WorldWideScience

Sample records for factors influencing soil

  1. Study on the influence factors about the soil radon measurement

    International Nuclear Information System (INIS)

    Wu Zixiang; Liu Yanbin; Jia Yuxin; Mai Weiji; Liu Xiaolian; Yang Yuhua

    2006-01-01

    Objective: To explore relevant factors about the soil radon measurement and provide gist of formulating correct measure method by studying the way of the soil radon measurement. Methods: Deflation-ionization room standard is adopted. Results: The concentration of soil radon becomes higher with the sample's volume added, it also augmented with the measure depth increased in certain degree; The concentration of soil radon changes little when sample's depth is above 60 cm; The time of deflation has no obvious influence on the concentration of soil radon, but microwave show serious effect on it; The results will be lowered when the desiccant is humidified, raining has the same affection on it; Plant has some impact on it. Conclusion: The measured results will be affected by microwave, oscillate and plant. Sample's volume and depth, soil's humidity can influence it too. The result's veracity can be guaranteed by choosing appropriate sample and measure condition. (authors)

  2. Soil sealing degree as factor influencing urban soil contamination with polycyclic aromatic hydrocarbons (PAHs

    Directory of Open Access Journals (Sweden)

    Mendyk Łukasz

    2016-03-01

    Full Text Available The objective of the study was to determine role of soil sealing degree as the factor influencing soil contamination with polycyclic aromatic hydrocarbons (PAHs. The study area included four sampling sites located within the administrative boundaries of the Toruń city, Poland. Sampling procedure involved preparing soil pits representing three examples of soil sealing at each site: non-sealed soil as a control one (I and two degrees of soil sealing: semi-pervious surface (II and totally impervious surface (III. Together with basic properties defined with standard procedures (particle size distribution, pH, LOI, content of carbonates content of selected PAHs was determined by dichloromethane extraction using gas chromatography with mass spectrometric detection (GC-MS. Obtained results show that urban soils in the city of Toruń are contaminated with polycyclic aromatic hydrocarbons. Soil sealing degree has a strong influence on the soil contamination with polycyclic aromatic hydrocarbons. Totally sealed soils are better preserved from atmospheric pollution including PAHs. Combustion of grass/wood/coal was the main source of determined PAHs content in examined soils.

  3. Physical and chemical factors influencing radionuclide behaviour in arable soils

    International Nuclear Information System (INIS)

    Rauret, G.; Vidal, M.; Alexakhin, R.M.; Kruglov, S.V.; Cremers, A.; Wauters, J.; Valcke, E.; Ivanov, Y.

    1996-01-01

    Soil-to-plant transfer of radionuclides integrates plant physiological and soil chemical aspects. Therefore, it is necessary to study the factors affecting the equilibrium of the radionuclides between solid and soil solution phases. Desorption and adsorption studies were applied to the podsolic and peat soils considered in the ECP-2 project. In the desorption approach, both sequential extraction and 'infinite bath' techniques were used. In the adsorption approach, efforts were directed at predicting Cs and Sr-K D on the basis of soil properties and soil solution composition. Desorption approach predicts time-dynamics of transfer with time but it is un sufficient for comparatively predicting transfer. Adsorption studies informs about which are the key factors affecting radionuclide transfer. For Sr, availability depends on the CEC and on the concentration of the Ca + Mg in the soil solution. For Cs, availability is mainly dependent on the partitioning between FES -frayed edge sites-, which are highly specific and REC -regular exchange complex-, with low selectivity for Cs. Moreover, availability depends on the K and NH 4 , levels in the soil solution and fixation properties of the soil. Considering these factors, the calculation of the in situ K D values helps to predict the relative transfer of radionuclides. The calculation of the K D of the materials that could be used as countermeasures could permit the prediction of its suitability to decrease transfer and therefore to help in producing cleaner agricultural products

  4. Spatial pattern of heavy metals accumulation risk in urban soils of Beijing and its influencing factors

    International Nuclear Information System (INIS)

    Liu, Rui; Wang, Meie; Chen, Weiping; Peng, Chi

    2016-01-01

    Accumulations of heavy metals in urban soils are highly spatial heterogeneity and affected by multiple factors including soil properties, land use and pattern, population and climatic conditions. We studied accumulation risks of Cd, Cu, Pb and Zn in unban soils of Beijing and their influencing based on the regression tree analysis and a GIS-based overlay model. Result shows that Zinc causes the most extensive soil pollution and Cu result in the most acute soil pollution. The soil's organic carbon content and CEC and population growth are the most significant factors affecting heavy metal accumulation. Other influence factors in land use pattern, urban landscape, and wind speed also contributed, but less pronounced. The soils in areas with higher degree of urbanization and surrounded by intense vehicular traffics have higher accumulation risk of Cd, Cu, Pb, and Zn. - Highlights: • Zn accumulations were the most extensive and Cu accumulations were the most acute. • Accumulations of Cd, Cu, Pb and Zn in urban soils were caused by different sets of influence factors. • Soil's organic carbon content and CEC and population growth were the most significant factors. • Accumulation risks were highly related with urbanization level and human activities. - A combined approach of employing geographical information systems and regression tree analyses identify the potential risks of accumulation Cd, Cu, Pb, and Zn in urban soils according to soil properties, urban land use patterns, urban landscape, demographics, and microclimatic conditions.

  5. Investigation of features in radon soil dynamics and search for influencing factors

    Science.gov (United States)

    Yakovlev, Grigorii; Cherepnev, Maxim; Nagorskiy, Petr; Yakovleva, Valentina

    2018-03-01

    The features in radon soil dynamics at two depths were investigated and the main influencing factors were revealed. The monitoring of radon volumetric activity in soil air was performed at experimental site of Tomsk Observatory of Radioactivity and Ionizing Radiation with using radon radiometers and scintillation detectors of alpha-radiation with 10 min sampling frequency. The detectors were installed into boreholes of 0.5 and 1 m depths. The analysis of the soil radon monitoring data has allowed revealing some dependencies at daily and annual scales and main influencing factors. In periods with clearly defined daily radon variations in the soil were revealed the next: 1) amplitude of the daily variations of the soil radon volumetric activity damps with the depth, that is related with the influence of convective fluxes in the soil; 2) temporal shift between times of occurrence of radon volumetric activity maximum (or minimum) values at 0.5 m and 1 m depths can reach 3 hours. In seasonal dynamics of the soil radon the following dependences were found: 1) maximal values are observed in winter, but minimal - in summer; 2) spring periods of snow melting are accompanied by anomaly increasing of radon volumetric activity in the soil up to about 3 times. The main influencing factors are atmospheric precipitations, temperature gradient in the soil and the state of upper soil layer.

  6. The influence of site factors on nitrogen mineralization in forest soils ...

    African Journals Online (AJOL)

    The influence of site factors on nitrogen mineralization in forest soils of the ... on N mineralization, as well as the effect of N mineralization on forest productivity. ... of the natural log of mean annual temperature, geological substrate and total N ...

  7. Factors influencing adoption of soil and water conservation measures in southern Mali

    NARCIS (Netherlands)

    Bodnar, F.; Graaff, de J.

    2003-01-01

    A soil and water conservation (SWC) extension programme, promoting erosion control measures and soil fertility measures, has been going on in southern Mali since 1986. Five factors that influence farmer adoption of SWC measures were analysed: land pressure, cotton-growing area, possession of

  8. Factors of influencing dissolved organic carbon stabilization in two cambic forest soils with contrasting soil-forming processes

    Science.gov (United States)

    Kawasaki, M.; Ohte, N.; Asano, Y.; Uchida, T.; Kabeya, N.; Kim, S.

    2004-05-01

    Stabilization of Dissolved Organic Carbon (DOC) in forest soil is a major process of soil organic carbon formation. However, the factors influencing DOC stabilization are poorly understood. To clarify the factors that affect the stabilization of DOC in forest soil mantle, we measured DOC concentrations and soil properties which were DOC adsorption efficiency at two adjacent cambic forest soils with contrasting forest management histories in Tanakami Mountains, central Japan. Matsuzawa was devastated about 1,200 years ago by excessive timber use and remained denuded for a long period. Hillside restoration and reforestation work have been carried out over the last 100 years and soil loss has been reduced. Fudoji is covered with undisturbed forest (mixed stands of cypress and oaks) with developed forest soils (more than 2,600 years old). There was no apparent seasonal variation in DOC concentration in the soil solution in either catchment. In addition, there were no significant relationships between the DOC concentration, soil temperature, and new water ratio. These results indicate that temporal variation in biological activity and rainfall-runoff process have little effect on temporal variation in DOC. The vertical variation in the DOC adsorption efficiency and DOC concentration differed between Matsuzawa and Fudoji, and the highest DOC removal rate occurred at the lowest DOC adsorption efficiency in the 0 to 10-cm soil layer at Fudoji. These results suggest that DOC removal rate is independent of DOC adsorption efficiency. Below 60 cm soil depth, DOC fluxes were constant and dissolved organic Al concentrations were little or zero in either catchment. These results suggest that abiotic precipitation of DOC is a major mechanism for stabilization of DOC. Therefore, DOC content which is able to form metal complexes may be the most important factor of influencing DOC stabilization in cambic forest soil.

  9. The Influence of Soil Chemical Factors on In Situ Bioremediation of Soil Contamination

    Energy Technology Data Exchange (ETDEWEB)

    Breedveld, Gijs D.

    1997-12-31

    Mineral oil is the major energy source in Western society. Production, transport and distribution of oil and oil products cause serious contamination problems of water, air and soil. The present thesis studies the natural biodegradation processes in the soil environment which can remove contamination by oil products and creosote. The main physical/chemical processes determining the distribution of organic contaminants between the soil solid, aqueous and vapour phase are discussed. Then a short introduction to soil microbiology and environmental factors important for biodegradation is given. There is a discussion of engineered and natural bioremediation methods and the problems related to scaling up laboratory experiments to field scale remediation. Bioremediation will seldom remove the contaminants completely; a residue remains. Factors affecting the level of residual contamination and the consequences for contaminant availability are discussed. Finally, the main findings of the work are summarized and recommendations for further research are given. 111 refs., 41 figs., 19 tabs.

  10. Soil moisture and biogeochemical factors influence the distribution of annual Bromus species

    Science.gov (United States)

    Jayne Belnap; John M. Stark; Benjamin M. Rau; Edith B. Allen; Susan Phillips

    2016-01-01

    Abiotic factors have a strong influence on where annual Bromus species are found. At the large regional scale, temperature and precipitation extremes determine the boundaries of Bromus occurrence. At the more local scale, soil characteristics and climate influence distribution, cover, and performance. In hot, dry, summer-rainfall-dominated deserts (Sonoran, Chihuahuan...

  11. Influences Factors of the Cadmium Removal by Magnetic Solid Chelator Powder(MSC in Soil

    Directory of Open Access Journals (Sweden)

    LIU Jun-long

    2017-12-01

    Full Text Available Pot experiments were conducted for the purpose of analyzing the influencing effects for the magnetic solid chelator powder(MSC, magnetic solid chelator powder on removal of cadmium pollution in the soil. The influencing factors included straws,air drying,activation structural material, stirring time and repetition times, etc. The results showed that the straw addition in the soil decreased the removal efficiency of Cd. The different air drying degree in the soil also had the effect of MSC. The air drying in the soil affected the results more by comparison with the straws. When stirring time was 40 min, the removal rate of Cd was 22.67% and achieved the best removal efficiency. With the increasing of stirring time, the effect of MSC on Cd removal increased first, then decreased. Drying MSC material lost the effect of Cd removal in the soil. After activation(soaking in water for 12 h, MSC material could remov Cd in the soil once again. MSC material had removal and remediation effects on soil Cd, the removal effects depended on soil properties, material properties and operation process and other factors. The research of MSC materials in soil remediation had important practical significance.

  12. The Validation Of Influence Factors To DDT Concentration In Soil

    International Nuclear Information System (INIS)

    Kamal, Zainul; Poernomo, Herry

    2000-01-01

    Determination concentration of DDT in humidified land's and rising intensity has been done. The amount of natural soil was filled in poliethylene tube, and the amount of humadified soil was filled in order poliethylene tube. The solution of DDT-C sub.14 with volume of 10 ml and activity of 10 muCi was increased in those tube respectively, the latter it was resident for many time under shine. Sample of soil was took first week to sixthweek, it was crushed to reach homogenous, then it was counted by liquid scintillation counter. The experiment result indicated that the DDT content in the unilluminated soil for 1 week is < 0.1 ppb, for 2 week is 0.19 n 0.01 ppb, for 3 week is 1.95 n 0.32 ppb, for 4 week is 14.07 n 0.14 ppb, for 5 week is 3.67 n 0.21 ppb and for 6 week is 2.28 n 0.09 ppb. The DDT content in the humidified soil without sun illumination for 1 week is 0.25 n 0.07 ppb, for 2 week is 6.34 n 0.19 ppb, for 3 week is 9.33 n 0.80 ppb, for 4 week is 12.36 n 0.17 ppb, for 5 week is 4.58 n 0.15 ppb and for 6 week is 2.01 n 0.55 ppb. The DDT content in the natural soil illuminated by VIS for 1 week is 0.74 n 0.08 ppb, for 2 week is 7.48 n 0.14 ppb, for 3 week is 4.06 n 0.28 ppb, for 4 week is 13.16 n 0.20 ppb, for 5 week is 5.00 n 0.70 ppb and for 6 week is 2.03 n 0.03 ppb

  13. Factors influencing the chemical extractability of 241Am from a contaminated soil

    International Nuclear Information System (INIS)

    Nishita, H.; Hamilton, M.

    1976-01-01

    Factors influencing the extractability of 241 Am from an artificially contaminated soil were investigated. This was done with an equilibrium batch technique using CH 3 COOH-NH 4 OH and HNO 3 -NaOH extracting systems. The influence of several soil components was determined indirectly by selectively removing them from the soil. The effect of water- and HCl-soluble salts and organic matter on 241 Am extractability was small. The most marked effect was due to the soil organic fraction that was not water- or HCl-soluble. This organic fraction was influential under both low and high pH conditions, but its influence was particularly marked under low pH conditions. The free iron-oxides had an appreciable effect under low pH conditions, but no observable effect in the high pH range. Though to a lesser extent, the free silica and alumina, amorphous alumino-silicate, and possibly residual organic matter also showed some influence. These results provide some implications on the conditions that influence the movement of 241 Am in soils and its availability to plants. A review of the literature on the behavior of Am in soils is included

  14. Influence of the soil sealing on the geoaccumulation index of heavy metals and various pollution factors.

    Science.gov (United States)

    Charzyński, Przemysław; Plak, Andrzej; Hanaka, Agnieszka

    2017-02-01

    Soil sealing belongs to the most destructive and damaging processes to the soil environment. Soil sealing interrupts or greatly restricts the exchange of matter and energy between the biosphere, hydrosphere, and atmosphere and the soil environment. The aim of this study was to compare the content of heavy metals (Cd, Cr, Cu, Hg, Fe, Ni, Pb, Zn) of Ekranic Technosols by applying indicators such as geoaccumulation index (I geo ), enrichment factor (EF), and pollution load index (PLI), which allowed to determine quantitatively the impact of the soil sealing degree on the content of heavy metals and to distinguish natural from anthropogenic sources of origin of heavy metals. In general, 42 soils from different parts of the city of Toruń (NW Poland) were sampled and divided into three groups according to the degree of soil sealing: completely sealed with asphalt or concrete (A), semi-permeable (partially sealed with cobblestones and concrete paving slabs (B)), and reference (non-sealed) (C). The results indicate that the artificial sealing in urban areas slightly affects the content of heavy metals in soils. However, based on PLI, I geo , and EF, it was found that the sealing has influence on soil properties and unsealed soil is the most exposed to the accumulation of pollutants.

  15. Polycyclic aromatic hydrocarbons in soils from the Tibetan Plateau, China: distribution and influence of environmental factors.

    Science.gov (United States)

    Wang, Shuang; Ni, Hong-Gang; Sun, Jian-Lin; Jing, Xin; He, Jin-Sheng; Zeng, Hui

    2013-03-01

    Thirty four sampling sites along an elevation transect in the Tibetan Plateau region were chosen. Soil cores were divided into several layers and a total of 175 horizon soil samples were collected from July to September 2011, for determination of polycyclic aromatic hydrocarbons (PAHs). The measured PAHs concentration in surface soils was 56.26 ± 45.84 ng g(-1), and the low molecular weight PAHs (2-3 rings) predominated, accounting for 48% and 35%. We analyzed the spatial (altitudinal and vertical) distribution of PAHs in soil, and explored the influence of related environmental factors. Total organic carbon (TOC) showed a controlling influence on the distribution of PAHs. PAH concentrations declined with soil depth, and the composition patterns of PAHs along soil depth indicated that the heavy PAHs tended to remain in the upper layers (0-10 cm), while the light fractions were transported downward more easily. PAHs inventories (8.77-57.92 mg m(-2)) for soil cores increased with mean annual precipitation, while the topsoil concentrations decreased with it. This implies that an increase in precipitation could transfer more PAHs from the atmosphere to the soil and further transport PAHs from the topsoil to deeper layers.

  16. Geologic and edaphic factors influencing susceptibility of forest soils to environmental change

    Science.gov (United States)

    Scott W. Bailey

    2000-01-01

    There is great diversity in the structure and function of the northern forest across the 20-state portion of the United States considered in this book. The interplay of many factors accounts for the mosaic of ecological regimes across the region. In particular, climate, physiography, geology, and soils influence dominance and distribution of vegetation communities...

  17. Intrinsic factors of Peltigera lichens influence the structure of the associated soil bacterial microbiota.

    Science.gov (United States)

    Leiva, Diego; Clavero-León, Claudia; Carú, Margarita; Orlando, Julieta

    2016-11-01

    Definition of lichens has evolved from bi(tri)partite associations to multi-species symbioses, where bacteria would play essential roles. Besides, although soil bacterial communities are known to be affected by edaphic factors, when lichens grow upon them these could become less preponderant. We hypothesized that the structure of both the lichen microbiota and the microbiota in the soil underneath lichens is shaped by lichen intrinsic and extrinsic factors. In this work, intrinsic factors corresponded to mycobiont and cyanobiont identities of Peltigera lichens, metabolite diversity and phenoloxidase activity and extrinsic factors involved the site of the forest where lichens grow. Likewise, the genetic and metabolic structure of the lichen and soil bacterial communities were analyzed by fingerprinting. Among the results, metabolite diversity was inversely related to the genetic structure of bacterial communities of lichens and soils, highlighting the far-reaching effect of these substances; while phenoloxidase activity was inversely related to the metabolic structure only of the lichen bacterial microbiota, presuming a more limited effect of the products of these enzymes. Soil bacterial microbiota was different depending on the site and, strikingly, according to the cyanobiont present in the lichen over them, which could indicate an influence of the photobiont metabolism on the availability of soil nutrients. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. The influence of use-related, environmental, and managerial factors on soil loss from recreational trails

    Science.gov (United States)

    Olive, Nathaniel D.; Marion, Jeffrey L.

    2009-01-01

    Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered a significant and irreversible form of trail impact. This research investigated the influence of several use-related, environmental, and managerial factors on soil loss on recreational trails and roads at Big South Fork National River and Recreation Area, a unit of the U.S. National Park Service. Regression modeling revealed that trail position, trail slope alignment angle, grade, water drainage, and type of use are significant determinants of soil loss. The introduction of individual and groups of variables into a series of regression models provides improved understanding and insights regarding the relative influence of these variables, informing the selection of more effective trail management actions. Study results suggest that trail erosion can be minimized by avoiding “fall-line” alignments, steep grades, and valley-bottom alignments near streams, installing and maintaining adequate densities of tread drainage features, applying gravel to harden treads, and reducing horse and all-terrain vehicle use or restricting them to more resistant routes.This research also sought to develop a more efficient Variable Cross-Sectional Area method for assessing soil loss on trails. This method permitted incorporation of CSA measures in a representative sampling scheme applied to a large (24%) sample of the park's 526 km trail system. The variety of soil loss measures derived from the Variable CSA method, including extrapolated trail-wide soil loss estimates, permit an objective quantification of soil erosion on recreational trails and roads. Such data support relational analyses to increase understanding of trail degradation, and long

  19. The influence of use-related, environmental, and managerial factors on soil loss from recreational trails.

    Science.gov (United States)

    Olive, Nathaniel D; Marion, Jeffrey L

    2009-03-01

    Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered a significant and irreversible form of trail impact. This research investigated the influence of several use-related, environmental, and managerial factors on soil loss on recreational trails and roads at Big South Fork National River and Recreation Area, a unit of the U.S. National Park Service. Regression modeling revealed that trail position, trail slope alignment angle, grade, water drainage, and type of use are significant determinants of soil loss. The introduction of individual and groups of variables into a series of regression models provides improved understanding and insights regarding the relative influence of these variables, informing the selection of more effective trail management actions. Study results suggest that trail erosion can be minimized by avoiding "fall-line" alignments, steep grades, and valley-bottom alignments near streams, installing and maintaining adequate densities of tread drainage features, applying gravel to harden treads, and reducing horse and all-terrain vehicle use or restricting them to more resistant routes. This research also sought to develop a more efficient Variable Cross-Sectional Area method for assessing soil loss on trails. This method permitted incorporation of CSA measures in a representative sampling scheme applied to a large (24%) sample of the park's 526 km trail system. The variety of soil loss measures derived from the Variable CSA method, including extrapolated trail-wide soil loss estimates, permit an objective quantification of soil erosion on recreational trails and roads. Such data support relational analyses to increase understanding of trail degradation, and long-term monitoring of

  20. Identification of factors influencing the restoration of cyanobacteria-dominated biological soil crusts.

    Directory of Open Access Journals (Sweden)

    Chongfeng Bu

    Full Text Available Biological soil crusts (BSCs cover >35% of the Earth's land area and contribute to important ecological functions in arid and semiarid ecosystems, including erosion reduction, hydrological cycling, and nutrient cycling. Artificial rapid cultivation of BSCs can provide a novel alternative to traditional biological methods for controlling soil and water loss such as the planting of trees, shrubs, and grasses. At present, little is known regarding the cultivation of BSCs in the field due to lack of knowledge regarding the influencing factors that control BSCs growth. Thus, we determined the effects of various environmental factors (shade; watering; N, P, K, and Ca concentrations on the growth of cyanobacteria-dominated BSCs from the Sonoran Desert in the southwestern United States. The soil surface changes and chlorophyll a concentrations were used as proxies of BSC growth and development. After 4 months, five factors were found to impact BSC growth with the following order of importance: NH4NO3 ≈ watering frequency>shading>CaCO3 ≈ KH2PO4. The soil water content was the primary positive factor affecting BSC growth, and BSCs that were watered every 5 days harbored greater biomass than those watered every 10 days. Groups that received NH4NO3 consistently exhibited poor growth, suggesting that fixed N amendment may suppress BSC growth. The effect of shading on the BSC biomass was inconsistent and depended on many factors including the soil water content and availability of nutrients. KH2PO4 and CaCO3 had nonsignificant effects on BSC growth. Collectively, our results indicate that the rapid restoration of BSCs can be controlled and realized by artificial "broadcasting" cultivation through the optimization of environmental factors.

  1. Influence of multiple factors on plant local adaptation: soil type and folivore effects in Ruellia nudiflora (Acanthaceae)

    OpenAIRE

    Ortegón-Campos, I.; Abdala-Roberts, Luis; Parra-Tabla, Víctor; Cervera, J. Carlos; Marrufo-Zapata, Denis; Herrera, Carlos M.

    2011-01-01

    Different environmental factors can have contrasting effects on the extent of plant local adaptation (LA). Here we evaluate the influence of folivory and soil type on LA in Ruellia nudiflora by performing reciprocal transplants at two sites in Yucatan (Mexico) while controlling for soil source and folivory level. Soil samples were collected at each site and half of the plants of each source at each site were grown with one soil source and half with the other. After transplanting, we reduced f...

  2. Soil Forming Factors

    Science.gov (United States)

    It! What is Soil? Chip Off the Old Block Soil Forming Factors Matters of Life and Death Underneath It All Wise Choices A World of Soils Soil Forming Factors 2 A Top to Bottom Guide 3 Making a Soil Monolith 4 Soil Orders 5 State Soil Monoliths 6 Where in the Soil World Are You? >> A Top to

  3. Spatial patterns of soil pH and the factors that influence them in plantation forests of northern China

    Science.gov (United States)

    Hong, Songbai; Liu, Yongwen; Piao, Shilong

    2017-04-01

    Climate and anthropogenic activities such as afforestation and nitrogen deposition all impact soil pH. Understanding the spatial pattern of soil pH and the factors that influence it can provide basic information for generating appropriate strategies for soil resource management and protection, especially in light of increasing anthropogenic influences and climate change. In this study, we investigated the spatial and vertical pattern of soil pH and evaluated the influence of climate and nitrogen deposition using 1647 soil profiles 1 meter in depth from 549 plots in plantation forests of northern China. We found that soil pH decreased from the southwest to the northeast in the study region and had a similar spatial pattern before and after afforestation. Furthermore, our results show that climate and nitrogen deposition fundamentally influence the pattern of soil pH. Specifically, increasing precipitation significantly decreased soil pH (with a mean rate of 0.3 for every 100 mm rainfall, ppH (0.13 for every degree centigrade, ppH (ppH directly and indirectly through climate-plant-soil interactions. As the risks from both climate change and nitrogen deposition increase, there is an urgent need to further understanding of soil pH dynamics and to develop informed policies to protect soil resources.

  4. Distribution of Soil Organic Carbon and the Influencing Factors in An Oasis Farmland Area

    Directory of Open Access Journals (Sweden)

    WANG Ze

    2014-08-01

    Full Text Available The soil organic carbon(SOC of a typical oasis farmland in middle part of Manasi county of Xinjiang was used as the research ob原 ject. Using remote sensing and lab analysis techniques, influences of soil texture, terrain, land uses, and crop types on SOC content of farmland were studied. Results showed that the SOC distribution in farmland of Manasi was mainly determined by comprehensive natural environmental factors. The SOC content decreased along with the increasing soil depth. For soil textures, the SOC content from high to low was clay loam>powder loam>silty loam. Slope direction had significantly positive correlations with SOC contents at 0~30 cm and 30~60 cm, while altitude and SOC content at 60~100 cm were significantly positive correlation. The SOC content of orchard was the highest, and the uncultivated land was the lowest under different land-use patterns. For different crop planting systems, the order of SOC content was corn field >wine grapes field>cotton field, and the difference was significant.

  5. Characterisation of the rhizoremediation of petroleum-contaminated soil: effect of different influencing factors

    Directory of Open Access Journals (Sweden)

    J. C. Tang

    2010-12-01

    Full Text Available Pilot experiments were conducted to analyse the effect of different environmental factors on the rhizoremediation of petroleum-contaminated soil. Different plant species (cotton, ryegrass, tall fescue and alfalfa, the addition of fertilizer, different concentrations of total petroleum hydrocarbons (TPH in the soil, bioaugmentation with effective microbial agents (EMA and plant growth-promoting rhizobacteria (PGPR and remediation time were tested as influencing factors during the bioremediation process of TPH. The results show that the remediation process can be enhanced by different plant species. The order of effectiveness of the plants was the following: tall fescue > ryegrass > alfalfa > cotton. The degradation rate of TPH increased with increased fertilizer addition, and a moderate urea level of 20 g N (Nitrogen/m2 was best for both plant growth and TPH remediation. A high TPH content is toxic to plant growth and inhibits the degradation of petroleum hydrocarbons. The results showed that a 5% TPH content gave the best degradation in soil planted with ryegrass. Bioaugmentation with different bacteria and PGPR yielded the following results for TPH degradation: cotton+EMA+PGPR > cotton+EMA > cotton+PGPR > cotton > control. Rapid degradation of TPH was found at the initial period of remediation caused by the activity of microorganisms. A continuous increase of degradation rate was found during the 30–90 days period followed by a slow increase during the 90–150 days period. These results suggest that rhizoremediation can be enhanced with the proper control of different influencing factors that affect both plant growth and microbial activity in the rhizosphere environment.

  6. Influence of natural and anthropogenic factors on the dynamics of CO2 emissions from chernozems soil

    Science.gov (United States)

    Syabruk, Olesia

    2017-04-01

    Twentieth century marked a significant expansion of agricultural production. Soil erosion caused by human activity, conversion of forests and grasslands to cropland, desertification, burning nutrient residues, drainage, excessive cultivation led to intense oxidation of soil carbon to the atmosphere and allocation of additional amounts of CO2. According to the UN Intergovernmental Panel on Climate Change, agriculture is one of the main sources of greenhouse gases emissions to the atmosphere. The thesis reveals main patterns of the impact of natural and anthropogenic factors on CO2 emissions in the chernozems typical and podzolized in a Left-bank Forest-Steppe of Ukraine, seasonal and annual dynamics. New provisions for conducting monitoring CO2 emissions from soil were developed by combining observations in natural and controlled conditions, which allows isolating the impact of hydrological, thermal and trophic factors. During the research, the methods for operational monitoring of emission of carbon losses were improved, using a portable infrared gas analyzer, which allows receiving information directly in the field. It was determined that the volumes of emission losses of carbon chernozems typical and podzolized Left-bank Forest-Steppe of Ukraine during the growing season are 480-910 kg/ha and can vary depending on the soil treatment ±( 4,0 - 6,0) % and fertilizer systems ± (3,8 - 7,1) %. The significant impact of long application of various fertilizer systems and soil treatment on the intensity of carbon dioxide emissions was investigated. It was found that most emission occurs in organic- mineral fertilizers systems with direct seeding. The seasonal dynamics of the potential capacity of the soil to produce CO2 were researched. Under identical conditions of humidity and temperature it has maximum in June and July and the gradual extinction of the autumn. It was determined that the intensity of the CO2 emission from the surface of chernozem fluctuates daily from

  7. Influence of environmental factors on the spatial distribution and diversity of forest soil in Latvia

    Directory of Open Access Journals (Sweden)

    Raimonds Kasparinskis

    2012-02-01

    Full Text Available This study was carried out to determine the spatial relationships between environmental factors (Quaternary deposits, topographical situation, land cover, forest site types, tree species, soil texture and soil groups, and their prefix qualifiers (according to the international Food and Agricultural Organization soil classification system World Reference Base for Soil Resources [FAO WRB]. The results show that it is possible to establish relationships between the distribution of environmental factors and soil groups by applying the generalized linear models in data statistical analysis, using the R 2.11.1 software for processing data from 113 sampling plots throughout the forest territory of Latvia.A very high diversity of soil groups in a relatively similar geological structure was revealed. For various reasons there is not always close relationship between the soil group, their prefix qualifiers and Quaternary deposits, as well as between forest site types, the dominant tree species and specific soil group and its prefix qualifiers. Close correlation was established between Quaternary deposits, forest site types, dominant tree species and soil groups within nutrient-poor sediments and very rich deposits containing free carbonates. No significant relationship was detected between the CORINE Land Cover 2005 classes, topographical situation and soil group.

  8. Available nitrogen is the key factor influencing soil microbial functional gene diversity in tropical rainforest.

    Science.gov (United States)

    Cong, Jing; Liu, Xueduan; Lu, Hui; Xu, Han; Li, Yide; Deng, Ye; Li, Diqiang; Zhang, Yuguang

    2015-08-20

    Tropical rainforests cover over 50% of all known plant and animal species and provide a variety of key resources and ecosystem services to humans, largely mediated by metabolic activities of soil microbial communities. A deep analysis of soil microbial communities and their roles in ecological processes would improve our understanding on biogeochemical elemental cycles. However, soil microbial functional gene diversity in tropical rainforests and causative factors remain unclear. GeoChip, contained almost all of the key functional genes related to biogeochemical cycles, could be used as a specific and sensitive tool for studying microbial gene diversity and metabolic potential. In this study, soil microbial functional gene diversity in tropical rainforest was analyzed by using GeoChip technology. Gene categories detected in the tropical rainforest soils were related to different biogeochemical processes, such as carbon (C), nitrogen (N) and phosphorus (P) cycling. The relative abundance of genes related to C and P cycling detected mostly derived from the cultured bacteria. C degradation gene categories for substrates ranging from labile C to recalcitrant C were all detected, and gene abundances involved in many recalcitrant C degradation gene categories were significantly (P rainforest. Soil available N could be the key factor in shaping the soil microbial functional gene structure and metabolic potential.

  9. [Investigation on prevalence of soil-transmitted nematode infections and influencing factors for children in southwest areas of China].

    Science.gov (United States)

    Wang, Xiao-Bing; Wang, Guo-Fei; Zhang, Lin-Xiu; Luo, Ren-Fu; Tian, Hong-Chun; Tang, Li-Na; Wang, Ju-Jun; Medina, Alexis; Wise, Paul; Rozelle, Scott

    2012-06-01

    To understand the infection status and main risk factors of soil-transmitted nematodes in southwest China so as to provide the evidence for making the control programs for soil-transmitted nematodiasis. The prevalence of soil-transmitted nematode infections was determined by Kato-Katz technique and influencing factors were surveyed by using a standardized questionnaire, and in part of the children, the examination of Enterobius vermicularis eggs was performed by using the cellophane swab method. The relationship between soil-transmitted nematode infections and influencing factors was analyzed by the multiple probit estimated method. A total of 1 707 children were examined, with a soil-transmitted nematode infection rate of 22.2%, the crowd infection rates ofAscaris lumbricoides, hookworm, and Trichuris trichiura were 16.0%, 3.8% and 6.6% respectively and 495 children were examined on Enterobius vermicularis eggs, with the infection rate of 5.1%. The results of probit estimated analysis suggested that the effects of 4 factors on soil-transmitted nematode infections were significant (all P values were less than 0.05), namely the number of sib, educational level of mother, drinking unboiled water and raising livestock and poultry. Among the factors above, the educational level of mother could reduce the probability of infection (ME = -0.074), while the number of sib, drinking unboiled water and raising livestock and poultry could increase the probability of the infections (with ME of 0.028, -0.112 and 0.080, respectively). Soil-transmitted nematode infection rates are still in a high level for children in southwest poor areas of China, with Ascaris lumbricoides as a priority. The changes of children's bad health habits, raising livestock and poultry habits, and implementing the health education about parasitic diseases in mothers would be of great significance for the prevention and control of soil-transmitted nematodiasis.

  10. Factors Influencing Access to Integrated Soil Fertility Management Information and Knowledge and Its Uptake among Smallholder Farmers in Zimbabwe

    Science.gov (United States)

    Gwandu, T.; Mtambanengwe, F.; Mapfumo, P.; Mashavave, T. C.; Chikowo, R.; Nezomba, H.

    2014-01-01

    Purpose: The study evaluated how farmer acquisition, sharing and use patterns of information and knowledge interact with different socioeconomic factors to influence integrated soil fertility management (ISFM) technology uptake. Design/methodology/approach: The study was conducted as part of an evaluation of field-based farmer learning approaches…

  11. Vertical distribution of soil saturated hydraulic conductivity and its influencing factors in a small karst catchment in Southwest China.

    Science.gov (United States)

    Fu, Tonggang; Chen, Hongsong; Zhang, Wei; Nie, Yunpeng; Wang, Kelin

    2015-03-01

    Saturated hydraulic conductivity (Ks) is one of the most important soil hydraulic parameters influencing hydrological processes. This paper aims to investigate the vertical distribution of Ks and to analyze its influencing factors in a small karst catchment in Southwest China. Ks was measured in 23 soil profiles for six soil horizons using a constant head method. These profiles were chosen in different topographical locations (upslope, downslope, and depression) and different land-use types (forestland, shrubland, shrub-grassland, and farmland). The influencing factors of Ks, including rock fragment content (RC), bulk density (BD), capillary porosity (CP), non-capillary porosity (NCP), and soil organic carbon (SOC), were analyzed by partial correlation analysis. The mean Ks value was higher in the entire profile in the upslope and downslope, but lower value, acting as a water-resisting layer, was found in the 10-20 cm soil depth in the depression. Higher mean Ks values were found in the soil profiles in the forestland, shrubland, and shrub-grassland, but lower in the farmland. These results indicated that saturation-excess runoff could occur primarily in the hillslopes but infiltration-excess runoff in the depression. Compared with other land-use types, surface runoff is more likely to occur in the farmlands. RC had higher correlation coefficients with Ks in all categories concerned except in the forestland and farmland with little or no rock fragments, indicating that RC was the dominant influencing factor of Ks. These results suggested that the vertical distributions of Ks and RC should be considered for hydrological modeling in karst areas.

  12. A cross-site comparison of factors influencing soil nitrification rates in northeastern USA forested watersheds

    Science.gov (United States)

    Ross, D.S.; Wemple, B.C.; Jamison, A.E.; Fredriksen, G.; Shanley, J.B.; Lawrence, G.B.; Bailey, S.W.; Campbell, J.L.

    2009-01-01

    Elevated N deposition is continuing on many forested landscapes around the world and our understanding of ecosystem response is incomplete. Soil processes, especially nitrification, are critical. Many studies of soil N transformations have focused on identifying relationships within a single watershed but these results are often not transferable. We studied 10 small forested research watersheds in the northeastern USA to determine if there were common factors related to soil ammonification and nitrification. Vegetation varied between mixed northern hardwoods and mixed conifers. Watershed surface soils (Oa or A horizons) were sampled at grid or transect points and analyzed for a suite of chemical characteristics. At each sampling point, vegetation and topographic metrics (field and GIS-based) were also obtained. Results were examined by watershed averages (n = 10), seasonal/watershed averages (n = 28), and individual sampling points (n = 608). Using both linear and tree regression techniques, the proportion of conifer species was the single best predictor of nitrification rates, with lower rates at higher conifer dominance. Similar to other studies, the soil C/N ratio was also a good predictor and was well correlated with conifer dominance. Unlike other studies, the presence of Acer saccharum was not by itself a strong predictor, but was when combined with the presence of Betula alleghaniensis. Topographic metrics (slope, aspect, relative elevation, and the topographic index) were not related to N transformation rates across the watersheds. Although found to be significant in other studies, neither soil pH, Ca nor Al was related to nitrification. Results showed a strong relationship between dominant vegetation, soil C, and soil C/N. ?? 2008 Springer Science+Business Media, LLC.

  13. INFLUENCE OF HEXAVALENT CHROMIUM INITIAL CONCENTRATION ON RETARDATION FACTOR AND CONTAMINANT VELOCITY IN A SOIL MEDIA

    Directory of Open Access Journals (Sweden)

    K. SHIVA PRASHANTH KUMAR

    2016-02-01

    Full Text Available Sources of soil and ground water contamination are many and include many folds of accidental spills and leaks of toxic and hazardous chemicals. Preparation of ground water contamination model needs good understanding of the behavior of contaminant transport through soil media for predicting the level of contamination of ground water in the near future at the intended site conditions. Sorption is a natural process; due to its presence, the contaminant can move slowly as compared to the ground water and hence the effects of sorption must be taken into consideration while predicting the travel time of the contaminant to reach the ground water sources. This paper discusses the results of column test studies carried out in the laboratory under controlled conditions about the spreading of contaminant (Hexavalent chromium, Cr (VI through the clay mixed red soil at two different initial concentrations (800 mg/L and 4200 mg/L. The variations of the contaminant flow velocity and retardation factor for two different initial concentrations of contaminant were brought out and discussed. The contaminant flow velocity drastically coming down for a relative concentration of 0 to 0.2 and beyond this range, the contaminant flow velocity value is decreasing in a slow rate for both the lower and higher initial contaminant concentrations tested. At the lower relative concentration, the higher retardation factor was observed and it may be due to slowly filling the available sorption sites in the soil column.

  14. Traffic-related trace elements in soils along six highway segments on the Tibetan Plateau: Influence factors and spatial variation.

    Science.gov (United States)

    Wang, Guanxing; Zeng, Chen; Zhang, Fan; Zhang, Yili; Scott, Christopher A; Yan, Xuedong

    2017-03-01

    The accumulation of traffic-related trace elements in soil as the result of anthropogenic activities raises serious concerns about environmental pollution and public health. Traffic is the main source of trace elements in roadside soil on the Tibetan Plateau, an area otherwise devoid of industrial emissions. Indeed, the rapid development of tourism and transportation in this region means it is becoming increasingly important to identify the accumulation levels, influence distance, spatial distribution, and other relevant factors influencing trace elements. In this study, 229 soil samples along six segments of the major transportation routes on the Tibetan Plateau (highways G214, S308, and G109), were collected for analysis of eight trace elements (Cr, Co, Ni, As, Cu, Zn, Cd, and Pb). The results of statistical analyses showed that of the eight trace elements in soils, Cu, Zn, Cd, and Pb were primarily derived from traffic. The relationship between the trace element accumulation levels and the distance from the roadside followed an exponential decline, with the exception of Segment 3, the only unpaved gravel road studied. In addition, the distance of influence from the roadside varied by trace element and segment, ranging from 16m to 144m. Background values for each segment were different because of soil heterogeneity, while a number of other potential influencing factors (including traffic volume, road surface material, roadside distance, land cover, terrain, and altitude) all had significant effects on trace-element concentrations. Overall, however, concentrations along most of the road segments investigated were at, or below, levels defined as low on the Nemero Synthesis index. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Evelise G.; Oliveira, Arno Heeren de, E-mail: evelise.lara@gmail.com, E-mail: heeren@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Rocha, Zildete; Rios, Francisco Javier, E-mail: rochaz@cdtn.br, E-mail: javier@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The {sup 226}Ra, {sup 232}Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The {sup 226}Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to {sup 232}Th and U content. The soil permeability is 5.0 x 10{sup -12}, which is considered average. The {sup 226}Ra (22.2 ± 0.3 Bq.m{sup -3}); U content (73.4 ± 3.6 Bq.kg{sup -1}) and {sup 232}Th content (55.3 ± 4.0 Bq.kg{sup -1}) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg{sup -1}) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m{sup -3}) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m{sup -3}). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  16. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    International Nuclear Information System (INIS)

    Lara, Evelise G.; Oliveira, Arno Heeren de

    2015-01-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The 226 Ra, 232 Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The 226 Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to 232 Th and U content. The soil permeability is 5.0 x 10 -12 , which is considered average. The 226 Ra (22.2 ± 0.3 Bq.m -3 ); U content (73.4 ± 3.6 Bq.kg -1 ) and 232 Th content (55.3 ± 4.0 Bq.kg -1 ) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg -1 ) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m -3 ) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m -3 ). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  17. Analysis of Factors Influencing Soil Salinity, Acidity, and Arsenic Concentration in a Polder in Southwest Bangladesh

    Science.gov (United States)

    Ayers, J. C.; Patton, B.; Fry, D. C.; Goodbred, S. L., Jr.

    2017-12-01

    Soil samples were collected on Polder 32 in the coastal zone of SW Bangladesh in wet (October) and dry (May) seasons from 2013-2017 and analyzed to characterize the problems of soil salinization and arsenic contamination and identify their causes. Soils are entisols formed from recently deposited, predominantly silt-sized sediments with low carbon concentrations typical of the local mangrove forests. Soluble (DI extract) arsenic concentrations were below the Government of Bangladesh limit of 50 ppb for drinking water. Soil acidity and extract arsenic concentrations exhibit spatial variation but no consistent trends. In October soil extract As is higher and S and pH are lower than in May. These observations suggest that wet season rainwater oxidizes pyrite, reducing soil S and releasing H+, causing pH to decrease. Released iron is oxidized to form Hydrous Ferric Oxyhydroxides (HFOs), which sorb As and increase extractable As in wet season soils. Changes in pH are small due to pH buffering by soil carbonates. Soil and rice paddy water salinities are consistently higher in May than October, reaching levels in May that reduce rice yields. Rice grown in paddies should be unaffected by salt concentrations in the wet season, while arsenic concentrations in soil may be high enough to cause unsafe As levels in produced rice.

  18. Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2014-01-01

    Full Text Available The integration of bioventing (BV and soil vapor extraction (SVE appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5% of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

  19. Toluene removal from sandy soils via in situ technologies with an emphasis on factors influencing soil vapor extraction.

    Science.gov (United States)

    Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Momenbeik, Fariborz; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

    2014-01-01

    The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

  20. Experimental study on the solidification and influence factors of MSW stabilized soil

    Directory of Open Access Journals (Sweden)

    Wang Zhiping

    2015-01-01

    Full Text Available The effect of kinds and dosage of curing agent on the curing effect and strength characteristics of municipal solid waste (MSW stabilized soil is very obvious. In order to reveal these effects, this paper uses cement, fly ash, lime and gypsum as main curing agent and additives to make MSW stabilized soil samples of different components and contents and its strength is obtained using unconfined compressive strength test. The results showed that the curing age, dosage of cement, fly ash, lime and gypsum have effect on the strengths of stabilized MSW soil. The bigger the content of cement and fly ash, the higher the strength of stabilized soil. But the amount of lime and gypsum has a critical value. Within the critical value, the strength of the stabilized soil increases with the increasing of the content of the additives, and decreases with the increase of the additives content if the content of the additives exceeds the critical value. The curing age has much effect on the strength of the stabilized soil. The strength of the samples for 7 days is far less than that for 28 days. This can be explained that: when the curing agent is added into the stabilized soil, the connection among the particles of the MSW soil is changed from weak connection to bond connection, and therefore the strength of the curing MSW soil is improved.

  1. Factors influencing soil aggregation and particulate organic matter responses to bioenergy crops across a topographic gradient

    Science.gov (United States)

    Todd A. Ontl; Cynthia A. Cambardella; Lisa A. Schulte; Randall K. Kolka

    2015-01-01

    Bioenergy crops have the potential to enhance soil carbon (C) pools from increased aggregation and the physical protection of organic matter; however, our understanding of the variation in these processes over heterogeneous landscapes is limited. In particular, little is known about the relative importance of soil properties and root characteristics for the physical...

  2. Lead (Pb) and other metals in New York City community garden soils: factors influencing contaminant distributions.

    Science.gov (United States)

    Mitchell, Rebecca G; Spliethoff, Henry M; Ribaudo, Lisa N; Lopp, Donna M; Shayler, Hannah A; Marquez-Bravo, Lydia G; Lambert, Veronique T; Ferenz, Gretchen S; Russell-Anelli, Jonathan M; Stone, Edie B; McBride, Murray B

    2014-04-01

    Urban gardens provide affordable fresh produce to communities with limited access to healthy food but may also increase exposure to lead (Pb) and other soil contaminants. Metals analysis of 564 soil samples from 54 New York City (NYC) community gardens found at least one sample exceeding health-based guidance values in 70% of gardens. However, most samples (78%) did not exceed guidance values, and medians were generally below those reported in NYC soil and other urban gardening studies. Barium (Ba) and Pb most frequently exceeded guidance values and along with cadmium (Cd) were strongly correlated with zinc (Zn), a commonly measured nutrient. Principal component analysis suggested that contaminants varied independently from organic matter and geogenic metals. Contaminants were associated with visible debris and a lack of raised beds; management practices (e.g., importing uncontaminated soil) have likely reduced metals concentrations. Continued exposure reduction efforts would benefit communities already burdened by environmental exposures. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Lead (Pb) and other metals in New York City community garden soils: factors influencing contaminant distributions

    Science.gov (United States)

    Mitchell, Rebecca G.; Spliethoff, Henry M.; Ribaudo, Lisa N.; Lopp, Donna M.; Shayler, Hannah A.; Marquez-Bravo, Lydia G.; Lambert, Veronique T.; Ferenz, Gretchen S.; Russell-Anelli, Jonathan M.; Stone, Edie B.; McBride, Murray B.

    2014-01-01

    Urban gardens provide affordable fresh produce to communities with limited access to healthy food but may also increase exposure to lead (Pb) and other soil contaminants. Metals analysis of 564 soil samples from 54 New York City (NYC) community gardens found at least one sample exceeding health-based guidance values in 70% of gardens. However, most samples (78%) did not exceed guidance values, and medians were generally below those reported in NYC soil and other urban gardening studies. Barium (Ba) and Pb most frequently exceeded guidance values and along with cadmium (Cd) were strongly correlated with zinc (Zn), a commonly measured nutrient. Principal component analysis suggested that contaminants varied independently from organic matter and geogenic metals. Contaminants were associated with visible debris and a lack of raised beds; management practices (e.g., importing uncontaminated soil) have likely reduced metals concentrations. Continued exposure reduction efforts would benefit communities already burdened by environmental exposures. PMID:24502997

  4. Lead (Pb) and other metals in New York City community garden soils: Factors influencing contaminant distributions

    International Nuclear Information System (INIS)

    Mitchell, Rebecca G.; Spliethoff, Henry M.; Ribaudo, Lisa N.; Lopp, Donna M.; Shayler, Hannah A.; Marquez-Bravo, Lydia G.; Lambert, Veronique T.; Ferenz, Gretchen S.; Russell-Anelli, Jonathan M.; Stone, Edie B.; McBride, Murray B.

    2014-01-01

    Urban gardens provide affordable fresh produce to communities with limited access to healthy food but may also increase exposure to lead (Pb) and other soil contaminants. Metals analysis of 564 soil samples from 54 New York City (NYC) community gardens found at least one sample exceeding health-based guidance values in 70% of gardens. However, most samples (78%) did not exceed guidance values, and medians were generally below those reported in NYC soil and other urban gardening studies. Barium (Ba) and Pb most frequently exceeded guidance values and along with cadmium (Cd) were strongly correlated with zinc (Zn), a commonly measured nutrient. Principal component analysis suggested that contaminants varied independently from organic matter and geogenic metals. Contaminants were associated with visible debris and a lack of raised beds; management practices (e.g., importing uncontaminated soil) have likely reduced metals concentrations. Continued exposure reduction efforts would benefit communities already burdened by environmental exposures. - Highlights: • We measured metals concentrations in soil from 54 New York City community gardens. • Pb and Ba exceeded health-based guidance values in 9%–12% of garden beds. • Pb concentrations were similar to those in other studies of urban garden soils. • Pb and Ba were associated with Zn, with visible debris, and with non-raised beds. • Observable details can help gardeners focus testing and exposure reduction efforts. - Pb and Ba, which exceeded health-based guidance values in 10–14% of NYC community garden soil samples, are associated with non-raised beds, visible debris, higher pH and Zn

  5. [Influence on AM fungi infection rate and medicine quality of Pinellia ternata in condition of three soil impact factors].

    Science.gov (United States)

    Shen, Xue-Lian; Liu, Zuo-Yi; Guo, Qiao-Sheng; Zhu, Guo-Sheng; Cheng, Li-Tao

    2013-04-01

    To explore the influence on AM fungi infection rate and medicine quality of Pinellia ternate in the condition of three soil impact factors. Set the orthogonal test of three factors and levels. Determinate the AM fungi infection rate in early stage of mature & stage of mature of P. ternata, and the water content, water soluble extract, butanedioic acid content and alkaloid content of P. ternata tuber that be harvested also had be determinated. With the P levels to 30 mg x kg(-1) and 90 mg x kg(-1), AM fungi infection was the best when mixed inoculated of EM. Microbial agent inoculated played a decisive role in P. ternata growth and physiological activity, secondary influenced factor was P concentration, and the water stress was the minimal impact. Mixed inoculated of AM fungi and EM treatment with the low P levels (30, 90 mg x kg(-1)) proved better effect on enhancing the water extract content, anedioic acid and alkaloid content, while decreasing the water contents of P. ternata tuber.

  6. Quantitative Analysis of the Factors Influencing Soil Heavy Metal Lateral Migration in Rainfalls Based on Geographical Detector Software: A Case Study in Huanjiang County, China

    Directory of Open Access Journals (Sweden)

    Pengwei Qiao

    2017-07-01

    Full Text Available Quantitative analysis of the factors influencing heavy metal migration could be useful for controlling heavy metal migration. In this paper, a geographical detector was used to calculate the contributions of and interactions among factors in Huanjiang County, South China, covering an area of 273 km2. In this paper, nine factors were analyzed. The results showed that, among these factors, soil type was the main factor influencing the migration of As, Pb and Cd; the other eight factors did not have big differences and were lower than soil type. In addition, there were obvious synergistic effects between the soil type and concentration of water-soluble heavy metals (CWS and the concentration of water-insoluble heavy metals (CWI and NDVI. Therefore, these factors of the study area were especially focused on. Furthermore, the results of the key factor identification and the high-risk region identification in the nine factors were reliable, based on the geographical detector software. Therefore, the geographical detector software could be used as an effective tool to quantitatively analyze the contribution of the factors, and identify the high-risk regions for the factors influencing soil heavy metal lateral migration in rainfalls.

  7. [Analysis of soil respiration and influence factors in wheat farmland under conservation tillage in southwest hilly region].

    Science.gov (United States)

    Zhang, Sai; Zhang, Xiao-Yu; Wang, Long-Chang; Luo, Hai-Xiu; Zhou, Hang-Fei; Ma, Zhong-Lian; Zhang, Cui-Wei

    2013-07-01

    In order to investigate the effect of conservation tillage on soil respiration in dry cropping farmland in southwest purple hilly region, the LI6400-09 respiratory chamber was adopted in the experiment conducted in the experimental field in Southwest University in Beibei, Chongqing. The respiration and the hydrothermal and biotic factors of soil were measured and analyzed during the growth period of wheat in the triple intercropping system of wheat/maize/soybean. There were four treatments including T (traditional tillage), R (ridge tillage), TS (traditional tillage + straw mulching) and RS (ridge tillage + straw mulching), which were all in triplicates. The results indicated that the soil respiration rate changed in the range of 1.100-2.508 micromol x (m2 x s)(-1) during the reproductive growth stage of wheat. There were significant differences in soil respiration rate among different treatments, which could be ranked as RS > R > TS > T. The soil temperature in the 10cm layer was ranked as T > R > TS > RS. The relationship between soil respiration and soil temperature fitted well with an exponential function, in which the Q10 values were 1.25, 1.20, 1.31 and 1.26, respectively. The soil moisture in the 5cm layer was ranked as TS > RS > T > R. The best fitting model between soil moisture and soil respiration was a parabolic curve, indicating the presence of soil moisture with the strongest soil respiration. The response threshold of wheat to soil moisture was 14.80%-17.47% during the reproductive stage. The dominant groups of soil animals were Collembola and Acarina, which were correlated with soil respiration to some extent. The correlation was high in the treatments T and R, ranged from 0.669-0.921, whereas there was no remarkable correlation in the other treatments.

  8. Factors influencing As(V) stabilization in the mine soils amended with iron-rich materials.

    Science.gov (United States)

    Kim, Mijin; Kim, Juhee; Kim, Minhee; Kim, Yong-Seong; Nam, Seung Mo; Moon, Deok Hyun; Hyun, Seunghun

    2017-09-04

    Chemical stability of As(V) in amended mine-impacted soils was assessed according to functions of incubation period (0, 1, 2, 4, and 6 months), amendment dose (2.5 and 5%), and application timing (0 and 3rd month). Six soils contaminated with 26-209 mg kg -1 of As(V) were collected from two abandoned mine sites and were treated with two alkaline iron-rich materials (mine discharge sludge (MS) and steel-making slag (SS)). Seventeen to 23% of As(V) in soils was labile. After each designated time, As(V) stability was assessed by the labile fractions determined with sequential extraction procedures (F1-F5). Over 6 months, a reduction (26.9-70.4%) of the two labile fractions (F1 and F2) and a quantitative increase (7.4-29.9%) of As(V) in F3 were observed (r 2  = 0.956). Two recalcitrant fractions (F4 and F5) remained unchanged. Temporal change of As(V) stability in a sample was well described by the two-domain model (k fast , k slow , and F fast ). The stabilization (%) correlated well with the fast-stabilizing domain (F fast ), clay content (%), and Fe oxide content (mg kg -1 ), but correlated poorly with kinetic rate constants (k fast and k slow ). Until the 3rd month, the 2.5%-MS amended sample resulted in lower As(V) stabilization (25-40%) compared to the 5% sample (50-60%). However, the second 2.5% MS addition on the 2.5% sample upon the lapse of the 3rd month led to a substantial reduction (up to 38%) of labile As(V) fraction in the following 4th and 6th months. As a result, an additional 15-25% of As(V) stability was obtained when splitting the amendment dose into 3-month intervals. In conclusion, the As(V) stabilization by Fe-rich amendment is time-dependent and its efficacy can be improved by optimizing the amendment dose and its timing.

  9. Factors influencing U(VI adsorption onto soil from a candidate very low level radioactive waste disposal site in China

    Directory of Open Access Journals (Sweden)

    Zuo Rui

    2016-01-01

    Full Text Available The properties of soil at disposal sites are very important for geological disposal of very low level radioactive waste in terms of U(VI. In this study, soil from a candidate very low level radioactive waste disposal site in China was evaluated for its capacity on uranium sorption. Specifically, the equilibrium time, initial concentration, soil particle, pH, temperature, and carbonate were evaluated. The results indicated that after 15-20 days of sorption, the Kd value fluctuated and stabilized at 355-360 mL/g. The adsorptive capacity of uranium was increased as the initial uranium concentration increased, while it decreased as the soil particle size increased. The pH value played an important role in the U(VI sorption onto soil, especially under alkaline conditions, and had a great effect on the sorption capacity of soil for uranium. Moreover, the presence of carbonate decreased the sorption of U(VI onto soil because of the role of the strong complexation of carbonate with U(VI in the groundwater. Overall, this study assessed the behavior of U(VI sorption onto natural soil, which would be an important factor in the geological barrier of the repository, has contribution on mastering the characteristic of the adsorption of uranium in the particular soil media for the process of very low level radioactive waste disposal.

  10. The role of soil biogeochemistry in wine taste: Soil factors influencing grape elemental composition, photosynthetic biomarkers and Cu/Zn isotopic signature of Vitis vinifera

    Science.gov (United States)

    Blotevogel, Simon; Oliva, Priscia; Darrozes, José; Viers, Jérôme; Audry, Stéphane; Courjault-Radé, Pierre; Orgogozo, Laurent; Le Guedard, Marina; Schreck, Eva

    2015-04-01

    Understanding the influence of soil composition in wine taste is of great economic and environmental interest in France and around the world. Nevertheless the impact of soil composition on wine taste is still controversially discussed. Since inorganic soil components do not have a proper taste and do not enter the plant anyway, their influence needs to be induced by nutrient absorption and its impact on plant functioning and grape composition. Indeed recent development of geological tracers of origin proof the existence of soil chemical and isotopic signatures in wine. However, type and scale of the impact of soil composition on wine taste are not well understood yet, and little experimental evidence exists due to the complexity of mechanisms involved. Thus, to provide evidence for the impact of soil composition on grape composition and potentially wine taste, we studied soil and plant material from two relevant vineyards (Soave, Italia). On those two directly adjacent vineyards, two different wines are produced with the same plant material and cultivation techniques. The vineyards only differ by their underlying bedrock - limestone versus basaltic rock - and thus present suitable conditions for investigating the impact of soil composition on grapes and wine. Pedological and mineralogical parameters were analyzed for the two vineyards whereas chemical extractions (citrate, CaCl2) were performed to determine nutrient bioavailability in both soils. Elemental compositions were determined by ICP-MS analyses in different compartments (soils, vine leaves and grapes). Isotopic fractionation of Cu and Zn was investigated in various samples as source tracers and in order to better understand fractionation mechanisms involved. Finally, plant health was studied using the Omega-3 biomarker which determines the fatty acid composition in vine leaves, directly involved in photosynthetic processes. Results show that the vineyards are characterized by two different soil types due

  11. Prediction of soil urea conversion and quantification of the importance degrees of influencing factors through a new combinatorial model based on cluster method and artificial neural network.

