation of space or uptake of resources by the crop or (3) establish an early-season size advantage of the crop over the weeds will minimise the competitive effects of weeds...... on crops. Longer term management of crop–weed competition can be achieved through crop rotations, specifically crop sequences that reduce the weed seed bank, and therefore seedling density, and prevent proliferation of perennial weeds. Key ConceptsKey Concepts * Plant growth requires sunlight, water...... an early-season competitive advantage to the crop and (3) maximising resource capture by the crop using competitive species, competitive cultivars, high sowing densities, optimal spatial arrangement, intercropping complimentary species or transplanting....

  19. Soil solarization for weed control in carrot

    Directory of Open Access Journals (Sweden)

    MARENCO RICARDO ANTONIO

    2000-01-01

    Full Text Available Soil solarization is a technique used for weed and plant disease control in regions with high levels of solar radiation. The effect of solarization (0, 3, 6, and 9 weeks upon weed populations, carrot (Daucus carota L. cv. Brasília yield and nematode infestation in carrot roots was studied in São Luís (2º35' S; 44º10' W, MA, Brazil, using transparent polyethylene films (100 and 150 mm of thickness. The maximum temperature at 5 cm of depth was about 10ºC warmer in solarized soil than in control plots. In the study 20 weed types were recorded. Solarization reduced weed biomass and density in about 50% of weed species, including Cyperus spp., Chamaecrista nictans var. paraguariensis (Chod & Hassl. Irwin & Barneby, Marsypianthes chamaedrys (Vahl O. Kuntze, Mitracarpus sp., Mollugo verticillata L., Sebastiania corniculata M. Arg., and Spigelia anthelmia L. Approximately 40% of species in the weed flora were not affected by soil mulching. Furthermore, seed germination of Commelina benghalensis L. was increased by soil solarization. Marketable yield of carrots was greater in solarized soil than in the unsolarized one. It was concluded that solarization for nine weeks increases carrot yield and is effective for controlling more than half of the weed species recorded. Mulching was not effective for controlling root-knot nematodes in carrot.

  20. Weed control in rose-scented geranium (Pelargonium spp).

    Science.gov (United States)

    Kothari, Sushil K; Singh, Chandra P; Singh, Kamla

    2002-12-01

    Abstract: Field investigations were carried out during 1999 and 2000 to identify effective chemical/ cultural methods of weed control in rose-scented geranium (Pelargonium spp). The treatments comprised pre-emergence applications of oxyfluorfen (0.15, 0.20 and 0.25 kg AI ha(-1)) and pendimethalin (0.50, 0.75 and 1.00kg AI ha(-1)), successive hand weeding, hoeing and mulching using spent of lemon grass (at 5 tonnes ha(-1)) 45 days after planting (DAP), three hand-weedings 30, 60 and 90 DAP, weed-free (frequent manual weeding) and weedy control. Broad-leaf weeds were more predominant than grass and sedge weeds, accounting for 85.8% weed density and 93.0% weed dry weight in 1999 and 77.2% weed density and 93.9% weed dry weight in 2000. Unrestricted weed growth significantly reduced geranium oil yield, by 61.6% and 70.6% in 1999 and 2000, respectively. Pre-emergence application of pendimethalin (0.75-1.00 kgAI ha(-1)) or oxyfluorfen (0.25 kg AI ha(-1)), successive hand-weeding, hoeing and mulching and three hand-weedings were highly effective in reducing weed density and dry weight and gave oil yield comparable to the weed-free check. Application of oxyfluorfen (0.15 or 0.20 kg AI ha(-1)) and pendimethalin (0.50 kg AI ha(-1)) were less effective in controlling the weed species in geranium. None of the herbicides impaired the quality of rose-scented geranium oil measured in terms of citronellol and geraniol content.

  1. Allelopathic cover crop of rye for integrated weed control in sustainable agroecosystems

    Directory of Open Access Journals (Sweden)

    Vincenzo Tabaglio

    2013-02-01

    Full Text Available The allelopathic potential of rye (Secale cereale L. is mainly due to phytotoxic benzoxazinones, compounds that are produced and accumulated in young tissues to different degrees depending on cultivar and environmental influences. Living rye plants exude low levels of benzoxazinones, while cover crop residues can release from 12 to 20 kg ha–1. This paper summarizes the results obtained from several experiments performed in both controlled and field environments, in which rye was used as a cover crop to control summer weeds in a following maize crop. Significant differences in benzoxazinoid content were detected between rye cultivars. In controlled environments, rye mulches significantly reduced germination of some broadleaf weeds. Germination and seedling growth of Amaranthus retroflexus and Portulaca oleracea were particularly affected by the application of rye mulches, while Chenopodium album was hardly influenced and Abutilon theophrasti was advantaged by the presence of the mulch. With reference to the influence of agronomic factors on the production of benzoxazinoids, nitrogen fertilization increased the content of allelochemicals, although proportionally less than dry matter. The field trial established on no-till maize confirmed the significant weed suppressiveness of rye mulch, both for grass and broadleaf weeds. A significant positive interaction between nitrogen (N fertilization and notillage resulting in the suppression of broadleaf weeds was observed. The different behavior of the weeds in the presence of allelochemicals was explained in terms of differential uptake and translocation capabilities. The four summer weeds tested were able to grow in the presence of low amounts of benzoxazolin-2(3H-one (BOA, between 0.3 and 20 mmol g–1 fresh weight. Although there were considerable differences in their sensitivity to higher BOA concentrations, P. oleracea, A. retroflexus, and Ch. album represented a group of species with a consistent

  2. About the value of species diversity in arable weeds for weed management

    Directory of Open Access Journals (Sweden)

    Gerowitt, Bärbel

    2016-02-01

    Full Text Available Arable weeds accompany arable land use – we define them based on their affiliation to ar able systems. They are adapted to such a degree that most of them cannot exist without arable land use. Weeds are part of the total biodiversity on arable fields, as primary producers they are basic for important functions within the ecosystem. This paper elaborates the relevance of species diversity in arable weeds for their management. Arable systems can be regarded for the number of different methods for preventive and direct weed control which are realized. Historical arable land use is roughly divided into three periods, which differ concerning the diversity of weed management and the occurring diversity in weed species. Obviously divers weed management in arable systems and diversity in weed species depend on each other, this is illustrated with a simple abstract picture. Arable systems, which are characterised by simpleness, favor the domination of few species which ensure an effective use of the resources within the ecosystem. One consequence under continuous pressure of an overused tool in weed management is that the genetic diversity within a dominating weed population is exploited to ensure this resource use. Current herbicides represent this tool – the results are herbicide resistant biotypes within the weed populations. Species diversity in arable weeds as a rationale within arable production can assist to prevent this development.

  3. The weeding handbook a shelf-by-shelf guide

    CERN Document Server

    Vnuk, Rebecca

    2015-01-01

    "No! We can't rid of that!" Vnuk, author of the popular "Weeding Tips" column on Booklist Online, is here to show you that yes, you can. A library is an ever-changing organism; when done the right way, weeding helps a library thrive by focusing its resources on those parts of the collection that are the most useful to its users. Her handbook takes the guesswork out of this delicate but necessary process, giving public and school library staff the knowledge and the confidence to effectively weed any collection, of any size. Going through the proverbial stacks shelf by shelf, Vnuk: Explains why weeding is important for a healthy library, demonstrating that a vibrant collection leads to robust circulation, which in turn affects library budgets Walks readers through a library's shelves by Dewey area, with recommended weeding criteria and call-outs in each area for the different considerations of large collections and smaller collections Features a chapter addressing reference, media, magazines and newspapers, e-b...

  4. of different weed control methods on Weed infestation, growth

    African Journals Online (AJOL)

    thinkexploitsint'l

    This weed control method also resulted in significantly better growth and ... proper management, it is possible to obtain 2,500 kg ha-1 (Onwueme and Sinha, 1991). ... however, time consuming, labour – intensive, strenuous and generally ...

  5. Weeds and ground-dwelling predators' response to two different weed management systems in glyphosate-tolerant cotton: A farm-scale study.

    Science.gov (United States)

    García-Ruiz, Esteban; Loureiro, Íñigo; Farinós, Gema P; Gómez, Pablo; Gutiérrez, Elena; Sánchez, Francisco Javier; Escorial, María Concepción; Ortego, Félix; Chueca, María Cristina; Castañera, Pedro

    2018-01-01

    The use of glyphosate, as a post-emergence broad-spectrum herbicide in genetically modified glyphosate-tolerant (GT) cotton, supposes a big change in weed management programs with respect to a conventional regime. Thus, alterations in arable flora and arthropod fauna must be considered when evaluating their potential impacts. A 3-year farm-scale study was conducted in a 2-ha GT cotton crop, in southern Spain, to compare the effects of conventional and glyphosate herbicide regimes on weed abundance and diversity and their consequences for ground-dwelling predators. Surveys reveal that weed density was relatively low within all treatments with a few dominant species, with significantly higher weed densities and modifications of the floristic composition in glyphosate-treated plots that led to an increase in the abundance of Portulaca oleracea and to a reduction in plant diversity. The activity-density of the main predatory arthropod taxa (spiders, ground beetles, rove beetles and earwigs) varied among years, but no significant differences were obtained between conventional and glyphosate herbicide regimes. However, significant differences between treatments were obtained for ground beetles species richness and diversity, being higher under the glyphosate herbicide regime, and a positive correlation with weed density could be established for both parameters. The implications of these findings to weed control in GT cotton are discussed.

  6. Reducing tillage intensity affects the cumulative emergence dynamics of annual grass weeds in winter cereals

    DEFF Research Database (Denmark)

    Scherner, A; Melander, B; Jensen, P K

    2017-01-01

    Annual grass weeds such as Apera spica-venti and Vulpia myuros are promoted in non-inversion tillage systems and winter cereal-based crop rotations. Unsatisfactory weed control in these conditions is often associated with a poor understanding of the emergence pattern of these weed species. The aim...... with a higher total emergence seen under direct drilling, followed by pre-sowing tine cultivation and ploughing. The emergence patterns of all species were differently influenced by the tillage systems, suggesting that under direct drilling, in which these species occur simultaneously, management interventions...

  7. THE EFFECT OF WINTER CATCH CROPS ON WEED INFESTATION IN SWEET CORN DEPENDING ON THE WEED CONTROL METHODS

    Directory of Open Access Journals (Sweden)

    Robert Rosa

    2015-02-01

    Full Text Available An experiment was carried out in east-central Poland (52°06’ N, 22°55’ E over 2008–2011 to study the effect of winter catch crops on the weed infestation, number, and fresh matter of weeds in sweet corn (Zea mays L. var. saccharata. The following winter catch crops were grown: hairy vetch (Vicia villosa Roth., white clover (Trifolium repens L., winter rye (Secale cereale L., Italian ryegrass (Lolium multiflorum L. and winter turnip rape (Brassica rapa var. typica Posp.. The catch crops were sown in early September and incorporated in early May. The effect of the catch crops was compared to the effect of FYM (30 t·ha-1 and control without organic manuring (NOM. Three methods of weed control were used: HW – hand weeding, twice during the growing period, GCM – the herbicide Guardian Complete Mix 664 SE, immediately after sowing of corn seeds, Z+T – a mixture of the herbicides Zeagran 340 SE and Titus 25 WG applied at the 3–4-leaf stage of sweet corn growth. Rye and turnip rape catch crops had least weeds in their fresh matter. Sweet corn following winter catch crops was less infested by weeds than corn following farmyard manure and non-manured corn. Least weeds and their lowest weight were found after SC, BRT and VV. LM and BRT reduced weed species numbers compared with FYM and NOM. The greatest weed species diversity, determined at the corn flowering stage, was determined after SC and FYM. The number and weight of weeds were significantly lower when chemically controlled compared with hand weeding. The best results were observed after a post-emergent application of the mixture Z+T. The weed species diversity on Z+T-treated plots was clearly lower compared with GCM and HW.

  8. Weed infestation of spring common wheat (Triticum aestivum L. grown in monoculture depending on the cover crop and weed control method

    Directory of Open Access Journals (Sweden)

    Dorota Gawęda

    2012-10-01

    Full Text Available The aim of this 3-year field study was to evaluate the effect of some stubble crops and in-crop weed control methods on the species composition, number and air-dry weight of weeds in a wheat crop grown in short-term monoculture. The study was conducted in the period 2009-2011 in the Uhrusk Experimental Farm on mixed rendzina soil classified as very good rye soil complex. It included various types of stubble crops ploughed in each year (control treatment without cover crop, white mustard, lacy phacelia, a mixture of legumes – narrow-leaf lupin + field pea and methods of weed control in spring wheat (mechanical, mechanical and chemical, chemical weed control. On average during the study period, all stubble crops used reduced the air-dry weight of weds in the treatments with mechanical weed management relative to the control treatment. Irrespective of the weed control method, the number of weeds in the wheat crop was significantly lower only after the ploughing in of white mustard. Mechanical weed management proved to be less effective in reducing the number and dry weight of weeds compared to other weed control methods. The white mustard and legume mixture cover crops had a reducing effect on the number of weed species in relation to the treatment without cover crops. The highest floristic diversity of weed communities was found in the spring wheat crop in which only mechanical weeding alone was used.

  9. Xanthium strumarium: a weed host of components of begomovirus-betasatellite complexes affecting crops.

    Science.gov (United States)

    Mubin, M; Akhtar, S; Amin, I; Briddon, R W; Mansoor, S

    2012-02-01

    Xanthium strumarium is a common weed that often shows symptoms typical of begomovirus infection, such as leaf curling and vein thickening. The virus complex isolated from the weed consisted of two begomoviruses along with a betasatellite and an alphasatellite. The first begomovirus was shown to be an isolate of Cotton leaf curl Burewala virus, a new recombinant begomovirus species that is associated with resistance breaking in previously resistant cotton varieties in Pakistan, whereas the second was shown to be an isolate of Tomato leaf curl Gujarat virus (ToLCGV), a begomovirus previously reported to be bipartite. However, there was no evidence for the presence of the second genomic component, DNA B, of ToLCGV in X. strumarium. The betasatellite was shown to be an isolate of Tomato yellow leaf curl Thailand betasatellite, the first time this satellite has been identified in Pakistan. The alphasatellite associated with infection of X. strumarium was shown to be a species recently identified in potato and various weeds; Potato leaf curl alphasatellite. Although each component has been identified previously, this is the first time they have been identified in a single host. These findings reinforce the hypothesis that weeds are reservoirs of crop-infecting begomoviruses that may contribute to virus diversity by virtue of harboring multiple viruses and virus associated components, which may lead to interspecific recombination and component exchange.

  10. Non-chemical weed management

    DEFF Research Database (Denmark)

    Melander, Bo; Liebman, Matt; Davies, Adam S.

    2017-01-01

    Non-chemical weed management covers all management practices that influence weeds except herbicides. This chapter summarises the major achievements in European research, as well as work undertaken in North America. Research groups from both continents have interacted strongly on the topic over...... and in some cases amenity areas as well. Preventive methods reduce weed germination, cultural methods improve crop competition and direct physical weed control reduces weed survival. Non-chemical weed management is mainly adopted in organic crop production, as conventional growers still perceive it as more...

  11. Site-specific weed control technologies

    DEFF Research Database (Denmark)

    Christensen, Svend; Søgaard, Henning Tangen; Kudsk, Per

    2009-01-01

    Site-specific weed control technologies are defined as machinery or equipment embedded with technologies that detect weeds growing in a crop and, taking into account predefined factors such as economics, takes action to maximise the chances of successfully controlling them. In the article, we...... describe the basic parts of site specific weed control technologies, comprising of weed sensing systems, weed management models and precision weed control implements. A review of state-of-the-art technologies shows that several weed sensing systems and precision implements have been developed over the last...... of knowledge about the economic and environmental potential for increasing the resolution of weed control. The integration of site-specific information on weed distribution, weed species composition and density, and the effect on crop yield, is decisive for successful site-specific weed management.   Keywords...

  12. Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

    Science.gov (United States)

    Veiga, Rita S. L.; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G. A.

    2011-01-01

    Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between −22 and −35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID

  13. Weeds and ground-dwelling predators′ response to two different weed management systems in glyphosate-tolerant cotton: A farm-scale study

    Science.gov (United States)

    Farinós, Gema P.; Gómez, Pablo; Gutiérrez, Elena; Sánchez, Francisco Javier; Escorial, María Concepción; Ortego, Félix; Chueca, María Cristina; Castañera, Pedro

    2018-01-01

    The use of glyphosate, as a post-emergence broad-spectrum herbicide in genetically modified glyphosate-tolerant (GT) cotton, supposes a big change in weed management programs with respect to a conventional regime. Thus, alterations in arable flora and arthropod fauna must be considered when evaluating their potential impacts. A 3-year farm-scale study was conducted in a 2-ha GT cotton crop, in southern Spain, to compare the effects of conventional and glyphosate herbicide regimes on weed abundance and diversity and their consequences for ground-dwelling predators. Surveys reveal that weed density was relatively low within all treatments with a few dominant species, with significantly higher weed densities and modifications of the floristic composition in glyphosate-treated plots that led to an increase in the abundance of Portulaca oleracea and to a reduction in plant diversity. The activity-density of the main predatory arthropod taxa (spiders, ground beetles, rove beetles and earwigs) varied among years, but no significant differences were obtained between conventional and glyphosate herbicide regimes. However, significant differences between treatments were obtained for ground beetles species richness and diversity, being higher under the glyphosate herbicide regime, and a positive correlation with weed density could be established for both parameters. The implications of these findings to weed control in GT cotton are discussed. PMID:29351549

  14. A non-chemical system for online weed control.

    Science.gov (United States)

    Rueda-Ayala, Victor; Peteinatos, Gerassimos; Gerhards, Roland; Andújar, Dionisio

    2015-03-30

    Non-chemical weed control methods need to be directed towards a site-specific weeding approach, in order to be able to compete the conventional herbicide equivalents. A system for online weed control was developed. It automatically adjusts the tine angle of a harrow and creates different levels of intensity: from gentle to aggressive. Two experimental plots in a maize field were harrowed with two consecutive passes. The plots presented from low to high weed infestation levels. Discriminant capabilities of an ultrasonic sensor were used to determine the crop and weed variability of the field. A controlling unit used ultrasonic readings to adjust the tine angle, producing an appropriate harrowing intensity. Thus, areas with high crop and weed densities were more aggressively harrowed, while areas with lower densities were cultivated with a gentler treatment; areas with very low densities or without weeds were not treated. Although the weed development was relatively advanced and the soil surface was hard, the weed control achieved by the system reached an average of 51% (20%-91%), without causing significant crop damage as a result of harrowing. This system is proposed as a relatively low cost, online, and real-time automatic harrow that improves the weed control efficacy, reduces energy consumption, and avoids the usage of herbicide.

  15. Effects of Corn Canopy on Seedling Emergence of Seven Weed Species

    Directory of Open Access Journals (Sweden)

    F Kordbacheh

    2012-02-01

    Full Text Available In this research corn were planted in 3 densities (8, 12, 16 plant/m2 in two planting patterns (single and double-row with seven summer weed species, including redroot pigweed, green foxtail, annual bluegrass, common lambsquarter, jimsonweed, black nightshade and johnsongrass were planted. Temperature, quality and quantity of light reaching to soil surface were measured and the number of emerged seedlings for each weed species was countered in three sampling dates. Temperature fluctuation wasn't affected by density and planting patterns and was reduced with canopy formation. In all weed species 3 seedling emergence patterns were observed. In small seed species, redroot pigweed had one germination flush, so it was not respond to crop canopy. The number of emerged weed seedlings of annual bluegrass, common lambsquarter and green foxtail were significantly higher in bareground than under corn canopy. In double-row planting pattern was higher compared to the single-row and had three germination flushes. The number of emerged seedlings in the species with relatively large seeds had no significant difference between bareground and under corn canopy in jimsonweed and black nightshade. But it increased in johnsongrass under corn canopy compare to the bare ground. In all three species it was higher in double-row compare to single-row pattern. Jimsonweed had three germination flushes but blacknightshade and johnsongrass had 1 germination flush.

  16. Effect of plant spacing and weeding frequency on weed infestation ...

    African Journals Online (AJOL)

    Common bean is an important food and cash crop in eastern Ethiopia. However, its yield is constrained by weeds. Therefore, this study was conducted in 2012 main cropping season at Haramaya and Hirna research fields, eastern Ethiopia, to determine the effect of plant spacing and weeding frequency on weeds, yield ...

  17. Horny Goat Weed

    Science.gov (United States)

    Horny goat weed is an herb. The leaves are used to make medicine. As many as 15 horny goat weed species are known as “yin yang huo” in Chinese medicine. Horny goat weed is used for weak back and knees, ...

  18. The weed composition in an orchard as a result of long-term foliar herbicide application

    Directory of Open Access Journals (Sweden)

    Maria Licznar-Małańczuk

    2016-09-01

    Full Text Available The weed composition and the dominance of individual species occurring in an orchard were assessed at the Research Station of the Wrocław University of Environmental and Life Sciences, Poland, during the first 10 years after orchard establishment. ‘Ligol’ apple trees were planted in the spring of 2004 (3.5 × 1.2 m. Foliar herbicides were applied in 1 m wide tree rows twice or three times per each vegetation period. In the inter-row spaces, perennial grass was maintained. Ten years of maintenance of herbicide fallow contributed to a change in the weed composition in the orchard. It changed as a result of different responses of the most important weed species to the foliar herbicides. Total suppression of Elymus repens was observed in the first year after planting the trees. Convolvulus arvensis, Cirsium arvense, and other perennial weeds, completely disappeared in the succeeding periods. The maintenance of herbicide fallow did not affect the abundance of Taraxacum officinale. The percentage of the soil surface covered by Trifolium repens and Epilobium adenocaulon, perennial weeds with considerable tolerance to post-emergence herbicides, increased during the fruit-bearing period of the trees. The abundance of these weeds was significantly reduced only in the rows with the stronger growing trees on the semi-dwarf P 2 rootstock. Stellaria media was the dominant annual weed. Senecio vulgaris, Poa annua, Capsella bursa-pastoris, and Lamium spp. were also frequently observed. A significant increase in the abundance of annual and perennial weeds was found in the tree rows as a result of improved water availability after a period of high precipitation.

  19. WeedML: a Tool for Collaborative Weed Demographic Modeling

    OpenAIRE

    Holst, Niels

    2010-01-01

    WeedML is a proposed standard to formulate models of weed demography, or maybe even complex models in general, that are both transparent and straightforward to re-use as building blocks for new models. The paper describes the design and thoughts behind WeedML which relies on XML and object-oriented systems development. Proof-of-concept software is provided as open-source C++ code and executables that can be downloaded freely.

  20. Weed Control with Cover Crops in Irrigated Potatoes

    Directory of Open Access Journals (Sweden)

    G.H. Mehring

    2016-01-01

    Full Text Available Field experiments at Oakes, ND, USA in 2010 and Carrington, ND, USA in 2011 were conducted to evaluate the potential for cover crops grown in the Northern Great Plains, USA in order to reduce weed emergence and density in irrigated potatoes. Treatments included five cover crop treatments and three cover crop termination treatments. Termination of cover crops was done with glyphosate, disk-till, and roto-till. Cover crop biomass accumulation was greatest for rye/canola and triticale at Oakes, and hairy vetch and hairy vetch/rye at Carrington. Cover crop and termination affected weed control 14, 29, and 51 days after planting (DAP at Oakes. Weed control at Carrington was at least 90% for all cover crop and termination treatments at all three evaluation timings. Marketable yield at Oakes was greater when roto-till was used to terminate the cover crops compared with disk-till or herbicide, which is beneficial for organic systems where herbicides are not used. Marketable yield at Carrington was not affected by cover crop or termination treatments. Results suggest that cover crops can successfully be integrated into irrigated potato production for weed control with yields equal to no cover crop, and with attention to potential mechanical difficulties.

  1. Weed supression by smother crops and selective herbicides

    Directory of Open Access Journals (Sweden)

    Severino Francisco José

    2004-01-01

    Full Text Available Using a smother crop is thought to suppress weed density and to add other beneficial effects in sustainable agricultural systems. Weed suppression ought to be considered an essential component of integrated weed management. However, very little is known about the effects of green manure plants on weeds. This study evaluated the influence of three green manure species on weed suppression and selectivity of herbicides. A field experiment was designed to determine the effect of the green manure species Crotalaria juncea, Arachis pintoi and pigeon pea on the weeds Brachiaria decumbens, guineagrass and hairy beggarticks, and on the natural weed infestation in the inter rows area of an avocado orchard. The weed species were suppressed differently by each green manure species. Soil samples collected from the field experiment presented a residual effect, of at least 30 d, in suppressing weed seed bank recruitment; this residual effect was caused by the residues of the green manure present in the soil. When the green manure was incorporated into the top 5 cm of soil or left on the surface, in a greenhouse experiment, the emergence of weed seeds was significantly inhibited, depending on the species, and on the amount and depth of green manure incorporation. Greenhouse experiments indicate that pre-emergence herbicides cause lower phytotoxicity than post-emergence Arachis pintoi. Smother crops using green manure species, when well established in an area, provide additional weed control to the cropping system and are effective and valuable tools in integrated weed management.

  2. Emerging Challenges and Opportunities for Education and Research in Weed Science

    Directory of Open Access Journals (Sweden)

    Bhagirath S. Chauhan

    2017-09-01

    Full Text Available In modern agriculture, with more emphasis on high input systems, weed problems are likely to increase and become more complex. With heightened awareness of adverse effects of herbicide residues on human health and environment and the evolution of herbicide-resistant weed biotypes, a significant focus within weed science has now shifted to the development of eco-friendly technologies with reduced reliance on herbicides. Further, with the large-scale adoption of herbicide-resistant crops, and uncertain climatic optima under climate change, the problems for weed science have become multi-faceted. To handle these complex weed problems, a holistic line of action with multi-disciplinary approaches is required, including adjustments to technology, management practices, and legislation. Improved knowledge of weed ecology, biology, genetics, and molecular biology is essential for developing sustainable weed control practices. Additionally, judicious use of advanced technologies, such as site-specific weed management systems and decision support modeling, will play a significant role in reducing costs associated with weed control. Further, effective linkages between farmers and weed researchers will be necessary to facilitate the adoption of technological developments. To meet these challenges, priorities in research need to be determined and the education system for weed science needs to be reoriented. In respect of the latter imperative, closer collaboration between weed scientists and other disciplines can help in defining and solving the complex weed management challenges of the 21st century. This consensus will provide more versatile and diverse approaches to innovative teaching and training practices, which will be needed to prepare future weed science graduates who are capable of handling the anticipated challenges of weed science facing in contemporary agriculture. To build this capacity, mobilizing additional funding for both weed research and

  3. Weed Control in Maize-Cowpea Intercropping System Related to Environmental Resources Consumption

    Directory of Open Access Journals (Sweden)

    Hamdollah ESKANDARI

    2011-03-01

    Full Text Available A field experiment was carried out in Ramhormoz, Iran during the 2008-2009 growing season to investigate the effects of different planting pattern of intercropping on environmental resource consumption and weed biomass. A randomized complete block design (RCBD with three replications was employed to compare the treatments. Treatments included maize sole crop (M, cow pea sole crop (C, within row intercropping (I1, row intercropping (I2 and mix cropping (I3. The density of intercropping was according to replacement design (one maize replaced by three cow pea plants. The results showed that environmental resource consumption was significantly (P?0.05 affected by cropping system, where PAR interception, moisture and nutrients uptake were higher in intercropping systems compared to sole crop systems. Regarding to weed control, intercrops were more effective than sole crops and it was related to lower availability of environmental resources for weeds in intercropping systems.

  4. Evaluating the Competitive Ability of Different Common Bean Genotypes Against The Weeds

    Directory of Open Access Journals (Sweden)

    R Amini

    2014-12-01

    Full Text Available In order to investigate the effects of weeds interference on yield and yield components of different genotypes of common bean, an experiment was conducted as split plot based on randomized complete block design with three replications at Agricultural Research Station of Tabriz University, in 2011. The main plots were eight genotypes of different types of common bean including red bean, (cv. Gholi, Sayad, Derakhshan and Akhtar; pinto bean, (cv. Khomein and Sadri and white bean (cv. Shokufa and Pak and the sub-plots were two levels of weed including weed-free and weed-infested. Results indicated that the effect of bean genotype was significant on yield and yield components. The effect of weed treatment was significant on all traits of common bean, except 100-seeds weight. The pod number per plant of all common bean genotypes reduced significantly under weed-infested treatment. The interaction effect of weed treatment× genotype was significant on bean seed number per pod, grain and biological yield. Among the genotype, the cv. Gholi had the highest pod number per plant and the cultivars Gholi and Shokufa had the highest seed number per pod. The cultivars of Gholi and Khomein produced the highest and lowest seed yield, respectively in both weed-free and weed-infested treatment. The common bean genotype showed different competitive ability as the genotypes Gholi and Pak had the higher competitive ability against the weeds than other genotypes. Therefore by cultivating the bean genotypes with high competitive ability against the weeds, the yield loss of common bean could be reduced as well as the growth of weed species will be suppressed.

  5. What do farmers' weed control decisions imply about glyphosate resistance? Evidence from surveys of US corn fields.

    Science.gov (United States)

    Wechsler, Seth J; McFadden, Jonathan R; Smith, David J

    2018-05-01

    The first case of glyphosate-resistant weeds in the United States was documented in 1998, 2 years after the commercialization of genetically engineered herbicide-resistant (HR) corn and soybeans. Currently, over 15 glyphosate-resistant weed species affect US crop production areas. These weeds have the potential to reduce yields, increase costs, and lower farm profitability. The objective of our study is to develop a behavioral model of farmers' weed management decisions and use it to analyze weed resistance to glyphosate in US corn farms. On average, we find that weed control increased US corn yields by 3700 kg ha -1 (worth approximately $US 255 ha -1 ) in 2005 and 3500 kg ha -1 (worth approximately $US 575 ha -1 ) in 2010. If glyphosate resistant weeds were absent, glyphosate killed approximately 99% of weeds, on average, when applied at the label rate in HR production systems. Average control was dramatically lower in states where glyphosate resistance was widespread. We find that glyphosate resistance had a significant impact on weed control costs and corn yields of US farmers in 2005 and 2010. Published 2017. This article is a U.S. Government work and is in the public domain in the USA. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  6. Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

    Science.gov (United States)

    Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

    2016-04-01

    value of NEE (26 and 23 g C m-2). Regarding the annual balance, significant differences were found in NEE between both treatments. The weed cover treatment showed 1.6 times higher annual net C assimilation (-132 g C m-2) than the weed removal treatment (-83 g C m-2). These results highlight the importance of sustainable management practices in agriculture to strengthen the behavior of cropping systems as C sinks.

  7. Effect of Weed Management on Weeds and Grain Yield of Haricot ...

    African Journals Online (AJOL)

    Weeds are one of the major constraints limiting haricot bean productivity and production. Field experiments were conducted on the effect of weed managements on weeds and grain yield of haricot bean (Phaseolus Vulgaris L.) at Melkassa Agricultural Research Center from 2011 - 2013. The objective was to determine the ...

  8. Ecologically sustainable weed management

    DEFF Research Database (Denmark)

    Liebman, Matt; Baraibar, Bàrbara; Buckley, Yvonne

    2016-01-01

    Weed management is a critically important activity on both agricultural and non-agricultural lands, but it is faced with a daunting set of challenges: environmental damage caused by control practices, weed resistance to herbicides, accelerated rates of weed dispersal through global trade, and gre......Weed management is a critically important activity on both agricultural and non-agricultural lands, but it is faced with a daunting set of challenges: environmental damage caused by control practices, weed resistance to herbicides, accelerated rates of weed dispersal through global trade...... to influence learning, decision-making, and actions by farmers and land managers. We offer examples of how these impediments are being addressed in different parts of the world, but note that there is no clear formula for determining which sets of policies, market mechanisms, and educational activities...... will be effective in various locations. Implementing new approaches for weed management will require multidisciplinary teams comprised of scientists, engineers, economists, sociologists, educators, farmers, land managers, industry personnel, policy makers, and others willing to focus on weeds within whole farming...

  9. Effect of long-term fertilisation on the weed community of a winter wheat field.

    Science.gov (United States)

    Jiang, Min; Liu, Tao; Huang, Niansheng; Shen, Xinping; Shen, Mingxing; Dai, Qigen

    2018-03-05

    Effects of fertilisation and other management techniques on a weed community were evaluated during wheat growth in a rice-wheat cropping system. Fertiliser treatments were C0 (C means chemical, C0 means zero chemical fertiliser.), CN (N fertiliser), CNK (N plus K fertiliser), CNPK (N plus P and K fertiliser), CNP (N plus P fertiliser), and CPK (P plus K fertiliser). Weed density, biomass, and bio-diversity were determined. Redundancy analysis (RDA) was used to investigate the relationship between fertiliser management, weed species, and weed density. The overall weed densities in the C0 and CPK treatments were the greatest during wheat seeding and ripening periods and were significantly greater than densities in the other treatments. N, P and organic matter in soil were highly correlated with weed species and density, whereas K in soil was not significantly correlated with weed species and weed density. N fertiliser significantly reduced weed density. Balanced fertilisation maintained weed species richness and resulting in a high yield of wheat. CNPK application reduced weed damage and improved the productivity and stability of the farmland ecosystem.

  10. Chemical Weed Control in Saffron (Crocus sativus Fields

    Directory of Open Access Journals (Sweden)

    majid abbaspoor

    2018-01-01

    (Othello® at dose of l.6 l ha-1, metribuzin (Sencore® at dose of 750 g ha-1 (applied after saffron harvest in autumn as pre emergence of weeds, triasulfuron + dicamba (Lintur® at dose of 165 g ha-1, atrazine (Gesaprim® at dose of 1000 g ha-1, Bensulfuron methyl (Londax® at dose of 50 g ha-1, bromoxinyl + MCPA (Bromicide® at dose of l.5 l ha-1, 2, 4-D + MCPA (U-46 combi fluid ® at dose of l.5 l ha-1, nicosulfuron (Cruz® at dose of l.5 l ha-1, haloxyfop methyl (Gallant super® at dose of l l ha-1, bentazon (Basagran® at dose of 3 l ha-1, tribenuron methyl (Granstar® at dose of 20 g ha-1 plus weed free and weedy checks. Herbicides were sprayed at early stage of weed growth (2-3 leafy stage (except for metribuzin which sprayed soon after flower harvest in autumn and pre emergence of weeds with Matabi® rechargeable sprayer calibrated to deliver 330 l ha-1. Four weeks after spraying, density and dry matter of dominant weed species were measured. At harvest, flower number, flower fresh weight and dry matter of 50 stigmas were measured. Data were analysed by SAS (9.2 software and mean were grouped by Duncan multiple range test (alpha=0.05. Results and Discussion Density and dry matter of dominant weed species i.e. Cirsium arvense, Acroptilon repense and Poa trivialis were significantly decreased by herbicide treatments when measured four weeks after spraying. Significant decrease in flower number and/or flower fresh weight of saffron occurred when sprayed with sulfosulfuron, nicosulfuron, 2, 4-D + MCPA, metsulfuron-methyl + sulfosulfuron, tribenuron methyl, mesosulfuron + idosulfuron + diflufenican and bromoxinyl + MCPA. Furtheremore, these herbicides can not be used for weed control in saffron. Metribuzin, oxadiazon, bentazon, haloxyfop methyl, oxyflurofen, bensulfuron methyl, triasulfuron + dicamba and atrazine caused no significant decrease in flower number and/or flower fresh weight of saffron and then can be recommended to use for weed control in saffron fields. In

  11. EFFECT OF SETTING THE PARAMETERS OF FLAME WEEDER ON WEED CONTROL EFFECTIVENESS

    Directory of Open Access Journals (Sweden)

    Miroslav Mojžiš

    2013-12-01

    Full Text Available Unconventional ways of growing plants, when we return to non-chemical methods of controlling weeds, require new weed control methods. One of the few physical methods, which found wider application in practice, is a flame weeder with heat burners based on the use of gas (LPG. However, the process of practical use of this flame weeder has a number of factors that positively or negatively affect the effectiveness of weed control. A precise setting of flame weeders is influenced, for example by weed species, weed growth stage, weather, type of crop grown, but also heat transmission and heat absorption by plant. Many variables that enter into the process must be eliminated for their negative impacts on achieving the best results in fighting against weeds. In this paper, we have focused on naming these parameters, on field trials that confirm the justification of the precise setting of parameters, and recommendations for practice to achieve a higher efficiency of thermal weed control.

  12. Fuels planning: science synthesis and integration; environmental consequences fact sheet 07: fire and weeds

    Science.gov (United States)

    Steve Sutherland

    2004-01-01

    Weed infestations cause an economic loss of $13 billion per year even though $9.5 billion per year is spent on weed control measures. In addition to these economic costs, weeds are replacing native species, altering native plant and animal communities, affecting ecosystem health and function, threatening biodiversity and Threatened, Endangered, and Sensitive (TES)...

  13. Effect of Doses of Oxyfluorfen and Trifluralin Hebicides on Weeds Control and Yields of Garlic Var. Mazand (Allium sativum L.

    Directory of Open Access Journals (Sweden)

    S. Mahzari

    2014-05-01

    Full Text Available To evaluate the effects of different doses of oxyfluorfen and trifluralin herbicides on weeds control, economic and biologic yield of garlic var. Mazand (Allium sativum L.. An experiment was conducted in the form of simple randomized complete block design with three replications in 2012 - 2013 year. Factor studied were: one application of trifluralin and oxyfluorfen 1.5, 2 and 2.5 lit.ha-1, two applications of oxyfluorfen 1.5 lit.ha-1, hand weeding control and without weeding control.Results showed that using different doses of herbicides significantly affected density and biomass of weeds. Two applicarions of oxyfluorfen with 1.5 liters per hectare and hand weeding were best options to reduce of weeds biomass. Using of oxyfluorfen herbicide (2 and 2.5 liters resulted in little damage and low stable on garlic. Using of different herbicides with different doses were significant on plant height, number of cloves per bulb, 100 seed weight, biological and economical yield and harvest index. Lowest economic yield was due to control treatment (540 g.m-2 and highest was obtained by using 1.5 liter of oxyfluorfen herbicide (1661.67 g.m-2, hand weeding (1686.67 g.m-2 and split oxyfluorfen application (1670 g.m-2. Finally, oxyfluorfen treatment (1.5 liter on 3 to 4 weeds leaf, were identified as the most appropriate treatments.

  14. Weed clearance in Hudiara Nallah by chemical weed control

    International Nuclear Information System (INIS)

    Dhillon, G.S.

    1981-01-01

    Hudiara Nallah is a flood stream in West Punjab. It has a length of about 45km and breadth of nearly 25 metres. About 20 subsidiary drains join with the Nallah. These drains have a length of about 270km. The Nallah has a discharge capacity of 1248 cusecs. Most of the subsidiary drains start from ponds which are generally infected with Eichhornia plants. These plants enter into the subsidiary drains and finally into Hudiara Nallah. The plants float freely on the surface of water and multiply at a high rate. One plant of the weed propagates to 24 plants in a period of one month. The plants thus cover the whole drain in a few months. The weed also originates from seeds. Their heavy growth forms a mat-like surface. The weeds also choke bridges and sometimes cause damage to their structures. These obstruct the flow of water and decrease the carrying capacity of the drain. Their infestation thus causes floods and the very purpose of the drains gets lost. Thus the Nallah is heavily infested with Eichhornia crassipes (water hyacinth weed). Due to its fast propagation and heavy infestation it was not possible to clear the weed manually. The problem was, therefore, referred to the Chemistry Division of the Irrigation and Power Research Institute, Amritsar, by the Drainage Circle of the Irrigation Department in June 1978 when weed propagation was in full swing. A chemical treatment method of eradication was attempted

  15. Linking Farmer Weed Management Behavior with Weed Pressure: More than Just Technology

    NARCIS (Netherlands)

    Riemens, M.M.; Groeneveld, R.M.W.; Kropff, M.J.; Lotz, L.A.P.; Renes, R.J.; Sukkel, W.; Weide, van der R.Y.

    2010-01-01

    Most studies on weed population dynamics in farming systems have focused on the effects of different weed control strategies. Those studies usually assume that farmers, operating within a particular system, have a uniform management style. However, it is likely that weed management decision making

  16. WEED INTERFERENCE IN EGGPLANT CROPS

    Directory of Open Access Journals (Sweden)

    LUIZ JUNIOR PEREIRA MARQUES

    2017-01-01

    Full Text Available Uncontrolled weed growth interferes with the growth eggplants and crop yields. To control weeds, the main weed species must be identified in crop growing areas and during weed control periods, as weed species might vary in relation to management practices. Therefore, this study aimed to identify the main weed species and determine the periods of weed interference in the eggplant cultivar Nápoli when grown under certain cultural practices, including plant staking and sprout thinning. The experiment was carried out in 2014 using a randomized complete block design, with 3 replications. The treatments consisted of 11 periods of (1 increasing weed control and (2 increasing coexistence of eggplant with weeds from the first day of transplanting (0-14, 0-28, 0-42, 0-56, 0-70, 0-84, 0-98, 0-112, 0-126, 0-140, and up do day 154. Eggplant staking and sprout thinning were performed 42 days after transplanting (DAT. Weed identification and crop yield assessments were performed to determine the Period Before Interference (PBI, Total Period of Interference Prevention (TPIP, and the Critical Period of Interference Prevention (CPIP. The major weeds found in the eggplant cultivar Nápoli were Eleusine indica, Portulaca oleracea, and Cyperus rotundus. Coexistence between the weed community and the eggplant throughout the entire crop production cycle reduced eggplant fruit yield by 78%. The PBI was 29 DAT and the TPIP was 48 DAT, resulting in 19 days of CPIP.

  17. Effect of weed management on weeds and grain yield of haricot bean

    African Journals Online (AJOL)

    Weeds are one of the major constraints limiting haricot bean productivity and production. Field experiments were conducted on the effect of weed managements on weeds and grain yield of haricot bean (Phaseolus Vulgaris L.) at Melkassa Agricultural Research Center from 2011 - 2013. The objective was to determine the ...

  18. The impact of stubble crop on spring barley weed infestation

    Directory of Open Access Journals (Sweden)

    Eleonora Wrzesińska

    2016-09-01

    Full Text Available The condition and degree of weed infestation were determined in a spring barely crop grown in a short-term monoculture after mulching the soil with plants grown as a stubble crop (the control treatment without cover crop – lacy phacelia, white mustard, sunflower. The field experiment was carried out in 2010–2013 on good rye soil complex using a split-block design in four replications. The obtained results (the mean from all years of the experiment showed that the stubble crop, especially sunflower, reduced the diversity of weed species without causing at the same time changes in weed species dominance. In all the control treatments of the experiment, Chenopodium album and Fallopia convolvulus were the dominant species. The degree of spring barley weed infestation depended on the species grown in the cover crop. White mustard and lacy phacelia slightly increased the number of weeds but their fresh matter significantly increased. However, the sunflower cover crop significantly increased the number of weeds without any substantial differentiation of their fresh mass.

  19. INTEGRATED WEED CONTROL IN MAIZE.

    Science.gov (United States)

    Latré, J; Dewitte, K; Derycke, V; De Roo, B; Haesaert, G

    2015-01-01

    Integrated pest management has been implemented as a general practice by EU legislation. As weed control actually is the most important crop protection measure in maize for Western Europe, the new legislation will have its impact. The question is of course which systems can be successfully implemented in practice with respect to labour efficiency and economical parameters. During 3 successive growing seasons (2007, 2008, 2009) weed control in maize was evaluated, the main focus was put on different techniques of integrated weed control and was compared with chemical weed control. Additionally, during 4 successive growing seasons (2011, 2012, 2013 and 2014) two objects based on integrated weed control and two objects based on mechanical weed control were compared to about twenty different objects of conventional chemical weed control. One of the objects based on mechanical weed control consisted of treatment with the flex-tine harrow before and after emergence in combination with chemical weed control at a reduced rate in 3-4 leave stage. The second one consisted of broadcast mechanical treatments before and after emergence followed by a final in-row application of herbicides and an inter-row cultivation at 6-7(8) leave stage. All trials were conducted on the Experimental farm of Bottelare HoGent-UGent on a sandy loam soil. Maize was growing in 1/3 crop rotation. The effect on weed growth as well as the economic impact of the different applications was evaluated. Combining chemical and mechanical weed control is a possible option in conventional farming but the disadvantages must be taken into account. A better planned weed control based on the real present weed-population in combination with a carefully thought-out choice of herbicides should also be considered as an IPM--approach.

  20. Weed ecology and population dynamics

    Science.gov (United States)

    A global rise in herbicide resistant weed genotypes, coupled with a growing demand for food produced with minimal external synthetic inputs, is driving producer interest in reducing reliance on herbicides for weed management. An improved understanding of weed ecology can support the design of weed s...

  1. Effect of tillage system on yield and weed populations of soybean ( Glycin Max L.).

    Science.gov (United States)

    Hosseini, Seyed Z; Firouzi, Saeed; Aminpanah, Hashem; Sadeghnejhad, Hamid R

    2016-03-01

    Field experiment was conducted at Agricultural and Natural Resources Research Center of Golestan Province, Iran, to determine the effects of tillage system and weed management regime on yield and weed populations in soybean ( Glycin max L.). The experimental design was a split plot where the whole plot portion was a randomized complete block with three replicates. Main plots were tillage system: 1- No-till row crop seeding, 2- No-till seed drilling, 3- Tillage with disc harrow and drill planting, 4- Tillage with chisel packer and drill planting. The subplots were weed management regimes: 1-Weed control with herbicide application, 2- Hand weeding, 3- Herbicide application plus hand weeding, and 4- Non-weeding. Results indicated that the main effects of tillage system and weed management regime were significant for seed yield, pod number per plant, seed number per pod, weed density and biomass, while their interaction were significant only for weed density, weed biomass, and seed number per pod. The highest grain yields (3838 kg ha-1) were recorded for No-till row crop seeding. The highest seed yield (3877 kg ha-1) also was recorded for weed control with herbicide and hand weeding treatment, followed by hand weeding (3379 kg ha-1).

  2. Ecologically sustainable weed management

    NARCIS (Netherlands)

    Liebman, Matt; Baraibar, Bàrbara; Buckley, Yvonne; Childs, Dylan; Christensen, Svend; Cousens, Roger; Eizenberg, Hanan; Heijting, Sanne; Loddo, Donato; Merotto, Aldo; Renton, Michael; Riemens, Marleen

    2016-01-01

    Weed management is a critically important activity on both agricultural and non-agricultural lands, but it is faced with a daunting set of challenges: environmental damage caused by control practices, weed resistance to herbicides, accelerated rates of weed dispersal through global trade, and

  3. Weeds of onion fields and effects of some herbicides on weeds in ...

    African Journals Online (AJOL)

    Weeds are one of the most important problems in onion (Allium cepa L.) production areas, since onion plants are poor competitors. This study was conducted in order to identify the weed species in onion fields in Cukurova Region, establish the effects of some herbicides on weeds and the yield of onion in reducing the ...

  4. Weed species diversity in organic and integrated farming systems

    Directory of Open Access Journals (Sweden)

    Magdalena Jastrzębska

    2013-10-01

    Full Text Available Phytosociological data were collected in 1994–1996 in plots (relevés at the Research Station for Organic Farming and Conservation Breeding of the Polish Academy of Sciences in Popielno included in a large-area experiment conducted according to the concept and method proposed by Prof. S. Nawrocki. In a four-field crop rotation (root crops – spring barley undersown with red clover and grasses – red clover/grass mixture – winter triticale, each field was divided into two management units, organic and integrated. Data were collected in relevés by the Braun-Blanquet method, each year at the peak of the growing season. Weed abundance (% cover in cultivated fields and the number of weed species (species richness in crops were determined, which provided a basis for calculating the Shannon-Wiener indices of species diversity and evenness, and the Rényi profiles. The qualitative (species and quantitative structure of weed communities was compared using the Sørensen index. A total of 115 weed taxa (species, subspecies and varieties were identified in the examined agro-phytocenoses. Echinochloa crus-galli, Chenopodium album, Matricaria maritima subsp. inodora, Capsella bursa-pastoris, Thlaspi arvense and Stellaria media were the most abundant. Weed infestation was slightly higher in the organic farming system than in the integrated system. Organic farming contributed to higher weed species diversity in root crops, red clover/grass mixtures and winter triticale. Weed species richness was reduced in red clover/grass stands, while root crops and – to a lesser degree – spring barley undersown with red clover and grasses decreased weed species diversity. The species composition and in particular the quantitative structure of weeds were affected by crop species and cultivation regime rather than by the farming system. Weed communities of crops grown under organic and integrated farming systems were more similar with regard to species composition

  5. Evaluation of Selected Pre-Emergence Herbicides for Weed Control ...

    African Journals Online (AJOL)

    Pendimentalin had no significant effect on the plantlets across the rates tested. The best weed control was achieved with diuron applied at 25% and above, while the least weed control occurred on the control plot and these treated with 10% of atrazine and primextra Gold. However, there were no significant variations in the ...

  6. Benchmark study on glyphosate-resistant cropping systems in the United States. Part 7: Effects of weed management strategy (grower practices versus academic recommendations) on the weed soil seedbank over 6 years.

    Science.gov (United States)

    Gibson, David J; Young, Bryan G; Owen, Micheal D K; Gage, Karla L; Matthews, Joseph L; Jordan, David L; Shaw, David R; Weller, Stephen C; Wilson, Robert G

    2016-04-01

    Shifts in weed species composition and richness resulting from near-exclusive reliance on herbicides in glyphosate-resistant (GR) cropping systems has necessitated the implementation of alternative weed management tactics to reduce selection pressures of herbicides. We contrasted the response of the weed soil seedbank to effects of weed management strategy, comparing grower practices with academic recommendations for best management practices (BMPs) over 6 years and across five weed hardiness zones in the US Midwest at sites subject to GR cropping systems. Total weed population density and species richness varied according to cropping system, location and prior year's crop, but less so to weed management strategy. The seedbank population density for 11 of the 14 most frequent weed species was affected by weed management strategy either alone or in an interaction with hardiness zone or year, or both. In only 29% of comparisons was weed population density lower following academic recommendations, and this depended upon prior crop and cropping system. The population density of high-risk weed species was reduced by academic recommendations, but only in two of six years and under continuous GR maize. Overall, the weed population density was decreasing in field halves subject to the BMPs in the academic recommendations relative to grower practices. The soil seedbank is slow to respond to academic recommendations to mitigate glyphosate-resistant weeds, but represents a biological legacy that growers need to keep in mind even when management practices reduce emerged field weed population densities. © 2015 Society of Chemical Industry.

  7. WEED SURVEYING OF PHACELIA (PHACELIA TANACETIFOLIA L.) AND EVALUATING THE EFFICIENCY OF THE WEED CONTROL.

    Science.gov (United States)

    Horváth, E; Szabó, R

    2014-01-01

    The experiment was set up in an area of 9 ha that was split into 4 plots: in plot 1 the row spacing was 12 cm and the seeding rate was 10 kg; in plot 2 the row spacing was 24 cm and the seeding rate was 10 kg; in plot 3 the row spacing was 24 cm and the seeding rate was 8 kg; in plot 4 the row spacing was 12 cm and the seeding rate was 8 kg. After the weed surveying, the total weed coverage was established as follows: in plot 1 the total weed coverage was 11.34%, in plot 2 it was 12.3%, in plot 3 it was 18%, and in plot 4 the total weed coverage was 15%. Based on the weed survey, on the test area the following dicotyledon weeds belonging to the T4 Raunkiaer plant life-form category occupied the highest percentage: heal-all, black-bindweed, goosefoot. The proportion of the perennial dicotyledons: field bindweed (G3), tuberous pea (G1), white campion (H3) was negligible. In all four cases the weed control was executed using the same herbicide in the same doses and with regard to the weed species it showed the same level of efficiency. The smaller row spacing and higher seeding rate has a beneficial effect on the weed suppressing capacity of the crop, the crop's weed suppressing capacity is better and the development of the weeds becomes worse.

  8. Ecological Intensification Through Pesticide Reduction: Weed Control, Weed Biodiversity and Sustainability in Arable Farming.

    Science.gov (United States)

    Petit, Sandrine; Munier-Jolain, Nicolas; Bretagnolle, Vincent; Bockstaller, Christian; Gaba, Sabrina; Cordeau, Stéphane; Lechenet, Martin; Mézière, Delphine; Colbach, Nathalie

    2015-11-01

    Amongst the biodiversity components of agriculture, weeds are an interesting model for exploring management options relying on the principle of ecological intensification in arable farming. Weeds can cause severe crop yield losses, contribute to farmland functional biodiversity and are strongly associated with the generic issue of pesticide use. In this paper, we address the impacts of herbicide reduction following a causal framework starting with herbicide reduction and triggering changes in (i) the management options required to control weeds, (ii) the weed communities and functions they provide and (iii) the overall performance and sustainability of the implemented land management options. The three components of this framework were analysed in a multidisciplinary project that was conducted on 55 experimental and farmer's fields that included conventional, integrated and organic cropping systems. Our results indicate that the reduction of herbicide use is not antagonistic with crop production, provided that alternative practices are put into place. Herbicide reduction and associated land management modified the composition of in-field weed communities and thus the functions of weeds related to biodiversity and production. Through a long-term simulation of weed communities based on alternative (?) cropping systems, some specific management pathways were identified that delivered high biodiversity gains and limited the negative impacts of weeds on crop production. Finally, the multi-criteria assessment of the environmental, economic and societal sustainability of the 55 systems suggests that integrated weed management systems fared better than their conventional and organic counterparts. These outcomes suggest that sustainable management could possibly be achieved through changes in weed management, along a pathway starting with herbicide reduction.

  9. [Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake].

    Science.gov (United States)

    Jiang, Qiqing; Tang, Jianjun; Chen, Xin; Chen, Jing; Yang, Ruyi; Hu, S

    2005-05-01

    In this paper, a greenhouse experiment was conducted to study the responses of different functional groups weeds to simulated nitrogen deposition (4.0 g N.m(-2).yr(-1)). Native weed species Poa annua, Lolium perenne, Avena fatua, Medicago lupulina, Trifolium repens, Plantago virginica, Veronica didyma, Echinochloa crusgalli var. mitis, Eleusine indica and Amaranthus spinosus in orchard ecosystem were used test materials, and their above-and underground biomass and nitrogen uptake were measured. The results showed that under simulated N deposition, the total biomass, shoot biomass and root biomass of all weed species tended increase, while the total biomass was differed for different functional groups of weeds. The biomass of C4 grass, legumes and C3 grass was significantly increased under N deposition, while that of C3 and C4 forbs was not significantly impacted. The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition, but that of Poa annu, Lolium perenne, Medicago lupulina, Trifolium repens and Amarathus spinosus was not impacted significantly. N deposition had no significant effect on plant N concentration, but significantly enhanced the N uptake of all test weed species except Amarathus spinosus, Poa annua and Veronica didyma. was suggested that the further increase of N deposition might speed up the changes of the community structure weed species due to their different responses to N deposition.

  10. Weed Dynamics and Management in Wheat

    DEFF Research Database (Denmark)

    Jabran, Khawar; Mahmood, Khalid; Melander, Bo

    2017-01-01

    ) chemical weed control; and (vi) integrated weed management strategy in wheat. A critical analysis of recent literature indicated that broadleaved weeds are the most common group of weeds in wheat fields followed by grass weeds, while sedges were rarely noted in wheat fields. Across the globe, the most...

  11. Selective weed control using laser techniques

    OpenAIRE

    Marx, Christian; Pastrana-Perez, Julio; Hustedt, Michael; Barcikowski, Stephan; Haferkamp, Heinz; Rath, Thomas

    2012-01-01

    This contribution discusses technical and growth relevant aspects of using laser techniques for weed control. The research on thermal weed control via laser first focused on the interaction of laser beams and weed plants. Due to preliminary studies, a CO2-laser was selected for further studies with regard to the process factors laser energy, laser spot area, coverage of the weeds meristem, weed species (Amaranthus retroflexus), and weed growth stage. Thereby, the laser damage was modeled in o...

  12. Analysis of Traits Related to Weed Competitiveness in Sweet Corn (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Natalia de Leon

    2012-03-01

    Full Text Available Weed management in sweet corn can be costly; genetic improvements in sweet corn competitiveness may reduce this expense. Competitive ability can exist as weed suppressive ability (WSA, or crop tolerance (CT. Previous studies in corn have found year of hybrid release, maturity, plant height, leaf angle and leafiness may affect WSA, while hybrid era, maturity, and plant height may affect CT. However, many of these studies were limited to very few genotypes. The objective of this study was to assess the effects of phenomorphological traits on sweet corn competitiveness and the inheritance of these traits. An incomplete half-diallel from seven historic sweet corn inbred lines of varying morphologies was evaluated in a split-block randomized complete block design in three environments. Forage sorghum was interplanted in half of the blocks to act as a model weed. Significant differences among hybrids were generally found for both phenomorphological traits and traits measuring WSA and CT, such as sorghum biomass and yield stability, respectively. Crop plant height was most predictive of WSA and CT. In this set of genotypes, competitive ability may be passed with reasonable fidelity from parent to offspring, suggesting that sweet corn could be bred for competitive ability.