    Science.gov (United States)

    Lei, Tao; Guo, Xianghong; Sun, Xihuan; Ma, Juanjuan; Zhang, Shaowen; Zhang, Yong

    2018-05-01

    Quantitative prediction of soil urea conversion is crucial in determining the mechanism of nitrogen transformation and understanding the dynamics of soil nutrients. This study aimed to establish a combinatorial prediction model (MCA-F-ANN) for soil urea conversion and quantify the relative importance degrees (RIDs) of influencing factors with the MCA-F-ANN method. Data samples were obtained from laboratory culture experiments, and soil nitrogen content and physicochemical properties were measured every other day. Results showed that when MCA-F-ANN was used, the mean-absolute-percent error values of NH 4 + -N, NO 3 - -N, and NH 3 contents were 3.180%, 2.756%, and 3.656%, respectively. MCA-F-ANN predicted urea transformation under multi-factor coupling conditions more accurately than traditional models did. The RIDs of reaction time (RT), electrical conductivity (EC), temperature (T), pH, nitrogen application rate (F), and moisture content (W) were 32.2%-36.5%, 24.0%-28.9%, 12.8%-15.2%, 9.8%-12.5%, 7.8%-11.0%, and 3.5%-6.0%, respectively. The RIDs of the influencing factors in a descending order showed the pattern RT > EC > T > pH > F > W. RT and EC were the key factors in the urea conversion process. The prediction accuracy of urea transformation process was improved, and the RIDs of the influencing factors were quantified. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Remediation of polybrominated diphenyl ethers in soil using Ni/Fe bimetallic nanoparticles: Influencing factors, kinetics and mechanism

    International Nuclear Information System (INIS)

    Xie, Yingying; Fang, Zhanqiang; Cheng, Wen; Tsang, Pokeung Eric; Zhao, Dongye

    2014-01-01

    Polybrominated diphenyl ethers (PBDEs) are commonly used as additive flame retardants in all kinds of electronic products. PBDEs are now ubiquitous in the environment, with soil as a major sink, especially in e-waste recycling sites. This study investigated the degradation of decabromodiphenyl ether (BDE209) in a spiked soil using Ni/Fe bimetallic nanoparticles. The results indicated that Ni/Fe bimetallic nanoparticles are able to degrade BDE209 in soil at ambient temperature and the removal efficiency can reach 72% when an initial pH of 5.6 and at a Ni/Fe dosage of 0.03 g/g. A declining trend in degradation was noticed with decreasing Ni loading and increasing of initial BDE209 concentration. The degradation products of BDE209 were analyzed by GC-MS, which showed that the degradation of BDE209 was a process of stepwise debromination from nBr to (n − 1)Br. And a possible debromination pathway was proposed. At last, the degradation process was analyzed as two-step mechanism, mass transfer and reaction. This current study shows the potential ability of Ni/Fe nanoparticles to be used for removal of PBDEs in contaminated soil. - Highlights: • Ni/Fe bimetallic nanoparticles could effectively degradate BDE209 in soil. • The effects of various factors on remediation of BDE209 in soil using Ni/Fe were considered. • The degradation of BDE209 was a process of stepwise debromination from nBr to (n − 1)Br. • A possible debromination pathway and mechanism about removal of BDE209 in soil were proposed

  13. The Influence of Edaphic and Orographic Factors on Algal Diversity in Biological Soil Crusts on Bare Spots in the Polar and Subpolar Urals

    Science.gov (United States)

    Patova, E. N.; Novakovskaya, I. V.; Deneva, S. V.

    2018-03-01

    The influence of edaphic and orographic factors on the formation of algal diversity in biological soil crusts was studied in mountain tundras of the Polar and Subpolar Urals. Bare spots developed in the soils on different parent materials and overgrown to different extents were investigated. Overall, 221 algal species from six divisions were identified. Among them, eighty-eight taxa were new for the region studied. The Stigonema minutum, S. ocellatum, Nostoc commune, Gloeocapsopsis magma, Scytonema hofmannii, Leptolyngbya foveolarum, Pseudococcomyxa simplex, Sporotetras polydermatica species and species of the Cylindrocystis, Elliptochloris, Fischerella, Leptosira, Leptolyngbya, Myrmecia, Mesotaenium, Phormidium, Schizothrix genera were permanent components of biological soil crusts. The basis of the algal cenoses in soil crusts was composed of cosmopolitan cyanoprokaryotes, multicellular green algae with thickened covers and abundant mucus. The share of nitrogen fixers was high. The physicochemical properties of primary soils forming under the crusts of spots are described. The more important factors affecting the species composition of algae in the crusts are the elevation gradient, temperature, soil moisture, and the contents of Ca, Mg, mobile phosphorus, and total nitrogen.

  14. Influence of land use and meteorological factors on the spatial distribution of Toxocara canis and Toxocara cati eggs in soil in urban areas.

    Science.gov (United States)

    Gao, Xiang; Wang, Hongbin; Li, Jianxin; Qin, Hongyu; Xiao, Jianhua

    2017-01-15

    Soil which has been contaminated by Toxocara spp. eggs is considered as one of the main infection sources of Toxocariasis in animals and humans. The present study conducted a detailed investigation into the spatial patterns of Toxocara canis (T. canis) and Toxocara cati (T. cati) eggs in soil in urban area of northeastern Mainland China, and assessed the inter-relationships between meteorological factors, land use and the distribution of the Toxocara spp. eggs. Polymerase chain reaction (PCR) was used for the determination of T. canis and T. cati eggs contamination in soil samples. Between April 2014 and May 2015, 9420 soil samples were subjected to PCR examination and 7027 sheep (74.6%) were determined to be positive for T. canis and T. cati eggs. Subsequently, we evaluated the effect of land use, and meteorological factors on the spatial distribution of T. canis and T. cati eggs based on a maximum entropy model. Jackknife analysis revealed that the area of residential land, wood and grass land and precipitation may influence the occurrence of T. canis and T. cati eggs in soil. Our findings indicate that land use and meteorological factors may be important variables affecting transmission of Toxocariasis and should be taken into account in the development of future surveillance programmes for Toxocariasis. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Relative influence of soil chemistry and topography on soil available micronutrients by structural equation modeling

    OpenAIRE

    Zhu, Hongfen; Zhao, Ying; Nan, Feng; Duan, Yonghong; Bi, Rutian

    2016-01-01

    Soil chemical and topographic properties are two important factors influencing available micronutrient distribution of soil in the horizontal dimension. The objective of this study was to explore the relative influence of soil chemistry (including soil pH, soil organic matter, total nitrogen, available phosphorus, and available potassium) and topography (including elevation, slope, aspect, and wetness index) on the availability of micronutrients (Fe, Mn, Cu, Zn, and B) using structural equati...

  16. Influence of soil moisture content on surface albedo and soil thermal ...

    Indian Academy of Sciences (India)

    Half hourly data of soil moisture content, soil temperature, solar irradiance, and reflectance are measured ... and the influence of solar elevation angle and cloud cover are also investigated. .... ters are important factors in climate modelling and.

  17. Influence of Height Waterlogging on Soil Physical Properties of Potential and Actual Acid Sulphate Soils

    Directory of Open Access Journals (Sweden)

    Arifin Fahmi

    2014-06-01

    Full Text Available Water management is main factor that determines the successful of rice cultivation in acid sulphate soil. Soil waterlogging determines the direction and rate of chemical, geochemical and biological reaction in the soil, indirectly these reactions may influence to the changes of soil psycal properties during soil waterlogging process. The experiment was aimed to study the changes of two type of acid sulphate soils physical properties during rice straw decomposition processes. The research was conducted in the greenhouse consisting of the three treatment factors using the completely randomized design with three replications. The first factor was soil type: potential acid sulphate soil (PASS and actual acid sulphate soil (AASS. The second factor was height of water waterlogging: 0.5-1.0 cm (muddy water–level condition and 4.0 cm from above the soil surface (waterlogged. The third factor was organic matter type: rice straw (RS, purun tikus (Eleocharis dulcis (PT and mixed of RS and PT (MX. Soil physical properties such as aggregate stability, total soil porosity, soil permeability, soil particle density and bulk density were observed at the end of experiment (vegetative maximum stage. The results showed that acid sulphate soil type had large effect on soil physicl properties, soil waterlogging decreased aggregate stability, soil particle density and bulk density both of soil type.

  18. A Meta-analysis of Interannual Changes and the Influencing Factors of Soil Water and Organic Carbon in Apple Orchard of Southern Loess Plateau

    Science.gov (United States)

    Wang, Y.; Liu, W.; LI, G.

    2017-12-01

    The Loess Plateau is located in the upper and middle reaches of the Yellow River basin, its southern part is a world famous production area for high quality apple. In recent years, as an agricultural mainstay industry, the region apple planting area and total output reach 1.3 million ha and 15 million tons respectively, which account for about 60% and 55% of the country. In the 1980s, an apple producing base on the Shannxi Weibei Plateau was established, and its planting area accounted for more than50% of arable land in recent years. Due to lack of irrigation conditions in the region, the apple cultivation depends mainly on rain water resources. In the backdrop of a large scale project of grain to green and with constantly expanding of farmland into orchard in the region, soil water balance and soil environments have changed considerably under the new agro-fruit production system. This paper presents an integrative analysis of the related researches regarding the variation characteristics of soil water, organic carbon and their influencing factors of apple orchard. Results on soil hydrology are summarized as: (i) for young orchards, depth of soil moisture depleted by root system extended downward with orchard age increasing; (ii) because the water consumption of fruit trees exceeded the recharged water from precipitation in a year, soil moisture of orchard decreased continuously and reached the minimum in the full fruit period, followed by a certain degree of recovery; (iii) depth distribution of dry soil layer (DSL)showed a trend of increasing year by year, which existed in 3.5-10 m in the full fruit period. The presence of DSL blocks the recharging of groundwater by rainwater infiltration. Results on soil organic carbon (SOC) show that: the SOC content increased gradually with time when orchard was under 15 years old, reached to the maximum SOC content, 6.66g/kg of 0-100cm for the 15 year old orchard, and then slightly decreased. The SOC content in 0-20cm soil

  19. Occurrence and air-soil exchange of organochlorine pesticides and polychlorinated biphenyls at a CAWNET background site in central China: Implications for influencing factors and fate.

    Science.gov (United States)

    Zhan, Lingxi; Lin, Tian; Wang, Zuwu; Cheng, Zhineng; Zhang, Gan; Lyu, Xiaopu; Cheng, Hairong

    2017-11-01

    Ambient air and soil samples were collected between March 2012 and March 2013 at Jinsha, a regional background site in central China, to measure the concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The average concentrations of total OCPs and total PCBs were 191 ± 107 and 39.4 ± 27.1 pg/m 3 in air (gaseous and particulate phase) and 0.585 ± 0.437 and 0.083 ± 0.039 ng/g in soil, respectively. The higher concentrations of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and p,p'-DDT/p,p'-DDE ratios in the soil indicated recent p,p'-DDT input to the soil. A strong positive temperature dependence and average fugacity fraction value > 0.5 were observed for p,p'-DDT, suggesting that volatilization of residual DDT in the soil was the main influencing factor on atmospheric p,p'-DDT. Highly average fugacity fractions (>0.7) of trans-chlordane (TC) and cis-chlordane (CC) and high TC/CC ratios both in the soil and atmosphere suggested fresh inputs. Higher gaseous concentrations of hexachlorobenzene (HCB) were observed in winter and negative temperature dependence was directly attributed to the surrounding ongoing source (e.g. fuel consuming activities), especially in winter. Overall, most targeted OCPs and PCBs were influenced by long-range transport, and fugacity fraction values indicated highly volatile compounds (e.g. α-hexachlorocyclohexane (α-HCH) and lower chlorinated PCBs) were volatilized and low volatility compounds (e.g. p,p'-DDE and higher chlorinated PCBs) were deposited at the air-soil interface. Knowing the source and sink of OCPs and PCBs can help to control their pollution in this area and provide a reference for other studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Geochemical and biotic factors influencing the diversity and distribution of soil microfauna across ice-free coastal habitats in Victoria Land, Antarctica

    Czech Academy of Sciences Publication Activity Database

    Smykla, J.; Porazinska, D. L.; Iakovenko, Nataliia; Devetter, Miloslav; Drewnik, M.; Siang Hii, Y.; Emslie, S.D.

    2018-01-01

    Roč. 116, č. 1 (2018), s. 265-276 ISSN 0038-0717 Institutional support: RVO:67985904 ; RVO:60077344 Keywords : habitat suitability * soil biodiversity * Nematodes Subject RIV: DF - Soil Science OBOR OECD: Soil science Impact factor: 4.857, year: 2016

  1. Vertebrate herbivores influence soil nematodes by modifying plant communities

    NARCIS (Netherlands)

    Veen, G. F. (Ciska); Olff, Han; Duyts, Henk; van der Putten, Wim H.

    Abiotic soil properties, plant community composition, and herbivory all have been reported as important factors influencing the composition of soil communities. However, most studies thus far have considered these factors in isolation, whereas they strongly interact in the field. Here, we study how

  2. [Natural factors influencing sleep].

    Science.gov (United States)

    Jurkowski, Marek K; Bobek-Billewicz, Barbara

    2007-01-01

    Sleep is a universal phenomenon of human and animal lives, although the importance of sleep for homeo-stasis is still unknown. Sleep disturbances influence many behavioral and physiologic processes, leading to health complications including death. On the other hand, sleep improvement can beneficially influence the course of healing of many disorders and can be a prognostic of health recovery. The factors influencing sleep have different biological and chemical origins. They are classical hormones, hypothalamic releasing and inhibitory hormones, neuropeptides, peptides and others as cytokines, prostaglandins, oleamid, adenosine, nitric oxide. These factors regulate most physiologic processes and are likely elements integrating sleep with physiology and physiology with sleep in health and disorders.

  3. Soil pH, total phosphorus, climate and distance are the major factors influencing microbial activity at a regional spatial scale

    DEFF Research Database (Denmark)

    Cao, Haichuan; Chen, Ruirui; Wang, Libing

    2016-01-01

    Considering the extensive functional redundancy in microbial communities and great difficulty in elucidating it based on taxonomic structure, studies on the biogeography of soil microbial activity at large spatial scale are as important as microbial community structure. Eighty-four soil samples...... scaling clearly revealed that soil microbial activities showed distinct differentiation at different sites over a regional spatial scale, which were strongly affected by soil pH, total P, rainfall, temperature, soil type and location. In addition, microbial community structure was greatly influenced...... scales. There are common (distance, climate, pH and soil type) but differentiated aspects (TP, SOC and N) in the biogeography of soil microbial community structure and activity....

  4. Analyses of the influencing factors of soil microbial functional gene diversity in tropical rainforest based on GeoChip 5.0.

    Science.gov (United States)

    Cong, Jing; Liu, Xueduan; Lu, Hui; Xu, Han; Li, Yide; Deng, Ye; Li, Diqiang; Zhang, Yuguang

    2015-09-01

    To examine soil microbial functional gene diversity and causative factors in tropical rainforests, we used a microarray-based metagenomic tool named GeoChip 5.0 to profile it. We found that high microbial functional gene diversity and different soil microbial metabolic potential for biogeochemical processes were considered to exist in tropical rainforest. Soil available nitrogen was the most associated with soil microbial functional gene structure. Here, we mainly describe the experiment design, the data processing, and soil biogeochemical analyses attached to the study in details, which could be published on BMC microbiology Journal in 2015, whose raw data have been deposited in NCBI's Gene Expression Omnibus (accession number GSE69171).

  5. Soil - plant experimental radionuclide transfer factors

    International Nuclear Information System (INIS)

    Dobrin, R.I.; Dulama, C.N.; Toma, Al.

    2006-01-01

    Some experimental research was performed in our institute to assess site specific soil-plant transfer factors. A full characterization of an experimental site was done both from pedo-chemical and radiological point of view. Afterwards, a certain number of culture plants were grown on this site and the evolution of their radionuclide burden was then recorded. Using some soil amendments one performed a parallel experiment and the radionuclide root uptake was evaluated and recorded. Hence, transfer parameters were calculated and some conclusions were drawn concerning the influence of site specific conditions on the root uptake of radionuclides. (authors)

  6. [Soil organic carbon sequestration rate and its influencing factors in farmland of Guanzhong Plain: a case study in Wugong County, Shannxi Province].

    Science.gov (United States)

    Zhang, Xiao-Wei; Xu, Ming-Xiang

    2013-07-01

    Take Wugong County as an example, soil carbon storage and soil carbon sequestration rate were calculated, the change law of farmland soil organic carbon was explored, and the relationship of farmland soil organic carbon and natural factors, human factors was further revealed. The results of the study showed that: (1) The soil organic carbon contents in 80% of the sampling sites were in the range of 8.0-12.0 g x kg(-1), and the organic carbon contents in 0-20 cm soils showed a normal distribution. (2) In 2011, the organic carbon density of the 0-20 cm farmland soil was 26.3 t x hm(-2), below the national average soil organic carbon density (33.45 t x hm(-2)) of the arable layer. In the last 30 years, the soil carbon sequestration rate in the 0-20 cm layer was 71.3 kg x (hm2 x a)(-1), and in the past five years, the carbon sequestration rate was 480 kg x (hm x a)(-1). The recent carbon sequestration rate was higher than the national average soil carbon sequestration rate of the arable layer [380.78 kg x (hm2 x a)(-1)]. (3) In the semi-humid plain region, soil organic carbon was mainly affected by soil types, landform types, organic fertilizer. Soil types accounted for 30.2% of the organic carbon variability; the landform types and the organic fertilizer could explain 37.7% and 32.1%, respectively. The results of the comprehensive analysis showed that the farmland soil organic carbon density of Wugong County in the past 30 years is increasing, and this probably relies on the utilization of chemical fertilizer and the returning straw. Further study should be conducted on the impact of the chemical fertilizer and returning straw.

  7. Analyses of the influencing factors of soil microbial functional gene diversity in tropical rainforest based on GeoChip 5.0

    Directory of Open Access Journals (Sweden)

    Jing Cong

    2015-09-01

    Full Text Available To examine soil microbial functional gene diversity and causative factors in tropical rainforests, we used a microarray-based metagenomic tool named GeoChip 5.0 to profile it. We found that high microbial functional gene diversity and different soil microbial metabolic potential for biogeochemical processes were considered to exist in tropical rainforest. Soil available nitrogen was the most associated with soil microbial functional gene structure. Here, we mainly describe the experiment design, the data processing, and soil biogeochemical analyses attached to the study in details, which could be published on BMC microbiology Journal in 2015, whose raw data have been deposited in NCBI's Gene Expression Omnibus (accession number GSE69171.

  8. Soil-transmitted helminthiasis: a critical but neglected factor influencing school participation of Aboriginal children in rural Malaysia.

    Science.gov (United States)

    Ahmed, Abdulhamid; Al-Mekhlafi, Hesham M; Azam, Mohammad Nurul; Ithoi, Init; Al-Adhroey, Abdulelah H; Abdulsalam, Awatif M; Surin, Johari

    2012-05-01

    Soil-transmitted helminthiasis (STH), among the most common neglected tropical diseases, is a major public health problem in Malaysia with a possible impact on the nutritional status and school participation of rural children. This study was carried out among Aboriginal schoolchildren, living in an endemic area for STH in Malaysia, to determine the possible relationship between intestinal helminthiasis and school absenteeism. We also evaluated whether successful treatment of the infection will affect school attendance among the subjects. Stool analysis revealed that more than 90% of the subjects were infected with at least 1 helminth species, with Ascaris lumbricoides and Trichuris trichiura infections being most prevalent. Infection of moderate-to-heavy worm burdens, low level of fathers' education and anaemia were identified as the significant predictors of high absenteeism among the subjects (P<0·05). Following treatment of the infected children, it was found that school absenteeism was reduced significantly (P<0·01). In conclusion, STH continues to have significant impacts on public health, particularly in rural communities with a negatively significant effect on the school participation of Aboriginal children. A school-based de-worming programme should be introduced and incorporated in the current educational assistance targeted towards the Aboriginal communities, under the auspices of the government.

  9. Why is the influence of soil macrofauna on soil structure only considered by soil ecologists ?

    OpenAIRE

    Bottinelli, N.; Jouquet, Pascal; Capowiez, Y.; Podwojewski, Pascal; Grimaldi, Michel; Peng, X.

    2015-01-01

    These last twenty years have seen the development of an abundant literature on the influence of soil macrofauna on soil structure. Amongst these organisms, earthworms, termites and ants are considered to play a key role in regulating the physical, chemical and microbiological properties of soils. Due to these influential impacts, soil ecologists consider these soil macro-invertebrates as ‘soil engineers’ and their diversity and abundance are nowadays considered as relevant bioindi...

  10. Using 137 Cs measurements to investigate the influence of erosion and soil redistribution on soil properties.

    Science.gov (United States)

    Du, P; Walling, D E

    2011-05-01

    Information on the interaction between soil erosion and soil properties is an important requirement for sustainable management of the soil resource. The relationship between soil properties and the soil redistribution rate, reflecting both erosion and deposition, is an important indicator of this interaction. This relationship is difficult to investigate using traditional approaches to documenting soil redistribution rates involving erosion plots and predictive models. However, the use of the fallout radionuclide (137)Cs to document medium-term soil redistribution rates offers a means of overcoming many of the limitations associated with traditional approaches. The study reported sought to demonstrate the potential for using (137)Cs measurements to assess the influence of soil erosion and redistribution on soil properties (particle size composition, total C, macronutrients N, P, K and Mg, micronutrients Mn, Mo, Fe, Cu and Zn and other elements, including Ti and As). (137)Cs measurements undertaken on 52 soil cores collected within a 7 ha cultivated field located near Colebrooke in Devon, UK were used to establish the magnitude and spatial pattern of medium-term soil redistribution rates within the field. The soil redistribution rates documented for the individual sampling points within the field ranged from an erosion rate of -12.9 t ha(-1) yr(-1) to a deposition rate of 19.2 t ha(-1) yr(-1). Composite samples of surface soil (0-5 cm) were collected immediately adjacent to each coring point and these samples were analysed for a range of soil properties. Individual soil properties associated with these samples showed significant variability, with CV values generally lying in the range 10-30%. The relationships between the surface soil properties and the soil redistribution rate were analysed. This analysis demonstrated statistically significant relationships between some soil properties (total phosphorus, % clay, Ti and As) and the soil redistribution rate, but for

  11. Using 137Cs measurements to investigate the influence of erosion and soil redistribution on soil properties

    International Nuclear Information System (INIS)

    Du, P.; Walling, D.E.

    2011-01-01

    Information on the interaction between soil erosion and soil properties is an important requirement for sustainable management of the soil resource. The relationship between soil properties and the soil redistribution rate, reflecting both erosion and deposition, is an important indicator of this interaction. This relationship is difficult to investigate using traditional approaches to documenting soil redistribution rates involving erosion plots and predictive models. However, the use of the fallout radionuclide 137 Cs to document medium-term soil redistribution rates offers a means of overcoming many of the limitations associated with traditional approaches. The study reported sought to demonstrate the potential for using 137 Cs measurements to assess the influence of soil erosion and redistribution on soil properties (particle size composition, total C, macronutrients N, P, K and Mg, micronutrients Mn, Mo, Fe, Cu and Zn and other elements, including Ti and As). 137 Cs measurements undertaken on 52 soil cores collected within a 7 ha cultivated field located near Colebrooke in Devon, UK were used to establish the magnitude and spatial pattern of medium-term soil redistribution rates within the field. The soil redistribution rates documented for the individual sampling points within the field ranged from an erosion rate of -12.9 t ha -1 yr -1 to a deposition rate of 19.2 t ha -1 yr -1 . Composite samples of surface soil (0-5 cm) were collected immediately adjacent to each coring point and these samples were analysed for a range of soil properties. Individual soil properties associated with these samples showed significant variability, with CV values generally lying in the range 10-30%. The relationships between the surface soil properties and the soil redistribution rate were analysed. This analysis demonstrated statistically significant relationships between some soil properties (total phosphorus, % clay, Ti and As) and the soil redistribution rate, but for most

  12. Plant species influence on soil C after afforestation of Mediterranean degraded soils

    Science.gov (United States)

    Dominguez, Maria T.; García-Vargas, Carlos; Madejón, Engracia; Marañón, Teodoro

    2015-04-01

    Increasing C sequestration in terrestrial ecosystems is one of the main current environmental challenges to mitigate climate change. Afforestation of degraded and contaminated lands is one of the key strategies to achieve an increase in C sequestration in ecosystems. Plant species differ in their mechanisms of C-fixation, C allocation into different plant organs, and interaction with soil microorganisms, all these factors influencing the dynamics of soil C following the afforestation of degraded soils. In this work we examine the influence of different woody plant species on soil C dynamics in degraded and afforested Mediterranean soils. The soils were former agricultural lands that were polluted by a mining accident and later afforested with different native plant species. We analysed the effect of four of these species (Olea europaea var. sylvestris Brot., Populus alba L., Pistacia lentiscus L. and Retama sphaerocarpa (L.) Boiss.) on different soil C fractions, soil nutrient availability, microbial activity (soil enzyme activities) and soil CO2 fluxes 15 years after the establishment of the plantations. Results suggest that the influence of the planted trees and shrubs is still limited, being more pronounced in the more acidic and nutrient-poor soils. Litter accumulation varied among species, with the highest C accumulated in the litter under the deciduous species (Populus alba L.). No differences were observed in the amount of total soil organic C among the studied species, or in the concentrations of phenols and sugars in the dissolved organic C (DOC), which might have indicated differences in the biodegradability of the DOC. Microbial biomass and activity was highly influenced by soil pH, and plant species had a significant influence on soil pH in the more acidic site. Soil CO2 fluxes were more influenced by the plant species than total soil C content. Our results suggest that changes in total soil C stocks after the afforestation of degraded Mediterranean

  13. Time as An Important Soil-Forming Factor Influencing Modern and Ancient Magnetic Susceptibility Enhancement Along the Delaware River Valley, USA

    Science.gov (United States)

    Stinchcomb, G. E.; Peppe, D. J.; Driese, S. G.

    2011-12-01

    Magnetic susceptibility is an increasingly popular low-cost method for rapidly assessing paleoclimate and paleoenvironmental impact on buried soils. The goal of this study is to determine the primary influence(s) on soil magnetic susceptibility along floodplain, terrace and upland soils in the middle Delaware River Valley, USA, using environmental magnetic, pedologic, and stratigraphic techniques. Two-hundred thirty samples were collected from age-constrained sandy, quartz-rich, floodplain, terrace, and upland soils (Entisols, Inceptisols). A Kruskal-Wallis (K-W) and post-hoc Tukey-Kramer (T-K) (α=0.05) multiple comparisons analysis on 176 mass-specific low-field susceptibility (Xlf) assays show that A and B horizons are magnetically enhanced compared to C and E horizons (ptesting show that Xlf results, when grouped by floodplain-terrace designation (i.e., chronofunction) are significantly different (p<0.0001). The older T3 terrace and upland Xlf values (0.34±0.14 10^-6 m^3 kg^-1) are greater than the younger T2 terrace (0.18±0.06 10^-6 m^3 kg^-1) values, which are greater than modern floodplain (0.09±0.01 10^-6 m^3 kg^-1) Xlf values. These data suggest that longer intervals of soil formation enhance the Χlf value. This hypothesis is further supported when 159 Xlf values are plotted vs. age for the entire Holocene. A locally-weighted regression smoothing curve (LOESS) shows two distinct intervals of magnetic enhancement during previously established dry intervals, the early and late-middle Holocene. We hypothesize that prolonged drought during the early and middle Holocene reduced flood frequency and magnitude and the likelihood of soil burial, resulting in longer soil forming intervals and higher Xlf values. Although precipitation influences the Xlf signature, the results from this study suggest that the magnetic susceptibility values of well-drained buried floodplain soils along the Delaware River Valley are partly a function of time.

  14. Dynamical soil-structure interactions: influence of soil behaviour nonlinearities

    International Nuclear Information System (INIS)

    Gandomzadeh, Ali

    2011-01-01

    the soil and the response of the soil-structure system. Through these parametric studies we show that depending on the soil properties, frequency content of the soil response could change significantly due to the soil nonlinearity. The peaks of the transfer function between free field and outcropping responses shift to lower frequencies and amplification happens at this frequency range. Amplification reduction for the high frequencies and even de-amplification may happen for high level input motions. These changes influence the structural response. We show that depending on the combination of the fundamental frequency of the structure and the the natural frequency of the soil, the effect of soil-structure interaction could be significant or negligible. However, the effect of structure weight and rocking of the superstructure could change the results. Finally, the basin of Nice is used as an example of wave propagation on a heterogeneous nonlinear media and dynamic soil-structure interaction. The basin response is strongly dependent on the combination of soil nonlinearity, topographic effects and impedance contrast between soil layers. For the selected structures and soil profiles of this work, the performed numerical simulations show that the shift of the fundamental frequency is not a good index to discriminate linear from nonlinear soil behavior. (author)

  15. Factors Influencing Farmers’ Adoption of Soil and Water Control Technology (SWCT in Keita Valley, a Semi-Arid Area of Niger

    Directory of Open Access Journals (Sweden)

    Boureima Yacouba Karidjo

    2018-01-01

    Full Text Available The AderDoutchiMaggia in Niger, as with other Sahelian zones, undergoes a process of climatic deterioration, which combines with the growing social and economic needs of the increasing population and causes a general economic crisis. Land degradation due to biophysical factors requires that priority action be given to land reclamation and soil conservation and to activities intended to increase agricultural production. This paper takes a look at socio-economic and established factors affecting the adoption of soil and water control technology (SWCT in Keita valley, a semi-arid area in the central of Niger. Well-designed questionnaire survey on key agents was used to gather the indispensable data from farm ménages. The binary dichotomous logistic regression model prognosticated six factors to be affecting the adoption of soil and water control technology in Keita. These variables cover the gender of the respondent, age of the household’s head, income evolution within the family, small craft referring to off farm income, training provide by local institutions, use of credit and, possession of full rights on land and its resources. The results revealed that diffusion of adoption from local organized community is a good alternative to increase the adoption of soil and water control technology in Keita valley agriculture system in Niger. Researchers and policy makers should conceive proper strategies and agenda reflecting the farmers’ interest, position and restriction in advocating new technologies for greater assumption and adoption by the farmers.

  16. Environmental factors influencing the structural dynamics of soil microbial communities during assisted phytostabilization of acid-generating mine tailings: a mesocosm experiment.

    Science.gov (United States)

    Valentín-Vargas, Alexis; Root, Robert A; Neilson, Julia W; Chorover, Jon; Maier, Raina M

    2014-12-01

    Compost-assisted phytostabilization has recently emerged as a robust alternative for reclamation of metalliferous mine tailings. Previous studies suggest that root-associated microbes may be important for facilitating plant establishment on the tailings, yet little is known about the long-term dynamics of microbial communities during reclamation. A mechanistic understanding of microbial community dynamics in tailings ecosystems undergoing remediation is critical because these dynamics profoundly influence both the biogeochemical weathering of tailings and the sustainability of a plant cover. Here we monitor the dynamics of soil microbial communities (i.e. bacteria, fungi, archaea) during a 12-month mesocosm study that included 4 treatments: 2 unplanted controls (unamended and compost-amended tailings) and 2 compost-amended seeded tailings treatments. Bacterial, fungal and archaeal communities responded distinctively to the revegetation process and concurrent changes in environmental conditions and pore water chemistry. Compost addition significantly increased microbial diversity and had an immediate and relatively long-lasting buffering-effect on pH, allowing plants to germinate and thrive during the early stages of the experiment. However, the compost buffering capacity diminished after six months and acidification took over as the major factor affecting plant survival and microbial community structure. Immediate changes in bacterial communities were observed following plant establishment, whereas fungal communities showed a delayed response that apparently correlated with the pH decline. Fluctuations in cobalt pore water concentrations, in particular, had a significant effect on the structure of all three microbial groups, which may be linked to the role of cobalt in metal detoxification pathways. The present study represents, to our knowledge, the first documentation of the dynamics of the three major microbial groups during revegetation of compost

  17. Mobility and retention of micronutrients in soil : Part III. Investigation on the influence of various external factors, NPK-fertilizers and soil amending agents on the mobility and retention of manganese

    International Nuclear Information System (INIS)

    Das, S.K.; Santikari, A.K.; Banerji, K.C.

    1980-01-01

    Investigations on the mobility and retention of manganese through Sindri red sandy clay loam of pH 7.4 and Ranchi clay loam of pH 5.6 have been carried out using the radiotracer 54 Mn. The vertical distribution of manganese in these soils showed almost sharp fall upto a depth of 12 to 14 cm and thereafter it tended to attain the saturation. Variations have been marked in the degrees of manganese retention at the top surface layers of the concerned soils. Influence of various NPK fertilizers and soil amending agents, at various application levels, have been studied on the mobility, retention and leaching loss of manganese in the prementioned soils. Marked variations have been recorded and discussed. (author)

  18. Soil properties influence kinetics of soil acid phosphatase in response to arsenic toxicity.

    Science.gov (United States)

    Wang, Ziquan; Tan, Xiangping; Lu, Guannan; Liu, Yanju; Naidu, Ravi; He, Wenxiang

    2018-01-01

    Soil phosphatase, which plays an important role in phosphorus cycling, is strongly inhibited by Arsenic (As). However, the inhibition mechanism in kinetics is not adequately investigated. In this study, we investigated the kinetic characteristics of soil acid phosphatase (ACP) in 14 soils with varied properties, and also explored how kinetic properties of soil ACP changed with different spiked As concentrations. The results showed that the Michaelis constant (K m ) and maximum reaction velocity (V max ) values of soil ACP ranged from 1.18 to 3.77mM and 0.025-0.133mMh -1 in uncontaminated soils. The kinetic parameters of soil ACP in different soils changed differently with As contamination. The K m remained unchanged and V max decreased with increase of As concentration in most acid and neutral soils, indicating a noncompetitive inhibition mechanism. However, in alkaline soils, the K m increased linearly and V max decreased with increase of As concentration, indicating a mixed inhibition mechanism that include competitive and noncompetitive. The competitive inhibition constant (K ic ) and noncompetitive inhibition constant (K iu ) varied among soils and ranged from 0.38 to 3.65mM and 0.84-7.43mM respectively. The inhibitory effect of As on soil ACP was mostly affected by soil organic matter and cation exchange capacity. Those factors influenced the combination of As with enzyme, which resulted in a difference of As toxicity to soil ACP. Catalytic efficiency (V max /K m ) of soil ACP was a sensitive kinetic parameter to assess the ecological risks of soil As contamination. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Human factors influencing decision making

    OpenAIRE

    Jacobs, Patricia A.

    1998-01-01

    This report supplies references and comments on literature that identifies human factors influencing decision making, particularly military decision making. The literature has been classified as follows (the classes are not mutually exclusive): features of human information processing; decision making models which are not mathematical models but rather are descriptive; non- personality factors influencing decision making; national characteristics influencing decision makin...

  20. Soil-plant transfer factors in forest ecosystems

    International Nuclear Information System (INIS)

    Strebl, F.; Gerzabek, M.H.

    1995-04-01

    Within scope of an extended study about 137 Cs behaviour in forest ecosystems several parameters were found to influence soil-plant transfer factors. TF-values of different plant species cover a range of two magnitudes. This is partly due to variations in rooting depth of plants and specific physiological adaptations of nutrient supply. Perrenial plants like trees (Picea abies) and dwarf shrubs (Vaccinium myrtillus) showed a distinct age - dependency of 137 Cs - transfer factors. In young plant parts caesium concentration is higher than in old, more signified twigs. A correlation analysis of physico-chemical soil parameters and TF-values to forest vegetation showed, that soil organic matter, especially the degree of humification and the ratio between extractable fulvic to humic acids are important influencing factors of 137 Cs transfer from forest soils to plants. (author)

  1. Abiotic factors influencing tropical dry forests regeneration

    Directory of Open Access Journals (Sweden)

    Ceccon Eliane

    2006-01-01

    Full Text Available Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.

  2. Variability of soil-to-crop transfer factor

    International Nuclear Information System (INIS)

    Uchida, Shigeo; Kamada, Hiroshi; Yokosuka, Setsuko; Ohmomo, Yoichiro

    1987-01-01

    Many European countries have nuclear facilities in inland areas, where extremely low level radioactive waste liquid is discharged to rivers. In those nations, therefore, many studies have been made oncerning the transfer of radioisotopes into plants. In Japan, greater attention has been attracted to such radioisotope transfer into plants and then into human bodies. Thus the present report reviews various studies on this issue. The key parameter for this process is the transfer factor (also called concentration factor, coefficient or ratio). The factor largely depends on various other factors including the characteristics of different nuclides, properties of soil (pH, oxidation-reduction potential, grain size distribution, contents of clay minerals, contents of organic matters, water content, etc.), characteristics of crops and cultivation conditions. It has been reported that I is absorbed by plants more rapidly than IO 3 . Of the various soil parameters, the pH of soil has the greatest effect on the transfer factor. Soil is mostly alkaline in Europe and America while acid soil account for a great part in Japan, suggesting that the transfer factor would be greater in Japan. The total potassium content in soil has the second largest effect on the factor. Radioactive iodine has shown to be transferred into soy beans and spinach 30 times more rapidly than into fruit vegetables. The oxidation-reduction potential also has a significant influence on the transfer factor. (Nogami, K.)

  3. Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil

    OpenAIRE

    Tejeda Agredano, M. C.; Gallego, Sara; Vila, Joaquim; Ortega Calvo, J. J.; Cantos, Manuel

    2013-01-01

    Reduced bioavailability to soil microorganisms is probably the most limiting factor in the bioremediation of polycyclic aromatic hydrocarbons PAH-polluted soils. We used sunflowers planted in pots containing soil to determine the influence of the rhizosphere on the ability of soil microbiota to reduce PAH levels. The concentration of total PAHs decreased by 93% in 90 days when the contaminated soil was cultivated with sunflowers, representing an improvement of 16% compared to contaminated soi...

  4. Factors influencing plant invasiveness

    Science.gov (United States)

    Yvette Ortega; Dean Pearson

    2009-01-01

    Invasiveness of spotted knapweed and biological control agents. Dean and Yvette are examining the influence of drought on the invasiveness of spotted knapweed (Centaurea maculosa) and its susceptibility to herbivory by biological control agents. In collaboration with the University of Montana and Forest Health Protection, researchers have constructed 150...

  5. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey R.; Harden, Jennifer W.; Maher, Kate

    2014-01-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  6. Influence of spatially dependent, modeled soil carbon emission factors on life-cycle greenhouse gas emissions of corn and cellulosic ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Zhangcai [Energy Systems Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Dunn, Jennifer B. [Energy Systems Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Kwon, Hoyoung [Environment and Production Technology Division, International Food Policy Research Institute, 2033 K St. NW Washington DC 20006 USA; Mueller, Steffen [Energy Resources Center, University of Illinois at Chicago, 1309 South Halsted Street Chicago IL 60607 USA; Wander, Michelle M. [Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue Urbana IL 61801 USA

    2016-03-03

    Converting land to biofuel feedstock production incurs changes in soil organic carbon (SOC) that can influence biofuel life-cycle greenhouse gas (GHG) emissions. Estimates of these land use change (LUC) and life-cycle GHG emissions affect biofuels’ attractiveness and eligibility under a number of renewable fuel policies in the U.S. and abroad. Modeling was used to refine the spatial resolution and depth-extent of domestic estimates of SOC change for land (cropland, cropland pasture, grasslands, and forests) conversion scenarios to biofuel crops (corn, corn stover, switchgrass, Miscanthus, poplar, and willow). In most regions, conversions from cropland and cropland pasture to biofuel crops led to neutral or small levels of SOC sequestration, while conversion of grassland and forest generally caused net SOC loss. Results of SOC change were incorporated into the Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (GREET) model to assess their influence on life-cycle GHG emissions for the biofuels considered. Total LUC GHG emissions (g CO2eq MJ-1) were 2.1–9.3 for corn, -0.7 for corn stover, -3.4–12.9 for switchgrass, and -20.1–-6.2 for Miscanthus; these varied with SOC modeling assumptions applied. Extending soil depth from 30 to 100cm affected spatially-explicit SOC change and overall LUC GHG emissions; however the influence on LUC GHG emissions estimates were less significant in corn and corn stover than cellulosic feedstocks. Total life-cycle GHG emissions (g CO2eq MJ-1, 100cm) were estimated to be 59–66 for corn ethanol, 14 for stover ethanol, 18-26 for switchgrass ethanol, and -0.6–-7 for Miscanthus ethanol.

  7. Potential factors affecting accumulation of unsupported 210Pb in soil

    International Nuclear Information System (INIS)

    Mihailović, Aleksandra; Vučinić Vasić, Milica; Todorović, Nataša; Hansman, Jan; Vasin, Jovica; Krmar, Miodrag

    2014-01-01

    Airborne 210 Pb, daughter of 222 Rn, is frequently used as a tracer in different studies concerning atmospheric transport, sedimentation, soil erosion, dating, etc. Concentration of 210 Pb was measured in 40 soil samples collected in urban and industrial areas in order to get evidence of possible influence of some factors on accumulation of airborne 210 Pb in soil. Different soil properties such as the content of organic matter, free CaCO 3 , and available phosphorus (P 2 O 5 ) were measured to explore their possible correlation with the amount of 210 Pb. Special attention was given to the correlation between 210 Pb and stable lead accumulated in the soil. Several samples were taken near a battery manufacturer to check if extremely high concentrations of lead can affect the uptake of the airborne 210 Pb in soil. Soil samples were also taken at different depths to investigate the penetration of lead through the soil. - Highlights: • 210 Pb and 137 Cs were measured in samples of urban soil. • Organic matter, free CaCO 3 content, available phosphorus, and lead were measured in soil samples. • There is no statistically significant correlation between 210 Pb and lead, CaCO 3 and phosphorus. • A strong positive correlation between 210 Pb and organic matter was observed

  8. PRINCIPAL COMPONENT ANALYSIS OF FACTORS DETERMINING PHOSPHATE ROCK DISSOLUTION ON ACID SOILS

    Directory of Open Access Journals (Sweden)

    Yusdar Hilman

    2016-10-01

    Full Text Available Many of the agricultural soils in Indonesia are acidic and low in both total and available phosphorus which severely limits their potential for crops production. These problems can be corrected by application of chemical fertilizers. However, these fertilizers are expensive, and cheaper alternatives such as phosphate rock (PR have been considered. Several soil factors may influence the dissolution of PR in soils, including both chemical and physical properties. The study aimed to identify PR dissolution factors and evaluate their relative magnitude. The experiment was conducted in Soil Chemical Laboratory, Universiti Putra Malaysia and Indonesian Center for Agricultural Land Resources Research and Development from January to April 2002. The principal component analysis (PCA was used to characterize acid soils in an incubation system into a number of factors that may affect PR dissolution. Three major factors selected were soil texture, soil acidity, and fertilization. Using the scores of individual factors as independent variables, stepwise regression analysis was performed to derive a PR dissolution function. The factors influencing PR dissolution in order of importance were soil texture, soil acidity, then fertilization. Soil texture factors including clay content and organic C, and soil acidity factor such as P retention capacity interacted positively with P dissolution and promoted PR dissolution effectively. Soil texture factors, such as sand and silt content, soil acidity factors such as pH, and exchangeable Ca decreased PR dissolution.

  9. Experimental Study of Factors Affecting Soil Erodibility

    Science.gov (United States)

    Larionov, G. A.; Bushueva, O. G.; Gorobets, A. V.; Dobrovolskaya, N. G.; Kiryukhina, Z. P.; Krasnov, S. F.; Litvin, L. F.; Maksimova, I. A.; Sudnitsyn, I. I.

    2018-03-01

    The effect of different factors and preparation conditions of monofraction samples from the arable horizon of leached chernozem on soil erodibility and its relationship with soil tensile strength (STS) has been studied. The exposure of samples at 38°C reduces their erodibility by two orders of magnitude. The drying of samples, on the contrary, increases their erodibility. It has been shown that erodibility decreases during the experiment. It has been found that the inoculation of soil with yeast cultures ( Naganishia albida, Lipomyces tetrasporus) reliably increases the STS value in 1.5-1.9 times. The sterile soil is eroded more intensively than the unsterile soil: at 4.9 and 0.3 g/(m2 s), respectively. The drying of soil followed by wetting to the initial water content (30%) has no significant effect on the STS value in almost all experimental treatments.

  10. Soil-structure interaction Vol.3. Influence of ground water

    Energy Technology Data Exchange (ETDEWEB)

    Costantino, C J

    1986-04-01

    This study has been performed for the Nuclear Regulatory Commission (NRC) by the Structural Analysis Division of Brookhaven National Laboratory (BNL). The study was conducted during the fiscal year 1965 on the program entitled 'Benchmarking of Structural Engineering Problems' sponsored by NRC. The program considered three separate but complementary problems, each associated with the soil-structure interaction (551) phase of the seismic response analysis of nuclear plant facilities. The reports, all entitled Soil-Structure Interaction, are presented in three separate volumes, namely: Vol. 1 Influence of Layering by AJ Philippacopoulos, Vol. 2 Influence of Lift-Off by C.A. Miller, Vol. 3 Influence of Ground Water by C.J. Costantino. The two problems presented in Volumes 2 and 3 were conducted at the City University of New York (CUNY) under subcontract to BNL. This report, Volume 3 of the report, presents a summary of the first year's effort on the subject of the influence of foundation ground water on the SSI phenomenon. A finite element computer program was developed for the two-phased formulation of the combined soil-water problem. This formulation is based on the Biot dynamic equations of motion for both the solid and fluid phases of a typical soil. Frequency dependent interaction coefficients were generated for the two-dimensional plane problem of a rigid surface footing moving against a saturated linear soil. The results indicate that interaction coefficients are significantly modified as compared to the comparable values for a dry soil, particularly for the rocking mode of response. Calculations were made to study the impact of the modified interaction coefficients on the response of a typical nuclear reactor building. The amplification factors for a stick model placed atop a dry and saturated soil were computed. It was found that pore water caused the rocking response to decrease and translational response to increase over the frequency range of interest, as

  11. Factors Influencing of Social Conflict

    Directory of Open Access Journals (Sweden)

    Suwandi Sumartias

    2013-07-01

    Full Text Available Social conflicts that occur in several areas in Indonesia lately, one of them is caused by the weakness of law certainty. This is feared to threaten the integration of the Republic of Indonesia. This study aims to determine the factors that affect social conflict in Manis Lor village in Kuningan district. The method used the explanatory quantitative methods, the statistical test Path Analysis. The study population was a formal and informal community leaders (village chief, clergy, and youth, and the people who involved in a conflict in Manis Lor village Kuningan regency. The result shows a There is no significant influence between social identity factors with social conflict anarchist. b There is significant influence between socio-economic factors with social conflict anarchists. c There is no significant influence between the credibility factor anarchist leaders with social conflict. d There is no significant influence between the motive factor with anarchist social conflict. e There is significant influence between personality factors/beliefs with anarchist social conflict. f There is significant influence of behavioral factors anarchist communication with social conflict.

  12. Dissipation of sulfamethoxazole in pasture soils as affected by soil and environmental factors.

    Science.gov (United States)

    Srinivasan, Prakash; Sarmah, Ajit K

    2014-05-01

    The dissipation of sulfamethoxazole (SMO) antibiotic in three different soils was investigated through laboratory incubation studies. The experiments were conducted under different incubation conditions such as initial chemical concentration, soil depth, temperature, and with sterilisation. The results indicate that SMO dissipated rapidly in New Zealand pasture soils, and the 50% dissipation times (DT50) in Hamilton, Te Kowhai and Horotiu soils under non-sterile conditions were 9.24, 4.3 and 13.33 days respectively. During the incubation period for each sampling event the soil dehydrogenase activity (DHA) and the variation in microbial community were monitored thorough phospholipid fatty acid extraction analysis (PLFA). The DHA data correlated well with the dissipation rate constants of SMO antibiotic, an increase in the DHA activity resulted in faster antibiotic dissipation. The PLFA analysis was indicative of higher bacterial presence as compared to fungal community, highlighting the type of microbial community responsible for dissipation. The results indicate that with increasing soil depth, SMO dissipation in soil was slower (except for Horotiu) while with increase in temperature the antibiotic loss was faster, and was noticeable in all the soils. Both the degree of biological activity and the temperature of the soil influenced overall SMO dissipation. SMO is not likely to persist more than 5-6 months in all three soils suggesting that natural biodegradation may be sufficient for the removal of these contaminants from the soil. Its dissipation in sterile soils indicated abiotic factors such as strong sorption onto soil components to play a role in the dissipation of SMO. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Influence of mammal fossorial activity on the soil fermentative activity in conditions of metallurgical production

    Directory of Open Access Journals (Sweden)

    S. M. Kirienko

    2010-09-01

    Full Text Available Effect of mammal fossorial activity as an ecological factor of the soil genesis intensification is studied. Enzymatic activity of soil as its ability to demonstrate a catalytic effect for various compounds transformation is examined. Variability of soil urease activity in technogenic conditions with the participation of animals is shown. The positive influence of animals’ activity on the catalitic ability of the investigated soils was determined. The statistically significant characteristics which have an influence on the urease activity in soil are found out.

  14. Using {sup 137}Cs measurements to investigate the influence of erosion and soil redistribution on soil properties

    Energy Technology Data Exchange (ETDEWEB)

    Du, P. [School of Geography, Beijing Normal University, Beijing (China); Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Rennes Drive, Exeter, EX4 4RJ, Devon (United Kingdom); Walling, D.E., E-mail: d.e.walling@exeter.ac.u [Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Rennes Drive, Exeter, EX4 4RJ, Devon (United Kingdom)

    2011-05-15

    Information on the interaction between soil erosion and soil properties is an important requirement for sustainable management of the soil resource. The relationship between soil properties and the soil redistribution rate, reflecting both erosion and deposition, is an important indicator of this interaction. This relationship is difficult to investigate using traditional approaches to documenting soil redistribution rates involving erosion plots and predictive models. However, the use of the fallout radionuclide {sup 137}Cs to document medium-term soil redistribution rates offers a means of overcoming many of the limitations associated with traditional approaches. The study reported sought to demonstrate the potential for using {sup 137}Cs measurements to assess the influence of soil erosion and redistribution on soil properties (particle size composition, total C, macronutrients N, P, K and Mg, micronutrients Mn, Mo, Fe, Cu and Zn and other elements, including Ti and As). {sup 137}Cs measurements undertaken on 52 soil cores collected within a 7 ha cultivated field located near Colebrooke in Devon, UK were used to establish the magnitude and spatial pattern of medium-term soil redistribution rates within the field. The soil redistribution rates documented for the individual sampling points within the field ranged from an erosion rate of -12.9 t ha{sup -1} yr{sup -1} to a deposition rate of 19.2 t ha{sup -1} yr{sup -1}. Composite samples of surface soil (0-5 cm) were collected immediately adjacent to each coring point and these samples were analysed for a range of soil properties. Individual soil properties associated with these samples showed significant variability, with CV values generally lying in the range 10-30%. The relationships between the surface soil properties and the soil redistribution rate were analysed. This analysis demonstrated statistically significant relationships between some soil properties (total phosphorus, % clay, Ti and As) and the soil

  15. Factors influencing women's decisions to purchase specific ...

    African Journals Online (AJOL)

    aimed at identifying the factors that influence women's decisions to purchase specific .... influence of all the factors influencing their decision to purchase a selected .... one free” promotions seemed to have had the greatest influence on this ...

  16. Influence of temperature and organic matter content on soil respiration in a deciduous oak forest

    Directory of Open Access Journals (Sweden)

    Zsolt Kotroczó

    2014-12-01

    Full Text Available The increasing temperature enhances soil respiration differently depend on different conditions (soil moisture, soil organic matter, the activity of soil microbes. It is an essential factor to predicting the effect of climate change on soil respiration. In a temperate deciduous forest (North-Hungary we added or removal aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture and soil temperature. Soil CO2 efflux was measured at each plot using chamber based soil respiration measurements. We determined the temperature sensitivity of soil respiration. The effect of doubled litter was less than the effect of removal. We found that temperature was more influential in the control of soil respiration than soil moisture in litter removal treatments, particularly in the wetter root exclusion treatments (NR and NI (R2: 0.49-0.61. Soil moisture (R2: 0.18-0.24 and temperature (R2: 0.18-0.20 influenced soil respiration similarly in treatments, where soil was drier (Control, Double Litter, Double Wood. A significantly greater increase in temperature induced higher soil respiration were significantly higher (2-2.5-fold in root exclusion treatments, where soil was wetter throughout the year, than in control and litter addition treatments. The highest bacterial and fungal count was at the DL treatment but the differences is not significant compared to the Control. The bacterial number at the No Litter, No Root, No Input treatment was significantly lower at the Control. Similar phenomenon can be observed at the fungal too, but the differences are not significant. The results of soil respiration suggest that the soil aridity can reduce soil respiration increases with the temperature increase. Soil bacterial and fungal count results show the higher organic matter content and soil surface cover litter favors the activity.

  17. FACTORS INFLUENCING SECOND LANGUAGE ACQUISITION

    Directory of Open Access Journals (Sweden)

    Siti Khasinah

    2014-05-01

    Full Text Available Motivation, attitude, age, intelligence, aptitude, cognitive style, and personality are considered as factors that greatly influence someone in the process of his or her second language acquisition. Experts state that those factors give a more dominant contribution in SLA to learners variedly, depend on who the learners are, their age, how they behave toward the language, their cognitive ability, and also the way they learn.

  18. Factors influencing bone scan quality

    International Nuclear Information System (INIS)

    Adams, F.G.; Shirley, A.W.

    1983-01-01

    A reliable subjective method of assessing bone scan quality is described. A large number of variables which theoretically could influence scan quality were submitted to regression and factor analysis. Obesity, age, sex and abnormality of scan were found to be significant but weak variables. (orig.)

  19. Temporal variations and spatial distributions of heavy metals in a wastewater-irrigated soil-eggplant system and associated influencing factors.

    Science.gov (United States)

    Ai, Shiwei; Liu, Bailin; Yang, Ying; Ding, Jian; Yang, Wenzhi; Bai, Xiaojuan; Naeem, Sajid; Zhang, Yingmei

    2018-05-30

    Heavy metal pollution in farmlands is highly concerned as crops' easy-uptake of heavy metal can ultimately affect consumers. In order to offer suggestions on cultivating safe quality vegetable, specifically eggplant which is widely consumed for its nutritional value and antioxidant activity, a field study was undertaken to investigate the temporal variations and spatial distributions of heavy metals in a wastewater-irrigated soil-eggplant system. In the present study, eggplants were planted in the farmlands of Weichuan village (WC) (relatively unpolluted field), Liangzhuang village (LZ) (moderately polluted field) and Minqin village (MQ) (seriously polluted field) to elucidate their temporal uptake processes of heavy metals described by the sigmoid model. Eggplant tissues from severely polluted farmlands were found with higher heavy metal concentrations and lower yields compared with other two groups. What is more, 25 farmlands along the Dongdagou stream (heavy metals polluted stream) were chosen to analyze the spatial distribution of heavy metals in soils and eggplants. Heavy metal concentrations in eggplants decreased with the decline of heavy metal concentrations in soil from upstream (pollution source) to downstream. Moreover, several methods were employed to assess bioavailability of heavy metals in soils. All the bioavailable heavy metals were found in linear positive correlations with heavy metal concentrations. Meanwhile, linear correlations were found between heavy metals in soils and eggplants. At last, redundancy analysis was used to investigate the effects of soil properties (pH, organic matter and texture of soils) and heavy metals on eggplants' uptake. The results indicated that soil heavy metals had a dominant impact on their accumulations in eggplant fruit, with a variance contribution of 78.0%, while soil properties had a regulatory effect, with a variance contribution of 5.2%. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. What factors influence mitigative capacity?

    International Nuclear Information System (INIS)

    Winkler, Harald; Baumert, Kevin; Blanchard, Odile; Burch, Sarah; Robinson, John

    2007-01-01

    This article builds on Yohe's seminal piece on mitigative capacity, which elaborates 'determinants' of mitigative capacity, also reflected in the IPCC's third assessment report. We propose a revised definition, where mitigative capacity is a country's ability to reduce anthropogenic greenhouse gas emissions or enhance natural sinks. By 'ability' we mean skills, competencies, fitness, and proficiencies that a country has attained which can contribute to GHG emissions mitigation. A conceptual framework is proposed, linking mitigative capacity to a country's sustainable development path, and grouping the factors influencing mitigative capacity into three main sets: economic factors, institutional ones, and technology. Both quantitative and qualitative analysis of factors is presented, showing how these factors vary across countries. We suggest that it is the interplay between the three economic factors-income, abatement cost and opportunity cost-that shape mitigative capacity. We find that income is an important economic factor influencing mitigative capacity, while abatement cost is important in turning mitigative capacity into actual mitigation. Technology is a critical mitigative capacity, including the ability to absorb existing climate-friendly technologies or to develop innovative ones. Institutional factors that promote mitigative capacity include the effectiveness of government regulation, clear market rules, a skilled work force and public awareness. We briefly investigate such as high abatement cost or lack of political willingness that prevent mitigative capacity from being translated into mitigation

  1. Soil Plant and plant mammal transfer factors

    NARCIS (Netherlands)

    de Nijs ACM; Vermeire TG

    1990-01-01

    In order to assess the lifetime hazard of ingestion exposure of man to new substances, the RIVM Assessment System for New Substances links environmental concentrations in water and soil to human exposure applying transfer factors. This report discusses indirect human exposure to new substances via

  2. The Influence of Soil Particle on Soil Condensation Water

    OpenAIRE

    Hou Xinwei; Chen Hao; Li Xiangquan; Cui Xiaomei; Liu Lingxia; Wang Zhenxing

    2013-01-01

    The experiment results showed that the indoor experiment formed from the volume of soil hygroscopic water increased gradually with decreasing size of soil particles. In the outdoor experiments, the results showed that the formed condensation water in medium sand was greater than it was in fine sand; the soil hot condensation water was mainly formed in the top layer of soil between 0-5 cm. We also found that covering the soil surface with stones can increase the volume of formed soil condensat...