  13. Assessing the impact of revegetation and weed control on urban sensitive bird species.

    Science.gov (United States)

    Archibald, Carla L; McKinney, Matthew; Mustin, Karen; Shanahan, Danielle F; Possingham, Hugh P

    2017-06-01

    Nature in cities is concentrated in urban green spaces, which are key areas for urban biodiversity and also important areas to connect people with nature. To conserve urban biodiversity within these natural refugia, habitat restoration such as weed control and revegetation is often implemented. These actions are expected to benefit biodiversity, although species known to be affected by urbanization may not be interacting with restoration in the ways we anticipate. In this study, we use a case study to explore how urban restoration activities impact different bird species. Birds were grouped into urban sensitivity categories and species abundance, and richness was then calculated using a hierarchical species community model for individual species responses, with "urban class" used as the hierarchical parameter. We highlight variable responses of birds to revegetation and weed control based on their level of urban sensitivity. Revegetation of open grassy areas delivers significant bird conservation outcomes, but the effects of weed control are neutral or in some cases negative. Specifically, the species most reliant on remnant vegetation in cities seem to remain stable or decline in abundance in areas with weed control, which we suspect is the result of a simplification of the understorey. The literature reports mixed benefits of weed control between taxa and between locations. We recommend, in our case study site, that weed control be implemented in concert with replanting of native vegetation to provide the understory structure preferred by urban sensitive birds. Understanding the impacts of revegetation and weed control on different bird species is important information for practitioners to make restoration decisions about the allocation of funds for conservation action. This new knowledge can be used both for threatened species and invasive species management.

  14. Weed hosts of cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Vennila, S; Prasad, Y G; Prabhakar, M; Agarwal, Meenu; Sreedevi, G; Bambawale, O M

    2013-03-01

    The exotic cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) invaded India during 2006, and caused widespread infestation across all nine cotton growing states. P. solenopsis also infested weeds that aided its faster spread and increased severity across cotton fields. Two year survey carried out to document host plants of P. solenopsis between 2008 and 2010 revealed 27, 83, 59 and 108 weeds belonging to 8, 18, 10 and 32 families serving as alternate hosts at North, Central, South and All India cotton growing zones, respectively. Plant species of four families viz., Asteraceae, Amaranthaceae, Malvaceae and Lamiaceae constituted almost 50% of the weed hosts. While 39 weed species supported P. solenopsis multiplication during the cotton season, 37 were hosts during off season. Higher number of weeds as off season hosts (17) outnumbering cotton season (13) at Central over other zones indicated the strong carryover of the pest aided by weeds between two cotton seasons. Six, two and seven weed hosts had the extreme severity of Grade 4 during cotton, off and cotton + off seasons, respectively. Higher number of weed hosts of P. solenopsis were located at roadside: South (12) > Central (8) > North (3) zones. Commonality of weed hosts was higher between C+S zones, while no weed host was common between N+S zones. Paper furnishes the wide range of weed hosts of P. solenopsis, discusses their significance, and formulated general and specific cultural management strategies for nationwide implementation to prevent its outbreaks.

  15. Weed Control in Soybean (Glycine max)

    International Nuclear Information System (INIS)

    Kipkemoi, P.L.

    2002-01-01

    Weed Compete for limited growth factors with crop plants. This result in loss of crop vigour and hence reduces crop yields. A study was conducted in 1997 and 2001 to evaluate the use of herbicides and hand hoeing for weed control in soybeans. Crop establishment was by hand planting. The herbicides were applied using CP3 Knap sack sprayer calibrated to deliver a spray volume of 150l/ha. Hand weeding treatment were done as appropriate. The trial layout was randomised complete block design with four replications in both years. The tested herbicides did not satisfactorily control the weeds present at the experimental site in both years. Hand weeding on the other hand gave good control of the weeds which were reflected in high soybean yields. In these trials yields were negatively correlated with the number of weeds present. The tested herbicides alone appeared to be inadequate in controlling weeds in soybean. Compared with the weed-free treatment a single application of soil-applied or post-emergence herbicides did not control a broad spectrum of weeds and reduced soybean yields. It can also be inferred that soybean yield losses are minimised if they are kept weed free for at most 6 weeks after emergence

  16. MAINTAINING LONG-TERM MANAGEMENT: Herbicide-resistant weeds challenge some signature cropping systems

    Directory of Open Access Journals (Sweden)

    Bradley D. Hanson

    2014-10-01

    Full Text Available Invasive and endemic weeds pose recurring challenges for California land managers. The evolution of herbicide resistance in several species has imposed new challenges in some cropping systems, and these issues are being addressed by UC Cooperative Extension farm advisors, specialists and faculty. There are currently 24 unique herbicide-resistant weed biotypes in the state, dominated by grasses and sedges in flooded rice systems and, more recently, glyphosate-resistant broadleaf and grass weeds in tree and vine systems, roadsides and glyphosate-tolerant field crops. Weed scientists address these complex issues using approaches ranging from basic physiology and genetics research to applied research and extension efforts in grower fields throughout the state. Although solutions to herbicide resistance are not simple and are affected by many biological, economic, regulatory and social factors, California stakeholders need information, training and solutions to address new weed management problems as they arise. Coordinated efforts conducted under the Endemic and Invasive Pests and Disease Strategic Initiative directly address weed management challenges in California's agricultural industries.

  17. Ecological weed management by cover cropping : effects on weed growth in autumn and weed establishment in spring

    NARCIS (Netherlands)

    Kruidhof, H.M.; Bastiaans, L.; Kropff, M.J.

    2008-01-01

    Cover crops grown in the period between two main crops have potential as an important component of a system-oriented ecological weed management strategy. In late summer and autumn, the cover crop can suppress growth and seed production of weeds, whereas the incorporation of cover crop residues in

  18. Allelopatic potential of weeds under the minimalization of soil treatment

    Directory of Open Access Journals (Sweden)

    Mikhail A. Mazirov

    2014-01-01

    Full Text Available The content of water-dispersible phenol substances in rhizosphere both of annual and perennial species of weeds (Cirsium arvense, Sonchus arvensis increases under soil treatment minimalization. The higher content of phenol substances of researched weeds is defined in rhizosphere of Common Couch (Agropyrum repens. The absence of intensive anthropogenic treatment of plowing layer which accumulates the significant mass of weed’s roots in the cause of much more higher allelopathic potential of some species’ of weeds. The high level of saturation by weeds in agrophytocoenosis under non-tillage soil treatment is defines the competitiveness between certain sepsis’ of weeds, especially, at the beginning of the vegetation. In this case, increasing the secretion of phenol substances is one of the physiological screenings of such competitiveness.

  19. Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions

    DEFF Research Database (Denmark)

    Johansen, Anders; Bangsø Nielsen, Henrik; Hansen, Christian M.

    2013-01-01

    did not affect egg survival during the first 48h and it took up to 10days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites......, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (55°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55°C...

  20. Winter Annual Weed Response to Nitrogen Sources and Application Timings prior to a Burndown Corn Herbicide

    Directory of Open Access Journals (Sweden)

    Kelly A. Nelson

    2015-01-01

    Full Text Available Autumn and early preplant N applications, sources, and placement may affect winter annual weed growth. Field research evaluated (1 the effect of different nitrogen sources in autumn and early preplant on total winter annual weed growth (2006–2010, and (2 strip-till and broadcast no-till N applied in autumn and early preplant on henbit (Lamium amplexicaule L. growth (2008–2010 prior to a burndown herbicide application. Total winter annual weed biomass was greater than the nontreated control when applying certain N sources in autumn or early preplant for no-till corn. Anhydrous ammonia had the lowest average weed density (95 weeds m−2, though results were inconsistent over the years. Winter annual weed biomass was lowest (43 g m−2 when applying 32% urea ammonium nitrate in autumn and was similar to applying anhydrous ammonia in autumn or early preplant and the nontreated control. Henbit biomass was 28% greater when applying N in the autumn compared to an early preplant application timing. Nitrogen placement along with associated tillage with strip-till placement was important in reducing henbit biomass. Nitrogen source selection, application timing, and placement affected the impact of N on winter annual weed growth and should be considered when recommending a burndown herbicide application timing.

  1. Weed seed inactivation in soil mesocosms via biosolarization with mature compost and tomato processing waste amendments.

    Science.gov (United States)

    Achmon, Yigal; Fernández-Bayo, Jesús D; Hernandez, Katie; McCurry, Dlinka G; Harrold, Duff R; Su, Joey; Dahlquist-Willard, Ruth M; Stapleton, James J; VanderGheynst, Jean S; Simmons, Christopher W

    2017-05-01

    Biosolarization is a fumigation alternative that combines passive solar heating with amendment-driven soil microbial activity to temporarily create antagonistic soil conditions, such as elevated temperature and acidity, that can inactivate weed seeds and other pest propagules. The aim of this study was to use a mesocosm-based field trial to assess soil heating, pH, volatile fatty acid accumulation and weed seed inactivation during biosolarization. Biosolarization for 8 days using 2% mature green waste compost and 2 or 5% tomato processing residues in the soil resulted in accumulation of volatile fatty acids in the soil, particularly acetic acid, and >95% inactivation of Brassica nigra and Solanum nigrum seeds. Inactivation kinetics data showed that near complete weed seed inactivation in soil was achieved within the first 5 days of biosolarization. This was significantly greater than the inactivation achieved in control soils that were solar heated without amendment or were amended but not solar heated. The composition and concentration of organic matter amendments in soil significantly affected volatile fatty acid accumulation at various soil depths during biosolarization. Combining solar heating with organic matter amendment resulted in accelerated weed seed inactivation compared with either approach alone. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  2. Weed control based on real time patchy application of herbicides using image analysis as a non-destructive estimation method for weed infestation and herbicide effects

    DEFF Research Database (Denmark)

    Asif, Ali

    There is an increasing concern about excessive use of herbicides for weed control in arable lands. Usually the whole field is sprayed uniformly, while the distribution of weeds often is non-uniform. Often there are spots in a field where weed pressure is very low and has no significant effect...... on crop yield. The excessive use of spraying can potentially be reduced by spraying only those parts of the field where it has economic importance. The competition relation between weeds and crop was ana-lyzed in context of real time patch spray. A non-destructive image analysis method was developed...

  3. [Effect of tillage patterns on the structure of weed communities in oat fields in the cold and arid region of North China].

    Science.gov (United States)

    Zhang, Li; Zhang, Li; Wu, Dong-Xia; Zhang, Jun-Jun

    2014-06-01

    In order to clarify the effects of tillage patterns on farmland weed community structure and crop production characteristics, based on 10 years location experiment with no-tillage, subsoiling and conventional tillage in the cold and arid region of North China, and supplementary experiment of plowing after 10 years no-tillage and subsoiling, oat was planted in 2 soils under different tillage patterns, and field weed total density, dominant weed types, weed diversity index, field weed biomass and oats yield were measured. The results showed that the regional weed community was dominated by foxtail weed (Setaira viridis); the weed density under long-term no-tillage was 2.20-5.14 times of tillage at different growing stages of oat, but there were no significant differences between conditional tillage and plowing after long-term no-tillage and subsoiling. Field weed Shannon diversity indices were 0.429 and 0.531, respectively, for sandy chestnut soil and loamy meadow soil under no-tillage conditions, and field weed biomass values were 1.35 and 2.26 times of plowing treatment, while the oat biomass values were only 2807.4 kg x hm(-2) and 4053.9 kg x hm(-2), decreased by 22.3% and 46.2%, respectively. The results showed that the weed community characteristics were affected by both tillage patterns and soil types. Long-term no-tillage farmland in the cold and arid region of North China could promote the natural evolution of plant communities by keeping more perennial weeds, and the plowing pattern lowered the annual weed density, eliminated perennial weeds with shallow roots, and stimulated perennial weeds with deep roots.

  4. EFFECT OF SOWING DATE AND WEED CONTROL METHOD ON THE GROWTH AND YIELD OF SOYBEAN

    Directory of Open Access Journals (Sweden)

    Nasrin Akter

    2016-06-01

    Full Text Available Sowing date and weed management play a significant role in determining soybean growth, development and seed yield. Results showed that different sowing date and weed control methods had significant effect on relative weed density, weed biomass, weed control efficiency, plant height, dry weight plant-1 and seed yield of soybean. Among the infested weed species in the experimental field the dominant weeds were Lindernia procumbens (44.78%, Echinochloa colonum (26.39% and Cynodon dactylon (16.30%. The results also revealed that early sowing (2 January brought about the highest seed yield (2.17 t ha-1 and sowing delay (1 February resulted in the lowest yield (1.64 t ha-1. Two times hand weeding (20 and 40 DAS controlled the weeds most effectively and led to highest seed yield (2.23 t ha-1 which was statistically similar (2.19 t ha-1 with herbicide application. Combination effect showed that the highest seed yield (2.50 t ha-1 was obtained from 2 January sowing when the crop was weeded by hand at 20 and 40 DAS.

  5. Biological weed control with soil fungi? Antagonistic effects of arbuscular mycorrhizal fungi on the growth of weeds

    NARCIS (Netherlands)

    Veiga, R.

    2012-01-01

    Excessive weed growth represents one of the major threats to crop production especially when reliance on herbicides is reduced. Biological weed control is an alternative, environmentally-sound method that, combined with other weed control practices, can contribute to an effective weed management in

  6. Distinct germination response of endangered and common arable weeds to reduced water potential.

    Science.gov (United States)

    Rühl, A T; Eckstein, R L; Otte, A; Donath, T W

    2016-01-01

    Arable weeds are one of the most endangered species groups in Europe. Modern agriculture and intensive land-use management are the main causes of their dramatic decline. However, besides the changes in land use, climate change may further challenge the adaptability of arable weeds. Therefore, we investigated the response pattern of arable weeds to different water potential and temperature regimes during the phase of germination. We expected that endangered arable weeds would be more sensitive to differences in water availability and temperature than common arable weeds. To this end, we set up a climate chamber experiment where we exposed seeds of five familial pairs of common and endangered arable weed species to different temperatures (5/15, 10/20 °C) and water potentials (0.0 to -1.2 MPa). The results revealed a significant relationship between the reaction of arable weed species to water availability and their Red List status. The effects of reduced water availability on total germination, mean germination time and synchrony were significantly stronger in endangered than in common arable weeds. Therefore, global climate change may present a further threat to the survival of endangered arable weed species. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  7. Problems and achievements of cotton (Gossypium Hirsutum L. weeds control

    Directory of Open Access Journals (Sweden)

    T. Barakova

    2017-09-01

    Full Text Available Abstract. Weed control in the cultivation of cotton is critical to the yield and quality of production. The influence of economically important weeds was studied. Chemical control is the most effective method of weed control in cotton but much of the information on it relates to primary weed infestation. Problems with primary weed infestation in cotton have been solved to a significant extent. The question of secondary weed infestation with annual and perennial graminaceous weeds during the period of cotton vegetation is also determined largely by the use of antigraminaceous herbicides. The data related to herbicides to effectively control secondary germinated broadleaf weeds in conventional technology for cotton growing are quite scarce, even globally. We are still seeking effective herbicides for control of these weeds in cotton crops. Studies on their influence on the sowing characteristics of cotton seed and the quality of cotton fiber are still insufficient. In the scientific literature there is not enough information on these questions. The combinations of herbicides, as well as their tank mixtures with fertilizers or plant growth regulators are more efficient than autonomous application. Often during their combined application higher synergistic effect on yield is produced. There is information about cotton cultivars resistant to glyphosate. These cultivars are GMO and they are banned within the European Union, including Bulgaria.

  8. [Spatial and temporal dynamics of the weed community in the Zoysia matrella lawn].

    Science.gov (United States)

    Liu, Jia-Qi; Li, You-Han; Zeng, Ying; Xie, Xin-Ming

    2014-02-01

    The heterogeneity of species composition is one of the main attributes in weed community dynamics. Based on species frequency and power law, this paper studied the variations of weed community species composition and spatial heterogeneity in a Zoysia matrella lawn in Guangzhou at different time. The results showed that there were 43 weed species belonging to 19 families in the Z. matrella lawn from 2007 to 2009, in which Gramineae, Compositae, Cyperaceae and Rubiaceae had a comparative advantage. Perennial weeds accounted for the largest proportion of weeds and increased gradually in the three years. Weed communities distributed in higher heterogeneity than in a random model. Dominant weeds varied with season and displayed regularity in the order of 'dicotyledon-monocotyledon-dicotyledon weeds' and 'perennial-annual-perennial weeds'. The spatial heterogeneity of weed community in Z. matrella lawn was higher in summer than in winter. The diversity and evenness of weed community were higher in summer and autumn than in winter and spring. The number of weed species with high heterogeneity in summer was higher than in the other seasons. The spatial heterogeneity and diversity of weed community had no significant change in the three years, while the evenness of weed community had the tendency to decline gradually.

  9. 7 CFR 201.15 - Weed seeds.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation or...

  10. Phytotoxicity of leaf aqueous extract of Rapanea umbellata (Mart. Mez (Primulaceae on weeds - doi: 10.4025/actasciagron.v35i2.16166

    Directory of Open Access Journals (Sweden)

    Paula Novaes

    2012-12-01

    Full Text Available Allelopathic substances can be used to develop weed control alternatives based on natural products. The objective of this study was to compare the phytotoxic activity of aqueous leaf extracts of Rapanea umbellata with the toxicity of a synthetic herbicide on the germination and growth of weed species. The weeds species barnyard grass (Echinochloa crus-galli, wild poinsettia (Euphorbia heterophylla and morning glory (Ipomoea grandifolia were used. The effects of the aqueous leaf extract of R. umbellata at concentrations of 10% and 5% (g mL-1 were compared to the control (distilled water and to the synthetic herbicide oxyfluorfen. The average weed germination time was significantly lower (p < 0.05 in control than in extract and herbicide treatments. The herbicide had more significant effects than the extract on the initial growth of the aerial part. However, the initial growth of the root part was significantly more affected by the leaf extract than by the herbicide. The extract also caused many disorders in weed root anatomy. Therefore, the leaf aqueous extract of R. umbellata showed important results that indicate that it should be bioprospected and that its allelochemicals should be purified for the discovery of natural-origin herbicides.

  11. Weed management: a case study from north-west Pakistan

    International Nuclear Information System (INIS)

    Marwat, K.B.; Hashim, S.; Ali, H.

    2010-01-01

    Alien and exotic plant invasions are threatening the floral diversity around the globe and affect ecological processes. Weed invasion has been documented in North-West Pakistan. A total of 16 weeds were reported as invasive. These were Xanthium strumarium, Ipomoea eriocarpa, Alternanthera pungens, Trianthema portulacastrum, Tagetes minuta, Imperata cylindrica, Amaranthus hybridus subsp. hybridus, Robinia pseudo-acacia, Broussonetia papyrifera, Ailanthus altissima, Pistia stratiotes, Phragmites australis, Parthenium hysterophorus, Cannabis sativa, Galium aparine and Emex spinosus. Among these Robinia pseudo-acacia, Broussonetia papyrifera and Ailanthus altissima are trees and were purposely introduced as they later became invasive. They were aggressive in nature and replaced or suppressed the local vegetation. Their distribution, history of invasion and management has been discussed here. The behaviour and association of the 36 problem weeds with different crops has also been outlined as they perspired from the farmers. (author)

  12. Weed management: a case study from north-west Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Marwat, K B; Hashim, S; Ali, H [KPK Agriculture University, Peshawar (Pakistan). Dept. of Weed Science

    2010-12-15

    Alien and exotic plant invasions are threatening the floral diversity around the globe and affect ecological processes. Weed invasion has been documented in North-West Pakistan. A total of 16 weeds were reported as invasive. These were Xanthium strumarium, Ipomoea eriocarpa, Alternanthera pungens, Trianthema portulacastrum, Tagetes minuta, Imperata cylindrica, Amaranthus hybridus subsp. hybridus, Robinia pseudo-acacia, Broussonetia papyrifera, Ailanthus altissima, Pistia stratiotes, Phragmites australis, Parthenium hysterophorus, Cannabis sativa, Galium aparine and Emex spinosus. Among these Robinia pseudo-acacia, Broussonetia papyrifera and Ailanthus altissima are trees and were purposely introduced as they later became invasive. They were aggressive in nature and replaced or suppressed the local vegetation. Their distribution, history of invasion and management has been discussed here. The behaviour and association of the 36 problem weeds with different crops has also been outlined as they perspired from the farmers. (author)

  13. RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean.

    Science.gov (United States)

    Horvath, David P; Hansen, Stephanie A; Moriles-Miller, Janet P; Pierik, Ronald; Yan, Changhui; Clay, David E; Scheffler, Brian; Clay, Sharon A

    2015-07-01

    Weeds reduce yield in soybeans (Glycine max) through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. RNASeq data were collected from six biological samples of soybeans growing with or without weeds. Weed species and the methods to maintain weed-free controls varied between years to mitigate treatment effects, and to allow detection of general soybean weed responses. Soybean plants were not visibly nutrient- or water-stressed. We identified 55 consistently downregulated genes in weedy plots. Many of the downregulated genes were heat shock genes. Fourteen genes were consistently upregulated. Several transcription factors including a PHYTOCHROME INTERACTING FACTOR 3-like gene (PIF3) were included among the upregulated genes. Gene set enrichment analysis indicated roles for increased oxidative stress and jasmonic acid signaling responses during weed stress. The relationship of this weed-induced PIF3 gene to genes involved in shade avoidance responses in Arabidopsis provide evidence that this gene may be important in the response of soybean to weeds. These results suggest that the weed-induced PIF3 gene will be a target for manipulating weed tolerance in soybean. No claim to original US government works New Phytologist © 2015 New Phytologist Trust.

  14. Effect of Non-chemical Procedures of Weed Management on Growth Characteristics and Yield of Cumin (Cuminnum cyminum L.

    Directory of Open Access Journals (Sweden)

    Surur Khorramdel

    2018-02-01

    weed infested control. Operation of tillage at night performed with moon light. Seed bed prepared, irrigated and weed removed at 28th February by using surface cultivation for false seed bed treatment. Cover crops removed and added to the soil at 5th March. After land preparation, 2.5 t.ha-1 crop residues of each species added to the soil. Cover crops planted as dense at 5th November then all plots irrigated and then seeding operation was done. Plant height, yield components, biological yield, seed yield, essential oil content and essential oil yield of cumin were measured accordingly. The treatments were run as an analysis of variance (ANOVA to determine if significant differences existed among treatments means. Multiple comparison tests were conducted for significant effects using the LSD test. Results and Discussion The results showed that the growth characteristics, yield components, biological yield, seed yield and essential oil yield of cumin were significantly affected by non-chemical management procedures (p≤0.01. The maximum biological and seed yield were observed in hairy vetch with 220.7 and 103.1 g. m-2 and these minimum were for control with 72.4 and 28.6 g. m-2, respectively. These traits enhanced more than 100% for all management treatments compared to control. The highest essential oil yield of cumin was recorded in hairy vetch (2.8 g. m-2 and the lowest was for control (0.6 g.m-2. Conclusion Non-chemical weed management strategies had significantly effect on plant height, yield components and yield of cumin. Cover crops and crop residues enhanced cumin yield due to physical and chemical soil characteristics, moisture conservation and cell swelling improvement that they increased growth and production of photosynthetic matters. Generally, cover crop is a safe and effective technique for weed control that may decrease the necessity for chemical approaches to crop and soil. Acknowledgement This research (24119.2 was funded by Vice Chancellor for

  15. Weed Identification and Control in Vegetable Crops.

    Science.gov (United States)

    Ferretti, Peter A., Comp.

    This agriculture extension service publication from Pennsylvania State University examines weed control and identification in vegetable crops. Contents include: (1) Types of weeds; (2) Reducing losses caused by weeds, general control methods and home garden weed control; (3) How herbicides are used; (4) Specific weeds in vegetable plantings; and…

  16. Combining a weed traits database with a population dynamics model predicts shifts in weed communities

    DEFF Research Database (Denmark)

    Storkey, Jonathan; Holst, Niels; Bøjer, Ole Mission

    2015-01-01

    A functional approach to predicting shifts in weed floras in response to management or environmental change requires the combination of data on weed traits with analytical frameworks that capture the filtering effect of selection pressures on traits. A weed traits database (WTDB) was designed, po...

  17. Combining a weed traits database with a population dynamics model predicts shifts in weed communities.

    Science.gov (United States)

    Storkey, J; Holst, N; Bøjer, O Q; Bigongiali, F; Bocci, G; Colbach, N; Dorner, Z; Riemens, M M; Sartorato, I; Sønderskov, M; Verschwele, A

    2015-04-01

    A functional approach to predicting shifts in weed floras in response to management or environmental change requires the combination of data on weed traits with analytical frameworks that capture the filtering effect of selection pressures on traits. A weed traits database (WTDB) was designed, populated and analysed, initially using data for 19 common European weeds, to begin to consolidate trait data in a single repository. The initial choice of traits was driven by the requirements of empirical models of weed population dynamics to identify correlations between traits and model parameters. These relationships were used to build a generic model, operating at the level of functional traits, to simulate the impact of increasing herbicide and fertiliser use on virtual weeds along gradients of seed weight and maximum height. The model generated 'fitness contours' (defined as population growth rates) within this trait space in different scenarios, onto which two sets of weed species, defined as common or declining in the UK, were mapped. The effect of increasing inputs on the weed flora was successfully simulated; 77% of common species were predicted to have stable or increasing populations under high fertiliser and herbicide use, in contrast with only 29% of the species that have declined. Future development of the WTDB will aim to increase the number of species covered, incorporate a wider range of traits and analyse intraspecific variability under contrasting management and environments.

  18. Effect of ploughing frequency and weeding methods on weeds and ...

    African Journals Online (AJOL)

    User

    Five tillage practices ... 2.5 l ha-1, Duplosan plus one hand weeding at 30 days after emergence (DAE); ... weed on time, is one of the major constraints in wheat ... management factors and soil type (Yohannes, 1982). .... The finding at ICARDA (1984) shows that ..... selling price of the crop changes, the farmer can still get a.

  19. Competitive Ability of Lentil (Lens culinaris L. Cultivars to Weed Interference under Rain-fed Conditions

    Directory of Open Access Journals (Sweden)

    Javad Hamzei

    2016-07-01

    weeding and weedy check and five lentil cultivars (Bilehsavar, Karalinta, Kimia, Seymareh and local. This experiment was studied at the Research Farm of Bu-Ali Sina University during the growing season of 2012-2013. Plots were not irrigated because lentil was grown under dry land conditions. Weeds were counted at their greatest intensity, and their identification was much easier. Three square meter samples were randomly collected from each sub-plot for evaluation the weed biomass. At harvest, two outer rows for each plot and 50 cm from each end of the plots were left as borders and the central rows were harvested. Yield and yield components of lentil were classified as biological yield, grain yield, 1000- seed weight, number of pods plant-1, number of seeds per pod and plant height. Results and discussion The results showed that the effects of weed control and cultivar was significant on all traits but plant height and chlorophyll meter reading was not affected by cultivar. Also, the effects of treatment interaction were significant on grain and biological yield. The highest grain and biological yield (110 and 338 g.m-2, respectively was observed at local cultivar on hand weeding treatment. The lowest mean for these traits with a reduction of 82 and 70%, respectively, belonged to Karalinta cultivar on weedy control treatment. Weed interference decreased yield and yield component of all lentil cultivars significantly. Maximum and minimum weed dry matter and weed density belonged to Karalinta and local cultivars, respectively. The highest values for competition and ability of tolerance indices (2.02 and 52.82, respectively belonged to Local cultivar and the lowest values of these indices (0.49 and 23.53, respectively were achieved at Karalinta cultivar. Conclusion It can be concluded that local and Karalinta cultivars were the resistant and sensitive cultivars to weed presence, respectively.

  20. Overview of glyphosate-resistant weeds worldwide.

    Science.gov (United States)

    Heap, Ian; Duke, Stephen O

    2018-05-01

    Glyphosate is the most widely used and successful herbicide discovered to date, but its utility is now threatened by the occurrence of several glyphosate-resistant weed species. Glyphosate resistance first appeared in Lolium rigidum in an apple orchard in Australia in 1996, ironically the year that the first glyphosate-resistant crop (soybean) was introduced in the USA. Thirty-eight weed species have now evolved resistance to glyphosate, distributed across 37 countries and in 34 different crops and six non-crop situations. Although glyphosate-resistant weeds have been identified in orchards, vineyards, plantations, cereals, fallow and non-crop situations, it is the glyphosate-resistant weeds in glyphosate-resistant crop systems that dominate the area infested and growing economic impact. Glyphosate-resistant weeds present the greatest threat to sustained weed control in major agronomic crops because this herbicide is used to control weeds with resistance to herbicides with other sites of action, and no new herbicide sites of action have been introduced for over 30 years. Industry has responded by developing herbicide resistance traits in major crops that allow existing herbicides to be used in a new way. However, over reliance on these traits will result in multiple-resistance in weeds. Weed control in major crops is at a precarious point, where we must maintain the utility of the herbicides we have until we can transition to new weed management technologies. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Analysis of the Heterogeneity of Weed Infestation in Cereal Stands

    Directory of Open Access Journals (Sweden)

    Jan Winkler

    2015-01-01

    Full Text Available The aim of this study was to evaluate the heterogeneity of the incidence of individual weed species on a selected experimental field. This field was situated in the cadastre of the village Žabčice (South Moravian Region, Czech Republic. To evaluate the intensity of weed infestation, a field experiment was established. In 2011, altogether 33 weed species were identified in a stand of spring barley. In the next year, the total number of weeds in a stand of winter wheat was 22. Basing on results of the evaluation of infestation heterogeneity it was possible to detect the following trends: The first one concerned the incidence of significantly dominant species Chenopodium album and Veronica hederifolia in stands of spring barley and winter wheat, respectively. The second one expressed the incidence of the so-called sub-dominant species. Regarding the character of the incidence of these weed species it would be suitable to kill them by means of a targeted application of herbicides. Finally, the third trend concerned the incidence of that group of weeds that occurred in the major part of the experimental plot but in low numbers only. The abundance of these species was minimal and the total number of weed plants did not exceed the limit of 100 specimens. This group of weeds involved also those species that were markedly more frequent on plots situated closer to the margin of the experimental field. The targeted application of herbicides can be performed on plots with a lower level of weed infestation; another possibility, however, seems to be a targeted intervention that helps to control the incidence of a certain weed species and/or that is performed along the margin of the field where the different weed species are more frequent.

  2. Effect of Nitrogen Fertilizer on Weeds Growth and Emergence and Yield and Yield Components of Corn (Zea mays L.

    Directory of Open Access Journals (Sweden)

    M. Gholamshahi

    2017-01-01

    components of corn and weeds growth and emergence, a field study was conducted in research Station of Natural Resources Research Centre, Kerman province. Materials and Methods: This experiment was conducted using a randomized complete block design with three replications. The treatments consisted of different levels of nitrogen in four levels (0, 80, 160, 240 kg ha-1 urea fertilizer (46%. In addition, for assessment the effect of experimental treatments, each plot separated into two parts (complete control and non-control of weeds. Preparing the field was done with autumn plowing and spring disc. Corn seeds (single cross 704 were planted on rows in the spring with hand and with the density of 71000 plants per hectare with row spacing of 70 cm and 20cm. Irrigation was performed on average every7 days. Weeds in the control treatment were weeding by hand twice during the growing season. Results and Discussion: The results showed that nitrogen application in combination with weeds control increased yield and yield components of corn and the other growth traits, significantly. The maximum corn yield observed 12/8 kg under high nitrogen treatment (240 kg ha-1 with 88/82% increase compare with non-fertilizer treatment. Moreover, increase in nitrogen imposed a significant positive affect on height, yield and yield components including (Length and ear diameter and ear dry matter, the number of grains in row and the number of rows in ear, hundred grain weight. Nitrogen is one of the factors affecting the development of leaf area per plant and therefore, the development of the corn canopy. It seems that the increase of nitrogen during the tassel stage and seed formation which are the most sensitive stages to nitrogen absorption and photosynthesis, increased the length of ear. In addition, results of the experiment indicated that control of weeds had significant effect on different growth factors. Furthermore, the increase nitrogen rate caused to weeds emergence rate and dry weight

  3. The effect of sowing strategy, row distance and mechanical weed control on weeds and yield in organic winter wheat

    OpenAIRE

    Rasmussen, Ilse A.

    2002-01-01

    A series of field experiments were carried out in winter wheat grown under organic conditions in Denmark on fields with different weed pressure. The treatments were sowing strategy (normal sowing time, late sowing and false seedbed), row distance (12 cm and 24 cm row distance) and weed control method (untreated, mechanical weed control (weed harrowing at 12 cm supplemented with row hoeing at 24 cm), and herbicide weed control). Weed biomass was largest at the normal sowing time and was reduce...

  4. Weed communities of rain-fed lowland rice vary with infestation by Rhamphicarpa fistulosa

    Science.gov (United States)

    Houngbédji, Tossimidé; Dessaint, Fabrice; Nicolardot, Bernard; Shykoff, Jacqui A.; Gibot-Leclerc, Stéphanie

    2016-11-01

    The facultative hemiparasitic plant Rhamphicarpa fistulosa (Orobanchaceae) thrives in seasonally wet soils in sub-Saharan Africa, mainly in marginal lowland rice growing environments where weeds are already a major constraint for rice production. Because lowland rice production is increasing in tropical Africa, it is important to ascertain the influence of R. fistulosa on weed plant communities in these rice-growing habitats. We investigated weed plant community richness and composition at four different levels of R. fistulosa infestation across two years of surveys from lowland rice fields in northern Togo (West Africa). Despite a lack of significant differences in community richness among sites with different R. fistulosa infestation levels, there were significant differences in community composition, both when estimated from presence-absence data and from relative abundance data, after controlling statistically for geographic proximity among sites. Rhamphicarpa fistulosa infestation, therefore, may influence the competitive balance between rice and its weeds and shape weed community structure. However, experimental studies are required to elucidate the weed host range of R. fistulosa and the direct and indirect effects of this hemiparasite in rice fields in order to predict its net impact on rice and its weed species.

  5. Biology, ecology and management of the invasive parthenium weed (Parthenium hysterophorus L.).

    Science.gov (United States)

    Adkins, Steve; Shabbir, Asad

    2014-07-01

    Parthenium weed (Parthenium hysterophorus L.) is one of the most aggressive invasive weeds, threatening natural ecosystems and agroecosystems in over 30 countries worldwide. Parthenium weed causes losses of crops and pastures, degrading the biodiversity of natural plant communities, causing human and animal health hazards and resulting in serious economic losses to people and their interests in many countries around the globe. Several of its biological and ecological attributes contribute towards its invasiveness. Various management approaches (namely cultural, mechanical, chemical and biological control) have been used to minimise losses caused by this weed, but most of these approaches are ineffective and uneconomical and/or have limitations. Although chemical control using herbicides and biological control utilising exotic insects and pathogens have been found to contribute to the management of the weed, the weed nevertheless remains a significant problem. An integrated management approach is proposed here for the effective management of parthenium weed on a sustainable basis. © 2014 Society of Chemical Industry.

  6. Determining treatment frequency for controlling weeds on traffic islands using chemical and non-chemical weed control

    DEFF Research Database (Denmark)

    Rask, Anne Merete; Larsen, S.U.; Andreasen, Christian

    2013-01-01

    Many public authorities rely on the use of non-chemical weed control methods, due to stringent restrictions on herbicide use in urban areas. However, these methods usually require more repeated treatments than chemical weed management, resulting in increased costs of weed management. In order...... of treatments per year were required: glyphosate 2.5, hot water 3, flames 5, hot air/flames 5.5 and steam 5.5 treatments. The results demonstrate that the weed control should be adjusted to the prescribed quality for the traffic islands by regularly assessing the need for weed control. They also show...... to investigate the efficacy of four non-chemical weed control methods and glyphosate treatment, experiments were carried out on traffic islands in the growing seasons 2005 and 2006. Three trial sites were each divided into six treatment areas, which were either treated with glyphosate, flame, steam, hot air...

  7. Weed Competition and its Effects on Pwani Hybrid 1 Maize Grain Yields in Coastal Kenya

    International Nuclear Information System (INIS)

    Kamau, G.M.; Saha, H.M.

    1999-01-01

    Weed competition is a serious constraint to maize production in coastal Kenya. A trial to asses the effects of weed competition on performance of maize was planted at Regional Research Centre-Mtwapa and Msabaha Research Sub-centre-Malindi in 1992. Pwani hybrid 1 maize was used in the trials. Weeding was done at weekly intervals from germination up to the sixth week in an additive weed removal system and plots maintained weed free afterwards. A weedy and a weed free plot were used as checks. Data on plant counts plant heights, weed biomass, weed identification and maize grain yield at 15 % MC were all recorded. There was a significant difference between weed and weedy free plots for grain yield, plant height and weed biomass for both sites. A 53% maize grain yield reduction due to weed competition was recorded. A 3% grain yield reduction equivalent to 1.03 bags for every week's delay in weeding after the first to weeks was realised for both sites. There was a corresponding grain yield loss as delay in weeding increased

  8. The synergistic effects of 2,4-D dimethyl amine and propanil herbicides on weed population in rice agroecosystem

    International Nuclear Information System (INIS)

    Nashriyah Mat; Ramli Ishak; Sabri Junoh; Ismail Sahid

    2002-01-01

    Four treatments with the herbicides 2,4-D dimethyl amine and propanil were carried out in two consecutive rice planting seasons, to study the synergistic effect of 2,4-D dimethyl amine and propanil on rice weed populations at Pasir Panjang, the Northwest Selangor Project (PBLS), Projek Barat Laut Selangor) rice granary area. The treatments were control, 1x recommended rate (single dose), 2x recommended rate (double dose) of 2,4-D dimethyl amine and farmer practice. In all plots, propanil herbicide was applied at similar rate. Among the ecological indices measured were Simpson Index of diversity and importance (I.V.). A total number of 19 weed species was identified and the most common important weed was Najas graminae Del. The second most commonly found important weed was Scirpus lateriflorus Gmel. Other important weeds frequently found were Echinochloa crus-galli (L.) Beauv. and Fimbristylis miliacea (L.) Vahl. In the rice agroecosystem, species diversity of weeds was affected but total weed biomass was not affected synergistically by the mixture of 2,4-D dimethyl amine and propanil. The negative synergistic effect of 2,4-D dimethyl amine and propanil was to increase the total biomass of Scirpus lateriflorus, at 2x recommended dose rate of 2,4-D dimethyl amine. (Author)

  9. Annual losses of weed seeds due to predation in organic cereal fields

    NARCIS (Netherlands)

    Westerman, P.R.; Wes, J.S.; Kropff, M.J.; Werf, van der W.

    2003-01-01

    1. Post-dispersal seed losses in annual arable weed species are poorly quantified, but may be of significance for natural population control, especially if they can be manipulated. We hypothesized that weed seed predation on the soil surface was significant, so we measured rates in the field to

  10. Applicator Training Manual for: Aquatic Weed Control.

    Science.gov (United States)

    Herron, James W.

    The aquatic weeds discussed in this manual include algae, floating weeds, emersed weeds, and submerged weeds. Specific requirements for pesticide application are given for static water, limited flow, and moving water situations. Secondary effects of improper application rates and faulty application are described. Finally, techniques of limited…

  11. The diversity of weed species occurring in living mulch in an apple orchard

    Directory of Open Access Journals (Sweden)

    Maria Licznar-Małańczuk

    2014-04-01

    Full Text Available In a study conducted at the Research Station of the Wrocław University of Environmental and Life Sciences, weed occurrence in living mulches maintained in apple tree rows of ‘Pinova’ cv. was assessed during the first seven years after sowing. The trees were planted in spring 2004 (3.5 × 1.2 m. In the same year, living mulches: colonial bent grass, white clover and French marigold, were sown into 1 m wide tree rows. Blue fescue, the only perennial cover crop with herbicide application against dicot weeds once in the second year after sowing, was introduced in the second year after planting the trees to replace dwarf nasturtium which was sown in the year of orchard establishment. In the inter-row spaces, perennial grass was maintained. During the first seven years, variation in weeds was observed depending on living mulch. Multi-species weed infestation persisted throughout the study period only in the case of annually resown French marigold. Perennial living mulches were significantly suppressed the annual weeds. Significant suppression of Taraxacum officinale Web. was found where the soil surface was covered by perennial grass sod in more than ¾. The maintenance of blue fescue resulted in significantly lower average soil coverage by Elymus repens (L. Gould; the growth of this weed significantly contributed to the reduction of white clover sod and French marigold plants.

  12. Effect of stale seedbed preparations and subsequent weed control in lettuce (cv. Iceboll) on weed densities

    NARCIS (Netherlands)

    Riemens, M.M.; Weide, van der R.Y.; Bleeker, P.O.; Lotz, L.A.P.

    2007-01-01

    The effects of stale seedbed preparations and several weed control methods on the emergence of weeds in lettuce were studied. The specific goal was to evaluate the use of a stale seedbed in combination with chemical or mechanical weed control methods in the field. Depending on location and year,

  13. The future for weed control and technology.

    Science.gov (United States)

    Shaner, Dale L; Beckie, Hugh J

    2014-09-01

    This review is both a retrospective (what have we missed?) and prospective (where are we going?) examination of weed control and technology, particularly as it applies to herbicide-resistant weed management (RWM). Major obstacles to RWM are discussed, including lack of diversity in weed management, unwillingness of many weed researchers to conduct real integrated weed management research or growers to accept recommendations, influence or role of agrichemical marketing and governmental policy and lack of multidisciplinary research. We then look ahead to new technologies that are needed for future weed control in general and RWM in particular, in areas such as non-chemical and chemical weed management, novel herbicides, site-specific weed management, drones for monitoring large areas, wider application of 'omics' and simulation model development. Finally, we discuss implementation strategies for integrated weed management to achieve RWM, development of RWM for developing countries, a new classification of herbicides based on mode of metabolism to facilitate greater stewardship and greater global exchange of information to focus efforts on areas that maximize progress in weed control and RWM. There is little doubt that new or emerging technologies will provide novel tools for RMW in the future, but will they arrive in time? © 2013 Her Majesty the Queen in Right of Canada Pest Management Science © 2013 Society of Chemical Industry.

  14. Variation in Weed Seed Fate Fed to Different Holstein Cattle Groups.

    Directory of Open Access Journals (Sweden)

    Salman Rahimi

    Full Text Available Weed seeds may maintain their viability when passing through the digestive tract of cattle and can be therefore dispersed by animal movement or the application of manure. Whether different cattle types of the same species can cause differential weed seed fate is largely unknown to us particularly under non-grazed systems similar to Holstein-Friesian dairy farming. We investigated the effect on the seed survival of four weed species in the digestive tracts of four groups of Holstein cattle: lactating cows, feedlot male calves, dry cows and growing heifers. The weed species used were Cuscuta campestris, Polygonum aviculare, Rumex crispus and Sorghum halepense. Cattle excretion was sampled for recovery and viability of seeds at four 24 hourly intervals after seed intake. The highest seed recovery occurred two days after seed intake in all cattle groups. Averaged over weed species, dry and lactating cows had the lowest and highest seed recovery of 36.4% and 74.4% respectively. No significant differences were observed in seed recovery of the four weed species when their seeds were fed to dry cows. Based on a power model fitted to seed viability data, the estimated time to 50% viability loss after seed intake, over all cattle groups ranged from 65 h (R. crispus to 76 h (P. aviculare. Recovered seeds from the dung of feedlot male calves showed the highest mortality among cattle groups. Significant correlation was found between seed viability and ruminal pH (r = 0.86; P<0.05. This study shows that management programs aiming to minimize weed infestation caused by livestock should account for the variation amongst cattle groups in seed persistence. Our findings can be used as a guideline for evaluating the potential risk of the spread of weeds via the application of cattle manure.

  15. Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production.

    Directory of Open Access Journals (Sweden)

    Judith A Odhiambo

    Full Text Available Weed competition is a significant problem in maize (Zea mays, L. production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L. during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT, no-till (NT and conventional (CT applied to three cropping systems: continuous maize/bean intercropping (TYPICAL, maize/bean intercropping with relayed mucuna after bean harvest (RELAY and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP. Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha(-1 in MT and $149.60 ha(-1 in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations.

  16. Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production.

    Science.gov (United States)

    Odhiambo, Judith A; Norton, Urszula; Ashilenje, Dennis; Omondi, Emmanuel C; Norton, Jay B

    2015-01-01

    Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha(-1) in MT and $149.60 ha(-1) in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations.

  17. Prospects for site specific weed management

    DEFF Research Database (Denmark)

    Christensen, Svend; Rasmussen, Jesper; Pedersen, Søren Marcus

    2014-01-01

    Research on Site Specific Weed Management (SSWM) started in the late 80's. Since that moment, considerable research has been conducted on different aspects of SSWM, from fundamental studies on the spatial ecology of weeds to the applied development and testing of new technologies for weed detection...

  18. Herbicide-resistant weed management: focus on glyphosate.

    Science.gov (United States)

    Beckie, Hugh J

    2011-09-01

    This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds. Copyright © 2011 Society of Chemical Industry.

  19. Competition between crops and weeds in the Zanderij area of Suriname

    NARCIS (Netherlands)

    Everaarts, A.P.

    1991-01-01

    A weed flora rapidly built up with the cultivation of annual crops on two experimental farms in the Zanderij area of Suriname, despite the fact that the farms were newly established in forested areas. Studies indicated that without adequate weed control, significant yield losses occurred in

  20. The effect of intercropping on weed infestation of a spring barley crop cultivated in monoculture

    Directory of Open Access Journals (Sweden)

    Ewa Kwiecińska-Poppe

    2012-12-01

    Full Text Available This paper presents the results of a study carried out in the years 2005-2007 in the Bezek Experimental Farm near the city of Chełm, Poland, on heavy mixed rendzina soil. The effect of intercropping, using red clover (cv. Dajana and white clover (cv. Astra, on weed infestation of a spring barley crop was studied. The species composition of weeds in the spring barley crop changed to a small extent under the influence of the application of clover intercropping, whereas the population size of particular species showed large fluctuations. In the spring barley crop with the red clover intercrop, Sonchus arvensis occurred in greatest numbers among dicotyledonous weed species. In the barley crop with white clover and without intercrop, Viola arvensis and Sonchus arvensis were the dominant dicotyledonous species. Setaria pumila was the dominant monocotyledonous species in all the treatments. Intercropping using red and white clover clearly limited the growth and development of weeds. The red clover intercrop in the spring barley crop better reduced the infestation with dicotyledonous weeds and also significantly reduced the number of monocotyledonous weeds and the total number of weeds, whereas the white clover intercrop limited only the number of monocotyledonous weeds. The application of the herbicide Chwastox Extra 300 SL significantly reduced the fresh weight of weeds found in the spring barley crop. The presence of the intercrop resulted in different total numbers of weeds in particular treatments. Intercropping distinctly limited the occurrence of the following weed species: Sonchus arvensis, Fallopia convolvulus, Melandrium album, Amaranthus retroflexus, Veronica arvensis and Medicago lupulina. The investigated intercrop species also reduced the biomass of weeds. The application of the herbicide did not differentiate the number of monocotyledonous weeds, which resulted from the application of Chwastox Extra 300 SL that controls only

  1. Chemical Weed Control in a Two-Year-Old Walnut Planting

    Science.gov (United States)

    Gayne G. Erdmann; Leeroy Green

    1967-01-01

    Six herbicide mixtures were sprayed directly on broadleaf weeds and grasses competing with black walnut trees. Mixtures of papquat (1/2 lb/acre) with simazine (4 lb/acre) or atrazine (4 lb/acre), and amitrole (2 lb/acre) plus simazine (4 lb/acre) gave satisfactory weed control which resulted in significantly better tree height and diameter growth.

  2. An ultrasonic system for weed detection in cereal crops.

    Science.gov (United States)

    Andújar, Dionisio; Weis, Martin; Gerhards, Roland

    2012-12-13

    Site-specific weed management requires sensing of the actual weed infestation levels in agricultural fields to adapt the management accordingly. However, sophisticated sensor systems are not yet in wider practical use, since they are not easily available for the farmers and their handling as well as the management practice requires additional efforts. A new sensor-based weed detection method is presented in this paper and its applicability to cereal crops is evaluated. An ultrasonic distance sensor for the determination of plant heights was used for weed detection. It was hypothesised that the weed infested zones have a higher amount of biomass than non-infested areas and that this can be determined by plant height measurements. Ultrasonic distance measurements were taken in a winter wheat field infested by grass weeds and broad-leaved weeds. A total of 80 and 40 circular-shaped samples of different weed densities and compositions were assessed at two different dates. The sensor was pointed directly to the ground for height determination. In the following, weeds were counted and then removed from the sample locations. Grass weeds and broad-leaved weeds were separately removed. Differences between weed infested and weed-free measurements were determined. Dry-matter of weeds and crop was assessed and evaluated together with the sensor measurements. RGB images were taken prior and after weed removal to determine the coverage percentages of weeds and crop per sampling point. Image processing steps included EGI (excess green index) computation and thresholding to separate plants and background. The relationship between ultrasonic readings and the corresponding coverage of the crop and weeds were assessed using multiple regression analysis. Results revealed a height difference between infested and non-infested sample locations. Density and biomass of weeds present in the sample influenced the ultrasonic readings. The possibilities of weed group discrimination were

  3. Developments in physical weed control in Northwest Europe

    Directory of Open Access Journals (Sweden)

    Riemens, Marieen

    2016-02-01

    Full Text Available In North West Europe there is an increasing need for advanced weed control methods. This paper gives an overview of the developments in physical weed control methods. Current innovations in interrow weeding focus on systems that take over the steering function of the driver in order to make them more precise and reduce crop losses. The latest developments in intrarow weeding techniques involve technologies that automatically detect and classify crop and weed plants and use this information to guide a weeding device. Several commercially available examples are presented.

  4. Weed-Species Abundance and Diversity Indices in Relation to Tillage Systems and Fertilization

    Directory of Open Access Journals (Sweden)

    Ilias S. Travlos

    2018-04-01

    Full Text Available Weeds pose a major threat to world agriculture by reducing detrimentally crop yield and quality. However, at the same time, weeds are major interacting components of the agroecosystems. Abundance and diversity of weeds vary significantly among the several communities. In order to evaluate each community's structure and the interactions among them, several population indices are used as key tools. In parallel, various cultivation and land management strategies, such as tillage and fertilization, are commonly used in terms of integrated weed management. Estimating the response of weed species on those practices is crucial for both biodiversity maintenance and alternative weed control methods. Many experiments have confirmed the fundamental role of tillage intensity and nutrition supply in weed species' abundance and diversity. For instance, in some studies, the abundance of perennial weeds was doubled under reduced tillage intensity. In addition, higher values of Shannon-Weiner and Pielou indices were reported in the PK fertilization treatment compared to the control and NK fertilization treatments. The objective of this paper is to provide a brief overview of the key results of these experiments and summarize the part of the literature related to the effect of tillage systems and fertilization on weed species abundance and diversity. Such knowledge could contribute to the sound design and implementation of integrated weed management programs which in turn may lead to a decrease in the density of serious and noxious weeds and an increase in the overall balance of agroecosystems.

  5. Economical Evaluation of Faba bean (Vicia faba and Maize (Zea mays L. Intercropping Based on Total Relative Value Index and Weeds Growth Reduction

    Directory of Open Access Journals (Sweden)

    J. Hamzei

    2016-05-01

    Full Text Available The chemical control of weeds raises serious concerns about food safety and environmental quality, which have necessitated the need for non chemical weed management techniques such as intercropping. Intercropping can suppress weeds and reduce the use of herbicides in production systems. Therefore, the objective of this work was to evaluate the effects of intercropping of faba bean and maize, as well as hand-weeding on maize grain yield and total grain yield. The experiment was carried out during growing season of 2010 as a randomized complete block design with three replications at the Agricultural Research Station, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran. Sole cropping of maize with weed control (MWF, sole cropping of maize without weed control (MWI, intercropping of 15% faba bean+maize (M+15%F, 30% faba bean+maize (M+30%F, 45% faba bean+maize (M+45%F  and sole cropping of faba bean were the experimental treatments. Weed biomass and density were affected by treatments. With increasing faba bean density in the intercropping treatments, weed biomass and density decreased significantly from 85 plants and 310 g m-2 for MWI treatment to 22 plants and 63 g m-2 for M+45%F treatment, respectively. The greatest number of seed row per ear, seed number per ear and grain and biological yields (8033 and 17933 kg ha-1, respectively were achieved at MWF treatment and the smallest values for these attributes were revealed at MWI treatment. There was no significant difference between MWF and M+45%F treatments for total grain yield (i.e. grain yield of maize + faba bean. Sole cropping of faba bean led to the greatest yield components and grain and biological yields. With increasing faba bean density in intercropping treatments, above mentioned traits (except number of pods per plant were increased significantly. The great values for weed control efficiency (73% and total relative value (1.14 were achieved at M+45%F treatment. Results of

  6. The Effect of Laser Treatment as a Weed Control Method

    DEFF Research Database (Denmark)

    Mathiassen, Solvejg K; Bak, Thomas; Christensen, Svend

    2006-01-01

    at the cotyledon stage. Experiments were carried out under controlled conditions, using pot-grown weeds. Two lasers and two spot sizes were tested and different energy doses were applied by varying the exposure time. The biological efficacy was examined on three different weed species: Stellaria media (common...... was related to wavelength, exposure time, spot size and laser power. The efficacy also varied between the weed species. The results indicate that the efficacy of laser treatments can be improved by a more precise pointing of the laser beam towards the apical meristems and optimisation of the energy density...... (exposure time and spot size of the laser beam). The experiment also showed a significant difference between two wavelengths. In order to improve the performance and to validate the efficacy on a broader spectrum of weed species, further research and development is needed....

  7. Grass and weed killer poisoning

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002838.htm Grass and weed killer poisoning To use the sharing features on this page, please enable JavaScript. Many weed killers contain dangerous chemicals that are harmful if ...

  8. Circadian response of annual weeds to glyphosate and glufosinate.

    Science.gov (United States)

    Martinson, Krishona B; Sothern, Robert B; Koukkari, Willard L; Durgan, Beverly R; Gunsolus, Jeffrey L

    2002-03-01

    Five field experiments were conducted in 1998 and 1999 in Minnesota to examine the influence of time of day efficacy of glyphosate [N-(phosphonomethyl)glycine] and glufosinate [2-amino-4-(hydroxymethyl-phosphinyl)butanoic acid] applications on the control of annual weeds. Each experiment was designed to be a randomized complete block with four replications using plot sizes of 3 x 9 m. Glyphosate and glufosinate were applied at rates of 0.421 kg ae/ha and 0.292 kg ai/ha, respectively, with and without an additional adjuvant that consisted of 20% nonionic surfactant and 80% ammonium sulfate. All treatments were applied with water at 94 L/ha. Times of day for the application of herbicide were 06:00h, 09:00h, 12:00h, 15:00h, 18:00h, 21:00h, and 24:00h. Efficacy was evaluated 14 d after application by visual ratings. At 14 d, a circadian response to each herbicide was found, with greatest annual weed control observed with an application occurring between 09:00h and 18:00h and significantly less weed control observed with an application at 06:00h, 21:00h, or 24:00h. The addition of an adjuvant to both herbicides increased overall efficacy, but did not overcome the rhythmic time of day effect. Results of the multiple regression analysis showed that after environmental temperature, time of day was the second most important predictor of percent weed kill. Thus, circadian timing of herbicide application significantly influenced weed control with both glyphosate and glufosinate.

  9. Evaluation of weeds as possible hosts of the potyviruses associated with tree tomato (Solanum betaceum Cav. viroses

    Directory of Open Access Journals (Sweden)

    Sierra S. Adela

    2012-04-01

    Full Text Available

    To determine possible weed hosts of potyviruses associated with the disease known as “tree tomato virus disease” in Antioquia department (Colombia, a sampling was conducted to identify weed species commonly found in commercial crops of S. betaceum affected by the virus and the possible presence of the virus in these plants. The encountered weed species were grouped into seven different taxonomic families, within which we evaluated the ten most common species. The selected weeds, three indicator species of the virus and tree tomato plants were grown in a greenhouse and mechanically inoculated with an extract of infected tree tomato tissue. One month after inoculation, the tree tomato plants and Nicotiana tabacum showed symptoms of the disease and were serologically positive, whereas none of the weeds showed symptoms or were positive for potyviruses serology. In order to confirm that the detection of the virus was not caused by low viral titers that did not reach the minimum detection level of the test used, the tomato tree plants were reinoculated with an extract of sap from the studied weeds and potyviruses was not detected in any of the tested weeds and therefore cannot be considered, with the utilized methodology, as hosts for the potyviruses affecting tree tomato plants.

  10. The Weeds Response to the Winter Vetch (Vicia villosa and Chicklingpea (Lathyrus sativus Cover Crops under Different Tillage Methods in Corn Fields

    Directory of Open Access Journals (Sweden)

    Javad Hamzei

    2017-01-01

    samples were dried at 72 ° C for 48 hours and then were weighed. Data were analyzed using SAS software. Wherever the F test showed significant effect for a source of variance, the differences among treatments were compared by LSD test at the 0.05 level of significance. Results and Discussion: Analysis of variance showed that the effects of tillage systems and weed control methods were significant on all traits, except number of seed per ear. Also, the interaction effect of them had significant effect on number of grain row/ear and grain yield. The highest grain yield (1271 g m-2 was observed at combined treatment of winter vetch cover crop and moldboard tillage. This treatment had no significant difference with combined treatments of cover crops and tillage with chisel. In comparison with winter vetch cover crop and conventional tillage treatment, the lowest grain yield by 45% reduction was recorded at weed infested and no tillage treatment. Also, the effects of tillage systems and weed control methods and their interaction were significant on weed density and biomass. Maximum weed density and biomass (60 plant m-2 and 335 g m-2 were belonged to weed-infested treatment under no tillage system. The lowest values for weed density and biomass with reduction of 62 and 53%, respectively, were observed at combined treatment of chicklingpea cover crop and minimum tillage. Chicklingpea and winter vetch cover crops due to rapid establishment and growth capacity are more suitable for weed control. Cover crops can affect weed establishment through effects on the radiation and chemical environment of weed and inhibit weed emergence by physically impeding the progress of seedlings from accessing light as well as by releasing phytotoxins that inhibit seedling growth. Minimum tillage is often cause changes in of weed flora and their population, and this is one of the methods for integrated weed management. In general, using winter vetch and chicklingpea as a cover crop and tillage with

  11. Nature Conservation Against All? Aquatic Macrophyte De-Weeding – Cut or Conserve? A Stakeholder Analysis

    Directory of Open Access Journals (Sweden)

    Vasco Brummer

    2017-12-01

    Full Text Available De-weeding of streams and lakes occurs in Germany on a widespread level, mostly to ensure water runoff and to provide flood protection. But de-weeding also affects a range of stakeholders, who have their own reasons to support or oppose it. For the list of stakeholders identified, see chapter 4. As part of a project analysing the feasibility of using water plant biomass as a substrate for biogas production, we conducted a multi-method stakeholder analysis to evaluate stakeholders’ opinions about de-weeding. The results show a preference of all stakeholders, except those identifying with nature conservation, for aquatic de-weeding. Our findings also point to a lack of communication between stakeholders, resulting in biased opinions of the stakeholders against other stakeholders and starting points for conflict.

  12. Prediction of the competitive effects of weeds on crop yields based on the relative leaf area of weeds

    DEFF Research Database (Denmark)

    Lotz, L. A. P.; Christensen, Svend; Cloutier, D.

    1996-01-01

    . alba whereas the density model did not. A parameter that allows the maximum yield loss to be smaller than 100% was mostly not needed to describe the effects of weed competition. The parameter that denotes the competitiveness of the weed species with respect to the crop decreased the later the relative......For implementation of simple yield loss models into threshold-based weed management systems, a thorough validation is needed over a great diversity of sites. Yield losses by competition wsth Sinapis alba L. (white mustard) as a model weed, were studied in 12 experiments in sugar beet (Beta vulgaris...... L.) and in 11 experiments in spring wheat (Triticum aestivum L.). Most data sets were heller described by a model based on the relative leaf area of the weed than by a hyperbolic model based on weed density. This leaf area model accounted for (part of) the effect of different emerging times of the S...

  13. Weed seed predation in organic and conventional fields

    DEFF Research Database (Denmark)

    Navntoft, Søren; Wratten, S.D.; Kristensen, Kristian

    2009-01-01

    Enhanced biological control of weed seeds may improve sustainability of agricultural production. Biological control due to seed predation may be higher in organic fields because organic production generally supports more seed predators. To investigate such a difference, weed seed predation...... University and in two of the fields used for estimating seed predation. Recording of predators had therefore limited overlap with seed predation assays but was expected to give important information on key seed predators in the region. The mean seed removal rate was 17% in organic fields compared with 10...... edges. Overall, there was no consistent effect of distance from the field edge. Vegetation had a significant influence on the predation rates, with maximum rates at a medium-dense plant cover. Based on the video images, birds were the most important seed predators. The higher weed seed predation rate...

  14. Variation in Weed Seed Fate Fed to Different Holstein Cattle Groups.

    Science.gov (United States)

    Rahimi, Salman; Mashhadi, Hamid Rahimian; Banadaky, Mehdi Dehghan; Mesgaran, Mohsen Beheshtian

    2016-01-01

    Weed seeds may maintain their viability when passing through the digestive tract of cattle and can be therefore dispersed by animal movement or the application of manure. Whether different cattle types of the same species can cause differential weed seed fate is largely unknown to us particularly under non-grazed systems similar to Holstein-Friesian dairy farming. We investigated the effect on the seed survival of four weed species in the digestive tracts of four groups of Holstein cattle: lactating cows, feedlot male calves, dry cows and growing heifers. The weed species used were Cuscuta campestris, Polygonum aviculare, Rumex crispus and Sorghum halepense. Cattle excretion was sampled for recovery and viability of seeds at four 24 hourly intervals after seed intake. The highest seed recovery occurred two days after seed intake in all cattle groups. Averaged over weed species, dry and lactating cows had the lowest and highest seed recovery of 36.4% and 74.4% respectively. No significant differences were observed in seed recovery of the four weed species when their seeds were fed to dry cows. Based on a power model fitted to seed viability data, the estimated time to 50% viability loss after seed intake, over all cattle groups ranged from 65 h (R. crispus) to 76 h (P. aviculare). Recovered seeds from the dung of feedlot male calves showed the highest mortality among cattle groups. Significant correlation was found between seed viability and ruminal pH (r = 0.86; Pweed infestation caused by livestock should account for the variation amongst cattle groups in seed persistence. Our findings can be used as a guideline for evaluating the potential risk of the spread of weeds via the application of cattle manure.

  15. Weed Garden: An Effective Tool for Extension Education

    Science.gov (United States)

    Beck, Leslie; Patton, Aaron J.

    2015-01-01

    A weed garden was constructed to quantify and improve identification skills among clientele. The garden was planted with over 100 weed species based on surveys on problematic weeds. The weed garden proved useful for introducing additional hands-on learning activities into traditional lecture-based seminars. Through seminar and field day attendee…

  16. WEED MANAGEMENT AND CONTROL IN POTATOES

    Directory of Open Access Journals (Sweden)

    Marcelo Cleón de Castro Silva

    2011-07-01

    Full Text Available This review shows instructions to potatoes' farmer about behavior of the weeds and how to manage them so as to minimize loss of productivity through the use of control strategies for potato crop. The prevention consists in adoption of practices that prevents entry of unwanted species of weeds in the planting site. The control reduces the infestation of these species, but this practice does not eradicate them completely. However, it needs to control the weeds before the area preparation for planting the tubers until complete closure of the soil by shoots of potatoes during the critical period. After covering the soil, the potato crop does not suffer negative interference caused by weeds. The cultural practices include a good plane for harvest, plant crop rotation, the planting of appropriate plants for covering the soil, the ideal space to the planting and the correct time to potato planting. The control must be efficient to reduce the number of weeds in the area to avoid economic losses to farmers. It is necessary to establish weed management strategies in order to maintain sustainable farming systems, preserving the environment and quality of life of the farmer.

  17. Evaluation of Weed Biodiversity on Rice (Oryza sativa L Agro-ecosystems (Organic and High-input

    Directory of Open Access Journals (Sweden)

    Seyed Yusef Musavi Toghyani

    2017-12-01

    system, there was no significant difference between the two systems. Confirmations suggest that the combination of plant and animal communities and the structure of food webs in rice agro-ecosystems are very similar in different parts of the world. Comparison of different stages of sampling based on the average of the two systems revealed a decline in diversity and evenness of weeds in the fourth stage (after harvest. The evaluation of biodiversity indicators of both organic and high input systems also showed a significant reduction in weed biodiversity indices in the fourth stage compared to the previous stages. This result could be due to the disturbance of rice agro-ecosystems affected by harvesting and soil preparation for the emergence of various weed species. As regards that evidences suggest that in these conditions (disturbance and stress only certain species (especially resistant species are dominant. Despite the anticipation of increasing diversity in these conditions, because of drought stress at the harvesting stage, resistant species to stress emerged and established. In the tolerance model, despite the existence of opportunistic species, low-expected species (low R star are grown and mature at lower resource levels. The superiority of diversity in the organic system, especially in the fourth stage, can be related to the emergence and establishment of resistant weeds to disturbance and stress conditions such as Digitaria spp. X. strumarium, and E. prostrata (species of non-flooding conditions in addition to common weeds of the rice agro-ecosystems, such as Echinochloacrussgulli and Cyperus spp. (species of flooding conditions. Conclusion The results showed that in general, biodiversity (diversity and evenness indices of weeds were higher in the organic system compared to the conventional one. From this viewpoint, it can be said that the sustainability of organic systems rather than the conventional ones is mainly due to their greater diversity. Because of

  18. The Effect of Crop Seed Rate and Post Emergence Herbicide Application on Weed control and grain yield of Wheat

    Directory of Open Access Journals (Sweden)

    M. Babaei

    2017-08-01

    Full Text Available Introduction Interference weed with crop is a major concern for production in croplands particularly where modern agricultural practices such as mechanical weeding and the application of herbicides are limited. At present, the aim of weed management is to keep weed population at an acceptable level rather than to keep crop totally free of weeds. Among the weed control methods, the chemical control is the easiest one of the recent origins, as well the most successful alternative method. Materials and methods Field experiments were conducted at Shoushtar Branch, Islamic Azad University, Iran (32 0 3´ N, 480 50´ E during winters of 2012-2013 in order to evaluate the effect of sulfosulfuron and sulfosulfuron plus metsulfuron-methyl at 30 and 45 g a.i. ha-1, respectively, and wheat seed rate at 180, 200 and 220 kg ha-1 on weed control. Experiments were carry out in a randomized complete block design with a factorial arrangement and four replicates. The plot size was 6 m × 2 m. The soil was a clay loam texture, pH 7.4 and 0.6 % organic matter content. In the experimental site, the 30-year average annual rainfall is 321.4 mm, daily average annual air temperature is minimum and maximum 9.5 °C and 46.3 °C, respectively. Wheat cv. Chamran was planted in the first fortnight of November. Seedbed preparation consisted of moldboard plowing, disking and leveling. A basal fertilizer rate of 125 kg ha-1 N (form of urea (46% N, 75 kg ha-1 P2O5 (diammonium phosphate (18% N; 46% P2O5, and 60 kg K2O ha-1 (sulfate of potash (50% K2O was applied. The whole P and K and half of N were applied at sowing. The remaining half of N was top dressed with the irrigation at the booting stage. Results and Discussion As the crop population brings competition for limited resources with the weeds, we tested different seeding rates to increase crop plant density as a measure to control weeds. The weed population was significantly affected by seed rate. In general, there was an

  19. Assessment of Caesium -137 accumulation from soil to autochthonous weeds

    International Nuclear Information System (INIS)

    Sreenivasa Chari, M.; Karuna Sagar, G.; Manjaiah, K.M.

    2017-01-01

    A study was conducted at Nuclear Research Laboratory (NRL), IARI, New Delhi to obtain radio cesium ( 137 Cs) Soil-to-plant transfer factors of autochthonous weeds at low level of contamination, where contamination is a legacy of experimental activities. Studied area is sporadically covered with autochthonous weeds mainly with Amaranthus viridis, Cynodon dactylon, Cassia auriculata, Brachiaria mutica, Parthenium hysterophorus, Bohervia diffusa and some taxonomically unidentified weeds. Extractability as well as bioavailability of 137 Cs was quantified by sequential extraction. In the representative plant and soil samples, 137 Cs activity was measured directly with the 2.5” × 2.5” NaI (TI) well type detector installed in 15 cm thick lead shield and single channel gamma analyzer. Transfer factors of grassy weeds were 0.143 to 0.310 (1.43 × 10 -2 to 3.1 × 10 -2 ), for broad leaved weeds 0.103 to 0.133 (1.03 × 10 -2 to 1.33 × 10 -2 ). Increase in the activity levels increased the transfer factors of weeds. Irrespective of activity levels higher transfer factors were observed in roots ranging from 0.13 to 0.28 (1. 3 × 10 -1 to 2.8 × 10 -1 ). At both the levels (40 and 80 µci) Cynodon dactylon recorded higher root and shoot transfer factor of 2.99 and 0.29 respectively, when compared to other weeds. Significantly lower transfer factors were observed in Parthenium hysterophorus. Geochemical partitioning shown that the reducible phase (56%) is the largest sink for 137 Cs in the studied soils

  20. Effect of Time and Burial Depth on Breaking Seed dormancy and Germination of Weed Seeds

    Directory of Open Access Journals (Sweden)

    marzie mazhari

    2016-02-01

    Full Text Available Introduction: Weeds limit crop growth, development and yield through competing. Seed bank of weeds in field is one of the sources which can affect weed management and their control methods. Environmental conditions during seed maturation and following dispersal interact to influence the germination phenology of many species. Disturbance plays a key role in the maintenance of habitat for many plant species, particularly referrals, for example, fire ephemerals, desert annuals, and arable weeds. Seed germination and emergence depend on endogenous and exogenous factors. Viable seeds are dormant when all environmental conditions are appropriate for germination but seeds fail to germinate. Thus, dormancy plays an important ecological role in preventing seed germination, being a major contributor to seed persistence of some species in soil. Buried seeds of annual weeds are certainly subjected to different soil moisture conditions during their dormancy release season (winter according to the annual rainfall pattern and burial depth. Shallow buried seeds are exposed to soil moisture fluctuations that could affect their dormancy status. Laboratory studies showed that desiccation and subsequent re-hydration of seeds could stimulate germination and modify seed light requirements. Seeds buried in deeper layers of the soil would not be exposed to such fluctuations in soil moisture, but would be exposed to different soil moisture environments depending on weather and soil characteristics. The effects of interactions between temperature, and soil or seed moisture, on seed dormancy changes have been reported for several species. Therefore, the objectives of this study were to determine the effect of time and burial depth treatments on seed germination and seedling emergence of Aegilops cylindrica, Agropyrom repens, Avena fatua, Bromus dantoniae, Cynodon dactylon, Cyprus rotundus, Setaria viridis, Anthriscus sylvestris, Centurea cyanus. Materials and Methods: In

  1. Weed management strategies for castor bean crops

    Directory of Open Access Journals (Sweden)

    Augusto Guerreiro Fontoura Costa

    2014-04-01

    Full Text Available Castor bean crops are agriculturally relevant due to the quality and versatility of their oil, both for the chemical industry and for biodiesel production. Proper weed management is important for both the cultivation and the yield of castor bean crops; therefore, the intention of the present work is to review pertinent information regarding weed management, including the studies regarding weed interference periods, chemical controls for use in different crop production systems and herbicide selectivity, for castor bean crops. Weed science research for castor bean crops is scarce. One of the main weed management challenges for castor bean crops is the absence of herbicides registered with the Ministry of Agriculture, Livestock and Food Supply (MALFS. Research for viable herbicides for weed control in castor bean crops should be directed by research and/or rural extension institutions, associations and farmers cooperatives, as well as by manufactures, for the registration of these selective herbicides, which would be primarily used to control eudicotyledons in castor bean crops. New studies involving the integration of weed control methods in castor bean also may increase the efficiency of weed management, for both small farmers using traditional crop methods in the Brazilian Northeast region, as well as for areas with the potential for large scale production, using conservation tillage systems, such as the no-tillage crop production system.

  2. Critical Period of Weed Control in Aerobic Rice

    Science.gov (United States)

    Anwar, M. P.; Juraimi, A. S.; Samedani, B.; Puteh, A.; Man, A.

    2012-01-01

    Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7–49 days after seeding in off-season and 7–53 days in main season to achieve 95% of weed-free yield, and 23–40 days in off-season and 21–43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21–43 days for better yield and higher economic return. PMID:22778701

  3. Weed Recognition Framework for Robotic Precision Farming

    DEFF Research Database (Denmark)

    Kounalakis, Tsampikos; Triantafyllidis, Georgios; Nalpantidis, Lazaros

    2016-01-01

    using advanced encoding and machine learning algorithms. The resulting system can be applied in a variety of environments, plantation or weed types. This results in a novel and generic weed control approach, that in our knowledge is unique among weed recognition methods and systems. For the experimental...

  4. Germination traits of three weed species in Kosovo

    Directory of Open Access Journals (Sweden)

    A. Mehmeti

    2010-02-01

    Full Text Available Amaranthus retroflexus, Echinochloa crus-galli and Datura stramonium are the most important weed species in Kosovo. They cause severe yield depression, contaminate fodder and negatively affect growth and reproduction of other weed species. To counteract these problems, specific strategies need to be developed. Such strategies should consider information on species germination traits. In this context, our study provides information on temperature requirements for germination. Seeds of A. retroflexus, E. crus-galli and D. stramonium were harvested in two sub-regions of Kosovo (western and eastern parts differing in climate and land use. They were set for germination experiments in growth chambers at temperatures ranging from 3 to 35 °C and under field conditions. In both experiments, the germination rate differed between species and provenances. In the growth chamber experiment, germination of all three species was negligible below 15 °C and reached the highest rates between 24 and 30 °C. Seeds originating from the western part of Kosovo had higher germination rates and required a lower temperature for germination than seeds originating from the eastern part. In the field experiment, the time-dependent germination behaviour of D. stramonium differed between provenances. In general, germination started when soil temperature was above 18 °C and continued as long as the soil was moist. The results are discussed in the context of the need to develop weed management strategies against these weeds in Kosovo.

  5. Weeds optimally grow in peat swamp after burning

    Directory of Open Access Journals (Sweden)

    P.D. Susanti

    2014-07-01

    Full Text Available After clearing land by burning the peat, then the weeds and undergrowth will flourish. Even sometimes, the weeds are eventually burned again. Weed is known as a destroyer plant that has to be controlled. Through proper treatment, the existing weeds in peatlands can be potentiallly exploited. The purpose of this study was to determine the calorific value of briquettes as one of peatland weeds utilization. The results showed that the calorific value ranged from 2,492 cal/g to 5,230 cal/g. The lowest calorific value was on ‘teki kecil’ grass (Scirpus grossus Lf, while the highest calorific value was observed for ‘bantalaki grass’ (Hymenachne amplexicaulis Nees. The high calorific value of the peat weeds are potential for biomass briquettes raw materials. The utilization and use of peat weed briquettes as a raw materials expected can reduce land degradation due to peat swamp burning

  6. Spatial analysis of weed patterns

    NARCIS (Netherlands)

    Heijting, S.

    2007-01-01

    Keywords: Spatial analysis, weed patterns, Mead’s test, space-time correlograms, 2-D correlograms, dispersal, Generalized Linear Models, heterogeneity, soil, Taylor’s power law. Weeds in agriculture occur in patches. This thesis is a contribution to the characterization of this patchiness, to its

  7. Impact of different soil cultivation on weed species in winter rape (oilseed

    Directory of Open Access Journals (Sweden)

    Jan Winkler

    2005-01-01

    Full Text Available A community of weeds and crops is affected by a number of factors, including, among other things, also tillage. In the years 2000–2002, the composition of weed species in rape stands was evaluated on the fields with the total area of 551 hectares (1 hectar equals to some 2.47 acres. The evaluation was carried out with the application of methodology developed by Kühn (1982. On the fields located in the cadastral area of Olomouc – Holice, which had been cultivated in a traditional manner, 115 relevés were recorded. On the fields in the cadastral area of Bohuňovice, which had been cultivated with the application of reduced tillage, 97 relevés were recorded and evaluated. All of the above fields were subjected to the application of chemical agents reducing the occurrence of weeds. The data thus received were processed by means of multidimensional analysis of ecological data with the application of a RDA method (Redundancy Analysis. In the course of three years, 75 weed species were found on the fields under conventional tillage, on the average, 8.2 species per a relevé, while 66 weed species were found during the same period of time on the fields cultivated by means of reduced tillage, on the average, 8.6 species per a relevé. The application of RDA analysis enabled us to sort out the selected species of weeds (i.e. those the frequency of occurrence of which exceeded 15 % into three groups. The conditions provided by the conventional tillage appeared to be more satisfactory for the weed species included in the first group (Arctium tomentosum, Elytrigia repens, Helianthus tuberosus, Chenopodium album, Lolium perenne and Papaver rhoeas. The species included in the second group, i.e. Alsinula media, Apera spica-venti, Atriplex patula, Bromus sterilis, Capsella bursa-pastoris, Equisetum arvense, Fallopia convolvulus, Myosotis arvensis and Thlaspi arvense., responded to reduced tillage by the increase in cover or by increased frequency of

  8. Effect of ecological management of weed control on economical income, yield and yield components of cotton (Gossypium hirsutum L.

    Directory of Open Access Journals (Sweden)

    A. Zare Feizabadi

    2016-04-01

    Full Text Available In order to compare of ecological management of weed control on economical income, yield and yield components of cotton (Gossypium hirsutum L., a Randomized Complete Block design with 12 treatments and four replications was conducted in Mahvelat of Khorasan Razavi province, Iran. Treatments consisted of weeding, harrowing, burning, two times weeding, weeding + harrowing, weeding + burning, harrowing + harrowing, harrowing + weeding, harrowing + burning, weeding+ harrowing+ burning, weed free and weedy as a check treatment. Investigated traits were plant height, number of boll in plant, 20 boll weight, 20 boll cotton lint weight, cotton lint yield per plant, cotton yield, number and biomass of weeds, outcome, net and gross income. The result showed that treatments had significant effect (p

  9. Weed suppression greatly increased by plant diversity in intensively managed grasslands: A continental-scale experiment.

    Science.gov (United States)

    Connolly, John; Sebastià, Maria-Teresa; Kirwan, Laura; Finn, John Anthony; Llurba, Rosa; Suter, Matthias; Collins, Rosemary P; Porqueddu, Claudio; Helgadóttir, Áslaug; Baadshaug, Ole H; Bélanger, Gilles; Black, Alistair; Brophy, Caroline; Čop, Jure; Dalmannsdóttir, Sigridur; Delgado, Ignacio; Elgersma, Anjo; Fothergill, Michael; Frankow-Lindberg, Bodil E; Ghesquiere, An; Golinski, Piotr; Grieu, Philippe; Gustavsson, Anne-Maj; Höglind, Mats; Huguenin-Elie, Olivier; Jørgensen, Marit; Kadziuliene, Zydre; Lunnan, Tor; Nykanen-Kurki, Paivi; Ribas, Angela; Taube, Friedhelm; Thumm, Ulrich; De Vliegher, Alex; Lüscher, Andreas

    2018-03-01

    Grassland diversity can support sustainable intensification of grassland production through increased yields, reduced inputs and limited weed invasion. We report the effects of diversity on weed suppression from 3 years of a 31-site continental-scale field experiment.At each site, 15 grassland communities comprising four monocultures and 11 four-species mixtures based on a wide range of species' proportions were sown at two densities and managed by cutting. Forage species were selected according to two crossed functional traits, "method of nitrogen acquisition" and "pattern of temporal development".Across sites, years and sown densities, annual weed biomass in mixtures and monocultures was 0.5 and 2.0 t  DM ha -1 (7% and 33% of total biomass respectively). Over 95% of mixtures had weed biomass lower than the average of monocultures, and in two-thirds of cases, lower than in the most suppressive monoculture (transgressive suppression). Suppression was significantly transgressive for 58% of site-years. Transgressive suppression by mixtures was maintained across years, independent of site productivity.Based on models, average weed biomass in mixture over the whole experiment was 52% less (95% confidence interval: 30%-75%) than in the most suppressive monoculture. Transgressive suppression of weed biomass was significant at each year across all mixtures and for each mixture.Weed biomass was consistently low across all mixtures and years and was in some cases significantly but not largely different from that in the equiproportional mixture. The average variability (standard deviation) of annual weed biomass within a site was much lower for mixtures (0.42) than for monocultures (1.77). Synthesis and applications . Weed invasion can be diminished through a combination of forage species selected for complementarity and persistence traits in systems designed to reduce reliance on fertiliser nitrogen. In this study, effects of diversity on weed suppression were

  10. Weed detection using unmanned aircraft vehicles

    Directory of Open Access Journals (Sweden)

    Pflanz, Michael

    2014-03-01

    Full Text Available In contrast to agricultural remote sensing technologies, which are based on images from satellites or manned aircrafts, photogrammetry at low altitude from unmanned aircraft vehicles lead to higher spatial resolution, real-time processing and lower costs. Moreover multicopter aircrafts are suitable vehicles to perform precise path or stationary flights. In terms of vegetation photogrammetry this minimises motion blur and provide better image overlapping for stitching and mapping procedures. Through improved image analyses and through the recent increase in the availability of powerful batteries, microcontrollers and multispectral cameras, it can be expected in future that spatial mapping of weeds from low altitudes will be promoted. A small unmanned aircraft vehicle with a modified RGB camera was tested taking images from agricultural fields. A microcopter with six rotors was applied. The hexacopter in particular is GPS controlled and operates within predefined areas at given altitudes (from 5 to 10 m. Different scenarios of photogrammetrically weed detection have been carried out regarding to variable altitude, image resolution, weed and crop growth stages. First experiences with microcopter showed a high potential for site-specific weed control. Images analyses with regards to recognition of weed patches can be used to adapt herbicide applications to varying weed occurrence across a field.

  11. Effect of Different Methods of Chemical Weed Control Irrigation Regimes on Weed Biomass and Safflower Yield

    Directory of Open Access Journals (Sweden)

    M. Matinfar

    2011-06-01

    Full Text Available In order to investigate the effects of different weed control methods and moisture regimes on safflower (Carthamus tinctorius, a field split plot experiment based on randomized complete block design with 4 replications was conducted in Takestan Iran, during growing seasons of 2007-8. Three irrigations regimes (normal irrigation, restricted irrigation at stem elongation and restricted irrigation at  flowering stage were assigned to the main plots and nine chemical weed control method (complete hand weeding, treflan with 2 L/ha as pre plant herbicide, sonalan with 3 L/ha ad pre plant herbicide, estomp with 3 L/ha as pre plant herbicide, gallant super with 0/75 L/ha as post emergence herbicide, treflan with 2 L/ha as pre plant herbicide+ gallant super with 0/75 L/ha as post emergence herbicide, sonalan with 3 L/ha as pre plant herbicide + gallant super with 0/75 L/ha as post emergence herbicide estomp with 3 L/ha as pre plant herbicide + gallant super with 0/75 L/ha as post emergence herbicide and without hand weeding to sub- plots. At the end of growing period traits like number of head   per plant, number of seed per head, 1000 grain weight, percent of seed oil, yield of seed oil and grain yield were measured. Results indicated that treflan + gallant super treatment in restricted irrigation at stem elongation stage had the lowest dry weight of weeds. In this study maximum grain yield (2927 Kg/ha was achieved from hand weeding + usual irrigation treatments. In general treflan + gallant super treatment was the most effective treatment on safflower yield and weed control.

  12. Grain yield and competitive ability against weeds in modern and heritage common wheat cultivars are differently influenced by sowing density

    Directory of Open Access Journals (Sweden)

    Mariateresa Lazzaro

    2017-12-01

    Full Text Available Sowing density can have a strong impact on crop stand development during wheat growing cycle. In organic and low-input agriculture, and therefore with minimum or nil use of chemical herbicides, increased sowing density is expected to affect not only grain yield but also weed suppression. In this study we tested, under Mediterranean conditions, six common wheat cultivars (three modern and three heritage and two three-component mixtures (arranged by combining the three modern or the three heritage cultivars. The different crop stands were tested at sowing densities of 250 (low and 400 (high, similar to standard sowing density used by local farmers viable seeds m–2 for two growing seasons. We did not detect a significant effect of crop stand diversity (single cultivars vs mixtures on grain yield and weed suppression. Differences were ascribed to type of cultivars used (heritage vs modern. Compared to high sowing density, in modern cultivars grain yield did not decrease significantly with low sowing density, whereas in heritage cultivars it increased by 15.6%, possibly also because of 21.5% lower plant lodging. Weed biomass increased with low sowing density both in heritage and modern cultivar crop stand types. However, heritage crop stands had, on average, a lower weed biomass (56% than modern crop stands. Moreover, weed biomass in heritage crop stands at low density (6.82±1.50 g m–2 was lower than that of modern cultivars at the same sowing density (15.54±3.35 g m–2, confirming the higher suppressive potential of the former. We can conclude that lower sowing density can be advisable when using heritage crop stands as it keeps productivity while decreasing plant lodging and maintaining weeds under control.

  13. Influence of growing measures on weed interference and water status in maize

    Directory of Open Access Journals (Sweden)

    Simić Milena

    2017-01-01

    Full Text Available Growing modern hybrids in narrow plant spacing together with nitrogen and herbicide application gives an advantage to maize crops over weeds. The aim of the present investigation was to evaluate the effect of nitrogen form, maize row spacing and herbicide treatment on weed and maize biomass and water usage, as well as maize yield. The investigation was conducted at the Maize Research Institute Zemun Polje, Belgrade during 2014-2016. A field experiment was set up as a split-split-plot block design with four replications. The maize hybrid ZP388 was planted, and a standard and a slow-release form of urea were applied. For each N source, maize was grown at two row spacings: narrow of 50 cm, and standard of 70 cm, while weed control treatments included: C - without herbicide application, T - application of a pre-emergence mix of herbicides. Sowing was done in the second decade of April, 2014, 2015 and 2016. Six weeks after herbicide application, the fresh biomass of weeds uprooted from 1 m2 and aboveground biomass of ten crop plants per plot were measured together with dry matter after drying in a laboratory oven. Water content (% in weed and maize plants was calculated as a relation between fresh and dry biomass. Maize yield was measured at the end of each growing season and calculated with 14% of moisture. All data were processed by ANOVA. The fresh and dry biomass of weeds were significantly (P>0.05 higher in untreated control than in the treated variant, while differences in water content were not significant between the two treatments. Row spacing and urea form did not cause significant differences in weed parameters. Related to this, maize fresh and dry biomass, as well as water content, were higher in herbicide-treated variants than in control but differences were insignificant. Maize biomass was somewhat higher in 50 cm rows and after application of the slow-release urea fertilizer. Yield was higher from 70 cm rows and after application of

  14. Adubação e o período anterior à interferência das plantas daninhas na cultura do amendoim Effect of fertilization on weeds and on the period before weed interference in the peanut culture

    Directory of Open Access Journals (Sweden)

    M.S. Yamauti

    2010-01-01

    area, but without particularly affecting the dry mass accumulated by these species. Peanut can grow along with the weed community, with and without fertilization, up to 15 and 17 DAE, without significant yield losses. Weed interference reduced peanut productivity between 31 and 34% for both the fertilized area and the area without fertilization, respectively.

  15. Integrated weed management in wheat

    International Nuclear Information System (INIS)

    Marwat, K.B.; Khan, M.A.; Nawab, K.; Khattak, A.M.

    2011-01-01

    The paper summarizes the results of an experiment conducted on wheat at Kohat, Khyber Pakhtunkhwa, Pakistan during winter 2004-05. Randomized complete block design with split-split-plot arrangement was used where wheat line and broadcast sowing were kept in main plots. Seed rates (100 and 150 kg ha-1) were assigned as sub-plots, while four herbicides (Topik, Isoproturon, Puma super and Buctril super) and weed check were assigned to sub-sub-plots. Results revealed that higher biological yield was recorded in line sowing. However, higher wheat seed rate decreased weed biomass and increased biological yield. Herbicides proved to be effective in decreasing weed biomass and enhancing grain yield and its contributing traits. It was suggested that line sowing in combination with higher seeding rate and Buctril super should be used in an integrated weed management fashion. However further studies are required to investigate various ranges of seeding rate and herbicides doses. (author)

  16. A new method to evaluate the weed-suppressing effect of mulches

    DEFF Research Database (Denmark)

    Arentoft, B. W.; Ali, A.; Streibig, Jens Carl

    2013-01-01

    To suppress weeds in an apple (Malus sp.) orchard, we placed spruce (Picea spp.) bark mulch and cocoa (Theobroma cacao) husk mulch for 3 months in thicknesses of 0, 2.5, 5, 10 and 15 cm. To assess the development of weed cover, an innovative use of log-logistic dose–response models was applied...... (ED50 and ED90) differed significantly within and between mulch types. In all except one instance, the cocoa mulch was superior in suppressing weeds. This method was useful for the evaluation, but further research is needed to give a more general conclusion about the suppression ability of the two...

  17. Effecacy of Diffrent Herbicides on Weed Control of Garlic (Allium Sativum

    Directory of Open Access Journals (Sweden)

    M. Hosseni

    2012-04-01

    Full Text Available A field experiment was conducted to evaluate the effect of diffrent herbicides on weeds and garlic in a randomized complete-block design with 12 treatments and three replications, at Siahdasht, Farooj, Khorasan, Iran. Treatments were included rates of 4, 8, 12 and 16 kg.ha-1 Chlorthal-dimethyl (Dacthal, rates of 0.75, 1.5, 3 and 5 lit.ha-1 Oxyfluorfen (Goal, rates of 1, 2, 3 and 6 lit.ha-1 Ioxynil (Totril, and a plot which was hand weeded at the beginning of growing season. Results of three stages sampling showed that weed response to type and amount of herbicide which was significantly (p

  18. Stooped postures are modified by pretask walking in a simulated weed-pulling task.

    Science.gov (United States)

    Hudson, D S; Copeland, J L; Hepburn, C G; Doan, J B

    2014-01-01

    Seasonal agricultural workers are hired in some sectors for intermittent manual weed removal, a stoop and grasp harvesting task likely similar to those associated with the high prevalence of musculoskeletal disorders in agriculture. Evaluation of this task in an experimental situation would be useful for identifying and controlling musculoskeletal injury risks, presuming a valid experimental model of the task can be created. The purpose of the present study was to examine how a relevant work-related task, namely prolonged walking, altered the biomechanics of manual weed removal in a laboratory setting. Preliminary field assessments informed the development and analysis of a simulated manual weed removal with two separate conditions: not primed, where 11 participants (4 female, mean age 21.6 years) manually removed a simulated weed six times, and primed, where 23 participants (13 female, mean age 22.1 years) walked 1600 m prior to manually removing the same simulated weed six successive times. Segment end point markers and experimental motion capture were used to determine hip, knee, and ankle angles, as well as toe-target proximity, during weed removal. Significant differences between primed and not primed participants were found for angular displacement at the ankle (t(32) = 5.08, P weed, leading to decreased trunk flexion during the harvesting task. These findings suggest that priming can positively influence whole-body postures for manual weed removal.

  19. Weed Identification Distribution and Mapping at Njoro and Katumani

    International Nuclear Information System (INIS)

    Mwangi, H; Alembi, D.K

    1999-01-01

    The study was a response to the need from Katumani DFRC and Njoro (NPBC) Crop protection team request for support service in identification of weed spp. in their mandated areas. From their ongoing adaptive research they encountered ceratin weed spp. which were troublesome and they could not identify and their contact farmers had expressed concern over the weed constraint. A survey in the mentioned areas were carried out in the long/short rains 1997. In the fields, the sites were selected after every 10 km. The field selected was traversed and a quadrat measuring 1m 2 was placed randomly and weeds identified. General Position System (GPS) recorded the position. Two methods of identifying weeds thus on the spot in the field in situ and unidentified weed samples were carefully collected, labelled and preserved for identification in the laboratory of NARL herbarium. Weed distribution was determined using scale 1-4 where 1=1 plant/M 2 , 2=2-5 plants/m 2 , 3=6-20 plants/m 2 ,4=>20 plants m /2. The results show identified weeds in different categories; dominant, troublesome, indigenous and weed introduced within the ten years as percieved by farmers. Developed weed maps are presented for specific districts

  20. Vertical distribution and composition of weed seeds within the plough layer after eleven years of contrasting crop rotation and tillage schemes

    DEFF Research Database (Denmark)

    Scherner, Ananda; Melander, Bo; Kudsk, Per

    2016-01-01

    Tillage methods and crop rotation are probably the two most important cropping factors affecting weed communities, particularly when herbicide use is restricted. This study examined weed dynamics following eleven years of different tillage and crop rotation treatments. The aboveground grass weed...... flora was recorded each year and the content and vertical location of individual weed seeds within the plough layer (0–20 cm) were determined after 11 years of continuous mouldboard ploughing (P), pre-sowing tine cultivation to 8–10 cm soil depth (H8-10) and direct drilling (D). The content of weed...... seeds, especially grass weeds, was determined for three distinct soil layers (0–5, 5–10 and 10–20 cm), reflecting the cultivation depths of the tillage treatments. The annual grass weeds, Apera spica-venti and Vulpia myuros, were promoted by non-inversion tillage and in the case of V. myuros also...

  1. WEED CONTROL AND BORON NUTRITION ON Eucalyptus IN SILVOPASTORAL SYSTEM

    Directory of Open Access Journals (Sweden)

    Alexandre Magno Brighenti

    2015-04-01

    Full Text Available The objective of this study was to evaluate the control of weeds in the rows of eucalyptus (Eucalyptus urograndis with herbicides applied singly or combined with boron (B, as well as, the response of Eucalyptus plants to this micronutrient. The experiments were carried out in a split-plot with randomized complete block design, with three replicates. Six treatments were applied to the plots: (i weeded control, (ii control without weeding, (iii glyphosate (1080 g ae ha-1 + chlorimuron-ethyl (10 g ai ha-1 + 0.05% v / v mineral oil, (iv glyphosate (1080 g ae  ha-1 + isoxaflutole (112.5 g ai ha-1,  (v glyphosate (1080 g ae ha-1 and  (vi oxyfluorfen (480 g ai ha-1. The sub-plots consisted of the absence or presence of 4 kg of boric acid (H3BO3 - 17% B in 100 L of water. The addition of boric acid in the solution containing the herbicides did not affect the weed control. There was an increase in boron content in the soil and consequently an increase in the boron levels in the eucalyptus leaves. The combined application of herbicides plus boric acid is perfectly suitable for preventing dry of the pointer on eucalyptus plants. Keywords: Eucalyptus urograndis; chemical control; herbicides; micronutrients; Urochloa decumbens.

  2. Community structure affects annual grass weed invasion during restoration of a shrub-steppe ecosystem

    Science.gov (United States)

    Phil S. Allen; Susan E. Meyer

    2014-01-01

    Ecological restoration of shrub-steppe communities in the western United States is often hampered by invasion of exotic annual grasses during the process. An important question is how to create restored communities that can better resist reinvasion by these weeds. One hypothesis is that communities comprised of species that are functionally similar to the invader will...

  3. Evaluation of Weed Diversity and Modelling Light Interception and Distribution in Multiple and Sole Cropping of Millet (Setaria italica L. and Bean (Phaseolus vulgaris L.

    Directory of Open Access Journals (Sweden)

    A Koocheki

    2013-10-01

    Full Text Available In order to investigate the weed diversity and modeling light interception in sole and intercropping millet and bean an experiment was conducted as complete randomized block design with 4 treatments and 4 replications at the Agricultural Research Station, Ferdowsi University of Mashhad, Iran, during 2008. Treatments included monocultures, intercropping of millet and bean and a control treatment where weeds grew without crops. In this experiment Shannon diversity index and Sorensen similarity index was investigated at six stages. Results indicated that in each stage Shannon index was affected by treatments. In first stage intercropping had the lowest weed diversity but in another stages it has no significant with monocultures. Control treatment has highest weed diversity. For modeling light interception were used INTERCOM model. Results showed that in light interception plant height and leaf distribution was more effective than LAI (Leaf Area Index. Light interception in intercropping was more effective than monoculture.

  4. Phytotoxicity Study on Bidens sulphurea Sch. Bip. as a Preliminary Approach for Weed Control.

    Science.gov (United States)

    da Silva, Bruna P; Nepomuceno, Mariluce P; Varela, Rosa M; Torres, Ascensión; Molinillo, José M G; Alves, Pedro L C A; Macías, Francisco A

    2017-06-28

    Farmers of the Franca region in Brazil observed that Bidens sulphurea was able to eliminate the Panicum maximum weed, which infected coffee plantations, without affecting the crop. In an effort to determine if the inhibitory effects observed were due to the presence of phytotoxic compounds from leaves and roots, a biodirected isolation and spectroscopic characterization has been carried out. The leaf dichloromethane and root acetone extracts were the most active, and the former appeared to be more phytotoxic to the target species, including four weeds. A total of 26 compounds were isolated from leaves and roots, and four of them are described here for the first time. The major compounds in the leaf extract are the sesquiterpene lactones costunolide, reynosin, and santamarine, and these showed marked inhibition. Amaranthus viridis and Panicum maximum were the most sensitive species of the weeds tested. These three phytotoxic lactones were also evaluated on A. viridis and P. maximum under hydroponic conditions. A. viridis was the most affected species with the three lactones, and santamarine was the most phytotoxic compound on both. This is the first time that the phytotoxicity of sesquiterpene lactones has been evaluated on hydroponic culture. The work described here is a preliminary approach for the use of B. sulphurea for weed control in agriculture, both as a cover crop and by use of its components as natural herbicide leads.

  5. Efficacy of Maister OD (Foramsulfuron + Idosulfuron a New Herbicide in Controlling Weeds of Corn Fields

    Directory of Open Access Journals (Sweden)

    J. Abdi

    2012-07-01

    Full Text Available To evaluate the efficacy of a new herbicide Foramsulfuron +Idosulfuron (Maister OD against other herbicides in corn fields, this experiment was fulfielld in 2010 at Mahidasht, Research Center of Agriculture and Natural Resources of Kermanshah, Iran. It was concucted in randomized complete block design with four replications and 11 treatments. In this experiment, three doses of herbicides (38.75, 46.5 and 54.25 g/ha including foramsulfuron + idosulfuron along with Nicusulfuron, ForamSulfuron, Rimsulfuron, Foramsulfuron + Rimsulfuron , Bromicid + hand weeding narrow leaf weeds, Bromicid + Nicusulfuron and U46 + hand weeding of narrow leaf weeds and a complete weeding as the control treatments were investigated. Weeds present in the field were Xanthium stromarium,Chenopedium album, Portulaca oleracea, Sorgum halepense and Setaria virdis. The results of this study showed that doses 38.75 and 46.5 g/ha of herbicide foramsulfuron + idosulfuron after treatments of Bromicid + Nicusulfuron and, Bromicid + narrow leaf weed, hand weeding respectively could control 90 and 86 % of weeds in corn field and increase its yields significantly. Because there are presently few registered herbicide available in Iran, necessity of finding proper herbicides to control weeds in corn field and based on the results oblained from this experiment it seems using 46.5 and 38-75 grams per hectare respectively of foramsulfuron + idosulfuron could be a better option than other herbicides to control weeds in corn fields and increase its seed yield.

  6. Descriptive and mechanistic models of crop–weed competition

    NARCIS (Netherlands)

    Bastiaans, L.; Storkey, J.

    2017-01-01

    Crop-weed competitive relations are an important element of agroecosystems. Quantifying and understanding them helps to design appropriate weed management at operational, tactical and strategic level. This chapter presents and discusses simple descriptive and more mechanistic models for crop-weed

  7. A combined flamer-cultivator for weed control during the harvesting season of asparagus green spears

    Energy Technology Data Exchange (ETDEWEB)

    Martelloni, L.; Fontanelli, M.; Frasconi, C.; Raffaelli, M.; Pirchio, M.; Peruzzi, A.

    2017-07-01

    Weed competition during spears harvesting reduces asparagus yields. The application of herbicides during this period is illegal, and alternative non-chemical practices are needed. This research tested the effectiveness and efficiency of a custom-built combined flamer-cultivator to control weeds (both in the inter- and intra- spears production bands) during the spears harvest season. It also analysed the effects of various liquefied petroleum gas (LPG) doses on total asparagus yield, mean spear weight, and total number of marketable spears. In both years, the asparagus spears were generally not damaged by flame weeding using LPG doses of between 43 to 87 kg/ha. The same LPG doses were effective in controlling weeds, showing the same total marketable yields as the weed-free control. At high LPG doses (e.g. 130 and 260 kg/ha), yields decreased as a consequence of the damage caused to the spears, resulting in a lower number of marketable spears. Flaming did not affect the mean spear weight, and can be applied repeatedly during harvesting to maintain the weeds at a level that does not lead to a yield reduction. The repeated use of the combined flamer-cultivator (every seven days) led to higher yields than plots where weed control was not conducted. The new machine can be used in a period when herbicides are not possible. Flaming could be introduced by asparagus producers as an alternative, or in addition to herbicides applied in the pre-emergence and post-harvest of spears.

  8. A combined flamer-cultivator for weed control during the harvesting season of asparagus green spears

    International Nuclear Information System (INIS)

    Martelloni, L.; Fontanelli, M.; Frasconi, C.; Raffaelli, M.; Pirchio, M.; Peruzzi, A.

    2017-01-01

    Weed competition during spears harvesting reduces asparagus yields. The application of herbicides during this period is illegal, and alternative non-chemical practices are needed. This research tested the effectiveness and efficiency of a custom-built combined flamer-cultivator to control weeds (both in the inter- and intra- spears production bands) during the spears harvest season. It also analysed the effects of various liquefied petroleum gas (LPG) doses on total asparagus yield, mean spear weight, and total number of marketable spears. In both years, the asparagus spears were generally not damaged by flame weeding using LPG doses of between 43 to 87 kg/ha. The same LPG doses were effective in controlling weeds, showing the same total marketable yields as the weed-free control. At high LPG doses (e.g. 130 and 260 kg/ha), yields decreased as a consequence of the damage caused to the spears, resulting in a lower number of marketable spears. Flaming did not affect the mean spear weight, and can be applied repeatedly during harvesting to maintain the weeds at a level that does not lead to a yield reduction. The repeated use of the combined flamer-cultivator (every seven days) led to higher yields than plots where weed control was not conducted. The new machine can be used in a period when herbicides are not possible. Flaming could be introduced by asparagus producers as an alternative, or in addition to herbicides applied in the pre-emergence and post-harvest of spears.

  9. Occurence, spread and possibilities of invasive weeds control in sugar beet

    Directory of Open Access Journals (Sweden)

    Konstantinović Branko I.

    2006-01-01

    Full Text Available Floristically rich and diverse weed comunity of sugar beet is in our country represented by 150 weed species. They are not all equaly significant in weediness of this crop. Only a limited number of them participate in weed comunity composition. These are: Abuthilon theophrasti Medic., Ambrosia artemisiifolia L., Amaranthus retroflexus L., Chenopodium album L., Cirsium arvense (L Scop., Convolvulus arvensis L., Cynodon dactylon (L Pers. Digitaria sanguinalis (L Scop., Hibiscus trionum L., Rubus caesius L. Echinochloa crus-gall L., Polygonum aviculare L., P. lapathifolium L., P. persicaria L., Setaria glauca (L P. B., S. viridis (L P. B., Solanum nigrum L. and Sorghum halepense (L Pers. In shooting period up to 4-8 weeks upon emergence, sugar beet is under the haviest harmfull inluence of weeds, especially invasive ones such as: Abuthilon theophrasti Medic. Ambrosia artemisiifolia L., Cirsium arvense (L Scop., Iva xanthifolia L. Sorghum halepense (L Pers. and Xanthium strumarium L. Sugar beet growing requires intensive cultural practices, i.e. basic and additional tillage and cultivation. Due to the widening of weed problems, frequent herbicide use in several applications is needed in the longer time period.

  10. 7 CFR 201.50 - Weed seed.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or... sieve are considered weed seeds. For wild onion and wild garlic (Allium spp.) bulblets classed as inert...

  11. Shorth-Term Impacts of Weed Cutting on the Physical Habitats in Lowland Rivers

    DEFF Research Database (Denmark)

    Pedersen, Morten Lauge; Baattrup-Pedersen, Annette; Rørth, Frederikke Rahbek

    2011-01-01

    We studied the effects of weed cutting at 3 reaches in two Danish lowland rivers with the objectives of examining the response to cutting in rivers with contrasting physical conditions, macrophyte diversity, and assemblage patterns. Physical characteristics and abundance of macrophyte species were...... registered 3 or 4 times throughout the study period on all reaches. Weed cutting did not affect the total coverage of stone, gravel and sand and substratum homogeneity, and no common response was found among the reaches. This result is likely to reflect both initial differences in the physical environment...

  12. Assessment of Corn Densities on Ecological Indices of Weed Species

    Directory of Open Access Journals (Sweden)

    G Mahmoodi

    2012-06-01

    Full Text Available Diversity, dominance, and stability of weeds are the most important ecological properties in agricultural systems, which influenced by management factors such as crop density, abundantly. This experiment was conducted in 2009 at Ferdowsi University of Mashhad Research Field. The experimental design was interval mapping with four levels of corn densities (5, 6, 7 and 9 plant.m-2 and four levels of weed control (full-control, without control, broad-leaves control and grasses control. Weed sampling was done at 3 stages included beginning and end of critical period weed control and harvesting time. The results showed that the effect of plant density on species diversity was significant; some how the amount of Shanon and Simpson Indices were lowest in the 9 plant.m-2 (0.39 and 0.45, respectively and greatest in 5 plant.m-2 (0.84. The results also showed that the maximum amount of dominance index was observed in 9 plant.m-2, that was seen in Echinochloa crus- galli and Convulvulus arvensis at the beginning of growing season, then in Solanum nigrum and Amaranthus retroflexus in the end of growing season. The amount of community dominance index in 9 plant.m-2 was higher than other densities, and it decreased with decline of densities. based on the results of present experiment the linear relationship between plant species and area was found. The calculated amount of Alpha and Beta diversities. in a θ and β scales based on coefficients of this relationship were 0.534 (four species per unit area and 0.29 (two species per unit area, respectively. In conclusion the result of this experiment pointed that the weeds diversity decreased with increasing of corn density, weed diversity decreased and therefore, having appropriate plant density is very efficient for sustainable weed management.

  13. Configuration and specifications of an Unmanned Aerial Vehicle (UAV for early site specific weed management.

    Directory of Open Access Journals (Sweden)

    Jorge Torres-Sánchez

    Full Text Available A new aerial platform has risen recently for image acquisition, the Unmanned Aerial Vehicle (UAV. This article describes the technical specifications and configuration of a UAV used to capture remote images for early season site- specific weed management (ESSWM. Image spatial and spectral properties required for weed seedling discrimination were also evaluated. Two different sensors, a still visible camera and a six-band multispectral camera, and three flight altitudes (30, 60 and 100 m were tested over a naturally infested sunflower field. The main phases of the UAV workflow were the following: 1 mission planning, 2 UAV flight and image acquisition, and 3 image pre-processing. Three different aspects were needed to plan the route: flight area, camera specifications and UAV tasks. The pre-processing phase included the correct alignment of the six bands of the multispectral imagery and the orthorectification and mosaicking of the individual images captured in each flight. The image pixel size, area covered by each image and flight timing were very sensitive to flight altitude. At a lower altitude, the UAV captured images of finer spatial resolution, although the number of images needed to cover the whole field may be a limiting factor due to the energy required for a greater flight length and computational requirements for the further mosaicking process. Spectral differences between weeds, crop and bare soil were significant in the vegetation indices studied (Excess Green Index, Normalised Green-Red Difference Index and Normalised Difference Vegetation Index, mainly at a 30 m altitude. However, greater spectral separability was obtained between vegetation and bare soil with the index NDVI. These results suggest that an agreement among spectral and spatial resolutions is needed to optimise the flight mission according to every agronomical objective as affected by the size of the smaller object to be discriminated (weed plants or weed patches.

  14. Configuration and specifications of an Unmanned Aerial Vehicle (UAV) for early site specific weed management.

    Science.gov (United States)

    Torres-Sánchez, Jorge; López-Granados, Francisca; De Castro, Ana Isabel; Peña-Barragán, José Manuel

    2013-01-01

    A new aerial platform has risen recently for image acquisition, the Unmanned Aerial Vehicle (UAV). This article describes the technical specifications and configuration of a UAV used to capture remote images for early season site- specific weed management (ESSWM). Image spatial and spectral properties required for weed seedling discrimination were also evaluated. Two different sensors, a still visible camera and a six-band multispectral camera, and three flight altitudes (30, 60 and 100 m) were tested over a naturally infested sunflower field. The main phases of the UAV workflow were the following: 1) mission planning, 2) UAV flight and image acquisition, and 3) image pre-processing. Three different aspects were needed to plan the route: flight area, camera specifications and UAV tasks. The pre-processing phase included the correct alignment of the six bands of the multispectral imagery and the orthorectification and mosaicking of the individual images captured in each flight. The image pixel size, area covered by each image and flight timing were very sensitive to flight altitude. At a lower altitude, the UAV captured images of finer spatial resolution, although the number of images needed to cover the whole field may be a limiting factor due to the energy required for a greater flight length and computational requirements for the further mosaicking process. Spectral differences between weeds, crop and bare soil were significant in the vegetation indices studied (Excess Green Index, Normalised Green-Red Difference Index and Normalised Difference Vegetation Index), mainly at a 30 m altitude. However, greater spectral separability was obtained between vegetation and bare soil with the index NDVI. These results suggest that an agreement among spectral and spatial resolutions is needed to optimise the flight mission according to every agronomical objective as affected by the size of the smaller object to be discriminated (weed plants or weed patches).

  15. Weed Control in Clean Agriculture: A Review1

    OpenAIRE

    ABOUZIENA,H.F.; HAGGAG,W.M.

    2016-01-01

    ABSTRACT Weed control is consider the major obstacle for the growers in the organic farming. Lower plant productivity in organic farming mainly related to the poor weed control. It is widely known, in most cases, that losses caused by weeds exceeded the losses from any category of agricultural pests. Under water-stress condition, weeds can reduce crop yields more than 50% through moisture competition alone. In the light of the environmental and toxicological problems created by herbicides, it...

  16. Residues and accumulation of molinate in rice crops and aquatic weeds in the MUDA rice agroecosystem

    International Nuclear Information System (INIS)

    Nashriyah Mat; Sabri Junoh; Nuriati Nurdin; Ramli Ishak

    2002-01-01

    Plant and soil residue levels and its accumulation in rice crops and rice aquatic weed plants were studied. Molinate residue levels in rice, weeds and soil were not significantly different between the recycled and the non-recycled area, even though they were higher in the non-recycled area. In the rice plant, the residue level at 10 DAT (days after treatment) was significantly higher than 30 DAT in the recycled area. In rice aquatic weed plants, the residue level was significantly higher at 10 DAT as compared to 30 DAT in the non-recycled area. Molinate residue levels in soil at 10 DAT and 30 DAT were similar. Molinate accumulated (ratio of molinate concentration in plant over soil) more in the rice crop as compared to rice aquatic weeds at 10 DAT, in both the recycled and the non-recycled areas. (Author)

  17. Gibberellic and kaurenoic hybrid strigolactone mimics for seed germination of parasitic weeds.

    Science.gov (United States)

    Pereira, Rondinelle G; Cala, Antonio; Fernández-Aparicio, Mónica; Molinillo, José Mg; Boaventura, Maria Ad; Macías, Francisco A

    2017-12-01

    Parasitic weeds are widespread and cause significant losses in important crops. Their germination requires the detection of crop-derived molecules such as strigolactones. Strigolactone mimics are germination-inducing molecules with the potential to apply a suicidal germination strategy for seed bank control of parasitic weeds. The D-ring, which is instrumental in the germination process of seeds of parasitic weeds, was attached to gibberellin (GA 3 ) and kaurenoic acid as the scaffold. It was shown that indeed strigolactone mimics prepared from GA 3 and kaurenoic acid are active as stimulants when a D-ring is present; some of the mimics are as active as GR24. The starting molecules were plant hormones that had previous growth-regulating activity in other organisms and the products showed enhanced activity towards parasitic weeds. The information generated may contribute to a better understanding of the germination biochemistry of the weed species used. Further research is required in this area but it is clear that the results are promising. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  18. Simulating changes in cropping practices in conventional and glyphosate-resistant maize. II. Weed impacts on crop production and biodiversity.

    Science.gov (United States)

    Colbach, Nathalie; Darmency, Henri; Fernier, Alice; Granger, Sylvie; Le Corre, Valérie; Messéan, Antoine

    2017-05-01

    Overreliance on the same herbicide mode of action leads to the spread of resistant weeds, which cancels the advantages of herbicide-tolerant (HT) crops. Here, the objective was to quantify, with simulations, the impact of glyphosate-resistant (GR) weeds on crop production and weed-related wild biodiversity in HT maize-based cropping systems differing in terms of management practices. We (1) simulated current conventional and probable HT cropping systems in two European regions, Aquitaine and Catalonia, with the weed dynamics model FLORSYS; (2) quantified how much the presence of GR weeds contributed to weed impacts on crop production and biodiversity; (3) determined the effect of cultural practices on the impact of GR weeds and (4) identified which species traits most influence weed-impact indicators. The simulation study showed that during the analysed 28 years, the advent of glyphosate resistance had little effect on plant biodiversity. Glyphosate-susceptible populations and species were replaced by GR ones. Including GR weeds only affected functional biodiversity (food offer for birds, bees and carabids) and weed harmfulness when weed effect was initially low; when weed effect was initially high, including GR weeds had little effect. The GR effect also depended on cultural practices, e.g. GR weeds were most detrimental for species equitability when maize was sown late. Species traits most harmful for crop production and most beneficial for biodiversity were identified, using RLQ analyses. None of the species presenting these traits belonged to a family for which glyphosate resistance was reported. An advice table was built; the effects of cultural practices on crop production and biodiversity were synthesized, explained, quantified and ranked, and the optimal choices for each management technique were identified.

  19. Bioenergy potential of eight common aquatic weeds

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, S.A.; Nipaney, P.C.; Schaumberg, G.D. (Pondicherry (Central) Univ. (IN). Salim Ali School of Ecology)

    1990-01-01

    Eight common aquatic weeds Salvinia molesta, Hydrilla verticillata, Nymphaea stellata, Azolla pinnata, Ceratopteris sp. Scirpus sp. Cyperus sp, and Utricularia reticulata were digested anaerobically to produce methane. The carbon to nitrogen (C/N) ratio, carbon to phosphorus (C/P) ratio, and the volatile solids (VS) content of the weeds varied widely. No trend between these factors and the methane yield was discernable; the possible reasons are discussed. The energy potential of the weeds per unit area of the weed crop was worked out. Natural stands of salvinia, such as the one employed in the present investigation, would yield energy (methane) of the order of 10{sup 8} Kcal/ha/yr. (author).