  3. Influence of 15N enrichment on the net isotopic fractionation factor during the reduction of nitrate to nitrous oxide in soil

    DEFF Research Database (Denmark)

    Mathieu, O.; Levegue, J.; Henault, C.

    2007-01-01

    Nitrous oxide, a greenhouse gas, is mainly emitted from soils during the denitrification process. Nitrogen stable-isotope investigations can help to characterise the N(2)O source and N(2)O production mechanisms. The stable-isotope approach is increasingly used with (15)N natural abundance...

  4. Influence of soil texture on the distribution and availability of 238U, 230Th, and 226Ra in soils

    International Nuclear Information System (INIS)

    Blanco Rodriguez, P.; Vera Tome, F.; Lozano, J.C.; Perez-Fernandez, M.A.

    2008-01-01

    The influence of soil texture on the distribution and availability of 238 U, 230 Th, and 226 Ra in soils was studied in soil samples collected at a rehabilitated uranium mine located in the Extremadura region in south-west Spain. The activity concentration (Bq kg -1 ) in the soils ranged from 60 to 750 for 238 U, from 60 to 260 for 230 Th, and from 70 to 330 for 226 Ra. The radionuclide distribution was determined in three soil fractions: coarse sand (0.5-2 mm), medium-fine sand (0.067-0.5 mm), and silt and clay ( 238 U, 230 Th, and 226 Ra between the activity concentration per fraction and the total activity concentration in the bulk soil. Thus, from the determination of the activity concentration in the bulk soil, one could estimate the activity concentration in each fraction. Correlations were also found for 238 U and 226 Ra between the labile activity concentration in each fraction and the total activity concentration in bulk soil. Assuming that there is some particle-size fraction that predominates in the process of soil-to-plant transfer, the parameters obtained in this study should be used as correction factors for the transfer factors determined from the bulk soil in previous studies

  5. [Influences of biochar and nitrogen fertilizer on soil nematode assemblage of upland red soil].

    Science.gov (United States)

    Lu, Yan-yan; Wang, Ming-wei; Chen, Xiao-vun; Liu, Man-qiang; Chen, Xiao-min; Cheng, Yan-hong; Huang, Qian-ru; Hu, Feng

    2016-01-01

    The use of biochar as soil remediation amendment has received more and more concerns, but little attention has been paid to its effect on soil fauna. Based on the field experiment in an upland red soil, we studied the influences of different application rates of biochar (0, 10, 20, 30, 40 t · hm⁻²) and nitrogen fertilizer (60, 90, 120 kg N · hm⁻²) on soil basic properties and nematode assemblages during drought and wet periods. Our results showed that the biochar amendment significantly affect soil moisture and pH regardless of drought or wet period. With the increasing of biochar application, soil pH significantly increased, while soil moisture increased first and then decreased. Soil microbial properties (microbial biomass C, microbial biomass N, microbial biomass C/N, basal respiration) were also significantly affected by the application of biochar and N fertilizer. Low doses of biochar could stimulate the microbial activity, while high doses depressed microbial activity. For example, averaged across different N application rates, biochar amendment at less than 30 t · hm⁻² could increase microbial activity in the drought and wet periods. Besides, the effects of biochar also depended on wet or drought period. When the biochar application rate higher than 30 t · hm⁻², the microbial biomass C was significantly higher in the drought period than the control, but no differences were observed in the wet period. On the contrary, microbial biomass N showed a reverse pattern. Dissolved organic matter and mineral N were affected by biochar and N fertilizer significantly in the drought period, however, in the wet period they were only affected by N fertilizer rather than biochar. There was significant interaction between biochar and N fertilizer on soil nematode abundance and nematode trophic composition independent of sampling period. Combined high doses of both biochar and N fertilization promoted soil nematode abundance. Moreover, the biochar amendment

  6. The Validation Of Influence Factors To DDT Concentration In Soil; Validasi Faktor-Faktor Yang Berpengaruh Terhadap Kadar DDT Di Dalam Tanah

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, Zainul; Poernomo, Herry [Center for Research and Development of Advanced Technology, National Nuclear Energy Agency, Serpong (Indonesia)

    2000-09-01

    Determination concentration of DDT in humidified land's and rising intensity has been done. The amount of natural soil was filled in poliethylene tube, and the amount of humadified soil was filled in order poliethylene tube. The solution of DDT-C sub.14 with volume of 10 ml and activity of 10 muCi was increased in those tube respectively, the latter it was resident for many time under shine. Sample of soil was took first week to sixthweek, it was crushed to reach homogenous, then it was counted by liquid scintillation counter. The experiment result indicated that the DDT content in the unilluminated soil for 1 week is < 0.1 ppb, for 2 week is 0.19 n 0.01 ppb, for 3 week is 1.95 n 0.32 ppb, for 4 week is 14.07 n 0.14 ppb, for 5 week is 3.67 n 0.21 ppb and for 6 week is 2.28 n 0.09 ppb. The DDT content in the humidified soil without sun illumination for 1 week is 0.25 n 0.07 ppb, for 2 week is 6.34 n 0.19 ppb, for 3 week is 9.33 n 0.80 ppb, for 4 week is 12.36 n 0.17 ppb, for 5 week is 4.58 n 0.15 ppb and for 6 week is 2.01 n 0.55 ppb. The DDT content in the natural soil illuminated by VIS for 1 week is 0.74 n 0.08 ppb, for 2 week is 7.48 n 0.14 ppb, for 3 week is 4.06 n 0.28 ppb, for 4 week is 13.16 n 0.20 ppb, for 5 week is 5.00 n 0.70 ppb and for 6 week is 2.03 n 0.03 ppb.

  7. College factors that influence drinking.

    Science.gov (United States)

    Presley, Cheryl A; Meilman, Philip W; Leichliter, Jami S

    2002-03-01

    The purpose of this article is to examine the aspects of collegiate environments, rather than student characteristics, that influence drinking. Unfortunately, the existing literature is scant on this topic. A literature review of articles primarily published within the last 10 years, along with some earlier "landmark" studies of collegiate drinking in the United States, was conducted to determine institutional factors that influence the consumption of alcohol. In addition, a demonstration analysis of Core Alcohol and Drug Survey research findings was conducted to further elucidate the issues. Several factors have been shown to relate to drinking: (1) organizational property variables of campuses, including affiliations (historically black institutions, women's institutions), presence of a Greek system, athletics and 2- or 4-year designation; (2) physical and behavioral property variables of campuses, including type of residence, institution size, location and quantity of heavy episodic drinking; and (3) campus community property variables, including pricing and availability and outlet density. Studies, however, tend to look at individual variables one at a time rather than in combination (multivariate analyses). Some new analyses, using Core Alcohol and Drug Survey data sets, are presented as examples of promising approaches to future research. Given the complexities of campus environments, it continues to be a challenge to the field to firmly establish the most compelling institutional and environmental factors relating to high-risk collegiate drinking.

  8. Factors Influencing Healthcare Service Quality

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Mosadeghrad

    2014-07-01

    Full Text Available Background The main purpose of this study was to identify factors that influence healthcare quality in the Iranian context. Methods Exploratory in-depth individual and focus group interviews were conducted with 222 healthcare stakeholders including healthcare providers, managers, policy-makers, and payers to identify factors affecting the quality of healthcare services provided in Iranian healthcare organisations. Results Quality in healthcare is a production of cooperation between the patient and the healthcare provider in a supportive environment. Personal factors of the provider and the patient, and factors pertaining to the healthcare organisation, healthcare system, and the broader environment affect healthcare service quality. Healthcare quality can be improved by supportive visionary leadership, proper planning, education and training, availability of resources, effective management of resources, employees and processes, and collaboration and cooperation among providers. Conclusion This article contributes to healthcare theory and practice by developing a conceptual framework that provides policy-makers and managers a practical understanding of factors that affect healthcare service quality.

  9. Influence of Elevation Data Resolution on Spatial Prediction of Colluvial Soils in a Luvisol Region.

    Directory of Open Access Journals (Sweden)

    Vít Penížek

    Full Text Available The development of a soil cover is a dynamic process. Soil cover can be altered within a few decades, which requires updating of the legacy soil maps. Soil erosion is one of the most important processes quickly altering soil cover on agriculture land. Colluvial soils develop in concave parts of the landscape as a consequence of sedimentation of eroded material. Colluvial soils are recognised as important soil units because they are a vast sink of soil organic carbon. Terrain derivatives became an important tool in digital soil mapping and are among the most popular auxiliary data used for quantitative spatial prediction. Prediction success rates are often directly dependent on raster resolution. In our study, we tested how raster resolution (1, 2, 3, 5, 10, 20 and 30 meters influences spatial prediction of colluvial soils. Terrain derivatives (altitude, slope, plane curvature, topographic position index, LS factor and convergence index were calculated for the given raster resolutions. Four models were applied (boosted tree, neural network, random forest and Classification/Regression Tree to spatially predict the soil cover over a 77 ha large study plot. Models training and validation was based on 111 soil profiles surveyed on a regular sampling grid. Moreover, the predicted real extent and shape of the colluvial soil area was examined. In general, no clear trend in the accuracy prediction was found without the given raster resolution range. Higher maximum prediction accuracy for colluvial soil, compared to prediction accuracy of total soil cover of the study plot, can be explained by the choice of terrain derivatives that were best for Colluvial soils differentiation from other soil units. Regarding the character of the predicted Colluvial soils area, maps of 2 to 10 m resolution provided reasonable delineation of the colluvial soil as part of the cover over the study area.

  10. Influence of Elevation Data Resolution on Spatial Prediction of Colluvial Soils in a Luvisol Region

    Science.gov (United States)

    Penížek, Vít; Zádorová, Tereza; Kodešová, Radka; Vaněk, Aleš

    2016-01-01

    The development of a soil cover is a dynamic process. Soil cover can be altered within a few decades, which requires updating of the legacy soil maps. Soil erosion is one of the most important processes quickly altering soil cover on agriculture land. Colluvial soils develop in concave parts of the landscape as a consequence of sedimentation of eroded material. Colluvial soils are recognised as important soil units because they are a vast sink of soil organic carbon. Terrain derivatives became an important tool in digital soil mapping and are among the most popular auxiliary data used for quantitative spatial prediction. Prediction success rates are often directly dependent on raster resolution. In our study, we tested how raster resolution (1, 2, 3, 5, 10, 20 and 30 meters) influences spatial prediction of colluvial soils. Terrain derivatives (altitude, slope, plane curvature, topographic position index, LS factor and convergence index) were calculated for the given raster resolutions. Four models were applied (boosted tree, neural network, random forest and Classification/Regression Tree) to spatially predict the soil cover over a 77 ha large study plot. Models training and validation was based on 111 soil profiles surveyed on a regular sampling grid. Moreover, the predicted real extent and shape of the colluvial soil area was examined. In general, no clear trend in the accuracy prediction was found without the given raster resolution range. Higher maximum prediction accuracy for colluvial soil, compared to prediction accuracy of total soil cover of the study plot, can be explained by the choice of terrain derivatives that were best for Colluvial soils differentiation from other soil units. Regarding the character of the predicted Colluvial soils area, maps of 2 to 10 m resolution provided reasonable delineation of the colluvial soil as part of the cover over the study area. PMID:27846230

  11. Measurement of soil lead bioavailability and influence of soil types and properties: A review.

    Science.gov (United States)

    Yan, Kaihong; Dong, Zhaomin; Wijayawardena, M A Ayanka; Liu, Yanju; Naidu, Ravi; Semple, Kirk

    2017-10-01

    Lead (Pb) is a widespread heavy metal which is harmful to human health, especially to young children. To provide a human health risk assessment that is more relevant to real conditions, Pb bioavailability in soils is increasingly employed in the assessment procedure. Both in vivo and in vitro measurements for lead bioavailability are available. In vivo models are time- consuming and expensive, while in vitro models are rapid, economic, reproducible, and reliable while involving more uncertainties. Uncertainties in various measurements create difficulties in accurately predicting Pb bioavailability, resulting in the unnecessary remediation of sites. In this critical review, we utilised available data from in vivo and in vitro studies to identify the key parameters influencing the in vitro measurements, and presented uncertainties existing in Pb bioavailability measurements. Soil type, properties and metal content are reported to influence lead bioavailability; however, the differences in methods for assessing bioavailability and the differences in Pb source limit one's ability to conduct statistical analyses on influences of soil factors on Pb bioavailability. The information provided in the review is fundamentally useful for the measurement of bioavailability and risk assessment practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Topographic variability influences the carbon sequestration potential of arable soils

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Elsgaard, Lars; Thomsen, Ingrid Kaag

    2012-01-01

    There is presently limited knowledge on the influence of field spatial variability on the carbon (C) sink-source relationships in arable landscapes. This is accompanied by the fact that our understanding of soil profile C dynamics is also limited. This study aimed at investigating how spatial...... results indicated that variability across arable landscapes makes footslope soils both a larger sink of buried soil C and a bigger potential CO2 source than upslope soils....

  13. Influence of amendments on soil structure and soil loss under ...

    African Journals Online (AJOL)

    Macromolecule polymers are significant types of chemical amendments because of their special structure, useful functions and low cost. Macromolecule polymers as soil amendment provide new territory for studying China's agricultural practices and for soil and water conservation, because polymers have the ability to ...

  14. Influence of Soil Properties on Soldierless Termite Distribution

    Czech Academy of Sciences Publication Activity Database

    Bourguignon, T.; Drouet, T.; Šobotník, J.; Hanus, Robert; Roisin, Y.

    2015-01-01

    Roč. 10, č. 8 (2015), e0135341/1-e0135341/11 E-ISSN 1932-6203 Institutional support: RVO:61388963 Keywords : tropical termites * soil -feeding termites * soil properties * soil preference Subject RIV: EH - Ecology, Behaviour Impact factor: 3.057, year: 2015 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0135341

  15. Factors Influencing Learner Permit Duration

    Directory of Open Access Journals (Sweden)

    Johnathon P. Ehsani

    2016-12-01

    Full Text Available An increasing number of countries are requiring an extended learner permit prior to independent driving. The question of when drivers begin the learner permit period, and how long they hold the permit before advancing to independent licensure has received little research attention. Licensure timing is likely to be related to “push” and “pull” factors which may encourage or inhibit the process. To examine this question, we recruited a sample of 90 novice drivers (49 females and 41 males, average age of 15.6 years soon after they obtained a learner permit and instrumented their vehicles to collect a range of driving data. Participants completed a series of surveys at recruitment related to factors that may influence licensure timing. Two distinct findings emerged from the time-to-event analysis that tested these push and pull factors in relation to licensure timing. The first can be conceptualized as teens’ motivation to drive (push, reflected in a younger age when obtaining a learner permit and extensive pre-permit driving experience. The second finding was teens’ perceptions of their parents’ knowledge of their activities (pull; a proxy for a parents’ attentiveness to their teens’ lives. Teens who reported higher levels of their parents’ knowledge of their activities took longer to advance to independent driving. These findings suggest time-to-licensure may be related to teens’ internal motivation to drive, and the ability of parents to facilitate or impede early licensure.

  16. Schistosomiasis, Soil-Transmitted Helminthiasis, and Sociodemographic Factors Influence Quality of Life of Adults in Côte d'Ivoire

    Science.gov (United States)

    Fürst, Thomas; Silué, Kigbafori D.; Ouattara, Mamadou; N'Goran, Dje N.; Adiossan, Lukas G.; N'Guessan, Yao; Zouzou, Fabian; Koné, Siaka; N'Goran, Eliézer K.; Utzinger, Jürg

    2012-01-01

    Background Burden of disease estimates are widely used for priority setting in public health and disability-adjusted life years are a powerful “currency” nowadays. However, disability weights, which capture the disability incurred by a typical patient of a certain condition, are fundamental to such burden calculation and their determination remains a widely debated issue. Methodology A cross-sectional epidemiological survey was conducted in the recently established Taabo health demographic surveillance system (HDSS) in south-central Côte d'Ivoire, to provide new, population-based evidence on the disability caused by schistosomiasis and soil-transmitted helminthiasis. Parasitological results from stool, urine, and blood examinations were juxtaposed to quality of life (QoL) questionnaire results from 187 adults. A multivariable linear regression model with stepwise backward elimination was used to identify significant associations, considering also sociodemographic characteristics obtained from the Taabo HDSS database. Principal Findings Prevalences for hookworm, Plasmodium spp., Trichuris trichiura, Schistosoma haematobium and Schistosoma mansoni were 39.0%, 18.2%, 2.7%, 2.1% and 2.1%, respectively. S. mansoni and T. trichiura infections of any intensity reduced the participants' self-rated QoL by 16 points (95% confidence interval (CI): 4–29 points) and 13 points (95% CI: 1–24 points), respectively, on a scale from 0 (worst QoL) to 100 points (best QoL). The only other statistically significant effect was a 1-point (95% CI: 0.1–2 points) increase on the QoL scale per one unit increase in a calculated wealth index. Conclusions/Significance We found consistent and significant results on the negative effects of schistosomiasis and soil-transmitted helminthiasis on adults' self-rated QoL, also when taking sociodemographic characteristics into account. Our results warrant further investigation on the disability incurred by helmintic infections and the

  17. Schistosomiasis, soil-transmitted helminthiasis, and sociodemographic factors influence quality of life of adults in Côte d'Ivoire.

    Science.gov (United States)

    Fürst, Thomas; Silué, Kigbafori D; Ouattara, Mamadou; N'Goran, Dje N; Adiossan, Lukas G; N'Guessan, Yao; Zouzou, Fabian; Koné, Siaka; N'Goran, Eliézer K; Utzinger, Jürg

    2012-01-01

    Burden of disease estimates are widely used for priority setting in public health and disability-adjusted life years are a powerful "currency" nowadays. However, disability weights, which capture the disability incurred by a typical patient of a certain condition, are fundamental to such burden calculation and their determination remains a widely debated issue. A cross-sectional epidemiological survey was conducted in the recently established Taabo health demographic surveillance system (HDSS) in south-central Côte d'Ivoire, to provide new, population-based evidence on the disability caused by schistosomiasis and soil-transmitted helminthiasis. Parasitological results from stool, urine, and blood examinations were juxtaposed to quality of life (QoL) questionnaire results from 187 adults. A multivariable linear regression model with stepwise backward elimination was used to identify significant associations, considering also sociodemographic characteristics obtained from the Taabo HDSS database. Prevalences for hookworm, Plasmodium spp., Trichuris trichiura, Schistosoma haematobium and Schistosoma mansoni were 39.0%, 18.2%, 2.7%, 2.1% and 2.1%, respectively. S. mansoni and T. trichiura infections of any intensity reduced the participants' self-rated QoL by 16 points (95% confidence interval (CI): 4-29 points) and 13 points (95% CI: 1-24 points), respectively, on a scale from 0 (worst QoL) to 100 points (best QoL). The only other statistically significant effect was a 1-point (95% CI: 0.1-2 points) increase on the QoL scale per one unit increase in a calculated wealth index. We found consistent and significant results on the negative effects of schistosomiasis and soil-transmitted helminthiasis on adults' self-rated QoL, also when taking sociodemographic characteristics into account. Our results warrant further investigation on the disability incurred by helmintic infections and the usefulness of generic QoL questionnaires in this endeavor.

  18. Factors influencing knowledge and practice of exclusive ...

    African Journals Online (AJOL)

    Factors influencing knowledge and practice of exclusive breastfeeding in Nyando ... The overall objective of this study was to determine factors influencing the ... EBF and its benefits), pre lacteal feeds and exclusive breastfeeding consistency.

  19. Influence of organic components on plutonium and americium speciation in soils and soil solutions

    International Nuclear Information System (INIS)

    Sokolik, G.A.; Ovsyannikova, S.V.; Kimlenko, I.M.

    2003-01-01

    Group composition of humic substances of organic and mineral soils sampled in the 30-km zone of the Chernobyl accident was analyzed for studying influence of organic components on migration properties of plutonium and americium in soils and soil solutions by the method of gel-chromatography and chemical fractionation. It was ascertained that humus of organic soils binds plutonium and americium stronger than humus of mineral soils. Elevated mobility of americium compared to plutonium one stems from lower ability of the latter to from hard to solve organic and organomineral complexes, as well as from its ability to form anionic complexes in soil solutions [ru

  20. Plant and bird presence strongly influences the microbial communities in soils of Admiralty Bay, Maritime Antarctica.

    Science.gov (United States)

    Teixeira, Lia C R S; Yeargeau, Etienne; Balieiro, Fabiano C; Piccolo, Marisa C; Peixoto, Raquel S; Greer, Charles W; Rosado, Alexandre S

    2013-01-01

    Understanding the environmental factors that shape microbial communities is crucial, especially in extreme environments, like Antarctica. Two main forces were reported to influence Antarctic soil microbes: birds and plants. Both birds and plants are currently undergoing relatively large changes in their distribution and abundance due to global warming. However, we need to clearly understand the relationship between plants, birds and soil microorganisms. We therefore collected rhizosphere and bulk soils from six different sampling sites subjected to different levels of bird influence and colonized by Colobanthus quitensis and Deschampsia antarctica in Admiralty Bay, King George Island, Maritime Antarctic. Microarray and qPCR assays targeting 16S rRNA genes of specific taxa were used to assess microbial community structure, composition and abundance and analyzed with a range of soil physico-chemical parameters. The results indicated significant rhizosphere effects in four out of the six sites, including areas with different levels of bird influence. Acidobacteria were significantly more abundant in soils with little bird influence (low nitrogen) and in bulk soil. In contrast, Actinobacteria were significantly more abundant in the rhizosphere of both plant species. At two of the sampling sites under strong bird influence (penguin colonies), Firmicutes were significantly more abundant in D. antarctica rhizosphere but not in C. quitensis rhizosphere. The Firmicutes were also positively and significantly correlated to the nitrogen concentrations in the soil. We conclude that the microbial communities in Antarctic soils are driven both by bird and plants, and that the effect is taxa-specific.

  1. Plant and bird presence strongly influences the microbial communities in soils of Admiralty Bay, Maritime Antarctica.

    Directory of Open Access Journals (Sweden)

    Lia C R S Teixeira

    Full Text Available Understanding the environmental factors that shape microbial communities is crucial, especially in extreme environments, like Antarctica. Two main forces were reported to influence Antarctic soil microbes: birds and plants. Both birds and plants are currently undergoing relatively large changes in their distribution and abundance due to global warming. However, we need to clearly understand the relationship between plants, birds and soil microorganisms. We therefore collected rhizosphere and bulk soils from six different sampling sites subjected to different levels of bird influence and colonized by Colobanthus quitensis and Deschampsia antarctica in Admiralty Bay, King George Island, Maritime Antarctic. Microarray and qPCR assays targeting 16S rRNA genes of specific taxa were used to assess microbial community structure, composition and abundance and analyzed with a range of soil physico-chemical parameters. The results indicated significant rhizosphere effects in four out of the six sites, including areas with different levels of bird influence. Acidobacteria were significantly more abundant in soils with little bird influence (low nitrogen and in bulk soil. In contrast, Actinobacteria were significantly more abundant in the rhizosphere of both plant species. At two of the sampling sites under strong bird influence (penguin colonies, Firmicutes were significantly more abundant in D. antarctica rhizosphere but not in C. quitensis rhizosphere. The Firmicutes were also positively and significantly correlated to the nitrogen concentrations in the soil. We conclude that the microbial communities in Antarctic soils are driven both by bird and plants, and that the effect is taxa-specific.

  2. Plant and Bird Presence Strongly Influences the Microbial Communities in Soils of Admiralty Bay, Maritime Antarctica

    Science.gov (United States)

    Teixeira, Lia C. R. S.; Yeargeau, Etienne; Balieiro, Fabiano C.; Piccolo, Marisa C.; Peixoto, Raquel S.; Greer, Charles W.; Rosado, Alexandre S.

    2013-01-01

    Understanding the environmental factors that shape microbial communities is crucial, especially in extreme environments, like Antarctica. Two main forces were reported to influence Antarctic soil microbes: birds and plants. Both birds and plants are currently undergoing relatively large changes in their distribution and abundance due to global warming. However, we need to clearly understand the relationship between plants, birds and soil microorganisms. We therefore collected rhizosphere and bulk soils from six different sampling sites subjected to different levels of bird influence and colonized by Colobanthus quitensis and Deschampsia antarctica in Admiralty Bay, King George Island, Maritime Antarctic. Microarray and qPCR assays targeting 16S rRNA genes of specific taxa were used to assess microbial community structure, composition and abundance and analyzed with a range of soil physico-chemical parameters. The results indicated significant rhizosphere effects in four out of the six sites, including areas with different levels of bird influence. Acidobacteria were significantly more abundant in soils with little bird influence (low nitrogen) and in bulk soil. In contrast, Actinobacteria were significantly more abundant in the rhizosphere of both plant species. At two of the sampling sites under strong bird influence (penguin colonies), Firmicutes were significantly more abundant in D. antarctica rhizosphere but not in C. quitensis rhizosphere. The Firmicutes were also positively and significantly correlated to the nitrogen concentrations in the soil. We conclude that the microbial communities in Antarctic soils are driven both by bird and plants, and that the effect is taxa-specific. PMID:23840411

  3. [Interrelationships between soil fauna and soil environmental factors in China: research advance].

    Science.gov (United States)

    Wang, Yi; Wei, Wei; Yang, Xing-zhong; Chen, Li-ding; Yang, Lei

    2010-09-01

    Soil fauna has close relations with various environmental factors in soil ecosystem. To explore the interrelationships between soil fauna and soil environmental factors is of vital importance to deep understand the dynamics of soil ecosystem and to assess the functioning of the ecosystem. The environmental factors affecting soil fauna can be classified as soil properties and soil external environment. The former contains soil basic physical and chemical properties, soil moisture, and soil pollution. The latter includes vegetation, land use type, landform, and climate, etc. From these aspects, this paper summarized the published literatures in China on the interrelationships between soil fauna and soil environmental factors. It was considered that several problems were existed in related studies, e.g., fewer researches were made in integrating soil fauna's bio-indicator function, research methods were needed to be improved, and the studies on the multi-environmental factors and their large scale spatial-temporal variability were in deficiency. Corresponding suggestions were proposed, i.e., more work should be done according to the practical needs, advanced experiences from abroad should be referenced, and comprehensive studies on multi-environmental factors and long-term monitoring should be conducted on large scale areas.

  4. The influence of vertical sorbed phase transport on the fate of organic chemicals in surface soils.

    Science.gov (United States)

    McLachlan, Michael S; Czub, Gertje; Wania, Frank

    2002-11-15

    Gaseous exchange between surface soil and the atmosphere is an important process in the environmental fate of many chemicals. It was hypothesized that this process is influenced by vertical transport of chemicals sorbed to soil particles. Vertical sorbed phase transport in surface soils occurs by many processes such as bioturbation, cryoturbation, and erosion into cracks formed by soil drying. The solution of the advection/diffusion equation proposed by Jury et al. to describe organic chemical fate in a uniformly contaminated surface soil was modified to include vertical sorbed phase transport This process was modeled using a sorbed phase diffusion coefficient, the value of which was derived from soil carbon mass balances in the literature. The effective diffusivity of the chemical in a typical soil was greater in the modified model than in the model without sorbed phase transport for compounds with log K(OW) > 2 and log K(OA) > 6. Within this chemical partitioning space, the rate of volatilization from the surface soil was larger in the modified model than in the original model by up to a factor of 65. The volatilization rate was insensitive to the value of the sorbed phase diffusion coefficient throughout much of this chemical partitioning space, indicating that the surface soil layer was essentially well-mixed and that the mass transfer coefficient was determined by diffusion through the atmospheric boundary layer only. When this process was included in a non-steady-state regional multimedia chemical fate model running with a generic emissions scenario to air, the predicted soil concentrations increased by upto a factor of 25,whilethe air concentrations decreased by as much as a factor of approximately 3. Vertical sorbed phase transport in the soil thus has a major impact on predicted air and soil concentrations, the state of equilibrium, and the direction and magnitude of the chemical flux between air and soil. It is a key process influencing the environmental

  5. Soil types and limiting factors in agricultural production in the San Fernando district, Tamaulipas, Mexico

    International Nuclear Information System (INIS)

    Espinosa Ramirez, M.; Garza Cedillo, R.; Andrade limas, E.; Belmonte Serrato, F.

    2009-01-01

    The limiting factors in agricultural production, defined as those properties and characteristics of the geographical environment that influence the development of crops, can be diverse and are grouped with the physical environment of soil. They are the result of soil characteristics and soil degradation processes by anthropogenic influence. Due to the above, the objective of this study was to identify and surveying the limitative factors to agricultural production, as well as to define its ability land use capacity in San Fernando district, Tamaulipas. (Author) 7 refs.

  6. Influence of facing vertical stiffness on reinforced soil wall design

    OpenAIRE

    Puig Damians, Ivan; Bathurst, Richard; Josa Garcia-Tornel, Alejandro; Lloret Morancho, Antonio

    2013-01-01

    Current design practices for reinforced soil walls typically ignore the influence of facing type and foundation compressibility on the magnitude and distribution of reinforcement loads in steel reinforced soil walls under operational conditions. In this paper, the effect of the facing vertical stiffness (due to elastomeric bearing pads placed in the horizontal joints between panels) on load capacity of steel reinforced soil walls is examined in a systematic manner using a numerical modelli...

  7. Study on Erosion Factors Affecting Kuroboku Soil Loss I. Water Permeability of Stratified Soil and Slope Gradient

    OpenAIRE

    田熊, 勝利; 猪迫, 耕二; 中原 恒,

    2005-01-01

    The authors examined the factors of bed soil affecting the loss of surface soil and the effects of these factors on the extent of the soil loss. They conducted a multivariate analysis using actual measurement value at a laboratory erosion experiment. They also conducted a simulation of erosion in soil loss using the bed soil factors. Soil loss quantity is dependent on the coefficient of permeability of bed soil; the steeper the latter is, the more the former increases. Lateral soil scattering...

  8. Influence of fuelwood trees on sodic soils

    International Nuclear Information System (INIS)

    Garg, V.K.; Jain, R.K.

    1992-01-01

    The persistent acute fuelwood shortage problem in India has necessitated having tree plantations on waste lands to obtain renewable energy. Fuelwood production screening trials initiated in 1981 at the Biomass Research Centre in Banthra, India identified babul, Acacia nilotica (L.) Wild. ex Delile, and mesquite, Prosopis juliflora (Swartz) DC., to be the most promising and suitable leguminous trees in terms of biomass production on sodic sites. A study was carried out to assess soil enrichment due to the growth of these fuelwood trees planted a decade past on sordic soil that had had no other amendments. Results showed preferential nutrient accumulation and greater reduction in soil pH (from 9.5 to 7.9) and exchangeable sodium (from 30 to 8%) at the P. juliflora plantation compared with at the A. nilotica plantation. There was also a reduction in surface soil (0-15 cm) bulk density, but an enhancement in porosity and water holding capacity, making soil more friable. The P. juliflora plantation produced markedly more leaf litter than the A. nilotica plantation. Both the species had fibrous lateral root systems on the surface in the sodic soil. However, the penetration and spread of roots were almost 2-fold greater in P. juliflora than in A. nilotica. Thus, the potential magnitude of changes in soil properties was related to the distribution of roots and amount of litter falling on the soil surface. Prosopis juliflora appeared to be better than A. nilotica under adverse sodic soil conditions in establishing an enlarged plant-litter nutrient cycle relationship. This study also provides an assessment of soil amelioration by leguminous trees under short-rotation forestry practices. 16 refs., 7 figs., 4 tabs

  9. Influence of fuelwood trees on sodic soils

    Energy Technology Data Exchange (ETDEWEB)

    Garg, V.K.; Jain, R.K. (National Botanical Research Inst., Lucknow (India))

    1992-01-01

    The persistent acute fuelwood shortage problem in India has necessitated having tree plantations on waste lands to obtain renewable energy. Fuelwood production screening trials initiated in 1981 at the Biomass Research Centre in Banthra, India identified babul, Acacia nilotica (L.) Wild. ex Delile, and mesquite, Prosopis juliflora (Swartz) DC., to be the most promising and suitable leguminous trees in terms of biomass production on sodic sites. A study was carried out to assess soil enrichment due to the growth of these fuelwood trees planted a decade past on sordic soil that had had no other amendments. Results showed preferential nutrient accumulation and greater reduction in soil pH (from 9.5 to 7.9) and exchangeable sodium (from 30 to 8%) at the P. juliflora plantation compared with at the A. nilotica plantation. There was also a reduction in surface soil (0-15 cm) bulk density, but an enhancement in porosity and water holding capacity, making soil more friable. The P. juliflora plantation produced markedly more leaf litter than the A. nilotica plantation. Both the species had fibrous lateral root systems on the surface in the sodic soil. However, the penetration and spread of roots were almost 2-fold greater in P. juliflora than in A. nilotica. Thus, the potential magnitude of changes in soil properties was related to the distribution of roots and amount of litter falling on the soil surface. Prosopis juliflora appeared to be better than A. nilotica under adverse sodic soil conditions in establishing an enlarged plant-litter nutrient cycle relationship. This study also provides an assessment of soil amelioration by leguminous trees under short-rotation forestry practices. 16 refs., 7 figs., 4 tabs.

  10. Physiological factors influencing capillary growth.

    Science.gov (United States)

    Egginton, S

    2011-07-01

    (1) Angiogenesis (growth of new capillaries from an existing capillary bed) may result from a mismatch in microvascular supply and metabolic demand (metabolic error signal). Krogh examined the distribution and number of capillaries to explore the correlation between O(2) delivery and O(2) consumption. Subsequently, the heterogeneity in angiogenic response within a muscle has been shown to reflect either differences in fibre type composition or mechanical load. However, local control leads to targetted angiogenesis in the vicinity of glycolytic fibre types following muscle stimulation, or oxidative fibres following endurance training, while heterogeneity of capillary spacing is maintained during ontogenetic growth. (2) Despite limited microscopy resolution and lack of specific markers, Krogh's interest in the structure of the capillary wall paved the way for understanding the mechanisms of capillary growth. Angiogenesis may be influenced by the response of perivascular or stromal cells (fibroblasts, macrophages and pericytes) to altered activity, likely acting as a source for chemical signals modulating capillary growth such as vascular endothelial growth factor. In addition, haemodynamic factors such as shear stress and muscle stretch play a significant role in adaptive remodelling of the microcirculation. (3) Most indices of capillarity are highly dependent on fibre size, resulting in possible bias because of scaling. To examine the consequences of capillary distribution, it is therefore helpful to quantify the area of tissue supplied by individual capillaries. This allows the spatial limitations inherent in most models of tissue oxygenation to be overcome generating an alternative approach to Krogh's tissue cylinder, the capillary domain, to improve descriptions of intracellular oxygen diffusion. © 2010 The Author. Acta Physiologica © 2010 Scandinavian Physiological Society.

  11. Factors Influencing HEPA Filter Performance

    International Nuclear Information System (INIS)

    Parsons, M.S.; Waggoner, Ch.A.

    2009-01-01

    Properly functioning HEPA air filtration systems depend on a variety of factors that start with the use of fully characterized challenge conditions for system design and then process control during operation. This paper addresses factors that should be considered during the design phase as well as operating parameters that can be monitored to ensure filter function and lifetime. HEPA filters used in nuclear applications are expected to meet design, fabrication, and performance requirements set forth in the ASME AG-1 standard. The DOE publication Nuclear Air Cleaning Handbook (NACH) is an additional guidance document for design and operation HEPA filter systems in DOE facilities. These two guidelines establish basic maximum operating parameters for temperature, maximum aerosol particle size, maximum particulate matter mass concentration, acceptable differential pressure range, and filter media velocity. Each of these parameters is discussed along with data linking variability of each parameter with filter function and lifetime. Temporal uncertainty associated with gas composition, temperature, and absolute pressure of the air flow can have a direct impact on the volumetric flow rate of the system with a corresponding impact on filter media velocity. Correlations between standard units of flow rate (standard meters per minute or cubic feet per minute) versus actual units of volumetric flow rate are shown for variations in relative humidity for a 70 deg. C to 200 deg. C temperature range as an example of gas composition that, uncorrected, will influence media velocity. The AG-1 standard establishes a 2.5 cm/s (5 feet per minute) ceiling for media velocities of nuclear grade HEPA filters. Data are presented that show the impact of media velocities from 2.0 to 4.0 cm/s media velocities (4 to 8 fpm) on differential pressure, filter efficiency, and filter lifetime. Data will also be presented correlating media velocity effects with two different particle size

  12. Impact of environmental factors and biological soil crust types on soil respiration in a desert ecosystem.

    Science.gov (United States)

    Feng, Wei; Zhang, Yuqing; Jia, Xin; Wu, Bin; Zha, Tianshan; Qin, Shugao; Wang, Ben; Shao, Chenxi; Liu, Jiabin; Fa, Keyu

    2014-01-01

    The responses of soil respiration to environmental conditions have been studied extensively in various ecosystems. However, little is known about the impacts of temperature and moisture on soils respiration under biological soil crusts. In this study, CO2 efflux from biologically-crusted soils was measured continuously with an automated chamber system in Ningxia, northwest China, from June to October 2012. The highest soil respiration was observed in lichen-crusted soil (0.93 ± 0.43 µmol m-2 s-1) and the lowest values in algae-crusted soil (0.73 ± 0.31 µmol m-2 s-1). Over the diurnal scale, soil respiration was highest in the morning whereas soil temperature was highest in the midday, which resulted in diurnal hysteresis between the two variables. In addition, the lag time between soil respiration and soil temperature was negatively correlated with the soil volumetric water content and was reduced as soil water content increased. Over the seasonal scale, daily mean nighttime soil respiration was positively correlated with soil temperature when moisture exceeded 0.075 and 0.085 m3 m-3 in lichen- and moss-crusted soil, respectively. However, moisture did not affect on soil respiration in algae-crusted soil during the study period. Daily mean nighttime soil respiration normalized by soil temperature increased with water content in lichen- and moss-crusted soil. Our results indicated that different types of biological soil crusts could affect response of soil respiration to environmental factors. There is a need to consider the spatial distribution of different types of biological soil crusts and their relative contributions to the total C budgets at the ecosystem or landscape level.

  13. Impact of Environmental Factors and Biological Soil Crust Types on Soil Respiration in a Desert Ecosystem

    Science.gov (United States)

    Feng, Wei; Zhang, Yuqing; Jia, Xin; Wu, Bin; Zha, Tianshan; Qin, Shugao; Wang, Ben; Shao, Chenxi; Liu, Jiabin; Fa, Keyu

    2014-01-01

    The responses of soil respiration to environmental conditions have been studied extensively in various ecosystems. However, little is known about the impacts of temperature and moisture on soils respiration under biological soil crusts. In this study, CO2 efflux from biologically-crusted soils was measured continuously with an automated chamber system in Ningxia, northwest China, from June to October 2012. The highest soil respiration was observed in lichen-crusted soil (0.93±0.43 µmol m−2 s−1) and the lowest values in algae-crusted soil (0.73±0.31 µmol m−2 s−1). Over the diurnal scale, soil respiration was highest in the morning whereas soil temperature was highest in the midday, which resulted in diurnal hysteresis between the two variables. In addition, the lag time between soil respiration and soil temperature was negatively correlated with the soil volumetric water content and was reduced as soil water content increased. Over the seasonal scale, daily mean nighttime soil respiration was positively correlated with soil temperature when moisture exceeded 0.075 and 0.085 m3 m−3 in lichen- and moss-crusted soil, respectively. However, moisture did not affect on soil respiration in algae-crusted soil during the study period. Daily mean nighttime soil respiration normalized by soil temperature increased with water content in lichen- and moss-crusted soil. Our results indicated that different types of biological soil crusts could affect response of soil respiration to environmental factors. There is a need to consider the spatial distribution of different types of biological soil crusts and their relative contributions to the total C budgets at the ecosystem or landscape level. PMID:25050837

  14. Factors impacting the electro conductivity variations of clayey soils

    International Nuclear Information System (INIS)

    Ouhadi, V. R.; Goodarzi, A. R.

    2007-01-01

    The variation of pore fluid properties in soil has a major effect on soil behaviour. This effect is a function of pore fluid properties and soil mineralogy. Such variation usually happens in the reservoirs of dams or in some geotechnical projects. The electro conductivity measurement is a simple method to monitor any variation in the pore fluid of soils. electro conductivity is the ability of a material to transmit (conduct) an electrical current. This paper focuses attention on the effect of soil-pore fluid interaction on the electro conductivity of clayey soils. A set of physico-chemical experiments are performed and the role of different factors including soil pH, soil mineralogy, soil: water ratio, cation and anion effects are investigated. The results of this study indicate that for soil that has a relatively low CEC, the anion type is an important factor, while the cation type does not noticeably affect the electro conductivity of the soil-solution. However, for such soil, an electrolyte property, i.e. its solubility, is much more effective than the CEC of the soil. In addition, it was observed that in the presence of neutral salts such as pore fluid, the pH of the soil-solution decreases causing an increase in the electro conductivity of the soil sample

  15. Influence of Soil Solution Salinity on Molybdenum Adsorption by Soils

    Science.gov (United States)

    Molybdenum (Mo) adsorption on five arid-zone soils from California was investigated as a function of equilibrium solution Mo concentration (0-30 mg L-1), solution pH (4-8), and electrical conductivity (EC = 0.3 or 8 dS m-1). Molybdenum adsorption decreased with increasing pH. An adsorption maximum...

  16. Influence of lokpa cattle market wastes on agricultural soil quality ...

    African Journals Online (AJOL)

    Influence of lokpa cattle market wastes on agricultural soil quality. ... African Journal of Environmental Science and Technology ... Soil samples were collected from the Central, 3 and 6 m Northwards, Southwards, Eastwards and Westwards of Lokpa cattle market, Umuneochi Local Government Area of Abia State, Nigeria at ...

  17. FACTORS INFLUENCING THE EVOLUTION OF YOUTH TRAVEL

    Directory of Open Access Journals (Sweden)

    Student Claudia MOISĂ

    2010-01-01

    Full Text Available Youth travel is an important part of global tourism, consequently, getting to know the evolution of this form of tourism requires an approach of the aspects regarding the permissive and restrictive factors that influence the youth travel dynamic worldwide. In terms of the factors that influence youth travel, we highlighted these two categories of factors (permissive and restrictive and, within each category, we tried to singularize the influence of every factor over youth travel.

  18. Environmental and management influences on temporal variability of near saturated soil hydraulic properties.

    Science.gov (United States)

    Bodner, G; Scholl, P; Loiskandl, W; Kaul, H-P

    2013-08-01

    Structural porosity is a decisive property for soil productivity and soil environmental functions. Hydraulic properties in the structural range vary over time in response to management and environmental influences. Although this is widely recognized, there are few field studies that determine dominant driving forces underlying hydraulic property dynamics. During a three year field experiment we measured temporal variability of soil hydraulic properties by tension infiltrometry. Soil properties were characterized by hydraulic conductivity, effective macroporosity and Kosugi's lognormal pore size distribution model. Management related influences comprised three soil cover treatment (mustard and rye vs. fallow) and an initial mechanical soil disturbance with a rotary harrow. Environmental driving forces were derived from meteorological and soil moisture data. Soil hydraulic parameters varied over time by around one order of magnitude. The coefficient of variation of soil hydraulic conductivity K(h) decreased from 69.5% at saturation to 42.1% in the more unsaturated range (- 10 cm pressure head). A slight increase in the Kosugi parameter showing pore heterogeneity was observed under the rye cover crop, reflecting an enhanced structural porosity. The other hydraulic parameters were not significantly influenced by the soil cover treatments. Seedbed preparation with a rotary harrow resulted in a fourfold increase in macroporosity and hydraulic conductivity next to saturation, and homogenized the pore radius distribution. Re-consolidation after mechanical loosening lasted over 18 months until the soil returned to its initial state. The post-tillage trend of soil settlement could be approximated by an exponential decay function. Among environmental factors, wetting-drying cycles were identified as dominant driving force explaining short term hydraulic property changes within the season (r 2  = 0.43 to 0.59). Our results suggested that beside considering average

  19. Influence of physical and chemical properties of different soil types on optimal soil moisture for tillage

    Directory of Open Access Journals (Sweden)

    Vladimir Zebec

    2017-01-01

    Full Text Available Soil plasticity is the area of soil consistency, i.e. it represents a change in soil condition due to different soil moisture influenced by external forces activity. Consistency determines soil resistance in tillage, therefore, the aim of the research was to determine the optimum soil moisture condition for tillage and the influence of the chemical and physical properties of the arable land horizons on the soil plasticity on three different types of soil (fluvisol, luvisol and humic glaysol. Statistically significant differences were found between all examined soil types, such as the content of clay particles, the density of packaging and the actual and substitution acidity, the cation exchange capacity and the content of calcium. There were also statistically significant differences between the examined types of soil for the plasticity limit, liquid limit and the plasticity index. The average established value of plasticity limit as an important element for determining the optimal moment of soil tillage was 18.9% mass on fluvisol, 24.0% mass on luvisol and 28.6% mass on humic glaysol. Very significant positive direction correlation with plasticity limits was shown by organic matter, clay, fine silt, magnesium, sodium and calcium, while very significant negative direction correlation was shown by hydrolytic acidity, coarse sand, fine sand and coarse silt. Created regression models can estimate the optimal soil moisture condition for soil cultivation based on the basic soil properties. The model precision is significantly increased by introducing a greater number of agrochemical and agrophysical soil properties, and the additional precision of the model can be increased by soil type data.

  20. Influence of Terraced area DEM Resolution on RUSLE LS Factor

    Science.gov (United States)

    Zhang, Hongming; Baartman, Jantiene E. M.; Yang, Xiaomei; Gai, Lingtong; Geissen, Viollette

    2017-04-01

    Topography has a large impact on the erosion of soil by water. Slope steepness and slope length are combined (the LS factor) in the universal soil-loss equation (USLE) and its revised version (RUSLE) for predicting soil erosion. The LS factor is usually extracted from a digital elevation model (DEM). The grid size of the DEM will thus influence the LS factor and the subsequent calculation of soil loss. Terracing is considered as a support practice factor (P) in the USLE/RUSLE equations, which is multiplied with the other USLE/RUSLE factors. However, as terraces change the slope length and steepness, they also affect the LS factor. The effect of DEM grid size on the LS factor has not been investigated for a terraced area. We obtained a high-resolution DEM by unmanned aerial vehicles (UAVs) photogrammetry, from which the slope steepness, slope length, and LS factor were extracted. The changes in these parameters at various DEM resolutions were then analysed. The DEM produced detailed LS-factor maps, particularly for low LS factors. High (small valleys, gullies, and terrace ridges) and low (flats and terrace fields) spatial frequencies were both sensitive to changes in resolution, so the areas of higher and lower slope steepness both decreased with increasing grid size. Average slope steepness decreased and average slope length increased with grid size. Slope length, however, had a larger effect than slope steepness on the LS factor as the grid size varied. The LS factor increased when the grid size increased from 0.5 to 30-m and increased significantly at grid sizes >5-m. The LS factor was increasingly overestimated as grid size decreased. The LS factor decreased from grid sizes of 30 to 100-m, because the details of the terraced terrain were gradually lost, but the factor was still overestimated.

  1. Factors influencing boar sperm cryosurvival.

    Science.gov (United States)

    Roca, J; Hernández, M; Carvajal, G; Vázquez, J M; Martínez, E A

    2006-10-01

    Optimal sperm cryopreservation is a prerequisite for the sustainable commercial application of frozen-thawed boar semen for AI. Three experiments were performed to identify factors influencing variability of postthaw sperm survival among 464 boar ejaculates. Sperm-rich ejaculate fractions were cryopre-served using a standard freezing-thawing procedure for 0.5-mL plastic straws and computer-controlled freezing equipment. Postthaw sperm motility (assessed with a computer-assisted semen analysis system) and viability (simultaneously probed by flow cytometry analysis after triple-fluorescent stain), evaluated 30 and 150 min postthaw, were used to estimate the success of cryopreservation. In the first experiment, 168 unselected ejaculates (1 ejaculate/boar), from boars of 6 breeds with a wide age range (8 to 48 mo), were cryopreserved over a 12-mo period to evaluate the predictive value of boar (breed and age), semen collection, transport variables (season of ejaculate collection, interval between collections, and ejaculate temperature exposure), initial semen traits, and sperm quality before freezing on sperm survival after freezing-thawing. In Exp. 2, 4 ejaculates from each of 29 boars, preselected according to their initial semen traits and sperm quality before freezing, were collected and frozen over a 6-mo period to evaluate the influence of interboar and intraboar ejaculate variability in the survival of sperm after cryopreservation. In Exp. 3, 12 ejaculates preselected as for Exp. 2, from each of 15 boars with known good sperm cryosurvival, were collected and frozen over a 12-mo period to estimate the sustainability of sperm cryosurvival between ejaculates over time. Boar and semen collection and transport variables were not predictive of sperm cryosurvival among ejaculates. Initial semen traits and sperm quality variables observed before freezing explained 23.2 and 10.9%, respectively, of the variation in postthaw sperm motility and viability. However, more that

  2. Influence of soil structure on the "Fv approach" applied to 238U and 226Ra.

    Science.gov (United States)

    Blanco Rodríguez, P; Vera Tomé, F; Lozano, J C

    2017-02-01

    The soil-to-plant transfer factors were determined in a granitic area for the two long-lived uranium series radionuclides 238 U and 226 Ra. With the aim to identify a physical fraction of soil whose concentration correlates linearly with the plant concentration, the soil compartment was analyzed in various stages. An initial study identified the soil compartments as being either bulk soil or its labile fraction. The bulk soil was subsequently divided into three granulometric fractions consisting of: coarse sand, fine sand, and silt and clay. The soil-to-plant transfer of radionuclides for each of these three texture fractions was analyzed. Lastly, the labile fraction was extracted from each textural part, and the activity concentration of the radionuclides 238 U and 226 Ra was measured. In order to assess the influence of soil texture on the soil-to-plant transfer process, we sought to identify possible correlations between the activity concentration in the plant compartment and those found in the different fractions within each soil compartment. The results showed that the soil-to-plant transfer process for uranium and radium depends on soil grain size, where the results for uranium showed a linear relationship between the activity concentration of uranium in the plant and the fine soil fraction. In contrast, a linear relation between the activity concentration of radium in the plant and the soil coarse-sand fraction was observed. Additionally, the presence of phosphate and calcium in the soil of all of the compartments studied affected the soil-to-plant transfer of uranium and radium, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Soil-plant-transfer factors for I-129 and pasture vegetation

    International Nuclear Information System (INIS)

    Haisch, A.; Schuettelkopf, H.

    1993-07-01

    The transfer factors for soil/plant, I-129 and I-127 and pasture vegetation have been measured with soils developed by wethering of granite, jura and cretaceous formations. Greenhouse (Karlsruhe) and field experiments (Munich) have been performed using lysimeters. Three ground water levels and the influence of a six weeks flooding was measured. About 90% of the transfer factors ranged from 0.000 to 0.020. The highest values have been determined with soils from granite wethering. The flooding of the lysimeters caused an important increase of the transfer factors after the end of flooding. (orig.) [de

  4. A New European Slope Length and Steepness Factor (LS-Factor for Modeling Soil Erosion by Water

    Directory of Open Access Journals (Sweden)

    Panos Panagos

    2015-04-01

    Full Text Available The Universal Soil Loss Equation (USLE model is the most frequently used model for soil erosion risk estimation. Among the six input layers, the combined slope length and slope angle (LS-factor has the greatest influence on soil loss at the European scale. The S-factor measures the effect of slope steepness, and the L-factor defines the impact of slope length. The combined LS-factor describes the effect of topography on soil erosion. The European Soil Data Centre (ESDAC developed a new pan-European high-resolution soil erosion assessment to achieve a better understanding of the spatial and temporal patterns of soil erosion in Europe. The LS-calculation was performed using the original equation proposed by Desmet and Govers (1996 and implemented using the System for Automated Geoscientific Analyses (SAGA, which incorporates a multiple flow algorithm and contributes to a precise estimation of flow accumulation. The LS-factor dataset was calculated using a high-resolution (25 m Digital Elevation Model (DEM for the whole European Union, resulting in an improved delineation of areas at risk of soil erosion as compared to lower-resolution datasets. This combined approach of using GIS software tools with high-resolution DEMs has been successfully applied in regional assessments in the past, and is now being applied for first time at the European scale.

  5. Modification of the USLE K factor for soil erodibility assessment on calcareous soils in Iran

    Science.gov (United States)

    Ostovari, Yaser; Ghorbani-Dashtaki, Shoja; Bahrami, Hossein-Ali; Naderi, Mehdi; Dematte, Jose Alexandre M.; Kerry, Ruth

    2016-11-01

    The measurement of soil erodibility (K) in the field is tedious, time-consuming and expensive; therefore, its prediction through pedotransfer functions (PTFs) could be far less costly and time-consuming. The aim of this study was to develop new PTFs to estimate the K factor using multiple linear regression, Mamdani fuzzy inference systems, and artificial neural networks. For this purpose, K was measured in 40 erosion plots with natural rainfall. Various soil properties including the soil particle size distribution, calcium carbonate equivalent, organic matter, permeability, and wet-aggregate stability were measured. The results showed that the mean measured K was 0.014 t h MJ- 1 mm- 1 and 2.08 times less than the estimated mean K (0.030 t h MJ- 1 mm- 1) using the USLE model. Permeability, wet-aggregate stability, very fine sand, and calcium carbonate were selected as independent variables by forward stepwise regression in order to assess the ability of multiple linear regression, Mamdani fuzzy inference systems and artificial neural networks to predict K. The calcium carbonate equivalent, which is not accounted for in the USLE model, had a significant impact on K in multiple linear regression due to its strong influence on the stability of aggregates and soil permeability. Statistical indices in validation and calibration datasets determined that the artificial neural networks method with the highest R2, lowest RMSE, and lowest ME was the best model for estimating the K factor. A strong correlation (R2 = 0.81, n = 40, p soils.

  6. Factors that negatively influence consumption of traditionally ...

    African Journals Online (AJOL)

    Factors that negatively influence consumption of traditionally fermented milk ... in various countries of sub-Saharan Africa and a number of health benefits to human ... influence consumption of Mursik, a traditionally fermented milk product from ...

  7. Different influences of field aging on nickel toxicity to Folsomia candida in two types of soil.

    Science.gov (United States)

    Liu, Yu-Rong; Li, Jing; He, Ji-Zheng; Ma, Yi-Bing; Zheng, Yuan-Ming

    2015-06-01

    Metal aging in soils has been considered an important factor influencing its availability and toxicity to organisms. In this study, we report the influence of 5 years field aging on the nickel (Ni) toxicity to collembolan Folsomia candida based on two different types of soil from Dezhou (DZ) and Qiyang (QY) counties in China. Acute and chronic toxicity of Ni to F. candida was assessed in both freshly spiked and field aging contaminated soils. We found that 5 years field aging increased the EC50 and 2d-LC50 values of Ni to F. candida in the DZ soil, while little influence on the Ni toxicity was observed in the QY soil. There was no adverse effect of the long-term field aging on the Ni toxicity to the survival of F. candida in the two tested soils. In addition, field aging of the two soils impacted differently the water-soluble Ni concentrations, which were significantly correlated to the juvenile production of F. candida based on a logistic model. Our study highlights different effects of long-term field aging on the Ni toxicity to F. candida between divergent types of soil, and this should be taken into account in future toxicity testing and risk assessment practices.

  8. Zinc fractionation in contaminated soils by sequential and single extractions: influence of soil properties and zinc content.

    Science.gov (United States)

    Voegelin, Andreas; Tokpa, Gerome; Jacquat, Olivier; Barmettler, Kurt; Kretzschmar, Ruben

    2008-01-01

    We studied the fractionation of zinc (Zn) in 49 contaminated soils as influenced by Zn content and soil properties using a seven-step sequential extraction procedure (F1: NH4NO3; F2: NH4-acetate, pH 6; F3: NH3OHCl, pH 6; F4: NH4-EDTA, pH 4.6; F5: NH4-oxalate, pH 3; F6: NH4-oxalate/ascorbic acid, pH 3; F7: residual). The soils had developed from different geologic materials and covered a wide range in soil pH (4.0-7.3), organic C content (9.3-102 g kg(-1)), and clay content (38-451 g kg(-1)). Input of aqueous Zn with runoff water from electricity towers during 26 to 74 yr resulted in total soil Zn contents of 3.8 to 460 mmol kg(-1). In acidic soils (n = 24; pH soils (n = 25; pH > or =6.0), most Zn was extracted in the mobilizable fraction (F2) and the intermediate fractions (F4 and F5). The extractability of Zn increased with increasing Zn contamination of the soils. The sum of mobile (F1) and mobilizable (F2) Zn was independent of soil pH, the ratio of Zn in F1 over F1+F2 plotted against soil pH, exhibited the typical shape of a pH sorption edge and markedly increased from pH 6 to pH 5, reflecting the increasing lability of mobilizable Zn with decreasing soil pH. In conclusion, the extractability of Zn from soils contaminated with aqueous Zn after decades of aging under field conditions systematically varied with soil pH and Zn content. The same trends are expected to apply to aqueous Zn released from decomposing Zn-bearing contaminants, such as sewage sludge or smelter slag. The systematic trends in Zn fractionation with varying soil pH and Zn content indicate the paramount effect of these two factors on molecular scale Zn speciation. Further research is required to characterize the link between the fractionation and speciation of Zn and to determine how Zn loading and soil physicochemical properties affect Zn speciation in soils.

  9. Influence of Soil Properties on Soldierless Termite Distribution.

    Science.gov (United States)

    Bourguignon, Thomas; Drouet, Thomas; Šobotník, Jan; Hanus, Robert; Roisin, Yves

    2015-01-01

    In tropical rainforests, termites constitute an important part of the soil fauna biomass, and as for other soil arthropods, variations in soil composition create opportunities for niche partitioning. The aim of this study was twofold: first, we tested whether soil-feeding termite species differ in the foraging substrate; second, we investigated whether soil-feeding termites select their foraging sites to enhance nutrients intake. To do so, we collected termites and analysed the composition and structure of their feeding substrates. Although Anoplotermes-group members are all considered soil-feeders, our results show that some species specifically feed on abandoned termite nests and very rotten wood, and that this substrate selection is correlated with previous stable isotope analyses, suggesting that one component of niche differentiation among species is substrate selection. Our results show that the composition and structure of bare soils on which different termite species foraged do not differ, suggesting that there is no species specialization for a particular type of bare soil. Finally, the bare soil on which termites forage does not differ from random soil samples. Overall, our results suggest that few species of the Anoplotermes-group are specialized toward substrates rich in organic matter, but that the vast majority forage on soil independently of its structural and chemical composition, being ecologically equivalent for this factor.