  20. A STUDY ON WEED CONTROL IN SOYBEAN

    Directory of Open Access Journals (Sweden)

    S. TJITROSEMITO

    1991-01-01

    Full Text Available Two field experiments on weed control in soybeans were carried out at BIOTROP, Bogor, Indonesia from February to June, 1989. The critical period for weed control was found to be between 20 - 40 days after planting of soybean (c. v. Wilis grown at a planting distance of 40 x 10 cm. It did not coincide with the fastest growth in terms of trifoliate leaf number. Further studies were suggested to understand the physiological growth of soybean related to weed control. Pendimethalin at 660- 1320 g a.e./ha applied one day after sowing did not cause any phytotoxic effect to soybean and had good weed control performance.

  1. Conservation implications of weed management of lake reservoirs ...

    African Journals Online (AJOL)

    Management of weeds around lake reservoirs is often implemented to reduce any possibility of siltation. However, machineries used in weed management have resulted in habitat degradation and geometrical multiplication of weeds by chopping rhizomes and scattering seeds. In general, the removal offers some feedbacks ...

  2. WHITE BLISTER SPECIES (Albuginaceae ON WEEDS

    Directory of Open Access Journals (Sweden)

    Karolina Vrandečić

    2011-06-01

    Full Text Available The obligate fungi inside the family Albuginaceae are widespread world wide and cause white rust or white blister disease. Mycopopulation of weeds has been researched within the project „The role of weeds in epidemiology of row-crop diseases“. The aim of this research was to identify white blister species occurring on weeds in Eastern Croatia. Weed plants with disease symptoms characteristic for white blister species have been collected since 2001 on location Slavonia and Baranja country. Determination of white blister species was based on morphological characters of pathogen and the host. Wilsoniana bliti was determined on Amaranthus retroflexus and Amaranthus hybridus leaves. Capsella bursa pastoris is a host for Albugo candida. Ambrosia artemisiifolia is a host for Pustula sp. and Cirsium arvense was found to be host for Pustula spinulosa. Wilsoniana portulaceae was determined on Portulaca oleracea.

  3. Impact of fungicides on weed growth

    Directory of Open Access Journals (Sweden)

    Nordmeyer, Henning

    2014-02-01

    Full Text Available The study has shown that fungicides influence the growth of weeds. The competition against crops will be substantially reduced. Bioassays in a climate chamber variation in temperature as well as different lightning phases and microplot trials under semi field levels were carried out to investigate the influence of fungicides on weed growth. Selected weed species (Alopecurus myosuroides, Viola arvensis, Galium aparine, Stellaria media, Lamium purpureum have been examined with different dose rates of fungicides (Adexar, Bravo 500, Diamant, Crupozin flüssig. Weed species showed a different sensitivity. There were leaf discoloration, contractions and growth inhibition. In some cases using common practise dose rates of fungicides more than 70% growth inhibition could be estimated 14 days after application in comparison to the untreated control. Effects were much stronger in bioassays than in semi field trials.

  4. Guidelines for management of noxious weeds at Hanford

    International Nuclear Information System (INIS)

    Roos, R.C.; Malady, M.B.

    1995-01-01

    Integrated Pest Management Services is responsible for management and control of noxious weeds on the Hanford Site. Weed species and populations are prioritized and objective defined, according to potential site and regional impact. Population controls are implemented according to priority. An integrated approach is planned for noxious weed control in which several management options are considered and implemented separately or in coordination to best meet management objectives. Noxious weeds are inventories and monitored to provide information for planning and program review

  5. Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize.

    Science.gov (United States)

    Jordaan, E M; De Waele, D

    1988-10-01

    The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae.

  6. Adensamento da beterraba no manejo de plantas daninhas Increased beet density in weed management

    Directory of Open Access Journals (Sweden)

    L.B. Carvalho

    2008-03-01

    weedy and weed-free periods, respectively. The critical period of weed interference prevention was shorter for increased beet density (11 days than for 40 plants m-2 beet density (22 days. Thus, increased beet density increased beet plant capacity to suppress weeds. Thus, weed growth and time and extension of weed interference critical periods were affected. Increased beet density can be used as an efficient tool for weed management.

  7. Effect of simplified tillage and mineral fertilization on weed infestation of potato growing on loess soil

    Directory of Open Access Journals (Sweden)

    Karol Bujak

    2012-12-01

    Full Text Available In the paper effect of limitation of postharvest measure to single cultivating or disking of soil and mineral fertilization level on number, air-dry matter and botanical composition of weeds in the potato-field is presented. Simplifield postharvest measure was increasing insignificantly and more intensive fertilization was limiting the weed infestation of potato-field. Decteasing of weeds number increasing fertilization was ststistically significant. Dominating species of weeds in the potato-field were Capsella bursa-pastoris, Poa annua, Viola arvensis, Chenopodium album, Elymus repens i Equisetum arvense.

  8. Crop characteristics and weed Interactions of diverse Rrecurrent Inbred Lines (RILs) from a weed-suppressive x non-suppressive rice mapping population

    Science.gov (United States)

    ndica rice genotypes with enhanced weed suppression traits have been previously identified as potentially useful in supplementing weed control efforts in drill-seeded systems in the southern USA. A particularly weed-suppressive indica genotype (PI 312777) that was also high tillering and high yield...

  9. Weed seed germination in winter cereals under contrasting tillage systems

    DEFF Research Database (Denmark)

    Scherner, Ananda

    2015-01-01

    to accumulate in the top soil layer and timing of herbicide applications sometimes seems to target the emergence pattern of these weeds poorly. In contrast to the management of most diseases and pests, weed management should be considered in a time frame. The abilities to produce above and below ground...... of weeds. An important component in IWM is to understand and ultimately predict weed emergence patterns in relation to the cropping system and the tillage method applied. A better understanding of the cumulative emergence patterns of weed species in winter crops under different tillage regimes will help......Grass weeds and Gallium aparine are major weed problems in North European arable cropping systems with high proportions of winter crops, especially winter wheat (Clarke et al., 2000; Melander et al., 2008). Problems are accentuated where inverting tillage is omitted, as weed seeds tend...

  10. Allelopathy of weed extracts on yield and its components in four cultivars of rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Ali MOHADESI

    2011-07-01

    Full Text Available Weeds are enemies to the crop plants and have harmful effects on agricultural crops due to several factors such as competition for space, light and nutrients. Allelopathic effects of weed extracts were studied on grain yield and yield components of rice. The experiment was carried out in the Rice Research Institute of Chaparsar, in 2006- 2007, in Tonekabon, Iran (latitude 36°54’ N, longitude 50° 40’E, level -20 m altitude, split plot on basis of randomized completely block design (RCBD with 4 replications. Results showed highly significant differences suggesting substantial to moderate phenotypic variability in most parameters evaluated except number of empty grain and 1000 -grain weight. Also, most yield of single plant obtained from umbrella sedge extract (28.5 g. It seems that umbrella sedge had least minerals in water; it could be affected positively on important factors such as yield of single plant compared to other treatments. Correlation coefficient analysis revealed significant and negative correlation between number of empty grain and yield of single plant (r=-0.42***. It’s implies that grain yield magnitude of Nemat cultivar exhibiting the least number of empty grain. Although yield of single plant was not affected neither by plant height nor number of tiller. In addition, irrigation water due to existence of high mineral and chemical pesticides in upstream of station farms severely was reduced yield. Also, results of this research showed that weed extracts haven’t very allelopathic effect on rice and in end of growing season, that’s better, plant leftover return and remain in field.

  11. Evaluation of weed control methods on sugar beet (Beta vulgaris L. yield at different levels of nitrogen

    Directory of Open Access Journals (Sweden)

    AliAsghar Chitband

    2017-03-01

    Full Text Available Introduction: Weed competition is one of the major factors which limit sugar beet production in the world. Weed – crop interactions are based on competition for water, nutrients and light and allelopathic effects may also play a small role. In sugar beet weed interference, all these factors are important too, but the light is of prime importance. Due to the fact that a lot of weeds can grow above the sugar beet canopy and reduce the amount of photosynthetic radiation reaching the crop, these weeds are stronger competitors compared to smaller weeds. In much sugar beet growing areas dicot weeds of the families Chenopodiaceae, Asteraceae, Brassicaceae and Polygonaceae are of major importance. The monocots are less important compared to dicot weeds. Competition from uncontrolled annual weeds that emerge within 8 weeks of sowing or within 4 weeks of the crop reaching the two-leaf stage can reduce root yields by 26–100% .Weeds that emerge 8 weeks after sowing, and particularly after the sugar beet plants have eight or more leaves, are less likely to affect yield. Although tractor hoeing and hand labour are still used in many production areas, herbicides have been the primary method of weed control in sugar beet. The effectiveness of pre-emergence residual herbicides decreases with reductions in rainfall or soil wet content. Therefore, less than 10 % of the total sugar beet crop is treated with pre-emergence herbicides. The remaining 90 % depends solely on a selection of post-emergence herbicides to maintain season-long weed control. The major herbicides are phenmedipham, chloridazon, metamitron. Mixtures of post-emergence, broad spectrum herbicides have to be applied to control the wide range of weed species in sugar beet crops. Materials and Methods: To study the effects of weeds control by hand weeding and herbicides combination with two selective herbicides at different levels of nitrogen application on sugar beet yield and quality

  12. Weed flora in organically grown spring cereals in Finland

    Directory of Open Access Journals (Sweden)

    J. SALONEN

    2008-12-01

    Full Text Available The weed flora in organically grown spring cereals was investigated in southern and central Finland in 1997-1999 with the primary purpose of determining the species composition and the level of weed infestation. Altogether 165 fields were surveyed in the middle of the growing season. A total of 126 weed species were found, of which 42 exceeded the frequency level of 10%. The most frequent weed species were Chenopodium album, Stellaria media, Galeopsis spp. and Viola arvensis. Elymus repens was the most frequent grass species. The average density of weeds was 469 plants m-2 (median 395, and the air-dry biomass was 678 kg ha-1 (median 567 which accounted for 17% of the total biomass of the crop stand. Infestation by Chenopodium album and the perennial species Elymus repens, Cirsium arvense and Sonchus arvensis is of major concern. Weed control strategies should include direct control measures to overcome weed problems related to the conversion period from conventional to organic growing.

  13. Acute poisoning in cattle due to ingestion of rattlebox weed in ...

    African Journals Online (AJOL)

    A case of poisoning due to ingestion of Crotalaria cylindrocapa otherwise referred to as rattlebox weed in cattle was investigated and reported in this paper. High morbidity and low mortality rates were recorded in the affected cattle. Clinical signs observed were; hypersalivation, weakness, ataxia, inappetance , recumbency ...

  14. Weeds as important vegetables for farmers

    NARCIS (Netherlands)

    Cruz Garcia, G.S.; Price, L.L.

    2012-01-01

    The objective of this study was to investigate the multiple uses and cognitive importance of edible weeds in Northeast Thailand. Research methods included focus group discussions and freelistings. A total of 43 weeds consumed as vegetable were reported, including economic, naturalized, agricultural

  15. Development of Weeds Density Evaluation System Based on RGB Sensor

    Science.gov (United States)

    Solahudin, M.; Slamet, W.; Wahyu, W.

    2018-05-01

    Weeds are plant competitors which potentially reduce the yields due to competition for sunlight, water and soil nutrients. Recently, for chemical-based weed control, site-specific weed management that accommodates spatial and temporal diversity of weeds attack in determining the appropriate dose of herbicide based on Variable Rate Technology (VRT) is preferable than traditional approach with single dose herbicide application. In such application, determination of the level of weed density is an important task. Several methods have been studied to evaluate the density of weed attack. The objective of this study is to develop a system that is able to evaluate weed density based on RGB (Red, Green, and Blue) sensors. RGB sensor was used to acquire the RGB values of the surface of the field. An artificial neural network (ANN) model was then used for determining the weed density. In this study the ANN model was trained with 280 training data (70%), 60 validation data (15%), and 60 testing data (15%). Based on the field test, using the proposed method the weed density could be evaluated with an accuracy of 83.75%.

  16. Organic and weed control in water supply reservoirs of power plants

    International Nuclear Information System (INIS)

    Eswaran, M.S.

    2000-01-01

    Aquatic weeds and algal control in water supply reservoirs used for multipurpose use need specific attention, since they pose a lot of problem for the operating plants by affecting (a) the water quality of boiler and feed waters, (b) the performance of DM plants by reducing the efficiency of Anion beds, (c) the performance of Activated Carbon Filters (ACF) and (d) fouling induced corrosion problems in cooling water systems (Heat Exchangers and Piping materials) causing plant outages leading to production losses. The photosynthetic activity of planktonic plants which are growing abundantly in the open reservoir, sustained by the relatively high inorganic phosphate levels shoots up the pH of the reservoir water to very high levels. High pH, Total Dissolved Solids (TDS) and depleted plants can increase corrosion problems affecting plant performance. This paper focuses on the type of weeds prominent in the water supply reservoir at Kalpakkam and the associated problems in the Nuclear Power Plants (NPPs). (author)

  17. Research on the weed control degree and glyphosate soil biodegradation in apple plantations (Pioneer variety

    Directory of Open Access Journals (Sweden)

    Ersilia ALEXA

    2010-05-01

    Full Text Available In this study we follow control degree of glyphosate herbicide on weeds in apple plantations (Pioneer variety of the Research Station Timisoara. It was also followed glyphosate biodegradation capacity in the soil by determining the amount of CO2 released by the action of microorganisms on C14 glyphosate marked isotope. Laboratory analysis of glyphosate residues in soil was made using a Liquid Scintillation TRIATHLER. Glyphosate biodegradation ability in the presence of soil microorganisms is high, so glyphosate residues remaining in soil, in terms of its use in weed combating, are minimal. Study of glyphosate biodegradation capacity in the experimental field indicates that the CO2 fraction accumulated after 50 days is 28.02% for samples exposed in the experimental field. Weather conditions, especially temperature variations between day and night, influences the activity of soilmicroorganisms and affect biodegraded glyphosate percentage.Chemical method of weed control consisted in: herbicide used was Roundup 3 l/ha (glyphosate isopropyl amine salt 360 g/l and are based on chemical application on weeds, on the rows of trees, on their uptake and translocation in their organs having as principal scope the total destruction of weeds. The experimental results obtained reveal a weed combat degree of 82.98% , in the case of chemical variant, compared with control variant. The species combated mainly due to glyphosate herbicide, which is no longer found in the final mapping are: Capsella bursa-pastoris, Chenopodium album, Echinochloa crus-galli, Plantago major, Polygonum aviculare. Total combated weeds /m2 with glyphosate is 126.67.

  18. A combined flamer-cultivator for weed control during the harvesting season of asparagus green spears

    Directory of Open Access Journals (Sweden)

    Luisa Martelloni

    2017-07-01

    Full Text Available Weed competition during spears harvesting reduces asparagus yields. The application of herbicides during this period is illegal, and alternative non-chemical practices are needed. This research tested the effectiveness and efficiency of a custom-built combined flamer-cultivator to control weeds (both in the inter- and intra- spears production bands during the spears harvest season. It also analysed the effects of various liquefied petroleum gas (LPG doses on total asparagus yield, mean spear weight, and total number of marketable spears. In both years, the asparagus spears were generally not damaged by flame weeding using LPG doses of between 43 to 87 kg/ha. The same LPG doses were effective in controlling weeds, showing the same total marketable yields as the weed-free control. At high LPG doses (e.g. 130 and 260 kg/ha, yields decreased as a consequence of the damage caused to the spears, resulting in a lower number of marketable spears. Flaming did not affect the mean spear weight, and can be applied repeatedly during harvesting to maintain the weeds at a level that does not lead to a yield reduction. The repeated use of the combined flamer-cultivator (every seven days led to higher yields than plots where weed control was not conducted. The new machine can be used in a period when herbicides are not possible. Flaming could be introduced by asparagus producers as an alternative, or in addition to herbicides applied in the pre-emergence and post-harvest of spears.

  19. Effect of Soybean and Wheat as Cover Crops on Corn Yield and Weed Control using Different Fertilizer Sources

    Directory of Open Access Journals (Sweden)

    F. Dadashi

    2016-02-01

    Full Text Available Introduction: According to the importance of corn in supplying the human food directly and indirectly, it is one of the most important plants among crops. One of the major problems in corn production systems, is competition with weeds that reduce corn yield significantly. Weeds not only reduce crop yields but also decrease the commercial quality and the feeding palatability of main crops. They enhance the soil seed bank of weeds, which may cause continuous weed infestation of field crops as well. Herbicide application is a reliable and highly effective method for weed control. However, demand for safe food products that have been produced with a minimum application of chemical inputs is increasing. Therefore, farmers interested in weed management have to rely on other control approaches. An alternative weed control method is the use of cover crops, which can suppress the growth of weeds by preventing them from light and by producing allelopathic compounds. Cover crops successfully have been integrated into conservational agriculture systems in many areas of the world. Legumes are used as cover crop because of their rapid growth, in addition their potential to provide further nitrogen,along with high ability to compete with weeds. Materials and Methods: In order to study the effect of cover crops (soybean and wheat and different fertilizers sources on yield of corn and weed control, a filed experiment was conducted in randomized complete block design with three replications in 2012. Treatments included two cover crop (wheat and soybean and three fertilizer (no fertilizer, chemical fertilizer and compost..Fertilizer treatments was used according to soil analysis and requirement of corn (as a main plant. Weed-infestation and weed-free plots were used as controls. Study cultivars of corn, wheat and soybean were NS-640, Milan and Sari, respectively. Planting of corn was in June and cover crop was planted with corn simultaneously and between corn rows

  20. Mechanical weed control in organic winter wheat

    Directory of Open Access Journals (Sweden)

    Euro Pannacci

    2017-12-01

    Full Text Available Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006- 07; exp. 3, 2007-08 in central Italy (42°57’ N - 12°22’ E, 165 m a.s.l. in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: i spring tine harrowing used at three different application times (1 passage at T1, 2 passages at the time T1, 1 passage at T1 followed by 1 passage at T1 + 14 days in the crop sowed at narrow (traditional row spacing (0.15 m; and ii split-hoeing and finger-weeder, alone and combined at T1, in the crop sowed at wider row spacing (0.30 m. At the time T1 winter wheat was at tillering and weeds were at the cotyledons-2 true leaves growth stage. The experimental design was a randomized block with four replicates. Six weeks after mechanical treatments, weed ground cover (% was rated visually using the Braun-Blanquet coverabundance scale; weeds on three squares (0.6×0.5 m each one per plot were collected, counted, weighed, dried in oven at 105°C to determine weed density and weed above-ground dry biomass. At harvest, wheat ears density, grain yield, weight of 1000 seeds and hectolitre weight were recorded. Total weed flora was quite different in the three experiments. The main weed species were: Polygonum aviculare L. (exp. 1 and 2, Fallopia convolvulus (L. Á. Löve (exp. 1 and 3, Stachys annua (L. L. (exp. 1, Anagallis arvensis L. (exp. 2, Papaver rhoeas L. (exp.3, Veronica hederifolia L. (exp. 3. In the winter wheat sowed at narrow rows, 2 passages with spring-tine harrowing at the same time seems to be the best option in order to reconcile a good efficacy with the feasibility of treatment. In wider rows spacing the best weed control was obtained by split hoeing alone or combined with finger-weeder. The grain yield, on average 10% higher in narrow rows, the lower costs and the good selectivity of spring-tine harrowing

  1. Weed infestation of a winter wheat canopy under the conditions of application of different herbicide doses and foliar fertilization

    Directory of Open Access Journals (Sweden)

    Piotr Kraska

    2012-12-01

    control treatment were significantly higher in comparison with the herbicide treated plots. The application of different herbicide doses did not differentiate significantly the weed infestation level in the winter wheat canopy. Galium aparine, Papaver rhoeas, Viola arvensis and Apera spica-venti were dominant weed species in the winter wheat canopy. Foliar application of fertilizers did not influence the weed infestation level in the crop canopy. Molecular analysis showed that herbicide application did not affect genetic variation in the populations of Galium aparine and Apera spica-venti.

  2. Interferência das plantas daninhas na cultura do amendoim das águas: efeitos de espaçamentos, variedades e períodos de convivência Weed interference in peanut: effects of row spacing, cultivars and weeding period

    Directory of Open Access Journals (Sweden)

    Dagoberto Martins

    1994-01-01

    . Pennisetum setosum was the main weed in the experimental area. ln the 0.4 m spacing, 10 days were enough to reduce the dry weight of the weeds, whereas, on spacing of 0.6 m 30 days were necessary for weed control. The number of pods per plant was the main yield component affected by the weed community and, as a consequence, pod and grain yield per unit of area were affected. The weeding periods were not influenced by peanut spacing. Cultivar Tatu had to be maintained free of weed interference for 20 days and cultivar Tatuí for 10 days after peanut emergence to prevent yield loss.

  3. Interactions between pre- and post-emergence weed harrowing in spring cereals

    DEFF Research Database (Denmark)

    Brandsæter, L.O.; Mangerud, K.; Rasmussen, Jesper

    2012-01-01

    that pre- and post-emergence harrowing interact positively, that a combination gives more stable weed control effects than pre- and post-emergence weed harrowing used alone, and that a harrow type with bent tines is more aggressive and suitable on hard-packed soils than a harrow with strait tines...... the average effect of post-emergence harrowing was 47% on weed density and 41% on weed biomass. The combined effect of pre- and post-emergence weed harrowing was 61% on weed density and 54% on weed biomass. The combination did not give more stable weed control effects than pre- and post-emergence weed...... harrowing used alone. Pre-emergence harrowing increased the average crop yield by 6.2%, post-emergence harrowing by 4.0% and the combined effect was 10%. Crop yield was mainly increased on hard-packed soils. Weed and crop responses varied strongly among experiments, but the efficacy of pre- and post...

  4. Organic fields sustain weed metacommunity dynamics in farmland landscapes.

    Science.gov (United States)

    Henckel, Laura; Börger, Luca; Meiss, Helmut; Gaba, Sabrina; Bretagnolle, Vincent

    2015-06-07

    Agro-ecosystems constitute essential habitat for many organisms. Agricultural intensification, however, has caused a strong decline of farmland biodiversity. Organic farming (OF) is often presented as a more biodiversity-friendly practice, but the generality of the beneficial effects of OF is debated as the effects appear often species- and context-dependent, and current research has highlighted the need to quantify the relative effects of local- and landscape-scale management on farmland biodiversity. Yet very few studies have investigated the landscape-level effects of OF; that is to say, how the biodiversity of a field is affected by the presence or density of organically farmed fields in the surrounding landscape. We addressed this issue using the metacommunity framework, with weed species richness in winter wheat within an intensively farmed landscape in France as model system. Controlling for the effects of local and landscape structure, we showed that OF leads to higher local weed diversity and that the presence of OF in the landscape is associated with higher local weed biodiversity also for conventionally farmed fields, and may reach a similar biodiversity level to organic fields in field margins. Based on these results, we derive indications for improving the sustainable management of farming systems. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  5. Team-up Crop Diversification and Weed Management: PRODIVA

    DEFF Research Database (Denmark)

    Gerowitt, B.; Melander, B.; Krawczyk, R.

    2015-01-01

    The research-network PRODIVA focuses on a better utilization of crop diversification for weed management in North European arable cropping systems. The goal is to maintain diverse arable weed vegetation that is manageable in the long-term and could fulfil other necessary systemfunctions including...... support of beneficial organisms. The partners in PRODIVA will synthesize knowledge from terminated and running research projects and set-up selected new experiments on cover crops and variety resp. crop mixtures. Moreover, we will interact with partners from farming practice and extension services...... in organic agriculture. Regional fields will be surveyed for weeds to safeguard the relevance of the experimental research. Current cropping practices and their influence on weed pressure and weed diversity will be identified. The project will involve relevant stakeholders from the participating countries...

  6. Effects of allelopathic chemicals extracted from various plant leaves on weed control and wheat crop productivity

    International Nuclear Information System (INIS)

    Khan, E.A.; Khakwani, A.A.; Ghazanfarullah, A.

    2015-01-01

    A study on allelopathic effect of leaf water extracts of Eucalyptus, Acacia, Sorghum, Shishum, Sunflower, Poplar, Tobacco and Congress grass on weeds control and growth of wheat cv. Hashim-8 was conducted at Faculty of Agriculture, Gomal University, Dera Ismail Khan during 2012-2013. The findings of this study revealed that allelopathic chemicals in leaf water extracts of these plants significantly suppressed weeds growth by reducing weed density, fresh and dry weed biomass, and encouraged wheat yield and yield components such as days to 50% heading, plant height, tillers m-2, grain spike-1, 1000-gain weight, biological and grain yield. Even though minimum fresh and dry weed biomass and highest wheat grain yield and yield related components were observed in twice hand weeding treatment which is economically less feasible on large scale. However, our findings showed an alternative allelopathic technique to minimize weed infestation and boost wheat growth and yield using natural plant material. On the basis of present results, it is recommended that leaf water extracts of Sorghum, Sunflower and Congress grass can be applied twice (30 and 60 DAS) during the growing season to control weeds and to enhance wheat grain yield. (author)

  7. The changing role of agriculture and tomorrow's weed research agenda

    NARCIS (Netherlands)

    Kropff, M.J.; Bastiaans, L.; Kempenaar, C.; Weide, van der R.Y.

    2008-01-01

    With the changing position of agriculture in the world the challenges for weed management and weed science are changing as well. In this paper recent developments in weed science with respect to several aspects of weed management are discussed in relation to those changes. Developments in cultural

  8. Rounding Up the Astrophysical Weeds

    Science.gov (United States)

    McMillan, James P.

    2016-09-01

    New instruments used for astronomy such as ALMA, Herschel, and SOFIA have greatly increased the quality of available astrophysical data. These improved data contain spectral lines and features which are not accounted for in the quantum mechanical (QM) catalogs. A class of molecules has been identified as being particularly problematic, the so-called "weeds". These molecules have numerous transitions, of non-trivial intensity, which are difficult to model due to highly perturbed low lying vibrational states. The inability to properly describe the complete contribution of these weeds to the astrophysical data has led directly to the misidentification of other target molecules. Ohio State's Microwave Laboratory has developed an alternative approach to this problem. Rather than relying on complex QM calculations, we have developed a temperature dependent approach to laboratory based terahertz spectroscopy. We have developed a set of simple packages, in addition to traditional line list catalogs, that enable astronomers to successfully remove the weed signals from their data. This dissertation will detail my laboratory work and analysis of three keys weeds: methanol, methyl formate and methyl cyanide. Also, discussed will be the analytical technique I used to apply these laboratory results to astrophysical data.

  9. The Power and Potential of Genomics in Weed Biology and Management.

    Science.gov (United States)

    Ravet, Karl; Patterson, Eric L; Krähmer, Hansjörg; Hamouzová, Kateřina; Fan, Longjiang; Jasieniuk, Marie; Lawton-Rauh, Amy; Malone, Jenna M; Scott McElroy, J; Merotto, Aldo; Westra, Philip; Preston, Christopher; Vila-Aiub, Martin M; Busi, Roberto; Tranel, Patrick J; Reinhardt, Carl; Saski, Christopher; Beffa, Roland; Neve, Paul; Gaines, Todd A

    2018-04-24

    There have been previous calls for, and efforts focused on, realizing the power and potential of weed genomics for better understanding of weeds. Sustained advances in genome sequencing and assembly technologies now make it possible for individual research groups to generate reference genomes for multiple weed species at reasonable costs. Here, we present the outcomes from several meetings, discussions, and workshops focused on establishing an International Weed Genomics Consortium (IWGC) for a coordinated international effort in weed genomics. We review the 'state of the art' in genomics and weed genomics, including technologies, applications, and on-going weed genome projects. We also report the outcomes from a workshop and a global survey of the weed science community to identify priority species, key biological questions, and weed management applications that can be addressed through greater availability of, and access to, genomic resources. Major focus areas include the evolution of herbicide resistance and weedy traits, the development of molecular diagnostics, and the identification of novel targets and approaches for weed management. There is increasing interest in, and need for, weed genomics, and the establishment of the IWGC will provide the necessary global platform for communication and coordination of weed genomics research. This article is protected by copyright. All rights reserved.

  10. Interspecific variation in persistence of buried weed seeds follows trade-offs among physiological, chemical, and physical seed defenses.

    Science.gov (United States)

    Davis, Adam S; Fu, Xianhui; Schutte, Brian J; Berhow, Mark A; Dalling, James W

    2016-10-01

    Soil seedbanks drive infestations of annual weeds, yet weed management focuses largely on seedling mortality. As weed seedbanks increasingly become reservoirs of herbicide resistance, species-specific seedbank management approaches will be essential to weed control. However, the development of seedbank management strategies can only develop from an understanding of how seed traits affect persistence.We quantified interspecific trade-offs among physiological, chemical, and physical traits of weed seeds and their persistence in the soil seedbank in a common garden study. Seeds of 11 annual weed species were buried in Savoy, IL, from 2007 through 2012. Seedling recruitment was measured weekly and seed viability measured annually. Seed physiological (dormancy), chemical (phenolic compound diversity and concentration; invertebrate toxicity), and physical traits (seed coat mass, thickness, and rupture resistance) were measured.Seed half-life in the soil ( t 0.5 ) showed strong interspecific variation ( F 10,30  = 15, p  central role of seed dormancy in controlling seed persistence.A quantitative comparison between our results and other published work indicated that weed seed dormancy and seedbank persistence are linked across diverse environments and agroecosystems. Moreover, among seedbank-forming early successional plant species, relative investment in chemical and physical seed defense varies with seedbank persistence. Synthesis and applications . Strong covariance among weed seed traits and persistence in the soil seedbank indicates potential for seedbank management practices tailored to specific weed species. In particular, species with high t 0.5 values tend to invest less in chemical defenses. This makes them highly vulnerable to physical harvest weed seed control strategies, with small amounts of damage resulting in their full decay.

  11. Evaluation of yield quality and weed infestation of common valerian (Valeriana officinalis L. in dependence on weed control method and forecrop.

    Directory of Open Access Journals (Sweden)

    Cezary Kwiatkowski

    2012-12-01

    Full Text Available A field experiment involving the cultivation of common valerian was conducted on loess soil in Abramów (Lublin region in the period 2007-2009. Qualitative parameters of herbal raw material obtained from this plant as well as in-crop weed infestation were evaluated depending on the protection method and forecrop. Hand-weeded plots, in which a hand hoe was used, were the control. In the other treatments, weeds were controlled using various herbicides and a mechanical implement (brush weeder. Potato and winter wheat + field pea cover crop were the forecrops for common valerian crops. A hypothesis was made that the use of a brush weeder and herbicides not registered for application in valerian crops would have a positive effect on this plant's productivity and weed infestation in its crops. It was also assumed that the introduction of a cover crop would allow the elimination of differences in the forecrop value of the crop stands in question. The best quantitative and qualitative parameters of common valerian raw material as well as the largest reduction of incrop weed infestation were recorded after the application of the herbicides which were not type approved. The use of the brush weeder in the interrows also had a beneficial effect on productivity of the plant in question, but secondary weed infestation at the end of the growing season of common valerian turned out to be its disadvantage. Traditional crop protection methods used in common valerian crops were less effective in weed infestation reduction and they resulted in lower plant productivity and raw material quality. Potato proved to be a better forecrop for common valerian than winter wheat + field pea; however, this positive effect was not confirmed statistically. The following annual weeds: Chenopodium album, Galinsoga parviflora, Stellaria media, were predominant in the common valerian crop. Traditional weed control methods resulted in the dominance of some dicotyledonous weeds, such

  12. Weed identification using an automated active shape matching (AASM) technique

    DEFF Research Database (Denmark)

    C. Swain, Kishore; Nørremark, Michael; Jørgensen, Rasmus Nyholm

    2011-01-01

    Weed identification and control is a challenge for intercultural operations in agriculture. As an alternative to chemical pest control, a smart weed identification technique followed by mechanical weed control system could be developed. The proposed smart identification technique works on the con......Weed identification and control is a challenge for intercultural operations in agriculture. As an alternative to chemical pest control, a smart weed identification technique followed by mechanical weed control system could be developed. The proposed smart identification technique works...... on the concept of ‘active shape modelling’ to identify weed and crop plants based on their morphology. The automated active shape matching system (AASM) technique consisted of, i) a Pixelink camera ii) an LTI (Lehrstuhlfuer technische informatik) image processing library, iii) a laptop pc with the Linux OS. A 2...

  13. Precise tillage systems for enhanced non-chemical weed management

    NARCIS (Netherlands)

    Kurstjens, D.A.G.

    2007-01-01

    Soil and residue manipulation can assist weed management by killing weeds mechanically, interfering in weed lifecycles, facilitating operations and enhancing crop establishment and growth. Current tillage systems often compromise these functions, resulting in heavy reliance on herbicides,

  14. Seeding method and rate influence on weed suppression in aerobic ...

    African Journals Online (AJOL)

    High weed pressure is amongst the major constraints to the extensive adoption of aerobic rice system as a water-wise technique. Towards developing a sustainable weed management strategy, seeding method and rate may substantially contribute to weed suppression and reduce herbicide use and weeding cost. A trough ...

  15. Wallowa Canyonlands Weed Partnership : Completion Report November 19, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Mark C.; Ketchum, Sarah

    2008-12-30

    Noxious weeds threaten fish and wildlife habitat by contributing to increased sedimentation rates, diminishing riparian structure and function, and reducing forage quality and quantity. Wallowa Resources Wallowa Canyonlands Partnership (WCP) protects the unique ecological and economic values of the Hells Canyon grasslands along lower Joseph Creek, the lower Grande Ronde and Imnaha Rivers from invasion and degradation by noxious weeds using Integrated Weed Management techniques. Objectives of this grant were to inventory and map high priority weeds, coordinate treatment of those weeds, release and monitor bio-control agents, educate the public as to the dangers of noxious weeds and how to deal with them, and restore lands to productive plant communities after treatment. With collaborative help from partners, WCP inventoried {approx} 215,000 upland acres and 52.2 miles of riparian habitat, released bio-controls at 23 sites, and educated the public through posters, weed profiles, newspaper articles, and radio advertisements. Additionally, WCP used other sources of funding to finance the treatment of 1,802 acres during the course of this grant.

  16. Phosphoric acid pretreatment of Achyranthes aspera and Sida acuta weed biomass to improve enzymatic hydrolysis.

    Science.gov (United States)

    Siripong, Premjet; Duangporn, Premjet; Takata, Eri; Tsutsumi, Yuji

    2016-03-01

    Achyranthes aspera and Sida acuta, two types of weed biomass are abundant and waste in Thailand. We focus on them as novel feedstock for bio-ethanol production because they contain high-cellulose content (45.9% and 46.9%, respectively) and unutilized material. Phosphoric acid (70%, 75%, and 80%) was employed for the pretreatment to improve by enzymatic hydrolysis. The pretreatment process removed most of the xylan and a part of the lignin from the weeds, while most of the glucan remained. The cellulose conversion to glucose was greater for pretreated A. aspera (86.2 ± 0.3%) than that of the pretreated S. acuta (82.2 ± 1.1%). Thus, the removal of hemicellulose significantly affected the efficiency of the enzymatic hydrolysis. The scanning electron microscopy images showed the exposed fibrous cellulose on the cell wall surface, and this substantial change of the surface structure contributed to improving the enzyme accessibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. BIOLOGICAL CONTROL OF WEEDS BY MEANS OF PLANT PATHOGENS

    Directory of Open Access Journals (Sweden)

    Marija Ravlić

    2014-06-01

    Full Text Available Biological control is the use of live beneficial organisms and products of their metabolism in the pests control. Plant pathogens can be used for weed control in three different ways: as classical, conservation and augmentative (inoculative and inundated biological control. Inundated biological control involves the use of bioherbicides (mycoherbicides or artificial breeding of pathogens and application in specific stages of crops and weeds. Biological control of weeds can be used where chemical herbicides are not allowed, if resistant weed species are present or in the integrated pest management against weeds with reduced herbicides doses and other non-chemical measures, but it has certain limitations and disadvantages.

  18. Cover crop-based ecological weed management: exploration and optimization

    NARCIS (Netherlands)

    Kruidhof, H.M.

    2008-01-01

    Keywords: organic farming, ecologically-based weed management, cover crops, green manure, allelopathy, Secale cereale, Brassica napus, Medicago sativa

    Cover crop-based ecological weed management: exploration and optimization. In organic farming systems, weed control is recognized as one

  19. Evaluation of multi-species weed competition and weeds population dynamic in corn Zea mays L. field

    Directory of Open Access Journals (Sweden)

    S Mijani

    2016-05-01

    Full Text Available In order to examine the multi-species weed competition in corn field an experiment as an interval mapping was carried out at the Agricultural Research field of Ferdowsi University of Mashhad during growing season 2009-2010. At 3-4 leafy stages of corn, 20 non-destructive quadrates determine and the density of weeds was counted separately. At the same time, 20 destructive quadrates determine and in addition of counting number of plants, leaf area index and dry weight of each species were recorded separately. By using data from previous section, hyperbolic functions were fitted. In these functions number of species serve as the independent variable, weight or leaf area was considered as the dependent variable. With the help of these functions and leaf dry weight of each species was determined for non-destructive quadrates at this stage. Relative leaf area at early season as independent variables and natural logarithm of individual plant weight at later season as dependent variable in a multiple linear regression was fitted to obtain the interspecies competition coefficients. Based on ln of weight of single plant equation the weed interference effects on the corn yield can be divided into two groups: inhibition (negative sign and stimulation (positive sign. Among all weeds, night shade (Solanum nigrum L., redroot pigweed (Amaranthus retroflexus L. and lambsquarter (Chenopodium album L. had positive effects on corn yield, respectively. In fact, these weeds had competition and negative impacts on other weeds and reduced their competition power with corn and caused facilitation role on corn yield. At the end of growing season of corn, population of lambsquarter and Common purslane (Portulaca oleracea L. decreased while population of barnyard grass(Echinochloa crus-galli L., redroot pigweed and night shade increased.

  20. Impact of an invasive weed, Parthenium hysterophorus, on a pasture community in south east Queensland, Australia.

    Science.gov (United States)

    Nguyen, Thi; Bajwa, Ali Ahsan; Belgeri, Amalia; Navie, Sheldon; O'Donnell, Chris; Adkins, Steve

    2017-12-01

    Parthenium weed is a highly invasive alien species in more than 40 countries around the world. Along with severe negative effects on human and animal health and crop production, it also causes harm to ecosystem functioning by reducing the native plant species biodiversity. However, its impacts on native plant species, especially in pasture communities, are less known. Given parthenium weed causes substantial losses to Australian pastures' productivity, it is crucial to estimate its impact on pasture communities. This study evaluates the impact of parthenium weed upon species diversity in a pasture community at Kilcoy, south east Queensland, Australia. Sub-sites containing three levels of parthenium weed density (i.e. high, low and zero) were chosen to quantify the above- and below-ground plant community structure. Species richness, diversity and evenness were all found to be significantly reduced as the density of parthenium weed increased; an effect was evident even when parthenium weed was present at relatively low densities (i.e. two plants m -2 ). This trend was observed in the summer season as well as in winter season when this annual weed was absent from the above-ground plant community. This demonstrates the strong impact that parthenium weed has upon the community composition and functioning throughout the year. It also shows the long-term impact of parthenium weed on the soil seed bank where it had displaced several native species. So, management options used for parthenium weed should also consider the reduction of parthenium weed seed bank along with controlling its above-ground populations.

  1. Estimating economic thresholds for site-specific weed control using manual weed counts and sensor technology: an example based on three winter wheat trials.

    Science.gov (United States)

    Keller, Martina; Gutjahr, Christoph; Möhring, Jens; Weis, Martin; Sökefeld, Markus; Gerhards, Roland

    2014-02-01

    Precision experimental design uses the natural heterogeneity of agricultural fields and combines sensor technology with linear mixed models to estimate the effect of weeds, soil properties and herbicide on yield. These estimates can be used to derive economic thresholds. Three field trials are presented using the precision experimental design in winter wheat. Weed densities were determined by manual sampling and bi-spectral cameras, yield and soil properties were mapped. Galium aparine, other broad-leaved weeds and Alopecurus myosuroides reduced yield by 17.5, 1.2 and 12.4 kg ha(-1) plant(-1)  m(2) in one trial. The determined thresholds for site-specific weed control with independently applied herbicides were 4, 48 and 12 plants m(-2), respectively. Spring drought reduced yield effects of weeds considerably in one trial, since water became yield limiting. A negative herbicide effect on the crop was negligible, except in one trial, in which the herbicide mixture tended to reduce yield by 0.6 t ha(-1). Bi-spectral cameras for weed counting were of limited use and still need improvement. Nevertheless, large weed patches were correctly identified. The current paper presents a new approach to conducting field trials and deriving decision rules for weed control in farmers' fields. © 2013 Society of Chemical Industry.

  2. Influence of cowpea and melon populations on weed infestation and ...

    African Journals Online (AJOL)

    Small farmers in the humid regions of tropical Africa spend 30–42% of their total farm labour input in controlling weeds. Chemical weed control is normally recommended but high cost of herbicides and environmental pollution are specific problems with chemical weed control. A three year bio-weed control system with three ...

  3. Effects of weed cover composition on insect pest and natural enemy abundance in a field of Dracaena marginata (Asparagales: Asparagaceae) in Costa Rica.

    Science.gov (United States)

    Sadof, Clifford S; Linkimer, Mildred; Hidalgo, Eduardo; Casanoves, Fernando; Gibson, Kevin; Benjamin, Tamara J

    2014-04-01

    Weeds and their influence on pest and natural enemy populations were studied on a commercial ornamental farm during 2009 in the Atlantic Zone of Costa Rica. A baseline survey of the entire production plot was conducted in February, along a 5 by 5 m grid to characterize and map initial weed communities of plants, cicadellids, katydids, and armored scales. In total, 50 plant species from 21 families were found. Seven weed treatments were established to determine how weed manipulations would affect communities of our targeted pests and natural enemies. These treatments were selected based on reported effects of specific weed cover on herbivorous insects and natural enemies, or by their use by growers as a cover crop. Treatments ranged from weed-free to being completely covered with endemic species of weeds. Although some weed treatments changed pest abundances, responses differed among arthropod pests, with the strongest effects observed for Caldwelliola and Empoasca leafhoppers. Removal of all weeds increased the abundance of Empoasca, whereas leaving mostly cyperacaeous weeds increased the abundance of Caldwelliola. Weed manipulations had no effect on the abundance of katydid and scale populations. No weed treatment reduced the abundance of all three of the target pests. Differential responses of the two leafhopper species to the same weed treatments support hypotheses, suggesting that noncrop plants can alter the abundance of pests through their effects on arthropod host finding and acceptance, as well as their impacts on natural enemies.

  4. Focus on ecological weed management : what is hindering adoption?

    NARCIS (Netherlands)

    Bastiaans, L.; Paolini, R.; Baumann, D.T.

    2008-01-01

    Despite increased concerns regarding the heavy reliance of many cropping systems on chemical weed control, adoption of ecological weed management practices is only steadily progressing. For this reason, this paper reflects on both the possibilities and limitations of cultural weed control practices.

  5. Evaluating Rimsulforon Efficiency on Controlling Weeds in Potato at Different Growth Stages

    Directory of Open Access Journals (Sweden)

    A. Khatami

    2017-08-01

    were analyzed using SAS 9.1 and MSTAT-C. Analysis of variance was used to test the significance of variance sources, and Duncan’s Multiple range test (P ≤ 0.05 was used to compare the differences among treatments. Results and Discussion Results showed that the maximum reduction percent of redroot pigweed (Amaranthus retroflexus L., field bind weed (Convolvulus arvensis L., lambsquarter (Chenopodium album L., total weed biomass and density achieved by 40 and 50 gr a.i. / ha application. So that 40 and 50 gr a.i. /ha of rimsulfuron compared to control reduced weed density up to 49.47and 55.38 % and biomass up to 89.97 and 94.63 %, respectively. Also results showed that 40 and 50 gr a.i. /ha of rimsulfuron compared to control reduced biomass of redroot pigweed 89.91 and 95.50 %, Field bind weed 84.28 and 94.79 % and lambsquarter 92.75 and 96.87 percent respectively. That there was not statistically significant difference between 40 and 50 gr a.i. /ha of rimsulfuron. Among rimsulfuron application times, potato emergence stage reduced total weed density and biomass 36.45 and 68.04 %, respectively which is compared to control (weedy. Rimsulfuron application at potato emergence stage reduced biomass of redroot pigweed and lambsquarter 62.51 and 71.08 percent respectively. However it had no significant effect on biomass of Field bind weed. The results showed that potato tuber yield was 46.31 and 45.96 ton/ ha while rimsulfuron applied 40 and 50 gr a.i. / ha. Among rimsulfuron application times, potato emergence stage had total tuber yield 47.58 ton/ha. Conclusion Results showed that the maximum reduction percentage in weed density and biomass was observed for treatments in which were used 40 and 50 gr a.i. / ha application. Application of rimsulfuron at potato emergence reduced weed density and biomass and increased total tuber yield. Itproves the effectiveness of the rimsulfuron for potato emergence without damage. Furthermore the effective dose of rimsulfuron for 50

  6. Biological Efficacy of Herbicides for Weed Control in Noncropped Areas

    Directory of Open Access Journals (Sweden)

    Tsvetanka Dimitrova

    2009-01-01

    Full Text Available An increasing problem facing agricultural producers is the invasion of weeds, perennial in particular, so that implementation of industrial technologies is impossible without their highly efficient and rational control. For the purpose of studying efficient herbicides for weed control in noncropped areas (stubbles, a biological study of five total systemic herbicides was conducted in areas under natural weed infestation and pressure from othersurrounding weeds at the Institute of Forage Crops in Pleven in 2005-2007. The trials were carried out in field conditions using the block method with plot size of 20 m². Treatment was conducted at the predominant stage of budding of perennial dicotyledonous weeds and earing of monocotyledonous weeds. Herbicidal efficacy was recorded on the EWRS 9-score scale (0-100% killed weeds = score 9-1. It was found that treatment of noncropped areas (stubbles with the total systemic herbicides Touchdown System 4 (360 g/l glyphosate; Cosmic (360 g/l glyphosate; Roundup Plus (441 g/l glyphosate potassium salt; Leon 36 SL (360 g/l glyphosate and Glyphos Super 45 SL (450 g/l glyphosate was highly efficient, so that it was a successful element of a strategy for controlling weeds of different biological groups, and was especially effective against perennial weeds.

  7. Effect of different input management on weed composition, diversity and density of corn field

    Directory of Open Access Journals (Sweden)

    Surur Khoramdel

    2016-04-01

    Full Text Available In order to investigate the effects of input intensity on species diversity, composition and density of weeds in corn (Zea mays L., an experiment was conducted based on a randomized complete block design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad, Iran during the year 2009. Treatments included low input, medium input and high input systems. Low input received 30 tonha-1or 30 tonha-1 compost, zero tillage and hand weeding (twice. Medium input was based on 15 tonha-1 manure, 150 kgha-1 urea as chemical fertilizer, twice tillage operations and 2, 4-D (1.5 Lha-1, at five leaves emergence as an herbicide and hand weeding (once. High input received 300 kgha-1 urea, four tillage operations and Paraquat (2 Lha-1, after planting and 2, 4-D (1.5 Lha-1, at five leaves emergence. Manure and compost were applied in the planting time. Weed samplings were done in three stages (early, mid and late growing season. Results indicated that the highest and the lowest weed species diversity and density were observed in low input based on manure and high input systems, respectively. The highest range of weed relative density was obtained for black nightshade (Solanum nigrum with 9.09-75.00%. The highest number of species was observed in low input based on manure. Also, management practices affected weed dry matter and diversity indices. The highest and the lowest amounts of weed dry matter were observed in low input based on manure and high input systems, respectively. In the first, second and the third stages of sampling, the maximum and the minimum amounts of Margalef index were observed in low input based on manure (with 5.3, 5.4 and 3.3, respectively and high input systems (with 0.8, 2.3 and 2.6, respectively. In the first, second and the third stages of sampling, the highest and the lowest values of Shannon index were observed in low input based on manure (with 0.6, 0.7 and 0.5 respectively and high input (with 0

  8. RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean

    NARCIS (Netherlands)

    Horvath, David P; Hansen, Stephanie A; Moriles-Miller, Janet P; Pierik, Ronald; Yan, Changhui; Clay, David E; Scheffler, Brian; Clay, Sharon A

    Weeds reduce yield in soybeans (Glycine max) through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. RNASeq data were collected from six biological samples of soybeans growing with or without

  9. Evaluation of mulching materials as integrated weed management component in maize crop

    International Nuclear Information System (INIS)

    Shah, F.U.

    2014-01-01

    Yield losses by weeds in maize crop and demonstrated efficacy of various mulches in weed management led to check the efficacy of various available mulches for suppressing weeds in maize crop at National Agricultural Research Centre (NARC), Islamabad during kharif (autumn) season 2011. The experiment was laid in Randomized Complete Block Design, (RBCD) having eight treatments and four replications. The treatments were black plastic, white plastic, sugarcane straw, wheat straw, live mulch, weeds as mulch, hand weeding and weedy check. Weed data included weed density m, fresh and dry weight g m, while crop data included crop density m, fresh and dry weight g m, number of plant plot, stover yield (g), plant height (cm), number of cobs plant, number of leaves plant, average grain number of five cobs and grain yield (t ha). With the exception of hand weeding, minimum number of weeds 128 m and 164 m were recorded in black plastic and weeds as mulch, respectively, compared to 595 min weedy check. Similarly, maximum grain yields (1.91 and 1.85 tha) were recorded in black plastic and weeds as mulch, while minimum grain yield (0.64 t ha) was recorded in weedy check plots. The economic net returns of black plastic mulch and weeds as mulch were Rs. 39,824 and Rs. 38,291, respectively as compared to Rs. 21431 for weedy check. Yield increased by 21.1 and 16.5% over hand weeding by plastic mulch and weeds as mulch, respectively. Black plastic followed by weeds as mulch, are recommended to control weeds and get maximum yield as well as net economic return. (author)

  10. Ozone exposure of a weed community produces adaptive changes in seed populations of Spergula arvensis.

    Directory of Open Access Journals (Sweden)

    Jennifer B Landesmann

    Full Text Available Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb. We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production.

  11. Ozone exposure of a weed community produces adaptive changes in seed populations of Spergula arvensis.

    Science.gov (United States)

    Landesmann, Jennifer B; Gundel, Pedro E; Martínez-Ghersa, M Alejandra; Ghersa, Claudio M

    2013-01-01

    Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production.

  12. Fusion of pixel and object-based features for weed mapping using unmanned aerial vehicle imagery

    Science.gov (United States)

    Gao, Junfeng; Liao, Wenzhi; Nuyttens, David; Lootens, Peter; Vangeyte, Jürgen; Pižurica, Aleksandra; He, Yong; Pieters, Jan G.

    2018-05-01

    The developments in the use of unmanned aerial vehicles (UAVs) and advanced imaging sensors provide new opportunities for ultra-high resolution (e.g., less than a 10 cm ground sampling distance (GSD)) crop field monitoring and mapping in precision agriculture applications. In this study, we developed a strategy for inter- and intra-row weed detection in early season maize fields from aerial visual imagery. More specifically, the Hough transform algorithm (HT) was applied to the orthomosaicked images for inter-row weed detection. A semi-automatic Object-Based Image Analysis (OBIA) procedure was developed with Random Forests (RF) combined with feature selection techniques to classify soil, weeds and maize. Furthermore, the two binary weed masks generated from HT and OBIA were fused for accurate binary weed image. The developed RF classifier was evaluated by 5-fold cross validation, and it obtained an overall accuracy of 0.945, and Kappa value of 0.912. Finally, the relationship of detected weeds and their ground truth densities was quantified by a fitted linear model with a coefficient of determination of 0.895 and a root mean square error of 0.026. Besides, the importance of input features was evaluated, and it was found that the ratio of vegetation length and width was the most significant feature for the classification model. Overall, our approach can yield a satisfactory weed map, and we expect that the obtained accurate and timely weed map from UAV imagery will be applicable to realize site-specific weed management (SSWM) in early season crop fields for reducing spraying non-selective herbicides and costs.

  13. Management of fresh water weeds (macrophytes) by vermicomposting using Eisenia fetida.

    Science.gov (United States)

    Najar, Ishtiyaq Ahmed; Khan, Anisa B

    2013-09-01

    In the present study, potential of Eisenia fetida to recycle the different types of fresh water weeds (macrophytes) used as substrate in different reactors (Azolla pinnata reactor, Trapa natans reactor, Ceratophyllum demersum reactor, free-floating macrophytes mixture reactor, and submerged macrophytes mixture reactor) during 2 months experiment is investigated. E. fetida showed significant variation in number and weight among the reactors and during the different fortnights (P macrophytes mixture reactor (number 105 ± 5.77 %; weight 41.07 ± 3.97 % ). ANOVA showed significant variation in cocoon production (F4 = 15.67, P macrophyte affects the growth and reproduction pattern of E. fetida among the different reactors, further the addition of A. pinnata in other macrophytes reactors can improve their recycling by E. fetida.

  14. Effect of sunn hemp (Crotalaria juncea L.) cutting date and planting density on weed suppression in Georgia, USA.

    Science.gov (United States)

    Morris, J Bradley; Chase, Carlene; Treadwell, Danielle; Koenig, Rosie; Cho, Alyssa; Morales-Payan, Jose Pable; Murphy, Tim; Antonious, George F

    2015-01-01

    A field study was conducted in 2008 and 2009 at the USDA, ARS, Plant Genetic Resources Conservation Unit in Griffin, GA, to investigate weed suppression by sunn hemp (Crotalaria juncea L). The objectives were to (1) evaluate the effects of apical meristem removal (AMR) at three dates [5, 6, and 7 wks after planting (WAP) on May 14, 2008 and May 21, 2009] and (2) assess the impact of seeding rates (11, 28, and 45 kg ha(-1)) on weed biomass reduction. Weed species were identified at 4, 8, and 12 wks after sunn hemp planting. Sunn hemp cutting date had no significant effect on weed suppression in 2008 but significant differences for grass weeds at 4, 8, and 12 WAP and for yellow nutsedge at 8 and 12 WAP did occur when compared to the control in 2009. In comparison to the sunn hemp-free control plot in 2009, all three seeding rates had reduced grass weed dry weights at 4, 8, and 12 WAP. The total mass of yellow nutsedge when grown with sunn hemp was reduced compared to the total mass of yellow nutsedge grown in the weedy check for all seeding rates at 8 and 12 WAP. Lower grass weed biomass was observed by 12 WAP for cutting dates and seeding rates during 2008 and 2009. Sunn hemp cutting date and seeding rate reduced branch numbers in both years. The reduction in sunn hemp seeding rates revealed a decrease in weed populations.

  15. Assessment of weeds as alternative hosts of plant-parasitic nematodes in coffee plantations in Costa Rica

    Directory of Open Access Journals (Sweden)

    Walter Peraza-Padilla

    2018-01-01

    Full Text Available There is potential for weeds to be alternative hosts of plant-parasitic nematodes (PPN, but a methodology that assesses the phytosanitary risk derived from the presence of weeds in plantations is not available. This research was conducted in order to determine if the presence of weeds in coffee plantations (organic and conventional represented a phytosanitary risk due to their role as alternative hosts of PPN. The research was developed into two plantation located in Aserrí, San José, Costa Rica during August, 2010. The most important weeds were identified in the plantations, also nematodes of the genera Meloidogyne, Pratylenchus and Helicotylenchus were quantified in soil and roots from selected weeds and coffee plants. A permutational analysis of variance was executed in order to determine the genera of PPN that significantly differed from the ones found in weeds to the ones found in coffee plants. Based on these results, the weeds were classified as: reservoir, trap crop, or weak host of PPN. This classification criterion, in addition to life cycle and type of parasitism of the PPN were used to assign numerical values to the weeds. The values were used to calculate the Phytosanitary Risk Index (PRI that acquired a maximum value of 10 for the weed Piper umbellatum in the organic plantation, and a maximum value of 24 for Commelina diffusa, Emilia fosbergii, Spananthe paniculata, Delilia biflora, and Spermacoce hirta in the conventional plantation. The results indicated that from a nematological perspective the presence of these weeds in coffee plantation could be a potential risk for coffee plants

  16. Weed suppression ability of spring barley varieties

    DEFF Research Database (Denmark)

    Christensen, Svend

    1995-01-01

    , Grit. Ranking varietal responses to weed competition in terms of grain yield loss corresponded well to ranking weed dry matter produced in crop weed mixtures. There was no correspondence between the varietal grain yields in pure stands and their competitiveness, suggesting that breeding to optimize...... both yielding and competitive ability may be possible. Non-linear regression models were fitted to canopy height and light interception data for each variety in all three years. The canopy height model provided a precise description of development and maximum canopy height of the varieties. A light...