  10. Soil physical properties influencing the fitting parameters in Philip and Kostiakov infiltration models

    International Nuclear Information System (INIS)

    Mbagwu, J.S.C.

    1994-05-01

    Among the many models developed for monitoring the infiltration process those of Philip and Kostiakov have been studied in detail because of their simplicity and the ease of estimating their fitting parameters. The important soil physical factors influencing the fitting parameters in these infiltration models are reported in this study. The results of the study show that the single most important soil property affecting the fitting parameters in these models is the effective porosity. 36 refs, 2 figs, 5 tabs

  11. Tree species is the major factor explaining C:N ratios in European forest soils

    DEFF Research Database (Denmark)

    Cools, Nathalie; Vesterdal, Lars; De Vos, Bruno

    2014-01-01

    The C:N ratio is considered as an indicator of nitrate leaching in response to high atmospheric nitrogen (N) deposition. However, the C:N ratio is influenced by a multitude of other site-related factors. This study aimed to unravel the factors determining C:N ratios of forest floor, mineral soil...... mineral soil layers it was the humus type. Deposition and climatic variables were of minor importance at the European scale. Further analysis for eight main forest tree species individually, showed that the influence of environmental variables on C:N ratios was tree species dependent. For Aleppo pine...... and peat top soils in more than 4000 plots of the ICP Forests large-scale monitoring network. The first objective was to quantify forest floor, mineral and peat soil C:N ratios across European forests. Secondly we determined the main factors explaining this C:N ratio using a boosted regression tree...

  12. Effect of the edaphic factors and metal content in soil on the diversity of Trichoderma spp.

    Science.gov (United States)

    Racić, Gordana; Körmöczi, Péter; Kredics, László; Raičević, Vera; Mutavdžić, Beba; Vrvić, Miroslav M; Panković, Dejana

    2017-02-01

    Influence of edaphic factors and metal content on diversity of Trichoderma species at 14 different soil sampling locations, on two depths, was examined. Forty-one Trichoderma isolates from 14 sampling sites were determined as nine species based on their internal transcribed spacer (ITS) sequences. Our results indicate that weakly alkaline soils are rich sources of Trichoderma strains. Also, higher contents of available K and P are connected with higher Trichoderma diversity. Increased metal content in soil was not inhibiting factor for Trichoderma species occurrence. Relationship between these factors was confirmed by locally weighted sequential smoothing (LOESS) nonparametric smoothing analysis. Trichoderma strain (Szeged Microbiology Collection (SZMC) 22669) from soil with concentrations of Cr and Ni above remediation values should be tested for its potential for bioremediation of these metals in polluted soils.

  13. Demotivating factors influencing rubber production workers

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Iravani

    2012-01-01

    Full Text Available Motivation is one of the most important factors influencing workers' productivity. An increase in workers' motivation could add more value to organizations' structure and influence the profitability, significantly. In this paper, we study different factors on demotivating workers using questionnaire consist of various questions. The questionnaire is distributed among some employees who work for rubber production units located in Esfahan, Iran. The results of this survey indicate that discrimination on annual job compensation, entrusting responsibilities and unpleasant relationship with family partner are some of the most important factors influencing employees' motivation. While financial factors play important role on increasing employees' motivation, non-financial factors are considered more important.

  14. Soil depth influence on Amazonian ecophysiology

    Science.gov (United States)

    Fagerstrom, I.; Baker, I. T.; Gallup, S.; Denning, A. S.

    2017-12-01

    Models of land-atmosphere interaction are important for simulating present day weather and critical for predictions of future climate. Land-atmosphere interaction models have become increasingly complex in the last 30 years, leading to the need for further studies examining their intricacies and improvement. This research focuses on the effect of variable soil depth on Amazonian Gross Primary Production (GPP), respiration, and their combination into overall carbon flux. We evaluate a control, which has a universal soil depth of 10 meters, with two experiments of variable soil depths. To conduct this study we ran the 3 models for the period 2000-2012, evaluating similarities and differences between them. We focus on the Amazon rain forest, and compare differences in components of carbon flux. Not surprisingly, we find that the main differences between the models arises in regions where the soil depth is dissimilar between models. However, we did not observe significant differences in GPP between known drought, wet, and average years; interannual variability in carbon dynamics was less than anticipated. We also anticipated that differences between models would be most significant during the dry season, but found discrepancies that persisted through the entire annual cycle.

  15. Influence of biochar on the enantioselective behavior of the chiral fungicide metalaxyl in soil

    Science.gov (United States)

    Gámiz, Beatriz; Pignatello, Joseph J.; Hermosín, María Carmen; Cox, Lucía; Celis, Rafael

    2015-04-01

    Chiral pesticides comprise an emerging and important class of organic pollutants currently, accounting for more than a quarter of used pesticides. Consequently, the contamination problems caused by chiral pesticides are concern matter and factors affecting enantioselective processes of chiral pesticides in soil need to be understood. For example, certain soil management practices, such as the use of organic amendments, can affect the enantioselective behavior of chiral pesticides in soils. Recently, biochar (BC), i.e. organic matter subjected to pyrolysis, has been proposed as organic amendment due to beneficial properties such as its high stability against decay in soil environments and its apparent ability to influence the availability of nutrients. BC is considered to be more biologically inert as compared to otherforms of organic carbon. However, its side-effects on the enantioselectivity of processes affecting the fate of chiral pesticides is unknown. The aim of this study was to assess the effect of biochar (BC) on the enantioselectivity of sorption, degradation, and leaching of the chiral fungicide metalaxyl in an agricultural soil. Amending the soil with BC (2% w/w) resulted in 3 times higher sorption of metalaxyl enantiomers compared to unamended soil, but no enantioselectivity in the process was observed. Moreover, both enantiomers showed some resistance to be desorbed in BC-amended soil compared to unamended soil. Dissipation studies revealed that the degradation of metalaxylwas more enantioselective in the unamended soil than in BC-amended soil. In unamended soil, R-metalaxyl(biologically active) and S- metalaxyl had half-lives (t1/2) of 3 and 34 days, respectively. BC enhanced the persistence of both enantiomers in the soil, with R-metalaxyl being degraded faster (t1/2=43 days) than S-metalaxyl (t1/2= 100 days). The leaching of both S-and R-metalaxyl was almost suppressed after amending the soil with BC; less than 10% of the fungicide applied to soil

  16. Influence of Disturbance on Soil Respiration in Biologically Crusted Soil during the Dry Season

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2013-01-01

    Full Text Available Soil respiration (Rs is a major pathway for carbon cycling and is a complex process involving abiotic and biotic factors. Biological soil crusts (BSCs are a key biotic component of desert ecosystems worldwide. In desert ecosystems, soils are protected from surface disturbance by BSCs, but it is unknown whether Rs is affected by disturbance of this crust layer. We measured Rs in three types of disturbed and undisturbed crusted soils (algae, lichen, and moss, as well as bare land from April to August, 2010, in Mu Us desert, northwest China. Rs was similar among undisturbed soils but increased significantly in disturbed moss and algae crusted soils. The variation of Rs in undisturbed and disturbed soil was related to soil bulk density. Disturbance also led to changes in soil organic carbon and fine particles contents, including declines of 60–70% in surface soil C and N, relative to predisturbance values. Once BSCs were disturbed, Q10 increased. Our findings indicate that a loss of BSCs cover will lead to greater soil C loss through respiration. Given these results, understanding the disturbance sensitivity impact on Rs could be helpful to modify soil management practices which promote carbon sequestration.

  17. Dissolved organic carbon (DOC) concentrations in UK soils and the influence of soil, vegetation type and seasonality.

    Science.gov (United States)

    van den Berg, Leon J L; Shotbolt, Laura; Ashmore, Mike R

    2012-06-15

    Given the lack of studies which measured dissolved organic carbon (DOC) over long periods, especially in non-forest habitat, the aim of this study was to expand the existing datasets with data of mainly non-forest sites that were representative of the major soil and habitat types in the UK. A further aim was to predict DOC concentrations from a number of biotic and abiotic explanatory variables such as rainfall, temperature, vegetation type and soil type in a multivariate way. Pore water was sampled using Rhizon or Prenart samplers at two to three week intervals for 1 year. DOC, pH, organic carbon, carbon/nitrogen (C:N) ratios of soils and slope were measured and data on vegetation, soil type, temperature and precipitation were obtained. The majority of the variation in DOC concentrations between the UK sites could be explained by simple empirical models that included annual precipitation, and soil C:N ratio with precipitation being negatively related to DOC concentrations and C:N ratio being positively related to DOC concentrations. Our study adds significantly to the data reporting DOC concentrations in soils, especially in grasslands, heathlands and moorlands. Broad climatic and site factors have been identified as key factors influencing DOC concentrations. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Soil texture and depth influence on the neutron probe calibration

    International Nuclear Information System (INIS)

    Santos, Reginaldo Ferreira; Carlesso, Reimar

    1998-01-01

    The neutron probe is an equipment used on determination of the soil water content, based on the fast neutron attenuation. Therefore, there is a calibration need in the field and, consequently, to verify the soil texture and depth influence for to determining the calibration curves in relation to the water content. The study was developed at Santa Maria's Federal University in a lisimeter group, protected from the rains with transparent plastic. There different soil textures, three depths (10, 30 and 50 cm from the soil surface) and four replicates were used. Linear regression equations between neutron counts and soil water contents were made. The results showed that there was interference of the texture and depth of the soil, analyzed jointly, on the calibration curves, and the observed and estimated values varied form o,02 to 0,06 cm3/cm3 of the soil water content and the correlation coefficients were 0,86 0,95 and 0,89 for clayray, franc-silt-clayey and franc-sandy, respectively. For soil texture and depth, analyzed separately, the differences among the values observed in the field and the estimated ones, varied from 0,0 to 0,02 cm3/cm3 soil water content and presented correlation coefficients between 0,97 and 1,0. (author)

  19. INFLUENCES OF SOIL PROPERTIES ON CHROMIUM (III SORPTION

    Directory of Open Access Journals (Sweden)

    R. Salmasi, F. Salmasi

    2007-07-01

    Full Text Available Soil adsorbing properties reduce sorption ability of the metal, which in turn may influence decision for remediation at contaminated sites. The objective of this study is presentation of a model based on soil properties to estimate the sorption of Cr(III in chromium contaminated soils. Twenty uncontaminated soil samples, with properties similar to the contaminated soils were selected from around of city of Tabriz and treated with Cr as CrCl3. A multiple regression analysis with statgraph software was used to drive an expression that related Cr sorption to common soil properties. The results showed that four soil properties were important in determining the amount of Cr adsorbed by the soils including pH, cation exchange capacity, total inorganic carbon and clay content with nearly 80% variability in Cr sorption and a reasonable level of confidence by this model. The obtained model suggested that Cr(III sorption was enhanced by higher soil pH, more total inorganic carbon, more clay, and higher cation exchange capacity.

  20. Factors Influencing Substance Abuse among Undergraduate ...

    African Journals Online (AJOL)

    The study investigated the factors influencing substance abuse amongundergraduate students in Osun State; Nigeria. A sample of 1, 200undergraduate students were randomly selected from three tertiaryinstitution in Osun State. Factors Influencing Substance Abuse Questionnaire (FISA) was developed by the researcher ...

  1. Factors influencing customer satisfaction with reference and ...

    African Journals Online (AJOL)

    This paper examines factors influencing customer satisfaction with reference and information services in an academic environment. The paper identifies types of reference services in libraries, factors influencing customer satisfaction and dissatisfaction with reference and information services and suggested the way forward ...

  2. Factors Influencing Livelihood Diversification among Rural Farmers ...

    African Journals Online (AJOL)

    This research study was set out to analyze factors influencing rural farmer's engagement in livelihood diversification in the study area. The specific objectives were; to identify the different levels of farmers' engagement in livelihood diversification, determine the socio-demographic factors or forces that influence farmers' ...

  3. Factors Influencing Endometrial Thickness in Postmenopausal Women

    African Journals Online (AJOL)

    Background: Cut‑off values for endometrial thickness (ET) in asymptomatic postmenopausal woman have been standardized. However, there are no comprehensive studies to document how various factors can influence the ET after the age of menopause. Aim: To study the various factors influencing the ET in ...

  4. Sensitivity Analysis of the USLE Soil Erodibility Factor to Its Determining Parameters

    Science.gov (United States)

    Mitova, Milena; Rousseva, Svetla

    2014-05-01

    Soil erosion is recognized as one of the most serious soil threats worldwide. Soil erosion prediction is the first step in soil conservation planning. The Universal Soil Loss Equation (USLE) is one of the most widely used models for soil erosion predictions. One of the five USLE predictors is the soil erodibility factor (K-factor), which evaluates the impact of soil characteristics on soil erosion rates. Soil erodibility nomograph defines K-factor depending on soil characteristics, such as: particle size distribution (fractions finer that 0.002 mm and from 0.1 to 0.002 mm), organic matter content, soil structure and soil profile water permeability. Identifying the soil characteristics, which mostly influence the K-factor would give an opportunity to control the soil loss through erosion by controlling the parameters, which reduce the K-factor value. The aim of the report is to present the results of analysis of the relative weight of these soil characteristics in the K-factor values. The relative impact of the soil characteristics on K-factor was studied through a series of statistical analyses of data from the geographic database for soil erosion risk assessments in Bulgaria. Degree of correlation between K-factor values and the parameters that determine it was studied by correlation analysis. The sensitivity of the K-factor was determined by studying the variance of each parameter within the range between minimum and maximum possible values considering average value of the other factors. Normalizing transformation of data sets was applied because of the different dimensions and the orders of variation of the values of the various parameters. The results show that the content of particles finer than 0.002 mm has the most significant relative impact on the soil erodibility, followed by the content of particles with size from 0.1 mm to 0.002 mm, the class of the water permeability of the soil profile, the content of organic matter and the aggregation class. The

  5. Fatores relacionados à suscetibilidade da erosão em entressulcos sob condições de uso e manejo do solo Factors influencing susceptibility to interrill soil erosion under different land use and management conditions

    Directory of Open Access Journals (Sweden)

    Flávio P. de Oliveira

    2012-04-01

    Full Text Available Neste trabalho foram avaliados fatores relacionados com a suscetibilidade a erosão em entressulcos de um Neossolo Litólico submetido a diferentes intensidades de uso e manejo do solo. O experimento foi realizado em condições de laboratório, utilizando-se amostras deformadas de solo colocadas em parcelas experimentais (0,23 m2 e declividade de 0,09 m m-1. O delineamento experimental utilizado foi em blocos casualizados, em que foram aplicadas chuvas simuladas com intensidade de 100 mm h-1 para os seguintes tratamentos: (I solo cultivado com fumo sob preparo convencional (PC; (II solo cultivado com fumo sob plantio direto (PD e (III solo sob mata nativa (MN. Para avaliar a suscetibilidade a erosão em entressulcos utilizaram-se índices referentes à relação energia cinética total (chuva e escoamento sobre perda de solo, taxa média de desagregação e índice de estabilidade de agregados, cujos resultados mostraram que os fatores relacionados com a suscetibilidade a erosão em entressulcos estão associados não apenas com características e propriedades que conferem coesividade ao solo, mas, também, com condicionantes que afetam a hidráulica do escoamento e, consequentemente, a fase de transporte dos sedimentos.This study evaluated factors related to the suscetibility to the interrill soil erosion in an Entisol subjected to different degrees of soil use and management. The experiment was carried out under laboratory conditions using samples collected from tobacco fields and disturbed soil placed in erosion pans measuring (0.23 m2 with a slope of 0.09 m m-1. The experimental design was in randomized blocks. Simulated rainfall intensity of 100 mm h-1 was applied to the following treatments: (I conventionally tilled soil; (II no-till soil; and (III native forest soil. Total kinetic energy (rainfall and runoff to soil loss, average rate of detachment, and aggregate stability indexes were used to assess susceptibility to interrill erosion

  6. Factors affecting soil erosion in Beijing mountain forestlands | Zhang ...

    African Journals Online (AJOL)

    The role of regions, vegetation types and forest stand density in controlling soil erosion were investigated in Beijing mountain forest, China. The main objective was to develop some models to estimate soil erosion under different forest conditions including regions, vegetation type, and stand density as influenced by artificial ...

  7. Influence of soil pedological properties on termite mound stability

    OpenAIRE

    Jouquet, Pascal; Guilleux, N.; Caner, L.; Chintakunta, S.; Ameline, M.; Shanbhag, R. R.

    2016-01-01

    This study investigated the influence of soil properties on the density and shape of epigeous fungus-growing termite nests in a dry deciduous forest in Karnataka, India. In this environment, Odontotermes obesus produces cathedral shaped mounds. Their density, shape (height and volume) and soil physicochemical properties were analyzed in ferralsol and vertisol environments. No significant difference was observed in O. obesus mound density (n = 2.7 mound ha(-1) on average in the vertisol and fe...

  8. Interspecific Relationships Among Soil Invertebrates Influence Pollutant Effects of Phenanthrene

    DEFF Research Database (Denmark)

    Cortet, J.; Joffre, R.; Elmholt, S.

    2006-01-01

    , nitrogen concentration). The effects of each community on the fate of phenanthrene were also assessed. We hypothesize that phenanthrene affects the population dynamics of mesofauna and soil biological functioning depending on exposure duration, type of community, or both. Results show that phenanthrene...... toxic effects of organic pollutants on mesofauna species and soil biological functioning....... exerted an effect on mesofauna and that the effects on some species, like Folsomia fimetaria, were influenced by the species composition in the mesocosms, the soil layer, and the sampling date. However, the effects of phenanthrene on ergosterol content and organic matter decomposition were...

  9. Influence of the isomerism on the sorption of imazamethabenz-methyl by soil.

    Science.gov (United States)

    Pinna, Maria Vittoria; Pusino, Alba

    2013-04-01

    The sorption of meta and para isomers of the herbicide imazamethabenz-methyl, methyl 6-[(RS)-4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl]-m- or p-toluate, by three soils and soil organic matter, was studied. Sorption isotherms conformed to the Freundlich equation. It was found that pH was the main factor influencing the adsorption in all of the systems. The highest level of sorption was measured on soils with low pH and high organic carbon content. Moreover, at low pH value, the soil rich in smectite clays, favoured the sorption of meta rather than para isomer. The higher affinity of clay surfaces for the meta isomer of the herbicide is due to the stabilization of the meta protonated form by resonance. At all pH values, the sorption on soil organic matter did not differ between two isomers. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Confounding factors in determining causal soil moisture-precipitation feedback

    Science.gov (United States)

    Tuttle, Samuel E.; Salvucci, Guido D.

    2017-07-01

    Identification of causal links in the land-atmosphere system is important for construction and testing of land surface and general circulation models. However, the land and atmosphere are highly coupled and linked by a vast number of complex, interdependent processes. Statistical methods, such as Granger causality, can help to identify feedbacks from observational data, independent of the different parameterizations of physical processes and spatiotemporal resolution effects that influence feedbacks in models. However, statistical causal identification methods can easily be misapplied, leading to erroneous conclusions about feedback strength and sign. Here, we discuss three factors that must be accounted for in determination of causal soil moisture-precipitation feedback in observations and model output: seasonal and interannual variability, precipitation persistence, and endogeneity. The effect of neglecting these factors is demonstrated in simulated and observational data. The results show that long-timescale variability and precipitation persistence can have a substantial effect on detected soil moisture-precipitation feedback strength, while endogeneity has a smaller effect that is often masked by measurement error and thus is more likely to be an issue when analyzing model data or highly accurate observational data.

  11. Socio-Economic Factors Assessment Affecting the Adoption of Soil Conservation Technologies on Rwenzori Mountain

    Directory of Open Access Journals (Sweden)

    Nabalegwa Wambede Muhamud

    2015-06-01

    Full Text Available This study analysed the role of socio-economic factors in influencing farmers’ adoption to soil conservation technologies in Bugoye Sub-county, Rwenzori Mountain. A cross sectional household survey design was used in this study, using systematic sampling to obtain 150 household samples. Qualitative analysis and chi-square tests were used to analyze these data. Results indicated that only 54% of the sampled households have adopted soil conservation, and revealed that eight of the nine factors significantly influenced farmers’ adoption, which are slope, farm size, farm distance from home, education level, family income, training, membership to NGOs, and credit accessibility. Only family size was insignificant. Other constraints are labour demands, cost of conservation work, land fragmentation, crop pests, and the limited agricultural extension services. It is recommended to perform training for farmers on designing soil conservation structures. Policies for empowering farmers with extra income are crucial to increase the adoption of soil conservation efforts.

  12. Variability of the soil-to-plant radiocaesium transfer factor for Japanese soils predicted with soil and plant properties.

    Science.gov (United States)

    Uematsu, Shinichiro; Vandenhove, Hildegarde; Sweeck, Lieve; Van Hees, May; Wannijn, Jean; Smolders, Erik

    2016-03-01

    Food chain contamination with radiocaesium (RCs) in the aftermath of the Fukushima accident calls for an analysis of the specific factors that control the RCs transfer. Here, soil-to-plant transfer factors (TF) of RCs for grass were predicted from the potassium concentration in soil solution (mK) and the Radiocaesium Interception Potential (RIP) of the soil using existing mechanistic models. The mK and RIP were (a) either measured for 37 topsoils collected from the Fukushima accident affected area or (b) predicted from the soil clay content and the soil exchangeable potassium content using the models that had been calibrated for European soils. An average ammonium concentration was used throughout in the prediction. The measured RIP ranged 14-fold and measured mK varied 37-fold among the soils. The measured RIP was lower than the RIP predicted from the soil clay content likely due to the lower content of weathered micas in the clay fraction of Japanese soils. Also the measured mK was lower than that predicted. As a result, the predicted TFs relying on the measured RIP and mK were, on average, about 22-fold larger than the TFs predicted using the European calibrated models. The geometric mean of the measured TFs for grass in the affected area (N = 82) was in the middle of both. The TFs were poorly related to soil classification classes, likely because soil fertility (mK) was obscuring the effects of the soil classification related to the soil mineralogy (RIP). This study suggests that, on average, Japanese soils are more vulnerable than European soils at equal soil clay and exchangeable K content. The affected regions will be targeted for refined model validation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Mapping Soil Erosion Factors and Potential Erosion Risk for the National Park "Central Balkan"

    Science.gov (United States)

    Ilieva, Diliana; Malinov, Ilia

    2014-05-01

    Soil erosion is widely recognised environmental problem. The report aims at presenting the main results from assessment and mapping of the factors of sheet water erosion and the potential erosion risk on the territory of National Park "Central Balkan". For this purpose, the Universal Soil Loss Equation (USLE) was used for predicting soil loss from erosion. The influence of topography (LS-factor) and soil erodibility (K-factor) was assessed using small-scale topographic and soil maps. Rainfall erosivity (R-factor) was calculated from data of rainfalls with amounts exceeding 9.5 mm from 14 hydro-meteorological stations. The values of the erosion factors (R, K and LS) were presented for the areas of forest, sub-alpine and alpine zones. Using the methods of GIS, maps were plotted presenting the area distribution among the classes of the soil erosion factors and the potential risk in the respective zones. The results can be used for making accurate decisions for soil conservation and sustainable land management in the park.

  14. Plant diversity and plant identity influence Fusarium communities in soil.

    Science.gov (United States)

    LeBlanc, Nicholas; Kinkel, Linda; Kistler, H Corby

    2017-01-01

    Fusarium communities play important functional roles in soil and in plants as pathogens, endophytes, and saprotrophs. This study tests how rhizosphere Fusarium communities may vary with plant species, changes in the diversity of the surrounding plant community, and soil physiochemical characteristics. Fusarium communities in soil associated with the roots of two perennial prairie plant species maintained as monocultures or growing within polyculture plant communities were characterized using targeted metagenomics. Amplicon libraries targeting the RPB2 locus were generated from rhizosphere soil DNAs and sequenced using pyrosequencing. Sequences were clustered into operational taxonomic units (OTUs) and assigned a taxonomy using the Evolutionary Placement Algorithm. Fusarium community composition was differentiated between monoculture and polyculture plant communities, and by plant species in monoculture, but not in polyculture. Taxonomic classification of the Fusarium OTUs showed a predominance of F. tricinctum and F. oxysporum as well of the presence of a clade previously only found in the Southern Hemisphere. Total Fusarium richness was not affected by changes in plant community richness or correlated with soil physiochemical characteristics. However, OTU richness within two predominant phylogenetic lineages within the genus was positively or negatively correlated with soil physiochemical characteristics among samples within each lineage. This work shows that plant species, plant community richness, and soil physiochemical characteristics may all influence the composition and richness of Fusarium communities in soil.

  15. Influence of cracking clays on satellite estimated and model simulated soil moisture

    Directory of Open Access Journals (Sweden)

    Y. Y. Liu

    2010-06-01

    Full Text Available Vertisols are clay soils that are common in the monsoonal and dry warm regions of the world. One of the characteristics of these soil types is to form deep cracks during periods of extended dry, resulting in significant variation of the soil and hydrologic properties. Understanding the influence of these varying soil properties on the hydrological behavior of the system is of considerable interest, particularly in the retrieval or simulation of soil moisture. In this study we compare surface soil moisture (θ in m3 m−3 retrievals from AMSR-E using the VUA-NASA (Vrije Universiteit Amsterdam in collaboration with NASA algorithm with simulations from the Community Land Model (CLM over vertisol regions of mainland Australia. For the three-year period examined here (2003–2005, both products display reasonable agreement during wet periods. During dry periods however, AMSR-E retrieved near surface soil moisture falls below values for surrounding non-clay soils, while CLM simulations are higher. CLM θ are also higher than AMSR-E and their difference keeps increasing throughout these dry periods. To identify the possible causes for these discrepancies, the impacts of land use, topography, soil properties and surface temperature used in the AMSR-E algorithm, together with vegetation density and rainfall patterns, were investigated. However these do not explain the observed θ responses. Qualitative analysis of the retrieval model suggests that the most likely reason for the low AMSR-E θ is the increase in soil porosity and surface roughness resulting from cracking of the soil. To quantitatively identify the role of each factor, more in situ measurements of soil properties that can represent different stages of cracking need to be collected. CLM does not simulate the behavior of cracking soils, including the additional loss of moisture from the soil continuum during drying and the infiltration into cracks during rainfall events

  16. Net carbon allocation in soybean seedlings as influenced by soil water stress at two soil temperatures

    International Nuclear Information System (INIS)

    McCoy, E.L.; Boersma, L.; Ekasingh, M.

    1990-01-01

    The influence of water stress at two soil temperatures on allocation of net photoassimilated carbon in soybean (Glycine max [L.] Merr.) was investigated using compartmental analysis. The experimental phase employed classical 14 C labeling methodology with plants equilibrated at soil water potentials of -0.04, -0.25 and -0.50 MPa; and soil temperatures of 25 and 10C. Carbon immobilization in the shoot apex generally followed leaf elongation rates with decreases in both parameters at increasing water stress at both soil temperatures. However, where moderate water stress resulted in dramatic declines in leaf elongation rates, carbon immobilization rates were sharply decreased only at severe water stress levels. Carbon immobilization was decreased in the roots and nodules of the nonwater stressed treatment by the lower soil temperature. This relation was reversed with severe water stress, and carbon immobilization in the roots and nodules was increased at the lower soil temperature. Apparently, the increased demand for growth and/or carbon storage in these tissues with increased water stress overcame the low soil temperature limitations. Both carbon pool sizes and partitioning of carbon to the sink tissues increased with moderate water stress at 25C soil temperature. Increased pool sizes were consistent with whole plant osmotic adjustment at moderate water stress. Increased partitioning to the sinks was consistent with carbon translocation processes being less severely influenced by water stress than is photosynthesis

  17. Influence of extractable soil manganese on oxidation capacity of different soils in Korea

    Science.gov (United States)

    Chon, Chul-Min; Kim, Jae Gon; Lee, Gyoo Ho; Kim, Tack Hyun

    2008-08-01

    We examined the relationship between soil oxidation capacity and extractable soil manganese, iron oxides, and other soil properties. The Korean soils examined in this study exhibited low to medium Cr oxidation capacities, oxidizing 0.00-0.47 mmol/kg, except for TG-4 soils, which had the highest capacity for oxidizing added Cr(III) [>1.01 mmol/kg of oxidized Cr(VI)]. TG and US soils, with high Mn contents, had relatively high oxidation capacities. The Mn amounts extracted by dithionite-citrate-bicarbonate (DCB) (Mnd), NH2OH·HCl (Mnh), and hydroquinone (Mnr) were generally very similar, except for the YS1 soils, and were well correlated. Only small proportions of either total Mn or DCB-extractable Mn were extracted by NH2OH·HCl and hydroquinone in the YS1 soils, suggesting inclusion of NH2OH·HCl and hydroquinone-resistant Mn oxides, because these extractants are weaker reductants than DCB. No Cr oxidation test results were closely related to total Mn concentrations, but Mnd, Mnh, and Mnr showed a relatively high correlation with the Cr tests ( r = 0.655-0.851; P Mnh were better correlated with the Cr oxidation tests than was the Mnr concentration, suggesting that the oxidation capacity of our soil samples can be better explained by Mnd and Mnh than by Mnr. The first component in principal components analysis indicated that extractable soil Mn was a main factor controlling net Cr oxidation in the soils. Total soil Mn, Fe oxides, and the clay fraction are crucial for predicting the mobility of pollutants and heavy metals in soils. The second principal component indicated that the presence of Fe oxides in soils had a significant relationship with the clay fraction and total Mn oxide, and was also related to heavy-metal concentrations (Zn, Cd, and Cu, but not Pb).

  18. Influence of management history and landscape variables on soil organic carbon and soil redistribution

    Science.gov (United States)

    Venteris, E.R.; McCarty, G.W.; Ritchie, J.C.; Gish, T.

    2004-01-01

    Controlled studies to investigate the interaction between crop growth, soil properties, hydrology, and management practices are common in agronomy. These sites (much as with real world farmland) often have complex management histories and topographic variability that must be considered. In 1993 an interdisiplinary study was started for a 20-ha site in Beltsville, MD. Soil cores (271) were collected in 1999 in a 30-m grid (with 5-m nesting) and analyzed as part of the site characterization. Soil organic carbon (SOC) and 137Cesium (137Cs) were measured. Analysis of aerial photography from 1992 and of farm management records revealed that part of the site had been maintained as a swine pasture and the other portion as cropped land. Soil properties, particularly soil redistribution and SOC, show large differences in mean values between the two areas. Mass C is 0.8 kg m -2 greater in the pasture area than in the cropped portion. The pasture area is primarily a deposition site, whereas the crop area is dominated by erosion. Management influence is suggested, but topographic variability confounds interpretation. Soil organic carbon is spatially structured, with a regionalized variable of 120 m. 137Cs activity lacks spatial structure, suggesting disturbance of the profile by animal activity and past structures such as swine shelters and roads. Neither SOC nor 137Cs were strongly correlated to terrain parameters, crop yields, or a seasonal soil moisture index predicted from crop yields. SOC and 137Cs were weakly correlated (r2 ???0.2, F-test P-value 0.001), suggesting that soil transport controls, in part, SOC distribution. The study illustrates the importance of past site history when interpreting the landscape distribution of soil properties, especially those strongly influenced by human activity. Confounding variables, complex soil hydrology, and incomplete documentation of land use history make definitive interpretations of the processes behind the spatial distributions

  19. The influence of soil type and climate on the uptake of radionuclides into wheat

    International Nuclear Information System (INIS)

    Mitchell, N.G.

    1992-03-01

    The study investigated the uptake by winter wheat of radionuclides deposited onto the soil surface following a hypothetical accidental release to atmosphere from a nuclear power station. A series of lysimeters were filled with four soil types characteristic of wheat growing areas of Europe. Four radionuclides ( 137 Cs, 144 Ce, 106 Ru, 125 Sb) were watered onto the soil surface and the subsequent contamination of winter wheat crops was monitored over two seasons. Subsidiary experiments considered: effects of ploughing and pot size on root uptake; movement of radionuclides in soil profiles; soil contamination of wheat plants and of grain leaving the field; the influence of climate on root uptake; and, the availability of radionuclides. Compared with the literature, this study found a smaller range of transfer factors appropriate to agricultural soils that predominate in the wheat growing areas of the EEC. The use of pots or tubes to investigate soil-to-plant transfer was justified. The study showed that resuspension of radionuclides bound to soil particles must be considered when assessing soil-to-plant transfer. It was demonstrated that the contribution of soil-bound activity to the radionuclide content of combine harvested grain is underestimated in existing dose assessment methodologies by at least an order of magnitude on average and by over two orders of magnitude in extreme cases. Climatic conditions simulated in a growth chamber had little impact on radionuclide transfer. The relative availability of radionuclides for extraction by ammonium acetate did not reflect percentage transfer to grain. Ploughing reduced uptake by winter wheat, resulted in different patterns of transfer between cultivation treatments and influenced the distribution of activity between grain and straw. Results of this work were used in the development of a multi-compartmental time-dependent model called WHEAT which predicts radionuclide transfer from soil to winter wheat. (author)

  20. Headcut erosive regimes influenced by groundwater on disturbed agricultural soils.

    Science.gov (United States)

    Rockwell, D L

    2011-02-01

    A series of simulated rainfall experiments, testing several soils and slope gradients in a 10 m x 0.8m laboratory flume, displayed close correlations between initial development of a water table at a 10 cm depth and highly erosive headcut formation. On some soils and gradients, highly erosive headcuts formed consistently and predictably within minutes or seconds of initial water table rise. However, headcuts alone were not good indicators of increased erosion. In most experiments some headcuts formed early, often when surface hydraulic parameter values reached established rill initiation thresholds, but resulted in little or no erosion increase. Later, at initial water table rise, other headcuts formed coincident with major erosion increase, often with surface hydraulic values then less than rill initiation thresholds. On the four soils tested, highly erosive headcuts never formed without groundwater development, except on steep 9 ° slopes. Common visual indicators such as headcut morphology and headcut advance rates were not effective means of determining either erosion or the existence of groundwater. Only local monitoring of subsurface moisture conditions with micro-standpipes and TDR aided in determining headcut processes and erosive regimes. Groundwater-influenced headcut formation was likely caused by increased soil pore-water pressures and decreased soil shear strengths in surface rainflow, not by sapping or seepage from the soil matrix. Highly erosive headcuts can thus form under common agricultural conditions where reductions in permeability, such as plow pans, exist near the surface--without the need for saturated soils. Headcut erosive regimes were also significantly influenced by soil type and slope gradient, with the greatest effects of groundwater on moderate slopes and fairly permeable soils. Copyright © 2010. Published by Elsevier Ltd.

  1. SOIL FORMATION BY ECOLOGICAL FACTORS: CRITICAL REVIEW

    OpenAIRE

    Saeed Zeraat Kar; Aydin Berenjian

    2013-01-01

    Regolith is the term we give parent material that has been weathered. The regolith consists of weathered bedrock near the surface including the soil layer. In the Iranian soil layer we will find: decayed parent materials, decaying plant material, decaying animal matter (manure) along with vegetation. Results of the present study show us that methods stimulating natural fertility in Iran includes composting-adds humus layer, drip irrigation-balances illuviation and eluviation in arid regions, ...

  2. Which Factors Determine Metal Accumulation in Agricultural Soils in the Severely Human-Coupled Ecosystem?

    Science.gov (United States)

    Xu, Li; Cao, Shanshan; Wang, Jihua; Lu, Anxiang

    2016-05-17

    Agricultural soil is typically an important component of urban ecosystems, contributing directly or indirectly to the general quality of human life. To understand which factors influence metal accumulation in agricultural soils in urban ecosystems is becoming increasingly important. Land use, soil type and urbanization indicators all account for considerable differences in metal accumulation in agricultural soils, and the interactions between these factors on metal concentrations were also examined. Results showed that Zn, Cu, and Cd concentrations varied significantly among different land use types. Concentrations of all metals, except for Cd, were higher in calcareous cinnamon soil than in fluvo-aquic soil. Expansion distance and road density were adopted as urbanization indicators, and distance from the urban center was significantly negatively correlated with concentrations of Hg, and negatively correlated with concentrations of Zn, and road density was positively correlated with Cd concentrations. Multivariate analysis of variance indicated that Hg concentration was significantly influenced by the four-way interaction among all factors. The results in this study provide basic data to support the management of agricultural soils and to help policy makers to plan ahead in Beijing.

  3. Key biogeochemical factors affecting soil carbon storage in Posidonia meadows

    KAUST Repository

    Serrano, Oscar

    2016-08-15

    Biotic and abiotic factors influence the accumulation of organic carbon (C-org) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2-4 m depth) accumulated 3- to 4-fold higher C-org stocks (averaging 6.3 kg C-org m(-2) at 3- to 4-fold higher rates (12.8 gC(org) m(-2) yr(-1) ) compared to meadows closer to the deep limits of distribution (at 6-8 m depth; 1.8 kg C-org m(-2) and 3.6 g C-org m(-2) yr(-1) . In shallower meadows, C-org stocks were mostly derived from seagrass detritus (88% in average) compared to meadows closer to the deep limit of distribution (45% on average). In addition, soil accumulation rates and fine-grained sediment content (< 0.125 mm) in shallower meadows (2.0 mm yr(-1) and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2 mm yr(-1) and 5 %, respectively). The C-org stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg C-org m(-2) and 1.2 g C-org m(-2) yr(-1)were 3- to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8- and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypothesis that Corg storage in seagrass soils is influenced by interactions of biological (e.g., meadow productivity, cover and density), chemical (e.g., recalcitrance of Corg stocks) and physical (e.g., hydrodynamic energy and soil accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats.

  4. Community Factors Influencing Birth Spacing among Married ...

    African Journals Online (AJOL)

    AJRH Managing Editor

    level factors on birth spacing behaviour in Uganda and Zimbabwe, to ... environments as potential influences on birth spacing ..... health: multivariable cross-country analysis, MACRO ... Equity monitoring for social marketing: Use of wealth.

  5. Factors Influencing Self Employment Media Service Providers ...

    African Journals Online (AJOL)

    Factors Influencing Self Employment Media Service Providers among Tertiary ... role stereotype and common business practices on media self employment in ... Sex, Psycho-social Characteristics, self Employment, Providing Media Services.

  6. Influence of Macroeconomic Factors on Residential Property ...

    African Journals Online (AJOL)

    Sultan

    exerted by macroeconomic factors on residential property returns in Abuja. The backward .... explanatory power and positive influence of employment and ...... Project. Management In Property Development: the Nigeria experience. Ibadan:.

  7. Factors Influencing Adoption of Cocoa Technologies Disseminated ...

    African Journals Online (AJOL)

    Factors Influencing Adoption of Cocoa Technologies Disseminated by Olam Organisation in ... Journal of Agricultural Research and Development ... level, household size, no of farm family assisting on the farm, management system adopted, ...

  8. Assessment of Factors Influencing Beneficiary Participation in ...

    African Journals Online (AJOL)

    ISSN 0794-5698. Assessment of Factors Influencing Beneficiary Participation in Fadama II Project ... project implementation (80%) in the stages of project development. Women .... the project as they appeared to have more family burden to ...

  9. Chapter 7. Assessing soil factors in wildland improvement programs

    Science.gov (United States)

    Arthur R. Tiedemann; Carlos F. Lopez

    2004-01-01

    Soil factors are an important consideration for successful wildland range development or improvement programs. Even though many soil improvement and amelioration practices are not realistic for wildlands, their evaluation is an important step in selection of adapted plant materials for revegetation. This chapter presents information for wildland managers on: the...

  10. Factors influencing detail detectability in radiologic imaging

    International Nuclear Information System (INIS)

    Gurvich, A.M.

    1985-01-01

    The detectability of various details is estimated quantitatively from the essential technical parameters of the imaging system and additional influencing factors including viewing of the image. The analysis implies the formation of the input radiation distribution (contrast formation, influence of kVp). Noise, image contrast (gamma), modulation transfer function and contrast threshold of the observer are of different influence on details of different size. Thus further optimization of imaging systems and their adaption to specific imaging tasks are facilitated

  11. Accumulation of Heavy Metals in Roadside Soil in Urban Area and the Related Impacting Factors.

    Science.gov (United States)

    Wang, Meie; Zhang, Haizhen

    2018-05-24

    Heavy metal contamination in roadside soil due to traffic emission has been recognized for a long time. However, seldom has been reported regarding identification of critical factors influencing the accumulation of heavy metals in urban roadside soils due to the frequent disturbances such as the repair of damaged roads and green belt maintanance. Heavy metals in the roadside soils of 45 roads in Xihu district, Hangzhou city were investigated. Results suggested the accumulation of Cu, Pb, Cd, Cr, and Zn in roadside soil was affected by human activity. However, only two sites had Pb and Zn excessing the standards for residential areas, respectively, according to Chinese Environmental Quality Standards for soils. The concentrations of Cu, Pb, Cd, and Zn were significantly and positively correlated to soil pH and organic matter. An insignificant correlation between the age of the roads or vegetation cover types and the concentration of heavy metals was found although they were reported closely relating to the accumulation of heavy metals in roadside soils of highways. The highest Pb, Cd, and Cr taking place in sites with heavy traffic and significant differences in the concentrations of Cu, Pb, Cd, and Zn among the different categories of roads suggested the contribution of traffic intensity. However, it was difficult to establish a quantitative relationship between traffic intensity and the concentrations of heavy metals in the roadside soil. It could be concluded that impaction of traffic emission on the accumulation of heavy metals in roadside soils in urban area was slight and soil properties such as pH and organic matters were critical factors influencing the retention of heavy metals in soils.

  12. ENERGY EFFICIENCY. TRENDS AND INFLUENCE FACTORS

    Directory of Open Access Journals (Sweden)

    Zizi GOSCHIN

    2006-12-01

    Full Text Available Energy efficiency is correlated with many factors of influence: Gross National Income per capita, energy imports (% of energy use, renewable combustible and waste (% of total, energy use per capita, services as % of GDP and others. In this paper we are testing a model of piecewise linear regression with breakpoint in order to measure the influence of these factors on the variation of GDP per unit of energy use in Europe in the year 2003.

  13. Factors Influencing Title VII Bilingual Program Institutionalization.

    Science.gov (United States)

    Lewis, Gerald R.; And Others

    1985-01-01

    This study of the primary restraining and driving forces that influence Title VII bilingual education programs found the external environment, the local community, to be the main factor influencing institutionalization and self-renewal. The internal environment--the local school, and the local school's organization or central office, school board,…

  14. Influence of Parent Material and Topography on some Soil ...

    African Journals Online (AJOL)

    Selected physical and chemical properties and nutrient ratios on three landscape positions (interfluve crest, middle slope and foot slope) were examined on soils formed on banded gneiss and quartzite schist parent materials. Parent material significantly (p<0.05) influenced gravel, coarse sand and copper contents in the ...

  15. Factors influencing radon attenuation by tailing covers

    International Nuclear Information System (INIS)

    Silker, W.B.; Rogers, V.C.

    1981-07-01

    The US NRC, in its Generic Environmental Impact Statement on uranium milling has specified that the radon flux escaping a uranium mill tailings pile will be reduced to pCi/m 2 s by application of covering layers of soils and clays. These covers present a radon diffusion barrier, which sufficiently increases the time required for radon passage from the tailings to the atmosphere to allow for decay of 222 Rn within the cover. The depth of cover necessary to reduce the escaping radon flux to the prescribed level is to be determined by calculation, and requires precise knowledge of the radon diffusion coefficient in the covering media. A Radon Attenuation Test Facility was developed to determine rates of radon diffusion through candidate cover materials. This paper describes this facility and its application for determining the influence of physical properties of the soil column on the radon diffusion coefficient

  16. What Factors Influence Wind Perceptions

    Science.gov (United States)

    Stein, Tatiana

    Over the last decade, wind power has emerged as a possible source of energy and has attracted the attention of homeowners and policy makers worldwide. Many technological hurdles have been overcome in the last few years that make this technology feasible and economical. The United States has added more wind power than any other type of electric generation in 2012. Depending on the location, wind resources have shown to have the potential to offer 20% of the nation's electricity; a single, large wind turbine has the capacity to produce enough electricity to power 350 homes. Throughout the development of wind turbines, however, energy companies have seen significant public opposition towards the tall white structures. The purpose of this research was to measure peoples' perceptions on wind turbine development throughout their growth, from proposal to existing phase. Three hypotheses were developed based on the participant's political affiliation, proximity and knowledge of wind turbines. To validate these hypotheses, participants were asked an array of questions regarding their perception on economic, environmental, and social impacts of wind turbines with an online service called Amazon Mechanical Turk. The responses were from residents living in the United States and required them to provide their zip code for subsequent analysis. The analysis from the data obtained suggests that participants are favorable towards wind turbine development and would be supportive of using the technology in their community. Political affiliation and proximity to the nearest wind turbine in any phase of development (proposal, construction, existing) were also analyzed to determine if they had an effect on a person's overall perception on wind turbines and their technology. From the analysis, political affiliation was seen to be an indirect factor to understanding favorability towards wind turbines; the more liberal you are, the more supportive you will be towards renewable energy use

  17. Elucidating key factors affecting radionuclide aging in soils

    Energy Technology Data Exchange (ETDEWEB)

    Roig, M. [Universitat Politecnica Catalunya, Institut de Tecniques Energetiques, Barcelona (Spain); Rigola, A.; Vidal, M.; Rauret, G. [Barcelona Univ., Dept. de Quimica Analitica (Spain)

    2004-07-01

    Mechanistic studies allow at present to describe the processes governing the short-term interaction of radiostrontium and radiocaesium in soils. The initial sorption step can be described through the estimation of the soil-soil solution distribution coefficient from soil parameters, as cationic exchange capacity, radiocaesium interception potential and concentration of competing ions in the soil solution. After the initial soil-radionuclide interaction, a fraction of radionuclide is no longer available for exchange with the solution, and it remains fixed in the solid fraction. At present, the initial fixed fraction of a radionuclide in a given soil cannot be predicted from soil properties. Besides, little is known about soil and environmental factors (e.g., temperature; hydric regime) provoking the increase in the fixed fraction with time, the so-called aging process. This process is considered to control the reduction of food contamination with time at contaminated scenarios. Therefore, it is crucial to be able to predict the radionuclide aging in the medium and long term for a better risk assessment, especially when a decision has to be made between relying on natural attenuation versus implementing intervention actions. Here we study radiostrontium and radiocaesium aging in a set of soils, covering a wide range of soil types of contrasting properties (e.g., loamy calcareous; podzol; chernozem, organic). Three factors are separately and simultaneously tested: time elapsed since contamination, temperature and hydric regime. Changes in the radionuclide fixed fraction are estimated with a leaching test based on the use of a mild extractant solution. In addition to this, secondary effects on the radiocaesium interception potential in various soils are also considered. (author)

  18. Soil components that influence the chemical behavior of 239Pu

    International Nuclear Information System (INIS)

    Nishita, H.; Hamilton, M.

    1978-08-01

    Soil components that influence the extractability of 239 Pu from an artificially contaminated kaolinitic soil in relation to pH have been examined. This was done by using an equilibrium batch technique with CH 3 COOH--NH 4 OH and HNO 3 --NaOH extracting systems. Soil organic matter and free iron oxides had an appreciable effect depending on the pH and the extracting system. The free silica and alumina and amorphous alumino-silicates had lesser influence. With the untreated soil (control), the CH 3 COOH--NH 4 OH system generally extracted more 239 Pu than did the HNO 3 --NaOH system in the acidic pH range, whereas the latter system extracted markedly greater amounts of it in the alkaline pH range. With the soil from which the organic matter was removed, the CH 3 COOH--NH 4 OH system extracted appreciably greater amounts of 239 Pu than the HNO 3 --NaOH system in the acidic pH range, but there was only little, if any, difference between the two extracting systems in the alkaline pH range. The causes and the implications of these results are discussed

  19. How do peat type, sand addition and soil moisture influence the soil organic matter mineralization in anthropogenically disturbed organic soils?

    Science.gov (United States)

    Säurich, Annelie; Tiemeyer, Bärbel; Don, Axel; Burkart, Stefan

    2017-04-01

    Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. As a consequence of both drainage induced mineralization and anthropogenic sand mixing, large areas of former peatlands under agricultural use contain soil organic carbon (SOC) at the boundary between mineral and organic soils. Studies on SOC dynamics of such "low carbon organic soils" are rare as the focus of previous studies was mainly either on mineral soils or "true" peat soil. However, the variability of CO2 emissions increases with disturbance and therefore, we have yet to understand the reasons behind the relatively high CO2 emissions of these soils. Peat properties, soil organic matter (SOM) quality and water content are obviously influencing the rate of CO2 emissions, but a systematic evaluation of the hydrological and biogeochemical drivers for mineralization of disturbed peatlands is missing. With this incubation experiment, we aim at assessing the drivers of the high variability of CO2 emissions from strongly anthropogenically disturbed organic soil by systematically comparing strongly degraded peat with and without addition of sand under different moisture conditions and for different peat types. The selection of samples was based on results of a previous incubation study, using disturbed samples from the German Agricultural Soil Inventory. We sampled undisturbed soil columns from topsoil and subsoil (three replicates of each) of ten peatland sites all used as grassland. Peat types comprise six fens (sedge, Phragmites and wood peat) and four bogs (Sphagnum peat). All sites have an intact peat horizon that is permanently below groundwater level and a strongly disturbed topsoil horizon. Three of the fen and two of the bog sites have a topsoil horizon altered by sand-mixing. In addition the soil profile was mapped and samples for the determination of soil hydraulic properties were collected. All 64 soil columns (including four additional reference samples) will be installed

  20. Environmental and management influences on temporal variability of near saturated soil hydraulic properties☆

    Science.gov (United States)

    Bodner, G.; Scholl, P.; Loiskandl, W.; Kaul, H.-P.

    2013-01-01

    Structural porosity is a decisive property for soil productivity and soil environmental functions. Hydraulic properties in the structural range vary over time in response to management and environmental influences. Although this is widely recognized, there are few field studies that determine dominant driving forces underlying hydraulic property dynamics. During a three year field experiment we measured temporal variability of soil hydraulic properties by tension infiltrometry. Soil properties were characterized by hydraulic conductivity, effective macroporosity and Kosugi's lognormal pore size distribution model. Management related influences comprised three soil cover treatment (mustard and rye vs. fallow) and an initial mechanical soil disturbance with a rotary harrow. Environmental driving forces were derived from meteorological and soil moisture data. Soil hydraulic parameters varied over time by around one order of magnitude. The coefficient of variation of soil hydraulic conductivity K(h) decreased from 69.5% at saturation to 42.1% in the more unsaturated range (− 10 cm pressure head). A slight increase in the Kosugi parameter showing pore heterogeneity was observed under the rye cover crop, reflecting an enhanced structural porosity. The other hydraulic parameters were not significantly influenced by the soil cover treatments. Seedbed preparation with a rotary harrow resulted in a fourfold increase in macroporosity and hydraulic conductivity next to saturation, and homogenized the pore radius distribution. Re-consolidation after mechanical loosening lasted over 18 months until the soil returned to its initial state. The post-tillage trend of soil settlement could be approximated by an exponential decay function. Among environmental factors, wetting-drying cycles were identified as dominant driving force explaining short term hydraulic property changes within the season (r2 = 0.43 to 0.59). Our results suggested that beside considering average

  1. Transfer factors of 134Cs for olive and orange trees grown on different soils

    International Nuclear Information System (INIS)

    Skarlou, V.; Nobeli, C.; Anoussis, J.; Haidouti, C.; Papanicolaou, E.

    1999-01-01

    Transfer factors (TF) of 134 Cs to olive and citrus trees grown on two different soils, were determined for a 3-year greenhouse experiment. Two-year-old trees were transplanted with their entire rootball into large pots containing the contaminated soil (110 kg pot -1 ). The soil was transferred to each pot in layers on the top of which 134 Cs as CsCl was dripped (18.5 MBq pot -1 ). For both evergreen trees, soil type significantly influenced radiocaesium transfer. 134 Cs concentration was lower for the calcareous-heavy soil than for the acid-light soil. Transfer factors of orange trees were higher than those of olive trees in the acid-light soil. Although a significant amount of 134 Cs was measured in olives grown on the acid-light soil, no 134 Cs was detected in the unprocessed olive oil when an oil fraction (5% f.w.) was extracted. On the contrary the edible part of the oranges showed the highest 134 Cs concentration of all plant parts. The relationship between 134 Cs uptake and potassium content in the different plant compartments was also studied when selected trees were cut down. The potassium concentration in the plants was not significantly different between the trees growing in the two types of soil in spite of the big differences in the 134 Cs uptake in the two soils. TF values and potassium content in the different plant compartments of each tree were highly correlated. For both crops transfer factors as well as potassium content were the highest in the developing plant parts (new leaves and branches, flowers). The transfer factors of 134 Cs for the studied trees are in the same order of magnitude as the values of annual crops grown under similar conditions. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. Influence of soil amendments made from digestate on soil physics and the growth of spring wheat

    Science.gov (United States)

    Dietrich, Nils; Knoop, Christine; Raab, Thomas; Krümmelbein, Julia

    2016-04-01

    Every year 13 million tons of organic wastes accumulate in Germany. These wastes are a potential alternative for the production of energy in biogas plants, especially because the financial subventions for the cultivation of renewable resources for energy production were omitted in 2014. The production of energy from biomass and organic wastes in biogas plants results in the accumulation of digestate and therefore causes the need for a sustainable strategy of the utilization of these residues. Within the scope of the BMBF-funded project 'VeNGA - Investigations for recovery and nutrient use as well as soil and plant-related effects of digestate from waste fermentation' the application of processed digestate as soil amendments is examined. Therefore we tested four different mechanical treatment processes (rolled pellets, pressed pellets, shredded compost and sieved compost) to produce soil amendments from digestate with regard to their impact on soil physics, soil chemistry and the interactions between plants and soil. Pot experiments with soil amendments were performed in the greenhouse experiment with spring wheat and in field trials with millet, mustard and forage rye. After the first year of the experiment, preliminary results indicate a positive effect of the sieved compost and the rolled pellets on biomass yield of spring wheat as compared to the other variations. First results from the Investigation on soil physics show that rolled pellets have a positive effect on the soil properties by influencing size and distribution of pores resulting in an increased water holding capacity. Further ongoing enhancements of the physical and chemical properties of the soil amendments indicate promising results regarding the ecological effects by increased root growth of spring wheat.

  3. Co-contaminants and factors affecting the sorption behaviour of two sulfonamides in pasture soils

    International Nuclear Information System (INIS)

    Srinivasan, Prakash; Sarmah, Ajit K.; Manley-Harris, Merilyn

    2013-01-01

    We investigated the effect of soil pH, organic carbon, ionic strength and steroid hormones on the sorption of sulfamethoxazole (SMO) and sulfachloropyridazine (SCP) in three pastoral soils of New Zealand. A model linking sorbate speciation with species-specific sorption coefficients describing the pH dependence of the apparent sorption coefficients was used to derive the fraction of each species of SMO. All soils displayed a decrease in sorption when pH was increased, with SMO exhibiting the highest sorption at pH 2. The cationic form of SMO appeared to sorb more close to pH ≥ pK a1 and, when pH ≥ pK a2 (6.5, 7.5 and 8.5) the anionic species seems to dominate, however, its sorption affinity to all soils was low. SMO sorption was affected by ionic strengths and organic carbon content, while the presence of hormones showed only a subtle decrease in SCP sorption in a selected model pasture soil. -- Highlights: •The effect of OC content on sulfamethoxazole sorption is nullified by the pH effect. •Steroid hormone has a subtle influence on the sulfachloropyridazine sorption in pastoral soil. •Increased hormone concentrations decrease sulfachloropyridazine sorption in soils. -- Sorption affinity of SMO and SCP are strongly governed by multitude of factors, and variations in these factors can be significant when manure and fertilisers are added to soil

  4. Plant rhizosphere processes influencing the mobility of radionuclides in soils

    International Nuclear Information System (INIS)

    Cowan, C.E.; Cataldo, D.A.; McFadden, K.M.; Garland, T.R.; Wildung, R.E.

    1988-06-01

    Native vegetation associated with commercial low-level waste disposal sites has the potential for modifying the soil chemical environment over the long term and, consequently, affecting radionuclide mobility. These changes were assessed for coniferous and deciduous trees grown in lysimeter systems by examining their influence on soil solution chemistry using advanced analytical and geochemical modeling techniques. Our studies demonstrated the formation of highly mobile anionic radionuclide complexes with amino acids, peptides and organic acids originating from plant leaf litter and roots. The production of complexing agents was related to season and tree species, suggesting that vegetation management or exclusion may be appropriate after a site is closed

  5. Assessment of tillage systems in organic farming: influence of soil structure on microbial biomass. First results

    OpenAIRE

    Vian, Jean François; Peigné, Joséphine; Chaussod, Rémi; Roger-Estrade, Jean

    2007-01-01

    Soil tillage modifies environmental conditions of soil microorganisms and their ability to release nitrogen. We compare the influence of reduced tillage (RT) and mouldboard ploughing (MP) on the soil microbial functioning in organic farming. In order to connect soil structure generated by these tillage systems on the soil microbial biomass we adopt a particular sampling scheme based on the morphological characterisation of the soil structure by the description of the soil profile. This method...

  6. Influence of long-term fertilization on soil physicochemical properties in a brown soil

    Science.gov (United States)

    Li, Dongdong; Luo, Peiyu; Han, Xiaori; Yang, Jinfeng

    2018-01-01

    This study aims to explore the influence on soil physicochemical properties under a 38-y long-term fertilization in a brown soil. Soil samples (0-20 cm)were taken from the six treatments of the long-term fertilization trial in October 2016:no fertilizer (CK), N1(mineral nitrogen fertilizer), N1P (mineral nitrogen and phosphate fertilizer), N1PK (mineral nitrogen, phosphate and potassic fertilizer), pig manure (M2), M2N1P (pig manure, mineral nitrogen and phosphate fertilizer).The results showed thatthe long-term application of chemical fertilizers reduced soil pH value, while the application of organic fertilizers increased pH value. Fertilization significantly increased the content of AHN, TN and SOM. Compared with the CK treatment and chemical fertilizer treatments, organic fertilizer treatments significantly increased the content of AP and TP. The content of AK and TK were no significant difference in different treatment.

  7. Ecological factors governing the distribution of soil microfungi in some forest soils of Pachmarhi Hills, India

    Directory of Open Access Journals (Sweden)

    Shashi Chauhan

    2014-01-01

    Full Text Available An ecological study of the microfungi occurring in the various forest soils of Pachmarhi Hills, India has been carried-out by the soil plate technique. Soil samples from 5 different forest communities viz., moist deciduous forest dominated by tree ferns, Diospyros forest, Terminalia forest, Shorea forest and scrub forest dominated by Acacia and Dalbergia sp. were collected during October, 1983. Some physico-chemical characteristics of the soil were analysed and their role in distribution of fungi in 5 soil types was studied and discussed. 43 fungal species were isolated, of which Asperigillus niger I and Penicillium janthinellum occurred in all the 5 soil types. Statistically, none of the edaphic factors showed positive significant correlation with the number of fungi.