  17. Weed Mapping with Co-Kriging Using Soil Properties

    DEFF Research Database (Denmark)

    Heisel, Torben; Ersbøll, Annette Kjær; Andreasen, Christian

    1999-01-01

    Our aim is to build reliable weed maps to control weeds in patches. Weed sampling is time consuming but there are some shortcuts. If an intensively sampled variable (e.g. soil property) can be used to improve estimation of a sparsely sampled variable (e.g. weed distribution), one can reduce weed...... sampling. The geostatistical estimation method co-kriging uses two or more sampled variables, which are correlated, to improve the estimation of one of the variables at locations where it was not sampled. We did an experiment on a 2.1 ha winter wheat field to compare co-kriging using soil properties......, with kriging based only on one variable. The results showed that co-kriging Lamium spp. from 96 0.25m2 sample plots ha-1 with silt content improved the prediction variance by 11% compared to kriging. With 51 or 18 sample plots ha-1 the prediction variance was improved by 21 and 15%....

  18. Dynamics of weed populations : spatial pattern formation and implications for control

    NARCIS (Netherlands)

    Wallinga, J.

    1998-01-01

    Modelling studies were carried out to analyse spatio-temporal dynamics of annual weed populations and to identify the key factors that determine the long-term herbicide use of weed control programmes. Three different weed control programmes were studied.

    In the first weed

  19. The weed seed bank assessment in two soil depths under various mineral fertilising

    Directory of Open Access Journals (Sweden)

    Elena Hunková

    2011-01-01

    Full Text Available The field trial at the experimental station of Slovak Agricultural University in Nitra - Kolíňany (Slovak Republic, maize growing region, Haplic Luvisol and Stagni-Haplic Luvisol in 1997 year was established. Experiments were based on 14 ha area (424 x 432.2 m by long strips method. The impact of different mineral fertilisers on six model crops was observed: winter wheat, spring barley, sunflower, winter oilseed rape, maize and sugar beet. Weed infestation of winter wheat, spring barley, maize and sugar beet as well as weed seed bank composition since 2000 year till 2002 year were detected. Three variants of mineral fertilisation were applied: variant 1 – without fertilisers, variant 2 – N-P-K fertilisation, steady state soil nutrients balance, variant 3 – high doses of N-P-K fertilisers (positive soil nutrients balance. Soil weed seed bank was analysed once per year before crop germination (on February from depths 0–0.05 m and 0.20–0.25 m in five replicates. From the depth 0–0.05 m 26 weed species were found, from the depth 0.20–0.25 m 23 weed species, from late spring group mainly. Chenopodium album, Stellaria media and Amaranthus spp. (77.57 % from intact seeds in total were the most occurred weeds in both depths. The year, depth of soil sampling and fertilisation did not have statistically significant impact on weed seeds number in the soil.

  20. Weed-crop competition effects on growth and yield of sugarcane planted using two methods

    International Nuclear Information System (INIS)

    Zafar, M.; Tanveer, A.; Cheema, Z.A.; Ashraf, M.

    2010-01-01

    Effect of planting techniques and weed-crop competition periods on yield potential of spring planted sugarcane variety HSF-240 was studied at the Ayub Agricultural Research Institute, Faisalabad, Pakistan. The experiment was laid out in RCBD with a split-plot arrangement, with four replications and net plot size of 3.6m x 10m. In the experiment, two planting techniques viz., 60 cm apart rows in flat sowing technique and 120 cm apart rows in trench sowing technique were randomized in main plots. Seven weed-crop competition periods viz., Zero (weed free), weed-crop competition for 45, 60, 75, 90, 105 days after sowing (DAS) and weedy check (full season weed-crop competition) were randomized in sub-plots. Sugarcane sown by trench method exhibited more leaf area index (LAI), average crop growth rate (ACGR) and yield contributing attributes. Trench sowing by yielding 72.22 and 75.08 t ha/sup -1/ stripped cane yields, significantly showed superiority over the flat sowing, which gave 64.13 and 66.04 t ha/sup -1/ stripped cane yields in 2005-06 and 2006- 07, respectively. Generally, there was an increase in weed population and biomass but decrease in leaf area index, crop growth rate and yield components with an increase in weed-crop competition period. A decrease of 10.06, 17.90, 22.42, 28.65, 37.64 and 56.89% in stripped cane yield was observed for weed-crop competition periods of 45, 60, 75, 90, 105 DAS and weedy check as compared with zero competition in 2005-06, respectively. In 2006-07, the respective decrease in stripped cane yield was 9.84, 18.76, 22.92, 27.98, 38.75, and 54.98%. Trench sowing at 1.2 m row spacing proved better sowing technique and 45 DAS was the critical period of weed-crop competition. (author)

  1. High-residue cultivation timing impact on organic no-till soybean weed management

    Science.gov (United States)

    A cereal rye cover crop mulch can suppress summer annual weeds early in the soybean growing season. However, a multi-tactic weed management approach is required when annual weed seedbanks are large or perennial weeds are present. In such situations, the weed suppression from a cereal rye mulch can b...

  2. SPATIAL CORRELATION BETWEEN PHYSICAL PROPERTIES OF SOIL AND WEEDS IN TWO MANAGEMENT SYSTEMS

    Directory of Open Access Journals (Sweden)

    Valter Roberto Schaffrath

    2015-02-01

    Full Text Available The spatial correlation between soil properties and weeds is relevant in agronomic and environmental terms. The analysis of this correlation is crucial for the interpretation of its meaning, for influencing factors such as dispersal mechanisms, seed production and survival, and the range of influence of soil management techniques. This study aimed to evaluate the spatial correlation between the physical properties of soil and weeds in no-tillage (NT and conventional tillage (CT systems. The following physical properties of soil and weeds were analyzed: soil bulk density, macroporosity, microporosity, total porosity, aeration capacity of soil matrix, soil water content at field capacity, weed shoot biomass, weed density, Commelina benghalensis density, and Bidens pilosa density. Generally, the ranges of the spatial correlations were higher in NT than in CT. The cross-variograms showed that many variables have a structure of combined spatial variation and can therefore be mapped from one another by co-kriging. This combined variation also allows inferences about the physical and biological meanings of the study variables. Results also showed that soil management systems influence the spatial dependence structure significantly.

  3. Weed Growth Stage Estimator Using Deep Convolutional Neural Networks

    DEFF Research Database (Denmark)

    Teimouri, Nima; Dyrmann, Mads; Nielsen, Per Rydahl

    2018-01-01

    This study outlines a new method of automatically estimating weed species and growth stages (from cotyledon until eight leaves are visible) of in situ images covering 18 weed species or families. Images of weeds growing within a variety of crops were gathered across variable environmental conditi...... in estimating the number of leaves and 96% accuracy when accepting a deviation of two leaves. These results show that this new method of using deep convolutional neural networks has a relatively high ability to estimate early growth stages across a wide variety of weed species....

  4. Chemical weed control in barley (hordeum vulgare)

    International Nuclear Information System (INIS)

    Sarwar, M.; Hassan, S.W.; Abid, A.A.

    2008-01-01

    Effect of two different pre-emergence herbicides i.e. Terbutryn (lgron-500FW) A, 1.01.25 kg a.t. ha/sup -1/ and Flurochloridone (Racer-25 CS) a 0.31, 0.37, 0.44, 0.50 and 0.56 Kg a.i. ha/sup -1/ on weeds and yield of barley wad studied under field conditions hb/sup -1/. All the herbicides significantly reduce the dry weight of weed Maximum reduction (70%) was observed in terbutryn a 1.0 Kg a.i. ha/sup -1/ Growth and yield parameters like number of spike lets per spike. Number of grams per spike. 1000-grain weight. Biological yield. Grain yield straw yield and harvest index showed significant response to various herbicides doses under study. Application of Flurochloridone (Racer-25 (CS) a 0.44 kg a.i. ha/sup -1/ and Terbutryn (lgran-500 FW) a 1.0 kg a.i). The data further revealed that in general all herbicide application treatments exhibited superior performance in respect of growth and yield over control. (author)

  5. A NOVEL WRAPPING CURVELET TRANSFORMATION BASED ANGULAR TEXTURE PATTERN (WCTATP EXTRACTION METHOD FOR WEED IDENTIFICATION

    Directory of Open Access Journals (Sweden)

    D. Ashok Kumar

    2016-02-01

    Full Text Available Apparently weed is a major menace in crop production as it competes with crop for nutrients, moisture, space and light which resulting in poor growth and development of the crop and finally yield. Yield loss accounts for even more than 70% when crops are frown under unweeded condition with severe weed infestation. Weed management is the most significant process in the agricultural applications to improve the crop productivity rate and reduce the herbicide application cost. Existing weed detection techniques does not yield better performance due to the complex background, illumination variation and crop and weed overlapping in the agricultural field image. Hence, there arises a need for the development of effective weed identification technique. To overcome this drawback, this paper proposes a novel Wrapping Curvelet Transformation Based Angular Texture Pattern Extraction Method (WCTATP for weed identification. In our proposed work, Global Histogram Equalization (GHE is used improve the quality of the image and Adaptive Median Filter (AMF is used for filtering the impulse noise from the image. Plant image identification is performed using green pixel extraction and k-means clustering. Wrapping Curvelet transform is applied to the plant image. Feature extraction is performed to extract the angular texture pattern of the plant image. Particle Swarm Optimization (PSO based Differential Evolution Feature Selection (DEFS approach is applied to select the optimal features. Then, the selected features are learned and passed through an RVM based classifier to find out the weed. Edge detection and contouring is performed to identify the weed in the plant image. The Fuzzy rule-based approach is applied to detect the low, medium and high levels of the weed patchiness. From the experimental results, it is clearly observed that the accuracy of the proposed approach is higher than the existing Support Vector Machine (SVM based approaches. The proposed approach

  6. Herbicide-resistant crops: utilities and limitations for herbicide-resistant weed management.

    Science.gov (United States)

    Green, Jerry M; Owen, Micheal D K

    2011-06-08

    Since 1996, genetically modified herbicide-resistant (HR) crops, particularly glyphosate-resistant (GR) crops, have transformed the tactics that corn, soybean, and cotton growers use to manage weeds. The use of GR crops continues to grow, but weeds are adapting to the common practice of using only glyphosate to control weeds. Growers using only a single mode of action to manage weeds need to change to a more diverse array of herbicidal, mechanical, and cultural practices to maintain the effectiveness of glyphosate. Unfortunately, the introduction of GR crops and the high initial efficacy of glyphosate often lead to a decline in the use of other herbicide options and less investment by industry to discover new herbicide active ingredients. With some exceptions, most growers can still manage their weed problems with currently available selective and HR crop-enabled herbicides. However, current crop management systems are in jeopardy given the pace at which weed populations are evolving glyphosate resistance. New HR crop technologies will expand the utility of currently available herbicides and enable new interim solutions for growers to manage HR weeds, but will not replace the long-term need to diversify weed management tactics and discover herbicides with new modes of action. This paper reviews the strengths and weaknesses of anticipated weed management options and the best management practices that growers need to implement in HR crops to maximize the long-term benefits of current technologies and reduce weed shifts to difficult-to-control and HR weeds.

  7. Seawater: an alternative grassy weed control method for post emergence herbicides in tropical turfgrass

    International Nuclear Information System (INIS)

    Uddin, M.K.; Ismail, M.R.; Juraimi, A.S.; Hamdani, S.A.

    2014-01-01

    Research was designed to reduce herbicide use by replacing post emergence herbicides with readily available sea water to control tropical turfgrass weeds. In studies evaluating the use of saline solutions for weed control, four salinity levels (0, 24, 48 and 72 dS m/sup -1/) were applied once to 30 grassy weed species, along with seashore paspalum (Paspalum vaginatum Swartz) (as a control) during December, 2007 to March, 2008. The results on injury ratings for salt tolerant weeds were categorized as highly susceptible, moderately susceptible and extremely tolerant. C. dactylon, E. indica, E. virescense, E. unioloides and I. globosa were very susceptible and found to be effectively controlled (100%) at 72 dS m/sup -1/ salinity treatment. However, two most serious weeds viz. wiry eragrostis (E. atrovirens) and lesser dropseed (S. diander), were found to be extremely tolerant, and were not controlled even at the highest salinity level of 72 dS m/sup -1/. P. vaginatum and E. atrovirens did not show significant decrease in shoot and root dry weight at highest salinity levels (72 dS m/sup -1/). The results indicate that sea water has excellent potential for sustainable control of several common grassy weeds in tropical turf. (author)

  8. Chemical control of weeds during the acclimatization of in vitro sugarcane plants cv. 'CP52-43'

    Directory of Open Access Journals (Sweden)

    Inoel García Ruiz

    2016-07-01

    Full Text Available Control of weeds in the acclimatization phase of in vitro sugarcane (Saccharum spp. plants is done manually which raises the cost of production. In order to determine the effectiveness of the chemical control of weeds with Dual Gold CE 96 (Mesotrione, in vitro plants of sugar cane cv. 'CP52-43' were acclimatized in worm humus and cachaça compost. Doses of 0.5, 1.0 and 1.5 l ha-1 p.c. Dual Gold CE 96 herbicide, were applied before and immediately to in vitro plants transplantation and the results were compared to manual weeding. After 50 days of culture, 15 plants were extracted per treatment and the number of leaves and shoots were quantified, the length was measured and the fresh mass of the aerial part and of the roots were determined. The results showed that Dual Gold CE 96 at doses of 0.5 l ha-1 applied before or after transplant, controls the weeds Portulaca oleracea (L., Amaranthus sp. (Mart, Sida acuta (Burm. F. and Eleusine indica (L., without affecting the growth of sugarcane cv. ‘CP52-43’ plants, compared to manual weeding.   Keywords: herbicides, Saccharum, substrate, survival

  9. Marker allergens of weed pollen - basic considerations and diagnostic benefits in the clinical routine: Part 16 of the Series Molecular Allergology.

    Science.gov (United States)

    Stemeseder, Teresa; Hemmer, Wolfgang; Hawranek, Thomas; Gadermaier, Gabriele

    The term weed is referring to plants used as culinary herbs and medicinal plants as well as ecologically adaptive and invasive segetal plants. In Europe, pollen of ragweed, mugwort, English plantain and pellitory are the main elicitors of weed pollen allergies. Presently, 35 weed pollen allergens have been identified. The most relevant belong to the protein families of pectate lyases, defensin-like proteins, non-specific lipid transfer proteins, and Ole e 1-like proteins. The sensitization frequency depends on geographic regions and might affect more than 50 % of pollen allergic patients in distinct regions. Due to overlapping flowering seasons, similar habitats, polysensitizations and cross-reactive (pan)-allergens, it is difficult to diagnose genuine weed pollen sensitization using pollen extracts. Marker allergens for component-resolved diagnostics are available for the important weed pollen. These are Amb a 1 (ragweed), Art v 1 (mugwort), Pla l 1 (English plantain) and Par j 2 (pellitory). Molecule-based approaches can be used to identify the primary sensitizer and thus enable selection of the appropriate weed pollen extracts for allergen immunotherapy.

  10. Allelopathic assessment of selected common weeds in Malaysia

    Science.gov (United States)

    Nurul Ain, M. B.; Nornasuha, Y.; Ismail, B. S.

    2016-11-01

    A laboratory study was conducted to evaluate the allelopathic potential of eight common weed species in Malaysia, namely, Ageratum conyzoides, Tridax procumbens, Cyperus iria, Fimbristylis miliacea, Eleusine indica, Imperata cylindrica, Lygodium flexuosum and Nephrolepis biserrata of different morphological characteristics (broadleaves, sedges, grasses and ferns). The allelopathic study of these weeds was carried out by testing the leaf litter leachate through the Sandwich method and the volatile compounds of these weeds through the Dish pack method with three replicates for each donor species. The results obtained from both methods were statistically analyzed and the means had converted to percentage growth inhibition to determine the inhibition pattern on the radicle and hypocotyl growth of lettuce seedlings. Among the eight weed species tested, Ageratum conyzoides showed the strongest growth inhibition on lettuce radicle elongation (86%) in the sandwich bioassay compared to the control, followed by Tridax procumbens (71%), which both species being broadleaves weeds. In the dish pack bioassay Lygodium flexuosum (fern) demonstrated maximum inhibition on the growth the radicle and hypocotyl for each different distance from the source well. On the other hand, two weed species exhibited enhanced on the growth radicle and hypocotyl when compared to that of the control in dish pack bioassay. Nephrolepis biserrata and Fimbristylis miliacea were the species that showed the highest growth stimulatory effect. The results presented can be utilized as benchmark information for further research on the elucidation of leachates and volatile chemicals involved in allelopathy in nature. The information can also be helpful in the development of new bioactive chemicals from natural products in weed control strategies.

  11. Preliminary Study on Effect of Herbicides on Alfalfa Yield and Weed Community Characteristics in Yellow River Delta, China

    Directory of Open Access Journals (Sweden)

    WANG Guo-liang

    2016-05-01

    Full Text Available Alfalfa(Medicago sativa is one of important legume forages worldwide. However, weed is the main factor limiting alfalfa production. Biomass quality and yield and stability of dry matter production during cultivation are directly associated with the interference of weeds which compete with alfalfa for water, light and nutrients. The use of herbicides is a good alternative for weed control. In order to control weed in alfalfa field with suitable herbicide in Yellow River delta, the effect of four herbicides(imazethapyr, quizalofop-p-ethyl, haloxyfop-r-methyl and oxyfluorfen with different concentration on afalfal yield and weed community characteristics were studied. The results showed that both imazethapyr and haloxyfop-r-methyl treatments could increase alfalfa yield, and the best herbicide application concentration was imazethapyr with 2 000 mL·hm-2 and haloxyfop-r-methyl with 700 mL·hm-2, but oxyfluorfen treatment would limit alfalfa growth significantly. Weed species numbers in the treatments of imazethapyr, quizalofop-p-ethyl and oxyfluorfen decreased significantly. Digitariasanguinalis, Portulacaoleracea and Echinochloacrusgalli were more difficult to control from specie important value in all treatments. Species diversity index decreased with higher herbicide concentration in all treatments. From this study, herbicide imazethapyr with 2 000 mL·hm-2 application concentration was the best weed control method, and the second one was haloxyfop-r-methyl with 700 mL·hm-2 application concentration.

  12. Pest Control in Corn and Soybeans: Weeds - Insects - Diseases.

    Science.gov (United States)

    Doersch, R. E.; And Others

    This document gives the characteristics and application rates for herbicides used to control annual weeds in corn, annual and perennial broadleaf weeds in corn, quackgrass and yellow nutsedge in corn, and annual weeds in soybeans. It also gives insecticide use information for corn and soybeans. A brief discussion of disease control in corn and…

  13. Comparisons of weed community, soil health and economic performance between wheat-maize and garlic-soybean rotation systems under different weed managements

    Directory of Open Access Journals (Sweden)

    Mahmud A. Muminov

    2018-05-01

    Full Text Available This study compared the impacts of different weed managements on weed community, soil health and economic performance between the wheat–maize (WM and garlic–soybean (GS rotations. A total of four treatments (H0T, tillage without herbicide; H0T0, without both herbicide and tillage; HT, both herbicide and tillage; HT0, herbicide without tillage were designed for both rotations. A total of 16 weed species were recorded in the WM rotation, with life forms of 62% for annuals, 12% for annual + perennial and 20% for perennials. While in the GS rotation, there were 17 weed species, with 71% being annuals. When crop rotation changed from WM to GS, the topsoil layer seed bank (0–5 cm decreased by 137%. GS rotation always had higher earthworm densities than that of WM under the same condition. Organic weed control (H0T, H0T0 from both WM and GS added more soil organic matters than the chemical methods (HT and HT0. Economically, up to 69% higher net profit had been achieved in the GS than WM for their organic products. This study provides an ecological basis to guide organic farming practices, especially for weed management in the future.

  14. Weeds in spring cereal fields in Finland - a third survey

    Directory of Open Access Journals (Sweden)

    J. SALONEN

    2008-12-01

    Full Text Available A survey of weeds in spring cereal fields was conducted in 16 regions of southern and central Finland in 1997-1999. Data were collected from conventional and organic farms, both of which applied their normal cropping practices. A total of 690 fields were investigated by counting and weighing the weed species from ten sample quadrats 0.1 m2 in size in late July - early August. Altogether 160 weed species were found, of which 134 were broad-leaved and 26 grass species. The total number of weed species ranged from 41 to 84 between regions. In organically farmed fields, the average species number was 24 and in conventionally farmed fields 16. The most frequent weed species were Viola arvensis 84%, Stellaria media 76% and Galeopsis spp. 70%. Only 18 species exceeded the frequency level of 33%. The average density of weeds was 136 m-2 (median= 91 in sprayed conventional fields, 420 m-2 (374 in unsprayed conventional fields and 469 m-2 (395 in organic fields. The average air-dry above-ground biomass of weeds was 163 kg ha-1 (median=63, 605 kg ha-1 (413 and 678 kg ha-1 (567, respectively. Weed biomass accounted for 3% of the total biomass of the crop stand in sprayed conventional fields and for 17% in organic fields. Elymus repens, the most frequent grass species, produced the highest proportion of weed biomass.

  15. Optical Sensing of Weed Infestations at Harvest.

    Science.gov (United States)

    Barroso, Judit; McCallum, John; Long, Dan

    2017-10-19

    Kochia ( Kochia scoparia L.), Russian thistle ( Salsola tragus L.), and prickly lettuce ( Lactuca serriola L.) are economically important weeds infesting dryland wheat ( Triticum aestivum L.) production systems in the western United States. Those weeds produce most of their seeds post-harvest. The objectives of this study were to determine the ability of an optical sensor, installed for on-the-go measurement of grain protein concentration, to detect the presence of green plant matter in flowing grain and assess the potential usefulness of this information for mapping weeds at harvest. Spectra of the grain stream were recorded continuously at a rate of 0.33 Hz during harvest of two spring wheat fields of 1.9 and 5.4 ha. All readings were georeferenced using a Global Positioning System (GPS) receiver with 1 m positional accuracy. Chlorophyll of green plant matter was detectable in the red (638-710 nm) waveband. Maps of the chlorophyll signal from both fields showed an overall agreement of 78.1% with reference maps, one constructed prior to harvest and the other at harvest time, both based on visual evaluations of the three green weed species conducted by experts. Information on weed distributions at harvest may be useful for controlling post-harvest using variable rate technology for herbicide applications.

  16. Parthenium weed (Parthenium hysterophorus L.) and climate change: the effect of CO2 concentration, temperature, and water deficit on growth and reproduction of two biotypes.

    Science.gov (United States)

    Nguyen, Thi; Bajwa, Ali Ahsan; Navie, Sheldon; O'Donnell, Chris; Adkins, Steve

    2017-04-01

    Climate change will have a considerable impact upon the processes that moderate weed invasion, in particular to that of parthenium weed (Parthenium hysterophorus L.). This study evaluated the performance of two Australian biotypes of parthenium weed under a range of environmental conditions including soil moisture (100 and 50% of field capacity), atmospheric carbon dioxide (CO 2 ) concentration (390 and 550 ppm), and temperature (35/20 and 30/15 °C/day/night). Measurements were taken upon growth, reproductive output, seed biology (fill, viability and dormancy) and soil seed longevity. Parthenium weed growth and seed output were significantly increased under the elevated CO 2 concentration (550 ppm) and in the cooler (30/15 °C) and wetter (field capacity) conditions. However, elevated CO 2 concentration could not promote growth or seed output when the plants were grown under the warmer (35/20 °C) and wetter conditions. Warm temperatures accelerated the growth of parthenium weed, producing plants with greater height biomass but with a shorter life span. Warm temperatures also affected the reproductive output by promoting both seed production and fill, and promoting seed longevity. Dryer soil conditions (50% of field capacity) also promoted the reproductive output, but did not retain high seed fill or promote seed longevity. Therefore, the rising temperatures, the increased atmospheric CO 2 concentration and the longer periods of drought predicted under climate change scenarios are likely to substantially enhance the growth and reproductive output of these two Australian parthenium weed biotypes. This may facilitate the further invasion of this noxious weed in tropical and sub-tropical natural and agro-ecosystems.

  17. The influence of intercrop plants and the date of their ploughing-in on weed infestation of root chicory (Cichorium intybus L. var. sativum (Bisch. Janch.

    Directory of Open Access Journals (Sweden)

    Marzena Błażewicz-Woźniak

    2012-12-01

    Full Text Available The field experiment was carried out in 2006-2008 in the Felin Experimental Farm (University of Life Sciences in Lublin on podzolic soil developed from dusty medium loam. Root chicory (Cichorium intybus L. var. sativum (Bisch. Janch. cv. Polanowicka was involved in the experiment. The experimental factors were 3 species of intercrop plants: common vetch (Vicia sativa, phacelia (Phacelia tanacetifolia, oat (Avena sativa and 2 dates of ploughing-in: pre-winter and spring. In total, 26 taxons characteristic for vegetable plantations were identified in chicory weed infestation. Monocarpic species dominated, among which Senecio vulgaris, Chenopodium album, Lamium amplexicaule, Galinsoga ciliata, and Capsella bursa-pastoris were predominant. The date of ploughing-in did not significantly affect the status and size of weed infestation of chicory plots. Short-lived species occurred after pre-winter ploughing-in, while perennial - after spring ploughing-in. The application of intercrops significantly reduced chicory weed infestation as compared to the cultivation with no intercrop. The ploughing-in of Avena sativa biomass appeared to be the most efficient. The intercrop plants reduced the occurrence of Senecio vulgaris and Capsella bursa-pastoris which were the most numerous in the treatment without intercrops. Biomass of Vicia sativa favored the growth of Chenopodium album and Lamium amplexicaule. The secondary weed infestation did not depend on agrotechnical factors applied during the experiment.

  18. Weeding method and pre-sowing tillage effects on weed growth and pearl millet yield in a sandy soil of the West African Sahelian zone.

    NARCIS (Netherlands)

    Klaij, M.C.; Hoogmoed, W.B.

    1996-01-01

    Weed control for the West African Sahel rainfed crops is done mainly manually, resulting in high labor requirements. Because of the seasonality of rainfed farming, weed control is often late and incomplete, resulting in considerable losses in crop yield. We examined the case of weed control in

  19. On weed competition and population dynamics : considerations for crop rotations & organic farming

    NARCIS (Netherlands)

    Mertens, S.K.

    2002-01-01

    Key words: organic farming, weeds, weed management, weed ecology, weed diversity, matrix population model, elasticity analysis, neighbourhood model, survey, crop row spacing, mechanical hoe, harrow, Polygonum convolvulus ,

  20. The main weed species and their control in oilseed crops in Finland

    Directory of Open Access Journals (Sweden)

    J. SALONEN

    2008-12-01

    Full Text Available A survey of weeds in spring-sown oilseed crops (Brassica rapa ssp. oleifera and Brassica napus ssp. oleifera was conducted in southern and central Finland during 2007–2009, representing the first such extensive investigation in the country. The occurrence of the most abundant weed species in oilseeds was surveyed in 429 fields. In the fields with moderate or high weed infestation, 1–6 harmful weed species were recorded by visual observation according to their biomass production. About 40 weed species were recorded, the most predominant being Chenopodium album, Galeopsis spp., Galium spurium, Sonchus arvensis and Tripleurospermum inodorum. Elymus repens was the only major grass weed. Chemical weed control of broad-leaved weeds had been practised in 53% of the fields, resulting in relatively good control. In addition, both selective graminicides and glyphosate were used to control E. repens. Mechanical weed control was not practised in any field. The crop yield level was about 300 kg ha-1 higher in the fields with low weed infestation compared with in the highly infested fields. New promising options to replace the banned herbicide trifluralin are available. Thus, the most harmful weeds, such as C. album, which interferes with the production of high-quality oil for human consumption, can still be effectively controlled.;

  1. New possibilities for weed control in conventional soybeans

    Directory of Open Access Journals (Sweden)

    Petersen, Jan

    2014-02-01

    Full Text Available In field trials in was investigated, if the use of the in Germany new active ingredient imazamox enlarge the possibilities of post emergence weed control in soybeans. Furthermore new herbicide strategies were tested on efficacy and selectivity in soybeans. The use of imazamox was very selective and showed a relative broad spectrum of controlled weed species. However, efficacy of imazamox must be supported by a pre-emergence treatment and in most cases by a tank mix partner. For example cleavers (Galium aparine can not be controlled by imazamox. Tankmixtures of imazamox and bentazon indicated an antagonism. Efficacy to some weed species was reduced compared to solo application. The low dose concept – three applications of low doses at cotyledon stage of weeds led to some success. However, these strategies must be further investigated, before they can be recommended to commercial farming practice. All herbicide strategies tested showed some surviving weed species. This indicates that choice of herbicides, dose rates and application strategies must be done very careful and site specific.

  2. Alien species in the Finnish weed flora

    Directory of Open Access Journals (Sweden)

    T. HYVÖNEN

    2008-12-01

    Full Text Available The present study aimed at assessing the invasion of alien weed species in Finland based on a review of their occurrence in the Finnish weed flora. The evaluation was conducted for the three phases of the invasion process, i.e. introduction, naturalization and invasion. The literature review revealed that 815 alien weed species occur in Finland of which 314 are regarded as naturalized. Based on their occurrence in different climate zones, the risk of naturalization of new harmful alien weed species was deemed low for those species not currently found in Finland, but higher for species occurring as casual aliens in Finland. In the latter group, 10 species of concern were detected. Exploration of the distribution patterns of naturalized species within Finland revealed species occupancy to be dependent on the residence time of the species. Established neophytes can be expected to extend their ranges and to increase occupation of agricultural habitats in the future.;

  3. Microwave Technologies as Part of an Integrated Weed Management Strategy: A Review

    Directory of Open Access Journals (Sweden)

    Graham Brodie

    2012-01-01

    Full Text Available Interest in controlling weed plants using radio frequency or microwave energy has been growing in recent years because of the growing concerns about herbicide resistance and chemical residues in the environment. This paper reviews the prospects of using microwave energy to manage weeds. Microwave energy effectively kills weed plants and their seeds; however, most studies have focused on applying the microwave energy over a sizable area, which requires about ten times the energy that is embodied in conventional chemical treatments to achieve effective weed control. A closer analysis of the microwave heating phenomenon suggests that thermal runaway can reduce microwave weed treatment time by at least one order of magnitude. If thermal runaway can be induced in weed plants, the energy costs associated with microwave weed management would be comparable with chemical weed control.

  4. The role of plant-microbiome interactions in weed establishment and control.

    Science.gov (United States)

    Trognitz, Friederike; Hackl, Evelyn; Widhalm, Siegrid; Sessitsch, Angela

    2016-10-01

    The soil microbiome plays an important role in the establishment of weeds and invasive plants. They associate with microorganisms supporting their growth and health. Weed management strategies, like tillage and herbicide treatments, to control weeds generally alter soil structure going alongside with changes in the microbial community. Once a weed population establishes in the field, the plants build up a close relationship with the available microorganisms. Seeds or vegetative organs overwinter in soil and select early in the season their own microbiome before crop plants start to vegetate. Weed and crop plants compete for light, nutrition and water, but may differently interact with soil microorganisms. The development of new sequencing technologies for analyzing soil microbiomes has opened up the possibility for in depth analysis of the interaction between 'undesired' plants and crop plants under different management systems. These findings will help us to understand the functions of microorganisms involved in crop productivity and plant health, weed establishment and weed prevention. Exploitation of the knowledge offers the possibility to search for new biocontrol methods against weeds based on soil and plant-associated microorganisms. This review discusses the recent advances in understanding the functions of microbial communities for weed/invasive plant establishment and shows new ways to use plant-associated microorganisms to control weeds and invasive plants in different land management systems. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Germination of some important weeds influenced by red light and nitrogenous compounds

    International Nuclear Information System (INIS)

    Tanfg, Dong-Seng; Hamayun, M.; Khan, A.L.; Shinwari, Z.K.; Kim, H.A.; Yoon-Ha; Kang, Sang-Mo; Lee, Joon-Hee; Chae-In; Nawaz, Y.; Kang, Kee-Kyung; Lee, In-Jung

    2010-01-01

    Seed dormancy is a major constraint in the eradication of weeds from agriculture fields. Seeds of Amaranthus retroflexus, Echinocloa crus-galli and Digitaria adscendens were collected from cultivated fields, dried and then treated with different nitrogen containing compounds i.e., potassium nitrate, ammonium chloride, ammonium nitrate and sodium nitrite. Some seeds were kept under dark while others were irradiated with red light for 10 min., after 12 hr of inhibition. The N-compounds were applied at the rate of 1, 5, 10, 25 and 50 mM, while the strength of red light pulse was maintained at 80 mu mols/sup -2/m/sup -1/. It was observed that red light significantly improved germination rates of A. retroflexus, E. crus-galli and D. adscendens. Nitrogenous compounds significantly improved germination of weeds and maximum germination was induced by ammonium nitrate. However, exposure of seeds to both red light and N-compounds provided significantly higher germination as compared to singular application of either of them. E. crusgalli recorded highest germination rates in response to red light and N-compounds, while D. adscendens provided least values for the same treatments. Application of N-compounds in conjunction with red light significantly improves germination rates of selected weed species by breaking their dormancy. (author)

  6. Predicting weed problems in maize cropping by species distribution modelling

    Directory of Open Access Journals (Sweden)

    Bürger, Jana

    2014-02-01

    Full Text Available Increasing maize cultivation and changed cropping practices promote the selection of typical maize weeds that may also profit strongly from climate change. Predicting potential weed problems is of high interest for plant production. Within the project KLIFF, experiments were combined with species distribution modelling for this task in the region of Lower Saxony, Germany. For our study, we modelled ecological and damage niches of nine weed species that are significant and wide spread in maize cropping in a number of European countries. Species distribution models describe the ecological niche of a species, these are the environmental conditions under which a species can maintain a vital population. It is also possible to estimate a damage niche, i.e. the conditions under which a species causes damage in agricultural crops. For this, we combined occurrence data of European national data bases with high resolution climate, soil and land use data. Models were also projected to simulated climate conditions for the time horizon 2070 - 2100 in order to estimate climate change effects. Modelling results indicate favourable conditions for typical maize weed occurrence virtually all over the study region, but only a few species are important in maize cropping. This is in good accordance with the findings of an earlier maize weed monitoring. Reaction to changing climate conditions is species-specific, for some species neutral (E. crus-galli, other species may gain (Polygonum persicaria or loose (Viola arvensis large areas of suitable habitats. All species with damage potential under present conditions will remain important in maize cropping, some more species will gain regional importance (Calystegia sepium, Setara viridis.

  7. Aquatic weeds: their implications in Indian nuclear industry

    International Nuclear Information System (INIS)

    Rao, T.S.; Anup Kumar, B.; Aruna Jyothi, K.; Satpathy, K.K.

    2000-01-01

    The aquatic weed infestation of KAPS cooling water system, MAPS open reservoir, and the growth of filamentous algae and bacteria in the feed water unit of HWP (Kota), was investigated. The aquatic weeds identified were: Ceratophyllum, Elodea, Hydrilla verticillata, Najas and Vallisneria species. However, at HWP (Kota) filamentous alga (Nostoc punchiformis) and bacteria (Sphaerotilus natans) were found in plenty. The metabolic products when assayed in the form of total carbohydrate content released by weeds was 3.7 mg gm -1 biomass. The metabolic products adsorb on to the resin matrix and impaired its performance at HWP (K), enhanced bacterial growth on the resin beads and furthered resin deterioration. Besides, the growth of aquatic weeds also influenced the pH of the cooling water, thereby vitiating the water treatment programme. (author)

  8. Weed management practices in natural ecosystems: a critical overview

    Directory of Open Access Journals (Sweden)

    C.F. Reinhardt

    2000-07-01

    Full Text Available Increasing public pressure against the use of pesticides and other agricultural inputs has placed increased emphasis on the development of ecologically based pest management. One distinct reaction of the Weed Science discipline has been the swing away from herbicide research to increased research on the basic biology and ecology of weeds in hopes of reduced reliance on "technological crutches" such as herbicides and other practices that are potentially harmful to the environment. Biological control is the long-standing alternative to the use of herbicides and interest in the former practice has been boosted by the realization that the use of herbicides may lead to the development of herbicide resistance in weed populations, and that herbicide residues occur in surface and groundwater. Supporters of herbicide use would point out that biological control is generally not effective in crop production systems, and is basically slow-acting. Debates between protagonists for the exclusive use of one or the other weed management practice tend to obscure the benefits that integration of different techniques are likely to have. For natural ecosystems it is proposed that integration of the more subtle practice of biological control with the use of herbicides, which relatively quickly overwhelm a biological system with mortality, is likely to be the most effective weed management tool. Different weed management practices that could be considered in natural ecosystems are discussed in terms of three key performance rating criteria, viz. activity, selec- tivity and persistence In this concise review, general discussion is focussed on the fundamentals of weed management practices, with the view to promote concept-based approaches that are critical for the development of effective weed management strate- gies.

  9. Potential Use of Essential oils from Four Tunisian Species of Lamiaceae: Biological Alternative for Fungal and Weed Control

    Directory of Open Access Journals (Sweden)

    Mohsen Hanana

    2017-05-01

    Full Text Available The chemical composition of the essential oils (EOs of four Lamiaceae (Thymus capitatus Hoff. et Link. , Rosmarinus officinalis L., Origanum vulgare L. and Mentha pulegium L. growing wild in Tunisia was analyzed by gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS. Obtained results showed significant variations among the different species. The major constituents identified for each species were respectively carvacrol (69% and δ-terpinene (17% for T. capitatus, 1,8-cineole (41% and α-pinene (24% for R. officinalis, menthol (39% and 1.8-cineole (17% for M. pulegium , thymol (30%, p-cymene (30% and δ-terpinene (27% for O. vulgare . EO herbicidal effects were evaluated against three invasive weed species in most cultivated crops: Sinapis arvensis L., Phalaris paradoxa L. and Lolium rigidum Gaud. The study of herbicidal activity was carried out on seed germination and seedling vigor and growth. All tested EOs significantly inhibited the germination and growth of weeds in a dose dependent manner and their herbicidal activity could be attributed mainly to their high content in oxygenated monoterpenes. The antifungal ability of EOs was assessed by using disc agar diffusion against ten plant pathogenic fungi affecting crops and stored foods. The EOs displayed strong inhibitory effect on all tested fungi. Our results on EOs chemical composition and biological activities showed properties that could be valorized in managing biocontrol of weeds and plant fungi.

  10. Robust Crop and Weed Segmentation under Uncontrolled Outdoor Illumination

    Directory of Open Access Journals (Sweden)

    Hong Y. Jeon

    2011-06-01

    Full Text Available An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN. The developed algorithm was validated for its ability to identify and detect weeds and crop plants under uncontrolled outdoor illuminations. A machine vision implementing field robot captured field images under outdoor illuminations and the image processing algorithm automatically processed them without manual adjustment. The errors of the algorithm, when processing 666 field images, ranged from 2.1 to 2.9%. The ANN correctly detected 72.6% of crop plants from the identified plants, and considered the rest as weeds. However, the ANN identification rates for crop plants were improved up to 95.1% by addressing the error sources in the algorithm. The developed weed detection and image processing algorithm provides a novel method to identify plants against soil background under the uncontrolled outdoor illuminations, and to differentiate weeds from crop plants. Thus, the proposed new machine vision and processing algorithm may be useful for outdoor applications including plant specific direct applications (PSDA.

  11. Onion and weed response to mustard (Sinapis alba) seed meal

    Science.gov (United States)

    Weed control in organic onion production is often difficult and expensive, requiring numerous cultivations and extensive hand-weeding. Onion safety and weed control with mustard seed meal (MSM) derived from Sinapis alba was evaluated in greenhouse and field trials. MSM applied at 110, 220, and 440 g...

  12. Evaluation of UAV imagery for mapping Silybum marianum weed patches

    Science.gov (United States)

    The invasive weed, milk thistle (Silybum marianum), has the tendency to grow in patches. In order to perform site-specific weed management, determining the spatial distribution of weeds is important for its eradication. Remote sensing has been used to perform species discrimination, and it offers pr...

  13. Performance of weed Extracts on Growth Characteristics and Biochemical Activities in Salt Stressed Soybean Plants

    International Nuclear Information System (INIS)

    Moussa, H.R.; Khodary, S.E.A.

    2004-01-01

    The changes induced in the growth parameters and certain metabolic activities in response to both salt (NaCI) shock treatments and foliar spray of weed extracts (jungle rice, cocklebur and purslane) plus salinity were studied, using soybean seedlings grown in Hoagland's nutrient solution supplemented with various concentrations of NaCI. When seedlings were subjected to high salinity (100 and 200 mM NaCI), their growth criteria, the photosynthetic capacity, pigment contents and carbohydrate metabolism were significantly decreased. Under salinized conditions and weed extract treatments, the growth pattern,''1''4CO 2 -fixation rate, pigment as well as carbohydrate contents of soybean plants were significantly increased comparable to NaCI-treated samples. It was suggested that weed extract and in particular jungle rice might oppose the harsh effect of salinity in soybean plants

  14. Evaluation of biomass of some invasive weed species as substrate for oyster mushroom (Pleurotus spp.) cultivation.

    Science.gov (United States)

    Mintesnot, Birara; Ayalew, Amare; Kebede, Ameha

    2014-01-15

    This study assessed the bioconversion of Agriculture wastes like invasive weeds species (Lantana camara, Prosopis juliflora, Parthenium hysterophorus) as a substrate for oyster mushroom (Pleurotus species) cultivation together with wheat straw as a control. The experiment was laid out in factorial combination of substrates and three edible oyster mushroom species in a Completely Randomized Design (CRD) with three replications. Pleurotus ostreatus gave significantly (p mushroom cultivation could contribute to alleviating ecological impact of invasive weed species while offering practical option to mitigating hunger and malnutrition in areas where the invasive weeds became dominant.

  15. An autonomous weeding robot for organic farming

    NARCIS (Netherlands)

    Bakker, T.; Asselt, van C.J.; Bontsema, J.; Müller, J.; Straten, van G.

    2006-01-01

    The objective of this research is the replacement of hand weeding in organic farming by a device working autonomously at ¯eld level. The autonomous weeding robot was designed using a structured design approach, giving a good overview of the total design. A vehicle was developed with a diesel engine,

  16. Effectiveness of weed control methods on pavement

    NARCIS (Netherlands)

    Vermeulen, G.D.; Verwijs, B.R.; Kempenaar, C.

    2007-01-01

    The policy in the Netherlands is to signifiantly reduce the use of herbicides, also on pavements. Existing non-chemical methods to control weeds are much less effective than spot spraying, the usual method at this moment. Therefore, the cost of non-chemical weed management is often estimated to be 4

  17. Structural and Functional Diversity of Weed Species in Organic and Conventional Rice Agro-Ecosystems

    Directory of Open Access Journals (Sweden)

    S. Y. Mousawi Toghani

    2016-02-01

    -Wilson included two clusters in 83% and 82%, respectively. Range of similarity index was between 1.89% and 83.96%. Weed grouping based on relative frequency during the sampling stages showed two clusters in 78% and four clusters in 85% similarity. Clustering weeds centered on relative frequency during sampling stages, according to the family, showed different results. It might be the reason that the relative abundance of weeds, sedge family (79% were in two clusters. However, sampling stages grouping based on weed density, induced two clusters in 39% similarity. Both conventional and organic systems, are included 10 species of 8 genera of four families. The 75 percent of families based on the vegetative form were monocots and 25% of them were dicots, so monocots had more diversity. Perhaps the presence of Alismaplantagoin the conventional system could be as a unique species and its absence in the organic system, attributable to duck existence in it. Based on life-cycle, 6 species were annual and 4 were perennial. While, according to the photosynthetic pathway, 50 percent species were C3 and others had C4 pathway. Based on the characteristics of the interference, 4 species were noxious and 6 species were non-noxious. Poaceae were the most diversity of weeds in monocotyledon and C4 pathway (three species. Two species of noxious weeds and herbicide resistant belong to Poaceae too. The Cyperaceae consist of two species from four perennial ones. The weeds of Poaceae and Cyperaceae families include 70% of total weed. Generally, weeds in ecosystems usually change thehabitat conditions or impact on the resources availability for other species. Conclusions Due to repeated or severe disturbances, agro-ecosystems are limited to the early stages of succession. Thus, the widespread destruction of agro-ecosystems during consecutive years, by changing the succession, weed population dynamics was affected as well. It should be noted that the differences of weed distribution in the various stages

  18. Effect of Cover Crops and Nitrogen Fertilizer on Total Production of Forage Corn and Dry Weight of Weeds

    Directory of Open Access Journals (Sweden)

    R Fakhari

    2014-10-01

    Full Text Available To evaluate the effect of cover crops, split application of nitrogen and control weeds on forage corn and weed biomass a factorial experiment based on randomized complete block design with three replications and three factors was conducted at the Agricultural Research Station of Ardabil (Iran during 2012 crop year. The first factor was cover crops (consisting of winter rye, hairy vetch, berseem clover, with and without weeding as controls. The second factor was two levels of split application of 225 kg.ha-1 urea at two growth stages forage corn: the first level (N1= 1/2 at planting and 1/2 at 8-10 leaf stage, second level (N2= 1/3 at planting, 1/3 at 8-10 leaf and 1/3 one week before tasselling stage. The third factor consisted of two levels of weed control: weeding at 8 leaves and weeding one week before tasselling. Results showed that winter rye, hairy vetch and berseem clover cover crops decreased total weed dry weights up to 87, 82 and 65 % respectively as compared to control (without weeding. Cover crops and nitrogen application time had a significant effect on yield of fresh forage corn and cover crops. Based on the advantages of effective weed control and higher forage production of hairy vetch it can be recommended as proper cover crop.

  19. A New Hoe Blade for Inter-Row Weeding

    DEFF Research Database (Denmark)

    Green, O.; Znova, L.; Melander, Bo

    2016-01-01

    and weeds are relatively small. The term ‘Ducksfoot’ covers a range of hoe blade configurations where all have some resemblance with the shape of a ducks foot. However, the ‘Ducksfoot’ blade is not an optimal solution for weed control in narrow inter-row spaces. Several disadvantages have been encountered...... and the draft forces needed to pull it were approx. half those measured for a ‘Ducksfoot’ blade. The weeding features of the new L-blade will be further studied under field conditions....

  20. Strip Tillage and Early-Season Broadleaf Weed Control in Seeded Onion (Allium cepa

    Directory of Open Access Journals (Sweden)

    Sarah Gegner-Kazmierczak

    2016-03-01

    Full Text Available Field experiments were conducted in 2007 and 2008 near Oakes, North Dakota (ND, USA, to evaluate if strip tillage could be incorporated into a production system of seeded onion (Allium cepa to eliminate the standard use of a barley (Hordeum vulgare companion crop with conventional, full width tillage, yet support common early-season weed control programs. A split-factor design was used with tillage (conventional and strip tillage as the main plot and herbicide treatments (bromoxynil, DCPA, oxyfluorfen, and pendimethalin as sub-plots. Neither tillage nor herbicide treatments affected onion stand counts. Common lambsquarters (Chenopodium album densities were lower in strip tillage compared to conventional tillage up to three weeks after the post-emergence applied herbicides. In general, micro-rate post-emergence herbicide treatments provided greater early-season broadleaf weed control than pre-emergence herbicide treatments. Onion yield and grade did not differ among herbicide treatments because the mid-season herbicide application provided sufficient control/suppression of the early-season weed escapes that these initial weed escapes did not impact onion yield or bulb diameter. In 2007, onion in the strip tillage treatment were larger in diameter resulting in greater total and marketable yields compared to conventional tillage. Marketable onion yield was 82.1 Mg ha−1 in strip tillage and 64.9 Mg ha−1 in conventional tillage. Results indicate that strip tillage use in direct-seeded onion production was beneficial, especially when growing conditions were conducive to higher yields and that the use of strip tillage in onion may provide an alternative to using a companion crop as it did not interfere with either early-season weed management system.

  1. Crop diversity prevents serious weed problems

    DEFF Research Database (Denmark)

    Melander, Bo

    2016-01-01

    Weed management in organic crop production could benefit from more diversification of today’s cropping systems. However, the potential of diversification needs better documentation and solid suggestions for employment in practise must be identified.......Weed management in organic crop production could benefit from more diversification of today’s cropping systems. However, the potential of diversification needs better documentation and solid suggestions for employment in practise must be identified....

  2. Integrated pest management and weed management in the United States and Canada.

    Science.gov (United States)

    Owen, Micheal D K; Beckie, Hugh J; Leeson, Julia Y; Norsworthy, Jason K; Steckel, Larry E

    2015-03-01

    There is interest in more diverse weed management tactics because of evolved herbicide resistance in important weeds in many US and Canadian crop systems. While herbicide resistance in weeds is not new, the issue has become critical because of the adoption of simple, convenient and inexpensive crop systems based on genetically engineered glyphosate-tolerant crop cultivars. Importantly, genetic engineering has not been a factor in rice and wheat, two globally important food crops. There are many tactics that help to mitigate herbicide resistance in weeds and should be widely adopted. Evolved herbicide resistance in key weeds has influenced a limited number of growers to include a more diverse suite of tactics to supplement existing herbicidal tactics. Most growers still emphasize herbicides, often to the exclusion of alternative tactics. Application of integrated pest management for weeds is better characterized as integrated weed management, and more typically integrated herbicide management. However, adoption of diverse weed management tactics is limited. Modifying herbicide use will not solve herbicide resistance in weeds, and the relief provided by different herbicide use practices is generally short-lived at best. More diversity of tactics for weed management must be incorporated in crop systems. © 2014 Society of Chemical Industry.

  3. How Local Landholder Groups Collectively Manage Weeds in South-Eastern Australia

    Science.gov (United States)

    Graham, Sonia; Rogers, Sarah

    2017-09-01

    For two decades researchers and policy makers have been arguing that community-based collective action is needed to effectively control weeds. Yet there has been little social research into the ways that collective weed control emerges at local scales. The aim of this paper is to investigate the mechanisms through which three local landholder groups in south-eastern Australia collectively manage weeds and the measures they use to evaluate success. Semi-structured interviews were conducted with members of three Landcare groups—Jerrawa Creek/Upper Lachlan, MacLaughlin River and Towamba Valley—as well as government staff external to the groups. The results reveal that for all three groups collective weed control is about supporting individual weed control efforts as well as proactively engaging landholders with the worst infestations. The groups were seen to be successful because they focused on the common challenge that weeds pose to all landholders, thereby removing the shame associated with having weeds, and because they organised community events that were as much about building and maintaining social relationships as improving weed control. Groups were positive about what they had achieved as collectives of landholders, but also saw an important role for government in providing funding, engaging with landholders who were unwilling to engage directly with the group, and controlling weeds on public lands.

  4. Weed control technology for environmentally, economically and socially sustainable agriculture

    International Nuclear Information System (INIS)

    Khan, A.R.; Srivastava, R.C.; Ghorai, A.K.; Singh, S.R.

    2001-04-01

    Studies were conducted through a series of experiments for five consecutive wet seasons with a variety of alternative biological weed control techniques by means of soil solarization. This is a method of heating soil surface by using transparent polyethylene sheets placed on soil surface to trap solar radiation. This raises soil temperature to a level lethal for many soil borne pathogens and weed seeds, thus killing weeds before crop emergence. The use of black low density polyethylene sheets reduces weed growth and increases rice yield

  5. Weed control technology for environmentally, economically and socially sustainable agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A R [Directorate of Water Management Research, Indian Council of Agricultural Research (ICAR), Walmi Complex, Phulwari Sharif, Patna, Bihar (India); [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Srivastava, R C [Water Technology Centre for Eastern Region (ICAR), Bhubaneswar (India); Ghorai, A K [CRIJAF (ICAR), Barrackpore, West Bengal (India); Singh, S R [Directorate of Water Management Research, Indian Council of Agricultural Research (ICAR), Walmi Complex, Phulwari Sharif, Patna, Bihar (India)

    2001-04-01

    Studies were conducted through a series of experiments for five consecutive wet seasons with a variety of alternative biological weed control techniques by means of soil solarization. This is a method of heating soil surface by using transparent polyethylene sheets placed on soil surface to trap solar radiation. This raises soil temperature to a level lethal for many soil borne pathogens and weed seeds, thus killing weeds before crop emergence. The use of black low density polyethylene sheets reduces weed growth and increases rice yield.

  6. Capabilities of unmanned aircraft vehicles for low altitude weed detection

    Science.gov (United States)

    Pflanz, Michael; Nordmeyer, Henning

    2014-05-01

    Sustainable crop production and food security require a consumer and environmental safe plant protection. It is recently known, that precise weed monitoring approaches could help apply pesticides corresponding to field variability. In this regard the site-specific weed management may contribute to an application of herbicides with higher ecologically aware and economical savings. First attempts of precision agriculture date back to the 1980's. Since that time, remote sensing from satellites or manned aircrafts have been investigated and used in agricultural practice, but are currently inadequate for the separation of weeds in an early growth stage from cultivated plants. In contrast, low-cost image capturing at low altitude from unmanned aircraft vehicles (UAV) provides higher spatial resolution and almost real-time processing. Particularly, rotary-wing aircrafts are suitable for precise path or stationary flight. This minimises motion blur and provides better image overlapping for stitching and mapping procedures. Through improved image analyses and the recent increase in the availability of microcontrollers and powerful batteries for UAVs, it can be expected that the spatial mapping of weeds will be enhanced in the future. A six rotors microcopter was equipped with a modified RGB camera taking images from agricultural fields. The hexacopter operates within predefined pathways at adjusted altitudes (from 5 to 10 m) by using GPS navigation. Different scenarios of optical weed detection have been carried out regarding to variable altitude, image resolution, weed and crop growth stages. Our experiences showed high capabilities for site-specific weed control. Image analyses with regard to recognition of weed patches can be used to adapt herbicide application to varying weed occurrence across a field.

  7. Effect of the Critical Period of Weed Interference on Optimum ...

    African Journals Online (AJOL)

    A field study was carried out at the National Root Crop Research Institute experimental farm to determine the critical period of weed interference and magnitude of yield loss caused by weed on turmeric in 2008 and 2009 cropping season. Turmeric was subjected to 13 weeding regimes using randomized complete block ...

  8. Distribution patterns of segetal weeds of cereal crops in tajikistan

    International Nuclear Information System (INIS)

    Nowak, A.; Nowak, S.

    2015-01-01

    Using the literature data and field research conducted in 2009-2013 the distribution patterns, habitat conditions, phytogeographical characterisation and endangerment of weeds occurring in cereal crops in Tajikistan were analysed. We found out that Tajik weed flora of cereal crops counts 686 taxa. The most species rich families include Asteraceae, Poaceae and Fabaceae. The highest number of cereal weeds were noted in large river valleys of Syr-Daria, Amu-Daria and their tributaries in south-western and northern Tajikistan. This subregions have the warmest climate conditions and extensive arable lands. The greatest weed species richness was observed in submontane and montane elevations between approx. 700 and 1,900 m a.s. Cereal weeds occur frequently outside segetal communities in Tajikistan. They were noted usually in screes, wastelands, xerothermophilous grasslands, river gravel beds and in steppes habitats. The assessment of threat status reveals that ca. 33% of total cereal weed flora in Tajikistan are disappearing or occur very rarely. According to the chorological data we find that in the cereals of Tajikistan, 35 endemic and 14 subendemic species occur. The most numerous chorological elements of threatened weed flora of Tajikistan are Irano-Turanian (55%), pluriregional (16%), cosmopolitan (14,5%), Mediterranean (9%) and Eurosiberian (5%) species. Further research is suggested to explore the distribution patterns of all weed species in Tajikistan as it should be useful for economy and effectiveness of crop production as well as conservation of most valuable species. (author)

  9. Researches regarding glyphosate effectiveness on the degree of weed control in grape plantation

    Directory of Open Access Journals (Sweden)

    Monica NEGREA

    2010-11-01

    Full Text Available In this paper was determined the control degree of weeds in grape plantation, Burgund variety, when is using chemical treatments with herbicides and agro-technique measures. Herbicide used was Roundup 3 l/ha and 4l/ha (glyphosate isopropyl amine salt 360 g/l applied in 4 experimental variants. It was determined the weed presence degree, the type of weeds destroyed and the degree of their participation. Predominant weed species in studied grape plantation, were: Agropyron repens (20.15%, Geranium dissectum (17.91%, Capsella bursa pastoris (15.67% and Avena fatua (13.43%. Ephemeral weeds Veronica hederifolia and Stellaria media had a participation rate of 8.96%. Perennial weeds represented 40.30% while annual weeds are 59.70% . The herbicide Roundup provides most effective control in a dose of 3 or 4 l/ha, combined with mechanical weeding + 1 manual weeding, control rates being over 90%.

  10. Herbicide on Weed Composition, Diversity and Density in Silage Corn (cv. Sc 704

    Directory of Open Access Journals (Sweden)

    M. Zafarian

    2012-07-01

    Full Text Available In order to study the effect of plant density, planting pattern and herbicide dosage of nicosulfuron, a field experiment was arranged in a factorial split plot treatments based on RCBD with three replications in Chenaran, Khorasan Razavi, in 2010. The experimental treatments consisted of a factorial plant density (100000, 120000 and 140000 plants ha-1 in the planting pattern (single and double row as main plot and herbicide dosage of nicousulforon in four levels (0, 1, 1/5 and 2, l.ha-1 as sub-plot. Samplings were made at in five stages (37days after the emergence of corn and it was repeated once per 20 days. The results indicated reducing the weed density and dry matter of weeds in the first stage after the herbicide treatment. Moreover, it was observed a significant interaction effect between plant density with planting pattern and between planting pattern with herbicides dosages during growth season on reducing weed density and dry matter. Also results indicated that in between of this experiment's treatments, nicosulfuron herbicide reduced weed density at the beginning of growth season and double row planting pattern suppressed weed density during growing season, and resulted in lowest Jacard similarity index (Sj of weed species. Results also indicated that with increasing of plant density and herbicide dosage especially in composition of double row planting pattern, according to Shannon- Wiener index, sensitive population such as common purslane (Portulaca oleracea L., buckhorn plantain (Plantago lanceolata L., prostrate knotweed (Polygonum aviculareL., black nightshade (Solanum nigrum L. and Johnson grass (Sorghum halepens L. was reduced in during growing season. Simpson dominance index, showed that some low populated weeds such as redroot pigweed (Amaranthus retroflexus L., common lambsquarters (Chenopodium album L., field bindweed (Convolvulus arvensis L. and Canada thistle (Circum arvensis L. persisted their growth up to the end of

  11. Controlling grass weeds on hard surfaces

    DEFF Research Database (Denmark)

    Rask, Anne Merete; Kristoffersen, Palle; Andreasen, Christian

    2012-01-01

    An experiment was conducted on a specially designed hard surface to study the impact of time interval between flaming treatments on the regrowth and flower production of two grass weeds. The goal of this experiment was to optimize the control of annual bluegrass and perennial ryegrass, both species...... that are very difficult to control without herbicides. Aboveground biomass from 72 plants per treatment was harvested and dry weights were recorded at regular intervals to investigate how the plants responded to flaming. Regrowth of the grasses was measured by harvesting aboveground biomass 2 wk after......, as they did not increase the reduction of aboveground biomass compared with the 7-d treatment interval. Knowledge on the regrowth of grass weeds after flaming treatments provided by this study can help improve recommendations given to road keepers and park managers for management on these weeds. Nomenclature...

  12. Airway wall thickness of allergic asthma caused by weed pollen or house dust mite assessed by computed tomography.

    Science.gov (United States)

    Liu, Liping; Li, Guangrun; Sun, Yuemei; Li, Jian; Tang, Ningbo; Dong, Liang

    2015-03-01

    Little was known about Airway wall thickness of asthma patients with different allergen allergy. So we explored the possible difference of Airway wall thickness of asthma patients mono-sensitized to weed pollen or HDM using high-resolution computed tomography. 85 severe asthma patients were divided into weed pollen group and HDM group according to relevant allergen. 20 healthy donors served as controls. Airway wall area, percentage wall area and luminal area at the trunk of the apical bronchus of the right upper lobe were quantified using HRCT and compared. The values of pulmonary function were assessed as well. There were differences between HDM group and weed pollen group in WA/BSA,WA% and FEF25-75% pred, and no significant difference in FEV1%pred, FEV1/FVC and LA/BSA. In weed pollen group, WA/BSA was observed to correlate with the duration of rhinitis, whereas in HDM group, WA/BSA and LA/BSA was observed to correlate with the duration of asthma. In weed pollen group, FEV1/FVC showed a weak but significant negative correlation with WA%, but in HDM group FEV1/FVC showed a significant positive correlation with WA% and a statistical negative correlation with LA/BSA. FEV1/FVC and FEF25-75% pred were higher and WA/BSA and LA/BSA were lower in healthy control group than asthma group. FEV1%pred and WA% was no significant difference between asthma patients and healthy subjects. There are differences between HDM mono-sensitized subjects and weed pollen mono-sensitized subjects, not only in airway wall thickness, but also small airway obstruction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Eco-distribution Mapping of Invasive Weed Limnocharis flava (L. Buchenau Using Geographical Information System: Implications for Containment and Integrated Weed Management for Ecosystem Conservation

    Directory of Open Access Journals (Sweden)

    P. C. Abhilash

    2008-03-01

    Full Text Available Exotic weed invasion has been identified as one of the serious environmental problem impacting the structure, composition and function of biological diversity. They are aggressive colonizers, which have flexible habitat requirement and ability to outcompete native species. The present paper describes the distribution and autecology of an exotic weed Limnocharis flava (L. Buchenau (an emergent aquatic weed of ‘Limnocharitaceae’ in Kumarakom Grama Panchayat, one of the well known tourist spot of South India famous for its vast stretches of paddy fields, wetlands and backwaters. The mapping of L. flava in the entire study area has been done using Geographical Information System (Arc-info 8.3 version. The growth and distribution pattern of L. flava were studied quantitatively. Data on distribution, abundance, biomass, ecological associations and root zone nutrient quality of water and sediment samples were collected from different sampling points of Kumarakom. The study reflected that nutrients, water depth and land use patterns were the major factors responsible for the growth and proliferation of this exotic weed. The strategies for controlling L. flava invasion are discussed in detail. If early steps are not taken to eradicate this weed, it will become a problematic weed in the same way as other noxious aquatic weeds like Salvinia molesta D. Mitch and Eichhornia crassipes (C. Martius Solms-Laub.

  14. Levels of nitrogen and iodosulfuron + mesosulfuron affecting the wheat competitive ability against weeds

    Directory of Open Access Journals (Sweden)

    Mahdi Zare

    2014-08-01

    Full Text Available The trial was a split plot experiment based on randomized complete block design (RCBD with four replications in Abadeh, Fars, Iran, during 2010-2011 growing seasons. The treatments were consisted of three levels of nitrogen (200, 300, and 400 kg ha-1 and four herbicide application levels (53, 68, 83, and 97 g ha-1. Interaction effects of N fertilizer×herbicide levels on number spike per m2, number of kernels spike-1, 1000-seed weight, harvest index, seed yield, number of wild oat, number of common mallow and common mallow dry matter weight were significant. The maximum seed yield was related to 300 kg ha-1 N fertilizer with 97 g ha-1 herbicide treatment (3,526 kg ha-1 and the minimum seed yield was belonged to 200 kg ha-1 N fertilizer with 53 g ha-1 herbicide treatment (2,242 kg ha-1. Number of spikes m-2 was the most important trait contributing to the grain yield in wheat. In conclusion, weed control was essential for efficient use of N fertilizer by the crop. Therefore, integration of N fertilization and herbicide is recommended for the region to increase wheat grain yield.

  15. Varietal Response of Chickpea (Cicer arietinum L.) Towards the Allelopathy of Different Weeds

    International Nuclear Information System (INIS)

    Rahamdad, K.; Ijaz, A.K.

    2015-01-01

    In a laboratory trial three chickpea varieties viz, Karak-I, Karak-III and Shenghar were tested against the phytotoxicity of five weed species: Parthenium hysterophorus L., Phragmites australis (Cav.) Trin., Datura alba L., Cyperus rotundus L. and Convolvulus arvensis L.in January 2013. The weed extracts were prepared at the rate of 120 g/L (w/v) after shade dry. The results indicated highly significant inhibitory effect of all the tested weed species on the chickpea varieties. The results also showed that the chickpea variety Karak-III was more susceptible to the phototoxicity of the tested weed extracts. Among the extract, C. arvensis proved much toxic in term of inhibition of germination by giving only 43.33% germination in comparison with control where 97.50% germination was recorded. On the other hand, the effect of P. australis extract was found a little stimulator by speeding the seed germination in all varieties and giving a low (2.21) mean germination time (MGT) value. From the current results it can be concluded that the infestation of C. arvensis can pollute the soil by accumulating toxic chemicals that leads to the germination failure and growth suppression in chickpea. Therefore, the prevention and removal of C. arvensis in the chickpea growing areas could be recommended. In addition, P. australis must be tested against chickpea weeds (chickpea varieties withstand against its phototoxicity), so that it can be popularized as bio herbicide in chickpea if it gave promising results in controlling chickpea weeds. (author)

  16. [Diversity and classification system of weed community in Harbin City, China].

    Science.gov (United States)

    Chen, Xiao-Shuang; Liang, Hong; Song, Kun; Da, Liang-Jun

    2014-08-01

    To analyze the causes of weed community diversity and their strategies of adaption to the high heterogeneity of urban habitats, weed communities in the central urban area of Harbin, China were studied, and a classification system was established for the weed communities. There were 175 weed species, belonging to 128 genera and 38 families. The heterogeneous urban habitats and species' temporal niche differentiation resulted in the highly diversified weed communities. The high proportions of mono-species dominance and annual species dominance communities were their response to the unstable urban habitats under human disturbances with high intensities and frequencies. A four-level classification system was established in terms of plant species and habitat conditions. Within this system, the identified 1763 weed communities could be categorized into two types of life form, 5 types of dormancy form, 22 community groups, and 119 dominance communities.

  17. BIOLOGICAL CONTROL OF WEEDS BY MEANS OF PLANT PATHOGENS

    OpenAIRE

    Marija Ravlić; Renata Baličević

    2014-01-01

    Biological control is the use of live beneficial organisms and products of their metabolism in the pests control. Plant pathogens can be used for weed control in three different ways: as classical, conservation and augmentative (inoculative and inundated) biological control. Inundated biological control involves the use of bioherbicides (mycoherbicides) or artificial breeding of pathogens and application in specific stages of crops and weeds. Biological control of weeds can be used where chem...

  18. Evaluation of the effectiveness of different herbicides against a new weed Japanese brome (Bromus japonicus Houtt. in wheat crop

    Directory of Open Access Journals (Sweden)

    Muhammad Asghar

    2017-06-01

    Full Text Available A field experiment was conducted to evaluate the efficacy of different post emergence herbicides for the control of monocot weed the Japanese broom (Bromus japonicus in wheat crop. Five herbicides viz., metribuzin, isoproturon, metribuzin plus isoproturon, Atlantis and sulfosulfuron were used at their recommended doses in RCBD with three replications. The weedy check was kept as control where no herbicide was sprayed. All the herbicides were applied as post-emergence after second irrigation at 60 days after sowing the crop. The lowest weed counts per m2 (0.583 and highest percent of weed mortality (99.07% were observed where metribuzin plus isoproturon was used. This was followed by Atlantis with 3.26 weeds per m2 with 95.14% mortality of weeds. However, significantly higher 1000 grain weight was noted with Atlantis (29.50 g and metribuzin plus isoproturon (28.58 g. The treatments did not differ significantly with respect to 1000 grain weight. All the herbicide helped to increase the yield from 16 to 22%, but did not differ significantly with respect to yield gain. The highest yield (3759.40 kg ha-1 was produced by Atlantis followed by sulfosulfuron (3757.20 kg ha-1 . On the basis of cost benefit ratio sulfosulfuron (34.95 proved to be the best followed by metribuzin (16.78. Therefore, sulfosulfuron and metribuzin are recommended for the control of Bromus weed in wheat crop.

  19. Interaction Effects of Planting Date and Weed Competition on Yield and Yield Components of Three white Bean Cultivars in Semirom

    Directory of Open Access Journals (Sweden)

    A. Yadavi

    2012-06-01

    Full Text Available Unsuitable planting and weed competition are the most important factors that greatly reduce the yield of bean. In order to study the effect of planting date on yield and yield components of three white bean cultivars in weed infest and weed free condition a factorial experiment with randomized complete block design and three replications was carried out at Semirom in 2009. The treatments were planting date (May10, May 25 and June 9 and white bean cultivars (Shekofa, Pak and Daneshkade and two levels of weed infestation (weedy and weed free. Results showed that planting date, weed competition and cultivars had significant effects on yield and yield components of white bean. The 30-day delay in planting date reduced the number of pods per plant, seeds per pod, 100 seed weight and biological yield of white bean cultivars, 22.5, 18, 20.1 and 22.5 percent respectively. Also weed competition, reduced the number of seeds per pod, 100 seed weight and biological yield respectively by 13.5, 5.7 and 27.1 percent. Result of planting date and weed competition interaction effects indicated that the weed competition decreased grain yield (53% in third planting date more than others and delay in planting date was companion with increasing weed density and dry weight in flowering stage of bean. Also Shekofa cultivar had highest grain yield (3379 kg/ha at the first planting date and weed free condition.

  20. Determining the potential of inedible weed biomass for bio-energy and ethanol production

    Directory of Open Access Journals (Sweden)

    Siripong Premjet

    2013-02-01

    Full Text Available Surveys of indigenous weeds in six provinces located in the low northern part of Thailand were undertaken to determine the potential of weed biomass for bio-energy and bio-ethanol. The results reveal that most of the weed samples had low moisture contents and high lower heating values (LHVs. The LHVs at the highest level, ranging from 17.7 to 18.9 Mg/kg, and at the second highest level, ranging from 16.4 to 17.6 Mg/kg, were obtained from 11 and 31 weed species, respectively. It was found that most of the collected weed samples contained high cellulose and low lignin contents. Additionally, an estimate of the theoretical ethanol yields based on the amount of cellulose and hemicellulose in each weed species indicated that a high ethanol yield resulted from weed biomasses with high cellulose and hemicellulose contents. Among the collected weed species, the highest level of ethanol yield, ranging from 478.9 to 548.5 L/ton (substrate, was achieved from 11 weed species. It was demonstrated that most of the collected weed species tested have the potential for thermal conversion and can be used as substrates for ethanol production.

  1. Broccoli/weed/soil discrimination by optical reflectance using neural networks

    Science.gov (United States)

    Hahn, Federico

    1995-04-01

    Broccoli is grown extensively in Scotland, and has become one of the main vegetables cropped, due to its high yields and profits. Broccoli, weed and soil samples from 6 different farms were collected and their spectra obtained and analyzed using discriminant analysis. High crop/weed/soil discrimination success rates were encountered in each farm, but the selected wavelengths varied in each farm due to differences in broccoli variety, weed species incidence and soil type. In order to use only three wavelengths, neural networks were introduced and high crop/weed/soil discrimination accuracies for each farm were achieved.

  2. Weeds as viable habitat for arthropod species in croplands of central Punjab

    International Nuclear Information System (INIS)

    Ruby, T.; Rana, S.A.; Rana, N.; Inayat, T.P.

    2011-01-01

    Weeds are considered a limiting factor of crop production. Simultaneously, these non-crop plants are a portion of the agricultural ecosystem and play an essential role as viable habitat for many organisms, including bio-control agents. Utilizing the quadrate method, sugarcane, fodder, wheat and mustard croplands were sampled for one year to determine the weed flora and arthropods living among it. Twenty weed species and eight major arthropod orders were found to be present. The majority of the weed plants were broad-leaved, while some were grass-like. A review of literature on Central Punjab weeds uncovered depicted a considerable change in the weed flora over few decades. This could be related to the intensive and extensive farming in the area, which has this increased over the few decades along with the construction of an extensive irrigation canal system. These alterations may have caused drastic changes in the soil structure and climate of the region. Most of the phytophagous arthropod species used weed plants as food. In turn, these were fed upon by a few zoophagous arthropod species that also utilized the weeds for shelter and oviposition. Thus, weeds have a specific role within the agro-ecosystem by supporting local biodiversity. (author)

  3. Opportunities and challenges for harvest weed seed control in global cropping systems.

    Science.gov (United States)

    Walsh, Michael J; Broster, John C; Schwartz-Lazaro, Lauren M; Norsworthy, Jason K; Davis, Adam S; Tidemann, Breanne D; Beckie, Hugh J; Lyon, Drew J; Soni, Neeta; Neve, Paul; Bagavathiannan, Muthukumar V

    2017-11-28

    The opportunity to target weed seeds during grain harvest was established many decades ago following the introduction of mechanical harvesting and the recognition of high weed-seed retention levels at crop maturity; however, this opportunity remained largely neglected until more recently. The introduction and adoption of harvest weed seed control (HWSC) systems in Australia has been in response to widespread occurrence of herbicide-resistant weed populations. With diminishing herbicide resources and the need to maintain highly productive reduced tillage and stubble-retention practices, growers began to develop systems that targeted weed seeds during crop harvest. Research and development efforts over the past two decades have established the efficacy of HWSC systems in Australian cropping systems, where widespread adoption is now occurring. With similarly dramatic herbicide resistance issues now present across many of the world's cropping regions, it is timely for HWSC systems to be considered for inclusion in weed-management programs in these areas. This review describes HWSC systems and establishing the potential for this approach to weed control in several cropping regions. As observed in Australia, the inclusion of HWSC systems can reduce weed populations substantially reducing the potential for weed adaptation and resistance evolution. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. Lawn Weed Control with Herbicides. Home and Garden Bulletin No. 123.

    Science.gov (United States)

    Agricultural Research Service (USDA), Washington, DC.

    Information and diagrams are given for identification and treatment of weed grasses and broadleaf weeds. Herbicides are suggested for use against each weed and instructions are given for proper application. Information is given for buying herbicides, and applying sprays and cleaning sprayers. (BB)

  5. Effect of different weed management techniques on growth ...

    African Journals Online (AJOL)

    The weed management techniques included slashing at 8-weekly intervals, mulching alone, glyphosate + slashing, glyphosate + mulching, glyphosate alone and a weed-free control. Glyphosate + mulching proved to have the greatest positive influence on plant height, plant girth, leaf area and number of leaves throughout ...

  6. Cover crop residue management for optimizing weed control

    NARCIS (Netherlands)

    Kruidhof, H.M.; Bastiaans, L.; Kropff, M.J.

    2009-01-01

    Although residue management seems a key factor in residue-mediated weed suppression, very few studies have systematically compared the influence of different residue management strategies on the establishment of crop and weed species. We evaluated the effect of several methods of pre-treatment and

  7. INVASIVE WEEDS IN BOGOR BOTANIC GARDENS, INDONESIA AND ITS IMPLICATION ON SURROUNDING LANDSCAPES

    Directory of Open Access Journals (Sweden)

    Edi Santosa

    2014-07-01

    Full Text Available Conservation areas with the objective for collection and exchange plant materials have been speculated as weed bank for surrounding areas. Objective of this study was to identify and characterize ruderal invasive weeds in the Bogor Botanic Gardens (BBG. Observations were conducted in all vak (collection blocks in the BBG in order to identify the weeds species, determine their invasiveness, dominance and distribution. Weeds associations with host plants were observed. Current weed control program and data of dead trees collection were analyzed in relevant to weed. Distribution of weeds outside BBG was observed by transects method following river and road directions. Results showed that there were seven invasive weeds, i.e., Cecropia adenopus (Cecropiaceae, Cissus nodosa Blume (Vitaceae, Cissus sicyoides Blume (Vitaceae, Dioscorea bulbifera L. (Dioscoreaceae, Ficus elastica Roxb. (Moraceae, Mikania micrantha H.B.K. (Asteraceae and Paraserianthes falcataria (L. Nielsen (Fabaceae. These seven weeds species invaded 41 out of 215 plant families in BBG. Six species of weeds, i.e., C. adenopus, C. nodosa Blume., C. sicyoides Blume., D. bulbifera L., M. micrantha H.B.K. and P. falcataria (L. Nielsen, were introduced as BBG collections for the first time while the F. elastica Roxb was considered as native. It is most likely that the weeds dispersal agents are the wind, birds, bats, visitors, and waters. All of these weeds existed in surrounding areas outside BBG. Given the detrimental impact of invasive weeds on the plant collection in BBG, it is necessary to develop long–term comprehensive control measures both inside and neighboring areas by involving other government authorities beyond BBG.

  8. Establishment and Early Growth of Willow at Different Levels of Weed Competition and Nitrogen Fertilization

    DEFF Research Database (Denmark)

    Edelfeldt, Stina; Lundkvist, Anneli; Forkman, Johannes

    2016-01-01

    To evaluate the effects of weed competition and nitrogen fertilization on the early growth performance of willow, cuttings of the clone Tora (Salix schwerinii x S. viminalis) were planted in buckets together with model weeds (spring barley or white mustard) sown 15, 26, and 30 days after willow...... gave higher willow biomass production in willow with weeds sown after 26 or 30 days. Type of model weed had no effect on willow performance. Weed biomass and maximum shoot height were higher in weeds planted without willows compared to the willow-weed mixtures. A high nitrogen level gave more weed...... biomass when planted without willows and in the willow-weed mixture with weeds sown after 15 days. We conclude that for the given high density of willow, competition from weeds emerging soon after willow planting had strong effect on early production. Furthermore, if there is a risk of weed infestation...

  9. Bio-herbicide effect of salt marsh tolerant Enterobacter sp. I-3 on weed seed germination and seedling growth

    International Nuclear Information System (INIS)

    Radhakrishan, R.; Lee, I.J.

    2017-01-01

    Weeds are major challenges in crop cultivation and cause yield loss. The bacteria based bio-herbicides are emerging against chemical herbicides. This study was aimed to explore the bio-herbicide effect of salt marsh tolerant Enterobacter sp. I-3 on various weed species. The efficacy of I-3 bacterial isolates against weed growth was compared with I-4-5 bacterial strain. The bacterial strains, I-3 and I-4-5 inhibited the seed germination of Cyperus microiria Maxim. Enterobacter sp. I-3 showed higher weed control activity than I-4-5. It was confirmed with growth reduction of C. microiria Maxim. The seed germination of Digitaria sanguinalis L. weed was accelerated during the interaction of I-4-5 and it was drastically declined by I-3 bacterial culture. However, Alopecurus aequalis Sobol. seeds treated with either I-3 or I-4-5 bacterial culture showed no significant germination inhibition. The results of this study suggested that salt marsh tolerant Enterobacter sp. I-3 can be applied as bacterial herbicides to control weeds in agricultural fields. (author)

  10. Influence of maize herbicides on weed seed bank diversity in a ...

    African Journals Online (AJOL)

    Influence of maize herbicides on weed seed bank diversity in a humid forest ... at 2.0 +2.0kg ai ha-1 was more effective in reducing weed seeds (seed bank) than the ... pre-emergence weed control program in diverse arable cropping systems ...

  11. Predicting field weed emergence with empirical models and soft computing techniques

    Science.gov (United States)

    Seedling emergence is the most important phenological process that influences the success of weed species; therefore, predicting weed emergence timing plays a critical role in scheduling weed management measures. Important efforts have been made in the attempt to develop models to predict seedling e...

  12. Control of perennial weeds by mechanical methods and anaerobic soil disinfection

    NARCIS (Netherlands)

    Huiting, H.F.; Bleeker, P.O.; Riemens, M.M.

    2011-01-01

    Perennial weeds are difficult to control and ask for a specific approach. During the most recent years it has even become a great challenge to control these weeds in conventional farming systems, although in comparison effective perennial weed control in organic farming systems remains more

  13. A century of progress in weed control in hardwood seedbeds

    Science.gov (United States)

    David B. South

    2009-01-01

    Weeds have existed in nurseries since before the time Bartram grew hardwoods during the 18th century. Hand weeding was the primary method of weed control during the first part of the 20th century. From 1931 to 1970, advances in chemistry increased the use of herbicides, and advances in engineering increased the reliance on machines for cultivation. Many managers now...

  14. Big Data for weed control and crop protection

    NARCIS (Netherlands)

    Evert, van F.K.; Fountas, S.; Jakovetic, D.; Crnojevic, V.; Travlos, I.; Kempenaar, C.

    2017-01-01

    Farmers have access to many data-intensive technologies to help them monitor and control weeds and pests. Data collection, data modelling and analysis, and data sharing have become core challenges in weed control and crop protection. We review the challenges and opportunities of Big Data in

  15. Adjustment of Weed Hoeing to Narrowly Spaced Cereals

    Directory of Open Access Journals (Sweden)

    Jannis Machleb

    2018-04-01

    Full Text Available Weed hoeing can be successfully performed in wide row crops, such as sugar beet, maize, soybean and wide spaced cereals. However, little experience is available for hoeing in narrow cereal row spaces below 200 mm. Yet, mechanical weed control can pose an alternative to herbicide applications by reducing the herbicide resistant populations present in the field. In this experiment, it was investigated whether hoeing is feasible in cereals with 150 and 125 mm row spacings. The trial was set up at two locations (Ihinger Hof and Kleinhohenheim in southwest Germany. Three different conventional hoeing sweeps, a goosefoot sweep, a no-till sweep and a down-cut side knife were adjusted to the small row widths, and hoeing was performed once with a tractor and a standard hoeing frame which was guided by a second human operator. The average grain yield, crop and weed biomass, and weed control efficacy of each treatment were recorded. The goosefoot and no-till sweep were tested at driving speeds of 4 and 6 km·h−1. The down-cut side knife was applied at 4 km·h−1. The results indicate that hoeing caused no yield decrease in comparison to a conventional herbicide application or manual weeding. The highest yield with a mechanical treatment was recorded for the no-till sweeps at both trial locations. Hoeing was performed successfully in narrowly spaced cereals of 150 and 125 mm, and the weed control efficacy of the mechanical treatments ranged from 50.9% at Kleinhohenheim to 89.1% at Ihinger Hof. Future experiments are going to focus on more distinct driving speeds ranging from 2 to 10 km·h−1 and performing more than one pass with the hoe. Additionally, combining the mechanical weeding tools with a camera-steered hoeing frame could increase accuracy, allow for higher working speeds and substitute the second human operator guiding the hoe.

  16. Floristic and phytosociology of weeds in pastures in Maranhão State, Northeast Brazil

    Directory of Open Access Journals (Sweden)

    Jaílson Penha Costa

    2016-06-01

    Full Text Available ABSTRACT Knowledge of weed floristic composition and phytosociology are key factors for improving weed management in pastures. Information on weed species that occur in pastures in Northeast Brazil, particularly in Maranhão State is very limited. It is, therefore, important, to search for information to help farmers to control weeds in livestock farming. This paper describes the weed flora diversity and community structure parameters, including density, frequency, abundance and importance value for each weed species found in five pastures of same age and management in Maranhão State, Northeast Brazil. The weed survey was carried out using a wooden frame (80 cm x 30 cm placed randomly on the soil surface 30 times in each pasture (n = 150. Weeds were pulled out, separated by species and counted. The weed flora was represented by 996 individuals, from nine families, 15 genera and 19 species. Weed density within pastures was of 44.3 plants m-2. The weed flora was dominated by species of the Cyperaceae and Poaceae families. The most important weed species based on Importance Value were Eragrostis ciliaris (IV = 32.97, Cyperus rotundus (IV = 31,95, Cyperus luzulae (IV = 27,50, Cyperus sphacelatus (IV = 27,42, Pycreus lanceolatus (IV = 27,33 Cyperus haspan (IV = 25,72 and Eleusine indica (IV = 23,49. Weed diversity, based on Shannon Diversity Index was very high (H' = 4.37 nats ind-1. Our results could lead to improved weed management in pastures in Maranhão State, Northeast Brazil.

  17. Yield loss prediction models based on early estimation of weed pressure

    DEFF Research Database (Denmark)

    Asif, Ali; Streibig, Jens Carl; Andreasen, Christian

    2013-01-01

    thresholds are more relevant for site-specific weed management, because weeds are unevenly distributed in fields. Precision of prediction of yield loss is influenced by various factors such as locations, yield potential at the site, variation in competitive ability of mix stands of weed species and emergence...

  18. Effect of Tillage in Day or Night and Application of Reduced Dosage of Imazethapyr and Trifluralin on Weed Control, Yield and Yield Components of Chickpea

    Directory of Open Access Journals (Sweden)

    A Abbasian

    2015-07-01

    Full Text Available This Experiment was arranged as a strip-plot on the base of a completely randomized block design with three replications to study the effect of tillage (whether in day or night or in day by light-proof cover and application of reduced dosage of imazethapyr and trifluralin on weed control, yield and yield components of chickpea. Main plots consisted of tillage methods and subplots consisted of trifluralin (at doses of 480, 960 and 1440 g ai /ha and imazethapyr (at doses of 50, 100 and 150 g ai /ha, plus weed free and weedy checks. Results showed weed biomass in day tillage, night tillage and in light-proof cover tillage were respectively 86, 127 and 148 g m-2. Therefore tillage at night or by light-proof cover in day time showed not enough efficiency in weed control. Weed biomass increased when application dose of herbicides decreased. Chickpea grain yield showed significant differences when different doses of herbicides applied. The minimum and the maximum seed yield were obtained respectively in weed free (by 208 g m-2 and weedy checks (by 123 g m-2. Reduced dosage of imazethapyr and trifluralin could control weeds good enough by no significant decrease in chickpea yield. Efficacy of imazethapyr to control weeds grown in chickpea was significantly better than that of trifluralin

  19. Herbicides as weed control agents: state of the art: I. Weed control research and safener technology: the path to modern agriculture.

    Science.gov (United States)

    Kraehmer, Hansjoerg; Laber, Bernd; Rosinger, Chris; Schulz, Arno

    2014-11-01

    The purpose of modern industrial herbicides is to control weeds. The species of weeds that plague crops today are a consequence of the historical past, being related to the history of the evolution of crops and farming practices. Chemical weed control began over a century ago with inorganic compounds and transitioned to the age of organic herbicides. Targeted herbicide research has created a steady stream of successful products. However, safeners have proven to be more difficult to find. Once found, the mode of action of the safener must be determined, partly to help in the discovery of further compounds within the same class. However, mounting regulatory and economic pressure has changed the industry completely, making it harder to find a successful herbicide. Herbicide resistance has also become a major problem, increasing the difficulty of controlling weeds. As a result, the development of new molecules has become a rare event today. © 2014 American Society of Plant Biologists. All Rights Reserved.

  20. Phytoremdiation Species And Their Modification Under By Weed Varying Climatic Condition A Changing Scenario

    Directory of Open Access Journals (Sweden)

    Anita Singh

    2015-08-01

    Full Text Available Abstract The major reasons for environmental contamination are population explosion increase in industrial and other urban activities. One of the consequent effect of these activities is heavy metal pollution. It is one of the serious issue to be discussed by the scientists and academicians that how to solve this problem to protect the environment. As heavy metals are non-biodegradable so they require effective cleanup technology. Most of the traditional methods such as excavation solidification and burial are very costly or they simply involve the isolation of the metals from contaminated sites. Among different technologies phytoremediation is best approach for removing metal contamination from environment. It involves plants to remove detoxify or immobilize metals from environment. Weed plants are found to be play very important role in metal remediation. They get affected by climatic variation which is also a consequent effect of environmental pollution. The physiology of plants as well as physiochemical properties of soil gets affected by varying climatic condition. Therefore the present review gives the information on metal remediation processes and how these process particularly phytoremediation by weed plants get affected by climatic changes.

  1. The Effect of Conservation Tillage and Cover Crop Residue on Beneficial Arthropods and Weed Seed Predation in Acorn Squash.

    Science.gov (United States)

    Quinn, N F; Brainard, D C; Szendrei, Z

    2016-12-01

    Conservation tillage combined with cover crops or mulching may enhance natural enemy activity in agroecosystems by reducing soil disturbance and increasing habitat structural complexity. In particular, weed seed predation can increase with vegetation cover and reduced tillage, indicating that mulches may improve the quality of the habitat for weed seed foraging. The purpose of this study was to quantify the effects of tillage and mulching for conservation biological control in cucurbit fields. The effects of mulch and reduced tillage on arthropods and rates of weed seed loss from arenas were examined in field trials on sandy soils in 2014 and 2015. Experimental factors included tillage and cover crop, each with two levels: strip-tillage or full-tillage, and cover crop mulch (rye residue) or no cover crop mulch (unmulched). Arthropod abundance on the crop foliage was not affected by tillage or cover crops. Contrary to expectations, epigeal natural enemies of insects and rates of weed seed removal either did not respond to treatments or were greater in full-tilled plots and plots without mulch. Our study demonstrates the potential importance of weed seed predators in reducing weed seedbanks in vegetable agroecosystems, and suggests that early-season tillage may not be detrimental to epigeal predator assemblages. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Effect of weed control treatments and cutting frequency on weed dry ...

    African Journals Online (AJOL)

    Two experiments were conducted during the rainy seasons of 2012 and 2013 at the Teaching and Research Farm of the Department of Crop Science, University of Nigeria, Nsukka, to evaluate the growth and leaf yield of Telfairia occidentials Hook F. as influenced by weed control treatments and cutting frequencies.

  3. Weed Growth Stage Estimator Using Deep Convolutional Neural Networks.

    Science.gov (United States)

    Teimouri, Nima; Dyrmann, Mads; Nielsen, Per Rydahl; Mathiassen, Solvejg Kopp; Somerville, Gayle J; Jørgensen, Rasmus Nyholm

    2018-05-16

    This study outlines a new method of automatically estimating weed species and growth stages (from cotyledon until eight leaves are visible) of in situ images covering 18 weed species or families. Images of weeds growing within a variety of crops were gathered across variable environmental conditions with regards to soil types, resolution and light settings. Then, 9649 of these images were used for training the computer, which automatically divided the weeds into nine growth classes. The performance of this proposed convolutional neural network approach was evaluated on a further set of 2516 images, which also varied in term of crop, soil type, image resolution and light conditions. The overall performance of this approach achieved a maximum accuracy of 78% for identifying Polygonum spp. and a minimum accuracy of 46% for blackgrass. In addition, it achieved an average 70% accuracy rate in estimating the number of leaves and 96% accuracy when accepting a deviation of two leaves. These results show that this new method of using deep convolutional neural networks has a relatively high ability to estimate early growth stages across a wide variety of weed species.

  4. Determination of critical period for weed control in the second crop ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-15

    Sep 15, 2009 ... maximize crop yield by eliminating weed competition and/ or minimizing ... fertilizer. When corn plants reached 80 cm in height, 170 kg N ha-1 was applied ... describing the effect of increasing duration of weed interference on corn yield ... corresponding value of length of weed-free period (d°C) and b and.

  5. PHYTOSOCIOLOGY OF WEEDS AFTER POTATO CULTIVATION (Solanum tuberosum L. IN THE VENEZUELAN ANDES:AN AGROECOLOGICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Pedro Manuel Villa

    2017-08-01

    Full Text Available Weeds represent one problem for potato cultivation in the Venezuelan Andes; however ecological studies to improve their management are limited. This study has aimed to carry out a phytosociological survey of weed community after potato cultivation in Mérida, Mérida state, Venezuela. The experiment was carried out under a completely randomized design with 20 plots (2x2 m. The weeds surveys were conducted at two month intervals, randomly selecting five plots per session during June 2006 and February 2007, to 60 days after cultivation (DDC, 120, 180, and 240 DDC. The phytosociological survey was performed involving identification and quantification of numbers of individuals the weeds in each plot. After were estimated of phytosociological parameters such as density, frequency, abundance to calculate the importance value index. A multivariate non-metric multidimensional scaling (NMDS was performed using species abundances; also was used the unweighted pair group method with arithmetic mean (UPGMA with presence absence data. Seventeen families, 32 genera and 35 species of weeds were identified, with the Asteraceae, Fabaceae and Poaceae families showed higher importance within the community. The most important species in the all stages were Pennisetum clandestinum, Paspalum decumbens, Desmodium adscendens, Aldama dentata, Borreria laevis, and Jaegeria hirta. Significant differences in phytosociological parameters were observed among weed species at each stage and among the different stages after potato cultivation.

  6. Effect of the foliar enrichment and herbicides on maize and associated weeds irrigated with drainage water

    Directory of Open Access Journals (Sweden)

    Roshdy M.H. Tagour

    2017-12-01

    Full Text Available A two-year field experiment was conducted during summer seasons of 2013 and 2014, which were irrigated by drainage water which belong to salinity class (C3S1 to C4S2, to study the effect of the foliar enrichment namely (Anti-stress and weed management treatments (some pre and post-emergence herbicides and two-hand hoeing on maize growth, yield, yield components and chemical composition of maize grains and associated weeds (Portulaca oleracea, Amaranthus retroflexus and Echinochloa colonum. The results illustrated that application of the foliar enrichment enhanced the dry weight of weeds and increased maize growth characters, yield and yield components and total crude protein and total oil percentage of grain maize, as compared with untreated treatment. All weed management treatments caused a significant reduction in total dry weight of weeds at 60 and 80 days after sowing in both seasons. Two-hand hoeing treatment exerted the highest decrease in total dry weight of weeds followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively at 60 and 80 days after sowing compared with other weed management treatments. While, the highest values of maize growth, yield, yield components and maize grains' content of protein and oil was obtained with two-hand hoeing followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively. While, two hands hoeing produced the maximum values of leaf area, ear length, the weight of kernels plant−1, but applying of metribuzin treatment gave the highest values of total oil percentage of grain maize when the foliar enrichment was used.

  7. effect of fluazitopbutyl and atrazine/metolachlor for weed control

    African Journals Online (AJOL)

    COCOYAM

    also gave the highest yield and monetary gain when compares with manual weeding. This technique will be ... be a “back yard” crop or “gap filler”. Survey reports in .... Critical period of weed interference intercropped with maize and cocoyam.

  8. Simulation of Soil Nitrogen Content Effect on Weed Seedling Emergence Pattern in Moldavian Balm (Dracocephalum moldavica L.

    Directory of Open Access Journals (Sweden)

    Afsaneh Moradian

    2016-06-01

    Full Text Available The soil nitrogen content with impact on weed seed dormancy breaking can change their seedling emergence pattern. A trial was carried out in 2014 to predict seedling emergence of Xanthium strumarium, Chenopodium album, Echinocloa cruss-galli,  Amaranthus retroflexus andConvolvulus arvensis,  and to evaluate the impact of soil nitrogen content (Control with 0.07% nitrogen, adding 50 and 100 kg N.ha-1 on seedling emergence pattern in Moldavian balm. The experimental design was randomized complete block design. Weed seedlings were counted and removed on a weekly basis throughout the season. The data were converted to percent of cumulative emergence and percentage of cumulative emergence values was compared with thermal time using Gompertz modified functions. The all species showed different emergence patterns and thermal time required for the onset of emergence. The results also showed that the emergence patterns of Chenopodium and Convolvulus  not affected by nitrogen treatments. However, soil nitrogen content significantly changed emergence patterns of A. retroflexus, E. cruss-galli and X. strumarium. According to our model, A. retroflexus, E. cruss-galli and X. strumarium emergence, respectively, started at 237, 96 and 63 TT with 50 kg additional nitrogen.ha-1, while the respective value in control were 340, 117 and 135, respectively. Due to influence of soil nitrogen on emergence pattern of A. retroflexus, E. cruss-galli and X. strumarium, soil nitrogen content should be considered as an important parameter in the modeling of these weed seedling emergence.

  9. Integration of Agronomic Practices with Herbicides for Sustainable Weed Management in Aerobic Rice

    Science.gov (United States)

    Anwar, M. P.; Juraimi, A. S.; Mohamed, M. T. M.; Uddin, M. K.; Samedani, B.; Puteh, A.; Man, Azmi

    2013-01-01

    Till now, herbicide seems to be a cost effective tool from an agronomic view point to control weeds. But long term efficacy and sustainability issues are the driving forces behind the reconsideration of herbicide dependent weed management strategy in rice. This demands reappearance of physical and cultural management options combined with judicious herbicide application in a more comprehensive and integrated way. Keeping those in mind, some agronomic tools along with different manual weeding and herbicides combinations were evaluated for their weed control efficacy in rice under aerobic soil conditions. Combination of competitive variety, higher seeding rate, and seed priming resulted in more competitive cropping system in favor of rice, which was reflected in lower weed pressure, higher weed control efficiency, and better yield. Most of the herbicides exhibited excellent weed control efficiency. Treatments comprising only herbicides required less cost involvement but produced higher net benefit. On the contrary, treatments comprising both herbicide and manual weeding required high cost involvement and thus produced lower net benefit. Therefore, adoption of competitive rice variety, higher seed rate, and seed priming along with spraying different early-postemergence herbicides in rotation at 10 days after seeding (DAS) followed by a manual weeding at 30 DAS may be recommended from sustainability view point. PMID:24223513

  10. Evaluation of pre and post-emergence herbicides for weed management in lentil (lens culinaris medik.)

    International Nuclear Information System (INIS)

    Ali, A.; Malik, S.R.; Munawwar, H.; Tahir, M.

    2014-01-01

    The weeds in lentil are one of the major constraints in obtaining maximum yield. The manual weed control is simply not feasible because it is time consuming and costly. The chemical weed control is the effective method of weed management.A field study was conducted to evaluate pre and post-emergence herbicides for weed control in lentil. The experiment comprised eight treatments including three herbicides, manual weeding and check (no weeding). The yield was higher in manual weeding but in herbicide treatments Isoproturon as pre-emergence at the rate 2kg/sup -1/ha produced statistically at par grain yield to that of manual weeding followed by Isoproturon after one month of planting at the rate 2kg ha. Both the treatments showed 193.9% and 109.2% yield increase, respectively, over the check. It indicates that Isoproturon at the rate 2 kg ha can be used pre or post-emergence in lentil fields to control the weeds without causing injury to lentil plants. (author)

  11. Impact of fertilizing pattern on the biodiversity of a weed community and wheat growth.

    Science.gov (United States)

    Tang, Leilei; Cheng, Chuanpeng; Wan, Kaiyuan; Li, Ruhai; Wang, Daozhong; Tao, Yong; Pan, Junfeng; Xie, Juan; Chen, Fang

    2014-01-01

    Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communities. To study the effects of different fertilizing patterns on the biodiversity of a farmland weed community and their adaptive mechanisms, indices of species diversity and responses of weed species and wheat were investigated in a 17-year field trial with a winter wheat-soybean rotation. This long term field trial includes six fertilizing treatments with different N, P and K application rates. The results indicated that wheat and the four prevalent weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) showed different responses to fertilizer treatment in terms of density, plant height, shoot biomass, and nutrient accumulations. Each individual weed population exhibited its own adaptive mechanisms, such as increased internode length for growth advantages and increased light interception. The PK treatment had higher density, shoot biomass, Shannon-Wiener and Pielou Indices of weed community than N plus P fertilizer treatments. The N1/2PK treatment showed the same weed species number as the PK treatment. It also showed higher Shannon-Wiener and Pielou Indices of the weed community, although it had a lower wheat yield than the NPK treatment. The negative effects of the N1/2PK treatment on wheat yield could be balanced by the simultaneous positive effects on weed communities, which are intermediate in terms of the effects on wheat and weeds.

  12. Smoking the Other: marijuana and counterhegemony in Weeds.

    Science.gov (United States)

    Lavoie, Dusty

    2011-01-01

    Subverting suburban modernity, the SHOWTIME television series Weeds invites its audiences to situate their opinions about marijuana amid spheres of bourgeois soccer-moms, class politics, turf wars, raw economics, violent milieux, and multiculti heterogeneity. I argue that Weeds encourages us to "smoke the Other"; that is, to hesitantly accept difference, in line with many drug circles' etiquette. The phrase "smoking the Other" is a critical alteration of bell hooks' (1992, Black looks: Race and representation. Boston: South End Press) conception of whites' ethnic "devouring" as "eating the Other," a rather rigid schematic itself problematized by Weeds' transgressive self-conscious playfulness with stereotyped ethnicities, loopy plotlines, and counterhegemonic dialogue. Cultural/political implications follow. Copyright © 2011 Informa Healthcare USA, Inc.

  13. Suicidal germination for parasitic weed control.

    Science.gov (United States)

    Zwanenburg, Binne; Mwakaboko, Alinanuswe S; Kannan, Chinnaswamy

    2016-11-01

    Parasitic weeds of the genera Striga and Orobanche spp. cause severe yield losses in agriculture, especially in developing countries and the Mediterranean. Seeds of these weeds germinate by a chemical signal exuded by the roots of host plants. The radicle thus produced attaches to the root of the host plant, which can then supply nutrients to the parasite. There is an urgent need to control these weeds to ensure better agricultural production. The naturally occurring chemical signals are strigolactones (SLs), e.g. strigol and orobanchol. One option to control these weeds involves the use of SLs as suicidal germination agents, where germination takes place in the absence of a host. Owing to the lack of nutrients, the germinated seeds will die. The structure of natural SLs is too complex to allow multigram synthesis. Therefore, SL analogues are developed for this purpose. Examples are GR24 and Nijmegen-1. In this paper, the SL analogues Nijmegen-1 and Nijmegen-1 Me were applied in the field as suicidal germination agents. Both SL analogues were formulated using an appropriate EC-approved emulsifier (polyoxyethylene sorbitol hexaoleate) and applied to tobacco (Nicotiana tabacum L.) fields infested by Orobanche ramosa L. (hemp broomrape), following a strict protocol. Four out of 12 trials showed a reduction in broomrape of ≥95%, two trials were negative, two showed a moderate result, one was unclear and in three cases there was no Orobanche problem in the year of the trials. The trial plots were ca 2000 m 2 ; half of that area was treated with stimulant emulsion, the other half was not treated. The optimal amount of stimulant was 6.25 g ha -1 . A preconditioning prior to the treatment was a prerequisite for a successful trial. In conclusion, the suicidal germination approach to reducing O. ramosa in tobacco fields using formulated SL analogues was successful. Two other options for weed control are discussed: deactivation of stimulants prior to action and

  14. On the development, environmental effects and human dimension of weed management strategies

    NARCIS (Netherlands)

    Riemens, M.M.

    2009-01-01

    On the development, environmental effects and human dimension of weed management strategies. On farm weed management is influenced by many factors. These factors comprise the development and availability of weed management tools, the environmental impact of these tools and the attitude and

  15. UAV low-altitude remote sensing for precision weed management

    Science.gov (United States)

    Precision weed management, an application of precision agriculture, accounts for within-field variability of weed infestation and herbicide damage. Unmanned aerial vehicles (UAVs) provide a unique platform for remote sensing of field crops. They are more efficient and flexible than manned agricultur...

  16. NUTRITIVE VALUE, In Vitro FERMENTATION AND SECONDARY METABOLITES OF WEEDS AND MAIZE STRAW USED FOR FEEDING DAIRY CATTLE

    Directory of Open Access Journals (Sweden)

    Raquel Martínez-Loperena

    2011-03-01

    Full Text Available In the highlands of Central Mexico a surplus of different forages is observed during the rainy season particularly weeds, which grow in maize fields. Weeds are widely used by farmers to feed dairy cattle. The objective of the present work was to determine the nutritive value of weeds, their content of secondary metabolites, and their effect on in vitro fermentation kinetics when included (at different levels of inclusion in a diet based on maize straw. The present study was carried out in two regions of the Toluca valley from August to October 2007. A split plot design was used to evaluate the variables associated with the nutritive value and a randomized design was employed to evaluate the content of secondary metabolites in the different weed species. Significant differences (P

  17. Economics of weed suppressive rice cultivars in flood- and furrow-irrigated systems

    Science.gov (United States)

    Weeds are a major constraint to rice production. In the U.S, weeds in rice are controlled primarily with synthetic herbicides. Intensive herbicide application in rice also has many potential drawbacks, resulting in environmental pollution, human health concerns, and development of weed resistance. B...

  18. Reduced herbicide doses in combination with allelopathic plant extracts suppress weeds in wheat

    International Nuclear Information System (INIS)

    Afridi, R.A.; Khan, M.A.

    2014-01-01

    Allelopathy is gaining popularity worldwide probably for decreasing the cost of production and environment friendly weed suppressing approach. Repeated field studies conducted during 2011-12 and 2012-13 at Agricutural Research Institute Tarnab, Peshawar, Pakistan where allelopathic water extracts of Oryza sativa, Parthenium hysterophorus, Phragmites australis and Datura alba along with reduced doses of phenoxaprop-p-ethyl and bromoxinil+MCPA were tested for controlling weeds in wheat. It was observed that weed density was encouragly suppressed whereas spike length (cm), number of spikelets spike-1 and 1000 grain weight (g) of the wheat were improved when the allelopathic plant water extracts were used in combination with lower doses of herbicides. Thus, allelochemicals provide weed suppressing option in wheat. However, more studies are required to fully explore the possibility of weed management and isolation of the chemicals involved in weed suppression for environment friendly weed management in wheat. Such studies may decrease the cost of crop production and total use of herbicides. (author)

  19. Peatland Fire Danger Rating According to Weeds Characteristic Under Jelutung (Dyera Polyphylla Plantation

    Directory of Open Access Journals (Sweden)

    Acep Akbar

    2016-04-01

    Full Text Available Besides to be a competitor plant, weeds could act as the potential fuel under plantation forest in peatland. Characteristic of weeds in relation to peat swamp forest fire danger was studied under jelutung  plantation in Central Kalimantan. The research was aimed at exploring the potency of weed to become one of the fire danger rating indicators. By using vegetation analyses method in sampling unit of weeds population, results showed that three plantation area have different dominance weed species. The weeds species that could be the indicator of height fire risk according to water content and percentage of weed mortality during the drought, height potency of greenhouse gas emmision, culm height, and chemical material content that easy burned in this study were Imperata cylindrica, Stenochlaena polustris, Cyclosorus aridus, and Nephrolepis exaltata. While, the presence of Glichenia linearis, Melastoma malabatracum, Ficus grossulariodes, Saurophus androginus, Spatoglathis plicata,Himenocalis littoralis, Leptaspis urcheolata, Cyperus rotundus, and Amaranthus spinosa were not indicated high fire risk.

  20. Root biomass in cereals, catch crops and weeds can be reliably estimated without considering aboveground biomass

    DEFF Research Database (Denmark)

    Hu, Teng; Sørensen, Peter; Wahlström, Ellen Margrethe

    2018-01-01

    and management factors may affect this allometric relationship making such estimates uncertain and biased. Therefore, we aimed to explore how root biomass for typical cereal crops, catch crops and weeds could most reliably be estimated. Published and unpublished data on aboveground and root biomass (corrected...

  1. An Autonomous Robotic System for Mapping Weeds in Fields

    DEFF Research Database (Denmark)

    Hansen, Karl Damkjær; Garcia Ruiz, Francisco Jose; Kazmi, Wajahat

    2013-01-01

    The ASETA project develops theory and methods for robotic agricultural systems. In ASETA, unmanned aircraft and unmanned ground vehicles are used to automate the task of identifying and removing weeds in sugar beet fields. The framework for a working automatic robotic weeding system is presented...

  2. Cruciferous weeds in oil seed rape – appearance and control

    Directory of Open Access Journals (Sweden)

    Klingenhagen, Günter

    2014-02-01

    Full Text Available Different cruciferous weeds were drilled in autumn 2011 and 2012 in a field near Münster. Beside common species like hedge mustard (Sisymbrium officinale Scop., shepherd`s purse (Capsella bursa-pastoris, pennycress (Thlaspiarvense, tall hedge mustard (Sisymbrium loeselii and flixweed (Descurainia sophia, we tried to establish weeds that are not common on arable land in Germany until now. These were: Yellow rocket (Barbarea vulgaris, hoary cress (Lepidium draba and Turkish rocket (Bunias orientalis. In autumn 2011 emergence of the sown weeds was poor. In the second year of experiment we got good emergence of the named weeds excluding hoary cress (Lepidium draba. In autumn 2011 and 2012 different herbicidecombinations were applied across the stripes. The best results were achieved with Colzor Trio (clomazone + dimethachlor + napropamid which was applied in pre-emergence state, a spray sequence Butisan Gold (metazachlor + quinmerac + dimethenamid-P applied in pre-emergence followed by Salsa (ethametsulfuronmethyl + Trend (adjuvant in post-emergence and Clearfield-Vantiga (metazachlor + quinmerac + imazamox + Dash (adjuvant, also applied in post-emergence state of the weeds.

  3. Skylarks trade size and energy content in weed seeds to maximize total ingested lipid biomass.

    Science.gov (United States)

    Gaba, Sabrina; Collas, Claire; Powolny, Thibaut; Bretagnolle, François; Bretagnolle, Vincent

    2014-10-01

    The trade-off between forage quality and quantity has been particularly studied in herbivore organisms, but much less for seed eating animals, in particular seed-eating birds which constitute the bulk of wintering passerines in European farmlands. The skylark is one of the commonest farmland birds in winter, mainly feeding on seeds. We focus on weed seeds for conservation and management purposes. Weed seeds form the bulk of the diet of skylarks during winter period, and although this is still a matter for discussion, weed seed predation by granivorous has been suggested as an alternative to herbicides used to regulate weed populations in arable crops. Our objectives were to identify whether weed seed traits govern foraging decisions of skylarks, and to characterize key seed traits with respect to size, which is related to searching and handling time, and lipid content, which is essential for migratory birds. We combined a single-offer experiment and a multiple-offer one to test for feeding preferences of the birds by estimating seed intake on weed seed species differing in their seed size and seed lipid content. Our results showed (1) a selective preference for smaller seeds above a threshold of seed size or seed size difference in the pair and, (2) a significant effect of seed lipid biomass suggesting a trade-off between foraging for smaller seeds and selecting seeds rich in lipids. Skylarks foraging decision thus seems to be mainly based on seed size, that is presumably a 'proxy' for weed seed energy content. However, there are clearly many possible combinations of morphological and physiological traits that must play crucial role in the plant-bird interaction such as toxic compound or seed coat. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Controlling weeds with fungi, bacteria and viruses: a review

    Science.gov (United States)

    Harding, Dylan P.; Raizada, Manish N.

    2015-01-01

    Weeds are a nuisance in a variety of land uses. The increasing prevalence of both herbicide resistant weeds and bans on cosmetic pesticide use has created a strong impetus to develop novel strategies for controlling weeds. The application of bacteria, fungi and viruses to achieving this goal has received increasingly great attention over the last three decades. Proposed benefits to this strategy include reduced environmental impact, increased target specificity, reduced development costs compared to conventional herbicides and the identification of novel herbicidal mechanisms. This review focuses on examples from North America. Among fungi, the prominent genera to receive attention as bioherbicide candidates include Colletotrichum, Phoma, and Sclerotinia. Among bacteria, Xanthomonas and Pseudomonas share this distinction. The available reports on the application of viruses to controlling weeds are also reviewed. Focus is given to the phytotoxic mechanisms associated with bioherbicide candidates. Achieving consistent suppression of weeds in field conditions is a common challenge to this control strategy, as the efficacy of a bioherbicide candidate is generally more sensitive to environmental variation than a conventional herbicide. Common themes and lessons emerging from the available literature in regard to this challenge are presented. Additionally, future directions for this crop protection strategy are suggested. PMID:26379687

  5. Trade off between costs and environmental effects of weed control on pavements

    NARCIS (Netherlands)

    Kempenaar, C.; Lotz, L.A.P.; Horst, van der C.L.M.; Beltman, W.H.J.; Leemans, K.J.M.; Bannink, A.D.

    2007-01-01

    An actor-participative project on sustainable weed control on pavements was started in 2000 in the Netherlands. The aim of the project was to develop a new concept of weed management that provides cost-effective and environmentally sound weed control. Early in 2002, practical guidelines were drawn

  6. Tolerance and selectivity of cereal species and cultivars to postemergence weed harrowing

    DEFF Research Database (Denmark)

    Rasmussen, Jesper; Nielsen, Helle Højland; Gundersen, Hanne

    2009-01-01

    POST weed harrowing and other cultivation methods to control weeds in early crop growth stages may result in crop damage due to low selectivity between crop and weeds. Crop tolerance to cultivation plays an important role but it has not been clearly defined and analyzed. We introduce a procedure...... for analyzing crop tolerance on the basis of digital image analysis. Crop tolerance is defined as the ability of the crop to avoid yield loss from cultivation in the absence of weeds, and it has two components: resistance and recovery. Resistance is the ability of the crop to resist soil covering and recovery...... abilities to suppress weeds. The order of species' tolerance to weed harrowing was triticale > wheat > barley > oat and the differences were mainly caused by different abilities to recover from soil covering. At 25% soil covering, grain yield loss in triticale was 0.5%, in wheat 2.5%, in barley 3...

  7. Spent coffee grounds as air-propelled abrasive grit for weed control

    Science.gov (United States)

    Spent coffee grounds (SCG) represent a significant food waste residue. Value-added uses for this material would be beneficial. Gritty agricultural residues, such as corncob grit, can be employed as abrasive air-propelled agents for organically-compatible postemergence shredding of weed seedlings sel...

  8. Species composition and density of weeds in a wheat crop depending on the soil tillage system in crop rotation

    Directory of Open Access Journals (Sweden)

    P. Yankov

    2015-03-01

    Full Text Available Abstract. The investigation was carried out in the trial field of Dobrudzha Agricultural Institute, General Toshevo on slightly leached chernozem soil type. For the purposes of this investigation, variants from a stationary field experiment initiated in 1987 and based on various soil tillage tools and operations were analyzed. The species composition and density of weeds were followed in a wheat crop grown after grain maize using the following soil tillage systems: plowing at 24 – 26 cm (for maize – disking at 10 – 12 cm (for wheat; cutting at 24 – 26 cm (for maize – cutting at 8 – 10 cm (for wheat; disking at 10 – 12 cm (for maize – disking at 10 – 12 cm (for wheat; no-tillage (for maize – no-tillage (for wheat.Weed infestation was read at the fourth rotation since the initiation of the trial. The observations were made in spring before treatment of the crop with herbicides. The soil tillage system had a significant effect on the species composition and density of weeds in the field with wheat grown after previous crop maize. The long-term alternation of plowing with disking in parallel with the usage of chemicals for weed control lead to lower weed infestation of the weed crop. The lower weed density after this soil tillage system was not related to changes in the species composition and the relative percent of the individual species in the total weed infestation. The long-term application in crop rotation of systems without turning of the soil layer and of minimal and no-tillage increased the amount of weeds. The reason is the greater variability of weed species which typically occur after shallow soil tillage.