  8. Metal concentrations in aquatic macrophytes as influenced by soil and acidification

    Science.gov (United States)

    Sparling, D.W.; Lowe, T.P.

    1998-01-01

    Bioavailability of metals to aquatic plants is dependent on many factors including ambient metal concentration, pH of soil or water, concentration of ligands, competition with other metals for binding sites, and mode of exposure. Plants may be exposed to metals through water, air, or soil, depending on growth form. This paper examines the influence of soil type under two regimens of water acidification on metal uptake by four species of aquatic macrophytes: smartweed (Polygonum sagittatum), burreed (Sparganium americanum), pondweed (Potamogeton diversifolius), and bladderwort (Utricularia vulgaris) in constructed, experimentally acidified wetlands. Soil types consisted of a comparatively high-metal clay or a lower-metal sandy loam. Each pond was either acidified to pH ca. 4.85.3 or allowed to remain circumneutral. Metal concentrations tended to be higher in the submerged bladderwort and pondweed than in the emergent burreed and smartweed. Soils were important to plant metal concentrations in all species, but especially in the emergents. Acidification influenced plant concentrations of some metals and was especially important in the submerged pondweed. Bioaccumulation of metals occurred for Mn, B, Sr, Ba, and Zn, compared to soil concentrations.

  9. Influence of soil-structure interaction on floor response spectra

    International Nuclear Information System (INIS)

    Costantino, C.J.; Miller, C.A.; Curreri, J.R.

    1985-01-01

    A study was undertaken to investigate the influence of soil-structure interaction on floor response spectra developed in typical nuclear power plant structures. A horizontal earthquake time history, whose spectra envelops the Reg. Guide 1.60 criteria and is scaled to a 1 g peak acceleration, was used as input to structural models. Two different structural stick models were used, representing typical BWR and PWR facilities. By varying the structural and soil stiffness parameters, a wide range of system behaviors were investigated. Floor response spectra, required to assess equipment qualification, were of primary interest. It was found from a variation of parameter study that the interaction soil parameters, particularly radiation damping, greatly affect the nature of the calculated responses. (orig.)

  10. Digestate influence after biogas production on soil parameters

    Energy Technology Data Exchange (ETDEWEB)

    Igaz, D.; Horak, J.; Kondrlova, E.; Cimo, J. [Department of Biomereorology and Hydrology, Slovak University of Agriculture in Nitra, Nirra (Slovakia)

    2011-07-01

    Energy demands of society pun pressure on the use of alternative ways of getting the energy. From this point of view, the controlled anaerobic fermentation seems to be the perspective biotechnology: The final product of this process is an energy valuable raw - biogas and bio sludge. There was experimentally tested an influence of bio sludge on hydrophysical characteristics at the field condition of site Barca (Slovak Republic) with clav-loam soil. Based on the obtained results from three-year field experiment can be concluded that the application of the bio sludge on the soil does not contribute to the deterioration of soil hydrophysical properties. There was observed a positive effect on these properties, with observed increase of average value of capillary suction capacity, field capacity, porosity, non-capillary porosity and hydraulic conductivity. There was also observed decrease of average values of ρ{sub s} and ρ{sub d}. (author)

  11. Influence of soil-structure interaction on floor response spectra

    International Nuclear Information System (INIS)

    Costantino, C.J.; Miller, C.A.; Curreri, J.R.

    1985-01-01

    A study was undertaken to investigate the influence of soil-structure interaction on floor response spectra developed in typical nuclear power plant structures. A horizontal earthquake time history, whose spectra envelops the Regulatory Guide 1.60 criteria and is scaled to a log peak acceleration, was used as input to structural models. Two different structural stick models were used, representing typical BWR and PWR facilities. By varying the structural and soil stiffness parameters, a wide range of system behaviors were investigated. Floor response spectra, required to assess equipment qualification, were of primary interest. It was found from a variation of parameter study that the interaction soil parameters, particularly radiation damping, greatly affect the nature of the calculated responses. 2 refs., 2 figs., 2 tabs

  12. Influence of earthworms on the sulfur turnover in the soil.

    Science.gov (United States)

    Grethe, S; Schrader, S; Giesemann, A; Larink, O; Weigel, H J

    1996-08-01

    Abstract The effects of earthworm activity on the concentration and isotopic composition of total sulfur in soils was investigated using batch experiments. Two ecologically different lumbricid species, the anecic Lumbricus terrestris and the endogeic Aporrectodea caliginosa, were used. The earthworms were fed birch leaves, beech leaves, cattle manure or mixed plant litter. All food sources differed isotopically (δ(34)S) from the soil (Parabraunerde). As a reference, one experiment was carried out without additional food. The experimental results show, that both earthworm species influence the total S-content and the δ(34)S-values in the soil by digestion of the different food sources. The differences in the total S-content of the earthworm tissues and in the S-isotopic composition of the casts can be attributed to the ecological differences between the earthworm species.

  13. Factors influencing job satisfaction and organizational commitment.

    Science.gov (United States)

    Watson, Liana M

    2008-01-01

    To assess the relationship between intrinsic and extrinsic motivational factors influencing job satisfaction and the perspective of frontline medical imaging staff in acute care health care facilities in the United States. The sample consisted of 359 registered radiologic technologists who were working as staff technologists in acute care health care facilities in the United States. The results of the study suggest that satisfaction with intrinsic and extrinsic motivators influences overall satisfaction with the work environment and job and commitment to the employer.

  14. The Influence of Soil Moisture and Wind on Rainfall Distribution and Intensity in Florida

    Science.gov (United States)

    Baker, R. David; Lynn, Barry H.; Boone, Aaron; Tao, Wei-Kuo

    1998-01-01

    Land surface processes play a key role in water and energy budgets of the hydrological cycle. For example, the distribution of soil moisture will affect sensible and latent heat fluxes, which in turn may dramatically influence the location and intensity of precipitation. However, mean wind conditions also strongly influence the distribution of precipitation. The relative importance of soil moisture and wind on rainfall location and intensity remains uncertain. Here, we examine the influence of soil moisture distribution and wind distribution on precipitation in the Florida peninsula using the 3-D Goddard Cumulus Ensemble (GCE) cloud model Coupled with the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model. This study utilizes data collected on 27 July 1991 in central Florida during the Convection and Precipitation Electrification Experiment (CaPE). The idealized numerical experiments consider a block of land (the Florida peninsula) bordered on the east and on the west by ocean. The initial soil moisture distribution is derived from an offline PLACE simulation, and the initial environmental wind profile is determined from the CaPE sounding network. Using the factor separation technique, the precise contribution of soil moisture and wind to rainfall distribution and intensity is determined.

  15. The Influence of Heating Mains on Yeast Communities in Urban Soils

    Science.gov (United States)

    Tepeeva, A. N.; Glushakova, A. M.; Kachalkin, A. V.

    2018-04-01

    The number and species diversity of yeasts in urban soils (urbanozems) affected by heating mains and in epiphytic yeast complexes of grasses growing above them were studied. The number of yeasts in the soil reached 103-104 CFU/g; on the plants, 107 CFU/g. Significant (by an order of magnitude) increase in the total number of soil yeasts in the zone of heating mains in comparison with the surrounding soil was found in winter period. Overall, 25 species of yeasts were isolated in our study. Yeast community of studied urbanozems was dominated by the Candida sake, an eurybiont of the temperate zone and other natural ecotopes with relatively low temperatures, but its share was minimal in the zone of heating mains. In general, the structure of soil and epiphytic yeast complexes in the zones of heating mains differed from that in the surrounding area by higher species diversity and a lower share of pigmented species among the epiphytic yeasts. The study demonstrated that the number and species structure of soil yeast communities in urban soils change significantly under the influence of the temperature factor and acquire a mosaic distribution pattern.

  16. Overview of factors influencing the secondary market

    International Nuclear Information System (INIS)

    Bleistine, P.A.

    1982-01-01

    The major factor influencing secondary trading for the last few years has been the large contractural commitments built up by consumers for reactor programs which have proven to be unrealistic. The situation has intensified as a result of utilities needing to generate capital through inventory liquidation or reductions. The flexibilities in most contracts are inadequate to match the types of external and/or internal factors faced by the industry. This situation also suggests the need for secondary markets to help the industry adjust to unforeseen difficulties. They are very active markets at this time, but their influence in relation to the long-term method of doing business should not be exaggerated

  17. Transfer factors of Polonium from soil to parsley and mint

    International Nuclear Information System (INIS)

    Al-Masri, M.S.; Al-Hamwi, A.; Eadan, Z.; Amin, Y.

    2010-01-01

    Transfer factors of 210 Po from soil to parsley and mint have been determined. Artificial polonium isotope ( 208 Po) was used as a tracer to determine transfer factor of Po from soil to plant in pot experiments. Two plant growing systems were used for this study namely, an outdoor system and a sheltered system by a polyethylene tent. 208 Po and 210 Po were determined in soil and different parts of the studied plants (stem and leaf), using alpha spectroscopy. The results have shown that there was a clear uptake of 208 Po by roots to leaves and stems of both plants. Higher values of transfer factors using the 210 Po activity concentrations than the 208 Po activity concentration were observed. Transfer factors of 210 Po from soil to parsley varied between 20 x 10 -2 and 50 x 10 -2 and 22 x 10 -3 and 67 x 10 -3 in mint, while 208 Po transfer factors varied between 4 x 10 -2 and 12 x 10 -2 for parsley and 10 x 10 -2 and 22 x 10 -2 in mint. Transfer factors of Po were higher in those plants grown in the sheltered system than in the open system; about 75% of Po was transferred from atmosphere to parsley parts using the two systems. Ratios of transferred Po from soil to mint stem and leaf in the sheltered system were higher by 2 times from those in the open system.

  18. Influence of indian mustard (Brassica juncea) on rhizosphere soil solution chemistry in long-term contaminated soils: a rhizobox study.

    Science.gov (United States)

    Kim, Kwon-Rae; Owens, Gary; Kwon, Soon-lk

    2010-01-01

    This study investigated the influence of Indian mustard (Brassica juncea) root exudation on soil solution properties (pH, dissolved organic carbon (DOC), metal solubility) in the rhizosphere using a rhizobox. Measurement was conducted following the cultivation of Indian mustard in the rhizobox filled four different types of heavy metal contaminated soils (two alkaline soils and two acidic soils). The growth of Indian mustard resulted in a significant increase (by 0.6 pH units) in rhizosphere soil solution pH of acidic soils and only a slight increase (soil solution varied considerably amongst different soils, resulting in significant changes to soil solution metals in the rhizosphere. For example, the soil solution Cd, Cu, Pb, and Zn concentrations increased in the rhizosphere of alkaline soils compared to bulk soil following plant cultivation. In contrast, the soluble concentrations of Cd, Pb, and Zn in acidic soils decreased in rhizosphere soil when compared to bulk soils. Besides the influence of pH and DOC on metal solubility, the increase of heavy metal concentration having high stability constant such as Cu and Pb resulted in a release of Cd and Zn from solid phase to liquid phase.

  19. INFLUENCE FACTORS FOR LEASING MARKET CONTRACTS

    Directory of Open Access Journals (Sweden)

    Oana BĂRBULESCU

    2016-11-01

    Full Text Available This paper aims to investigate the relationship between leasing contracts and some factors that influence the value of these contracts. In order to do this, we have decided on some quantitative marketing research by appealing to statistics for accomplishing the objectives that we have set: to find a correlation between the turnover percentage assigned to leasing expenses and several influence factors. This study indicated that the more contracts are signed by a firm, the more likely is to assign a bigger fraction of the income to each new leasing contract. The study confirmed that bigger companies are relying more on leasing as a way of financing than small companies. This study also discovered that companies with more employees are using larger contracts in order to sustain their activity. The findings are expected to contribute to adjusting the offers by the leasing companies, taking into consideration these factors and to using these factors in order to better predict the market evolution.

  20. Factors Influencing Medical Students' Choice of Specialty

    OpenAIRE

    Chang, Pei-Yeh; Hung, Chih-Young; Wang, Kuei-lng; Huang, Yuan-Huei; Chang, King-Jen

    2006-01-01

    Medical school graduates are the source of a country's physicians. Determining how the graduates of these schools select their areas of specialization is the key to achieving a balanced distribution of doctors among all specialties. The purposes of this study were to determine the factors that influence medical students' choice of medical specialty, and to derive the relative weight of each factor. Methods: We constructed a two-tiered analytic hierarchy process (AHP) model which was repres...

  1. The influence of soil type at Cs-137-spreading in soil depth

    International Nuclear Information System (INIS)

    Tyrpanova, Kh.; Jordanova, I.

    1995-01-01

    The distribution of Cs-137 in soil depth up to 15 cm was examined for four types of soil - leached black earth, calcareous black earth, brown forest soil and slightly leached humus-calcareous soil. The behaviour of Cs-137 before and after Chernobyl accident depending on soil type was determined using Cs-134. Accounting for halftime effect of Cs-134 it was possible to distinguish the penetration of the Chernobyl Cs-137 from that of the older one. The same degree of penetration has been achieved: for 30 years for the old Cs-137 and only for a year for the Chernobyl one probably due to its modification. The most expressed tendency to penetrate in depth has been observed at the calcareous black earth (from Kozloduy region, with highest pH value and basis content), the least - at the brown forest soil (from Smolyan region, lowest pH value and basis content). The mineral composition and organic matter content influence the penetration process. The humus matter absorbs Cs-137. Thus it is accessible to the plants, but its penetration is limited to 2.5 cm. 9 refs., 2 tabs. (author)

  2. Long-term influence of tillage and fertilization on net carbon dioxide exchange rate on two soils with different textures.

    Science.gov (United States)

    Feiziene, Dalia; Feiza, Virginijus; Slepetiene, Alvyra; Liaudanskiene, Inga; Kadziene, Grazina; Deveikyte, Irena; Vaideliene, Asta

    2011-01-01

    The importance of agricultural practices to greenhouse gas mitigation is examined worldwide. However, there is no consensus on soil organic carbon (SOC) content and CO emissions as affected by soil management practices and their relationships with soil texture. No-till (NT) agriculture often results in soil C gain, though, not always. Soil net CO exchange rate (NCER) and environmental factors (SOC, soil temperature [T], and water content [W]), as affected by soil type (loam and sandy loam), tillage (conventional, reduced, and NT), and fertilization, were quantified in long-term field experiments in Lithuania. Soil tillage and fertilization affected total CO flux (heterotrophic and autotrophic) through effect on soil SOC sequestration, water, and temperature regime. After 11 yr of different tillage and fertilization management, SOC content was 23% more in loam than in sandy loam. Long-term NT contributed to 7 to 27% more SOC sequestration on loam and to 29 to 33% more on sandy loam compared with reduced tillage (RT) or conventional tillage (CT). Soil water content in loam was 7% more than in sandy loam. Soil gravimetric water content, averaged across measurement dates and fertilization treatments, was significantly less in NT than CT and RT in both soils. Soil organic carbon content and water storage capacity of the loam and sandy loam soils exerted different influences on NCER. The NCER from the sandy loam soil was 13% greater than that from the loam. In addition, NCER was 4 to 9% less with NT than with CT and RT systems on both loam and sandy loam soils. Application of mineral NPK fertilizers promoted significantly greater NCER from loam but suppressed NCER by 15% from sandy loam. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. Soil and vegetation influence in plants natural radionuclides uptake at a uranium mining site

    Science.gov (United States)

    Charro, E.; Moyano, A.

    2017-12-01

    The main objective of this work is to investigate the uptake of several radionuclides by the vegetation characteristic of a dehesa ecosystem in uranium mining-impacted soils in Central-West of Spain. The activity concentration for 238U, 226Ra, 210Pb, 232Th, and 224Ra was measured in soil and vegetation samples using a Canberra n-type HPGe gamma-ray spectrometer. Transfer factors of natural radionuclides in different tissues (leaves, branches, twigs, and others) of native plants were evaluated. From these data, the influence of the mine, the physicochemical parameters of the soils and the type of vegetation were analyzed in order to explain the accumulation of radionuclides in the vegetation. A preferential uptake of 210Pb and 226Ra by plants, particularly by trees of the Quercus species (Quercus pyrenaica and Quercus ilex rotundifolia), has been observed, being the transfer factors for 226Ra and 210Pb in these tree species higher than those for other plants (like Pinus pinaster, Rubur ulmifolius and Populus sp.). The analysis of radionuclide contents and transfer factors in the vegetation showed no evidence of influence of the radionuclide concentration in soils, although it could be explained in terms of the type of plants and, in particular, of the tree's species, with special attention to the tree's rate of growth, being higher in slow growing species.

  4. A factor analysis to detect factors influencing building national brand

    Directory of Open Access Journals (Sweden)

    Naser Azad

    Full Text Available Developing a national brand is one of the most important issues for development of a brand. In this study, we present factor analysis to detect the most important factors in building a national brand. The proposed study uses factor analysis to extract the most influencing factors and the sample size has been chosen from two major auto makers in Iran called Iran Khodro and Saipa. The questionnaire was designed in Likert scale and distributed among 235 experts. Cronbach alpha is calculated as 84%, which is well above the minimum desirable limit of 0.70. The implementation of factor analysis provides six factors including “cultural image of customers”, “exciting characteristics”, “competitive pricing strategies”, “perception image” and “previous perceptions”.

  5. Factors Influencing Donor Partnership Effectiveness | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2010-11-03

    Nov 3, 2010 ... A two-dimensional tool probing eight factors that influence partnership performance was developed, and used in conjunction with a Partnering Process Model, to guide the preparation of the case studies. The incorporation of the temporality dimension is quite novel and adds to the understanding and ...

  6. Factors influencing woodlands of southwestern North Dakota

    Science.gov (United States)

    Michele M. Girard; Harold Goetz; Ardell J. Bjugstad

    1987-01-01

    Literature pertaining to woodlands of southwestern North Dakota is reviewed. Woodland species composition and distribution, and factors influencing woodland ecosystems such as climate, logging, fire, and grazing are described. Potential management and improvement techniques using vegetation and livestock manipulation have been suggested.

  7. Factors influencing HIV seroprevalence rate among pregnant ...

    African Journals Online (AJOL)

    Human immune deficiency virus (HIV) seroprevalence among pregnant women in Calabar was studied. The aims were to establish HIV seroprevalence rate and to identify factors which influence this rate in our pregnant women. HIV seroprevalence rate of 2.7% among antenatal women in Calabar was recorded with a ...

  8. Factors influencing insulin secretion from encapsulated islets

    NARCIS (Netherlands)

    de Haan, BJ; Faas, MM; de Vos, P

    2003-01-01

    Adequate regulation of glucose levels by a microencapsulated pancreatic islet graft requires a minute-to-minute regulation of blood glucose. To design such a transplant, it is mandatory to have sufficient insight in factors influencing the kinetics of insulin secretion by encapsulated islets. The

  9. Socio-Economic Factors Influencing Entrepreneurship Among ...

    African Journals Online (AJOL)

    Socio-Economic Factors Influencing Entrepreneurship Among Women In Fishing Communities In Ondo State, Nigeria. ... The study found that overall entrepreneurial rating of the study group is low, essential input can not be easily gotten in the area, the respondents has large household size thereby had a large dependents ...

  10. Factors Influencing Information and Communication Technology ...

    African Journals Online (AJOL)

    Information and communication technology (ICT) is a veritable tool for sustainable agricultural development in Nigeria. This paper analyzed the factors that influenced ICT use by women research scientists in the Universities of Agriculture in Nigeria. Simple random sampling technique was used to select 40 respondents per ...

  11. Factors Influencing Examination Malpractice in Secondary Schools ...

    African Journals Online (AJOL)

    The main purpose of this study was to investigate factors influencing examination malpractice in some selected secondary schools in Cross River State, Nigeria. A sample of one thousand two hundred (1200) students were selected across the three educational zones of Ogoja, Ikom and Calabar using stratified, random ...

  12. Factors influencing laser cutting of wood

    Science.gov (United States)

    V.G. Barnekov; C.W. McMillin; H.A. Huber

    1986-01-01

    Factors influencing the ability of lasers to cut wood may be generally classified into these three areas: 1) characteristics of the laser beam; 2) equipment and processing variables; and 3) properties of the workpiece. Effects of beam power, mode, polarization, and stability are discussed as are aspects of optics, location of focal point, feed speed, gas-jet assist...

  13. Factors that influence advertising design ideation | Usman ...

    African Journals Online (AJOL)

    Factors that influence advertising design ideation. ... PROMOTING ACCESS TO AFRICAN RESEARCH ... inevitably, more than ever before, on advertisement to take products to the doorsteps of potential consumers. Consequently, local and global corporations employ all manner of advertising media to achieve their end.

  14. Factors Influencing Smallholder Farmers Participation in IFAD ...

    African Journals Online (AJOL)

    USER

    2015-02-02

    Feb 2, 2015 ... This study assessed Factors Influencing smallholder farmers' ... percent of the population engaged in agricultural activities as a career and ... that the major source of income of the poor is agriculture and ... shown that farmers have different reasons for participation in agricultural ... 30 Dan gamau 534. 30.

  15. Exploring Factors That Influence Quality Literature Circles

    Science.gov (United States)

    Young, Chase; Mohr, Kathleen A. J.

    2018-01-01

    Research indicates that literature circles are an authentic means for literacy development that students typically enjoy. To better understand the potential value and to add to the research base regarding literature circles, this study, involving 17 fourth graders, explores factors that may influence the quality of literature discussions,…

  16. Social Factors Influencing Child Health in Ghana.

    Directory of Open Access Journals (Sweden)

    Emmanuel Quansah

    Full Text Available Social factors have profound effects on health. Children are especially vulnerable to social influences, particularly in their early years. Adverse social exposures in childhood can lead to chronic disorders later in life. Here, we sought to identify and evaluate the impact of social factors on child health in Ghana. As Ghana is unlikely to achieve the Millennium Development Goals' target of reducing child mortality by two-thirds between 1990 and 2015, we deemed it necessary to identify social determinants that might have contributed to the non-realisation of this goal.ScienceDirect, PubMed, MEDLINE via EBSCO and Google Scholar were searched for published articles reporting on the influence of social factors on child health in Ghana. After screening the 98 articles identified, 34 of them that met our inclusion criteria were selected for qualitative review.Major social factors influencing child health in the country include maternal education, rural-urban disparities (place of residence, family income (wealth/poverty and high dependency (multiparousity. These factors are associated with child mortality, nutritional status of children, completion of immunisation programmes, health-seeking behaviour and hygiene practices.Several social factors influence child health outcomes in Ghana. Developing more effective responses to these social determinants would require sustainable efforts from all stakeholders including the Government, healthcare providers and families. We recommend the development of interventions that would support families through direct social support initiatives aimed at alleviating poverty and inequality, and indirect approaches targeted at eliminating the dependence of poor health outcomes on social factors. Importantly, the expansion of quality free education interventions to improve would-be-mother's health knowledge is emphasised.

  17. Soil geochemical factors regulate Cd accumulation by metal hyperaccumulating Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey in field-contaminated soils.

    Science.gov (United States)

    Rosenfeld, Carla E; Chaney, Rufus L; Martínez, Carmen E

    2018-03-01

    Cadmium contamination in soil is a substantial global problem, and of significant concern due to high food-chain transfer. Cadmium hyperaccumulators are of particular interest because of their ability to tolerate and take up significant amounts of heavy metal pollution from soils. One particular plant, Noccaea caerulescens (formerly, Thlaspi caerulescens), has been extensively studied in terms of its capacity to accumulate heavy metals (specifically Zn and Cd), though these studies have primarily utilized hydroponic and metal-spiked model soil systems. We studied Cd and nutrient uptake by two N. caerulescens ecotypes, Prayon (Zn-only hyperaccumulator) and Ganges (Zn- and Cd-hyperaccumulator) in four long-term field-contaminated soils. Our data suggest that individual soil properties such as total soil Cd, Zn:Cd molar ratio, or soil pH do not accurately predict Cd uptake by hyperaccumulating plants. Additionally, total Cd uptake by the hyperaccumulating Ganges ecotype was substantially less than its physiological capacity, which is likely due to Cd-containing solid phases (primarily iron oxides) and pH that play an important role in regulating and limiting Cd solubility. Increased P accumulation in the Ganges leaves, and greater plant Fe accumulation from Cd-containing soils suggests that rhizosphere alterations via proton, and potentially organic acid, secretion may also play a role in nutrient and Cd acquisition by the plant roots. The current study highlights the role that soil geochemical factors play in influencing Cd uptake by hyperaccumulating plants. While these plants may have high physiological potential to accumulate metals from contaminated soils, individual soil geochemical factors and the plant-soil interactions in that soil will dictate the actual amount of phytoextractable metal. This underlines the need for site-specific understanding of metal-containing solid phases and geochemical properties of soils before undertaking phytoextraction efforts

  18. The influence of wildfire severity on soil char composition and nitrogen dynamics

    Science.gov (United States)

    Rhoades, Charles; Fegel, Timothy; Chow, Alex; Tsai, Kuo-Pei; Norman, John, III; Kelly, Eugene

    2017-04-01

    Forest fires cause lasting ecological changes and alter the biogeochemical processes that control stream water quality. Decreased plant nutrient uptake is the mechanism often held responsible for lasting post-fire shifts in nutrient supply and demand, though other upland and in-stream factors also likely contribute to elevated stream nutrient losses. Soil heating, for example, creates pyrogenic carbon (C) and char layers that influence C and nitrogen (N) cycling. Char layer composition and persistence vary across burned landscapes and are influenced first by fire behavior through the temperature and duration of combustion and then by post-fire erosion. To evaluate the link between soil char and stream C and N export we studied areas burned by the 2002 Hayman Fire, the largest wildfire in Colorado, USA history. We compared soil C and N pools and processes across ecotones that included 1) unburned forests, 2) areas with moderate and 3) high wildfire severity. We analyzed 1-2 cm thick charred organic layers that remain visible 15 years after the fire, underlying mineral soils, and soluble leachate from both layers. Unburned soils released more dissolved organic C and N (DOC and DON) from organic and mineral soil layers than burned soils. The composition of DOC leachate characterized by UV-fluorescence, emission-excitation matrices (EEMs) and Fluorescence Regional Integration (FRI) found similarity between burned and unburned soils, underscoring a common organic matter source. Humic and fulvic acid-like fractions, contained in regions V and III of the FRI model, comprised the majority of the fluorescing DOM in both unburned and char layers. Similarity between two EEMs indices (Fluorescence and Freshness), further denote that unburned soils and char layers originate from the same source and are consistent with visual evidence char layers contain significant amounts of unaltered OM. However, the EEMs humification index (HIX) and compositional analysis with pyrolysis GCMS

  19. Factors that influence women's dispositions toward science

    Science.gov (United States)

    Atria, Catherine Graczyk

    Females have been underrepresented in the study of science and science careers for decades although advancements have been made in closing this gender gap, the gap persists particularly in the physical sciences. Variables which influence a woman's desire to pursue and maintain a science course of study and career must be discovered. The United States lags behind other industrialized countries in the fields of science, math, and engineering. Females comprise an estimated half of the population; their potential contributions cannot be ignored or overlooked. This retrospective research study explores the personal experiences of ten women enrolled in science majors, with science related career plans. The goal of this study is to describe the factors that influence the participants' interest in science. The findings, the effect of science coursework, science teachers' personality and manner, other influential educational personnel, role models and mentors, external influences exclusive of school, parental influence, locus of control and positive attitudes toward science confirm what other researchers have found.

  20. Factors influencing in situ gamma-ray measurements

    Science.gov (United States)

    Loonstra, E. H.; van Egmond, F. M.

    2009-04-01

    Introduction In situ passive gamma-ray sensors are very well suitable for mapping physical soil properties. In order to make a qualitative sound soil map, high quality input parameters for calibration are required. This paper will focus on the factors that affect the output of in situ passive gamma-ray sensors, the primary source, soil, not taken into account. Factors The gamma-ray spectrum contains information of naturally occurring nuclides 40K, 238U and 232Th and man-made nuclides like 137Cs, as well as the total count rate. Factors that influence the concentration of these nuclides and the count rate can be classified in 3 categories. These are sensor design, environmental conditions and operational circumstances. Sensor design The main elements of an in situ gamma-ray sensor that influence the outcome and quality of the output are the crystal and the spectrum analysis method. Material and size of the crystal determine the energy resolution. Though widely used, NaI crystals are not the most efficient capturer of gamma radiation. Alternatives are BGO and CsI. BGO has a low peak resolution, which prohibits use in cases where man-made nuclides are subject of interest. The material is expensive and prone to temperature instability. CsI is robust compared to NaI and BGO. The density of CsI is higher than NaI, yielding better efficiency, especially for smaller crystal sizes. More volume results in higher energy efficiency. The reduction of the measured spectral information into concentration of radionuclides is mostly done using the Windows analysis method. In Windows, the activities of the nuclides are found by summing the intensities of the spectrum found in a certain interval surrounding a peak. A major flaw of the Windows method is the limited amount of spectral information that is incorporated into the analysis. Another weakness is the inherent use of ‘stripping factors' to account for contributions of radiation from nuclide A into the peak of nuclide B. This

  1. Influence of Organic Manure on Organic Phosphorus Fraction in Soils

    Institute of Scientific and Technical Information of China (English)

    ZHANGYONG-SONG; NIWU-ZHONG; 等

    1993-01-01

    The transformation of organic P(Po) from organic manures in two types of soils (ultisol and entisol) and the influences of external addition of organic substance or inorganic P(Pi) on Po under the condition of the 60% maximum water capacity were investigated.The results obtained from Po fractionation experiments indicated that all the Po fractions except for the highly resistant Po fraction decreased during incubation.Application of pig feces and cow feces could largely increase each fraction of Po in the soils.Immediately after application of organic manure into the soils a large part of labile and moderately labile Po from organic manure was transferred into moderately resistant Po,which might be due to the fact that Ca-or Mg-inositol P was precipitated into Fe-inositol P.However,the availability of Po from organic manure in the soils would increase again after incubation because of the transformation of moderately labile and resistant Po fractions into labile Po fractions.Addition of cellulose or Pi into the soils showed a good effect on increasing all the Po fractions except for the highly resistant Po,and this effect was much more pronounced when cellulose was applied in combination with Pi.Therefore,in view of the effect of organic manure on improving P nutrition to plant,attention should be paid to both the Po and the organic substances from organic manure,It is suggested that application of Pi fertilizer combined with organic manure may be referred to as an effective means of protecting Pi from chemical fixation in soil.

  2. Theoretical difference between impact factor and influence factor

    Directory of Open Access Journals (Sweden)

    Đilda Pečarić

    2010-06-01

    Full Text Available Bibliometric constructions of "knowledge maps" and "cognitive structures of science" do not differentiate between impact and influence factors. The difference can be constructedaccording to different meaning and interpretation of the terms reference and citation. Reference is "acknowledgment which one author gives to another", whereas citation is "acknowledgment which one document receives from another". Development of Information Science according to period and subject area is analyzed on the corpus of citation literature retrieved from doctoral dissertations in Information Science from 1978 to 2007 at Croatian universities. The research aim is to indicate the difference between document impact factor and author's influence factor (i.e. reference ability to produce effects on actions, behavior, and opinions of authors of doctoral theses. The influence factor serves to distinguish the key role of cited authors in time and according to the duration of the influence (the average age for cited papers of dominant authors in different periods is between eight and ten years. The difference between linear and interactive communication seems vital for the interpretation of cited half-life, i.e. the attitude of one science community towards used information resources and cognitive heritage. The analyzed corpus of 22,210 citations can be divided into three communication phases according to influence factor criteria: in the phase of dialogue and interactive communication 25% of bibliographic units are cited in the first four years; in the second phase another 25% of units are cited from the fifth to the ninth year; after ten years, in the dominant linear communication phase, approximately 30% of units are cited.

  3. Soil-to-plant concentration factors for radiological assessments

    International Nuclear Information System (INIS)

    Ng, Y.C.; Thompson, S.E.; Colsher, C.S.

    1982-09-01

    This report presents the results of a literature review to derive soil-to-plant concentration factors to predict the concentration of a radionuclide in plants from that in soil. The concentration factor, B/sub v/ is defined as the ratio of the concentration of a nuclide in the edible plant part to that in dry soil. CR (the concentration ratio) is similarly defined to denote the concentration factor for dry feed consumed by livestock. B/sub v/ and CR values are used to assess the dose from radionuclides deposited onto soil and transferred into crop plants via roots. Approaches for deriving B/sub v/ and CR values are described, and values for food and feed are tabulated for individual elements. The sources of uncertainty are described, and the factors that contribute to the inherent variability of the B/sub v/ and CR values are discussed. Summary tables of elemental B/sub v/ and CR values and statistical parameters that characterize their distributions provide a basis for a systematic updating of many of the B/sub v/ values in Regulatory Guide 1.109. They also provide a basis for selecting B/sub v/ and CR values for other applications that involve the use of equilibrium models to predict the concentration of radionuclides in plants from that in soil

  4. Investigating important factors influencing purchasing from chains

    Directory of Open Access Journals (Sweden)

    Naser Azad

    2012-04-01

    Full Text Available In this paper, we survey important factors, influencing customers to buy more from one of well known food market operating in capital city of Iran named Shahrvand. The survey studies the effects of six factors including customer's perception, persuasive factors, brand, customers' expectations, product's characteristics and special features of store on attracting more customers. We have distributed questionnaire among 196 customers who regularly visit stores and analyzed details of the data. The results indicate that customers' perception is the most important item, which includes eight components. Years of experience is the most important item in our survey followed by impact of color and working hours. Diversity of services is another factor, which plays the most important role followed by quality of services. Next, fidelity and brand are other most important factors and the name of store and risk are in lower degree of importance.

  5. What Factors Influence Knowledge Sharing in Organizations?

    DEFF Research Database (Denmark)

    Razmerita, Liana; Kirchner, Kathrin; Nielsen, Pia

    2016-01-01

    factors drive employees’ participation and what factors hamper their participation in enterprise social media. Design/methodology/approach: Based on a literature review, a unified research model is derived integrating demographic, individual, organizational and technological factors that influence......Purpose: Enterprise social media platforms provide new ways of sharing knowledge and communicating within organizations to benefit from the social capital and valuable knowledge that employees have. Drawing on social dilemma and self-determination theory, the aim of the study is to understand what...... knowledge sharing framework helps to understand what factors impact engagement on social media. Furthermore the article suggests different types of interventions to overcome the social dilemma of knowledge sharing. Originality/value: The study contributes to an understanding of factors leading...

  6. Does relatedness of natives used for soil conditioning influence plant-soil feedback of exotics?

    Czech Academy of Sciences Publication Activity Database

    Dostál, Petr; Plačková, M.

    2011-01-01

    Roč. 13, č. 2 (2011), s. 331-340 ISSN 1387-3547 R&D Projects: GA AV ČR KJB600050713 Institutional research plan: CEZ:AV0Z60050516 Keywords : phylogenetic relatedness * plant invasions * soil microbiota Subject RIV: EF - Botanics Impact factor: 2.896, year: 2011

  7. Analysis on the influence of forest soil characteristics on radioactive Cs infiltration

    International Nuclear Information System (INIS)

    Mori, Yoshitomo; Yoneda, Minoru; Shimada, Yoko; Shimomura, Ryohei; Fukutani, Satoshi; Ikegami, Maiko

    2017-01-01

    Soil core (0-5 cm and 5-10 cm) was collected in 5 points with different vegetation in Fukushima Prefecture in order to explore the permeability, field capacity and voidage. Depth profiles of radioactive Cs, ignition loss and CEC (Cation Exchange Capacity) in the 5 forest soils were also investigated, using scraper plate (at 0.5 cm intervals for 0-5 cm and at 1.0 cm intervals for 5-10 cm). Depth profiles in soil layers were totally different between forests and did not show explicit correlation with field capacity, voidage or ignition loss. On the other hand, CEC correlated weakly and permeability did strongly with infiltration of radioactive Cs. Compartment modeling was conducted, so as to reproduce the monitored depth profile, taking ignition loss as a parameter, based on the experiment result that ignition loss had positive correlation with CEC, which might influence the adsorption process on radioactive Cs in soil layer. However, the ignition loss alone failed to fully reproduce the depth profile. Considering the present results as well as the fact that permeability might have explicit relation with infiltration of radioactive Cs, factors related with precipitation or water flow in early stage after the accident could influence the depth profile, before adsorbed with negative charge in soil particles. (author)

  8. Influence of the soil-atmosphere exchange on the hydric profile induced in soil-structure system

    Directory of Open Access Journals (Sweden)

    A. Al Qadad

    2012-06-01

    Full Text Available Soil-atmosphere exchange leads to a moisture change in the soil. This can cause major damage to engineering structures due to the soil expansion and shrinkage. The soil-atmosphere exchange is related to several parameters, in particular the soil characteristics and climate conditions. The presence of an engineering structure causes a variation of the hydraulic profile in the soil, which can lead to heterogeneous soil movement and consequently to structural damage. This paper presents a coupled numerical model based on the consideration of both water flow in unsaturated soils and soil-atmosphere exchange. After the validation of the model, the paper presents its use for the analysis of the influence of the presence of structures on moisture change induced under climatic conditions recorded in a semi-arid region. Analysis shows that the presence of the structure leads to important change in the moisture distribution, in particular in the vicinity of the structure.

  9. Influence of organizational factors on safety

    International Nuclear Information System (INIS)

    Haber, S.B.; Metlay, D.S.; Crouch, D.A.

    1990-01-01

    There is a need for a better understanding of exactly how organizational management factors at a nuclear power plant (NPP) affect plant safety performance, either directly or indirectly, and how these factors might be observed, measured, and evaluated. The purpose of this research project is to respond to that need by developing a general methodology for characterizing these organizational and management factors, systematically collecting information on their status and integrating that information into various types of evaluative activities. Research to date has included the development of the Nuclear Organization and Management Analysis Concept (NOMAC) of a NPP, the identification of key organizational and management factors, and the identification of the methods for systematically measuring and analyzing the influence of these factors on performance. Most recently, two field studies, one at a fossil fuel plant and the other at a NPP, were conducted using the developed methodology. Results are presented from both studies highlighting the acceptability, practicality, and usefulness of the methods used to assess the influence of various organizational and management factors including culture, communication, decision-making, standardization, and oversight. 6 refs., 3 figs., 1 tab

  10. Factors Influencing Colorectal Cancer Screening Participation

    Directory of Open Access Journals (Sweden)

    Antonio Z. Gimeno García

    2012-01-01

    Full Text Available Colorectal cancer (CRC is a major health problem worldwide. Although population-based CRC screening is strongly recommended in average-risk population, compliance rates are still far from the desirable rates. High levels of screening uptake are necessary for the success of any screening program. Therefore, the investigation of factors influencing participation is crucial prior to design and launches a population-based organized screening campaign. Several studies have identified screening behaviour factors related to potential participants, providers, or health care system. These influencing factors can also be classified in non-modifiable (i.e., demographic factors, education, health insurance, or income and modifiable factors (i.e., knowledge about CRC and screening, patient and provider attitudes or structural barriers for screening. Modifiable determinants are of great interest as they are plausible targets for interventions. Interventions at different levels (patient, providers or health care system have been tested across the studies with different results. This paper analyzes factors related to CRC screening behaviour and potential interventions designed to improve screening uptake.

  11. Influence of soil properties and soil leaching on the toxicity of ionic silver to plants.

    Science.gov (United States)

    Langdon, Kate A; McLaughlin, Mike J; Kirby, Jason K; Merrington, Graham

    2015-11-01

    Silver (Ag) has been shown to exhibit antimicrobial properties; as a result, it is being used increasingly in a wide range of consumer products. With these uses, the likelihood that Ag may enter the environment has increased, predominately via land application of biosolids or irrigation with treated wastewater effluent. The aim of the present study was to investigate the toxicity of Ag to 2 plant species: barley (Hordeum vulgare L. CV Triumph) and tomato (Lycopersicum esculentum) in a range of soils under both leached and unleached conditions. The concentrations that resulted in a 50% reduction of plant growth (EC50) were found to vary up to 20-fold across the soils, indicating a large influence of soil type on Ag toxicity. Overall, barley root elongation was found to be the least sensitive to added Ag, with EC50 values ranging from 51 mg/kg to 1030 mg/kg, whereas the tomato plant height showed higher sensitivity with EC50 values ranging from 46 mg/kg to 486 mg/kg. The effect of leaching was more evident in the barley toxicity results, where higher concentrations of Ag were required to induce toxicity. Variations in soil organic carbon and pH were found to be primarily responsible for mitigating Ag toxicity; therefore, these properties may be used in future risk assessments for Ag to predict toxicity in a wide range of soil types. © 2015 SETAC.

  12. Hot regions of labile and stable soil organic carbon in Germany - Spatial variability and driving factors

    Science.gov (United States)

    Vos, Cora; Jaconi, Angélica; Jacobs, Anna; Don, Axel

    2018-06-01

    Atmospheric carbon dioxide levels can be mitigated by sequestering carbon in the soil. Sequestration can be facilitated by agricultural management, but its influence is not the same on all soil carbon pools, as labile pools with a high turnover may be accumulated much faster but are also more vulnerable to losses. The aims of this study were to (1) assess how soil organic carbon (SOC) is distributed among SOC fractions on a national scale in Germany, (2) identify factors influencing this distribution and (3) identify regions with high vulnerability to SOC losses. The SOC content and proportion of two different SOC fractions were estimated for more than 2500 mineral topsoils (soil texture, bulk soil C / N ratio, total SOC content and pH. For some regions, the drivers were linked to the land-use history of the sites. Arable topsoils in central and southern Germany were found to contain the highest proportions and contents of stable SOC fractions, and therefore have the lowest vulnerability to SOC losses. North-western Germany contains an area of sandy soils with unusually high SOC contents and high proportions of light SOC fractions, which are commonly regarded as representing a labile carbon pool. This is true for the former peat soils in this area, which have already lost and are at high risk of losing high proportions of their SOC stocks. Those black sands can, however, also contain high amounts of stable SOC due to former heathland vegetation and need to be treated and discussed separately from non-black sand agricultural soils. Overall, it was estimated that, in large areas all over Germany, over 30 % of SOC is stored in easily mineralisable forms. Thus, SOC-conserving management of arable soils in these regions is of great importance.

  13. Influence of land improvement on soil oxidation. Inverkan av grundfoerbaettring paa markens syrehalt

    Energy Technology Data Exchange (ETDEWEB)

    Kowalik, P.J.

    1985-01-01

    The paper presents the theoretical analysis of influence of the land reclamation on soil oxidation. Examination was carried out on dependencies existing among soil moisture content, respiratory activity of the soil, absolute soil porosity, gas-filled soil porosity, coeffficient of oxygen diffusion in soil air and soil liquid, oxygen concentration in soil air and in soil water, oxygen diffusion flux, oxygen diffusion rate and the depth of zone of aeration in soil profile. Some remarks about the influence of soil oxidation on root growth and morphology of soil profile were presented too. Results of own empirical investigations and similar data from literature verify theoretical ideas pointed out in the paper. The methods and results of own measurements of ODR (oxygen diffusion rate) has been presented in detail. The research explains the relationship between soil moisture content and soil oxidation. As a result of the analysis there have been proposed such methods of land improvement that the water and oxygen demands of plant roots and microorganisms would be satisfying. The paper proposes a new method of account of the so-called anaerobic soil moisture content. This moisture should be the highest for irrigation practice and more or less lowest for drainage of soil water. Soil moisture a little lower than anarobic soil water content is enough for warranting the sufficient soil aeration during drainage and irrigation activity. With 82 refs.

  14. 3.4. Chemical additives and granulometric composition influence on soils armed by cement

    International Nuclear Information System (INIS)

    Saidov, D.Kh.

    2011-01-01

    Purpose of this work was to evaluate an influence of various chemical additives on soils armed by portland cement. Experimental research of kinetics of soil cements structure formation after adding the chemicals was carried out. According to the investigations it was determined that structure formation process of soil cements depended on granulometric composition of armed soil, cement quantity, type and quantity of chemical additives.

  15. Distribution and mobility of exogenous copper as influenced by aging and components interactions in three Chinese soils.

    Science.gov (United States)

    Shi, Hanzhi; Li, Qi; Chen, Wenli; Cai, Peng; Huang, Qiaoyun

    2018-04-01

    Copper contamination of soils is a global environmental problem. Soil components (organic matter, clay minerals, and microorganisms) and retention time can govern the adsorption, fixation, and distribution of copper. This study evaluated the interaction effects of soil components and aging on the distribution of exogenous copper. Three typical Chinese soils (Ultisol, Alfisol, and Histosol) were collected from Hunan, Henan, and Heilongjiang Provinces. Soils were incubated with rice straw (RS) and engineered bacteria (Pseudomonas putida X4/pIME) in the presence of exogenous copper for 12 months. Sequential extraction was employed to obtain the distribution of Cu species in soils, and the mobility factors of Cu were calculated. The relationships between soil properties and Cu fractions were analyzed with stepwise multiple linear regression. The results show that organic carbon plays a more important role in shaping the distribution of relatively mobile Cu, and iron oxides can be more critical in stabilizing Cu species in soils. Our results suggest that organic matter is the most important factor influencing copper partitioning in Ultisols, while iron oxides are more significant in Alfisols. The mobility of exogenous Cu in soils depends largely on organic carbon, amorphous Fe, and aging. The introduction of both rice straw and rice straw + engineered bacteria enhanced the stabilization of Cu in all the three soils during aging process. The introduction of bacteria could reduce copper mobility, which was indicated by the lowest mobility factors of Cu for the treatment with bacteria in Black, Red, and Cinnamon soils at the first 4, 8, and 8 months, respectively. Different measures should be taken into account regarding the content of organic matter and iron oxides depending on soil types for the risk assessment and remediation of Cu-contaminated soils.

  16. Plant rhizosphere processes influencing radionuclide mobility in soil

    International Nuclear Information System (INIS)

    Cataldo, D.A.; Cowan, C.E.; McFadden, K.M.; Garland, T.R.; Wildung, R.E.

    1987-10-01

    Native vegetation associated with commercial low-level waste disposal sites has the potential for modifying the soil chemical environment over the long term and, consequently, the mobility of radionuclides. These effects were assessed for coniferous and hardwood tree species by using plants grown in lysimeter systems and examining their influence on soil solution chemistry using advanced analytical and geochemical modeling techniques. The study demonstrated formation of highly mobile anionic radionuclide complexes with amino acids, peptides, and organic acids originating from plant leaf litter and roots. The production of complexing agents was related to season and tree species, suggesting that vegetation management and exclusion may be appropriate after a site is closed. This research provides a basis for focusing on key complexing agents in future studies to measure critical affinity constants and to incorporate this information into mathematical models describing biological effects on radionuclide mobility. 26 refs., 5 figs., 23 tabs

  17. Factors Influencing Tacit Knowledge in Construction

    Directory of Open Access Journals (Sweden)

    Jawahar Nesan

    2012-11-01

    Full Text Available Increased complexity of the construction business and consequentuse of new management concepts and technologies ledconstruction organisations to focus more on the transfer of explicitknowledge. However, it is the tacit knowledge that determinesthe construction companies’ competitiveness in a business thatis driven by turbulent market conditions and customers’ everincreasingdemands. This paper highlights the importance of tacitknowledge sharing in construction, explores the challenges andopportunities to efficiently share tacit knowledge, and based on theliterature review identifies some critical factors that influence tacitknowledge in construction. It is argued that employees’ knowledgesharing (learning behaviours are influenced by work practices thatare borne by respective organisational behaviours. Organisational,cultural, and project characteristics that facilitate knowledgesharing among construction employees are explored and thepractices that influence the construction employee behaviour insharing tacit knowledge are highlighted.

  18. Investigating different factors influencing on brand equity

    Directory of Open Access Journals (Sweden)

    Afsane Zamanimoghadam

    2014-07-01

    Full Text Available The purpose of this paper is to determine and prioritize factors influencing on brand equity in consumer’s point of view for a case study of Samsung appliance consumers in city of Tehran, Iran. The study investigates the effects of four factors in terms of the customer's perspective, price, advertisement, family and brand image, by dimensions of brand equity, perceived quality, brand awareness, brand association, brand loyalty, on brand equity. The research method is based on a descriptive-survey research. The questionnaire includes Samsung consumers in city of Tehran, Iran. To test the hypotheses, SPSS and LISREL software packages are used. For data analysis, descriptive statistics and inferential statistical tests including structural equation modeling and path analysis are used. The results of the survey have indicated that family and brand image influence positively on brand equity but the effects of advertisement and price on brand equity were not confirmed.

  19. FACTORS INFLUENCING THE MANAGEMENT OF ADHD

    OpenAIRE

    S ARMAN; M SOLTANI

    2003-01-01

    Introduction: Attention deficit hyperactivity disorder (ADHD)is the most common psychiatric disorder among school age children. It consists of hyperactivity, inattention and impulsive behavior. The onset of the disorder is before the age of 7 years and it happens at least in two situations. It causes significant impairment in social and academic functioning. A determination of factors that influences the therapeutic response in ADHD is the aim of this study. Methods: This study is design...

  20. Factors influencing laser cutting of wood

    Energy Technology Data Exchange (ETDEWEB)

    Barnekov, V. G.; McMillin, C. W.; Huber, H. A.

    1986-07-01

    Factors influencing the ability of lasers to cut wood may be generally classified into these three areas: 1) characteristics of the laser beam; 2) equipment and processing variables; and 3) properties of the work piece. Effects of beam power, mode, polarization, and stability are discussed as are aspects of optics, location of focal point, feed speed, gas-jet assist system and work piece thickness, density, and moisture content. (author)

  1. Psychological Factors Influencing Life Satisfaction of Undergraduates

    OpenAIRE

    Ajayi, Olubukola; Adewumi, Bukunmi

    2017-01-01

    This study was designed to assess the psychological factors influencing life satisfaction of undergraduates. The instruments used were Perceived Stress Scale (PSS), Wong and Law Emotional Intelligence Scale (WLEIS), Rosenberge Self-esteem Scale (RSS), and Satisfaction with Life Scale (SWLS). A total number of 190 participants were purposively selected across various faculties in Ekiti State University. Four hypotheses were tested using Independent t-test to find the effects of perceived stres...

  2. An approach for modeling the influence of wheel tractor loads and vibration frequencies on soil compaction

    Science.gov (United States)

    Verotti, M.; Servadio, P.; Belfiore, N. P.; Bergonzoli, S.

    2012-04-01

    Both soil compaction and ground vibration are forms of environmental degradation that may be understood in the context of the vehicle-soil interaction process considered (Hildebrand et al., 2008). The transit of tractors on agricultural soil is often the main cause of soil compaction increasing. As known, this can be a serious problems for tillage and sowing and therefore the influence of all the affecting factors have been extensively studied in the last decades in order to understand their impact on the biosystem. There are factors related to the climate, namely to the rainfalls and temperature, and many others. Hence, it is not simple to figure out a complete model for predicting an index of compaction, for a given situation. Soil compaction models are important tools for controlling soil compaction due to agricultural field traffic and they are potentially useful technique to provide information concerning correct soil management. By means of such models, strategies and recommendations for prevention of soil compaction may be developed and specific advice may be given to farmers and advisers. In order to predict field wheeled and tracked vehicle performance, some empirical methods, used for off-road vehicle, were applied by Servadio (2010) on agricultural soil. The empirical indexes included, besides the soil strength, the load carried by the tire or track, some technical characteristics of the tire or track of the vehicle (tire or track width, tire or track wheel diameter, unloaded tire section height, number of wheel station in one track, tire deflection, total length of the belt track, the track pitch) as well as the vehicle passes. They have been validated with the tests results of agricultural vehicles over a range of soil in central Italy. Among the parameters which affect soil compaction, the water content of the soil, the axle load and number of vehicle passes proved to be the most important ones. The present paper concerns mainly vehicle-soil

  3. Soil chemical factors and grassland species density in Emas National Park (central Brazil).

    Science.gov (United States)

    Amorim, P K; Batalha, M A

    2008-05-01

    Studies of grasslands on specific soil types suggest that different nutrients can limit biomass production and, hence, species composition and number. The Brazilian cerrado is the major savanna region in America and once covered about 2 million km(2), mainly in the Brazilian Central Plateau, under seasonal climate, with wet summer and dry winter. In view of the importance of soil chemical factors in the distribution of the vegetation forms within the Cerrado domain and which may influence the number of species, we analyzed some soil characteristics in three herbaceous vegetation forms -- hyperseasonal cerrado, seasonal cerrado, and wet grassland -- in Emas National Park, a core cerrado site, to investigate the relationship between number of species and soil characteristics. We collected vegetation and soil samples in these three vegetation forms and submitted the obtained data to multiple linear regression. We found out that aluminum and pH were the best predictors of species density, the former positively related to species density and the latter negatively related. Since the predictable variation in species density is important in determining areas of conservation, we can postulate that these two soil factors are indicators of high species density areas in tropical grasslands, which could be used in selecting priority sites for conservation.

  4. Sorption of samarium in soils: influence of soil properties and Sm concentration

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Guinart, Oriol; Salaberria, Aitor; Rigol, Anna; Vidal, Miquel [Analytical Chemistry department, Faculty of Chemistry, University of Barcelona, Marti i Franques 1-11, 08028, Barcelona (Spain)

    2014-07-01

    Due to the fact that barriers of Deep Geological Repositories (DGR) may lose efficiency before the radioisotopes present in the High Level Radioactive Waste (HLRW) completely decay, it is possible that, in the long-term, radioactive leachates may escape from the DGR and reach the soil and water compartments in the biosphere. Therefore, it is required to examine the interaction and mobility of radionuclides present in the HLRW, or their chemical analogues, to predict the impact of their eventual incorporation in the biosphere and to assess the derived risk. Although relevant data have been recently obtained for a few radionuclides in soils, there are still some important gaps for some radionuclides, such us for samarium (Sm). Sm is a lanthanide that, besides being considered as a natural analogue of actinides, may also be present in HLRW in the form of the radioactive isotope {sup 151}Sm. The main objective of this work was to obtain sorption data (K{sub d}) of {sup 151}Sm gathered from a set of soil samples physicochemical fully-characterized (pH, texture, cationic exchange capacity, soil solution cationic composition, organic matter, carbonate and metallic oxides content, etc.). Additionally, as an alternative for testing sorption capacity of radionuclides in soils is the use of the corresponding stable isotope or a chemical analogue, the influence of Sm concentration was also checked. To evaluate {sup 151}Sm sorption, batch assays were carried out for each soil sample, which consisted in a pre-equilibration step of 2 g of each soil with 50 ml of double deionised water, and a subsequent equilibration step with the same solution, but labelled with {sup 151}Sm. The activity of {sup 151}Sm in initial and final solutions was measured by liquid scintillation and K{sub d} ({sup 151}Sm) data were calculated. The reversibly sorbed fraction was estimated by the application of a single extraction test, with double deionised water, to soil residues coming from the previous

  5. Limiting Factors for Agricultural Production and Differentiation of Soil Management in Romania

    Science.gov (United States)

    Ioana Moraru, Paula; Rusu, Teodor; Bogdan, Ileana; Ioan Pop, Adrian; Pop, Horia

    2017-04-01

    Romania's land area is 23,839,100 ha; 0.16% of the world's surface. Worldwide, Romania is ranked #83 for areal extent, and it consitutes 4.81% of the Europe's surface (ranked #12). Romania has 14,856,800 ha of agricultural land which represents 62.3% of the total surface; 0.65 ha per capita. At the national level, 72.5% and 27.5% of soils in Romania can be broadly classed as very poor and good/very good, respectively, based on intrinsic soil characteristics, climate, topography, and ground water. Romania has a specific geographical situation, namely: i) Romanian territory is located in the southeast portion of Central Europe at the cross roads of several high and low pressure centers that form regularly at the borders. The influence of these air masses is altered by the presence in the central regions of the Carpathian mountain chain resulting in a diverse climate with average annual rain fall amounts between 350 to 1,400 mm and average annual temperatures between 2 and 11.5°C. ii) At the national level, almost all soils in the international classification system are present in Romania; each soil type having specific properties and characteristics. iii) On approximately 12.5 million ha (7.5 million ha arable), soil fertility is adversely affected by erosion, acidity, low humus content, extreme texture (clay, sand), excessive moisture, chemical pollution etc. These natural and anthropogenic factors dramatically influence agricultural production. Furthermore, soil, climate, topography, etc. vary widely not only across the country, but also on smaller scales, even across fields within the same farm. In Steppe zone limitative climatic factors, which require differentiation towards soil management use, include: long periods of drought, high temperatures, high frequency winds (wind erosion in area of sands), low relative air humidity, and harsh frosts during winter. Negative phenomena most commonly encountered in this area are salinization, excess water, temporary

  6. Transfer factors of polonium from soil to parsley and mint.

    Science.gov (United States)

    Al-Masri, M S; Al-Hamwi, A; Eadan, Z; Amin, Y

    2010-12-01

    Transfer factors of (210)Po from soil to parsley and mint have been determined. Artificial polonium isotope ((208)Po) was used as a tracer to determine transfer factor of Po from soil to plant in pot experiments. Two plant growing systems were used for this study namely, an outdoor system and a sheltered system by a polyethylene tent. (208)Po and (210)Po were determined in soil and different parts of the studied plants (stem and leaf), using alpha spectroscopy. The results have shown that there was a clear uptake of (208)Po by roots to leaves and stems of both plants. Higher values of transfer factors using the (210)Po activity concentrations than the (208)Po activity concentration were observed. Transfer factors of (210)Po from soil to parsley varied between 20 × 10⁻² and 50 × 10⁻² and 22 × 10⁻³ and 67 × 10⁻³ in mint, while (208)Po transfer factors varied between 4 × 10⁻² and 12 × 10⁻² for parsley and 10 × 10⁻² and 22 × 10⁻² in mint. Transfer factors of Po were higher in those plants grown in the sheltered system than in the open system; about 75% of Po was transferred from atmosphere to parsley parts using the two systems. Ratios of transferred Po from soil to mint stem and leaf in the sheltered system were higher by 2 times from those in the open system. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Transfer factors of Polonium from soil to parsley and mint

    Energy Technology Data Exchange (ETDEWEB)

    Al-Masri, M.S., E-mail: prscientific@aec.org.s [Department of Protection and Safety, Atomic Energy Commission of Syria, Damascus, P.O. Box 6091 (Syrian Arab Republic); Al-Hamwi, A. [Department of Protection and Safety, Atomic Energy Commission of Syria, Damascus, P.O. Box 6091 (Syrian Arab Republic); Eadan, Z. [Physics Department, Damascus University (Syrian Arab Republic); Amin, Y. [Department of Protection and Safety, Atomic Energy Commission of Syria, Damascus, P.O. Box 6091 (Syrian Arab Republic)

    2010-12-15

    Transfer factors of {sup 210}Po from soil to parsley and mint have been determined. Artificial polonium isotope ({sup 208}Po) was used as a tracer to determine transfer factor of Po from soil to plant in pot experiments. Two plant growing systems were used for this study namely, an outdoor system and a sheltered system by a polyethylene tent. {sup 208}Po and {sup 210}Po were determined in soil and different parts of the studied plants (stem and leaf), using alpha spectroscopy. The results have shown that there was a clear uptake of {sup 208}Po by roots to leaves and stems of both plants. Higher values of transfer factors using the {sup 210}Po activity concentrations than the {sup 208}Po activity concentration were observed. Transfer factors of {sup 210}Po from soil to parsley varied between 20 x 10{sup -2} and 50 x 10{sup -2} and 22 x 10{sup -3} and 67 x 10{sup -3} in mint, while {sup 208}Po transfer factors varied between 4 x 10{sup -2} and 12 x 10{sup -2} for parsley and 10 x 10{sup -2} and 22 x 10{sup -2} in mint. Transfer factors of Po were higher in those plants grown in the sheltered system than in the open system; about 75% of Po was transferred from atmosphere to parsley parts using the two systems. Ratios of transferred Po from soil to mint stem and leaf in the sheltered system were higher by 2 times from those in the open system.

  8. Differentiation of nitrous oxide emission factors for agricultural soils

    International Nuclear Information System (INIS)

    Lesschen, Jan Peter; Velthof, Gerard L.; Vries, Wim de; Kros, Johannes

    2011-01-01

    Nitrous oxide (N 2 O) direct soil emissions from agriculture are often estimated using the default IPCC emission factor (EF) of 1%. However, a large variation in EFs exists due to differences in environment, crops and management. We developed an approach to determine N 2 O EFs that depend on N-input sources and environmental factors. The starting point of the method was a monitoring study in which an EF of 1% was found. The conditions of this experiment were set as the reference from which the effects of 16 sources of N input, three soil types, two land-use types and annual precipitation on the N 2 O EF were estimated. The derived EF inference scheme performed on average better than the default IPCC EF. The use of differentiated EFs, including different regional conditions, allows accounting for the effects of more mitigation measures and offers European countries a possibility to use a Tier 2 approach. - Highlights: → We developed an N 2 O emission factor inference scheme for agricultural soils. → This scheme accounts for different N-input sources and environmental conditions. → The derived EF inference scheme performed better than the default IPCC EF. → The use of differentiated EFs allows for better accounting of mitigation measures. - Emission factors for nitrous oxide from agricultural soils are derived as a function of N-input sources and environmental conditions on the basis of empirical information.

  9. [Factors influencing nurses' organizational citizenship behavior].

    Science.gov (United States)

    Park, Junhee; Yun, Eunkyung; Han, Sangsook

    2009-08-01

    This study was conducted to identify the factors that influence nurses' organizational citizenship behavior. A cross-sectional design was used, with a convenience sample of 547 nurses from four university hospitals in Seoul and Gyeonggi province. The data were collected through a questionnaire survey done from September 22 to October 10, 2008. The tools used for this study were scales on organizational citizenship behavior (14 items), self-leadership (14 items), empowerment (10 items), organizational commitment (7 items), job satisfaction (8 items) and transformational.transactional leadership (14 items). Cronbach's alpha and factor analysis were examined to test reliability and construct validity of the scale. The data collected were processed using SPSS Window 15.0 Program for actual numbers and percentages, differences in the dependent variable according to general characteristics, and means, standard deviations, correlation coefficients and multiple regression analysis. The factors influencing nurses' organizational citizenship behavior were identified as self-leadership(beta=.247), empowerment (beta=.233), job satisfaction (beta=.209), organizational commitment (beta=.158), and transactional leadership (beta=.142). Five factors explained 42.0% of nurses' organizational citizenship behavior. The results of this study can be used to develop further management strategies for enhancement of nurses' organizational citizenship behavior.

  10. Influence of soil parameters on the linearity of the soil-to-plant transfer process of {sup 238}U and {sup 226}Ra

    Energy Technology Data Exchange (ETDEWEB)

    Blanco Rodriguez, P.; Vera Tome, F. [Natural Radioactivity Group. Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental. Universidad de Salamanca, 37008 Salamanca (Spain)

    2014-07-01

    Transfer from soil to plant is an important input of radionuclides into the food chain. Also, the mobility of radionuclides in soils is enhanced through their passage into the plant compartment. Thus, the soil-to-plant transfer of radionuclides raises the potential human dose. In radiological risk assessment models, this process is usually considered to be an equilibrium process such that the activity concentration in plants is linearly related to the soil concentration through a constant transfer factor (TF). However, the large variability present by measured TF values leads to major uncertainties in the assessment of risks. One possible way to reduce this variability in TF values is to parametrize their determination. This paper presents correlations of TF with the major element concentrations in soils. The findings confirm the major influence of the chemical environment of a soil on the assimilation process. The variability of TF might be greatly reduced if only the labile fraction were considered. Experiments performed with plants (Helianthus annuus L.) growing in a hydroponic medium appear to confirm this suggestion, showing a linear correlation between the plant and the soil solution activity concentrations. Extracting the labile fraction of a real soil is no trivial task, however. A possible operationally definable method is to consider the water-soluble together with the exchangeable fractions of the soil. Studies performed in granitic soils showed that the labile concentration of uranium and radium strongly depended on the soil's textural characteristics. In this sense, a parametrization is proposed of the labile uranium and radium concentration as a function of the soil's granulometric parameters. (authors)

  11. Transfer Factor of Radioactive Cs and Sr from Egyptian Soils to Roots and Leafs of Wheat Plant

    International Nuclear Information System (INIS)

    Abu Khadra, S.A.; Abdel Fattah, A.T.; Eissa, H.S.; Abdel Sabour, M.F.

    2009-01-01

    Transfer factors (TFs) of long lived radionuclide such as 137 Cs and 90 Sr from three different Egyptian soils type to wheat plant have been studied by radiotracer experiments. Most typical Egyptian soils (sandy, sandy loam and clayey) from three different locations (Al -Oboor, Abu- Zaabal and Shebeen cities) were selected for the experiments carried out under outdoor conditions. The plant selected was wheat because the high consumption of wheat in Egypt. In the present study radioactive strontium and caesium uptake from different types of soil was investigated .These radionuclide showed a considerable difference in their distribution within the plant .The results showed that soil type influences the transfer factors. Sandy soil resulted in the highest transfer factor for both (Cs and Sr) from soil to wheat. TFs for leafs were higher than those for roots in case of 90 Sr (for all types of soil). However, TFs of ( 137 Cs) for roots were higher than those for leafs for all soils. Grains of the wheat showed the lowest transfer factor for the Cs and Sr (for all types of soil)

  12. Analysis of factors controlling soil phosphorus loss with surface runoff in Huihe National Nature Reserve by principal component and path analysis methods.

    Science.gov (United States)

    He, Jing; Su, Derong; Lv, Shihai; Diao, Zhaoyan; Bu, He; Wo, Qiang

    2018-01-01

    Phosphorus (P) loss with surface runoff accounts for the P input to and acceleration of eutrophication of the freshwater. Many studies have focused on factors affecting P loss with surface runoff from soils, but rarely on the relationship among these factors. In the present study, rainfall simulation on P loss with surface runoff was conducted in Huihe National Nature Reserve, in Hulunbeier grassland, China, and the relationships between P loss with surface runoff, soil properties, and rainfall conditions were examined. Principal component analysis and path analysis were used to analyze the direct and indirect effects on P loss with surface runoff. The results showed that P loss with surface runoff was closely correlated with soil electrical conductivity, soil pH, soil Olsen P, soil total nitrogen (TN), soil total phosphorus (TP), and soil organic carbon (SOC). The main driving factors which influenced P loss with surface runoff were soil TN, soil pH, soil Olsen P, and soil water content. Path analysis and determination coefficient analysis indicated that the standard multiple regression equation for P loss with surface runoff and each main factor was Y = 7.429 - 0.439 soil TN - 6.834 soil pH + 1.721 soil Olsen-P + 0.183 soil water content (r = 0.487, p runoff. The effect of physical and chemical properties of undisturbed soils on P loss with surface runoff was discussed, and the soil water content and soil Olsen P were strongly positive influences on the P loss with surface runoff.

  13. The Behaviour of Laboratory Soil Electrical Resistivity Value under Basic Soil Properties Influences

    International Nuclear Information System (INIS)

    Hazreek, Z A M; Aziman, M; Azhar, A T S; Chitral, W D; Fauziah, A; Rosli, S

    2015-01-01

    Electrical resistivity method (ERM) was a popular indirect geophysical tools adopted in engineering, environmental and archaeological studies. In the past, results of the electrical resistivity value (ERV) were always subjected to a long discussion and debate among the related parties such as an engineers, geophysicists and geologists due to its lack of clarification and evidences in quantitative point of view. Most of the results produced in the past was always been justified using qualitative ways which difficult to be accept by certain parties. In order to reduce the knowledge gap between those parties, this study has performed a laboratory experiment of soil box resistivity test which supported by an additional basic geotechnical test as referred to particle size distribution test (d), moisture content test (w), density test (ρ bulk ) and Atterberg limit test (LL, PL and PI). The test was performed to establish a series of electrical resistivity value with different quantity of water content for Clayey SILT and Silty SAND soil. It was found that the ERV of Silty SAND (600 - 7300 Ωm) was higher than Clayey SILT (13 - 7700 Ωm) due to the different quantity of basic soil properties value obtained from the basic geotechnical test. This study was successfully demonstrated that the fluctuation of ERV has greatly influenced by the variations of the soil physical properties (d, w, ρ bulk , LL, PL and PI). Hence, the confidence level of ERV interpretation will be increasingly meaningful since it able to be proved by others parameter generated by laboratory direct test

  14. Internal factors influencing the knowledge continuity ensuring

    Directory of Open Access Journals (Sweden)

    Hana Urbancová

    2012-01-01

    Full Text Available The aim of the systematic ensuring of knowledge continuity is the continuity of an organisation’s development, the quality of managerial positions and the continuity of decision-making. By ensuring knowledge continuity, organisations may gain a performance-enhancing factor. The objective of the article is to identify the level of impact of decisive internal factors determining knowledge continuity ensuring and contributing to the efficiency of the organisations. Knowledge continuity ensuring as an internal force, however, can together with the right employees, help adapt more quickly to external conditions that organisations can hardly control. Monitoring and ensuring knowledge continuity can contribute to a higher quality of processes in general, in particular processes exploiting knowledge, and thus help improve the level of management. The first part of the article presents theoretical views on the aspects of knowledge continuity ensuring in organisations while the second part analyses the findings of the surveys carried out among managers in organisations in the Czech Republic. Based on the summary of the outcomes obtained it is possible to say that internal factors influence knowledge continuity ensuring in organisations, however, the level of impact of individual factors is determined by their size. The findings regarding the impact of each of the factors show that the most significant barriers to knowledge continuity ensuring are those associated with the human factor.

  15. Influence of relief and vegetation on soil properties in a disturbed chernozem soil landscape

    Science.gov (United States)

    Raab, Thomas; Hirsch, Florian; Vasserman, Oleksandr; Raab, Alexandra; Naeth, Anne

    2017-04-01

    In central and southeastern Alberta, chernozems dominate the soil landscape and are divided into several groups that follow the climate gradient from Northwest to Southeast: Dark Grey Chernozems, Black Chernozems, Dark Brown Chernozems; Brown Chernozems. Principles controlling development and distribution of these chernozem subtypes along the ecotone transect are quite well known. However, intensive land use over the last century has affected soils that originally have formed under natural conditions during the Holocene in more than 10,000 years. There is a lack of knowledge regarding soil development in these landscapes on the decadal to centennial time scale. Within this time frame the most important factor of soil formation may be relief, although this has not been properly studied. This study aims to compare soil properties in a typical chernozem landscape where soils have been highly disturbed and parent materials have been re-arranged by surface coal mining. We hypothesize that within 50 years, soils develop with significant differences based on vegetation type and slope aspect. Our study site is the former Diplomat Mine near Forestburg, Alberta where spoils form a small scale ridge and graben topography. The south facing slopes of the piles are covered by grassland, whereas on the north exposition has trees and shrubs. Samples were taken from six sites with differences in topography and vegetation type. Diplomate T1 is at the top of the ridge with grassland, Diplomate S1 is on the southern slope with grassland, Diplomate N1 is on the northern slope with trees, and Diplomate N2 is on the northern slope with shrubs. For comparison we took samples from two sites without slope aspect. One site was an undisturbed grassland (Diplomate Z1) and the other sites were reclaimed piles (Diplomate R1). At each site, five soil profiles were examined and volumetrically sampled (250 cm3 steel ring) in steps of five centimeters to a depth of 30 centimeters. We present first

  16. Influence of plant roots on electrical resistivity measurements of cultivated soil columns

    Science.gov (United States)

    Maloteau, Sophie; Blanchy, Guillaume; Javaux, Mathieu; Garré, Sarah

    2016-04-01

    Electrical resistivity methods have been widely used for the last 40 years in many fields: groundwater investigation, soil and water pollution, engineering application for subsurface surveys, etc. Many factors can influence the electrical resistivity of a media, and thus influence the ERT measurements. Among those factors, it is known that plant roots affect bulk electrical resistivity. However, this impact is not yet well understood. The goals of this experiment are to quantify the effect of plant roots on electrical resistivity of the soil subsurface and to map a plant roots system in space and time with ERT technique in a soil column. For this research, it is assumed that roots system affect the electrical properties of the rhizosphere. Indeed the root activity (by transporting ions, releasing exudates, changing the soil structure,…) will modify the rhizosphere electrical conductivity (Lobet G. et al, 2013). This experiment is included in a bigger research project about the influence of roots system on geophysics measurements. Measurements are made on cylinders of 45 cm high and a diameter of 20 cm, filled with saturated loam on which seeds of Brachypodium distachyon (L.) Beauv. are sowed. Columns are equipped with electrodes, TDR probes and temperature sensors. Experiments are conducted at Gembloux Agro-Bio Tech, in a growing chamber with controlled conditions: temperature of the air is fixed to 20° C, photoperiod is equal to 14 hours, photosynthetically active radiation is equal to 200 μmol m-2s-1, and air relative humidity is fixed to 80 %. Columns are fully saturated the first day of the measurements duration then no more irrigation is done till the end of the experiment. The poster will report the first results analysis of the electrical resistivity distribution in the soil columns through space and time. These results will be discussed according to the plant development and other controlled factors. Water content of the soil will also be detailed

  17. Factors influencing internal color of cooked meats.

    Science.gov (United States)

    Suman, Surendranath P; Nair, Mahesh N; Joseph, Poulson; Hunt, Melvin C

    2016-10-01

    This manuscript overviews the pertinent research on internal color of uncured cooked meats, biochemical processes involved in meat cookery, and fundamental mechanisms governing myoglobin thermal stability. Heat-induced denaturation of myoglobin, responsible for the characteristic dull-brown color of cooked meats, is influenced by a multitude of endogenous (i.e., pH, muscle source, species, redox state) and exogenous (i.e., packaging, ingredients, storage) factors. The interactions between these factors critically influence the internal cooked color and can confuse the consumers, who often perceive cooked color to be a reliable indicator for doneness and safety. While certain phenomena in cooked meat color are cosmetic in nature, others can mislead consumers and result in foodborne illnesses. Research in meat color suggests that processing technologies and cooking practices in industry as well as households influence the internal cooked color. Additionally, the guidelines of many international public health and regulatory authorities recommend using meat thermometers to determine safe cooking endpoint temperature and to ensure product safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Initial Soil Organic Matter Content Influences the Storage and Turnover of Litter-, Root- and Soil Carbon in Grasslands

    Science.gov (United States)

    Liu, L.; Xu, S.; Li, P.; Sayer, E. J.

    2017-12-01

    Grassland degradation is a worldwide problem that often leads to substantial loss of soil organic matter (SOM). Understanding how SOM content influences the stabilization of plant carbon (C) to form soil C is important to evaluate the potential of degraded grasslands to sequester additional C. We conducted a greenhouse experiment using C3 soils with six levels of SOM content and planted the C4 grass Cleistogenes squarrosa and/or added its litter to investigate how SOM content regulates the storage of new soil C derived from litter and roots, the decomposition of extant soil C, and the formation of soil aggregates. We found that microbial biomass carbon (MBC) increased with SOM content, and increased the mineralization of litter C. Both litter addition and planted treatments increased the amount of new C inputs to soil. However, litter addition had no significant impacts on the mineralization of extant soil C, but the presence of living roots significantly accelerated it. Thus, by the end of the experiment, soil C content was significantly higher in the litter addition treatments, but was not affected by planted treatments. The soil macroaggregate fraction increased with SOM content and was positively related to MBC. Overall, our study suggests that as SOM content increases, plant growth and soil microbes become more active, which allows microbes to process more plant-derived C and increases new soil C formation. The interactions between SOM content and plant C inputs should be considered when evaluating soil C turnover in degraded grasslands.

  19. 3.4. Durability of soil-cement mixtures influenced by hostile environment

    International Nuclear Information System (INIS)

    Saidov, D.Kh.

    2011-01-01

    It is determined that soil-cement mixture is one of most perspective materials, that can substitute concrete. Experiments on revelation of magnesium sulphate influence on soil-cement mixtures were carried out. Data on granulometric composition and physical parameters of loess soils is presented in this article. Portland cement M 400 was used as binder. According to the results it is concluded that stability of soil-cement mixtures from loess soils in solutions of magnesium sulphate depends on concentration of solution.

  20. Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

    International Nuclear Information System (INIS)

    Pauget, B.; Gimbert, F.; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

    2012-01-01

    Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO 4 , EDTA, CaCl 2 , NH 4 NO 3 , NaNO 3 , free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r² adj = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r² adj = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: ► New approach to identify chemical methods able to predict metal bioavailability to snails. ► Bioavailability of cadmium, lead and zinc to snails was determined by

  1. Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

    Energy Technology Data Exchange (ETDEWEB)

    Pauget, B.; Gimbert, F., E-mail: frederic.gimbert@univ-fcomte.fr; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

    2012-08-01

    Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO{sub 4}, EDTA, CaCl{sub 2}, NH{sub 4}NO{sub 3}, NaNO{sub 3}, free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r Superscript-Two {sub adj} = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r Superscript-Two {sub adj} = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: Black-Right-Pointing-Pointer New approach to identify chemical methods able to predict metal bioavailability

  2. INFLUENCE OF NPK AND LIME APLICATION ON ERVA-MATE GROWTH, ROOT-ROT SEVERITY AND SOIL FUNGI POPULATION1

    Directory of Open Access Journals (Sweden)

    Igor Poletto

    2011-09-01

    Full Text Available The present work evaluated the influence of the application of NPK and liming doses in the soil, on the growth of Erva-mate, the severity of rot-root and the fungi population of the soil. To do so, an experiment was installed at the green house, in the Forest Nursery of UFSM, using an experimental design completely randomized factorial 4x3x4 (Factor F: Fusarium spp. inoculation; Factor C: soil limestone; Factor A: NPK doses , totaling 48 treatments. The seedlings were cultivated in vases containing 2 kg of soil, classified as ‘Red-Yellow Argisoil’ (clay soil. At the end of the experiment was measured the stem diameter, height of the aerial part, leaves number, aerial dry biomass, root dry biomass and total dry biomass of the seedlings. Also, the soil was collected, from each treatment, for the chemical analysis and the counting of the fungi population. It was observed that the association among application of NPK and liming in the soil hampered the development of Erva-mate seedlings. The analysis of some variables suggests that the limestone absence provided greater resistance of seedlings to the attack of Fusarium spp. or the severity of Fusarium spp. was reduced in lower pH. The fungi population of the soil presented varied behavior depending on the applied treatments.

  3. [Distribution of 137Cs and relative influencing factors on typical karst sloping land].

    Science.gov (United States)

    Zhang, Xiao-Nan; Wang, Ke-Lin; Zhang, Wei; Chen, Hong-Song; He, Xun-Yang; Zhang, Xin-Bao

    2009-11-01

    Based on the field survey and the analysis of a large number of soil samples, the distribution of 137 Cs and its influencing factors were studied using 137 Cs tracer technology on typical karst sloping land. The results indicate that the distribution of 137 Cs in soil profile in karst areas show the similar characteristics as that in non-karst areas, fitted an exponential pattern in forest soils and a uniform pattern in cultivated soils. In the sinkhole points in karst areas, 137 Cs exists in deep soil layers and its specific activity vary from 1.7 to 3.3 Bq/kg in soil layers above 45cm, suggesting the existing soil around karst sinkhole is mainly formed by the accumulation of erosion materials. The 137 Cs specific activity in the soil from two rock cracks are 16.8 Bq/kg and 37.6 Bq/kg respectively, which are much higher than that in the soil around the rock, this phenomenon indicates that bare rock is an important influencing factor for 137 Cs spatial movement. With the increment of altitude, the 137 Cs area activity exhibits an irregular fluctuation and evident spatial heterogeneity. On the forest land, the 137 Cs area activities which range from 299.4 to 1 592.6 Bq/m2 are highly positively correlated with the slope gradient and positively correlated with the altitude; while on the cultivated land, the 137 Cs area activities which range from 115.8 to 1478.6 Bq/m2 are negatively correlated with the slope gradient but negatively correlated with the altitude. Topography, geomorphology and human disturbance intensity are the key factors influencing 137 Cs spatial distribution.

  4. An investigation of factors influencing indoor radon concentrations

    International Nuclear Information System (INIS)

    Majborn, B.; Soerensen, A.; Nielsen, S.P.; Boetter-Jensen, L.

    1988-05-01

    Variations in indoor radon concentrations and some influencing factors have been studied during a two-year period (1986-1987) in 16 almost identical single-family houses.The annual average radon concentration in the houses varied from about 50 to about 400 Bq/m 3 . Variations in soil characteristics and radon concentration in soil gas could not be directly related to the variations of the average indoor radon concentrations. Most of the houses showed a ''normal'' seasonal variation of the radon concentration with a maximum in the winter and minimum in the summer. A deviating seasonal variation was found in three of the houses. Hourly data obtained in one unoccupied house during a period of 2-1/2 months showed no or only weak correlations between the indoor radon concentration and meteorological factors. However, for most of the houses, the seasonal variation of the indoor radon concentration was well correlated with the average indoor-outdoor temperature difference on a 2-month basis. It was demonstrated that the radon concentration can be strongly reduced in the Risoe houses if a district-heating duct, which is connected to all the houses, is ventilated, so that a slightly lowered pressure is maintained in the duct. 5 taps., 24 ill. (author)

  5. Factors influencing thermal tolerances of individual organisms

    International Nuclear Information System (INIS)

    Hutchison, V.H.

    1976-01-01

    The diversity of experimental methods and terminology employed by investigators to measure the effects of high temperatures on individual organisms, plus the often overlooked complexities of the holocoenotic environment, has often led to disconcerting conclusions. A plea is made for standardization of testing methods and for a wider appreciation of factors that may alter thermal tolerances. The influence of elevated temperature is grouped into three categories, lethal effects, controlling effects, and directive effects, all of which should be considered in assessing the impact of thermal effluent on organisms. In addition, the terminology (acclimation, acclimatization, adaptation, habituation, lethal temperature, critical thermal maximum, etc.) needs standardized definitions. The important factors influencing thermal effects on organisms include photoperiod, seasonal and daily cycles, geographic variation, diet, sex, breeding condition, age, life-cycle stage, salinity, chemicals, body water content and partitioning, oxygen supply, pH, innate and learned behavior, history of thermal exposure, sublethal exposure to limiting factors, and experimental methods. Examples of most of these are given to illustrate the role of temperature in the holocoenotic environmental complex of individual organisms

  6. Influence of hydrological regime on pore water metal concentrations in a contaminated sediment-derived soil

    International Nuclear Information System (INIS)

    Du Laing, G.; Vanthuyne, D.R.J.; Vandecasteele, B.; Tack, F.M.G.; Verloo, M.G.

    2007-01-01

    Options for wetland creation or restoration might be limited because of the presence of contaminants in the soil. The influence of hydrological management on the pore water concentrations of Cd, Cr, Cu, Fe, Mn, Ni and Zn in the upper soil layer of a contaminated overbank sedimentation zone was investigated in a greenhouse experiment. Flooding conditions led to increased Fe, Mn, Ni and Cr concentrations and decreased Cd, Cu and Zn concentrations in the pore water of the upper soil layer. Keeping the soil at field capacity resulted in a low pore water concentration of Fe, Mn and Ni while the Cd, Cu, Cr and Zn concentrations increased. Alternating hydrological conditions caused metal concentrations in the pore water to fluctuate. Formation and re-oxidation of small amounts of sulphides appeared dominant in determining the mobility of Cd, Cu, and to a lesser extent Zn, while Ni behaviour was consistent with Fe/Mn oxidation and reduction. These effects were strongly dependent on the duration of the flooded periods. The shorter the flooded periods, the better the metal concentrations could be linked to the mobility of Ca in the pore water, which is attributed to a fluctuating CO 2 pressure. - The hydrological regime is a key factor in determining the metal concentration in the pore water of a contaminated sediment-derived soil

  7. Emergency Department Crowding: Factors Influencing Flow

    Directory of Open Access Journals (Sweden)

    Arkun, Alp

    2010-02-01

    Full Text Available Background: The objective of this study was to evaluate those factors, both intrinsic and extrinsic to the emergency department (ED that influence two specific components of throughput: “door-to-doctor” time and dwell time.Methods: We used a prospective observational study design to determine the variables that played a significant role in determining ED flow. All adult patients seen or waiting to be seen in the ED were observed at 8pm (Monday-Friday during a three-month period. Variables measured included daily ED volume, patient acuity, staffing, ED occupancy, daily admissions, ED boarder volume, hospital volume, and intensive care unit volume. Both log-rank tests and time-to-wait (survival proportional-hazard regression models were fitted to determine which variables were most significant in predicting “door-to-doctor” and dwell times, with full account of the censoring for some patients.Results: We captured 1,543 patients during our study period, representing 27% of total daily volume. The ED operated at an average of 85% capacity (61-102% with an average of 27% boarding. Median “door-to-doctor” time was 1.8 hours, with the biggest influence being triage category, day of the week, and ED occupancy. Median dwell time was 5.5 hours with similar variable influences.Conclusion: The largest contributors to decreased patient flow through the ED at our institution were triage category, ED occupancy, and day of the week. Although the statistically significant factors influencing patient throughput at our institution involve problems with inflow, an increase in ED occupancy could be due to substantial outflow obstruction and may indicate the necessity for increased capacity both within the ED and hospital. [West J Emerg Med. 2010; 11(1:10-15

  8. Emergency department crowding: factors influencing flow.

    Science.gov (United States)

    Arkun, Alp; Briggs, William M; Patel, Sweha; Datillo, Paris A; Bove, Joseph; Birkhahn, Robert H

    2010-02-01

    THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE THOSE FACTORS, BOTH INTRINSIC AND EXTRINSIC TO THE EMERGENCY DEPARTMENT (ED) THAT INFLUENCE TWO SPECIFIC COMPONENTS OF THROUGHPUT: "door-to-doctor" time and dwell time. We used a prospective observational study design to determine the variables that played a significant role in determining ED flow. All adult patients seen or waiting to be seen in the ED were observed at 8pm (Monday-Friday) during a three-month period. Variables measured included daily ED volume, patient acuity, staffing, ED occupancy, daily admissions, ED boarder volume, hospital volume, and intensive care unit volume. Both log-rank tests and time-to-wait (survival) proportional-hazard regression models were fitted to determine which variables were most significant in predicting "door-to-doctor" and dwell times, with full account of the censoring for some patients. We captured 1,543 patients during our study period, representing 27% of total daily volume. The ED operated at an average of 85% capacity (61-102%) with an average of 27% boarding. Median "door-to-doctor" time was 1.8 hours, with the biggest influence being triage category, day of the week, and ED occupancy. Median dwell time was 5.5 hours with similar variable influences. The largest contributors to decreased patient flow through the ED at our institution were triage category, ED occupancy, and day of the week. Although the statistically significant factors influencing patient throughput at our institution involve problems with inflow, an increase in ED occupancy could be due to substantial outflow obstruction and may indicate the necessity for increased capacity both within the ED and hospital.

  9. Soil to plant transfer factor of radiocesium by pot experiment

    International Nuclear Information System (INIS)

    Jalil, A.; Rahman, M.M.; Koddus, A.; Chand, M.M.; Zaman, M.A.; Ahmad, G.U.

    2002-01-01

    This paper deals with the soil to plant transfer factor (TF) of radiocesium (Cs 137 ) considered to be an important parameter while calculating radiological doses due to the potential release of radionuclides into the environment. In the present work, TF values were measured for the main foodstuffs in Bangladesh such as leafy vegetables (Lalshak, Palangshak), Ladyfinger, Radish, Potato, Potato Plant, Paddy, Paddy plant, Grass, Ginger, Ginger plant, Turmeric, and Turmeric plant by pot experiments grown in the AERE soil. Soil characteristics have also been investigated to assist the measured values of the corresponding radionuclide. TF values of the leafy parts and products of the corresponding plants were found in the range of 2.02x10 -1 to 1.8x10 -2 , which are reasonably comparable with the value found in the literature. It has been observed that the TF values in the leafy part of the plants are higher than the products. (author)

  10. [New nurse turnover intention and influencing factors].

    Science.gov (United States)

    Han, Sang Sook; Sohn, In Soon; Kim, Nam Eun

    2009-12-01

    The study was done to identify turnover intention in new nurses according to characteristics of the nurses and other factors affecting turnover and to provide data to set up a strategy to reduce the turnover. Data were collected from 1,077 new nurses who had less than 12 months employment experience and worked in one of 188 hospitals. Eight research instruments were used. Data analysis was done using SPSS WIN 15.0 program. Several factors influence new nurse turnover intention. The average score for turnover intention was 2.12. The scores for subscales were self efficacy, 3.76, nursing performance, 3.90, job satisfaction, 2.09, organization commitment, 1.28, stress, 1.32, burnout, 2.82 and nursing organizational culture, 3.29. Turnover intention was related to self efficacy, nursing performance, job satisfaction, organization commitment, stress, burnout, nursing organizational culture, duration of in-class training, duration of on the job training, number of hospital beds, length of employment and duration of employment in current workplace. The predicting factors for turnover intention were burnout, stress, duration of employment in the current workplace, self efficacy and nursing performance. Those factors explained 51.6% of turnover intention. New nurse turnover intention can be reduced by mitigating the factors affecting this intention.

  11. Factors influencing economic performance of the South Moravian Region

    Directory of Open Access Journals (Sweden)

    Iva Živělová

    2011-01-01

    Full Text Available The paper deals with selected factors influencing economic performance of the South Moravian Region in the years 2003–2009. The economic performance of the region is evaluated by means of a contribution to the Gross Domestic Product of the Czech Republic. Considering the fact that the level of economic activity depends on the exploitation rate of production factors in the considered region, both development of soil exploitation rate and development of labour market indicators correlated with working force utilization are analysed, a number of employed adults and registered unemployment are taken into consideration. Attention is paid to the economic activity rate. The formation of the Gross Fixed Capital, which an assumption of favourable economic performance, and development of Gross Added Value are evaluated.All the regions nowadays fumble with the negative impacts of the economic crisis. According to the analysis of the economic performance of the South Moravian Region and the analysis of the factors influencing this performance, it could be stated, that the development of the South Moravian Region could be evaluated quite positively.

  12. Emergency Department Crowding: Factors Influencing Flow

    OpenAIRE

    Arkun, Alp; Briggs, William M; Patel, Sweha; Datillo, Paris A; Bove, Joseph; Birkhahn, Robert H

    2010-01-01

    Background: The objective of this study was to evaluate those factors, both intrinsic and extrinsic to the emergency department (ED) that influence two specific components of throughput: “door-to-doctor” time and dwell time. Methods: We used a prospective observational study design to determine the variables that played a significant role in determining ED flow. All adult patients seen or waiting to be seen in the ED were observed at 8pm (Monday-Friday) during a three-month period. V...

  13. Factors influencing variation in dentist service rates.

    Science.gov (United States)

    Grembowski, D; Milgrom, P; Fiset, L

    1990-01-01

    In the previous article, we calculated dentist service rates for 200 general dentists based on a homogeneous, well-educated, upper-middle-class population of patients. Wide variations in the rates were detected. In this analysis, factors influencing variation in the rates were identified. Variation in rates for categories of dental services was explained by practice characteristics, patient exposure to fluoridated water supplies, and non-price competition in the dental market. Rates were greatest in large, busy practices in markets with high fees. Older practices consistently had lower rates across services. As a whole, these variables explained between 5 and 30 percent of the variation in the rates.

  14. Discriminating impacts of geomorphological and human factors on vineyard soil erosion (Burgundy, France)

    Science.gov (United States)

    Chevigny, Emmanuel; Quiquerez, Amélie; Petit, Christophe; Curmi, Pierre

    2014-05-01

    The Burgundy vineyards have been recognized for the high diversity of Terroirs, controlled by complex interactions between natural features, historical parameters and soil management practices. Vineyards are known to undergo substantial soil loss in comparison with other types of agricultural land. Hydric erosion on vineyards is controlled by complex interactions of natural and anthropogenic factors leading to intra-plot spatial heterogeneities of topsoil at a scale of a metre. Studying the relationship between soils and their degradation is crucial in this situation where soil sustainability is threatened. This study explores the relative influences of historical and present-day anthropogenic factors and geomorphological processes controlling soil erosion on vineyard hillslopes. The selected area was located in the Monthelie vineyard (Côte de Beaune, France) where intensive erosion occurred during high-intensity rainfall events. Soil erosion quantification was performed at a square-metre scale using dendrogeomorphology. This method is based on the measurement of the unearthing of the stock located on the vine plants, considered as a passive marker of soil-surface vertical displacement since the year of plantation. The obtained maps, together with various complementary datasets, such as geological and geomorphological data, but also historical documents (cadastral plans, cadastral matrices and old aerial photographs) allow landscape evolution to be assessed. The combination of all these data shows that spatial distribution and intensity of erosion are controlled mainly by lithology and slope value. However, our study highlights that the sediment dynamics in this vineyard plot is highly related to historical former plot limits and present-day management practices. Nonetheless, quantification of sediment dynamic for the last decade reveals that the impacts of historical structures are disappearing gradually, in response to present-day management practices and

  15. Soil-to-potato transfer factors of elements

    International Nuclear Information System (INIS)

    Tsukada, Hirofumi; Watabe, Teruhisa.

    1996-01-01

    Transfer factors (TFs) of stable elements from soil to potato were determined for 26 pairs of samples which were collected at different sites in Aomori prefecture, Japan. The concentrations of 31 elements in both soil and potato samples were determined by neutron activation analysis. Several of these elements were divided into two groups, each having different TF characteristics. In the first group of elements, such as Cl, K, Ca, etc., an inverse correlation was seen between the TFs for each element and their concentrations in the soil. The relatively constant concentrations of these elements in potato were independent of the concentrations of the same elements in soil. However, in the second group, the TFs for other elements, such as Sc, Co and so on, in potato were independent of their concentrations in the soil. The fluctuation of TF observed in this study was smaller than that previously reported. It may be attributed to the fact that the experiment was done in a relatively narrow geographic area. In addition, the TFs for stable elements in this study were generally one to three orders of magnitude lower than those compiled for radioactive isotopes in IAEA publications. These differences should be precisely examined hereafter. (author)

  16. Factors influencing the cardiac MIBG accumulation

    International Nuclear Information System (INIS)

    Takatsu, Hisato; Fujiwara, Hisayoshi

    1997-01-01

    Following factors possibly influencing the cardiac MIBG accumulation were examined mainly in mice. 1. The specific activity of the MIBG (meta-iodo-benzyl guanidine) on the neuronal and non-neuronal fractions. 2. Motor restriction stress on MIBG accumulation and washout. 3. Loading and restriction of sodium chloride on the accumulation and effect of suppression of renin-angiotensin system. 4. Examinations in Dahl rats. 125I- or 131I-MIBG was intravenously administered to mice at 74 kBq. At 30 min or 4 hr after administration, mice were sacrificed and their left ventricles were dissected out for measurement of radioactivity in a liquid scintillation counter. Salt-sensitive and -resistant Dahl rats were given with 37 MBq of 123I-MIBG and cardiac radioactivity was measured externally for calculation of washout. Factors examined were found highly correlated with the accumulation of MIBG and measurement of its washout was considered useful for evaluating sympathetic activity. (K.H.)

  17. A survey on factors influencing city branding

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Mahmoudzadeh

    2014-10-01

    Full Text Available Nowadays, the issue of “globalization” is entering to all areas in the world. In addition to products and companies, cities and countries also have the opportunity to see themselves as important actors in international arena. Places define their positions in different fields like business, leisure and recreation, educational opportunities, living, etc. This paper presents an empirical study to introduce city branding as one of the solutions to join globalization process. The method of this research is based on the “descriptive-analytic” and utilize the available literature and experts’ opinions to prioritize the influencing factors of city branding. We use Delphi consensus methods and technique of analytical hierarchy process to evaluate the factors. Finally, the results of the study indicate that security, transportation and mental creativity are the weakest fields and business and shopping facilities are strong fields of city branding in metropolitan of Tehran.

  18. Organizational factors influencing improvements in safety

    International Nuclear Information System (INIS)

    Marcus, A.; Nichols, M.L.; Olson, J.; Osborn, R.; Thurber, J.

    1992-01-01

    Research reported here seeks to identify the key organizational factors that influence safety-related performance indicators in nuclear power plants over time. It builds upon organizational factors identified in NUREG/CR-5437, and begins to develop a theory of safety-related performance and performance improvement based on economic and behavioral theories of the firm. Central to the theory are concepts of past performance, problem recognition, resource availability, resource allocation, and business strategies that focus attention. Variables which reflect those concepts are combined in statistical models and tested for their ability to explain scrams, safety system actuations, significant events, safety system failures, radiation exposure, and critical hours. Results show the performance indicators differ with respect to the sets of variables which serve as the best predictors of future performance, and past performance is the most consistent predictor of future performance

  19. Seasonal abundance of soil arthropods in relation to meteorological and edaphic factors in the agroecosystems of Faisalabad, Punjab, Pakistan

    Science.gov (United States)

    Shakir, Muhammad Mussadiq; Ahmed, Sohail

    2015-05-01

    Soil arthropods are an important component of agroecosystems, contributing significantly to their biodiversity and functioning. However, seasonal patterns, population dynamics, and significant roles of these soil arthropods in improvement of soil structures and functions are influenced by many factors. The objective of the current study was to investigate soil arthropod abundance in relation to a blend of meteorological and edaphic factors and to find out the difference in abundance among various crops (sugarcane, cotton, wheat, alfalfa fodder, and citrus orchards). The arthropod sampling was done by pitfall traps and Tullgren extractions on fortnightly intervals. Soil temperature and relative humidity were noted on the field sites while analysis for soil pH, organic matter, and soil moisture contents were done in the laboratory. The rainfall data was obtained from an observatory. Results showed that significant differences were found in soil arthropod abundance across different sampling months and crops. Out of total 13,673 soil arthropods sampled, 38 % belonged to Collembola, followed by 15 % Hymenoptera, 15 % Acarina, 11 % Myriapods, 6 % Coleoptera, 5 % Orthoptera, and 5 % Araneae. Mean abundance per sample was highest in summer months as compared to winter. Overall abundance per sample was significantly different between all crops ( p Aranae, Coleoptera), least abundant (Dermaptera, Hemiptera, Diptera), and rare (Blattaria, Isoptera, Diplura, Lepidoptera). Soil temperature and soil organic matter showed significant positive correlation with abundance, while relative humidity was significantly negatively correlated. Soil moisture and soil pH showed no significant correlations while no correlation was found with total rainfall. PCA analysis revealed that soil surface arthropods were the major contributors of variation in overall abundance in extreme temperature months while microarthropods in low-temperature months. CCA analysis revealed the occurrence of

  20. Seasonal abundance of soil arthropods in relation to meteorological and edaphic factors in the agroecosystems of Faisalabad, Punjab, Pakistan.

    Science.gov (United States)

    Shakir, Muhammad Mussadiq; Ahmed, Sohail

    2015-05-01

    Soil arthropods are an important component of agroecosystems, contributing significantly to their biodiversity and functioning. However, seasonal patterns, population dynamics, and significant roles of these soil arthropods in improvement of soil structures and functions are influenced by many factors. The objective of the current study was to investigate soil arthropod abundance in relation to a blend of meteorological and edaphic factors and to find out the difference in abundance among various crops (sugarcane, cotton, wheat, alfalfa fodder, and citrus orchards). The arthropod sampling was done by pitfall traps and Tullgren extractions on fortnightly intervals. Soil temperature and relative humidity were noted on the field sites while analysis for soil pH, organic matter, and soil moisture contents were done in the laboratory. The rainfall data was obtained from an observatory. Results showed that significant differences were found in soil arthropod abundance across different sampling months and crops. Out of total 13,673 soil arthropods sampled, 38 % belonged to Collembola, followed by 15 % Hymenoptera, 15 % Acarina, 11 % Myriapods, 6 % Coleoptera, 5 % Orthoptera, and 5 % Araneae. Mean abundance per sample was highest in summer months as compared to winter. Overall abundance per sample was significantly different between all crops (p arthropods according to abundance, i.e., highly abundant (Collembola, Acarina, Myripoda, Hymenoptera), moderately abundant (Orthoptera, Aranae, Coleoptera), least abundant (Dermaptera, Hemiptera, Diptera), and rare (Blattaria, Isoptera, Diplura, Lepidoptera). Soil temperature and soil organic matter showed significant positive correlation with abundance, while relative humidity was significantly negatively correlated. Soil moisture and soil pH showed no significant correlations while no correlation was found with total rainfall. PCA analysis revealed that soil surface arthropods were the major contributors of variation in overall

  1. Influence of Soil Based Growing Media on Vegetative Propagation of Selected Cultivars of Olea Europaea

    International Nuclear Information System (INIS)

    Ahmed, M. I.; Ashraf, M. I.; Malik, S. U.; Husaain, Q.

    2016-01-01

    Pothwar region of Pakistan is a natural habitat of Olea spp. There is a high demand of certified olive plants to establish olive orchids in the region, because native wild species are non-fruit bearing. Plants of certified fruit bearing olive (Olea europaea L.) cultivars are rarely available. Vegetative propagation of olive is highly responsive to texture of soil based growing media. This study examined the effect of growing media composition (soil texture and nutrients) on vegetative propagation of five cultivars of olive. The experiment was carried out in randomized complete block design (RCBD) with two factors factorial having 25 repeats of each four treatments. Plant growth and survival data were collected and analyzed for the influence of soil attributes. In sandy loam soil, cv. Bari-1 had 82 percent plant survival, highest number of roots per plant (3.5), and longest root length (13.01 cm). Highest number of shoots per plant (4.25) and maximum shoot length (15.64 cm) were also recorded for Bari-1 with sandy loam growing media. Silt loam soil is least suitable growing media for vegetative propagation of olive. In the silt loam soil, plants survival rate was 59 percent for cv. Gemlik, number of roots per plant was 1.5 for cv. Ottobrattica, minimum root length 5.65 cm, minimum number of shoots per plant one, and minimum shoot length 7.42 cm were recorded for cv. Pendolino with silt loam soil. Results suggested that sandy loam growing media is better than the others for vegetative propagation of olive. Cultivar Bari-1 performed better than the others examined in this study by indicating highest (1) survival percentage, (2) root and shoot length, and (3) number of roots and shoots produced within a specific period of time. (author)

  2. Automation bias: empirical results assessing influencing factors.

    Science.gov (United States)

    Goddard, Kate; Roudsari, Abdul; Wyatt, Jeremy C

    2014-05-01

    To investigate the rate of automation bias - the propensity of people to over rely on automated advice and the factors associated with it. Tested factors were attitudinal - trust and confidence, non-attitudinal - decision support experience and clinical experience, and environmental - task difficulty. The paradigm of simulated decision support advice within a prescribing context was used. The study employed within participant before-after design, whereby 26 UK NHS General Practitioners were shown 20 hypothetical prescribing scenarios with prevalidated correct and incorrect answers - advice was incorrect in 6 scenarios. They were asked to prescribe for each case, followed by being shown simulated advice. Participants were then asked whether they wished to change their prescription, and the post-advice prescription was recorded. Rate of overall decision switching was captured. Automation bias was measured by negative consultations - correct to incorrect prescription switching. Participants changed prescriptions in 22.5% of scenarios. The pre-advice accuracy rate of the clinicians was 50.38%, which improved to 58.27% post-advice. The CDSS improved the decision accuracy in 13.1% of prescribing cases. The rate of automation bias, as measured by decision switches from correct pre-advice, to incorrect post-advice was 5.2% of all cases - a net improvement of 8%. More immediate factors such as trust in the specific CDSS, decision confidence, and task difficulty influenced rate of decision switching. Lower clinical experience was associated with more decision switching. Age, DSS experience and trust in CDSS generally were not significantly associated with decision switching. This study adds to the literature surrounding automation bias in terms of its potential frequency and influencing factors. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Factors influencing global antiretroviral procurement prices.

    Science.gov (United States)

    Wirtz, Veronika J; Forsythe, Steven; Valencia-Mendoza, Atanacio; Bautista-Arredondo, Sergio

    2009-11-18

    Antiretroviral medicines (ARVs) are one of the most costly parts of HIV/AIDS treatment. Many countries are struggling to provide universal access to ARVs for all people living with HIV and AIDS. Although substantial price reductions of ARVs have occurred, especially between 2002 and 2008, achieving sustainable access for the next several decades remains a major challenge for most low- and middle-income countries. The objectives of the present study were twofold: first, to analyze global ARV prices between 2005 and 2008 and associated factors, particularly procurement methods and key donor policies on ARV procurement efficiency; second, to discuss the options of procurement processes and policies that should be considered when implementing or reforming access to ARV programs. An ARV-medicines price-analysis was carried out using the Global Price Reporting Mechanism from the World Health Organization. For a selection of 12 ARVs, global median prices and price variation were calculated. Linear regression models for each ARV were used to identify factors that were associated with lower procurement prices. Logistic regression models were used to identify the characteristics of those countries which procure below the highest and lowest direct manufactured costs. Three key factors appear to have an influence on a country's ARV prices: (a) whether the product is generic or not; (b) the socioeconomic status of the country; (c) whether the country is a member of the Clinton HIV/AIDS Initiative. Factors which did not influence procurement below the highest direct manufactured costs were HIV prevalence, procurement volume, whether the country belongs to the least developed countries or a focus country of the United States President's Emergency Plan For AIDS Relief. One of the principal mechanisms that can help to lower prices for ARV over the next several decades is increasing procurement efficiency. Benchmarking prices could be one useful tool to achieve this.

  4. Influence of land use on bacterial and archaeal diversity and community structures in three natural ecosystems and one agricultural soil.

    Science.gov (United States)

    Lynn, Tin Mar; Liu, Qiong; Hu, Yajun; Yuan, Hongzhao; Wu, Xiaohong; Khai, Aye Aye; Wu, Jinshui; Ge, Tida

    2017-07-01

    Studying shifts in microbial communities under different land use can help in determining the impact of land use on microbial diversity. In this study, we analyzed four different land-use types to determine their bacterial and archaeal diversity and abundance. Three natural ecosystems, that is, wetland (WL), grassland (GL), and forest (FR) soils, and one agricultural soil, that is, tea plantation (TP) soil, were investigated to determine how land use shapes bacterial and archaeal diversity. For this purpose, molecular analyses, such as quantitative polymerase chain reaction (Q-PCR), 16S rRNA gene sequencing, and terminal restriction fragment length polymorphism (T-RFLP), were used. Soil physicochemical properties were determined, and statistical analyses were performed to identify the key factors affecting microbial diversity in these soils. Phylogenetic affiliations determined using the Ribosomal Database Project (RDP) database and T-RFLP revealed that the soils had differing bacterial diversity. WL soil was rich in only Proteobacteria, whereas GR soil was rich in Proteobacteria, followed by Actinobacteria. FR soil had higher abundance of Chloroflexi species than these soils. TP soil was rich in Actinobacteria, followed by Chloroflexi, Acidobacteria, Proteobacteria, and Firmicutes. The archaeal diversity of GL and FR soils was similar in that most of their sequences were closely related to Nitrososphaerales (Thaumarchaeota phylum). In contrast, WL soil, followed by TP soil, had greater archaeal diversity than other soils. Eight different archaeal classes were found in WL soil, and Pacearchaeota class was the richest one. The abundance of bacterial and archaeal 16S rRNA gene copies in WL and GL soils was significantly higher than that in FR and TP soils. Redundancy analysis showed that bacterial diversity was influenced by abiotic factors, e.g., total organic carbon and pH, whereas total nitrogen, pH, and cation exchange capacity (CEC) significantly affected

  5. Factors influencing groundwater quality: towards an integrated management approach.

    Science.gov (United States)

    De Giglio, O; Quaranta, A; Barbuti, G; Napoli, C; Caggiano, G; Montagna, M T

    2015-01-01

    The safety of groundwater resources is a serious issue, particularly when these resources are the main source of water for drinking, irrigation and industrial use in coastal areas. In Italy, 85% of the water used by the public is of underground origin. The aim of this report is to analyze the main factors that make groundwater vulnerable. Soil characteristics and filtration capacity can promote or hinder the diffusion of environmental contaminants. Global climate change influences the prevalence and degree of groundwater contamination. Anthropic pressure causes considerable exploitation of water resources, leading to reduced water availability and the progressive deterioration of water quality. Management of water quality will require a multidisciplinary, dynamic and practical approach focused on identifying the measures necessary to reduce contamination and mitigate the risks associated with the use of contaminated water resources.

  6. Factors influencing seed germination in Cerrado grasses

    Directory of Open Access Journals (Sweden)

    Rosana Marta Kolb

    2016-03-01

    Full Text Available Few studies address the ecology of herbs of Cerrado grasslands, which are ecosystems where the long dry season, high temperatures, insolation, fire and invasive grasses greatly influencing germination and the establishment of plants. We assessed germination of 13 species of Poaceae from Cerrado grasslands under nursery conditions or in germination chambers, the latter with i recently collected seeds and seeds after six months storage, ii under constant and alternating temperatures, and iii in the presence and absence of light. Germinability, mean germination time (MGT and required light were quantified to elucidate factors involved in successful germination. Germinability was low for most grasses, probably because of low seed viability. For most species, germinability and MGT were not altered by seed storage. Germination percentages were higher at alternating temperatures and in the presence of light, factors that are more similar to natural environmental situations compared with constant temperature or the absence of light. Our findings indicate that alternating temperatures and light incidence are key factors for germination of species of Poaceae. The maintenance of these environmental factors, which are crucial for the conservation of Cerrado grasslands, depends on appropriate management interventions, such as fire management and the control of biological invasion.

  7. Factors that influence nurses' job satisfaction.

    Science.gov (United States)

    Ma, Chen-Chung; Samuels, Michael E; Alexander, Judith W

    2003-05-01

    To examine factors affecting the job satisfaction of registered nurses (RNs). A growing recognition of job dissatisfaction among RNs in South Carolina hospitals has contributed to current problems with recruitment and retention. If administrators identify factors influencing RNs' job satisfaction in hospitals and implement strategies to address these factors, RN turnover rates will decrease and recruiting and retention rates will increase. A cross-sectional study of secondary data was designed to identify the individual, work, and geographic factors that impact nursing job satisfaction at the state level. A 27-question self-administered survey was sent to 17,500 RNs in South Carolina with postage-paid envelopes for their responses. Surveys from 3472 nurses were completed anonymously. Univariate statistics were used to describe the study sample. One-way and multivariable Analysis of Variance were used to determine which variables contributed the most to job satisfaction. For about two thirds of the RNs, job satisfaction remained the same or had lessened over the past 2 years. In addition, statistically significant differences were found between job satisfaction and years of service, job position, hospital retirement plan, and geographic area. The findings have implications for nurse managers and hospital administrators for planning and implementing effective health policies that will meet the unique needs of their staffs and organizations. Such research is particularly relevant in this difficult time of nursing shortages throughout the healthcare industry.

  8. Forest soil erosion prediction as influenced by wildfire and roads

    Science.gov (United States)

    Cao, L.; Brooks, E. S.; Elliot, W.

    2017-12-01

    Following a wildfire, the risk of erosion is greatly increased. Forest road networks may change the underlying topography and alter natural flow paths. Flow accumulation and energy can be redistributed by roads and alter soil erosion processes. A LiDAR (Light Detection and Ranging) DEM makes it possible to quantify road topography, and estimate how roads influence surface runoff and sediment transport in a fire-disturbed watershed. With GIS technology and a soil erosion model, this study was carried out to evaluate the effect of roads on erosion and sediment yield following the Emerald Fire southwest of Lake Tahoe. The GeoWEPP model was used to estimate onsite erosion and offsite sediment delivery from each hillslope polygon and channel segment before and after fire disturbance in part of the burned area. The GeoWEPP flow path method was used to estimate the post-fire erosion rate of each GIS pixel. A 2-m resolution LiDAR DEM was used as the terrain layer. The Emerald Fire greatly increased onsite soil loss and sediment yields within the fire boundary. Following the fire, 78.71% of the burned area had predicted sediment yields greater than 4 Mg/ha/yr, compared to the preburn condition when 65.3% of the study area was estimated to generate a sediment yield less than 0.25 Mg/ha/yr. Roads had a remarkable influence on the flow path simulation and sub-catchments delineation, affecting sediment transport process spatially. Road segments acted as barriers that intercepted overland runoff and reduced downslope flow energy accumulation, therefore reducing onsite soil loss downslope of the road. Roads also changed the boundary of sub-catchment and defined new hydrological units. Road segments can transport sediment from one sub-catchment to another. This in turn leads to the redistribution of sediment and alters sediment yield for some sub-catchments. Culverts and road drain systems are of vital importance in rerouting runoff and sediment. Conservation structures can be

  9. Factors Influencing Acceptance Of Contraceptive Methods

    Directory of Open Access Journals (Sweden)

    Anita Gupta

    1997-04-01

    Full Text Available Research Problem: What are the factors influencing acceptance of contraceptive methods. Objective: To study the determinants influencing contra­ceptive acceptance. Study design: Population based cross - sectional study. Setting: Rural area of East Delhi. Participants: Married women in the reproductive age group. Sample:Stratified sampling technique was used to draw the sample. Sample Size: 328 married women of reproductive age group. Study Variables: Socio-economic status, Type of contraceptive, Family size, Male child. Outcome Variables: Acceptance of contraceptives Statistical Analysis: By proportions. Result: Prevalence of use of contraception at the time of data collection was 40.5%. Tubectomy and vasectomy were most commonly used methods. (59.4%, n - 133. Educational status of the women positively influenced the contraceptive acceptance but income did not. Desire for more children was single most important deterrent for accepting contraception. Recommendations: (i             Traditional method of contraception should be given more attention. (ii            Couplesshould be brought in the contraceptive use net at the early stage of marriage.

  10. Factors influencing tinnitus loudness and annoyance.

    Science.gov (United States)

    Hiller, Wolfgang; Goebel, Gerhard

    2006-12-01

    To evaluate the 2 major components of tinnitus severity, loudness and annoyance, and their degree of dependence on characteristics of tinnitus manifestation, history, and etiology. Cross-sectional survey performed during the first months of 2004. Nonclinical population. A total of 4995 members of the German Tinnitus League. Comprehensive screening questionnaire, including the Klockhoff and Lindblom loudness grading system and the miniversion of the Tinnitus Questionnaire. A moderate correlation of 0.45 was found between tinnitus loudness and annoyance. Both factors were generally higher in men, those older than 50 years, those with binaural and centrally perceived tinnitus, those with increased noise sensitivity, and those who had continuous tinnitus without interruptions. Tinnitus that lasted 12 months or less had a stronger influence on annoyance (odds ratio [OR], 1.96) than on loudness (OR, 0.45), whereas the contrary was found for tinnitus of more than 5 years' duration (ORs, 0.72 and 2.11, respectively). Loudness and annoyance were increased in subjects with coexisting hearing loss, vertigo, and hyperacusis. The impact of hyperacusis on annoyance was clearly stronger than on loudness (ORs, 21.91 vs 9.47). Several clinical factors of tinnitus influence perceived loudness and annoyance. Both are distinguishable components of tinnitus severity.

  11. Factors influencing endometrial thickness in postmenopausal women.

    Science.gov (United States)

    Hebbar, S; Chaya, V; Rai, L; Ramachandran, A

    2014-07-01

    Cut-off values for endometrial thickness (ET) in asymptomatic postmenopausal woman have been standardized. However, there are no comprehensive studies to document how various factors can influence the ET after the age of menopause. To study the various factors influencing the ET in postmenopausal women. This was a prospective observational study. A total of 110 postmenopausal women underwent detailed history taking, clinical examination, and transvaginal scan for uterine volume and ovarian volume. The volumes were calculated by using ellipsoid formula: Width × thickness × height × 0.523. The variation in ET with respect to the influencing factors such as age, duration of menopause, parity, body mass index (BMI), medical illness like diabetes/hypertension, drugs like tamoxifen, presence of myoma, uterine volume, ovarian volume, and serum estradiol (in selected patients) were measured. Descriptive analysis was performed using SPSS software (version 16, Chicago II, USA) to obtain mean, standard deviation (SD), 95% confidence intervals (CIs) and inter quartile ranges. Comparison of means was carried out using analysis of variance. The mean (SD) age of the patients was 55.4 (6.91) years (95% CI, 54.1, 56.7). The mean (SD) age at menopause was 47.95 (3.90) years (95% CI, 47.2, 48.7) and the mean (SD) duration of menopause was 7.27 (6.65) years (95% CI, 6.01, 8.53). The mean (SD) ET was 3.8 (2.3) mm (95% CI, 3.36, 4.23). Medical illness like diabetes and hypertension did not alter the ET. ET increased as BMI increased and it was statistically significant. The presence of myoma increased uterine volume significantly and was associated with thick endometrial stripe. Similarly, whenever the ovaries were visualized and as the ovarian volume increased, there was an increase in ET. When ET was > 4 mm (n = 37), they were offered endocel, of which 16 agreed to undergo the procedure. None were found to have endometrial cancer. This study suggests that parity, BMI, presence of

  12. Key-socio economic factors influencing sustainable land management investments in the West Usambara Highlands, Tanzania

    NARCIS (Netherlands)

    Nyanga, A.W.; Kessler, C.A.; Tenge, A.J.M.