  9. Using 7Be to document soil erosion on the weed plots

    International Nuclear Information System (INIS)

    Zhang Bo; Zhang Fengbao; Yang Mingyi

    2013-01-01

    Be tracing technology was applied to document soil erosion on the bare plot and weed plot, and compae soil erosion rate with the calculated rate. Results indicated that vegetation cover had obvious effect on the estimate of soil erosion rate on the weed plot using 7 Be measurement. Therefore, a factor of vegetation had been introduced into the Walling's model of converting 7 Be activity to soil erosion rate for estimating soil erosion rate on the weed slope surface. It was found that the soil erosion rates calculated by modified model were well close to the measured values on the weed plot, which illustrated that the modified model could be well used to estimate the rates of soil loss on the weed slope surface. These findings provide effective means for further study on the relationship between vegetation cover and soil erosion. (authors)

  10. Upper limit for context-based crop classification in robotic weeding applications

    DEFF Research Database (Denmark)

    Midtiby, Henrik Skov; Åstrand, Björn; Jørgensen, Ole

    2016-01-01

    Knowledge of the precise position of crop plants is a prerequisite for effective mechanical weed control in robotic weeding application such as in crops like sugar beets which are sensitive to mechanical stress. Visual detection and recognition of crop plants based on their shapes has been...... described many times in the literature. In this paper the potential of using knowledge about the crop seed pattern is investigated based on simulated output from a perception system. The reliability of position–based crop plant detection is shown to depend on the weed density (ρ, measured in weed plants per...... square metre) and the crop plant pattern position uncertainty (σx and σy, measured in metres along and perpendicular to the crop row, respectively). The recognition reliability can be described with the positive predictive value (PPV), which is limited by the seeding pattern uncertainty and the weed...

  11. Developing selection protocols for weed competitiveness in aerobic rice

    NARCIS (Netherlands)

    Zhao, D.L.; Atlin, G.N.; Bastiaans, L.; Spiertz, J.H.J.

    2006-01-01

    Aerobic rice production systems, wherein rice is dry-sown in non-puddled soil and grown as an upland crop, offer large water savings but are subject to severe weed infestation. Weed-competitive cultivars will be critical to the adoption of aerobic rice production by farmers. Breeding

  12. Weed biocontrol in the EU: from serendipity to strategy

    Science.gov (United States)

    Biological control of weeds is a globally-recognized approach to the management of the worst invasive plants in the world. Unfortunately, accidental introduction of agents account for most weed biocontrol in the EU, but do include a number of current or emerging successes. From the redistribution of...

  13. Effect of tillage on the efficacy of CGA362622 on weed control in maize

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-03

    Dec 3, 2008 ... time and resources managing weeds. Tillage alone or in combination with good cropping methods is ... help in managing herbicide resistance weeds and may also increase weed density as well as reduce crop yield .... This change in weed compo- sition agrees with Richley et al. (1977) indicating shift.

  14. Effect of conservation tillage and peat application on weed infestation on a clay soil

    Directory of Open Access Journals (Sweden)

    P. VANHALA

    2008-12-01

    Full Text Available Amendment of soil with peat is an attempt to avoid crop yield variation in the transition to conservation tillage, as it improves seedbed conditions and crop growth in drought-sensitive clay soils. Weed infestations were compared in 1999-2000 between the original and peat-amended clay (Typic Cryaquept, very fine, illitic or mixed under different autumn tillage systems in an oats-barley rotation. In a field experiment, sphagnum peat (H = 4 had been spread (0.02 m 3 m -2 on the soil surface in August 1995. Tillage treatments included mouldboard ploughing (to 20 cm and stubble cultivations of different working depths (8 or 15 cm and intensity (once or twice. Weed biomass and density were assessed by an area of 1 m 2 per field plot in August 1999-2000 and June 2000. The 1999 season was dry, but soil moisture conditions were more favourable in 2000. Peat application tended to increase the number of volunteer oats and Chenopodium album in 1999, while decreasing Galium spurium biomass. Ploughing significantly increased the abundance of Chenopodium album and Lamium purpureum in barley (Hordeum vulgare in 1999. Weed infestation was much lower in 2000, and tillage effect on Chenopodium album was minor in oats (Avena sativa. Growth of Lamium purpureum and Fumaria officinalis was stimulated in ploughed soils both years. Intensity and working depth of stubble cultivation had no significant effect on weeds.;

  15. WEED INTERFERENCE IN COTTON PLANTS GROWN WITH REDUCED SPACING IN THE SECOND HARVEST SEASON

    Directory of Open Access Journals (Sweden)

    MICHEL ALEX RAIMONDI

    2017-01-01

    Full Text Available Changes in row spacing may result in changes in crop and weed behavior and crop-weed competition. A study was performed to determine the periods of weed presence and weed control in cotton sown with 0.76 m spacing between planting rows. Cotton cultivar FM 993 was sown on 01/08/2010 with the aim of reaching a density of 190,000 seeds ha-1. Treatments with either weed presence or weed control during the first 0, 5, 10, 15, 22, 29, 36, 43, 50, 57, 64, 71, and 190 days of cultivation were established to determine the period prior to weed interference (PPI, total period of interference prevention (TPIP and critical period of weed control (CPWC. The weed species with high relative importance were Amaranthus retroflexus, Bidens pilosa, Eleusine indica, Digitaria horizontalis, Alternanthera tenella, and Commelina benghalensis. Considering a maximum yield loss of 5%, the PPI was established 11 days after cotton emergence (DAE, the TPWC at 46 DAE, and the CPWC between 11 and 46 DAE, for a total duration of 35 days. Considering a maximum acceptable yield loss equal to the standard deviation for the weed-free treatment, the PPI was established at 6 DAE, the TPWC at 55 DAE, and the CPWC between 6 and 55 DAE for a total duration of 49 days.

  16. Temperature and salinity affect the germination and growth of Silybum marianum Gaertn and Avena fatua

    International Nuclear Information System (INIS)

    Kashmir, S.; Khan, M. A.; Shad, A.

    2016-01-01

    Two troublesome weeds like Silybum marianum and Avena fatua were exposed to different levels of temperature and salinity. Laboratory based experimented were conducted in the Department of Weed Science, The University of Agriculture Peshawar during 2015. Sterilized seeds of S. marianum and A. fatua were placed in petri-dishes in a growth chamber. The temperature levels studied were 15, 25 and 40 degree C while the NaCl concentrations were 0, 100, 200, 300, 400, 500 and 600 mM. Data revealed that germination and growth related traits responded differently to different levels of temperature and salinity. Optimum temperature (25 degree C) resulted in higher germination and growth of both the weed species. While highest temperature used (40 degree C) or lower temperature (15 degree C) resulted in poor germination and growth of S. marianum and A. fatua. Salinity level up to 100 mM did not affect the seed germination of S. marianum and A. fatua. NaCl concentration above 100 mM significantly decreased germination and ceased the germination of both the weeds at 600 mM. Like germination, the growth related variables were also decreased at very low or very high temperature and higher concentrations of NaCl. It is concluded that temperature and NaCl can affect establishment, growth and seed production potential of S. marianum and A. fatua. (author)

  17. Effect of weed control methods on some soil properties of a newly ...

    African Journals Online (AJOL)

    Weed control constitutes a high percentage of the total field maintenance cost of newly planted cocoa. Soil samples were collected from an experiment that was designed to evaluate some weed control methods during cocoa establishment. The objective of the experiment was to assess the effect of the weed control ...

  18. 7 CFR 205.206 - Crop pest, weed, and disease management practice standard.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Crop pest, weed, and disease management practice... Requirements § 205.206 Crop pest, weed, and disease management practice standard. (a) The producer must use management practices to prevent crop pests, weeds, and diseases including but not limited to: (1) Crop...

  19. Effect Of Weed On Oil Palm Inflorenscence Production: Implication ...

    African Journals Online (AJOL)

    Weed consistently depressed the performance of oil palm and this depressive effect was attributed to aggressive growth resources, smothering of the oil palm and preventing the palm from proper ventilation and solar radiation. Weed interference on inflorescence production of oil palm was assessed with the view of ...

  20. Quantifying the effect of crop spatial arrangement on weed suppression using functional-structural plant modelling.

    Science.gov (United States)

    Evers, Jochem B; Bastiaans, Lammert

    2016-05-01

    Suppression of weed growth in a crop canopy can be enhanced by improving crop competitiveness. One way to achieve this is by modifying the crop planting pattern. In this study, we addressed the question to what extent a uniform planting pattern increases the ability of a crop to compete with weed plants for light compared to a random and a row planting pattern, and how this ability relates to crop and weed plant density as well as the relative time of emergence of the weed. To this end, we adopted the functional-structural plant modelling approach which allowed us to explicitly include the 3D spatial configuration of the crop-weed canopy and to simulate intra- and interspecific competition between individual plants for light. Based on results of simulated leaf area development, canopy photosynthesis and biomass growth of the crop, we conclude that differences between planting pattern were small, particularly if compared to the effects of relative time of emergence of the weed, weed density and crop density. Nevertheless, analysis of simulated weed biomass demonstrated that a uniform planting of the crop improved the weed-suppression ability of the crop canopy. Differences in weed suppressiveness between planting patterns were largest with weed emergence before crop emergence, when the suppressive effect of the crop was only marginal. With simultaneous emergence a uniform planting pattern was 8 and 15 % more competitive than a row and a random planting pattern, respectively. When weed emergence occurred after crop emergence, differences between crop planting patterns further decreased as crop canopy closure was reached early on regardless of planting pattern. We furthermore conclude that our modelling approach provides promising avenues to further explore crop-weed interactions and aid in the design of crop management strategies that aim at improving crop competitiveness with weeds.

  1. A special vegetation index for the weed detection in sensor based precision agriculture.

    Science.gov (United States)

    Langner, Hans-R; Böttger, Hartmut; Schmidt, Helmut

    2006-06-01

    Many technologies in precision agriculture (PA) require image analysis and image- processing with weed and background differentiations. The detection of weeds on mulched cropland is one important image-processing task for sensor based precision herbicide applications. The article introduces a special vegetation index, the Difference Index with Red Threshold (DIRT), for the weed detection on mulched croplands. Experimental investigations in weed detection on mulched areas point out that the DIRT performs better than the Normalized Difference Vegetation Index (NDVI). The result of the evaluation with four different decision criteria indicate, that the new DIRT gives the highest reliability in weed/background differentiation on mulched areas. While using the same spectral bands (infrared and red) as the NDVI, the new DIRT is more suitable for weed detection than the other vegetation indices and requires only a small amount of additional calculation power. The new vegetation index DIRT was tested on mulched areas during automatic ratings with a special weed camera system. The test results compare the new DIRT and three other decision criteria: the difference between infrared and red intensity (Diff), the soil-adjusted quotient between infrared and red intensity (Quotient) and the NDVI. The decision criteria were compared with the definition of a worse case decision quality parameter Q, suitable for mulched croplands. Although this new index DIRT needs further testing, the index seems to be a good decision criterion for the weed detection on mulched areas and should also be useful for other image processing applications in precision agriculture. The weed detection hardware and the PC program for the weed image processing were developed with funds from the German Federal Ministry of Education and Research (BMBF).

  2. Evaluation of the Effects of Integrated Management Weed Control on Corn Field by Using Reduced Dose of Foramsulfuron and Nicosulfuron Herbicides

    Directory of Open Access Journals (Sweden)

    M. Matinfar

    2011-09-01

    Full Text Available In order to evaluate the effects of integrated weed management on weed control by using reduced herbicide dose, a field experiment was conducted in 2010 in Qazvin. The experiment was conducted in randomized complete block design with 24 treatments and 4 replications. The treatments were: different planting patterns at three levels (single row, square double rows and zigzag double row  plantings and doses of  Nicosulfuron and Foramsulfuron application at four levels (1, 1/5, 2 and 2/5 liters per hectare, The results showed that among the different planting patterns, zigzag planting reduced weed populations and their dry weights significantly. Foramsulfuron herbicide could control weeds better than Nicosulfuron. Among the herbicide dosages, 2/5 litter dose per hectare highly reduced weed density its dry weight as compared to one litter dose.

  3. Illustrated weed flora of cotton crop of khairpur district, sindh, pakistan

    International Nuclear Information System (INIS)

    Memon, R.A.; Bhatti, G.R.

    2014-01-01

    A survey was carried out for the composition of weed flora of cotton crop of Khairpur district, Sindh, Pakistan. Thirty six weed species belonging to 16 families were noted. Poaceae was found to be most dominant family representing seven species followed by Asteraceae and Papilionaceae, each with five species. Botanical descriptions and illustrations/line drawings of all the recorded taxa were prepared in order to identify the weed species. (author)

  4. Biotechnology in weed control

    Science.gov (United States)

    Biotechnology can be used to enhance the management of weeds in several ways. Crops have been made resistant to herbicides by inserting transgenes that impart herbicide resistance into the plant genome. Glyphosate and glufosinate-resistant crops are commercialized in North America and crops made res...

  5. How to Identify and Control Water Weeds and Algae.

    Science.gov (United States)

    Applied Biochemists, Inc., Mequon, WI.

    Included in this guide to water management are general descriptions of algae, toxic algae, weed problems in lakes, ponds, and canals, and general discussions of mechanical, biological and chemical control methods. In addition, pictures, descriptions, and recommended control methods are given for algae, 6 types of floating weeds, 18 types of…

  6. Integrating management techniques to restore sites invaded by mile-a-minute weed, Persicaria perfoliata

    Science.gov (United States)

    Ellen C. Lake; Judith Hough-Goldstein; Vincent. D' Amico

    2014-01-01

    Efforts to suppress an invasive weed are often undertaken with the goal of facilitating the recovery of a diverse native plant community. In some cases, however, reduction in the abundance of the target weed results in an increase in other exotic weeds. Mile-a-minute weed (Persicaria perfoliata (L.) H. Gross (Polygonaceae)) is an annual vine from...

  7. Weeded Out? Gendered Responses to Failing Calculus.

    Science.gov (United States)

    Sanabria, Tanya; Penner, Andrew

    2017-06-01

    Although women graduate from college at higher rates than men, they remain underrepresented in science, technology, engineering, and mathematics (STEM) fields. This study examines whether women react to failing a STEM weed-out course by switching to a non-STEM major and graduating with a bachelor's degree in a non-STEM field. While competitive courses designed to weed out potential STEM majors are often invoked in discussions around why students exit the STEM pipeline, relatively little is known about how women and men react to failing these courses. We use detailed individual-level data from the National Educational Longitudinal Study (NELS) Postsecondary Transcript Study (PETS): 1988-2000 to show that women who failed an introductory calculus course are substantially less likely to earn a bachelor's degree in STEM. In doing so, we provide evidence that weed-out course failure might help us to better understand why women are less likely to earn degrees.

  8. Survey of Associations among Soil Properties and Climatic Factors on Weed Distribution in Wheat (Triticum aestivum L. in Kermanshah Province

    Directory of Open Access Journals (Sweden)

    Mozhgan veisi

    2016-11-01

    Full Text Available Introduction Kermanshah province, Iran, comprises an area, of 24640 km2 and is located between 33°37′-35°17′N and 45°20′-48°1′E. The average annual precipitation is 450 mm. Most of the fields surveyed in this study lie between 542 and 1554 m a.s.l. Among the factors decreasing the wheat yields, weeds have an important role. The results of some researches show that the weeds flora depends on climatic conditions, temperature and amount of rainfall in spring and in summer. Environmental factor splay a key role in the weed cover. These differences affected by climatic conditions, latitude and longitude. Multivariate statistical methods that have been addressed in this study area powerful tool to study the relationship between environmental factors and ecological weed community composition (Hassannejad & Pourhaydar Ghafarbi, 2013; Lososova et al., 2004. Correlation and regression of data floristic and environmental factors were used in the CCA (Canonical Correspondence Analysis technique (Legendre & Legendre, 1998. Materials and methods A survey was conducted to study the effects of soil and climatic factors on distribution of weeds in 85 irrigated wheat fields in 11 counties based on its area under irrigated wheat. An Experiment was conducted in Kermanshah province during 2011-2012. After choosing the field to be surveyed, the surveyor followed a “w”-designated set pattern to enumerate the weeds in each type of field. The pattern and number of 0.25 m2 quadrats varied according to the size of the fields. The field surveys were made during the wheat tillering to stem elongation stages. Frequency, density and mean density index of species in each county were calculated. After weed species were collected in the fields, we arranged the samples into the first matrix where weed species are represented by columns and fields of different districts by rows. Also, in the second matrix, environmental factors are represented by columns and fields

  9. Analysis of weed flora in conventional and organic potato production

    Directory of Open Access Journals (Sweden)

    Nikolić, Lj.

    2013-12-01

    Full Text Available Composition of weed flora is highly dynamic and depends upon great number of factors, of which cultural practices that are applied by humans in certain crops are the most important. One of the most frequently grown plants in the world and in our country is potato (Solanum tuberosum L., Solanaceae, due to its high biological and nutritive value. Therefore, in the paper was presented taxonomic analysis of weed flora in potato grown conventionally and according to the principles of organic agricultural production, with the intention to point out to eventual differences between present weeds. Of the total number of identified species, from phylum Equisetophyta and class Equisetopsida, in organic potato crop, was determined only one, Equisetum arvense. Of remaining 38 weeds from phylum Magnoliophyta., classified into two classes, Magnoliopsida and Liliopsida. On both of potato growing systems, 39 weed species were found, classified into 16 families and 32 genus. Of the total number, 31 species was identified in conventional potato crop, and only 23 species in potato crop grown according to organic principles, which is for about quarter less. Biological spectrum of weed flora in both potato growing systems is pronouncedly of terrophytic – geophytic type. In the spectrum of area types were recorded differences, i.e. in the conventional potato crop represented are only widely distributed species, while in the organic crop, beside species of wide distribution are also present elements of Pontic group.

  10. Robotic weed monitoring

    DEFF Research Database (Denmark)

    Bochtis, Dionysis; Sørensen, Claus Aage Grøn; Jørgensen, R N

    2011-01-01

    Abstract: In this paper, an integrated management system for the planning and activation of thefield monitoring task is presented. The architecture of the system is built around a mobile roboticunit. The internet based architecture of the system includes a station unit that works as a mobileon-fa...... of the weed monitoring operation.Key words: autonomous vehicles, farm management, mission planning, route planning,sampling....

  11. The benefits of using quantile regression for analysing the effect of weeds on organic winter wheat

    NARCIS (Netherlands)

    Casagrande, M.; Makowski, D.; Jeuffroy, M.H.; Valantin-Morison, M.; David, C.

    2010-01-01

    P>In organic farming, weeds are one of the threats that limit crop yield. An early prediction of weed effect on yield loss and the size of late weed populations could help farmers and advisors to improve weed management. Numerous studies predicting the effect of weeds on yield have already been

  12. Weed management in banana production: The use of Nelsonia ...

    African Journals Online (AJOL)

    During a survey of weeds in the Tiko banana plantations, the plant Nelsonia canescens (Lam.) Spreng was found to have invaded large areas of the plantation with no visible adverse effects on the banana crop. The effects of this Acanthaceae on banana yield parameters, snails' population and weed species diversity and ...

  13. economics of herbicide weed management in wheat in ethiopia ...

    African Journals Online (AJOL)

    ACSS

    Effective use of herbicides for the control of annual grass and broadleaf weeds in wheat (Triticum aestivum L.) was not a reality in Ethiopia, until in recent years. This study aimed at evaluating different post-emergence herbicides against annual grasses and broadleaf weeds in wheat for selection and incorporation into an ...

  14. Assessment of Changes in Weed Dry Weight and some Characteristics of Safflower (Carthamus tinctorius under Different Sources of Fertilizer and Intercropping

    Directory of Open Access Journals (Sweden)

    Saeid Heydarzadeh

    2017-04-01

    Full Text Available To study the effect of different organic and chemical fertilizers on weed biomass and some characteristics of safflower, a factorial experiment based on randomized complete block design with three replications was done at the Urmia University Reaearch Farm in 2013. Treatments consisted of growing of cover crops (red clover, grass pea, hairy, bitter vetch along with the safflower rows and two weed control treatments (with and without weed as a first factor and application of organic manure (cattle manure+biofertilizer and the different nitrogen and phosphuros fertilizer levels (100 % of recommended chemical fertilizer, 67 and 63 % of recommended N and P, 50 and 40 % of recommended N and P as second factor. Results showed that the biomass yield of broad and narrow leaf weeds affected by the combined treatments of cover crops and use of fertilizers. The biomass yield of broad and narrow leaf weeds were redused by 74.78, 82.22% under vetch cover crop when 50 and 40% of recommended N and P fertilizers were used, in comparison with sole culture of safflower and use of 100% of recommended chemical fertilizers. The maximum of seed yield (3431 kg.ha-1 and biological yield (8239 kg.ha-1 of safflower obtained from using 100% of recommended chemical fertilizers and without growing cover crops. Results, as a whole, showed that at higher levels of chemical fertilizers the competitive effects of weeds on safflower were higher than lower levels of fertilizers.

  15. Allelopathic Effect of Wheat and Barley Residues on Yield and Yield Components of Cowpea (Vigna sinensis L. and Weeds Control

    Directory of Open Access Journals (Sweden)

    M Shahbyki

    2018-02-01

    Full Text Available Introduction Weeds are a major constraint limiting crop yield in agricultural systems and in organic systems in particular. Although herbicides are efficient for weed control, continuous use has caused the development of resistance in weeds against several herbicides. Furthermore, herbicides also pollute the soil, water and aerial environments and herbicide residues in food have deteriorated food quality and enhanced the risk of diseases. Allelopathy is defined as the direct or indirect harmful or beneficial effects of one plant on another through the release of chemical compounds into the environment. Wheat (Triticum aestivum L. is known to be allelopathic against crops and weeds. The objective of this study was to investigate the allelopathic effect of wheat and barley residues on weeds control and cowpea yield. Materials and Methods An experiment was conducted as randomized complete block design with three replications at the research field (36° 25’E, 54° 58’N, 1349 m a.s.l. of Agricultural Faculty, Shahrood University of Technology in 2015. Treatments were included; weeding all season, no weeding, trifluralin according to the recommended dose (2 ton ha-1, foliar application of wheat straw extract (concentration of 50%, foliar application of wheat straw extract (concentration of 100%, the application of wheat residue mixed with the soil at a rate of 2 ton ha-1, the application of wheat residue mixed with the soil at a rate of 4 ton ha-1, the application of wheat residue mixed with the soil at a rate of 8 ton ha-1, foliar application of barley straw extract (concentration of 50%, foliar application of barley straw extract (concentration of 100%. Statistical analysis of data was performed with MSTAT-C software and means were compared with LSD test at the 5% level of probability. Results and Discussion The results showed that the effect of treatments was significant (P 0.01 on weed density and dry weight. Soil incorporation with wheat

  16. Distribution Map and Community Characteristics of Weeds in Barley Fields of Ardabil Province

    OpenAIRE

    B. Soheili; M. Minbashi; D. Hasanpanah; N. Razmi

    2013-01-01

    Surveying weeds of irrigated barley fields is one of the most important practices in weed management. Based on cultivated areas irrigated barley in all counties of Ardabil province during six years (2000-2005), 46 sample barley fields were selected and weed species were counted in each sampling point and population indices were calculated with Thomas method. By using specific furmula the density, frequency and uniformity of each weed species in fields were calculated. In each field longitude,...

  17. Soil microbes and successful invasions of an exotic weed Eupatorium adenophorum

    International Nuclear Information System (INIS)

    Zhou, P.; Tang, T.; Zhao, P.; Chen, J.

    2016-01-01

    The effects of soil microbes collected from the two invasive species Eupatorium adenophorum and E. odoratum and the two native species E. japonicum and E. chinense on the growth and biomass of E. adenophorum was examined to explore a possible link between soil microbes and successful invasions of the weed species E. adenophorum. In most cases, plant height, stem diameter, root number and root length were significantly enhanced when E. adenophorum was grown in sterilized soils compared with those when one was grown in non-sterilized soils collected from the rhizosphere of E. adenophorum, E. japonicum and E. chinense. In contrast, the growth and biomass of E. adenophorum were apparently inhibited when grown in soils collected from the rhizosphere of E. odoratum. Plant height, stem diameter, leaf area per plant and root length of E. adenophorum was greater when it was grown in soils collected from the rhizosphere of E. adenophorum compared with those when it was grown in soils collected from the rhizosphere of E. odoratum, but the enhancement considerably greater when it was grown in soils collected from the rhizosphere of E. japonicum and E. chinense compared with those when it was grown in soils collected from the rhizosphere of E. adenophorum. In addition, the biomass allocation of E. adenophorum was not significantly affected by soil microbes and soil sources. These Results suggest that although the competitive advantage of the invasive weed E. adenophorum is not achieved solely by soil microbes, successful invasions of E. adenophorum may result partly from its release from the harmful soil microbes in its native range and the positive feedbacks of soil microbes from itself and the native species in its invading range. (author)

  18. Weed occurrence in Finnish coastal regions: a survey of organically cropped spring cereals

    Directory of Open Access Journals (Sweden)

    P. RIESINGER

    2008-12-01

    Full Text Available Weed communities of organically cropped spring cereal stands in the southern and the northwestern coastal regions of Finland (= south and northwest, respectively were compared with respect to number of species, frequency of occurrence, density and dry weight. Regional specialization of agricultural production along with differences in climate and soil properties were expected to generate differences in weed communities between south and northwest. Total and average numbers of species were higher in the south than in the northwest (33 vs. 26 and 15.6 vs. 10.0, respectively. Some rare species (e.g. Papaver dubium were found in the south. Fumaria officinalis and Lamium spp. were found only in the south. The densities and dry weights of Lapsana communis, Myosotis arvensis, Polygonum aviculare, Tripleurospermum inodorum and Vicia spp. were higher in the south, while the densities and dry weights of Elymus repens, Persicaria spp. and Spergula arvensis were higher in the northwest. Total density of weeds did not differ between south and northwest (average = 565 vs. 570 shoots m-2, respectively. Total dry weight of weeds was higher in the northwest compared with the south (average = 1594 vs. 697 kg ha-1, respectively, mainly due to the high dry weight of E. repens. The only variable that was dependent on the duration of organic farming was weed density in the south. The abundance of nitrophilous in relation to non-nitrophilous weed species was higher while the abundance of perennial ruderal and grassland weed species was lower compared with previous weed surveys. This can be regarded as the result of increasing cropping intensity on organic farms in Finland. Different weed communities call for the application of specific target-oriented weed management in the respective coastal regions.;

  19. Water hyacinth : the suitable aquatic weed for radioactive nuclide absorption in water

    International Nuclear Information System (INIS)

    Chalermsuk, Somporn; Jungpattanawadee, Komgrid; Tongrong, Thanachai

    2003-06-01

    The experiment was set up to determine the quantities of radioactive nuclides which were absorbed by aquatic weeds in Khon Kaen Province. The best aquatic weed would be used to be sampled for study of radioactive nuclide quantities in natural water resources. Seven kinds of aquatic weeds in the same site were corrected and pretreated by ovening to be ash at 450 οC. Gamma-ray spectra of the samples were detected and analyzed for comparing the quantities of radioactive nuclides. Gamma-ray spectrometry with a HPGe detector was set up to detect radioactive nuclides and their quantities in ashes of aquatic weeds. According to this study, water hyacinth, from seven aquatic weeds, had the most quantities of radioactive nuclides. The water hyacinth with 30 cm leaves in length can absorb the most quantities of radioactive nuclides

  20. Efficacy of selected herbicide formulations on sugarcane field weeds ...

    African Journals Online (AJOL)

    In continuation for the search of appropriate weed control strategy for sugarcane field weeds at the Unilorin Sugar Research Institute (USRI), Ilorin located at 8o 030' N; 4o 32' E , Nigeria. Field trials were laid out in a randomized complete block design during 2012 and 2013 growing seasons to evaluate four herbicide ...

  1. [Effects of different fertilization regimes on weed communities in wheat fields under rice-wheat cropping system].

    Science.gov (United States)

    Yuan, Fang; Li, Yong; Li, Fen-hua; Sun, Guo-jun; Han, Min; Zhang, Hai-yan; Ji, Zhong; Wu, Chen-yu

    2016-01-01

    To reveal the effects of different fertilization regimes on weed communities in wheat fields under a rice-wheat rotation system, a survey was conducted before wheat harvest in 2014 after a 4-year long-term recurrent fertilization scheme. Weed species types, density, height and diversity index under different fertilization and straw-returning schemes in wheat fields were studied and complemented with a canonical correspondence analysis on weed community distribution and soil nutrient factors. Twenty weed species were recorded among 36 wheat fields belonging to 19 genera and 11 families. Beckmannia syzigachne, Hemistepta lyrata, Malachium aquaticum and Cnidium monnieri were widely distributed throughout the sampled area. Long-term fertilization appeared to reduce weed species richness and density, particularly for broadleaf weeds, but increased weed height. Diversity and evenness indices of weed communities were lower and dominance indices were higher in fields where chemical fertilizers were applied alone or combined with organic fertilizers, especially, where organic-inorganic compound fertilizer was used, in which it readily caused the outbreak of a dominant species and severe damage. Conversely, diversity and evenness indices of weed communities were higher and dominance indices were lower when the straw was returned to the field combined with chemical or organic fertilizers, in which weed community structures were complex and stable with lower weed density. Under these conditions weeds only caused slight reduction of wheat growth.

  2. Weed seed spread and its prevention: The role of roadside wash down.

    Science.gov (United States)

    Bajwa, Ali Ahsan; Nguyen, Thi; Navie, Sheldon; O'Donnell, Chris; Adkins, Steve

    2018-02-15

    Vehicles are one of the major vectors of long-distance weed seed spread. Viable seed removed from vehicles at roadside wash down facilities was studied at five locations in central Queensland, Australia over a 3-year period. Seed from 145 plant species, belonging to 34 different families, were identified in the sludge samples obtained from the wet particulate matter collection pit of the wash down facilities. Most of the species were annual forbs (50%) with small or very small seed size (weed was observed in these samples. More parthenium weed seed were found in the Rolleston facility and in the spring, but its seed was present in all facilities and in all seasons. The average number of viable seed found within every ton of dry particulate matter removed from vehicles was ca. 68,000. Thus, a typical wash down facility was removing up to ca. 335,000 viable seed from vehicles per week, of which ca. 6700 were parthenium weed seed. Furthermore, 61% of these seed (ca. 200,000) were from introduced species, and about half of these (35% of total) were from species considered to be weeds. Therefore, the roadside wash down facilities found throughout Queensland can remove a substantial amount of viable weed seed from vehicles, including the invasive parthenium weed, and the use of such facilities should be strongly encouraged. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Comparative impact of genetically modified and non modified maize (Zea mays L.) on succeeding crop and associated weed.

    Science.gov (United States)

    Ibrahim, Muhammad; Ahmed, Naseer; Ullah, Faizan; Shinwari, Zabta Khan; Bano, Asghari

    2016-04-01

    This research work documents the comparative impact of genetically modified (GM) (insect resistance) and non modified maize (Zea mays L.) on growth and germination of succeeding crop wheat (Triticum aestivum L.) and associated weed (Avena fatua L.). The aqueous extracts of both the GM and non-GM maize exhibited higher phenolic content than that of methanolic extracts. Germination percentage and germination index of wheat was significantly decreased by GM methanolic extract (10%) as well as that of non-GM maize at 3% aqueous extract. Similarly germination percentage of weed (Avena fatua L.) was significantly reduced by application of 3% and 5% methanolic GM extracts. All extracts of GM maize showed non-significant effect on the number of roots, root length and shoot length per plant but 5% and 10% methanolic extracts of non-GM maize significantly increased the number of roots per plant of wheat seedling. Similarly, 10% methanolic extract of GM maize significantly increased the number of roots per plant of weed seedling. Methanolic extracts of GM and non-GM maize (3% and 5%) significantly decreased the protease activity in wheat as compared to untreated control. © The Author(s) 2013.

  4. Controlling herbicide-susceptible, -tolerant and -resistant weeds with microbial bioherbicides

    Science.gov (United States)

    The management of weeds is a necessary but expensive challenge. Public concerns of health, safety, and sustainability have increased interest in reducing the use of synthetic chemicals for weed control. Alternatives to chemical herbicides, such as bioherbicides, may offer an alternative to herbicide...

  5. Weed infestation of winter wheat (Triticum aestivum L. under the conditions of application of some retardants

    Directory of Open Access Journals (Sweden)

    Elżbieta Harasim

    2013-07-01

    Full Text Available A field study was conducted in the period 2004–2007 on grey-brown podzolic soil (sandy. This study analysed the relationship between the use of stem shortening in cereals by means of retardants with the following active substances: chlormequat chloride (Antywylegacz Płynny 675 SL, trinexapac-ethyl (Moddus 250 EC, chlormequat chloride + ethephon (Cecefon 465 SL, and weed infestation. The retardants were applied at the 1st node stage (BBCH 31 – Antywylegacz Płynny 675 SL and the 2nd node stage of winter wheat (BBCH 32 – Moddus 250 EC and Cecefon 465 SL, together with the adjuvant Atpolan 80 EC (75% of SN 200 mineral oil or without the adjuvant. Winter wheat, cv. 'Muza', was grown after vetch grown for seed. The whole experiment was sprayed with the herbicides Apyros 75 WG and Starane 250 EC at the full tillering stage (BBCH 29–30. Plots where no growth regulators were used were the control treatment. Weed density and biomass showed great variation between years. In the winter wheat crop, Veronica persica, Viola arvensis, Veronica arvensis, Capsella bursa-pastoris,and Chenopodium album dominated in the dicotyledonous class, whereas Apera spica-venti, Echinochloa crus-galli,and Elymus repens were predominant among monocotyledonous plants. The level of weed infestation of the winter wheat crop, as measured by the number and air-dry weight of weeds, was significantly differentiated by years and retardants used as well as by interactions of these factors. The adjuvant Atpolan 80 EC did not have a significant effect on the above-mentioned weed infestation parameters. .

  6. Narrow rows reduce biomass and seed production of weeds and increase maize yield

    NARCIS (Netherlands)

    Mashingaidze, A.B.; Werf, van der W.; Lotz, L.A.P.; Chipomho, J.; Kropff, M.J.

    2009-01-01

    Smallholder farmers in southern African countries rely primarily on cultural control and hoe weeding to combat weeds, but often times, they are unable to keep up with the weeding requirements of the crop because of its laboriousness, causing them to incur major yield losses. Optimisation of crop

  7. The Art and the Science of Cultivation for Weed Control in Organic Peanut

    Science.gov (United States)

    Cultural weed control is the basis on which an integrated system of weed management in organic peanut is based. The cultural practices evaluated for weed control were row patterns and seeding rates, integrated with cultivation intensity. Results showed that peanut seeded in wide rows (two rows, 91...

  8. Weed Control Efficiency of wild Safflower (Carthamus oxyacanthus M. Bieb in Replacement Series Technique of Barley (Hordeum vulgare L. and Common Vetch (Vicia sativa L.

    Directory of Open Access Journals (Sweden)

    abdolreza ahmadi

    2017-08-01

    significant 1% and 5%. Results and discussion There was significant difference between minimum and maximum dry weight of weeds, the results showed that barley have important role in weed control wild safflower. Therefore, weed control efficiency in 15 plant in m2 was higher than two 10 and 20 plant in m2. The lowest WCE (161.27% was found at 15-35-65 treatment, but, the highest WCE (51.99 was obtained from 15-65-35 (Wild safflower-common vetch-barley treatment. Computes showed that WCE, in 15 plants of wild safflower/m2, was more than 10 and 20 p/m2. The reduction in weed population and biomass in intercropping systems with barley may be attributed to shading effect and competition stress created by the canopy. Thus, result showed that reduction rate of common vetch in intercropping, with bearing compatibility power to weeds reduced LER. CR for common vetch intercropping component in comparison with barley in total treatments was>1. The highest CR, for vetch obtained from treatment 45-55-control (2.64 and for barley from seed ratio 65-35-control (1.83. Conclusion The results in this study showed various seed rate had noticeable effect on forage yield, LER and weed control. In this experiment changing seed rate in two tested plants (barly- commen vetch changed the number and weed species, as a result noticeable changing was created in their competitive power. Result showed that seed rate (35% barley-65% common vetch was better than other treatment, not only in use efficiency of environment, but also it had more dry forage yield. Also, former seed rate had effective role in decreasing the weed biomass. This important result was related to reduced light penetrate at the bottom of cover crop and probably lack of competition in access to environmental resources was also affected. So using this seed density for mentioned area is recommended for reducing weed competition and improving the quality and quantity of dry forage. Acknowledgments The authors gratefully acknowledge the

  9. Distribution Map and Community Characteristics of Weeds in Barley Fields of Ardabil Province

    Directory of Open Access Journals (Sweden)

    B. Soheili

    2013-06-01

    Full Text Available Surveying weeds of irrigated barley fields is one of the most important practices in weed management. Based on cultivated areas irrigated barley in all counties of Ardabil province during six years (2000-2005, 46 sample barley fields were selected and weed species were counted in each sampling point and population indices were calculated with Thomas method. By using specific furmula the density, frequency and uniformity of each weed species in fields were calculated. In each field longitude, latitude and altitude were recorded by using GPS. These data were used for producing weed maps using GIS. Results showed that Galium tricurnatum, Fumaria vaillantiand Raphanus raphanistrum were dominante broadleaf species in irrigated barley fields of Ardabil province. The dominant grassy weed species in these fields were Avena fatua and Secale cereal. Convolvulus arvensis and Cirsium arvense were the most important troublesome plants prior to harvesting in irrigated barley fields of this province.

  10. Weed composition in relation to site in re-established pine ...

    African Journals Online (AJOL)

    A survey of weed species distribution patterns and abundance in clearfelled pine compartments in the Mpumalanga escarpment region was undertaken to determine the relationship between weed species and cover abundance in relation to environmental and compartmental factors. In total 359 transects were sampled ...

  11. Crop/weed discrimination using near-infrared reflectance spectroscopy (NIRS)

    Science.gov (United States)

    Zhang, Yun; He, Yong

    2006-09-01

    The traditional uniform herbicide application often results in an over chemical residues on soil, crop plants and agriculture produce, which have imperiled the environment and food security. Near-infrared reflectance spectroscopy (NIRS) offers a promising means for weed detection and site-specific herbicide application. In laboratory, a total of 90 samples (30 for each species) of the detached leaves of two weeds, i.e., threeseeded mercury (Acalypha australis L.) and fourleafed duckweed (Marsilea quadrfolia L.), and one crop soybean (Glycine max) was investigated for NIRS on 325- 1075 nm using a field spectroradiometer. 20 absorbance samples of each species after pretreatment were exported and the lacked Y variables were assigned independent values for partial least squares (PLS) analysis. During the combined principle component analysis (PCA) on 400-1000 nm, the PC1 and PC2 could together explain over 91% of the total variance and detect the three plant species with 98.3% accuracy. The full-cross validation results of PLS, i.e., standard error of prediction (SEP) 0.247, correlation coefficient (r) 0.954 and root mean square error of prediction (RMSEP) 0.245, indicated an optimum model for weed identification. By predicting the remaining 10 samples of each species in the PLS model, the results with deviation presented a 100% crop/weed detection rate. Thus, it could be concluded that PLS was an available alternative of for qualitative weed discrimination on NTRS.

  12. Impact of the timing and duration of weed control on the establishment of a rubber tree plantation.

    Science.gov (United States)

    Guzzo, Caio D; Carvalho, Leonardo B de; Giancotti, Paulo R F; Alves, Pedro L C A; Gonçalves, Elaine C P; Martins, José V F

    2014-03-01

    Rubber tree production is reduced by weeds that compete for environmental resources; therefore, the timing and duration of weed control influences weed interference. The objectives of this study were to evaluate the growth of rubber tree (Hevea brasiliensis) plants, to determine the critical period for weed control, and to evaluate the growth recovery of rubber trees that coexisted with weeds for different periods of time after planting. Two groups of treatments were established under field conditions in the first year of the investigation: one group contained crescent periods of weed infestation, while the other contained crescent periods of weed control, also including a weed-free check and a total weedy check. In the second year of the investigation, the weeds were totally controlled. Urochloa decumbens was the dominant weed (over 90% groundcover). Crop growth was greatly reduced due to the weed interference. Plant height decreased more rapidly than did any other characteristic. Plant height, leaf dry mass, and leaf area decreased by 99%, 97% and 96%, respectively, and were the most reduced characteristics. Plant height also recovered more rapidly than did any characteristic when the period of weed control was lengthened. However, stem dry mass increased by 750%, making it the most recovered characteristic. The critical period for weed control was between 4 and 9½ months after planting in the first year; however, the rubber trees showed an expressive growth recovery when the weeds were controlled throughout the second year.

  13. Using WEED to simulate the global wetland distribution in a ESM

    Science.gov (United States)

    Stacke, Tobias; Hagemann, Stefan

    2016-04-01

    Lakes and wetlands are an important land surface feature. In terms of hydrology, they regulate river discharge, mitigate flood events and constitute a significant surface water storage. Considering physical processes, they link the surface water and energy balances by altering the separation of incoming energy into sensible and latent heat fluxes. Finally, they impact biogeochemical processes and may act as carbon sinks or sources. Most global hydrology and climate models regard wetland extent and properties as constant in time. However, to study interactions between wetlands and different states of climate, it is necessary to implement surface water bodies (thereafter referred to as wetlands) with dynamical behavior into these models. Besides an improved representation of geophysical feedbacks between wetlands, land surface and atmosphere, a dynamical wetland scheme could also provide estimates of soil wetness as input for biogeochemical models, which are used to compute methane production in wetlands. Recently, a model for the representation of wetland extent dynamics (WEED) was developed as part of the hydrology model (MPI-HM) of the Max-Planck-Institute for Meteorology (MPI-M). The WEED scheme computes wetland extent in agreement with the range of observations for the high northern latitudes. It simulates a realistic seasonal cycle which shows sensitivity to northern snow-melt as well as rainy seasons in the tropics. Furthermore, flood peaks in river discharge are mitigated. However, the WEED scheme overestimates wetland extent in the Tropics which might be related to the MPI-HM's simplified potential evapotranspiration computation. In order to overcome this limitation, the WEED scheme is implemented into the MPI-M's land surface model JSBACH. Thus, not only its effect on water fluxes can be investigated but also its impact on the energy cycle, which is not included in the MPI-HM. Furthermore, it will be possible to analyze the physical effects of wetlands in a

  14. Vermicomposting and anaerobic digestion – viable alternative options for terrestrial weed management – A review

    Directory of Open Access Journals (Sweden)

    Biswanath Saha

    2018-03-01

    Full Text Available The management of terrestrial weed is of great concern for the scientific community as these weeds cause adverse effect in different ecosystems like forest, agriculture and urban. The widespread of these weeds by their adaptive capability and morphological advancement is difficult to control. Parthenium hysterophorous, Lantana camara, Saccharum spontaneum, Ageratum conyzoides are the weeds that spread all over the world. There are various management practices employed for the control of this weeds. But all of these practices have some drawbacks those are neither environment friendly nor economical. In this paper a review has been done to evaluate various alternative management practices for these terrestrial weeds and to analyze their feasibility. Vermicomposting and anaerobic digestion can be viable alternative option which is cost effective as well. There are few studies regarding vermicomposting and anaerobic digestions of terrestrial weeds are done.

  15. Studies on the performance of glyphosate in the control of graminaceous weeds in rice fields

    Energy Technology Data Exchange (ETDEWEB)

    Swamy, P M [Department of Botany, Sri Venkateswara Univ., Tirupati (India)

    1998-02-01

    Absorption and translocation of {sup 14}C-labelled glyphosate was studied from the commercial formulation `Roundup` to which three different surfactants, singly or in combination, four different oil adjuvants and ammonium sulfate were added. Increased penetration of the herbicide was observed after 1, 2 and 24 h by the addition of Triton X-100, ammonium sulfate and coconut oil. Addition of Neem oil instead of coconut oil also showed increased penetration after 24 h. Addition of Tween 80 and diesel oil increased the penetration with or without ammonium sulfate; whereas, Tween 20 with the added peanut oil or coconut oil and Tween 80 with Neem oil increased penetration only in the presence of ammonium sulfate. Therefore, the absorption of glyphosate seems to be dependent on the nature of surfactant and the oil (adjuvant) used. Field tests were carried out to study the effect of hand weeding, one dose of unamended and three different doses of amended (0.5, 0.75 and 1.5 kg a.i. ha{sup -1}) `Roundup` on weed control. The herbicide was applied at 9 am and 4 pm in cropped and uncropped plots. Visual rating, after 15 days suggested better control in hand weeded plots. However, this may be due to the fact that the hand weeding, was performed later than the herbicide application. Herbicide treatment with unamended Roundup resulted in significantly better weed control than the amended Roundup plots. (author). 31 refs, 9 tabs.

  16. Studies on the performance of glyphosate in the control of graminaceous weeds in rice fields

    International Nuclear Information System (INIS)

    Swamy, P.M.

    1998-01-01

    Absorption and translocation of 14 C-labelled glyphosate was studied from the commercial formulation 'Roundup' to which three different surfactants, singly or in combination, four different oil adjuvants and ammonium sulfate were added. Increased penetration of the herbicide was observed after 1, 2 and 24 h by the addition of Triton X-100, ammonium sulfate and coconut oil. Addition of Neem oil instead of coconut oil also showed increased penetration after 24 h. Addition of Tween 80 and diesel oil increased the penetration with or without ammonium sulfate; whereas, Tween 20 with the added peanut oil or coconut oil and Tween 80 with Neem oil increased penetration only in the presence of ammonium sulfate. Therefore, the absorption of glyphosate seems to be dependent on the nature of surfactant and the oil (adjuvant) used. Field tests were carried out to study the effect of hand weeding, one dose of unamended and three different doses of amended (0.5, 0.75 and 1.5 kg a.i. ha -1 ) 'Roundup' on weed control. The herbicide was applied at 9 am and 4 pm in cropped and uncropped plots. Visual rating, after 15 days suggested better control in hand weeded plots. However, this may be due to the fact that the hand weeding, was performed later than the herbicide application. Herbicide treatment with unamended Roundup resulted in significantly better weed control than the amended Roundup plots. (author)

  17. Effect of Integrated Weed Management Methods on Yield and Yield Components of Corn (Zea mays L. in Kermanshah Province, Iran

    Directory of Open Access Journals (Sweden)

    R. Amini

    2017-08-01

    +cultivator 40 days after emergence4- mechanical control (cultivator 25 and 40 days after emergence 5- cultural control (intercropping of corn with chickpea (Cicer arietinum L. at density of 200000 plants.ha-1 6- cultural control followed by other cultural control (planting hairy vetch in the fall +intercropping of corn with chickpea 7- chemical control followed by cultural control (application of glyphosate at a dose of 2050 g.a.i.ha-1 before planting+intercropping of corn with chickpea 8- cultural control (straw mulch application in the fall in amount of 2625 kg.ha-1 9- cultural control (straw mulch application in the spring in amount of 2625 kg.ha-1 10- hand weeding during whole season. Also the weed infested treatment was used as control. Sixty days after corn emergence, the weed sampling was done with 1×0.5 (0.5 m2 quadrate in each plot and weed density was recorded. The samples were dried in 75 ºC oven for 48 hours thenweed dry matter was measured. The plant height and leaf number per plant were measured in all plots. Corn was harvested at economic maturity and grain yield and yield components of corn and weed biomass were measured. The analysis of variance of data was performed using SPSS v.16 and Duncan's multiple range procedure was employed at probability level of 5%. Results and discussion: Results indicated that different weed management treatments had significant effect on weed density and dry matter, corn plant height, leaf number per plant, number of kernel rows per ear, number of kernels per row, number of kernels per ear and corn grain yield (p≤ 0.01. The lowest weed dry matter were obtained in 2, 4-D + MCPA+ cultivator treatment (72 g.m-2 and the highest one observed in intercropping with chickpea (440 g.m-2 and mulch application in the fall (441 g.m-2. The highest value of plant height, number of kernel rows per ear, number of kernels per row and number of kernels per ear were observed in 2,4-D + MCPA+ cultivator, nicosulfuron + cultivator and hairy

  18. Rust fungi on some poaceous weeds of wheat crops in Pakistan

    OpenAIRE

    NAJAM-UL-SEHAR AFSHAN*; ABDUL REHMAN NIAZI

    2013-01-01

    The article enlists common poaceous weeds found in wheat crop sand their specific parasitic rust fungi. In this study, four (04) plant taxa of Poaceae infected with rust fungi are collected from different wheat crops grown in different areas of Pakistan. The rust fungi are isolated, characterized and identified. All these host plants are known weeds of wheat crop in Pakistan. This work would help to identify and enlist the potential rust fungi on weeds of wheat crop that could be utilized to ...

  19. Weed control using ammonium nonanoate and cultivation in organic Vidalia sweet onion production

    Science.gov (United States)

    Ammonium nonanoate is registered for weed control in certified organic crop production and may be useful to control cool-season weeds in organic Vidalia® sweet onion. Cultivation with a tine weeder has been identified as a cost-effective means of weed control, but delays in cultivation cause some w...

  20. 7 CFR 201.65 - Noxious weed seeds in interstate commerce.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Noxious weed seeds in interstate commerce. 201.65 Section 201.65 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... ACT FEDERAL SEED ACT REGULATIONS Tolerances § 201.65 Noxious weed seeds in interstate commerce...

  1. Response of rice genotypes to weed competition in dry direct-seeded rice in India.

    Science.gov (United States)

    Mahajan, Gulshan; Ramesha, Mugalodi S; Chauhan, Bhagirath S

    2014-01-01

    The differential weed-competitive abilities of eight rice genotypes and the traits that may confer such attributes were investigated under partial weedy and weed-free conditions in naturally occurring weed flora in dry direct-seeded rice during the rainy seasons of 2011 and 2012 at Ludhiana, Punjab, India. The results showed genotypic differences in competitiveness against weeds. In weed-free plots, grain yield varied from 6.6 to 8.9 t ha(-1) across different genotypes; it was lowest for PR-115 and highest for the hybrid H-97158. In partial weedy plots, grain yield and weed biomass at flowering varied from 3.6 to 6.7 t ha(-1) and from 174 to 419 g m(-2), respectively. In partial weedy plots, grain yield was lowest for PR-115 and highest for PR-120. Average yield loss due to weed competition ranged from 21 to 46% in different rice genotypes. The study showed that early canopy closure, high leaf area index at early stage, and high root biomass and volume correlated positively with competitiveness. This study suggests that some traits (root biomass, leaf area index, and shoot biomass at the early stage) could play an important role in conferring weed competitiveness and these traits can be explored for dry-seeded rice.

  2. Studies on the Effect of Type and Solarization Period on Germination Percentage of Four Weed Species

    Directory of Open Access Journals (Sweden)

    J. Rostam

    2011-01-01

    Full Text Available Abstract In order to study the effects of soil solarization on weed control, an experiment with factorial arrangement in a randomized complete block design with four replications was conducted in a fallow farm in Daregaz in 2008. Factors included solarization duration (0, 2, 4 and 6 weeks and soil moisture content (dry and moist. Soil seed bank was sampled (in two depth, 0-10 and 10-20 cm prior to the experiment and immediately after applying treatments, and germination percentage of weed species were determined. Results of this study showed that seed germination percentage in 10 cm soil depth was influenced by soil moisture and solarization and their interactions, while in 20 cm soil depth only solarization period affected the weed seed germination. Germination percentage in moist soil was less than that in dry soil. Seed germination percentage declined more by increasing solarization duration, so that the greatest decline was obtained after 6 weeks solarization. Solarization decreased germination percentage in moist soil more than that in dry soil. Overall, the results of this experiment indicated that solarization of moist soil for 6 weeks was the most effective treatment in controlling common lambsquatres (Chenopodium album, common purslane (Portulaca oleracea, redroot pigweed (Amaranthus retroflexus, and wild mustard (Sinapis arvensis, while solarization of dry soil for 2 weeks was the least effective treatment for weed control. Keywords: Solarization, Soil moisture, Seed bank

  3. Are weeds hitchhiking a ride on your car? A systematic review of seed dispersal on cars.

    Directory of Open Access Journals (Sweden)

    Michael Ansong

    Full Text Available When traveling in cars, we can unintentionally carry and disperse weed seed; but which species, and where are they a problem? To answer these questions, we systematically searched the scientific literature to identify all original research studies that assess seed transported by cars and listed the species with seed on/in cars. From the 13 studies that fit these criteria, we found 626 species from 75 families that have seed that can be dispersed by cars. Of these, 599 are listed as weeds in some part of the world, with 439 listed as invasive or naturalized alien species in one or more European countries, 248 are invasive/noxious weeds in North America, 370 are naturalized alien species in Australia, 167 are alien species in India, 77 are invasive species in China and 23 are declared weeds/invaders in South Africa. One hundred and one are classified as internationally important environmental weeds. Although most (487 were only recorded once, some species such as Chenopodium album, Poa pratensis and Trifolium repens were common among studies. Perennial graminoids seem to be favoured over annual graminoids while annual forbs are favoured over perennial forbs. Species characteristics including seed size and morphology and where the plants grew affected the probability that their seed was transported by cars. Seeds can be found in many different places on cars including under the chassis, front and rear bumpers, wheel wells and rims, front and back mudguards, wheel arches, tyres and on interior floor mats. With increasing numbers of cars and expanding road networks in many regions, these results highlight the importance of cars as a dispersal mechanism, and how it may favour invasions by some species over others. Strategies to reduce the risk of seed dispersal by cars include reducing seed on cars by mowing road verges and cleaning cars.

  4. A fully convolutional network for weed mapping of unmanned aerial vehicle (UAV) imagery.

    Science.gov (United States)

    Huang, Huasheng; Deng, Jizhong; Lan, Yubin; Yang, Aqing; Deng, Xiaoling; Zhang, Lei

    2018-01-01

    Appropriate Site Specific Weed Management (SSWM) is crucial to ensure the crop yields. Within SSWM of large-scale area, remote sensing is a key technology to provide accurate weed distribution information. Compared with satellite and piloted aircraft remote sensing, unmanned aerial vehicle (UAV) is capable of capturing high spatial resolution imagery, which will provide more detailed information for weed mapping. The objective of this paper is to generate an accurate weed cover map based on UAV imagery. The UAV RGB imagery was collected in 2017 October over the rice field located in South China. The Fully Convolutional Network (FCN) method was proposed for weed mapping of the collected imagery. Transfer learning was used to improve generalization capability, and skip architecture was applied to increase the prediction accuracy. After that, the performance of FCN architecture was compared with Patch_based CNN algorithm and Pixel_based CNN method. Experimental results showed that our FCN method outperformed others, both in terms of accuracy and efficiency. The overall accuracy of the FCN approach was up to 0.935 and the accuracy for weed recognition was 0.883, which means that this algorithm is capable of generating accurate weed cover maps for the evaluated UAV imagery.

  5. Euphorbia davidii - an invasive weed species in the fields of Serbia

    Directory of Open Access Journals (Sweden)

    Vajgand Dragan K.

    2014-01-01

    Full Text Available Euphorbia davidii Subils (Euphorbiaceae or toothed spurge is a plant native to North America, but in Europe it is an alien weed. The populations of this weed were recorded in the Province of Vojvodina (Serbia for the first time in 2007 in the arable fields in two localities: between the villages of Aleksa Šantić and Pačir and also between the villages of Pačir and Đurđin. There were no previous published data about the occurrence of this species in Serbia, nor about management measures in crops to suppress this agricultural invader. In this paper, we present experiences with several herbicide treatments applied to suppress populations of toothed spurge from the crop fields in Serbia during the last six years. The most effective was treatment with a high concentration of glyphosate in the early phases of toothed spurge growing. The populations of this invasive weed spread and formed more or less dense patches in the crop field, the area of distribution increased from 3 ha to 7 ha. Observations and experiences with treatments suggest that Euphorbia davidii, as an invasive plant, has significant impact on crop fields, therefore further investigation of suppression measures and monitoring of its population is needed.

  6. Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut.

    Science.gov (United States)

    De Waele, D; Jordaan, E M; Basson, S

    1990-07-01

    The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed species; population densities increased in peanut hulls and caused severe damage to seeds of peanut grown after weeds. Roots of purple nutsedge left in the soil suppressed populations of D. destructor and root and pod development in peanut grown after the weed. However, nematode populations in peanut hulls and seeds were not suppressed. Some weed species, especially purple nutsedge which is common in peanut fields, can be used to indicate the presence of D. destructor in the absence of peanut.

  7. Designing, modeling and controlling a novel autonomous laser weeding system

    DEFF Research Database (Denmark)

    Shahrak Nadimi, Esmaeil; Andersson, Kim Johan; Jørgensen, Rasmus Nyholm

    2009-01-01

      Abstract: in this paper, the process of designing and developing a novel laser weeding test setup is explained. The main purpose of designing this system was to simulate the dynamic field conditions of a mobile vehicle capable of targeting weeds. This system consists of a rig containing three...

  8. A weed suppressive index for spring barley (Hordeum vulgare) varieties

    DEFF Research Database (Denmark)

    Hansen, P K; Kristensen, K; Willas, J

    2008-01-01

    A screening programme for crop variety competitiveness would ideally be based on only a few, non-destructive measurements of key growth traits. In this study we measured the weed suppressive ability of 79 varieties of spring barley in two ways: (i) directly, by weed coverage assessments under wee...

  9. Optimal weed management in crop rotations: incorporating economics is crucial

    NARCIS (Netherlands)

    Berg, van den F.; Gilligan, C.A.; Lemmen-Gerdessen, van J.C.; Gregoire, L.A.H.; Bosch, van den F.