    2016-01-01

    Low investments in sustainable land management (SLM) limit agricultural production in the East African Highlands, leading to increased soil erosion, low productivity of land and food insecurity. Recent studies in the region show that different socio-economic factors influence SLM investments by

  13. Influences of observation method, season, soil depth, land use and management practice on soil dissolvable organic carbon concentrations: A meta-analysis.

    Science.gov (United States)

    Li, Siqi; Zheng, Xunhua; Liu, Chunyan; Yao, Zhisheng; Zhang, Wei; Han, Shenghui

    2018-08-01

    Quantifications of soil dissolvable organic carbon concentrations, together with other relevant variables, are needed to understand the carbon biogeochemistry of terrestrial ecosystems. Soil dissolvable organic carbon can generally be grouped into two incomparable categories. One is soil extractable organic carbon (EOC), which is measured by extracting with an aqueous extractant (distilled water or a salt solution). The other is soil dissolved organic carbon (DOC), which is measured by sampling soil water using tension-free lysimeters or tension samplers. The influences of observation methods, natural factors and management practices on the measured concentrations, which ranged from 2.5-3970 (mean: 69) mg kg -1 of EOC and 0.4-200 (mean: 12) mg L -1 of DOC, were investigated through a meta-analysis. The observation methods (e.g., extractant, extractant-to-soil ratio and pre-treatment) had significant effects on EOC concentrations. The most significant divergence (approximately 109%) occurred especially at the extractant of potassium sulfate (K 2 SO 4 ) solutions compared to distilled water. As EOC concentrations were significantly different (approximately 47%) between non-cultivated and cultivated soils, they were more suitable than DOC concentrations for assessing the influence of land use on soil dissolvable organic carbon levels. While season did not significantly affect EOC concentrations, DOC concentrations showed significant differences (approximately 50%) in summer and autumn compared to spring. For management practices, applications of crop residues and nitrogen fertilizers showed positive effects (approximately 23% to 91%) on soil EOC concentrations, while tillage displayed negative effects (approximately -17%), compared to no straw, no nitrogen fertilizer and no tillage. Compared to no nitrogen, applications of synthetic nitrogen also appeared to significantly enhance DOC concentrations (approximately 32%). However, further studies are needed in the future

  14. Juvenile Southern Pine Response to Fertilization Is Influenced by Soil Drainage and Texture

    Directory of Open Access Journals (Sweden)

    Timothy J. Albaugh

    2015-08-01

    Full Text Available We examined three hypotheses in a nutrient dose and application frequency study installed in juvenile (aged 2–6 years old Pinus stands at 22 sites in the southeastern United States. At each site, eight or nine treatments were installed where nitrogen was applied at different rates (0, 67, 134, 268 kg ha−1 and frequencies (0, 1, 2, 4 and 6 years in two or four replications. Phosphorus was applied at 0.1 times the nitrogen rate and other elements were added as needed based on foliar nutrient analysis to insure that nutrient imbalances were not induced with treatment. Eight years after treatment initiation, the site responses were grouped based on texture and drainage characteristics: soil group 1 consisted of poorly drained soils with a clayey subsoil, group 2 consisted of poorly to excessively drained spodic soils or soils without a clay subsoil, and group 3 consisted of well-drained soils with a clayey subsoil. We accepted the first hypothesis that site would be a significant factor explaining growth responses. Soil group was also a significant factor explaining growth response. We accepted our second hypothesis that the volume growth-cumulative dose response function was not linear. Volume growth reached an asymptote in soil groups 1 and 3 between cumulative nitrogen doses of 300–400 kg ha−1. Volume growth responses continued to increase up to 800 kg ha−1 of cumulatively applied nitrogen for soil group 2. We accepted our third hypothesis that application rate and frequency did not influence the growth response when the cumulative nitrogen dose was equivalent. There was no difference in the growth response for comparisons where a cumulative nitrogen dose of 568 kg ha−1 was applied as 134 kg ha−1 every two years or as 269 kg ha−1 every four years, or where 269 kg ha−1 of nitrogen was applied as four applications of 67 kg ha−1 every two years or as two applications of 134 kg ha−1 every four years. Clearly, the sites examined

  15. Arbuscular mycorrhizal fungi and their influencing factors for aegiceras corniculatum and acanthus ilicifolius in southern china

    International Nuclear Information System (INIS)

    Hu, W.; Wu, Y.; Xin, G.

    2015-01-01

    Our study aimed to explore Arbuscular mycorrhizal fungi (AMF) colonization and spore density for Aegiceras corniculatum and Acanthus ilicifolius across five mangrove ecosystems in southern China, focusing mainly on the relationships between AMF and biotic/abiotic factors. Soil physicochemical properties and seawater salinity, as well as the numbers of culturable soil microbes (bacteria, fungi and actinmycetes) were measured to analyze their potential effects on AMF colonization. The results showed that AMF were very common for both plant species in the investigated mangrove ecosystems, and hyphae were the dominant structures for both species. Total AMF colonization rates (TC%) ranged from 0.33% to 36.50%, while the average TC% for A. ilicifolius (13.47%) was slightly higher than for A. corniculatum (9.47%). The average spore density for A. corniculatum was 49.0 spores per 25g air dried soil, and 51.7 for A. ilicifolius. Soil physicochemical analysis showed that soil in mangroves was with high moisture and organic matter content, slightly acidic pH, low levels of total and available P and high levels of N content. Microbial counting experiment recorded high microorganism numbers in mangroves. Data analysis revealed that soil available P content and seawater salinity may be important factors influencing AMF in mangroves. The two mangrove species showed different correlations with microbial numbers, which may illustrate that host plant is a key factor influencing AMF and other microbes. (author)

  16. Factors influencing career decisions in internal medicine.

    Science.gov (United States)

    Macdonald, C; Cawood, T

    2012-08-01

    Numerous factors influence career decisions for internal medicine trainees and Fellows. There is a perception that a greater emphasis is placed on work-family balance by younger physicians. To determine the characteristics of the modern internal medicine workforce and ascertain whether job flexibility is important to career decision-making. We hypothesised that factors which reflect flexibility would be highly influential in decision-making, especially for women and those with young children. A questionnaire was mailed to 250 New Zealand internal medicine trainees and Fellows. It focused on factors, including job flexibility, interest and collegial support, and included demographic details which were primarily aimed at ascertaining family responsibilities. Response rate was 54%. The majority of female physicians are the main person responsible for their children (62%), and the majority of their partners work full-time (80%). This contrasts with male physicians, of whom only 4% are the main person responsible for their children. Flexibility was found to be more influential in women, those with young children, trainees and those working in outpatient-based subspecialties. However, contrary to our original hypothesis, flexibility was not reported to be highly influential in any group, with career choice being most influenced by interest and enjoyment, intellectual challenge and variety within the job. It is hoped that results will inform employers and those involved with training to enable them to better cater for the needs of the workforce and also encourage trainees to consider future family commitments when making career decisions. © 2012 The Authors. Internal Medicine Journal © 2012 Royal Australasian College of Physicians.

  17. Food Offer Inside Agroecosystem Soils as an Ecological Factor for Settling Microhabitats by Soil Saprophagous Mites

    Directory of Open Access Journals (Sweden)

    Jaroslav Smrž

    2015-01-01

    Full Text Available Mainly abiotic factors have been considered in examining soil fauna invasion or settlement. The role of soil animals communities was not considered. Our hypothesis, indeed, can be formulated: the structure and feeding habits of the soil animals community is not able to play some role in the soil rating. Localities, however, can be fragmented into microhabitats. We studied cultivated field and adjacent unploughed areas (so-called baulks, using the common Berlese–Tullgren apparatus for community structure studies followed by histological tests of food consumed by community members. We selected a group of oribatid mites, which are frequent and abundant. In the studied localities and their microhabitats, three groups of oribatid mites can be reported. First – ubiquitous species a second – migrants from the less-impacted to more-impacted microhabitats and third – specialists sensitive to severe environmental conditions in more-impacted microhabitat. They consequently live only in the less-severe, less-impacted unploughed soils and never migrate from these microhabitats. Their grazed and digested food is more diversified, and they included more feeding specialists.

  18. Dependence of soil-to-plant transfer factors of elements on their concentrations in soil

    International Nuclear Information System (INIS)

    Tsukada, Hirofumi; Watabe, Teruhisa.

    1996-01-01

    Transfer factors (TFs) of 31 stable elements from soil to plant were determined by neutron activation analysis. Soil and plant samples were collected from 112 farm fields in Aomori prefecture, Japan. The elements described are those that could be detected by this method, which include essential elements for plant growth and nonessential elements. Several of these elements were divided into two groups, each having different TF characteristics. In the first group of elements there was an inverse correlation between the TFs and the soil concentrations of the elements, especially for Cl, K and Ca. The concentrations of these elements in plants were independent of their soil concentrations. However, in the second group, especially Sc and Co, the TFs were independent of the soil concentrations of the elements. The fluctuation of TFs observed in this study was smaller than that previously reported. This may be attributed to the relatively narrow geographic area of the present study. In addition, the TFs for the stable elements in this study were generally one to three orders of magnitude lower than those compiled for radioactive isotopes in previous publications. (author)

  19. The influence of organic matter on sorption and fate of glyphosate in soil - Comparing different soils and humic substances

    Energy Technology Data Exchange (ETDEWEB)

    Albers, Christian N., E-mail: calbers@ruc.d [Dept. of Geochemistry, Geological Survey of Denmark and Greenland, DK-1350 Copenhagen (Denmark); Dept. of Science, Systems and Models, Roskilde University, DK-4000 Roskilde (Denmark); Banta, Gary T. [Dept. of Environmental, Social and Spatial Change, Roskilde University, DK-4000 Roskilde (Denmark); Hansen, Poul Erik [Dept. of Science, Systems and Models, Roskilde University, DK-4000 Roskilde (Denmark); Jacobsen, Ole S. [Dept. of Geochemistry, Geological Survey of Denmark and Greenland, DK-1350 Copenhagen (Denmark)

    2009-10-15

    Soil organic matter (SOM) is generally believed not to influence the sorption of glyphosate in soil. To get a closer look on the dynamics between glyphosate and SOM, we used three approaches: I. Sorption studies with seven purified soil humic fractions showed that these could sorb glyphosate and that the aromatic content, possibly phenolic groups, seems to aid the sorption. II. Sorption studies with six whole soils and with SOM removed showed that several soil parameters including SOM are responsible for the strong sorption of glyphosate in soils. III. After an 80 day fate experiment, approx40% of the added glyphosate was associated with the humic and fulvic acid fractions in the sandy soils, while this was the case for only approx10% of the added glyphosate in the clayey soils. Glyphosate sorbed to humic substances in the natural soils seemed to be easier desorbed than glyphosate sorbed to amorphous Fe/Al-oxides. - Glyphosate was sorbed by purified humic substances and a significant amount of glyphosate was found to be associated with soil organic matter in whole soils.

  20. The influence of organic matter on sorption and fate of glyphosate in soil - Comparing different soils and humic substances

    International Nuclear Information System (INIS)

    Albers, Christian N.; Banta, Gary T.; Hansen, Poul Erik; Jacobsen, Ole S.

    2009-01-01

    Soil organic matter (SOM) is generally believed not to influence the sorption of glyphosate in soil. To get a closer look on the dynamics between glyphosate and SOM, we used three approaches: I. Sorption studies with seven purified soil humic fractions showed that these could sorb glyphosate and that the aromatic content, possibly phenolic groups, seems to aid the sorption. II. Sorption studies with six whole soils and with SOM removed showed that several soil parameters including SOM are responsible for the strong sorption of glyphosate in soils. III. After an 80 day fate experiment, ∼40% of the added glyphosate was associated with the humic and fulvic acid fractions in the sandy soils, while this was the case for only ∼10% of the added glyphosate in the clayey soils. Glyphosate sorbed to humic substances in the natural soils seemed to be easier desorbed than glyphosate sorbed to amorphous Fe/Al-oxides. - Glyphosate was sorbed by purified humic substances and a significant amount of glyphosate was found to be associated with soil organic matter in whole soils.

  1. FACTORS INFLUENCING FOOD NEOPHOBIA. A BRIEF REVIEW

    Directory of Open Access Journals (Sweden)

    STOICA Maricica

    2016-12-01

    Full Text Available Nowadays, the number of new food products has increased considerably. Nevertheless, not all new food products are accepted and understood by consumers, the innovations in the food sector are often not well received by the market, partly due to a phenomenon known as food neophobia. Food neophobia, a general aversion to try new or unfamiliar foods, has a major impact on preferences, selection and food product acceptability. The neophobic consumers tend to display negative attitudes and less pleasure in relation to new food products. Food neophobia is based on three main reasons for rejection of a food, such as: dislike of its sensory characteristics, fear of negative consequences of eating it, and disgust arising from the idea of the food’s nature or origin. Phobia towards the introduction of unfamiliar foods in the diet can occur for several different factors, such as: socio-demographic characteristics, education level and lifestyle, degree of urbanization, income level, arousal, personal experiences, advertising, fashion, advices of other persons, and habits. This review paper was designed to provide up-to-date relevant information on factors influencing food neophobia, like social factors, type of new food, education, and arousal. The scientific information presented here could help food scientists in new food development, and food companies to develop the best marketing strategies that lead to a general decrease in neophobic consumers’ behaviour. The application of appropriate marketing strategies may allow the product to reach a competitive advantage and be successful.

  2. Influence of organizational factors on performance reliability

    International Nuclear Information System (INIS)

    Haber, S.B.; O'Brien, J.N.; Metlay, D.S.; Crouch, D.A.

    1991-12-01

    This is the first volume of a two-volume report. Volume 2 will be published at a later date. This report presents the results of a research project conducted by Brookhaven National Laboratory for the United States Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. The purpose of the project was to develop a general methodology to be use in the assessment of the organizational factors which affect performance reliability (safety) in a nuclear power plant. The research described in this report includes the development of the Nuclear Organization and Management Analysis Concept (GNOMIC). This concept characterizes the organizational factors that impact safety performance in a nuclear power plant and identifies some methods for systematically measuring and analyzing the influence of these factors on safety performance. This report is divided into two parts; Part 1 presents an overview of the development of the methodology, while Part 2 provides more details and a technical analysis of the methodological development. Specifically, the results of two demonstration studies, the feasibility of the methodology, and a specific applications for which the methodology was developed are presented

  3. Evaluation of Factors Influencing Job Satisfaction

    Directory of Open Access Journals (Sweden)

    Barbara A. Sypniewska

    2014-03-01

    Full Text Available The term “job satisfaction” is derived from the humanities, psychology and sociology. In the field of psychology, it is a state where an employee has an emotional perception of his situation and reacts with feelings of pleasure or pain. In sociology, it is considered a variable in different categories related to how each employee evaluates and thinks about his work. Job satisfaction is closely related to the performance and quality of work performed by an employee and, consequently, translates into the success of an organization, because a satisfied employee builds and participates in the success of any organization. This article presents the results of the research conducted by the author in 2012 on a sample of 215 people. Respondents represented different organizations. The aim of the study was to identify and assess the significance of individual factors influencing satisfaction and dissatisfaction with work and demonstrate their impact on the overall assessment of job satisfaction. The study showed that between the weight attributed to individual factors and overall job satisfaction there are many statistically significant correlations referring mainly to selected on the basis of analysis respondents’ groups. The study confirms the raised thesis concerning the validity of research in the factors affecting the general feeling of satisfaction by the employees.

  4. Physiochemical Influence of Soil Minerals on the Organic Reduction of Soil Chromium

    International Nuclear Information System (INIS)

    Njoku, P.C.; Nweze, C.A.

    2009-01-01

    The physiochemical influence of soil minerals (Bentonite, Kaolinite, Diatomite,Rutile and Ferrihydrite) on the organic reduction ofchromium (VI) has been investigated with Oxalic acid as the organic reductant. The effect of pH and particle sizes of the soil minerals were also investigated. Results showed that with 0.1mol/dm3 concentration of Oxalic acid, the concentration of chromium(VI) remaining was 0.28, 0.34,0.38, 0.46 and 0.52mg/kgfor Bentonite, Rutile, Diatomite, Kaolinite and Ferrihydrite respectively whereas at 0.5mol/dm3of oxalic acid, the concentration of chromium reduced to 0.20,0.26, 0.30, 0.38, and0.44mg/kg for Bentonite, Rutile, Diatomite, Kaolinite and Ferrihydrite. Increasedconcentration of oxalic acid increased the reduction of chromium(VI) to chromium(III). At pH 5.0, the concentration of chromium(VI)left was 0.28, 0.34, 0.38,0.46 and 0.52mg/kg forBentonite, Rutile, Diatomite, Kaolinite and Ferrihydrite while at pH 2.5, concentration was0.16, 0.22, 0.26, 0.34 and 0.43mg/kg respectively. At particle size of 47-42 microns, concentration of chromium(VI) was 0.28, 0.34,0.38, 0.46, 0.52mg/kg for the same order ofthe soil minerals. At micron sizes of33-29 and 28-25 ranges the concentration ofchromium(VI) left was 0.23, 0.29, 0.33,0.41 and 0.47mg/kg for both micron sizes and corresponding minerals as well. These results showed that above 33-29 micron sizes, the influence of particle size was negligible. (author)

  5. Environmental and Geographical Factors Structure Soil Microbial Diversity in New Caledonian Ultramafic Substrates: A Metagenomic Approach.

    Directory of Open Access Journals (Sweden)

    Véronique Gourmelon

    Full Text Available Soil microorganisms play key roles in ecosystem functioning and are known to be influenced by biotic and abiotic factors, such as plant cover or edaphic parameters. New Caledonia, a biodiversity hotspot located in the southwest Pacific, is one-third covered by ultramafic substrates. These types of soils are notably characterised by low nutrient content and high heavy metal concentrations. Ultramafic outcrops harbour diverse vegetation types and remarkable plant diversity. In this study, we aimed to assess soil bacterial and fungal diversity in New Caledonian ultramafic substrates and to determine whether floristic composition, edaphic parameters and geographical factors affect this microbial diversity. Therefore, four plant formation types at two distinct sites were studied. These formations represent different stages in a potential chronosequence. Soil cores, according to a given sampling procedure, were collected to assess microbial diversity using a metagenomic approach, and to characterise the physico-chemical parameters. A botanical inventory was also performed. Our results indicated that microbial richness, composition and abundance were linked to the plant cover type and the dominant plant species. Furthermore, a large proportion of Ascomycota phylum (fungi, mostly in non-rainforest formations, and Planctomycetes phylum (bacteria in all formations were observed. Interestingly, such patterns could be indicators of past disturbances that occurred on different time scales. Furthermore, the bacteria and fungi were influenced by diverse edaphic parameters as well as by the interplay between these two soil communities. Another striking finding was the existence of a site effect. Differences in microbial communities between geographical locations may be explained by dispersal limitation in the context of the biogeographical island theory. In conclusion, each plant formation at each site possesses is own microbial community resulting from

  6. Influence of soil properties on the bioaccumulation and effects of arsenic in the earthworm Eisenia andrei

    NARCIS (Netherlands)

    Romero Freire, A.; Martin Peinado, F.J.; Diez Ortiz, M.; van Gestel, C.A.M.

    2015-01-01

    This study aimed at assessing the influence of soil properties on the uptake and toxicity effects of arsenic in the earthworm Eisenia andrei exposed for 4 weeks to seven natural soils spiked with different arsenic concentrations. Water-soluble soil concentrations (AsW) and internal As concentrations

  7. Influence of olive oil mill waste amendment on fate of oxyfluorfen in Southern Spain soils

    Science.gov (United States)

    The influence of olive oil mill waste (OOMW) amendment on soil processes affecting the herbicide oxyfluorfen (2-chloro-4-trifluoromethylphenyl-3-ethoxy-4-nitrophenyl ether) in two soils (P2 and SJ) was assessed under laboratory conditions. The soils used were from two diverse locations in Guadalqui...

  8. Effects of environmental factors and soil properties on topographic variations of soil respiration

    OpenAIRE

    Tamai, K.

    2010-01-01

    Soil respiration rates were measured along different parts of a slope in (a) an evergreen forest with common brown forest soil and (b) a deciduous forest with immature soil. The effects of soil temperature, soil moisture and soil properties were estimated individually, and the magnitudes of these effects in the deciduous and evergreen forests were compared. In the evergreen forest with common brown forest soil, soil properties had the greatest effect on soil respiration rates, followed by soi...

  9. Intrinsic and extrinsic factors influencing large African herbivore movements

    NARCIS (Netherlands)

    Venter, J.A.; Prins, H.H.T.; Mashanova, A.; Boer, de W.F.; Slotow, R.

    2015-01-01

    Understanding environmental as well as anthropogenic factors that influence large herbivore ecological patterns and processes should underpin their conservation and management. We assessed the influence of intrinsic, extrinsic environmental and extrinsic anthropogenic factors on movement behaviour

  10. Habitat factors influencing the distribution of Cymbopogon validus in ...

    African Journals Online (AJOL)

    Habitat factors influencing the distribution of Cymbopogon validus in Mkambati Game Reserve, Transkei. ... disturbance; game reserve; grassland; grasslands; habitat conditions; habitat factors; mkambati game ... AJOL African Journals Online.

  11. Relations between soil factors and herbage yields of natural ...

    African Journals Online (AJOL)

    Keywords: Cation exchange capacity; Correlation matrix; Nitrogen supplies; Root mass; Root measurements; Soil acidity; Soil variables; Soil water content; Soil water measurements; Yield measurements; nitrogen supply; ph; herbage yield; grassland; soils; productivity; soil depth; dry matter yield; grasses; water content; n; ...

  12. Influence of Root Exudates and Soil on Attachment of Pasteuria penetrans to Meloidogyne arenaria.

    Science.gov (United States)

    Liu, Chang; Timper, Patricia; Ji, Pingsheng; Mekete, Tesfamariam; Joseph, Soumi

    2017-09-01

    The bacterium Pasteuria penetrans is a parasite of root-knot nematodes ( Meloidogyne spp.). Endospores of P. penetrans attach to the cuticle of second-stage juveniles (J2) and subsequently sterilize infected females. When encumbered by large numbers of spores, juveniles are less mobile and their ability to infect roots is reduced. This study looked at different factors that influence spore attachment of P. penetrans to the root-knot nematode Meloidogyne arenaria . Pretreatment of J2 with root exudates of eggplant ( Solanum melongena cv. Black beauty) reduced spore attachment compared with pretreatment with phosphate-buffered saline (PBS), suggesting that the nematode surface coat was altered or the spore recognition domains on the nematode surface were blocked. Spore attachment was equally reduced following exposure to root exudates from both host and nonhost plants for M. arenaria , indicating a common signal that affects spore attachment. Although phytohormones have been shown to influence the lipophilicity of the nematode surface coat, auxins and kinetins did not affect spore attachment compared with PBS. Root exudates reduced spore attachment more in sterilized soil than in natural soil. Sterilization may have eliminated microbes that consume root exudates, or altered the chemical components of the soil solution or root exudates. Root exudates caused a greater decrease in spore attachment in loamy sand than in a sandy loam soil. The sandy loam had higher clay content than the loamy sand, which may have resulted in more adsorption of compounds in the root exudates that affect spore attachment. The components of the root exudates could have also been modified by soil type. The results of this study demonstrate that root exudates can decrease the attachment of P. penetrans endospores to root-knot nematodes, indicating that when these nematodes enter the root zone their susceptibility to spore attachment may decrease.

  13. Spatially explicit analysis of metal transfer to biota: influence of soil contamination and landscape.

    Directory of Open Access Journals (Sweden)

    Clémentine Fritsch

    Full Text Available Concepts and developments for a new field in ecotoxicology, referred to as "landscape ecotoxicology," were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessment. The aim of this study was to investigate the spatial heterogeneity of metal bioaccumulation in animals in order to identify the role of spatially explicit factors, such as landscape as well as total and extractable metal concentrations in soils. Over a smelter-impacted area, we studied the accumulation of trace metals (TMs: Cd, Pb and Zn in invertebrates (the grove snail Cepaea sp and the glass snail Oxychilus draparnaudi and vertebrates (the bank vole Myodes glareolus and the greater white-toothed shrew Crocidura russula. Total and CaCl(2-extractable concentrations of TMs were measured in soils from woody patches where the animals were captured. TM concentrations in animals exhibited a high spatial heterogeneity. They increased with soil pollution and were better explained by total rather than CaCl(2-extractable TM concentrations, except in Cepaea sp. TM levels in animals and their variations along the pollution gradient were modulated by the landscape, and this influence was species and metal specific. Median soil metal concentrations (predicted by universal kriging were calculated in buffers of increasing size and were related to bioaccumulation. The spatial scale at which TM concentrations in animals and soils showed the strongest correlations varied between metals, species and landscapes. The potential underlying mechanisms of landscape influence (community functioning, behaviour, etc. are discussed. Present results highlight the need for the further development of landscape ecotoxicology and multi-scale approaches, which would enhance our

  14. [Bioavailability and factors influencing its rate].

    Science.gov (United States)

    Vraníková, Barbora; Gajdziok, Jan

    Bioavailability can be defined as the rate and range of active ingredient absorption, when it becomes available in the systemic circulation or at the desired site of drug action, respectively. Drug bioavailability after oral administration is affected by anumber of different factors, including physicochemical properties of the drug, physiological aspects, the type of dosage form, food intake, biorhythms, and intra- and interindividual variability of the human population. This article is the first from the series dealing with the bioavailability and methods leading to its improvement. The aim of the present paper is to provide an overview of aspects influencing the rate of bioavailability after oral administration of the active ingredient. Subsequentarticles will provide detailed descriptions of methods used for dug bioavailability improvement, which are here only summarized.

  15. Factors influencing initiation of breast-feeding.

    Science.gov (United States)

    Ekwo, E E; Dusdieker, L B; Booth, B M

    1983-04-01

    We used the critical incidence method to study factors motivating 33 primigravidas and 39 multigravidas to initiate breast-feeding of their infants. Women chose breast-feeding because they believed that it would provide protection to the infant against infection, establish maternal-infant bonding, was convenient, provided better nutrition than cow's milk formula, was emotionally satisfying, and was the natural way to feed infants. The decision to breast-feed was made well in advance of pregnancy by primigravidas and shortly before pregnancy by multigravidas. Friends who had successfully nursed infants were as influential as immediate family members in influencing our study subjects in their decision to breast-feed. Prenatal counseling, though important, may not be the optimal period for motivating women to breast-feed.

  16. Factors influencing presence in virtual worlds.

    Science.gov (United States)

    Chow, Meyrick C M

    2012-01-01

    Virtual worlds are showing potential as an effective platform for a variety of activities, including learning. The concept of presence (the sensation of "being there" in a mediated environment) has received substantial attention from the virtual reality community, and the effectiveness of virtual worlds has often been linked to the feelings of presence reported by their users. The present study examined the effects of attitude and perceived ease of use on sense of presence in Second Life, which is one of the most known and used virtual worlds. Based on data from a survey of 206 nursing students, hypotheses are empirically tested. Findings suggest that users' attitude toward using Second Life and their perceived ease of use of it have a positive effect on their sense of presence in the virtual environment. This study advances our understanding of factors influencing presence in virtual worlds.

  17. FACTORS INFLUENCING THE MANAGEMENT OF ADHD

    Directory of Open Access Journals (Sweden)

    S ARMAN

    2003-03-01

    Full Text Available Introduction: Attention deficit hyperactivity disorder (ADHDis the most common psychiatric disorder among school age children. It consists of hyperactivity, inattention and impulsive behavior. The onset of the disorder is before the age of 7 years and it happens at least in two situations. It causes significant impairment in social and academic functioning. A determination of factors that influences the therapeutic response in ADHD is the aim of this study. Methods: This study is designed as an analytic descriptive on hyperactive children. The tools that were used was the interview with parents and it provided CSI-4 checklist. Results: Methylphenidate was completely effective in ADHD and oppositional defiant disorder and was effective in majority sign of conduct disorder. There wasn't any relation between therapeutic response and demographic characteristics. Discussion: Methylphenidate is effective not only in ADHD but also in mixed ADHD and disruptive behavior.

  18. Factors influencing consumer dietary health preventative behaviours.

    Science.gov (United States)

    Petrovici, Dan A; Ritson, Christopher

    2006-09-01

    The deterioration of the health status of the Romanian population during the economic transition from a centrally planned to a free market economy has been linked to lifestyles factors (e.g. diet) regarded as a main determinants of the disparity in life expectancy between Eastern and Western Europe. Reforms in the health care system in this transition economy aim to focus on preventive action. The purpose of this study was to identify the factors that impact on the individual decision to engage in Dietary Health Preventive Behaviour (DHPB) and investigate their influence in the context of an adapted health cognition model. A population-based study recruited 485 adult respondents using random route sampling and face-to-face administered questionnaires. Respondents' health motivation, beliefs that diet can prevent disease, knowledge about nutrition, level of education attainment and age have a positive influence on DHPB. Perceived barriers to healthy eating have a negative impact on alcohol moderation. The information acquisition behaviour (frequency of reading food labels) is negatively predicted by age and positively predicted by health motivation, education, self-reported knowledge about nutrition and household financial status. A significant segment of respondents believe they are not susceptible to the elicited diseases. Health promotion strategies should aim to change the judgments of health risk. The adaptation of the Health Belief Model and the Theory of Health Preventive Behaviour represents a valid framework of predicting DHPB. The negative sign of perceived threat of disease on DHPB may suggest that, under an income constraint, consumers tend to trade off long-term health benefits for short-term benefits. This cautions against the use of negative messages in public health campaigns. Raising the awareness of diet-disease relationships, knowledge about nutrition (particularly sources and risks associated with dietary fat and cholesterol) may induce people to

  19. Geochemical factors influencing vault design and layout

    International Nuclear Information System (INIS)

    Gascoyne, M.; Stroes-Gascoyne, S.; Sargent, F.P.

    1995-01-01

    The design and construction of a vault for used nuclear fuel in crystalline rock may be influenced by a number of geochemical factors. During the siting stage, information is needed regarding the rock type, heterogeneities in its composition and the mineralogy of permeable zones because these will cause variations in thermal conductivity, strength and radionuclide sorptive properties of the rock. These factors may affect decisions regarding depth of vault construction, tunnel dimensions and spacing of panels and waste containers. The decision on whether groundwaters are allowed to flow freely into a planned excavation may depend on measurements of their chemical compositions, microbiological contents and presence of hazardous or corrosive constituents. During site characterization, borehole drilling from the surface and subsequent hydraulic testing will introduce both chemical and microbiological contaminants that may further influence this decision. During vault construction, the geochemistry of the rock may cause changes to the characterization, design and construction of the vault. For example, high salinity fluids in micropores in the rock could prevent the use of radar surveys to detect fractures in the surrounding rock. High rock salinity may also cause unacceptably high total dissolved solids loadings in water discharged from the facility. Again, the presence of toxic, corrosive or radioactive constituents in inflowing groundwater may require grouting or, if inflow is needed for service operations, development of treatment facilities both above and below ground. In addition, the use of explosives will cause high organic and nitrate loadings in service water as well as the possible impregnation of these chemicals in the damaged wall-rock surrounding an excavation. These chemicals may remain despite cleaning efforts and act as nutrients to promote microbial activity in the post-closure phase. In the operational phase, further design and construction, changes

  20. Factors influencing consumer dietary health preventative behaviours

    Directory of Open Access Journals (Sweden)

    Ritson Christopher

    2006-09-01

    Full Text Available Abstract Background The deterioration of the health status of the Romanian population during the economic transition from a centrally planned to a free market economy has been linked to lifestyles factors (e.g. diet regarded as a main determinants of the disparity in life expectancy between Eastern and Western Europe. Reforms in the health care system in this transition economy aim to focus on preventive action. The purpose of this study was to identify the factors that impact on the individual decision to engage in Dietary Health Preventive Behaviour (DHPB and investigate their influence in the context of an adapted health cognition model. Methods A population-based study recruited 485 adult respondents using random route sampling and face-to-face administered questionnaires. Results and discussion Respondents' health motivation, beliefs that diet can prevent disease, knowledge about nutrition, level of education attainment and age have a positive influence on DHPB. Perceived barriers to healthy eating have a negative impact on alcohol moderation. The information acquisition behaviour (frequency of reading food labels is negatively predicted by age and positively predicted by health motivation, education, self-reported knowledge about nutrition and household financial status. A significant segment of respondents believe they are not susceptible to the elicited diseases. Health promotion strategies should aim to change the judgments of health risk. Conclusion The adaptation of the Health Belief Model and the Theory of Health Preventive Behaviour represents a valid framework of predicting DHPB. The negative sign of perceived threat of disease on DHPB may suggest that, under an income constraint, consumers tend to trade off long-term health benefits for short-term benefits. This cautions against the use of negative messages in public health campaigns. Raising the awareness of diet-disease relationships, knowledge about nutrition (particularly

  1. Influence of agrochemical characteristics of 85Sr and 137Cs in soil samples from the localities around nuclear power plants in Slovak Republic

    International Nuclear Information System (INIS)

    Cipakova, A.; Mitro, A.

    1997-01-01

    Sorption of radiostrontium and radiocesium, two biologically available radionuclides in soils was studied. Experiments were carried out on the soil samples from the localities around nuclear power plants. Adsorption processes are the function of many factors. Multi-para-metrical regression analysis was used for studying of the influence of agrochemical characteristics on sorption of 85 Sr and 137 Cs in observed soil types. (authors)

  2. Sorption of Cu and Zn in low organic matter-soils as influenced by soil properties and by the degree of soil weathering.

    Science.gov (United States)

    Antoniadis, V; Golia, E E

    2015-11-01

    Copper and Zn sorption and desorption, among other factors, depend on soil pH, but in soils with different degree of weathering the role of other soil properties (e.g., oxides content and the level of their crystallinity) has not been thoroughly examined. We conducted batch sorption and desorption tests using 21 low-organic C soils that belonged to the soil orders of Entisols, newly developed soils, Inceptisols, and Alfisols, the most weathered soils. Zinc sorption was lower than that of Cu, and its desorption faster, confirming that it is a highly mobile metal. Alfisols had the weaker affinity for metals, due to the lower soil pH typical of this soil order, but also due to the low reactivity colloids they contained. Correlation analyses showed that Fe oxides in Alfisols increased metal release from soils, while they decreased metal desorption from Entisols. We conclude that in low organic matter-content soils, where the protective role of organic colloids is not to be expected, high soil pH alone is not sufficient to protect against metal contamination, but the degree of soil weathering is also important, due to the dominant role of other mineral phases (here, Fe oxides). Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Characterization and nutrient release from silicate rocks and influence on chemical changes in soil

    Directory of Open Access Journals (Sweden)

    Douglas Ramos Guelfi Silva

    2012-06-01

    Full Text Available The expansion of Brazilian agriculture has led to a heavy dependence on imported fertilizers to ensure the supply of the growing food demand. This fact has contributed to a growing interest in alternative nutrient sources, such as ground silicate rocks. It is necessary, however, to know the potential of nutrient release and changes these materials can cause in soils. The purpose of this study was to characterize six silicate rocks and evaluate their effects on the chemical properties of treated soil, assessed by chemical extractants after greenhouse incubation. The experimental design consisted of completely randomized plots, in a 3 x 6 factorial scheme, with four replications. The factors were potassium levels (0-control: without silicate rock application; 200; 400; 600 kg ha-1 of K2O, supplied as six silicate rock types (breccia, biotite schist, ultramafic rock, phlogopite schist and two types of mining waste. The chemical, physical and mineralogical properties of the alternative rock fertilizers were characterized. Treatments were applied to a dystrophic Red-Yellow Oxisol (Ferralsol, which was incubated for 100 days, at 70 % (w/w moisture in 3.7 kg/pots. The soil was evaluated for pH; calcium and magnesium were extracted with KCl 1 mol L-1; potassium, phosphorus and sodium by Mehlich 1; nickel, copper and zinc with DTPA; and the saturation of the cation exchange capacity was calculated for aluminum, calcium, magnesium, potassium, and sodium, and overall base saturation. The alternative fertilizers affected soil chemical properties. Ultramafic rock and Chapada mining byproduct (CMB were the silicate rocks that most influenced soil pH, while the mining byproduct (MB led to high K levels. Zinc availability was highest in the treatments with mining byproduct and Cu in soil fertilized with Chapada and mining byproduct.

  4. CS-137 transfer factors soil-plant and density of hyphae in soil of spruce forests

    International Nuclear Information System (INIS)

    Klemt, E.; Deuss, H.; Drissner, J.; Krapf, M.; Miller, R.; Zibold, G.

    1999-01-01

    Samples of soil and plants were taken at spruce stand sites in southern Baden-Wuerttemberg. Fern always had the highest aggregated Cs-137 transfer factor (T ag ) varying between 0.01 and 0.27 m 2 kg -1 . There is a tendency for higher T ag s in soils with thicker raw humus layers, lower pH, lower cation exchange capacity (CEC) in the O h horizon, and lower clay content below the organic deposit. The density of hyphae is determined by the season and its weather conditions and it usually decreases continuously from O f to top B horizon. In analyzing our data no correlation between aggregated or horizon-specific transfer factors of different plants and density of hyphae could be found. Refs. 5 (author)

  5. Factors influencing choice of oral hygiene products by dental ...

    African Journals Online (AJOL)

    Background: Several factors, such as cost, branding, packaging and family influence, had been implicated as influencing the choice of toothpastes and toothbrushes by individuals. Media advertisement is also considered a very strong factor influencing consumer's choice. Aim: To assess the extent to which some factors ...

  6. Evaluation of coal combustion byproducts as soil liming materials - their influence on soil pH and enzyme activities

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, G W; Siddaramappa, R; Wright, R J; Codling, E E; Gao, G

    1994-03-01

    To evaluate coal combustion byproducts as liming materials and address issues related to soil quality, the authors compared the influence of different amounts of four combustion byproducts (fly ash and bed ash from a fluidized bed combustion furnace, lime-injected multistage burner residue, and spray dryer residue) and CaCO[sub 3] on soil pH and activities of urease, phosphatase, arylsulfatase, and dehydrogenase in an acidic soil. Studies comparing the influence of the combustion byproducts and CaCO[sub 3] on soil pH showed that on weight basis of application, substantial differences were observed in the ability of these materials to influence soil pH but that such differences decreased markedly after the data were transformed to a CaCO[sub 3] equivalent basis of application. Analysis of covariance for these transformed data indicated that whereas the liming abilities of fly ash and CaCO[sub 3] were not significantly different when compared on the CaCO[sub 3] equivalent basis, those of bed ash, multistage burner residue, and spray dryer residue were less than that of CaCO[sub 3]. Studies comparing the influence of the byproducts and CaCO[sub 3] on soil enzyme activities showed that the effect of these liming materials on the enzyme activities studied was largely due to their influence on soil pH. These studies showed that the combustion byproducts tested functioned as soil liming materials in a manner similar to that of CaCO[sub 3] and seemed to have little adverse effect on soil quality.

  7. Factors Influencing Students’ Perceptions of Online Teamwork

    Directory of Open Access Journals (Sweden)

    Irina Falls

    2014-02-01

    Full Text Available The evolution of online teaching in higher education demands a change in the types of pedagogies used in those courses. An example of one of these important pedagogies includes online teamwork. Teamwork in this context is one in which the majority of the individual’s grade is dependent on the positive or negative group experiences. This study utilized the theoretical framework of social motivation and cohesion to identify the factors shaping students’ perceptions of teamwork in online college courses. In these courses, the pedagogical approach known as the Five Pillars of effective collaborative work was applied. An Online Teamwork Learning Survey was developed based on these principles and completed by 62 undergraduate students enrolled in semester-long online courses required in their early childhood education program of study. Using a comparison between pre–postsurveys and regression analysis, the results showed that although the students’ perceptions of teamwork did not significantly change, the factors influencing their responses during the posttest doubled in number. The results showed that through carefully designed virtual teamwork activities, students learned that essential team characteristics such as promotive interaction, individual accountability, and positive interdependence are an integral part of effective collaboration and strong predictors of teamwork perception.

  8. Factors Influencing Teamwork in Health Care

    Directory of Open Access Journals (Sweden)

    Mijal Michał

    2017-06-01

    Full Text Available The purpose of this paper is to analyse different views on interpersonal relations and team composition among managers and medical professionals with respect to the transition of professional roles in healthcare in Poland. To achieve that goal, a description based on a quantitative and qualitative questionnaire was conducted. Since the questionnaire covered various areas of health care, only its small fraction was used for the analysis. The main result is that most of the medical professionals and medical managers consider technology to be the single most important external factor influencing the team work efficiency and team composition in health care, and the managers consider skillset as the crucial factor determining whether a person would be a good team member. Based on the literature on professional roles in health care and their evolution in recent years, one can assume that constant development and lifelong learning would play a significant role in the healthcare systems reform. The findings are an important contribution to the discussion of the healthcare reform and its possible directions in future years as well a reference point for policy makers.

  9. Factors influencing performance within startup assistance organizations

    Directory of Open Access Journals (Sweden)

    Ceaușu Ioana

    2017-07-01

    Full Text Available Startup assistance organizations, and especially business accelerators have gained a lot of traction in the last years, captioning not only the attention of the public, but most importantly that of investors and other stakeholders. It has become a challenge for many all around the world to develop such programs, but many have failed or did not have their expected results, meaning medium to long-term sustainable and profitable alumni start-ups. As high amounts of resources, both human and financial, are being invested in the design and development of such programs, it is important to understand what sets apart the successful business acceleration programs from the ones that fail. The current paper is reviewing the up-to-date theoretical literature and studies on the matter at hand, in order to identify the most relevant factors influencing startup assistance organizations’ performance. The objective behind identifying these factors is to get a better understanding of best practices of such successful programs and set the basis for future research regarding the development of a set of metrics for more accurately measuring their performance.

  10. A preliminary evaluation of some soil and plant parameters that influence root uptake of arsenic, cadmium, cooper, and zinc

    International Nuclear Information System (INIS)

    Hattemer-Frey, H.A.; Krieger, G.R.; Lau, V.

    1994-01-01

    In the absence of site-specific data, the concentration of metals in plants is typically estimated by multiplying the total concentration of metal in soil by a metal-specific soil-to-root bioconcentration factor (BCF). However, this approach does not account for various soil properties, such as pH, organic matter content, and cation exchange capacity, that are known to influence root uptake of some metals. For risk assessment purposes, a simple, predictive method for estimating root uptake of metals that is based on site-specific soil and crop data is needed so that the importance of the produce ingestion pathway and subsequent influence on human exposure can be quantitatively assessed. An easy-to-use method is necessary since collecting site-specific data on the concentration of metals in home-grown produce is often time-consuming and costly. Ideally, it should be possible to develop a statistically-reliable relationship between plant and soil metals levels that includes appropriate weighing factors for various soil properties. Multiple linear regression analyses were used to develop simple, predictive models for estimating the concentration of metals in plants via root uptake using site-specific soil data. This paper presents preliminary predictive equations for estimating root uptake of arsenic, cadmium, copper, and zinc in fruiting, root, and all vegetables combined (i.e., fruiting and root crop data were combined). Results show that by using data on additional soil parameters (other than relying solely on the concentration of metals in soil), the concentration of metals in fruiting and root vegetables can be more confidently predicted

  11. Potential microbial risk factors related to soil amendments and irrigation water of potato crops.

    Science.gov (United States)

    Selma, M V; Allende, A; López-Gálvez, F; Elizaquível, P; Aznar, R; Gil, M I

    2007-12-01

    This study assesses the potential microbial risk factors related to the use of soil amendments and irrigation water on potato crops, cultivated in one traditional and two intensive farms during two harvest seasons. The natural microbiota and potentially pathogenic micro-organisms were evaluated in the soil amendment, irrigation water, soil and produce. Uncomposted amendments and residual and creek water samples showed the highest microbial counts. The microbial load of potatoes harvested in spring was similar among the tested farms despite the diverse microbial levels of Listeria spp. and faecal coliforms in the potential risk sources. However, differences in total coliform load of potato were found between farms cultivated in the autumn. Immunochromatographic rapid tests and the BAM's reference method (Bacteriological Analytical Manual; AOAC International) were used to detect Escherichia coli O157:H7 from the potential risk sources and produce. Confirmation of the positive results by polymerase chain reaction procedures showed that the immunochromatographic assay was not reliable as it led to false-positive results. The potentially pathogenic micro-organisms of soil amendment, irrigation water and soil samples changed with the harvest seasons and the use of different agricultural practices. However, the microbial load of the produce was not always influenced by these risk sources. Improvements in environmental sample preparation are needed to avoid interferences in the use of immunochromatographic rapid tests. The potential microbial risk sources of fresh produce should be regularly controlled using reliable detection methods to guarantee their microbial safety.

  12. Preoperative factors influencing success in pterygium surgery.

    Science.gov (United States)

    Torres-Gimeno, Ana; Martínez-Costa, Lucía; Ayala, Guillermo

    2012-08-08

    To identify preoperative, perioperative and postoperative risk factors that influence the success of pterygium surgery. This is a prospective study of thirty-six patients with primary or recurrent pterygia. A detailed anamnesis and an ophthalmological examination were performed looking for the following factors: age, race, latitude and altitude of the main place of residence, hours of exposure to the sun, use of protective measures against UV-radiation, classification of pterygium, width of the pterygium at limbus, surgical technique (conjunctival autograft plus suturing versus tissue glue), graft alterations (misapposition, granuloma, haemorrhage, oedema, retraction or necrosis), and postoperative symptoms (foreign-body sensation, pain). The examinations were performed 2 and 7 days and 2, 6 and 12 months after surgery. In addition, recurrence was defined as any growth of conjunctiva into the cornea. A logistic regression and a survival analysis have been used to perform data analysis. A total number of 36 patients completed a one year follow-up. A total of 13 patients were born and lived in Spain, and 26 came from other countries, mostly Latin America. A total number of 8 males (no women) presented a recurrence, mainly between 2 and 6 months. The hours of sun exposure through their life was independently related to surgical success. Pterygia of less than 5 mm of base width showed a weak positive correlation with recurrence. None of the other factors considered were significantly related to recurrence. Male gender and high sun exposure are strongly and independently related to surgical success after the removal of pterygia.

  13. Preoperative factors influencing success in pterygium surgery

    Directory of Open Access Journals (Sweden)

    Torres-Gimeno Ana

    2012-08-01

    Full Text Available Abstract Background To identify preoperative, perioperative and postoperative risk factors that influence the success of pterygium surgery. Methods This is a prospective study of thirty-six patients with primary or recurrent pterygia. A detailed anamnesis and an ophthalmological examination were performed looking for the following factors: age, race, latitude and altitude of the main place of residence, hours of exposure to the sun, use of protective measures against UV-radiation, classification of pterygium, width of the pterygium at limbus, surgical technique (conjunctival autograft plus suturing versus tissue glue, graft alterations (misapposition, granuloma, haemorrhage, oedema, retraction or necrosis, and postoperative symptoms (foreign-body sensation, pain. The examinations were performed 2 and 7 days and 2, 6 and 12 months after surgery. In addition, recurrence was defined as any growth of conjunctiva into the cornea. Results A logistic regression and a survival analysis have been used to perform data analysis. A total number of 36 patients completed a one year follow-up. A total of 13 patients were born and lived in Spain, and 26 came from other countries, mostly Latin America. A total number of 8 males (no women presented a recurrence, mainly between 2 and 6 months. The hours of sun exposure through their life was independently related to surgical success. Pterygia of less than 5 mm of base width showed a weak positive correlation with recurrence. None of the other factors considered were significantly related to recurrence. Conclusions Male gender and high sun exposure are strongly and independently related to surgical success after the removal of pterygia.

  14. Atmospheric dust additions as a soil formation factor

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Hernandez, J. L.; Ruoss, J.

    2009-07-01

    The Mediterranean area is distinguished by a least four features that determine the nature of its soils. These are its climate, its mountains, the addition of exogenous dust and ongoing anthropogenic effects. We here present three cases in which the influence of atmospheric dust additions can be detected in the soils of representative circum-Saharan contexts the Canary Islands, Betic intramontane depressions, and the Sierra Bermeja peridotite massif (Malaga). The unique position of the Canary Islands determines important rates of dust deposit, largely depending on position on the relief. the nature of the dust contrasts with the rocky substratum of the islands, and the marine and volcanic context can also affect the nature of the deposits. The numerous, extensive intramontane basins of the Betic Cordilleras act as large captors of atmospheric dust, with rates similar to those found in the Canary archipelago. The carbonate content of these exogenous additions represents a significant components that should be taken into account when establishing the carbonate accumulation regime in these soils. (Author) 13 refs.

  15. The influence of tree species composition on the storage and mobility of semivolatile organic compounds in forest soils

    Energy Technology Data Exchange (ETDEWEB)

    Komprdová, Klára, E-mail: komprdova@recetox.muni.cz [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Komprda, Jiří [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Menšík, Ladislav [Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 3, Brno 613 00 (Czech Republic); Vaňková, Lenka [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Kulhavý, Jiří [Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 3, Brno 613 00 (Czech Republic); Nizzetto, Luca [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Norwegian Institute for Water Research, Gaustadalleen 21, NO-0349 Oslo (Norway)

    2016-05-15

    Soil contamination with PCBs and PAHs in adjacent forest plots, characterized by a distinct composition in tree species (spruce only, mixed and beech only), was analyzed to investigate the influence of ecosystem type on contaminant mobility in soil under very similar climate and exposure conditions. Physical-chemical properties and contaminant concentrations in litter (L), organic (F, H) and mineral (A, B) soil horizons were analyzed. Contaminant distribution in the soil core varied both in relation to forest type and contaminant group/properties. Contaminant mobility in soil was assessed by examining the ratios of total organic carbon (TOC)-standardized concentrations across soil horizons (Enrichment factors, EF{sub TOC}) and the relationship between EF{sub TOC} and the octanol-water equilibrium partitioning coefficient (K{sub OW}). Contaminant distribution appeared to be highly unsteady, with pedogenic/biogeochemical drivers controlling contaminant mobility in organic layers and leaching controlling accumulation in mineral layers. Lighter PCBs displayed higher mobility in all forest types primarily controlled by leaching and, to a minor extent, diffusion. Pedogenic processes controlling the formation of soil horizons were found to be crucial drivers of PAHs and heavier PCBs distribution. All contaminants appeared to be more mobile in the soil of the broadleaved plot, followed by mixed canopy and spruce forest. Increasing proportion of deciduous broadleaf species in the forest can thus lead to faster degradation or the faster leaching of PAHs and PCBs. The composition of humic substances was found to be a better descriptor of contaminant concentration than TOC. - Highlights: • Tree species composition influences vertical distribution of PCBs and PAHs in soils. • PCBs and PAHs were more mobile in the soil of the broadleaved plot. • Low molecular weight PCBs displayed higher mobility in all forest types. • Humic substances were important descriptors of

  16. The influence of tree species composition on the storage and mobility of semivolatile organic compounds in forest soils

    International Nuclear Information System (INIS)

    Komprdová, Klára; Komprda, Jiří; Menšík, Ladislav; Vaňková, Lenka; Kulhavý, Jiří; Nizzetto, Luca

    2016-01-01

    Soil contamination with PCBs and PAHs in adjacent forest plots, characterized by a distinct composition in tree species (spruce only, mixed and beech only), was analyzed to investigate the influence of ecosystem type on contaminant mobility in soil under very similar climate and exposure conditions. Physical-chemical properties and contaminant concentrations in litter (L), organic (F, H) and mineral (A, B) soil horizons were analyzed. Contaminant distribution in the soil core varied both in relation to forest type and contaminant group/properties. Contaminant mobility in soil was assessed by examining the ratios of total organic carbon (TOC)-standardized concentrations across soil horizons (Enrichment factors, EF_T_O_C) and the relationship between EF_T_O_C and the octanol-water equilibrium partitioning coefficient (K_O_W). Contaminant distribution appeared to be highly unsteady, with pedogenic/biogeochemical drivers controlling contaminant mobility in organic layers and leaching controlling accumulation in mineral layers. Lighter PCBs displayed higher mobility in all forest types primarily controlled by leaching and, to a minor extent, diffusion. Pedogenic processes controlling the formation of soil horizons were found to be crucial drivers of PAHs and heavier PCBs distribution. All contaminants appeared to be more mobile in the soil of the broadleaved plot, followed by mixed canopy and spruce forest. Increasing proportion of deciduous broadleaf species in the forest can thus lead to faster degradation or the faster leaching of PAHs and PCBs. The composition of humic substances was found to be a better descriptor of contaminant concentration than TOC. - Highlights: • Tree species composition influences vertical distribution of PCBs and PAHs in soils. • PCBs and PAHs were more mobile in the soil of the broadleaved plot. • Low molecular weight PCBs displayed higher mobility in all forest types. • Humic substances were important descriptors of contaminant

  17. Factors responsible for the patchy distribution of natural soil water repellency in Mediterranean semiarid forest

    Science.gov (United States)

    Lozano, E.; Jiménez-Pinilla, P.; Mataix-Solera, J.; González-Pérez, J. A.; García-Orenes, F.; Torres, M. P.; Arcenegui, V.; Mataix-Beneyto, J.

    2012-04-01

    H and between SOM and pH for all except for Q. rotundifolia. However, the negative correlation found between pH and persistence of WR seems to be related to soil organic matter (SOM) content for all vegetal species. Glomalin exudates from arbuscular mycorrhizal fungi in soil revealed significant differences between species. However, the first results do not point to a direct relationship between EEG content and WR but to soil mineralogy or certain components within SOM pool i.e. litter debris degradation products or specific components within the glomalin extract, as main factors affecting soil WR. Nonetheless, since some samples with the same SOM content (including some under the same vegetation cover) showed different WR persistence, complementary research including a more detailed characterization of most soil functional fractions (SOM and clays) is planned in order to elucidat the main factors influencing the presence and persistence of WR in soils under Mediterranean semiarid forest. Keywords: Water repellency, hydrophobicity, easily extractable glomalin, mycelium, arbuscular mycorrhizal fungi.

  18. Laboratory assessment of the influence of the proportion of waste foundry sand on the geotechnical engineering properties of clayey soils

    CSIR Research Space (South Africa)

    Mgangira, Martin B

    2006-01-01

    Full Text Available Soil improvement can be achieved through mechanical stabilisation using industrial byproducts. Clayey soils were blended with waste foundry sand to examine its influence on the geotechnical engineering properties of the soils. The waste foundry sand...

  19. Influence of salinity on bioremediation of oil in soil

    International Nuclear Information System (INIS)

    Rhykerd, R.L.; Weaver, R.W.; McInnes, K.J.

    1995-01-01

    Spills from oil production and processing result in soils being contaminated with oil and salt. The effect of NaCl on degradation of oil in a sandy-clay loam and a clay loam soil was determined. Soils were treated with 50 g kg -1 non-detergent motor oil (30 SAE). Salt treatments included NaCl amendments to adjust the soil solution electrical conductivities to 40, 120, and 200 dS m -1 . Soils were amended with nutrients and incubated at 25 o C. Oil degradation was estimated from the quantities of CO 2 evolved and from gravimetric determinations of remaining oil. Salt concentrations of 200 dS m -1 in oil amended soils resulted in a decrease in oil mineralized by 44% for a clay loam and 20% for a sandy-clay loam soil. A salt concentration of 40 dS m -1 reduced oil mineralization by about 10% in both soils. Oil mineralized in the oil amended clay-loam soil was 2-3 times greater than for comparable treatments of the sandy-clay loam soil. Amending the sandy-clay loam soil with 5% by weight of the clay-loam soil enhanced oil mineralization by 40%. Removal of salts from oil and salt contaminated soils before undertaking bioremediation may reduce the time required for bioremediation. (author)

  20. Factors influencing induction of adaptive response

    International Nuclear Information System (INIS)

    Misonoh, Jun; Ojima, Mitsuaki; Yonezawa, Morio

    2000-01-01

    Exposure to low doses of X-rays makes ICR mice resistant to subsequent sublethal irradiation and decrease mortality from hematopoietic death. Many factors, however, influence the induction of radioresistance. For instances, in ICR mice, the priming irradiation with 0.50 Gy was effective in the induction of radioresistance, when it is given at 6-week old, 2 weeks prior to subsequent sublethal irradiation. One hundred-fifty kV X-ray filtered off the soft component through 1.0 mm aluminum and 0.2 mm copper induces radioadaptive response as well as the harder radiation such as 260 kV X-ray filtered through 0.5 mm aluminum and 0.3 mm copper. Dose rate of priming irradiation also seemed to influence the induction of radioresistance. Priming irradiation with 0.50 Gy at 0.50 Gy/min and 0.25 Gy/min induced adaptive response, while same 0.50 Gy given at 0.063 Gy/min didn't. To make the matter complicated, when mice were pre-irradiated with 0.50 Gy at 0.013 Gy/min in the irradiation cell which was 1.2 x 1.2 x 1.4 times larger than the usual one, adaptive response was induced again. These results suggested that mice felt more uncomfortable when they were packing in the irradiation cell with little free space even for several minutes than when they were placed in the cell with much free space for about 40 minutes, and such a stress might give the mice some resistance to the subsequent sublethal irradiation. (author)

  1. influence of soil type differences on the distribution of dtpa

    African Journals Online (AJOL)

    Preferred Customer

    Fluvisol at Akaki in Ethiopia, classified according to the FAO-UNESCO Soil Classification System. The. Fluvisol is ... risk anticipated from the movement of metals through the soil ..... The Geology Department of the University of. Saskatchewan ...

  2. Influence of physical properties of soil on 137 Cs mobility

    International Nuclear Information System (INIS)

    Kanapickas, A.; Paulaitiene, I.; Mazeika, J.; Bauziene, I.

    2005-01-01

    A model to account for the mobility of radiocesium in soil is presented. The model requires a minimal set of coefficients that describe radiocesium migration and fixation rates, which can be related to physical soil properties. The peculiarities of experimental radiocesium profiles in soil are explained by the composition of soil, which affects the radiocesium fixation rate. It is shown that the migration of radiocesium in soil is governed by vertical convection of a mobile form, whereas diffusion is a slower process due to strong fixation. The results show that the velocity of vertical migration downward of mobile radiocesium can be set constant, because the overall migration rate depends on fixation. Modeling of experimental radiocesium soil profiles suggests that organic (humic) layers with reduced mineral content and humidity have a high radiocesium fixation rate. Soil structure that maintains high soil humidity and mineral content has an increased cesium exchangeability and. consequently, higher radiocesium mobility. (author)

  3. Test speed and other factors affecting the measurements of tree root properties used in soil reinforcement models

    NARCIS (Netherlands)

    Cofie, P.; Koolen, A.J.