    2010-01-01

    Although the effects of crop rotation sequence and length on weed population dynamics have been studied, it is not clear whether or not the best strategy, from a weed population dynamics point of view, is also the economic optimal strategy. It is also not clear which biological and economic

  10. Effects of pollutant accumulation by the invasive weed saltcedar (Tamarix ramosissima) on the biological control agent Diorhabda elongata (Coleoptera: Chrysomelidae)

    International Nuclear Information System (INIS)

    Sorensen, Mary A.; Parker, David R.; Trumble, John T.

    2009-01-01

    Hydroponic greenhouse studies were used to investigate the effect of four anthropogenic pollutants (perchlorate (ClO 4 - ), selenium (Se), manganese (Mn), and hexavalent chromium (Cr (VI))) on the biological control agent Diorhabda elongata Brulle. Contaminant concentrations were quantified for experimental Tamarix ramosissima Ledab. plants and D. elongata beetles. Growth of larvae was significantly reduced by Se contamination, but was not affected by the presence of perchlorate, Mn, or Cr (VI). All of the contaminants were transferred from plants to D. elongata beetles. Only Cr (VI) was accumulated at greater levels in beetles than in their food. Because T. ramosissima grows in disturbed areas, acquires salts readily, and utilizes groundwater, this plant is likely to accumulate anthropogenic pollutants in contaminated areas. This study is one of the first to investigate the potential of an anthropogenic pollutant to influence a weed biological control system. - The presence of Se, but not perchlorate, Mn, or Cr (VI), in foliage of the invasive weed saltcedar was shown to reduce growth of the biological control agent Diorhabda elongata

  11. Effects of pollutant accumulation by the invasive weed saltcedar (Tamarix ramosissima) on the biological control agent Diorhabda elongata (Coleoptera: Chrysomelidae)

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, Mary A. [Department of Entomology, University of California, Riverside, CA 92521 (United States)], E-mail: mary.sorensen@ucr.edu; Parker, David R. [Department of Environmental Science, University of California, Riverside, CA 92521 (United States); Trumble, John T. [Department of Entomology, University of California, Riverside, CA 92521 (United States)

    2009-02-15

    Hydroponic greenhouse studies were used to investigate the effect of four anthropogenic pollutants (perchlorate (ClO{sub 4}{sup -}), selenium (Se), manganese (Mn), and hexavalent chromium (Cr (VI))) on the biological control agent Diorhabda elongata Brulle. Contaminant concentrations were quantified for experimental Tamarix ramosissima Ledab. plants and D. elongata beetles. Growth of larvae was significantly reduced by Se contamination, but was not affected by the presence of perchlorate, Mn, or Cr (VI). All of the contaminants were transferred from plants to D. elongata beetles. Only Cr (VI) was accumulated at greater levels in beetles than in their food. Because T. ramosissima grows in disturbed areas, acquires salts readily, and utilizes groundwater, this plant is likely to accumulate anthropogenic pollutants in contaminated areas. This study is one of the first to investigate the potential of an anthropogenic pollutant to influence a weed biological control system. - The presence of Se, but not perchlorate, Mn, or Cr (VI), in foliage of the invasive weed saltcedar was shown to reduce growth of the biological control agent Diorhabda elongata.

  12. Phytotoxins produced by pathogenic fungi for the integrated management of noxious weeds

    OpenAIRE

    Cimmino, Alessio

    2008-01-01

    Weeds infest economically important crops causing marked losses in agrarian production, forests, and ornamental heritages. Weed pests, including parasitic plants, have always being recognised as one of the most serious agricultural and environmental problems due to competition with the growth of agrarian crops and forest plants by subtraction of water, nutrients, light and by the serious obstacles they represent for agronomic activities. A number of weed management strategies have been fo...

  13. Phenological observations on shrubs to predict weed emergence in turf

    Science.gov (United States)

    Masin, Roberta; Zuin, Maria Clara; Zanin, Giuseppe

    2005-09-01

    Phenology is the study of periodic biological events. If we can find easily recognizable events in common plants that precede or coincide with weed emergences, these plants could be used as indicators. Weed seedlings are usually difficult to detect in turf, so the use of phenological indicators may provide an alternative approach to predict the time when a weed appears and consequently guide management decisions. A study was undertaken to determine whether the phenological phases of some plants could serve as reliable indicators of time of weed emergence in turf. The phenology of six shrubs (Crataegus monogyna Jacq., Forsythia viridissima Lindl., Sambucus nigra L., Syringa vulgaris L., Rosa multiflora Thunb., Ziziphus jujuba Miller) and a perennial herbaceous plant [Cynodon dactylon (L.) Pers.] was observed and the emergence dynamics of four annual weed species [Digitaria sanguinalis (L.) Scop., Eleusine indica (L.) Gaertner, Setaria glauca (L.) Beauv., Setaria viridis (L.) Beauv.] were studied from 1999 to 2004 in northern Italy. A correlation between certain events and weed emergence was verified. S. vulgaris and F. viridissima appear to be the best indicators: there is a quite close correspondence between the appearance of D. sanguinalis and lilac flowering and between the beginning of emergence of E. indica and the end of lilac flowering; emergences of S. glauca and S. viridis were predicted well in relation to the end of forsythia flowering. Base temperatures and starting dates required to calculate the heat unit sums to reach and complete the flowering phase of the indicators were calculated using two different methods and the resultant cumulative growing degree days were compared.

  14. Weed diversity identification on growth phases of twelve maize varieties

    Science.gov (United States)

    Rahayu, M.; Yudono, P.; Indradewa, D.; Hanudin, E.

    2018-03-01

    Weed is one of the factors that disturb maize cultivation. Each maize variety has specific characteristics which will lead to weeds diversity in particular farm. This study aimed to identify the effect of maize variety on weed diversity on maize’s growth phases. The research was conducted from March to July 2016 in Banguntapan, Bantul, Yogyakarta, Indonesia. The field research was arranged by using Randomised Complete Block Design with three replications. The treatments were maize varieties, consist of 12 levels: ‘Bisi 18’, ‘Bisi 2’, ‘Pertiwi 3’, ‘NK 22’, ‘NK 33’, ‘DK 959’, ‘P23’, ‘DK 771’, ‘DK 95’, ‘Bima 19 Uri’, ‘Bisma’, and ‘Sukmaraga’. The results showed that at four weeks after planting (WAP) the most of weeds were growing on varieties ‘Bisi 18’, ‘NK 33’, ‘P 23’, and ‘DK 95’, there were 14 species. Bulbostylispuberula and Cyperusrotundus were growing on all maize varieties with the highest SDR on ‘Sukmaraga’ and ‘DK 959’. At six WAP, weeds that grew, most consists of four species of sedges, six species of grasses and 24 species of broadleaf. While at the age of eight WAP, the weeds that grow at least on ‘NK 33’ that were 13 species and the most on ‘P23’ that were 21 species. Dactyloctenium aeghypthium having highest SDR in all maize varieties except Bisi 18. The highest SDR value on Bisi 18 was Boerhaavia erecta about 16.23%.

  15. Evaluation of sowing patterns and weed control on mung bean (Vigna radiate L. Wilczek - black cumin (Nigella sativa L. intercropping system

    Directory of Open Access Journals (Sweden)

    parviz Rezvani Moghadam

    2016-04-01

    Full Text Available In order to study different arrangements and weed controls effects on mung bean (Vigna radiate L. Wilczek – black cumin (Nigella sativa L. intercropping an experiment was conducted at the Research Station of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during growing season 2005 – 2006. Sixteen treatments comprising combinations of eight sowing patterns [A1: Sole black cumin, A2: Sole mung bean, A3: 3 rows black cumin– 2 rows mung bean, A4: 3 rows black cumin – 2 rows mung bean, A5: 2 rows black cumin – 1 rows mung bean, A6: 1 row black cumin – 2 rows mung bean, A7: 3 rows black cumin – 3 rows mung bean (Striped, A8: 1 row black cumin – 1 row mung bean (alternative rows] and two weed controls [V1: unweeded, V2: completely hand weeding] were arranged in a factorial experiment based on randomized complete block design with three replications. Results showed that in intercropping systems leaf area index (LAI of mung bean reduced but in the case of black cumin increased. Mung bean total dry matter in intercropping system did not differ comparing with sole crop but total dry matter in black cumin increased. All yield components in both crops affected by sowing patterns and weed control treatments. Number of branches/plant, number of pods or follicules/plant and number of seed/pods or follicules increased in A8, A4, A5 and A3 sowing patterns in mung bean and A3, A5 and A7 sowing patterns in black cumin compared with other arrangements. By increasing mung bean ratio in rows, the number of weed species, weed density, dry weight of weeds and abundance of weed species decreased. In unweeded treatment, number of branches/plant, number of pods or follicules/plant and number of seed/pods or follicules decreased in both crops. Land equivalent ratio (LER was more than 1.00 in all sowing patterns.

  16. Preemergence herbicides on weed control in elephant grass pasture

    Directory of Open Access Journals (Sweden)

    Alexandre Magno Brighenti

    Full Text Available ABSTRACT Elephant grass (Pennisetum purpureum Schum. is an important forage crop that has been proposed as a potential feedstock for bioenergy production. However, weed interference is a major factor limiting elephant grass production. Field experiments were conducted in 2014 and 2015 to evaluate preemergence herbicides for selective weed control in an elephant grass pasture. Herbicide treatments included atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, diuron + hexazinone, sulfentrazone, imazethapyr, and atrazine at label use rates. Weedy and weed-free treatments were included. Atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine did not cause phytotoxicity on elephantgrass 35 days after treatment (DAT. However, diuron + hexazinone and imazethapyr were the most phytotoxic on elephantgrass, resulting in 81 and 70% phytotoxicity in 2014, and 7 and 6% phytotoxicity in 2015 respectively 35 DAT. All treatments provided effective weed control (>81% with the exception of ethoxysulfuron (0 and 11% in 2014 and 2015, respectively, and atrazine (59% in 2014. These results show that atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine were selectives when applied in preemergence in elephant grass pasture.

  17. Mechanical pre-planting weed control in short rotation coppice using deep forestry ploughing techniques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    This report describes a trial by Border biofuels to investigate the deep forestry plough as a mechanical pre-planting weed control method to reduce weed infestations in willow coppice and thus contribute to improved establishment and eventual yield. The results suggest that there was a considerable increase in biomass productivity from the deep ploughed area compared to the conventionally cultivated area at all three SRC sites tested. This technique also suggests that the deep forestry ploughing provides the benefit of much reduced levels of seed germination of many annual weed species and a reduction in levels of perennial weed infestation. It is not possible at this stage to predict the longer term benefits in terms of harvestable biomass productivity but it may be considered that the improved establishment and lack of weed competition would consistently produce higher yields of biomass than plantations which suffer from persistent and invasive weed competition. (author)

  18. Integrated weed management for sustainable rice production: concepts, perspectives and options

    International Nuclear Information System (INIS)

    Amartalingam Rajan

    2002-01-01

    Weed management has always been in some way integrated with cultural and biological methods, probably occurring more fortuitously than purposefully. Experience has shown that repeated use of any weed control technique especially in monocultures production systems results in rapid emergence of weeds more adapted to the new practice. In intensive high input farming systems, heavy selection pressure for herbicide tolerant weeds and the environmental impacts of these inputs are important tissues that require a good understanding of agroecosystem for successful integration of available options. Rice culture, in particular flooded rice culture has always employed integration through an evolution of management practices over the generations. However, a vast majority office farmers in Asia have yet to achieve the high returns realised by farmers elsewhere, where a near optimum combination of high inputs are being effectively integrated for maximum productivity. In addition to technological and management limitations, farmers in developing countries are faced with social, economic and policy constraints. On the other hand, farmers who had achieved considerable increases in productivity through labour replacing technologies, in particular direct seeding with the aid of herbicides, are now faced with issues related to environmental concerns due to high levels of these inputs. The issues facing weed scientists and farmers alike in managing weeds effectively and in a manner to ensure sustainability have become more challenging than ever before. In the last two decades, no issue has been discussed so. intensively as Sustainable Farming, Sustainable Agriculture or Alternative Agriculture within the broader global concept of Sustainable Development. To address these challenges a clear perspective of sustainable farming is essential. This paper addresses these concepts, perspectives and options for choices in weed management for sustainable rice production. (Author)

  19. Weed control changes and genetically modified herbicide tolerant crops in the USA 1996-2012.

    Science.gov (United States)

    Brookes, Graham

    2014-01-01

    the consequences of relying on a single or very limited number of herbicides for weed control. As a result, growers of GM HT crops have become much more proactive and diversified in their weed management programs in line with weed scientist recommendations and now include other herbicides (with different and complementary modes of action) in combination with glyphosate, even where instances of weed resistance to glyphosate have not been found. The willingness to proactively diversity weed management systems in the GM HT crops is also influenced by a desire to maintain effective weed control and hence continue to enjoy the benefits of no tillage and conservation tillage. Nevertheless, despite the increase in herbicide use in recent years, the use of GM HT technology continues to deliver significant economic and environmental gains to US farmers.

  20. Genetically Modified Herbicide-Tolerant Crops, Weeds, and Herbicides: Overview and Impact

    Science.gov (United States)

    Bonny, Sylvie

    2016-01-01

    Genetically modified (GM) crops have been and continue to be a subject of controversy despite their rapid adoption by farmers where approved. For the last two decades, an important matter of debate has been their impact on pesticide use, particularly for herbicide-tolerant (HT) crops. Some claim that these crops bring about a decrease in herbicide use, while others claim the opposite. In fact, since 1996, most cultivated GMOs have been GMHT crops, which involve the use of an associated herbicide, generally glyphosate. In their very first years of adoption, HT crops often led to some decrease in herbicide use. However, the repetition of glyphosate-tolerant crops and of glyphosate only applications in the same fields without sufficient alternation and herbicide diversity has contributed to the appearance of glyphosate-resistant weeds. These weeds have resulted in a rise in the use of glyphosate and other herbicides. This article explores this situation and the impacts of herbicide-resistant weeds, using an interdisciplinary approach and drawing on recent data. The paper analyzes the spread of GMHT crops worldwide and their consequences on herbicide use in the USA in particular. It then addresses the global development of glyphosate-resistant weeds and their impact, particularly focusing on the USA. Finally, the last section explores how industry, farmers, and weed scientists are coping with the spread of resistant weeds. The concluding comments deal more widely with trends in GM crops.

  1. Mechanical weed control in organic winter wheat

    OpenAIRE

    Euro Pannacci; Francesco Tei; Marcello Guiducci

    2017-01-01

    Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006- 07; exp. 3, 2007-08) in central Italy (42°57’ N - 12°22’ E, 165 m a.s.l.) in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: i) spring tine harrowing used at three different application times (1 passage at T1, 2 passages at the time T1, 1 passage at T1 followed by 1 passage at T1 + 14 days) in t...

  2. Critical Period for Weed Removal in Garden Egg (Solanum Incanum ...

    African Journals Online (AJOL)

    Field experiments were conducted at the Teaching and Research Farm, Adeyemi College of Education, Ondo during the 2004 and 2005 cropping seasons to determine the extent of yield loss due to weed infestation and the critical time for weed removal in garden egg (Solanum incanum). The experiment which was ...

  3. Effect of weed management methods and nitrogen fertilizer rates on ...

    African Journals Online (AJOL)

    Inefficient weed management practices and the use of inappropriate nitrogen fertilizer rates are the major causes of low yield of wheat in Ethiopia. Therefore, field experiments were conducted at Bobicho and Faate in southern Ethiopia to determine the effect of weed management practices and N fertilizer rates on grain yield ...

  4. Managing invasive plants in natural areas: Moving beyond weed control

    Science.gov (United States)

    Dean Pearson; Yvette Ortega

    2009-01-01

    Exotic invasive plants present one of the greatest challenges to natural resource management. These weeds can alter entire communities and ecosystems, substantially degrading important ecosystem services such as forage for wild and domestic herbivores, water and soil quality, recreational values, and wildlife habitat. Traditionally, weed management in natural areas has...

  5. PERIODS OF WEED INTERFERENCE ON TRANSGENIC COTTON ‘IMACD 6001LL’

    Directory of Open Access Journals (Sweden)

    MARCOS PAULO DA SILVA

    2016-01-01

    Full Text Available The objective of this study was to determine the periods of weed interference and its impact on productivity of cotton 'IMACD 6001LL'. The experiment was conducted in Jaboticabal, São Paulo, the second crop in 2011 and consisted of two treatment groups: the first culture remained free of competing weeds since of emergence up different periods of its development: (0-15 , 0-25, 0-35, 0-45, 0-55, 0-65, 0-75 and 0-183 days - harvest. In the second treatment group was held to the contrary: the crop was in harmony with the weeds since of emergence up to the same stages of development described above. The treatments were arranged in a randomized block design in four replications. During these periods was evaluated dry matter accumulation by weeds. The cotton yield data were subjected to regression analysis and resulting in a CPWC of 35 DAE, the CPWR was 133 DAE and .The weed community was composed mainly of Raphanus raphanistrum, Amaranthus spp., Cyperus rotundus, Alternanthera tenella and Eleusine indica. Living with this community throughout the cycle resulted in reduction almost 85% in cotton yield.

  6. WEED FLORA OF CASSAVA IN WEST NILE ZONES OF UGANDA ...

    African Journals Online (AJOL)

    ACSS

    Information on weeds of cassava (Manihot esculenta Crantz) in eastern Africa is limited. The objective of this study was to establish the status of weed flora in selected cassava growing regions of Uganda. This study was conducted in 2013 at Abi Zonal Agricultural Research and Development Institute; (AbiZARDI) in Arua, ...

  7. Weed control through crop rotation and alternative management practices

    Directory of Open Access Journals (Sweden)

    Böhm, Herwart

    2014-02-01

    Full Text Available Economic as well as agricultural and socio-political changes have an impact on crop management and thus also on crop rotation design and the related effects on the weed flora. Likewise other changes in cultivation such as reduced tillage practices, earlier sowing date, etc. cause an increase in weed infestation resp. an increased use of herbicides and if so contribute to herbicide resistance. The positive effects of crop rotation, but also of alternative management practices such as choice of varieties, catch crops, mixed cropping, green chop, and the share of predators, as well as methods of direct non-chemical weed control are presented and discussed for both, conventional and organic farming. If alternative management methods should be more practiced, especially trade-offs need to be broken, or incentives be offered.

  8. Evaluation of Growth and Species Composition of Weeds in Maize-Cowpea Intercropping based on Additive Series under Organic Farming Condition

    Directory of Open Access Journals (Sweden)

    Hamdollah Eskandari

    2016-11-01

    relative yield total (RYT index. Weed smothering efficiency (WSE was used to evaluate the effect of intercropping on reducing weeds the dry weight. Results and discussion Results indicated that soil moisture content, PAR interception and soil temperature were affected by cropping patterns. The lowest and highest values of soil temperatures were observed in intercropping and sole crop systems, respectively. Intercropping systems exploited soil water more than sole crops. PAR interception was higher in intercropping compared to sole cropping. However, sole cowpea showed lower PAR interception compared to maize sole crop. Relative yield total (RYT index was more than unity in all intercropping systems. Weed smothering efficiency (WSE showed that dry weight of weeds was reduced by 21-26 and 28-42 percentages in intercropping systems compared to sole maize and sole cowpea cropping systems, respectively. The growth of weeds (in terms of total dry weight in intercropping systems were reduced in which from five recorded weed species, the dry weight of them, including amaranth (Amaranthus retondus L., pigweed (Echinocloa cruss-gali L., purslane (Portulaca oleraceae L. and Halikakabon (Solanum nigrum L. decreased in intercropping compared to sole cropping systems. Intercropping components showed a complementary relation in consuming environmental resources including soil moisture and PAR. Since the soil temperature was lower in intercropping compared to sole cropping, lower soil moisture in intercropping cannot be resulted from higher evaporation in intercropping, but also the widespread root system in intercropping resulted in higher efficiency in soil moisture consuming. Relative yield total more than unity, showing the advantages of intercropping in environmental resources consumption. Soil covering and higher biodiversity are two main factors reducing weeds growth in intercropping because the two recent factors lower PAR availability for weeds which can reduce weed. The current

  9. The value of precision for image-based decision support in weed management

    DEFF Research Database (Denmark)

    Franco de los Ríos, Camilo; Pedersen, Søren Marcus; Papaharalampos, Haris

    2017-01-01

    Decision support methodologies in precision agriculture should integrate the different dimensions composing the added complexity of operational decision problems. Special attention has to be given to the adequate knowledge extraction techniques for making sense of the collected data, processing...... the information for assessing decision makers and farmers in the efficient and sustainable management of the field. Focusing on weed management, the integration of operational aspects for weed spraying is an open challenge for modeling the farmers’ decision problem, identifying satisfactory solutions...... for the implementation of automatic weed recognition procedures. The objective of this paper is to develop a decision support methodology for detecting the undesired weed from aerial images, building an image-based viewpoint consisting in relevant operational knowledge for applying precision spraying. In this way...

  10. Isolation and characterization of deleterious Pseudomonas aeruginosa KC1 from rhizospheric soils and its interaction with weed seedlings

    Directory of Open Access Journals (Sweden)

    Vijaya Lakshmi

    2015-04-01

    Full Text Available The bacterial isolate KC1 was screened from the rhizosphere of castor plants (Ricinus communis indigenous to agricultural fields of Bihar. The isolate was Gram negative, non-spore forming, and exhibited fluorescence under UV light. Its molecular characterization is based on the sequencing of 16S rDNA (1450 bp and alignment at GeneBank (NCBI, MaryLand. The strain has been validated as Pseudomonas aeruginosa (HM195190. The bacterium grew at 4–42 °C, with a temperature optima of 30 °C. The strain KC1 was found to produce cyanide (4.78 nmol l−1 over a period of 36 h. Data revealed enhanced cyanogenesis (6.98 nmol l−1, when glycine was provided in the King’s B medium. Seed bacterization exhibited reduction in root length, shoot length of weed seedlings (Amaranthus spinosus, Portulaca oleracea, which was significant (p < 0.05 in both laboratory and glasshouse experiments. Biomass was significantly reduced (p < 0.05 for the weed seedlings in glasshouse experiments. However, KC1 inoculated crop seedlings (Triticum aestivum were found to be less inhibitory as compared to weed seedlings. The observations are significant to establish, that the secondary metabolites producing KC1 rhizobacterium, P. aeruginosa KC1 could be exploited as a weed biocontrol agent. The innate potential of KC1 could be further formulated and utilized in field applications for agricultural sustainability.

  11. Weed management at ArborGen, South Carolina SuperTree Nursery

    Science.gov (United States)

    Mike Arnette

    2009-01-01

    Weed management is vital to producing healthy hardwood seedlings. Several methods are available to each nursery, and it is common knowledge that what works for one situation may not work for another. The weed control methods used in nursery beds of hardwood species at the South Carolina SuperTree Nursery (Blenheim) are listed below.

  12. COMPETITION AND FACILITATION EFFECTS OF DIFFERENTIAL INTRA-AND INTER-ROW WEED MANAGEMENT IN SUGARCANE

    OpenAIRE

    Martin , J; Chabalier , M; Letourmy , P; Chopart , J.-L; Arhiman , E; Marion , D

    2013-01-01

    International audience; Differential intra-and inter-row weed management can be a mean to reduce herbicide use in sugarcane. In 2011, a field experiment was conducted in La Reunion Island to assess inter-row weed competition. Four inter-row weed competition treatments for a duration of one (T1), two (T2), three (T3) and four (T4) months after planting were compared in a randomized complete block design with 5 replicates; treatment plots were paired with non-weeded inter-row control plots. All...

  13. Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut

    OpenAIRE

    De Waele, D.; Jordaan, Elizabeth M.; Basson, Selmaré

    1990-01-01

    The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed spec...

  14. Potential use of ground-based sensor technologies for weed detection.

    Science.gov (United States)

    Peteinatos, Gerassimos G; Weis, Martin; Andújar, Dionisio; Rueda Ayala, Victor; Gerhards, Roland

    2014-02-01

    Site-specific weed management is the part of precision agriculture (PA) that tries to effectively control weed infestations with the least economical and environmental burdens. This can be achieved with the aid of ground-based or near-range sensors in combination with decision rules and precise application technologies. Near-range sensor technologies, developed for mounting on a vehicle, have been emerging for PA applications during the last three decades. These technologies focus on identifying plants and measuring their physiological status with the aid of their spectral and morphological characteristics. Cameras, spectrometers, fluorometers and distance sensors are the most prominent sensors for PA applications. The objective of this article is to describe-ground based sensors that have the potential to be used for weed detection and measurement of weed infestation level. An overview of current sensor systems is presented, describing their concepts, results that have been achieved, already utilized commercial systems and problems that persist. A perspective for the development of these sensors is given. © 2013 Society of Chemical Industry.

  15. Environmental mobile robot based on artificial intelligence and visual perception for weed elimination

    Directory of Open Access Journals (Sweden)

    Nabeel Kadim Abid AL-SAHIB

    2012-12-01

    Full Text Available This research presents a new editing design for the pioneer p3-dx mobile robot by adding a mechanical gripper for eliminating the weed and a digital camera for capturing the image of the field. Also, a wireless kit that makes control on the motor's gripper is envisaged. This work consists of two parts. The theoretical part contains a program to read the image and discover the weed coordinates which will be sent to the path planning software to discover the locations of weed, green plant and sick plant. These positions are sent then to the mobile robot navigation software. Then the wireless signal is sent to the gripper. The experimental part is represented as a digital camera that takes an image of the agricultural field, and then sends it to the computer for processing. After that the weeds coordinates are sent to the mobile robots by mobile robot navigation software. Next, the wireless signal is sent to the wireless kit controlling the motor gripper by the computer interface program; the first trial on the agricultural field shows that the mobile robot can discriminate the green plant, from weed and sick plant and can take the right decision with respect to treatment or elimination. The experimental work shows that the environmental mobile robot can detect successfully the weed, sick plant and the hale plant. The mobile robot also travels from base to the target point represented by the weed and sick plants in the optimum path. The experimental work also shows that the environmental mobile robot can eliminate the weed and cure the sick plants in a correctly way.

  16. Ecophysiological responses of a young blue gum (Eucalyptus globulus) plantation to weed control.

    Science.gov (United States)

    Eyles, Alieta; Worledge, Dale; Sands, Peter; Ottenschlaeger, Maria L; Paterson, Steve C; Mendham, Daniel; O'Grady, Anthony P

    2012-08-01

    Early weed control may improve the growth of forest plantations by influencing soil water and nutrient availability. To understand eucalypt growth responses to weed control, we examined the temporal responses of leaf gas-exchange, leaf nitrogen concentration (N) and water status of 7-month-old Eucalyptus globulus L. trees in a paired-plot field trial. In addition, we monitored the growth, leaf N and water status of the competing vegetation in the weed treatment. By the end of the 11-month experiment, complete weed control (WF treatment) of largely woody competitors increased the basal diameter of E. globulus by 14%. As indicated by pre-dawn water potentials of > - 0.05 MPa, interspecies competition for water resources was minimal at this site. In contrast, competition for N appeared to be the major factor limiting growth. Estimations of total plot leaf N (g m(-2) ground) showed that competing vegetation accounted for up to 70% of the total leaf N at the start of the trial. This value fell to 15% by the end of the trial. Despite increased leaf N(area) in WF trees 5 months after imposition of weed control, the photosynthetic capacity (A(1500)) of E. globulus was unaffected by treatment suggesting that the growth gains from weed control were largely unrelated to changes in leaf-level photosynthesis. Increased nutrient availability brought about by weed control enabled trees to increase investment into leaf-area production. Estimates of whole-tree carbon budget based on direct measurements of dark respiration and A(1500) allowed us to clearly demonstrate the importance of leaf area driving greater productivity following early weed control in a nutrient-limited site.

  17. Investigating the Effect of Chemical Management on Weeds Population, Agronomical Traits and Yield of Garlic (Allium sativum L. in Mazandaran Province

    Directory of Open Access Journals (Sweden)

    Sobhan Mahzari

    2018-02-01

    Full Text Available Introduction: Garlic (Allium sativum L. is an important winter crop in northern of Iran with a total of 9580 ha which produces approximately 90, 197 tons per year. It is the second most widely cultivated species of the genus, Allium after onion (Allium cepa. Also, Garlic along with onions and leeks are three major cultivated species in Alliaceae family. This plant because of high economic and medicinal values is cultivated in 2610 hectares of agricultural lands of Mazandaran Province, Iran. Slow growth rate, low height, and a thin canopy that does not cover the soil enough to sup-press weeds make garlic a poor competitor against the latter until the beginning of spring. According results, reported 71% yield losses in garlic crop if weeds are allowed to grow during the crop season. Weed interference is affected by the time of weed emergence relative to the crop’s phenological development. The weeds, which emerge early or simultaneously with the crop, are highly competitive and should be managed by farmers. Most weed management strategies in cereals target seedlings, as they are the most sensitive stage of the weed. However, emergence of weed seedlings varies every year in timing, extent and intensity. Therefore in this study, the effect of chemical management on reducing the density and biomass of weeds, yield and agronomic characteristics of garlic were studied in Mazandaran Province, Iran. Materials and Methods: After the selection of location test, in order to determine the physical and chemical properties before the preparation of soil for planting, sampling from the soil was carried out from the depth of 0 to 30 cm at some point. The farm was plowed using a moldboard plow, then the used fertilizers in this study were added to the soil twice before planting and then the fertilizers were incorporated with the soil using a Disc. The amount of used fertilizers in this study according to soil test were including: 200 kg Urea per hectare that

  18. To be or not to be - common and endangered arable weed species in the face of Global Climate Change

    Directory of Open Access Journals (Sweden)

    Rühl, Anna Theresa

    2014-02-01

    Full Text Available Arable weeds are one of the most endangered species groups in Europe. Modern agriculture and intensive land use management with the application of herbicides and fertilisers, enhanced seed cleaning, simplified crop rotations and abandonment of marginal arable sites are the main causes for the continuous decline of arable weeds. However, besides these changes in land use also global climate change may challenge the adaptability of arable weeds. Most scientists agree that the frequency of extreme meteorological conditions will increase in the future. As a consequence, plants of Central Europe will be subject to higher temperatures and reduced water supply due to longer intervals without precipitation during the growing season. We exposed seeds of five common and five endangered arable weed species to different temperatures and water potentials to study i how this plant group responds to higher temperatures and lower moisture during germination in general and ii whether there is a significant difference between common and endangered species in this respect.

  19. Irradiation effects for the growth inhibition of weed seeds invaded from foreign countries

    International Nuclear Information System (INIS)

    Takatani, Yasuyuki; Ito, Hitoshi

    1999-01-01

    Weeds of foreign origin have been invaded through imported maize or dried grass which using for animal feeds, and causing serious damages to agricultural crops and farm animals in Japan. These weeds are spreading mainly through animal feeds to feces. For the purpose to decrease the damage from these weeds, we investigated the gamma-irradiation effect on 7 species of the weed seed to suppress the germination or elongation of stem and root. After the irradiation of the weed seeds, all species kept the ability of germination even at 4 kGy in petri dish cultivation, whereas decreased the germination ratio in some species. However, many species of weed decreased the ability on elongation of stem or root below l kGy irradiation. Furthermore, all of species lost the ability on the development of root hair and appearance of first leaf after germination of seeds below 1 kGy irradiation. From this study, necessary dose for growth inhibition was estimated to be 1 kGy which should be able to apply with combination treatment of the animal feeds for elimination of pathogenic bacteria such as salmonellae at 3 to 5 kGy irradiation. (author)

  20. Diversity of segetal weeds in pea (Pisum sativum L. depending on crops chosen for a crop rotation system

    Directory of Open Access Journals (Sweden)

    Marta K. Kostrzewska

    2014-04-01

    Full Text Available This study, lasting from 1999 to 2006, was conducted at the Research Station in Tomaszkowo, which belongs to the University of Warmia and Mazury in Olsztyn. The experiment was set up on brown rusty soil classified as good rye complex 5 in the Polish soil valuation system. The analysis comprised weeds in fields sown with pea cultivated in two four-field crop rotation systems with a different first crop: A. potato – spring barley – pea – spring barley; B. mixture of spring barley with pea – spring barley – pea – spring barley. Every year, at the 2–3 true leaf stage of pea, the species composition and density of individual weed species were determined; in addition, before harvesting the main crop, the dry matter of weeds was weighed. The results were used to analyze the constancy of weed taxa, species diversity, and the evenness and dominance indices, to determine the relationships between all biological indicators analyzed and weather conditions, and to calculate the indices of similarity, in terms of species composition, density and biomass of weeds, between the crop rotations compared. The species richness, density and biomass of weeds in fields with field pea were not differentiated by the choice of the initial crop in a given rotation system. In the spring, the total number of identified taxa was 28 and it increased to 36 before the harvest of pea plants. Chenopodium album and Echinochloa crus-galli were the most numerous. Chenopodium album, Echinochloa crus-galli, Sonchus arvensis, Fallopia convolvulus and Viola arvensis were constant in all treatments, regardless of what the first crop in rotation was or when the observations were made. The species diversity and the evenness and species dominance indices varied significantly between years and dates of observations. Species diversity calculated on the basis of the density of weed species was higher in the rotation with a mixture of cereals and legumes, while that calculated on

  1. The Astrophysical Weeds: Rotational Transitions in Excited Vibrational States

    Science.gov (United States)

    Alonso, José L.; Kolesniková, Lucie; Alonso, Elena R.; Mata, Santiago

    2017-06-01

    The number of unidentified lines in the millimeter and submillimeter wave surveys of the interstellar medium has grown rapidly. The major contributions are due to rotational transitions in excited vibrational states of a relatively few molecules that are called the astrophysical weeds. necessary data to deal with spectral lines from astrophysical weeds species can be obtained from detailed laboratory rotational measurements in the microwave and millimeter wave region. A general procedure is being used at Valladolid combining different time and/or frequency domain spectroscopic tools of varying importance for providing the precise set of spectroscopic constants that could be used to search for this species in the ISM. This is illustrated in the present contribution through its application to several significant examples. Fortman, S. M., Medvedev, I. R., Neese, C.F., & De Lucia, F.C. 2010, ApJ,725, 1682 Rotational Spectra in 29 Vibrationally Excited States of Interstellar Aminoacetonitrile, L. Kolesniková, E. R. Alonso, S. Mata, and J. L. Alonso, The Astrophysical Journal Supplement Series 2017, (in press).

  2. Parasitic weed incidence and related economic losses in rice in Africa

    NARCIS (Netherlands)

    Rodenburg, Jonne; Demont, Matty; Zwart, Sander J.; Bastiaans, Lammert

    2016-01-01

    Parasitic weeds pose increasing threats to rain-fed rice production in Africa. Most important species are Striga asiatica, S. aspera and S. hermonthica in rain-fed uplands, and Rhamphicarpa fistulosa in rain-fed lowlands. Information on the regional spread and economic importance of parasitic weeds

  3. Survey of weed composition befor maize sowing in long-term fertilization experiment.

    Science.gov (United States)

    Kismányoky, A; Lehoczky, E

    2007-01-01

    The study was carried out in a long-term fertilization field experiment of the Experimental Station of University of Pannonia, Department of Crop Science and Soil Science in 2006. The Long-term fertilization experiment was set up in 1983. In the experiment, the success of the weeds ability to grow under the influence of NPK, NPK + FYM* and NPK + straw treatments was compared, and the effect of increasing Nitrogen dosing on weediness was studied. The bifactorial test was arranged in split plot design with three replications. Treatment A: nutrient: NPK, NPK + 35 t/ha FYM* and NPK + straw manure. Treatment B: N kg/ha(-1) N0-N4 (0, 70, 140, 210, 280), and 100 kg P2O5 ha(-1) & 100 kg K20. The weed survey was made on 2nd of May 2006. There were spraying no herbicide until the survey. For the weed survey the Balázs-Ujvárosi coenological method was applied. Altogether, we have found 23 weed species in the trial. In the NPK treatment there were 20 species, in the treatment NPK+organic manure there were 17 species and in the NPK+ stalk rest treatment there were 16 weed species. The most dominant of the weeds on the NPK and NPK+straw manure treatments was Veronica hederifolia while on the fertilizer + FYM, the A. theophrasti was most dominant. The average weed covering value of the treatment NPK + FYM was 1.36 times higher (10.87%) than that of treatment NPK only (7.97%) and 3.65 times higher than on the NPK + straw manure treatment.

  4. Potential uses of small unmanned aircraft systems (UAS) in weed research

    DEFF Research Database (Denmark)

    Rasmussen, Jesper; Nielsen, Jon; Garcia Ruiz, Francisco Jose

    2013-01-01

    applications in UAS imagery weed research. In two experiments with post-emergence weed harrowing in barley, the crop resistance parameter, which reflects the crop response to harrowing, was unaffected by image capture altitude in the range from 1 to 50 m. This corresponded to image spatial resolution...... with ground truth data. UAS imagery also gave excellent results in logarithmic sprayer experiments in oilseed rape, where we captured 37 m long plots in each image from an altitude of 35 m. Furthermore, perennial weeds could be mapped from UAS images. These first experiences with a small rotary-wing UAS show...

  5. Pre-harvest assessment of perennial weeds in cereals based on images from unmanned aerial systems (UAS)

    DEFF Research Database (Denmark)

    Egilsson, Jon; Pedersen, Kim Steenstrup; Olsen, Søren Ingvor

    2015-01-01

    Unmanned aerial systems (UAS) are able to deliver images of agricultural fields of high spatial and temporal resolution. It is, however, not trivial to extract quantitative information about weed infestations from images. This study contributes to weed research by using state-of-the-art computer....... In order to provide ground truth prior to the modeling phase in Python, a subset of 600 images was annotated by experts with 16000 regions of weeds or crop. Following this, images were segmented into regions with weeds or crop by subdividing each image into 64 by 64 pixel patches and classifying each patch...... as either crop or weed. A collection of geo-referenced segmented images may subsequently be used to map weed occurrences in fields. To find a robust and fully automated assessment method both texture and color information was used to build a number of different competing weed-crop classifiers, including...

  6. Dicotyledon Weed Quantification Algorithm for Selective Herbicide Application in Maize Crops.

    Science.gov (United States)

    Laursen, Morten Stigaard; Jørgensen, Rasmus Nyholm; Midtiby, Henrik Skov; Jensen, Kjeld; Christiansen, Martin Peter; Giselsson, Thomas Mosgaard; Mortensen, Anders Krogh; Jensen, Peter Kryger

    2016-11-04

    The stricter legislation within the European Union for the regulation of herbicides that are prone to leaching causes a greater economic burden on the agricultural industry through taxation. Owing to the increased economic burden, research in reducing herbicide usage has been prompted. High-resolution images from digital cameras support the studying of plant characteristics. These images can also be utilized to analyze shape and texture characteristics for weed identification. Instead of detecting weed patches, weed density can be estimated at a sub-patch level, through which even the identification of a single plant is possible. The aim of this study is to adapt the monocot and dicot coverage ratio vision (MoDiCoVi) algorithm to estimate dicotyledon leaf cover, perform grid spraying in real time, and present initial results in terms of potential herbicide savings in maize. The authors designed and executed an automated, large-scale field trial supported by the Armadillo autonomous tool carrier robot. The field trial consisted of 299 maize plots. Half of the plots (parcels) were planned with additional seeded weeds; the other half were planned with naturally occurring weeds. The in-situ evaluation showed that, compared to conventional broadcast spraying, the proposed method can reduce herbicide usage by 65% without measurable loss in biological effect.

  7. Pseudomonas syringae pv. phaseolicola isolated from weeds in bean crop fields.

    Science.gov (United States)

    Fernández-Sanz, A M; Rodicio, M R; González, A J

    2016-04-01

    Pseudomonas syringae pv. phaseolicola, the causative agent of halo blight in common bean (Phaseolus vulgaris L.), was isolated from weeds associated with bean crops in Spain. The bacterium was recovered from Fumaria sp, Mercurialis annua, Solanum nigrum and Sonchus oleraceus. Ps. s. pv. phaseolicola had previously been isolated from leguminous plants and S. nigrum, but to our knowledge, this is the first time it was recovered from the other three species. The isolates were phenotypically and genetically characterized, and they were compared with isolates recovered from common beans. Five different genotypic profiles were detected by PmeI-PFGE, two of them being of new description. Weed isolates were as pathogenic on bean plants as bean isolates, but they were not pathogenic on S. nigrum. Regarding the survival of the pathogen in weeds, Ps. s. pv. phaseolicola was isolated from So. oleraceus 11 weeks after the end of the bean crop. These results strongly support the idea of weeds as a potential source of inoculum for halo blight in bean. It has traditionally been considered that the main source of inoculum of Pseudomonas syringae pv. phaseolicola causing halo blight disease in Phaseolus vulgaris are the bean seeds, and that the host range of the bacterium is almost restricted to leguminous plants. In this study, the bacterium was recovered from four nonleguminous weed species collected in bean fields, and its permanence in weeds for at least 11 weeks after the harvesting of the beans was demonstrated. We have also proved that the strains isolated from weeds were pathogenic on bean plants. Accordingly, the host range of Ps. s. pv. phaseolicola could be broader than previously thought and weeds appear to be acting as a reservoir of the pathogen until the next crop. © 2016 The Society for Applied Microbiology.

  8. Effect of weed patch size on seed removal by harvester ants

    Directory of Open Access Journals (Sweden)

    Westermann, Paula R.

    2014-02-01

    Full Text Available In dryland cereals in North-eastern Spain, the harvester ant, Messor barbarus L., is responsible for removal of a large proportion of the newly produced weed seeds (40-100%. The probability that seeds will be found by the ants may be influenced by weed patch size. To investigate this source of variability, 30 seed patches were created in each of three, 50 × 50 m, blocks in a cereal field after harvest, by sequentially seeding (10, 16 and 17 August 2010 with 2000 seeds m-2 of Avena sativa L.. Patch size varied from 0.25 to 9 m2. Twenty four hours after seeding, the remaining seeds were collected and seed removal rates estimated. Average seed removal rate was lowest in the smallest (78-94% and highest in the largest patches (99-100%. Differences were mainly caused by the fact that some of the smaller patches (9.7% were not found. However, when patches were found, they were exploited at equal rates (98-100%. As predicted, the probability of finding a patch increased slightly, but significantly, with increasing patch size. When a patch was found, it was almost always fully exploited, resulting in very high seed removal rates, irrespective of patch size. These results indicate that the size of the seed patch is only a minor source of variation influencing this form of biological control of weeds.

  9. Weed infestation of a cereal-legume mixture depending on its concentration and position in a crop rotation

    Directory of Open Access Journals (Sweden)

    Marta K. Kostrzewska

    2012-10-01

    Full Text Available A field study was carried out in the period 2000-2006 at the Experimental Station in Tomaszkowo belonging to the University of Warmia and Mazury in Olsztyn. Its aim was to compare weed infestation of a mixture of spring barley and field pea grown in a four crop rotation with different crop selection and sequence. Each year during tillering of spring barley and before the harvest of the mixture, weed species composition and density were evaluated, while additionally weed biomass was also estimated before the harvest. These results were used to determine species constancy, Simpson’s dominance index, the Shannon-Wiener diversity and evenness indices as well as the community similarity index based on floristic richness, numbers and biomass of particular weed species. The cropping frequency and the position of the mixture in the crop rotation did not differentiate the species composition and total biomass of weed communities in the cereal-legume mixture crops. The crop rotation in which the mixture constituted 50% and was grown after itself had a reducing effect on weed numbers. Growing field pea in the 4-year crop rotation promoted weed infestation of the mixture and the dominance of weed communities. Capsella bursa-pastoris, Chenopodium album, Echinochloa crus-galli, Elymus repens, Polygonum convolvulus, and Sonchus arvensis were constant components of the agrophytocenoses. The weed communities were more similar in terms of their floristic composition than in terms of weed density and air-dry weight of weeds.

  10. The effect of environmental conditions on the seasonal dormancy pattern and germination of weed seeds

    NARCIS (Netherlands)

    Bouwmeester, H.J.

    1990-01-01

    Weeds cause considerable losses in horticultural and agricultural crops. Weeds are still predominantly controlled with herbicides. To reduce the use of chemicals, a better understanding of the biology of weeds is required. In this thesis the effect of environmental conditions on dormancy

  11. Chemical and Mechanical Weed Control Methods and Their Effects on Photosynthetic Pigments and Grain Yield of Kidney Bean

    Directory of Open Access Journals (Sweden)

    A.S Ghatari

    2015-11-01

    Full Text Available To evaluate the integrated management of weeds in red kidney bean, a split-plot experiment using randomized complete block design with three replications was conducted in 2013 in the Damavand County. In this experiment, the mechanical control treatments consisted of two levels (no cultivation and one cultivation asseigned to main plots and controlling chemical treatments consisted of six levels (non-application of herbicides, pre-emergence herbicide application of Pursuit with full dose of 1 liter per hectare, pre-emergence herbicide application of Pursuit a dose decreased 0.5 liters per hectare, post-emergence herbicide application of Pursuit dose reduced to 0.3 liters per hectare + 2 thousand citogate, post-emergence herbicide application of Pursuit with a reduced dose of 0.5 liters per hectare + 2 thousand citogate, post-emergence herbicide application of Pursuit full dose of 1 liter per hectar + 2 thousand citogate to subplots. The results showed that the effects of interaction between herbicide application and cultivation for traits of carotenoids, chlorophyll a, chlorophyll b and total chlorophyll contents, density of weeds and their dry weights were significant at 1 %, and grain yield at the 5% probability levels. The highest bean seed yield with an average of 5461.6 kg.ha-1 and lowest weed dry weight with an average of 345.9 kg.ha-1 were related to pre-emergence herbicide and cultivation with a dose of 1 liter per hectare treatment. The difference between full and reduced doses of chemical weed control was non-significant. It could be concluded that integrated mechanical and chemical weed control not only may increase seed yield but also reduce, environmental hazards.

  12. Using genetically modified tomato crop plants with purple leaves for absolute weed/crop classification.

    Science.gov (United States)

    Lati, Ran N; Filin, Sagi; Aly, Radi; Lande, Tal; Levin, Ilan; Eizenberg, Hanan

    2014-07-01

    Weed/crop classification is considered the main problem in developing precise weed-management methodologies, because both crops and weeds share similar hues. Great effort has been invested in the development of classification models, most based on expensive sensors and complicated algorithms. However, satisfactory results are not consistently obtained due to imaging conditions in the field. We report on an innovative approach that combines advances in genetic engineering and robust image-processing methods to detect weeds and distinguish them from crop plants by manipulating the crop's leaf color. We demonstrate this on genetically modified tomato (germplasm AN-113) which expresses a purple leaf color. An autonomous weed/crop classification is performed using an invariant-hue transformation that is applied to images acquired by a standard consumer camera (visible wavelength) and handles variations in illumination intensities. The integration of these methodologies is simple and effective, and classification results were accurate and stable under a wide range of imaging conditions. Using this approach, we simplify the most complicated stage in image-based weed/crop classification models. © 2013 Society of Chemical Industry.

  13. Weed spectrum and selectivity of tembotrione under varying environmental conditions

    Directory of Open Access Journals (Sweden)

    Gatzweiler, Elmar

    2012-03-01

    Full Text Available Tembotrione is a novel HPPD maize herbicide effective against a wide range of broadleaf and grass weeds. Some characteristics of this compound are described in this paper linking weed and crop responses following tembotrione applications to environmental parameters or use conditions. The activity of HPPD herbicides is very much dependant on the availability of light. Increasing illumination intensities following application augmented the activity levels of several comparable HPPD compounds in a growth chamber experiment. Tembotrione was shown to be more efficacious at low and high illumination intensities compared to standard herbicides applied at the same rate. At the high intensity, tembotrione retained its high efficacy from two up to four weeks after application showing a rapid and strong herbicidal activity. The activity following post-emergent treatments of tembotrione against broadleaf weeds was influenced by soil characteristics such as soil texture and organic matter content in a glasshouse test. The level of weed suppression clearly declined stronger on heavier soils than on lighter soils at a rather low application rate of 12.5 g a.i./ha and lower. This is a clear indication of residual efficacy of tembotrione. The selectivity of tembotrione was tested on numerous maize varieties following post-emergent treatment with tembotrione alone or in mixture with the safener isoxadifen-ethyl under field conditions in Germany in comparison to a standard herbicide. The level of crop phytotoxicity tended to increase in the following order: Tembotrione plus safener, standard herbicide to tembotrione alone. Only the mixture of tembotrione with safener did not cause significant adverse effects on maize. Another field experiment in the USA examined crop phytotoxicity using one maize variety in a situation of infurrow soil insecticide treatment followed by a post-emergent application of tembotrione (plus/minus isoxadifen-ethyl and standard herbicides

  14. Favorable fragmentation: river reservoirs can impede downstream expansion of riparian weeds.

    Science.gov (United States)

    Rood, Stewart B; Braatne, Jeffrey H; Goater, Lori A

    2010-09-01

    River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and

  15. The effect of species, planting date, and management of cover crops on weed community in hybrid sunflower (Helianthus annuus

    Directory of Open Access Journals (Sweden)

    M. Bolandi Amoughein

    2016-02-01

    .: Results of the study indicated that the interaction between cover crop and planting date on density and dry weight of bindweed was significant at probability level of 5% and 1%, respectively. The best condition of reduced density of bindweed was related to the time of using rye cover crop where reduced Field bindweed density to 64% compared to control (without cover crop, no weeding. Date of simultaneous planting of cover crop, reduced bindweed density from mean 15/7% plant.m-2 to 11/62 plant.m-2, compared to 45 days after sunflower planting. Hasannejad and Alizadeh, (2005 reported that rye significantly controlled the weeds of redroot pigweed, common lambsquarters, knotgrass, russian thistle and field bindweed compared to controls with no cover crop. All three cover crops had significant effect on reducing the dry weight of bindweed. Cover crops showed the potential to reduce density and total dry weight of weeds compared to no control weeds and increase the plant yield. In a study, the density and dry weight of field bindweed in treated living rye and dead rye reduced 100% and 85% respectively (Samadani & Montazeri, 2009. Density and dry weightof Pale bugloss (Anchusa italica Retz: The interaction (cover crop × planting date on pale bugloss density and dry weight was meaningful in probability level of 1%.All three cover crops with simultaneous planting date showed lowest density of pale bugloss. Rye with proper ground cover in the beginning of season, and due to the long-term preservation of residues in the ground level, inhibited germination and growth of weeds for longer times. Results of the studies by (Abdollahyan Noghaby et al., 2011 on sugar beet showed that the effects of planting cover crops of triticale, wheat, rye and barley, between rows where sugar beet planted, to control weeds population would be the same as when herbicide used to control these weeds. Density and dry weight ofRussian thistle (Salsola kali L.: Results indicated that the interaction effect

  16. Chemical Weed Control Increases Survival and Growth in Hardwood Plantings

    Science.gov (United States)

    Gayne G. Erdmann

    1967-01-01

    In a plantation of four hardwood species on a silt loam soil planted to 1-0 stock, 4 pounds of active atrazine or simazine controlled weeds effectively without injuring the trees. Chemical weed control was better on plowed and disked ground than on unprepared ground. Yellow-poplar and white ash grew faster on prepared ground. Black walnut and red oak did not respond...

  17. Weed mapping in early-season maize fields using object-based analysis of unmanned aerial vehicle (UAV) images.

    Science.gov (United States)

    Peña, José Manuel; Torres-Sánchez, Jorge; de Castro, Ana Isabel; Kelly, Maggi; López-Granados, Francisca

    2013-01-01

    The use of remote imagery captured by unmanned aerial vehicles (UAV) has tremendous potential for designing detailed site-specific weed control treatments in early post-emergence, which have not possible previously with conventional airborne or satellite images. A robust and entirely automatic object-based image analysis (OBIA) procedure was developed on a series of UAV images using a six-band multispectral camera (visible and near-infrared range) with the ultimate objective of generating a weed map in an experimental maize field in Spain. The OBIA procedure combines several contextual, hierarchical and object-based features and consists of three consecutive phases: 1) classification of crop rows by application of a dynamic and auto-adaptive classification approach, 2) discrimination of crops and weeds on the basis of their relative positions with reference to the crop rows, and 3) generation of a weed infestation map in a grid structure. The estimation of weed coverage from the image analysis yielded satisfactory results. The relationship of estimated versus observed weed densities had a coefficient of determination of r(2)=0.89 and a root mean square error of 0.02. A map of three categories of weed coverage was produced with 86% of overall accuracy. In the experimental field, the area free of weeds was 23%, and the area with low weed coverage (weeds) was 47%, which indicated a high potential for reducing herbicide application or other weed operations. The OBIA procedure computes multiple data and statistics derived from the classification outputs, which permits calculation of herbicide requirements and estimation of the overall cost of weed management operations in advance.

  18. Periods of weed interference in maize crops cultivated in the first and second cycles

    Directory of Open Access Journals (Sweden)

    Caio Ferraz de Campos

    2016-10-01

    Full Text Available The interference of weeds in maize production may be reflected in grain yield losses that vary as a function of the density, stage and degree of aggressiveness of the species present. In the agricultural ecosystem, crops and weeds demand light, water, nutrients and space, which are frequently not available in sufficient quantities, leading to competition. The aim of this work was to determine the period of interference of weed plants, in particular of naked crabgrass (Digitaria nuda on maize crop in the first and second harvest. The treatments were defined as increasing periods of coexistence and increasing control of weed community (7, 14, 21, 28, 35, 42, 49, and 56 days, two more controls, a control including one with weed control until the end of the culture cycle and another with coexistence until the harvest. For each period, were evaluated the stand of maize plants, length of ear, number of grains per row, number of rows per ear, cob, 100-grain weight, and grain productivity. The data obtained were subjected to analysis of variance using the F test, with average treatments compared using Tukey’s test at 5% probability. Crop productivity was evaluated by means of regressions, the critical periods of interference were estimated. The critical timing of weed removal was 25 days for both harvests. The critical weed free period was 54 and 27 days for the first and second harvest respectively. For the conditions of the first and second harvest, the critical period of weed control was of 29 and 2 days respectively.

  19. Weed species composition and distribution pattern in the maize crop under the influence of edaphic factors and farming practices: A case study from Mardan, Pakistan.

    Science.gov (United States)

    Ahmad, Zeeshan; Khan, Shujaul Mulk; Abd Allah, Elsayed Fathi; Alqarawi, Abdulaziz Abdullah; Hashem, Abeer

    2016-11-01

    Weeds are unwanted plant species growing in ordinary environment. In nature there are a total of 8000 weed species out of which 250 are important for agriculture world. The present study was carried out on weed species composition and distribution pattern with special reference to edaphic factor and farming practices in maize crop of District Mardan during the months of August and September, 2014. Quadrates methods were used to assess weed species distribution in relation to edaphic factor and farming practices. Phytosociological attributes such as frequency, relative frequency, density, relative density and Importance Values were measured by placing 9 quadrates (1 × 1 m 2 ) randomly in each field. Initial results showed that the study area has 29 diverse weed species belonging to 27 genera and 15 families distributed in 585 quadrats. Presence and absence data sheet of 29 weed species and 65 fields were analyzed through PC-ORD version 5. Cluster and Two Way Cluster Analyses initiated four different weed communities with significant indicator species and with respect to underlying environmental variables using data attribute plots. Canonical Correspondence Analyses (CCA) of CANOCO software version 4.5 was used to assess the environmental gradients of weed species. It is concluded that among all the edaphic factors the strongest variables were higher concentration of potassium, organic matter and sandy nature of soil. CCA plots of both weed species and sampled fields based on questionnaire data concluded the farming practices such as application of fertilizers, irrigation and chemical spray were the main factors in determination of weed communities.

  20. Efficacy evaluation of selected herbicides on weed control and productivity evaluation of Bt cotton in Punjab.

    Science.gov (United States)

    Singh, Kulvir; Rathore, Pankaj

    2015-07-01

    Field experiments were conducted during Kharif 2012 and 2013 to evaluate the efficacy of different herbicides for weed management in cotton. Highest seed cotton yield (3537.3 kg ha(-1)) was recorded in weed free plots followed by pendimethalin @1.0 kg a.i ha(-1) as Pre.em.+quizalofopethyl @50 g a.i ha(-1) post-em at 2-4 weed leaf stage + one hoeing (3318.9 kg ha") owing to improved number of bolls per plant and boll weight. Statistically least yield was recorded underweedy check (1435.4 kg ha(-1)). Application of pyrithiobac sodium could not express any visible toxic effect on crop indicating its selectivity for cotton, although none of the tested new chemicals i.e., pyrithiobac sodium@ 62.5g a.i ha(-1) and quizalofopethyl @50g a.i ha(-1) when applied alone could not outperform the existing recommended chemicals for weed management. Yield losses to the extent of 6.2-59.4% were recorded due to weed competition. Weed control efficiency (WCE) was highest under weed free check (86.8%) followed by pendimethalin @1.0 kg a.i ha(-1) as Pre. em.+quizalofopethyl @50g a.i ha(-1), at 2-4 weed leaf stage + one hoeing (73.7%), whereas minimum values were for weedy check (24.7%). Though net returns (r94660 ha(-1)) were highest for weed free check but higher B:C ratio (2:11) was observed for pendimethalin @1.0 kg a.i ha(-1) as Pre em.+quizalofopethyl @50 g a.i ha(-1) post-em at 2-4 weed leaf stage+one hoeing. Therefore, for reasons such as labor shortage besides their timely availability, using these herbicides in combination with cultural practices could be the practical solution foreconomically efficient and effective weed management.