    2001-01-01

    Measured values of the mechanical properties of tree roots are found to be affected by a number of factors. Shear properties of tree roots are found to be partly influenced by size of the testing equipment, level of soil compaction, deformation of the root material and estimated width of the shear

  4. Fate and bioavailability of 14C-pyrene and 14C-lindane in sterile natural and artificial soils and the influence of aging

    International Nuclear Information System (INIS)

    Šmídová, Klára; Hofman, Jakub; Ite, Aniefiok E.; Semple, Kirk T.

    2012-01-01

    Soil organic matter is used to extrapolate the toxicity and bioavailability of organic pollutants between different soils. However, it has been shown that other factors such as microbial activity are crucial. The aim of this study was to investigate if sterilization can reduce differences in the fate and bioavailability of organic pollutants between different soils. Three natural soils with increasing total organic carbon (TOC) content were collected and three artificial soils were prepared to obtain similar TOCs. Soils were sterilized and spiked with 14 C-pyrene and 14 C-lindane. Total 14 C radioactivity, HPCD extractability, and bioaccumulation in Eisenia fetida were measured over 56 days. When compared to non-sterile soils, differences between the natural and artificial soils and the influence of soil-contaminant contact time were generally reduced in the sterile soils (especially with middle TOC). The results indicate the possibility of using sterile soils as “the worst case scenario” in soil ecotoxicity studies. - Highlights: ► Sterile artificial and natural soils with the same TOC content were used. ► The fate and behavior of two 14 C-POPs were studied over 56 days after spiking. ► Sterilization reduced differences between artificial and natural soils. ► There was no effect of time (aging) in POPs bioaccumulation. ► Sterile soils may be used as “the worst case scenario” in POPs availability studies. - Sterilization reduced the differences in POPs fate and bioavailability between artificial and natural soils with the same TOC content and eliminated the influence of soil contact time.

  5. The Influence of Cattle Wastes on Degraded Savanna Soils of ...

    African Journals Online (AJOL)

    This paper examines the effects of cattle wastes on degraded savanna soils of Kwara State, Nigeria. A total of 40 soil samples were systematically collected from five quadrats of 12m x 12m. In 4 identified cattle sheds and 1 in adjacent fallow land (control field) on the same soil, climatic type and ecological zone. Standard ...

  6. Neighborhood size of training data influences soil map disaggregation

    Science.gov (United States)

    Soil class mapping relies on the ability of sample locations to represent portions of the landscape with similar soil types; however, most digital soil mapping (DSM) approaches intersect sample locations with one raster pixel per covariate layer regardless of pixel size. This approach does not take ...

  7. Influence of salinity and water content on soil microorganisms

    Directory of Open Access Journals (Sweden)

    Nan Yan

    2015-12-01

    Full Text Available Salinization is one of the most serious land degradation problems facing world. Salinity results in poor plant growth and low soil microbial activity due to osmotic stress and toxic ions. Soil microorganisms play a pivotal role in soils through mineralization of organic matter into plant available nutrients. Therefore it is important to maintain high microbial activity in soils. Salinity tolerant soil microbes counteract osmotic stress by synthesizing osmolytes which allows them to maintain their cell turgor and metabolism. Osmotic potential is a function of the salt concentration in the soil solution and therefore affected by both salinity (measured as electrical conductivity at a certain water content and soil water content. Soil salinity and water content vary in time and space. Understanding the effect of changes in salinity and water content on soil microorganisms is important for crop production, sustainable land use and rehabilitation of saline soils. In this review, the effects of soil salinity and water content on microbes are discussed to guide future research into management of saline soils.

  8. Local adaptation in migrated interior Douglas-fir seedlings is mediated by ectomycorrhizas and other soil factors.

    Science.gov (United States)

    Pickles, Brian J; Twieg, Brendan D; O'Neill, Gregory A; Mohn, William W; Simard, Suzanne W

    2015-08-01

    Separating edaphic impacts on tree distributions from those of climate and geography is notoriously difficult. Aboveground and belowground factors play important roles, and determining their relative contribution to tree success will greatly assist in refining predictive models and forestry strategies in a changing climate. In a common glasshouse, seedlings of interior Douglas-fir (Pseudotsuga menziesii var. glauca) from multiple populations were grown in multiple forest soils. Fungicide was applied to half of the seedlings to separate soil fungal and nonfungal impacts on seedling performance. Soils of varying geographic and climatic distance from seed origin were compared, using a transfer function approach. Seedling height and biomass were optimized following seed transfer into drier soils, whereas survival was optimized when elevation transfer was minimised. Fungicide application reduced ectomycorrhizal root colonization by c. 50%, with treated seedlings exhibiting greater survival but reduced biomass. Local adaptation of Douglas-fir populations to soils was mediated by soil fungi to some extent in 56% of soil origin by response variable combinations. Mediation by edaphic factors in general occurred in 81% of combinations. Soil biota, hitherto unaccounted for in climate models, interacts with biogeography to influence plant ranges in a changing climate. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  9. Fundamental factors influencing portal image quality

    International Nuclear Information System (INIS)

    Jaffray, D.A.

    1995-01-01

    It has been recognized that improved methods of verifying radiation field placement in external beam radiotherapy are required in order to make frequent checks of field placement feasible. As a result, a large number of electronic portal imaging systems have been developed as possible replacements for film. These developments have produced digital systems with faster acquisition and improved display contrast, however, the quality of the images acquired with such systems is still disappointing. This presentation examines many of the fundamental factors which limit the quality of radiographs obtained with a megavoltage radiotherapy beam. The size and shape of the radiation sources (focal and extra-focal) in radiotherapy machines and their influence on the spatial resolution of portal images are examined. Monte Carlo simulations of x-ray interactions within the patient determined that a significant fraction of the x-ray scatter generated in the patient is due to bremsstrahlung and positron annihilation. Depending on the detector, the scatter signal can reduce the differential signal-to-noise by 20%. Furthermore, a Monte Carlo study of the interaction of x-rays within typical fluoroscopic imaging detectors (metal plate/phosphor screen) demonstrates the degrading effect of energy absorption noise on the detective quantum efficiency of fluoroscopic based imaging systems. Finally, the spatial frequency content in the x-ray shadowgram is demonstrated to change with x-ray energy, resulting in images that appear to have reduced spatial resolution at megavoltage energies. The relative magnitude of each of these factors will be presented and recommendations for the next generation of portal imaging systems will be made

  10. Factors influencing creep model equation selection

    International Nuclear Information System (INIS)

    Holdsworth, S.R.; Askins, M.; Baker, A.; Gariboldi, E.; Holmstroem, S.; Klenk, A.; Ringel, M.; Merckling, G.; Sandstrom, R.; Schwienheer, M.; Spigarelli, S.

    2008-01-01

    During the course of the EU-funded Advanced-Creep Thematic Network, ECCC-WG1 reviewed the applicability and effectiveness of a range of model equations to represent the accumulation of creep strain in various engineering alloys. In addition to considering the experience of network members, the ability of several models to describe the deformation characteristics of large single and multi-cast collations of ε(t,T,σ) creep curves have been evaluated in an intensive assessment inter-comparison activity involving three steels, 21/4 CrMo (P22), 9CrMoVNb (Steel-91) and 18Cr13NiMo (Type-316). The choice of the most appropriate creep model equation for a given application depends not only on the high-temperature deformation characteristics of the material under consideration, but also on the characteristics of the dataset, the number of casts for which creep curves are available and on the strain regime for which an analytical representation is required. The paper focuses on the factors which can influence creep model selection and model-fitting approach for multi-source, multi-cast datasets

  11. Factors Affecting Soil Quality Maintenance In Northern Katsina State

    African Journals Online (AJOL)

    programs or scientifically based soil management strategies. Soil quality ... envelopment analysis techniques in the reconciliation of two ..... integrated plant production and environmental quality. In ..... Handbook of Soil Science. (Ed). Sumner ...

  12. Influence of moisture content on radon diffusion in soil

    International Nuclear Information System (INIS)

    Singh, M.; Ramola, R.C.; Singh, S.; Virk, H.S.

    1990-01-01

    Radon diffusion from soil has been studied as a function of the moisture content of the soil. A few simple experiments showed that up to a certain moisture content the radon diffusion increased with increasing moisture. A sharp rise in radon concentration occurred as the moisture was increased from the completely dry state to 13% water by weight. The radon flux was measured for columns of dry, moist and water saturated soil. The highest flux came from the column filled with moist soil. Water saturated soil gave the lowest flux because of the much lower diffusion coefficient of radon through water. (author)

  13. Influence of effective stress on swelling pressure of expansive soils

    Directory of Open Access Journals (Sweden)

    Baille Wiebke

    2016-01-01

    Full Text Available The volume change and shear strength behaviour of soils are controlled by the effective stress. Recent advances in unsaturated soil mechanics have shown that the effective stress as applicable to unsaturated soils is equal to the difference between the externally applied stress and the suction stress. The latter can be established based on the soil-water characteristic curve (SWCC of the soil. In the present study, the evolution of swelling pressure in compacted bentonite-sand mixtures was investigated. Comparisons were made between magnitudes of applied suction, suction stress, and swelling pressure.

  14. Chemical factors of soil polution in Taganrog as population health risk factors

    Directory of Open Access Journals (Sweden)

    G.T. Aydinov

    2017-03-01

    Full Text Available Our research goal was to perform a hygienic assessment of soil pollution with chemicals on areas aimed for housing and recreation zones in Taganrog, Rostov region. Due to the fact that surface layer of city soils is an open dynamic system which is tightly connected to atmosphere and hydrosphere we treated pollutants content in soils as indicators of territory anthropogenic transformation and technogenic load on population. We used atomic-adsorption spectrophotometry to detect heavy metals and highly efficient liquid chromatography to detect 3,4-benzpyrene content. The results comprise 660 examined soil samples taken from 19 monitoring points; they were examined to detect 7 pollutants content (lead, zinc, copper, nickel, cadmium, chromium, and mercury over 2008–2015; 144 samples were examined to detect 3,4-benzpyrene content over 2013–2015. We determined that priority pollutants among detected metals were zinc and lead; their content in city soils amounted up to 5.91 and 1.95 maximum permissible concentration. Complex indicator of city soils contamination varied from 1.61 to 2.02, long-term average annual value being 1.83. 3,4-benzpyrene was confirmed to be a substantial risk factor for population health as its concentrations exceeded maximum allowable values in 65.28 % of examined soil samples at average and maximum concentrations (2.45 and 38.05 MPC correspondingly. We recommend to include this chemical into systematic environmental quality monitoring. We detected regional peculiarities of soil pollution with chemicals on city territories aimed for housing, territories of pre-school children facilities, and recreation zones.

  15. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Curdy, R. [Laboratory for Environmental Biotechnology (LBE), Swiss Federal Institute of Technology Lausanne (EPFL) Station 6 CH, 1015 Lausanne (Switzerland); Zhao, F.J. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2010-10-15

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED{sub 50}) of Mo in different soils, explaining > 65% of the variance in ED{sub 50} for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  16. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    International Nuclear Information System (INIS)

    McGrath, S.P.; Mico, C.; Curdy, R.; Zhao, F.J.

    2010-01-01

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED 50 ) of Mo in different soils, explaining > 65% of the variance in ED 50 for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  17. The effect of Fe, Mn, Ni and Pb Load on Soil and its enrichment factor ratios in different soil grain size fractions as an Indicator for soil pollution

    International Nuclear Information System (INIS)

    Rabie, F.H.; Abdel-Sabour, M.F.

    2000-01-01

    An industrial area north of greater Cairo was selected to investigate the impact of intensive industrial activities on soil characteristics and Fe, Mn, Ni and Pb total content. The studied area was divided to six sectors according to its source of irrigation water and/or probability of pollution. Sixteen soil profiles were dug and soil samples were taken, air dried, fractionated to different grain size fractions, then total heavy metals (Fe, Mn, Ni and Pb) were determined using ICP technique. The enrichment factor for each metal for each soil fraction/soil layer was estimated and discussed. The highest EF ratios in the clay fraction was mainly with Pb which indicated the industrial impact on the soil. In case of sand fraction, Mn was the highest always compared to other studied metals. Concerning silt fraction, a varied accumulation of Fe, Mn, and Pb was observed with soil depth and different soil profiles

  18. Influence of black carbon addition on phenanthrene dissipation and microbial community structure in soil

    International Nuclear Information System (INIS)

    Wang Ping; Wang Haizhen; Wu Laosheng; Di Hongjie; He Yan; Xu Jianming

    2012-01-01

    Biodegradation processes and changes in microbial community structure were investigated in black carbon (BC) amended soils in a laboratory experiment using two soils (black soil and red soil). We applied different percentages of charcoal as BC (0%, 0.5% and 1% by weight) with 100 mg kg −1 of phenanthrene. Soil samples were collected at different incubation times (0, 7, 15, 30, 60, 120 d). The amendment with BC caused a marked decrease in the dissipation (ascribed to mainly degradation and/or sequestration) of phenanthrene residues from soil. Extracted phenanthrene in black soil with 1% BC were higher, oppositely in red soil, 0.5% BC amendments were higher. There were significant changes in the PLFA pattern in phenanthrene-spiked soils with time but BC had little effect on the microbial community structure of phenanthrene-spiked soils, as indicated by principal component analysis (PCA) of the PLFA signatures. - Highlights: ► Extracted phenanthrene increased substantially as the BC amount increased. ► Extracted phenanthrene in black soil with 1% BC were higher, oppositely in red soil. ► BC caused a marked decrease in the dissipation of phenanthrene from soil. ► PLFA pattern in phenanthrene-spiked soils with time had significant changes. - BC amendments on phenanthrene extraction were different for two soils and time was a more effective factor in microbial community changes.

  19. Assessing the influence of sustainable trail design and maintenance on soil loss

    Science.gov (United States)

    Marion, Jeff; Wimpey, Jeremy

    2017-01-01

    Natural-surfaced trail systems are an important infrastructure component providing a means for accessing remote protected natural area destinations. The condition and usability of trails is a critical concern of land managers charged with providing recreational access while preserving natural conditions, and to visitors seeking high quality recreational opportunities and experiences. While an adequate number of trail management publications provide prescriptive guidance for designing, constructing, and maintaining natural-surfaced trails, surprisingly little research has been directed at providing a scientific basis for this guidance. Results from a review of the literature and three scientific studies are presented to model and clarify the influence of factors that substantially influence trail soil loss and that can be manipulated by trail professionals to sustain high traffic while minimizing soil loss over time. Key factors include trail grade, slope alignment angle, tread drainage features, and the amount of rock in tread substrates. A new Trail Sustainability Rating is developed and offered as a tool for evaluating or improving the sustainability of existing or new trails.

  20. Assessing the influence of sustainable trail design and maintenance on soil loss.

    Science.gov (United States)

    Marion, Jeffrey L; Wimpey, Jeremy

    2017-03-15

    Natural-surfaced trail systems are an important infrastructure component providing a means for accessing remote protected natural area destinations. The condition and usability of trails is a critical concern of land managers charged with providing recreational access while preserving natural conditions, and to visitors seeking high quality recreational opportunities and experiences. While an adequate number of trail management publications provide prescriptive guidance for designing, constructing, and maintaining natural-surfaced trails, surprisingly little research has been directed at providing a scientific basis for this guidance. Results from a review of the literature and three scientific studies are presented to model and clarify the influence of factors that substantially influence trail soil loss and that can be manipulated by trail professionals to sustain high traffic while minimizing soil loss over time. Key factors include trail grade, slope alignment angle, tread drainage features, and the amount of rock in tread substrates. A new Trail Sustainability Rating is developed and offered as a tool for evaluating or improving the sustainability of existing or new trails. Published by Elsevier Ltd.

  1. The influence of organic-containing soil dust on ice nucleation and cloud properties

    Science.gov (United States)

    Hummel, Matthias; Grini, Alf; Berntsen, Terje K.; Ekman, Annica

    2017-04-01

    Natural mineral dust from desert regions is known to be the most important contributor to atmospheric ice-nucleating particles (INP) which induce heterogeneous ice nucleation in mixed-phase clouds. Its ability to nucleate ice effectively is shown by various laboratory (Hoose and Möhler 2012) and field results (DeMott et al. 2015) and its abundance in ice crystal residuals has also been shown (Cziczo et al. 2013). Thus it is an important player when representing mixed-phase clouds in climate models. MODIS satellite data indicate that 1 /4 of the global dust emission originates from semi-arid areas rather than from arid deserts (Ginoux et al. 2012). Here, organic components can mix with minerals within the soil and get into the atmosphere. These so-called 'soil dust' particles are ice-nucleating active at high sub-zero temperatures, i.e. at higher temperatures than pure desert dust (Steinke et al. 2016). In this study, soil dust is incorporated into the Norwegian Earth System Model (NorESM, Bentsen et al. 2013) and applied to a modified ice nucleation parameterization (Steinke et al. 2016). Its influence on the cloud ice phase is evaluated by comparing a control run, where only pure desert dust is considered, and a sensitivity experiment, where a fraction of the dust emissions are classified as soil dust. Both simulations are nudged to ERA-interim meteorology and they have the same loading of dust emissions. NorESM gives a lower annual soil dust emission flux compared to Ginoux et al. (2012), but the desert dust flux is similar to the MODIS-retrieved data. Although soil dust concentrations are much lower than desert dust, the NorESM simulations indicate that the annual INP concentrations from soil dust are on average lower by a just a factor of 4 than INP concentrations from pure desert dust. The highest soil dust INP concentrations occur at a lower height than for desert dust, i.e at warmer temperatures inside mixed-phase clouds. Furthermore, soil dust INP

  2. Characterization and influence of biochars on nitrous oxide emission from agricultural soil

    International Nuclear Information System (INIS)

    Wang, Zhenyu; Zheng, Hao; Luo, Ye; Deng, Xia; Herbert, Stephen; Xing, Baoshan

    2013-01-01

    Extensive use of biochar to mitigate N 2 O emission is limited by the lack of understanding on the exact mechanisms altering N 2 O emissions from biochar-amended soils. Biochars produced from giant reed were characterized and used to investigate their influence on N 2 O emission. Responses of N 2 O emission varied with pyrolysis temperature, and the reduction order of N 2 O emission by biochar (BC) was: BC200 ≈ BC600 > BC500 ≈ BC300 ≈ BC350 > BC400. The reduced emission was attributed to enhanced N immobilization and decreased denitrification in the biochar-amended soils. The remaining polycyclic aromatic hydrocarbons (PAHs) in low-temperature biochars (300–400 °C) played a major role in reducing N 2 O emission, but not for high-temperature biochars (500–600 °C). Removal of phenolic compounds from low-temperature (200–400 °C) biochars resulted in a surprising reduction of N 2 O emission, but the mechanism is still unknown. Overall, adding giant reed biochars could reduce N 2 O evolution from agricultural soil, thus possibly mitigating global warming. -- Highlights: ► C content of biochar increased with temperature but O and H content decreased. ► Biochars produced at 200–600 °C reduced N 2 O emissions from agricultural soil. ► PAHs in biochars (300–400 °C) seem a dominant factor for the reduced N 2 O emission. ► Phenolic compounds in biochars ( 2 O emission. -- Biochars (200–600 °C) produced from giant reed reduced N 2 O emissions from a soil due to enhanced N immobilization and decreased denitrification

  3. An Investigation into factors influencing the choice of business ...

    African Journals Online (AJOL)

    There was significant difference between male and female career influencing factors. There was no significant difference regarding the influence exercised by parent in the students' choice of Business Education. There is significant difference between male and female in the influence exerted by external factors in their ...

  4. The influence of bioturbation on the vertical distribution of soil organic matter in volcanic ash soils: a case study in northern Ecuador

    NARCIS (Netherlands)

    Tonneijck, F.H.; Jongmans, A.G.

    2008-01-01

    Soil faunal bioturbation ('bioturbation') is often cited as a major process influencing the vertical distribution of soil organic matter (SOM). The influence of bioturbation on vertical SOM transport is complex because it is the result of interaction between different groups of soil faunal species

  5. Influence of biochar on isoproturon partitioning and bioaccessibility in soil.

    Science.gov (United States)

    Reid, B J; Pickering, F L; Freddo, A; Whelan, M J; Coulon, F

    2013-10-01

    The influence of biochar (5%) on the loss, partitioning and bioaccessibility of (14)C-isoproturon ((14)C-IPU) was evaluated. Results indicated that biochar had a dramatic effect upon (14)C-IPU partitioning: (14)C-IPU extractability (0.01 M CaCl2) in biochar-amended treatments was reduced to <2% while, (14)C-IPU extractability in biochar free treatments decreased with ageing from 90% to 40%. A partitioning model was constructed to derive an effective partition coefficient for biochar:water (KBW of 7.82 × 10(4) L kg(-1)). This was two orders of magnitude greater than the apparent Kfoc value of the soil organic carbon:water (631 L kg(-1)). (14)C-radiorespirometry assays indicated high competence of microorganisms to mineralise (14)C-IPU in the absence of biochar (40.3 ± 0.9%). Where biochar was present (14)C-IPU mineralisation never exceeded 2%. These results indicate reduced herbicide bioaccessibility. Increasing IPU application to ×10 its recommended dose was ineffective at redressing IPU sequestration and its low bioaccessibility. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Effects of environmental factors and soil properties on topographic variations of soil respiration

    Directory of Open Access Journals (Sweden)

    K. Tamai

    2010-03-01

    Full Text Available Soil respiration rates were measured along different parts of a slope in (a an evergreen forest with common brown forest soil and (b a deciduous forest with immature soil. The effects of soil temperature, soil moisture and soil properties were estimated individually, and the magnitudes of these effects in the deciduous and evergreen forests were compared. In the evergreen forest with common brown forest soil, soil properties had the greatest effect on soil respiration rates, followed by soil moisture and soil temperature. These results may be explained by the fact that different soil properties matured within different environments. It can be argued that the low soil respiration rates in the low parts of the slope in the evergreen forest resulted from soil properties and not from wet soil conditions. In the deciduous forest, soil respiration rates were more strongly affected by soil moisture and soil temperature than by soil properties. These effects were likely due to the immaturity of the forest soil.

  7. 137Cs Transfer Factor from Latosol Soil to Swamp Gabbages (Ipomea Reptans Poir)

    International Nuclear Information System (INIS)

    Leli-Nirwani; Yurfida; Buchori

    2001-01-01

    A study of 137 Cs transfer factor from Latosol soil to swamp cabbages plant has been conducted using pot treatment system with complete random design. The aim of the research is to determine transfer factor of 137 Cs from latosol soil to swamp cabbages plant. Cs-137 concentration administered was 7.5287 kBq/pot. The number of swamp cabbages planted in 137 Cs treated soil and in cannot soil respectively was 12 pots filled with 1 kg soil/pot. After harvest, the weight of dried plant was measured. Transfer factor was determined according to the accumulation of 137 Cs concentration in swamp cabbages and soil and counted using Spectrometer Gamma. It was found that is a significant difference between 137 Cs concentration in swamp cabbages planted inthe treated soil and that of control soil. Transfer factor ranges between 0.02 and 0.13 with the averageof 0.08. (author)

  8. Growth and extracellular phosphatase activity of arbuscular mycorrhizal hyphae as influenced by soil organic matter

    DEFF Research Database (Denmark)

    Joner, E.J.; Jakobsen, I.

    1995-01-01

    Two experiments were set up to investigate the influence of soil organic matter on growth of arbuscular mycorrhizal (AM) hyphae and concurrent changes in soil inorganic P, organic P and phosphatase activity. A sandy loam soil was kept for 14 months under two regimes (outdoor where surplus...... additions. In soil with added clover alkaline phosphatase activity increased due to the presence of mycorrhizal hyphae. We suggest that mycorrhizas may influence the exudation of acid phosphatase by roots. Hyphae of G. invermaium did apparently not excrete extracellular phosphatases, but their presence may...

  9. Relationship between soil chemical factors and grassland diversity

    NARCIS (Netherlands)

    Janssens, F; Peeters, A; Tallowin, JRB; Bakker, JP; Bekker, RM; Fillat, F; Oomes, MJM

    Many studies carried out during these last few years have focused on the factors influencing plant diversity in species-rich grasslands. This is due to the fact that these ecosystems, among the most diversified in temperate climates, are extremely threatened; in some areas, they have almost

  10. Spatial distribution patterns of soil mite communities and their relationships with edaphic factors in a 30-year tillage cornfield in northeast China.

    Science.gov (United States)

    Liu, Jie; Gao, Meixiang; Liu, Jinwen; Guo, Yuxi; Liu, Dong; Zhu, Xinyu; Wu, Donghui

    2018-01-01

    Spatial distribution is an important topic in community ecology and a key to understanding the structure and dynamics of populations and communities. However, the available information related to the spatial patterns of soil mite communities in long-term tillage agroecosystems remains insufficient. In this study, we examined the spatial patterns of soil mite communities to explain the spatial relationships between soil mite communities and soil parameters. Soil fauna were sampled three times (August, September and October 2015) at 121 locations arranged regularly within a 400 m × 400 m monitoring plot. Additionally, we estimated the physical and chemical parameters of the same sampling locations. The distribution patterns of the soil mite community and the edaphic parameters were analyzed using a range of geostatistical tools. Moran's I coefficient showed that, during each sampling period, the total abundance of the soil mite communities and the abundance of the dominant mite populations were spatially autocorrelated. The soil mite communities demonstrated clear patchy distribution patterns within the study plot. These patterns were sampling period-specific. Cross-semivariograms showed both negative and positive cross-correlations between soil mite communities and environmental factors. Mantel tests showed a significant and positive relationship between soil mite community and soil organic matter and soil pH only in August. This study demonstrated that in the cornfield, the soil mite distribution exhibited strong or moderate spatial dependence, and the mites formed patches with sizes less than one hundred meters. In addition, in this long-term tillage agroecosystem, soil factors had less influence on the observed pattern of soil mite communities. Further experiments that take into account human activity and spatial factors should be performed to study the factors that drive the spatial distribution of soil microarthropods.

  11. Empirical Site Amplification Factors Incorporating Soil Nonlinearity in Taiwan

    Science.gov (United States)

    Kuo, C. H.; Chung, C. H.; Che-Min, L.; Huang, J. Y.; Wen, K. L.

    2017-12-01

    Characteristics of site amplifications caused by both crustal and subduction earthquakes are important in Taiwan. For example, seismic waves were amplified and led to significant building damages in the Taipei Basin by the 1986 Hualien offshore (subduction interface) and the 1999 Chi-Chi earthquakes (crustal), for which the epicentral distances were about 100 km. To understand local site amplifications in Taiwan, empirical site amplification factors for horizontal ground motions are studied using recently constructed strong motion and site databases for the free-field TSMIP stations in Taiwan. Records of large magnitude earthquakes of ML larger than six from 1994 to 2014 were selected for this study. Site amplification factors at site conditions with Vs30 of 120 m/s to 1500 m/s and base accelerations up to 0.7g were inferred from intensity ratios of station pairs within specific distances. The reference site condition is assumed as Vs30 of 760 m/s (B/C boundary). Preliminary results indicate: 1. Soil nonlinearity is more obviously at short periods (PGA, Sa0.3) than long periods (PGV, Sa1.0). 2. Soil nonlinearity is significant for stations belong to site classes of B, C, D, and E in Taiwan. 3. Effect of station-pair distance is seen at short periods (PGA and Sa0.3). 4. No significant different is found in site amplifications of crustal and subduction earthquakes. The result could be a reference for the Fa and Fv in Taiwan's building code.

  12. Influence of Climate Factors on Rice Yields in Cambodia

    Directory of Open Access Journals (Sweden)

    Dek Vimean Pheakdey

    2017-12-01

    Full Text Available Temperature and precipitation have been known as the key determinant factors to affect rice production in climate change. In this study, the relationship between climate variables and rice yields during 1993–2012 in Cambodia was analyzed and evaluated. The Ordinary Least Squares analysis was applied to examine the relationship of three climate variables (TCV including maximum temperature, minimum temperature and rainfall against seasonal rice yields. By this period, a remarkable increasing trend of annual temperature was observed whilst rainfall was not significantly changed. The TCV explains approximately 63% and 56% of the variability of rice yields in wet and dry seasons, respectively. It is found that in Cambodia, non-climate factors such as fertilizers, water, cultivars, and soil fertility cause 40% variation to rice yields, whereas the remaining 60% can be influenced by climate variability. The levels of temperature difference (LTD between maximum and minimum temperatures of the wet season (WS and dry season (DS were 7.0 and 8.6 oC, respectively. The lower value of LTD may cause the reduction of rice in WS (2.2 tons/ha as compared to that of DS (3.0 tons/ha. Rice yield has increased 50.5% and 33.8% in DS and WS, respectively, may due to the improvement of rice cultivation practices in Cambodia such as the better use of fertilizers, pest and weed control, and irrigation, and more effective rice cultivated protocol, as the increased trend of temperature may detrimentally affect rice yield. The breeding of heat and drought tolerance rice varieties and development of irrigation system are effective to reduce the negative influence from climate change to rice production in Cambodia.

  13. Influence of soil structure on contaminant leaching from injected slurry.

    Science.gov (United States)

    Amin, M G Mostofa; Pedersen, Christina Østerballe; Forslund, Anita; Veith, Tamie L; Laegdsmand, Mette

    2016-12-15

    Animal manure application to agricultural land provides beneficial organic matter and nutrients but can spread harmful contaminants to the environment. Contamination of fresh produce, surface water and shallow groundwater with the manure-borne pollutants can be a critical concern. Leaching and persistence of nitrogen, microorganisms (bacteriophage, E. coli, and Enterococcus) and a group of steroid hormone (estrogens) were investigated after injection of swine slurry into either intact (structured) or disturbed (homogeneous repacked) soil. The slurry was injected into hexaplicate soil columns at a rate of 50 t ha -1 and followed with four irrigation events: 3.5-h period at 10 mm h -1 after 1, 2, 3, and 4 weeks. The disturbed columns delayed the leaching of a conservative tracer and microorganisms in the first irrigation event compared to the intact columns due to the effect of disturbed macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils. In contrast, NO 3 -N leaching from the intact soil was higher for all events except the first event, probably due to a lower nitrification rate in the disturbed soil. A week after the last irrigation event, the redistribution of all slurry constituents except NO 3 -N in most of the sections of the soil column was higher for the disturbed soil. Total recovery of E. coli was significantly higher from the disturbed soil and total leaching of mineral nitrogen was significantly

  14. Factors affecting the determination of the isotopically exchangeable phosphorus in soils

    International Nuclear Information System (INIS)

    Morales, L.E.M.

    1981-06-01

    In order to evaluate the factors that affect the determination of the isotopically exchangeable phosphorus in soils (L value), various greenhouse experiments were carried out. The following factors were considered: carrier level; plant species; harvest time; nitrogen doses; nitrogen sources; culture conditions and soil type. A radioactive solution with an activity level of approximately 10 μCi 32 p/3 kg soil with different carrier levels was located in layers or mixed completely with the soil depending upon the experiment. (author)

  15. Soil type influence on Ag Nanoparticles by earthworms, Eisenia fetida

    DEFF Research Database (Denmark)

    Mariyadas, Jennifer; Mónica, Amorim; Scott-Fordsmand, Janeck James

    2014-01-01

    Earthworms are key sentinel organisms playing an important role in improving the soil structure. Here we tested the importance of soil type on the toxicity to silver nanoparticles (Ag NPs) to earthworms, Eisenia fetida. Silver nanoparticles are widely used in a range of consumer products mainly...... as antibacterial agents and thus causes potential risk to the environment once these particles are released into the environment [1]. In our tests, we were able to show that the earthworm toxicity was strongly dependent on the soil type, with strongest effect in low organic matter soil. Studies on the organic...... matter content, clay and cation exchange capacity along with the metal solution activity will provide insight into the bioavailability of metals in different soils, hence For each of the soil type the fate of the AgNPs was also measured....

  16. Urban water consumption and its influencing factors in China

    NARCIS (Netherlands)

    Fan, Liangxin; Gai, Lingtong; Tong, Yan; Li, Ruihua

    2017-01-01

    Factors that affect water consumption should be identified to develop effective public policies. However, factors influencing domestic water consumption in cities in China, particularly on a national scale, are unclear. In this study, urban water consumption and its influencing factors in 286

  17. Factors influencing choice of paediatrics as a career among medical ...

    African Journals Online (AJOL)

    None of the male students but 12 of the female students (30%) considered gender distribution to be a factor influencing their career choice (p=0.046). Conclusion. This study indicates that paediatrics is popular among female students and that several factors influence choice of this specialty. Understanding these factors may ...

  18. Report on a workshop on the measurement of soils to plant transfer factors for radionuclides

    International Nuclear Information System (INIS)

    1982-01-01

    This report includes the proceedings of the workshop on soil-plant transfer factors of radionuclides. Part 1 deals with a general introduction of soil-plant transfer factors, recommendations for the determination of these transfer factors and computer listing of transfer factors specified according to nuclide; type of crop; type of soil; and type of experiment. The second part offers the 12 contributions presented, of which several are included in INIS separately. (G.J.P.)

  19. Factors Influencing Arthropod Diversity on Green Roofs

    Directory of Open Access Journals (Sweden)

    Bracha Y. Schindler

    2011-01-01

    Full Text Available Green roofs have potential for providing substantial habitat to plants, birds, and arthropod species that are not well supported by other urban habitats. Whereas the plants on a typical green roof are chosen and planted by people, the arthropods that colonize it can serve as an indicator of the ability of this novel habitat to support a diverse community of organisms. The goal of this observational study was to determine which physical characteristics of a roof or characteristics of its vegetation correlate with arthropod diversity on the roof. We intensively sampled the number of insect families on one roof with pitfall traps and also measured the soil arthropod species richness on six green roofs in the Boston, MA area. We found that the number of arthropod species in soil, and arthropod families in pitfall traps, was positively correlated with living vegetation cover. The number of arthropod species was not significantly correlated with plant diversity, green roof size, distance from the ground, or distance to the nearest vegetated habitat from the roof. Our results suggest that vegetation cover may be more important than vegetation diversity for roof arthropod diversity, at least for the first few years after establishment. Additionally, we found that even green roofs that are small and isolated can support a community of arthropods that include important functional groups of the soil food web.

  20. Factors Influencing Prevention and Control of Malaria among ...

    African Journals Online (AJOL)

    AJRH Managing Editor

    investigate factors that influence malaria prevention and control practices among pregnant ... treatment of clinical cases and the promotion of ... influence their decision regarding malaria ..... have the ability to purchase anti-malaria drugs that.

  1. Factors influencing the adoption of mobile financial services in the ...

    African Journals Online (AJOL)

    Factors influencing the adoption of mobile financial services in the unbanked population. ... Inkanyiso: Journal of Humanities and Social Sciences ... the influences of the adoption behaviour at different level of market maturity and points of time.

  2. Factors influencing the usage of different types of malaria prevention ...

    African Journals Online (AJOL)

    Objective: To examine factors which influence the use of different types of malaria prevention ... risk areas, religion, education and income influenced ITN usage, whereas only age, malaria .... the uptake of IPTp given that the person would not.

  3. Factors influencing cassava - pulp fermentation period for gari ...

    African Journals Online (AJOL)

    Factors influencing cassava - pulp fermentation period for gari processing among ... Result of probit model analysis at 5% significance level shows an R value ... Marital status (2.236**) and respondents' cultural influences (1.960**) were ...

  4. The influence of e-waste recycling on the molecular ecological network of soil microbial communities in Pakistan and China.

    Science.gov (United States)

    Jiang, Longfei; Cheng, Zhineng; Zhang, Dayi; Song, Mengke; Wang, Yujie; Luo, Chunling; Yin, Hua; Li, Jun; Zhang, Gan

    2017-12-01

    Primitive electronic waste (e-waste) recycling releases large amounts of organic pollutants and heavy metals into the environment. As crucial moderators of geochemical cycling processes and pollutant remediation, soil microbes may be affected by these contaminants. We collected soil samples heavily contaminated by e-waste recycling in China and Pakistan, and analyzed the indigenous microbial communities. The results of this work revealed that the microbial community composition and diversity, at both whole and core community levels, were affected significantly by polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and heavy metals (e.g., Cu, Zn, and Pb). The geographical distance showed limited impacts on microbial communities compared with geochemical factors. The constructed ecological network of soil microbial communities illustrated microbial co-occurrence, competition and antagonism across soils, revealing the response of microbes to soil properties and pollutants. Two of the three main modules constructed with core operational taxonomic units (OTUs) were sensitive to nutrition (total organic carbon and total nitrogen) and pollutants. Five key OTUs assigned to Acidobacteria, Proteobacteria, and Nitrospirae in ecological network were identified. This is the first study to report the effects of e-waste pollutants on soil microbial network, providing a deeper understanding of the ecological influence of crude e-waste recycling activities on soil ecological functions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Factors that influencing veterinary drug’s metabolisation

    Directory of Open Access Journals (Sweden)

    Cristina, Romeo T.

    2007-12-01

    Full Text Available The paper wants to make a recall for the vet practitioners, of the main veterinary drug's metabolism rate influencing factors. Among the most important physiological factors (pharmacokinetics, sanguine flow and urinary ones, plasmatic proteins binding, enzymatic induction and inhibition are essential. Between the animal’s bounded factors more important are: species, individuality, age, sex, pregnancy, alimentation, genetic factors, and health status and from exogenous factors, daily rhythm, influences of chemical compounds and of the stress are presented.

  6. A Comparison of Factors that Influence the Lyophilization Process

    OpenAIRE

    Mnerie, Dumitru; Anghel, Gabriela Victoria; Mnerie, Alin Vasile; Cheveresan, Constantin

    2007-01-01

    The lyophilization (or freeze drying) process for agro-foods products depends on a series of technological factors that are in an inter-dependence with the process performance. This paper presents an expert method and its application. This method characterizes the influence factors of the lyophilization process, after the importance level of some factors in correlation with other factors, is defined. Only the most important factors were considered; influence considerations were made in relati...

  7. Factors for Microbial Carbon Sources in Organic and Mineral Soils from Eastern United States Deciduous Forests

    Energy Technology Data Exchange (ETDEWEB)

    Stitt, Caroline R. [Mills College, Oakland, CA (United States)

    2013-09-16

    Forest soils represent a large portion of global terrestrial carbon; however, which soil carbon sources are used by soil microbes and respired as carbon dioxide (CO2) is not well known. This study will focus on characterizing microbial carbon sources from organic and mineral soils from four eastern United States deciduous forests using a unique radiocarbon (14C) tracer. Results from the dark incubation of organic and mineral soils are heavily influenced by site characteristics when incubated at optimal microbial activity temperature. Sites with considerable differences in temperature, texture, and location differ in carbon source attribution, indicating that site characteristics play a role in soil respiration.

  8. Dirt in cane removal influenced by soil characteristics

    International Nuclear Information System (INIS)

    Fernandes, E.A.N.

    1997-01-01

    Dirt level in sugar cane consignments delivered to the factory is dependent on soil type, in association with harvesting system and weather conditions. Efforts for reducing soil in harvested cane have been made by sugar cane millers, especially improving the washing system installed before crushing. Instrumental neutron activation analysis has shown its potential for assessing dirt reductions in the washed material. Knowledge of elemental concentrations in the different soil fractions highlights the reliability of such measurements especially when taking into account the soil characteristics. (author)

  9. Holocene soil-geomorphic surfaces influence the role of salmon-derived nutrients in the coastal temperate rainforest of Southeast Alaska

    Science.gov (United States)

    David V. D' Amore; Nicholas S. Bonzey; Jacob Berkowitz; Janine Rüegg; Scott. Bridgham

    2011-01-01

    The influence of salmon-derived nutrients (SDN) is widely accepted as a potential factor in the maintenance of aquatic and terrestrial productivity in North American Coastal rainforests. Holocene alluvial landforms are intimately connected with the return of anadromous salmon, but the influence of the soils that occupy these landforms and support this important...

  10. Cs-137 soil to plant transfer factors derived from pot experiments and field studies

    International Nuclear Information System (INIS)

    Horak, O.; Gerzabek, M.H.; Mueck, K.

    1989-11-01

    Soil to plant transfer factors (TF) of 137 Cs for different crop plants were determined in pot experiments, in outdoor experiments with plastic containers of 50 l volume, and in field studies. In all cases the soil contamination with 137 Cs resulted from fallout after the Chernobyl reactor accident. Mean TF derived for outdoor plants on a fresh weight basis, ranged from 0,0017 (leaf vegetables) to 0,059 (rye straw) and showed characteristic differences depending on plant part and species. Generally, for fruits and potato tubers a lower TF was found than for vegetative plant parts. Moreover, the data were compared with those from former experiments, carried out before the Chernobyl accident. There is a good agreement for cereals (with exception of rye) fruit vegetables and fodder crops, while actual TF are substantially lower for potatoes, leaf and root vegetables, but higher for rye. A significant negative correlation was observed between the TF and the soil activity concentrations for 137 Cs. In container experiments the TF were found to be influenced mainly by the clay content of the soil. 11 refs., 2 figs., 2 tabs. (Authors)

  11. Analytical investigation of the influence of soil on tanks for seismic analysis of nuclear power plant

    International Nuclear Information System (INIS)

    Nakahara, M.; Wright, J.T.; Stevenson, J.D.

    1983-01-01

    When seismically designing equipment, such as ground supported tanks of nuclear power plants, the free field response spectra are normally applied to a model having a fixed base. The consideration of soil structure interaction, which routinely has been applied to nuclear power plant building structures constructed on the soil surface, has not normally been applied to equipment. In this study, the effect of soil structure interaction on seismic response of tanks will be evaluated as a function of soil surface stiffness and depth using the calculated soil stiffness equations developed by H. Tajimi. The authors investigated the influence of the soil properties and composition represented as soil springs which depend on the soil conditions (shear modulus, density, Poisson's ratio) and the depth of soil surface. The results of this study are presented in the form of graphs which may be used to identify the range of soil parameters which have a significant effect on the seismic response of typical nuclear power plant tanks. A typical example to express the influence of the soil surface for seismic response and vibrational characteristics is presented. (orig./HP)

  12. Sound absorption coefficient in situ: an alternative for estimating soil loss factors.

    Science.gov (United States)

    Freire, Rosane; Meletti de Abreu, Marco Henrique; Okada, Rafael Yuri; Soares, Paulo Fernando; GranhenTavares, Célia Regina

    2015-01-01

    The relationship between the sound absorption coefficient and factors of the Universal Soil Loss Equation (USLE) was determined in a section of the Maringá Stream basin, Paraná State, by using erosion plots. In the field, four erosion plots were built on a reduced scale, with dimensions of 2.0×12.5m. With respect to plot coverage, one was kept with bare soil and the others contained forage grass (Brachiaria), corn and wheat crops, respectively. Planting was performed without any type of conservation practice in an area with a 9% slope. A sedimentation tank was placed at the end of each plot to collect the material transported. For the acoustic system, pink noise was used in the measurement of the proposed monitoring, for collecting information on incident and reflected sound pressure levels. In general, obtained values of soil loss confirmed that 94.3% of material exported to the basin water came from the bare soil plot, 2.8% from the corn plot, 1.8% from the wheat plot, and 1.1% from the forage grass plot. With respect to the acoustic monitoring, results indicated that at 16kHz erosion plot coverage type had a significant influence on the sound absorption coefficient. High correlation coefficients were found in estimations of the A and C factors of the USLE, confirming that the acoustic technique is feasible for the determination of soil loss directly in the field. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Forest management type influences diversity and community composition of soil fungi across temperate forest ecosystems

    Directory of Open Access Journals (Sweden)

    Kezia eGoldmann

    2015-11-01

    Full Text Available Fungal communities have been shown to be highly sensitive towards shifts in plant diversity and species composition in forest ecosystems. However, little is known about the impact of forest management on fungal diversity and community composition of geographically separated sites. This study examined the effects of four different forest management types on soil fungal communities. These forest management types include age class forests of young managed beech (Fagus sylvatica L., with beech stands age of approximately 30 years, age class beech stands with an age of approximately 70 years, unmanaged beech stands, and coniferous stands dominated by either pine (Pinus sylvestris L. or spruce (Picea abies Karst. which are located in three study sites across Germany. Soil were sampled from 48 study plots and we employed fungal ITS rDNA pyrotag sequencing to assess the soil fungal diversity and community structure.We found that forest management type significantly affects the Shannon diversity of soil fungi and a significant interaction effect of study site and forest management on the fungal OTU richness. Consequently distinct fungal communities were detected in the three study sites and within the four forest management types, which were mainly related to the main tree species. Further analysis of the contribution of soil properties revealed that C/N ratio being the most important factor in all the three study sites whereas soil pH was significantly related to the fungal community in two study sites. Functional assignment of the fungal communities indicated that 38% of the observed communities were Ectomycorrhizal fungi (ECM and their distribution is significantly influenced by the forest management. Soil pH and C/N ratio were found to be the main drivers of the ECM fungal community composition. Additional fungal community similarity analysis revealed the presence of study site and management type specific ECM genera.This study extends our knowledge

  14. Forest Management Type Influences Diversity and Community Composition of Soil Fungi across Temperate Forest Ecosystems.

    Science.gov (United States)

    Goldmann, Kezia; Schöning, Ingo; Buscot, François; Wubet, Tesfaye

    2015-01-01

    Fungal communities have been shown to be highly sensitive toward shifts in plant diversity and species composition in forest ecosystems. However, little is known about the impact of forest management on fungal diversity and community composition of geographically separated sites. This study examined the effects of four different forest management types on soil fungal communities. These forest management types include age class forests of young managed beech (Fagus sylvatica L.), with beech stands age of approximately 30 years, age class beech stands with an age of approximately 70 years, unmanaged beech stands, and coniferous stands dominated by either pine (Pinus sylvestris L.) or spruce (Picea abies Karst.) which are located in three study sites across Germany. Soil were sampled from 48 study plots and we employed fungal ITS rDNA pyrotag sequencing to assess the soil fungal diversity and community structure. We found that forest management type significantly affects the Shannon diversity of soil fungi and a significant interaction effect of study site and forest management on the fungal operational taxonomic units richness. Consequently distinct fungal communities were detected in the three study sites and within the four forest management types, which were mainly related to the main tree species. Further analysis of the contribution of soil properties revealed that C/N ratio being the most important factor in all the three study sites whereas soil pH was significantly related to the fungal community in two study sites. Functional assignment of the fungal communities indicated that 38% of the observed communities were Ectomycorrhizal fungi (ECM) and their distribution is significantly influenced by the forest management. Soil pH and C/N ratio were found to be the main drivers of the ECM fungal community composition. Additional fungal community similarity analysis revealed the presence of study site and management type specific ECM genera. This study extends our

  15. [Advance in researches on vegetation cover and management factor in the soil erosion prediction model].

    Science.gov (United States)

    Zhang, Yan; Yuan, Jianping; Liu, Baoyuan

    2002-08-01

    Vegetation cover and land management are the main limiting factors of soil erosion, and quantitative evaluation on the effect of different vegetation on soil erosion is essential to land use and soil conservation planning. The vegetation cover and management factor (C) in the universal soil loss equation (USLE) is an index to evaluate this effect, which has been studied deeply and used widely. However, the C factor study is insufficient in China. In order to strengthen the research of C factor, this paper reviewed the developing progress of C factor, and compared the methods of estimating C value in different USLE versions. The relative studies in China were also summarized from the aspects of vegetation canopy coverage, soil surface cover, and root density. Three problems in C factor study were pointed out. The authors suggested that cropland C factor research should be furthered, and its methodology should be unified in China to represent reliable C values for soil loss prediction and conservation planning.

  16. Relative importance of natural and anthropogenic factors influencing karst rocky desertification

    Science.gov (United States)

    Xu, Erqi; Zhang, Hongqi

    2017-04-01

    As the most severe ecological issue in southwest China, karst rocky desertification (KRD) has both threatened and constrained regional sustainable development. Comprehensively understanding the relationship between the evolution of KRD and relevant driving data would provide more information to combat KRD in such complex karst environments. Past studies have been limited in quantifying the relative importance of driving factors influencing fine-scale KRD evolution, and have also lacked insight into their interactive impacts. To address these issues, we have used geographical information system techniques and a geographical detector model to explore the spatial consistency of driving factors and their interactions in relation to the evolution of KRD. Changshun County in China was selected as a representative area for the study. Nine relevant driving factors, including both natural and anthropogenic factors, were studied in regard to their relationships with KRD transformation between 2000 and 2010. Our results demonstrate the relative importance of driving data in influencing the improvement and deterioration of KRD. Lithology, soil type and road influence are identified as the leading factors. Interestingly, to our study at least, there is no significant difference between the impacts of natural and anthropogenic factors influencing KRD improvement, and even natural factors have a higher impact on KRD deterioration. Factors were found to enhance the influence of each other for KRD transformation. In particular, the results show a non-linearly enhanced effect between driving factors, which significantly aggravates KRD. New information found in our study helps to effectively control and restore areas afflicted by KRD.

  17. Influence of hydraulic hysteresis on the mechanical behavior of unsaturated soils and interfaces

    Science.gov (United States)

    Khoury, Charbel N.

    Unsaturated soils are commonly widespread around the world, especially at shallow depths from the surface. The mechanical behavior of this near surface soil is influenced by the seasonal variations such as rainfall or drought, which in turn may have a detrimental effect on many structures (e.g. retaining walls, shallow foundations, mechanically stabilized earth walls, soil slopes, and pavements) in contact with it. Thus, in order to better understand this behavior, it is crucial to study the complex relationship between soil moisture content and matric suction (a stress state variable defined as pore air pressure minus pore water pressure) known as the Soil Water Characteristic Curve (SWCC). In addition, the influence of hydraulic hysteresis on the behavior of unsaturated soils, soil-structure interaction (i.e. rough and smooth steel interfaces, soil-geotextile interfaces) and pavement subgrade (depicted herein mainly by resilient modulus, Mr) was also studied. To this end, suction-controlled direct shear tests were performed on soils, rough and smooth steel interfaces and geotextile interface under drying (D) and wetting after drying (DW). The shearing behavior is examined in terms of the two stress state variables, matric suction and net normal stress. Results along the D and DW paths indicated that peak shear strength increased with suction and net normal stress; while in general, the post peak shear strength was not influenced by suction for rough interfaces and no consistent trend was observed for soils and soil-geotextiles interfaces. Contrary to saturated soils, results during shearing at higher suction values (i.e. 25 kPa and above) showed a decrease in water content eventhough the sample exhibited dilation. A behavior postulated to be related to disruption of menisci and/or non-uniformity of pore size which results in an increase in localized pore water pressures. Interestingly, wetting after drying (DW) test results showed higher peak and post peak shear

  18. Oxygen diffusion in soils: Understanding the factors and processes needed for modeling

    Directory of Open Access Journals (Sweden)

    José Neira

    2015-08-01

    Full Text Available Oxygen is an important element for plant growth. Reducing its concentration in the soil affects plant physiological processes such as nutrient and water uptake as well as respiration, the redox potential of soil elements and the activity of microorganisms. The main mechanism of oxygen transport in the soil is by diffusion, a dynamic process greatly influenced by soil physical properties such as texture and structure, conditioning, pore size distribution, tortuosity and connectivity. Organic matter is a modifying agent of the soil's chemical and physical properties, affecting its structure and the porous matrix, which are determinants of oxygen transport. This study reviews the theory of soil gas diffusion and the effect of soil organic matter on the soil's physical properties and transport of gases. It also reviews gas diffusion models, particularly those including the effect of soil organic matter.

  19. Factors influencing electric utility expansion. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Masud, E. [ed.

    1977-01-01

    This report, Vol. 2, submitted by the General Electric Co., identifies factors that should be considered in planning interconnected systems and discusses how these factors relate to one another. The objective is to identify all the factors and classify them by their use and importance in arriving at a decision. Chapter 2 discusses the utility system and its system behavior characteristics, emphasizing behavior that affects the planning of the bulk-power generation and transmission system. Chapter 3 introduces interconnection planning by discussing the new system characteristics brought to operation and planning. Forty-two factors associated with cost, reliability, constraints, and coordination are related to each other by factor trees. Factor trees display the relationship of one factor such as reliability to more-detailed factors which in turn are further related to individual characteristics of facilities. These factor trees provide a structure to the presentation. A questionnaire including the 42 factors was completed by 52 system planners from utility companies and government authorities. The results of these questionnaires are tabulated and presented with pertinent discussion of each factor. Chapter 4 deals with generation planning, recognizing the existence of interconnections. Chapter 5 addresses transmission planning, questions related to reliability and cost measures and constraints, and factors related to both analytical techniques and planning procedures. The chapter ends with a discussion of combined generation-transmission planning. (MCW)

  20. Native temperature regime influences soil response to simulated warming

    Science.gov (United States)

    Timothy G. Whitby; Michael D. Madritch

    2013-01-01

    Anthropogenic climate change is expected to increase global temperatures and potentially increase soil carbon (C) mineralization, which could lead to a positive feedback between global warming and soil respiration. However the magnitude and spatial variability of belowground responses to warming are not yet fully understood. Some of the variability may depend...

  1. Fate and bioavailability of ¹⁴C-pyrene and ¹⁴C-lindane in sterile natural and artificial soils and the influence of aging.

    Science.gov (United States)

    Smídová, Klára; Hofman, Jakub; Ite, Aniefiok E; Semple, Kirk T

    2012-12-01

    Soil organic matter is used to extrapolate the toxicity and bioavailability of organic pollutants between different soils. However, it has been shown that other factors such as microbial activity are crucial. The aim of this study was to investigate if sterilization can reduce differences in the fate and bioavailability of organic pollutants between different soils. Three natural soils with increasing total organic carbon (TOC) content were collected and three artificial soils were prepared to obtain similar TOCs. Soils were sterilized and spiked with (14)C-pyrene and (14)C-lindane. Total (14)C radioactivity, HPCD extractability, and bioaccumulation in Eisenia fetida were measured over 56 days. When compared to non-sterile soils, differences between the natural and artificial soils and the influence of soil-contaminant contact time were generally reduced in the sterile soils (especially with middle TOC). The results indicate the possibility of using sterile soils as "the worst case scenario" in soil ecotoxicity studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Influence of long-term fertilization on soil enzyme activities

    Directory of Open Access Journals (Sweden)

    Alina Dora SAMUEL

    2009-05-01

    Full Text Available Soil enzyme activities (actual and potential dehydrogenase, catalase, acid and alkaline phosphatase were determined in the 0–10, 10–20, and 20–30 cm layers of a brown luvic soil submitted to a complex fertilization experiment with different types of green manure. It was found that each activity decreased with increasing sampling depth. It should be emphasized that greenmanuring of maize led to a significant increase in each of the five enzymatic activities determined. The enzymatic indicators of soil quality calculated from the values of enzymatic activities showed the order: lupinus + rape + oat > lupinus > vetch + oat + ryegrass > lupinus + oat + vetch > unfertilized plot. This order means that by determination of enzymatic activities valuable information can be obtained regarding fertility status of soils. There were significant correlations of soil enzyme activities with chemical properties.

  3. Influence of biochar on isoproturon partitioning and bioaccessibility in soil

    International Nuclear Information System (INIS)

    Reid, B.J.; Pickering, F.L.; Freddo, A.; Whelan, M.J.; Coulon, F.

    2013-01-01

    The influence of biochar (5%) on the loss, partitioning and bioaccessibility of 14 C-isoproturon ( 14 C-IPU) was evaluated. Results indicated that biochar had a dramatic effect upon 14 C-IPU partitioning: 14 C-IPU extractability (0.01 M CaCl 2 ) in biochar-amended treatments was reduced to 14 C-IPU extractability in biochar free treatments decreased with ageing from 90% to 40%. A partitioning model was constructed to derive an effective partition coefficient for biochar:water (K BW of 7.82 × 10 4 L kg −1 ). This was two orders of magnitude greater than the apparent K foc value of the soil organic carbon:water (631 L kg −1 ). 14 C-radiorespirometry assays indicated high competence of microorganisms to mineralise 14 C-IPU in the absence of biochar (40.3 ± 0.9%). Where biochar was present 14 C-IPU mineralisation never exceeded 2%. These results indicate reduced herbicide bioaccessibility. Increasing IPU application to ×10 its recommended dose was ineffective at redressing IPU sequestration and its low bioaccessibility. Highlights: •Biochar had a dramatic effect on IPU partitioning. •IPU extractability was reduced to BW ) was 7.82 × 10 4 L kg −1 . •K BW was 124 times greater than the apparent K foc value of the control. •Biochar precluded microbial bioaccessibility – no catabolic response was observed. -- Biochar dramatically reduced 14 C-IPU extractability ( BW being ×123 greater than the apparent K foc . Correspondingly, microbial bioaccessibility of IPU was negligible

  4. Dermal factors influencing measurement of skin autofluorescence

    NARCIS (Netherlands)

    Noordzij, Margaretha J.; Lefrandt, Johan; Graaff, Reindert; Smit, Andries J.

    Background: Skin autofluorescence (SAF) is a noninvasive marker of accumulation of advanced glycation end products. It predicts cardiovascular complications and mortality in diabetes and renal failure. We assessed the influence of potential common confounders in SAF measurement, by determining the

  5. factors influencing condom use among nigerian undergraduates

    African Journals Online (AJOL)

    2012-12-01

    Dec 1, 2012 ... Nigeria. Study design: Both qualitative (focus group discussions) and quantitative (cross-sectional ... Keywords: Condom, unsafe sex, HIV, gender, undergraduates. ..... QUESTIONS: the following may influence condom.

  6. Factors mediating the restoration of structurally degraded soils

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Moldrup, Per; Schjønning, Per

    with the ability of soils to perform these functions. The present study examines the roles of clay mineralogy, native organic matter, and exogenous organic material on the restoration of structurally degraded soils. Totally seven soils from Denmark and Ghana - five soils dominated by illites, one kaolinitic soil...... the incubation period, structural stability estimated as the amount of water-dispersible clay decreased with prevailing moisture content, and native organic matter. Also, microbial activity significantly increased with addition of exogenous organic matter. At the end of incubation, there was significant...... macroaggregation, decreased bulk density, and increased equivalent pore diameter and tortuosity (derived from measurements of soil-gas diffusivity and soil-air permeability) for all soils. Although aggregate friability was not affected by clay type, aggregate workability was highest for the kaolinitic soil...

  7. Influence of conventional biochar and ageing biochar application to arable soil on soil fertility and plant yield

    Science.gov (United States)

    Dvořáčková, Helena; Záhora, Jaroslav; Elbl, Jakub; Kynický, Jindřich; Hladký, Jan; Brtnický, Martin

    2017-04-01

    Biochar represents very controversial material which is product of pyrolysis. According to many studies biochar has positive effect on physical and chemical properties such as pH, conductivity, aggregates stability etc. Unfortunately biochar is product of combustion, so it can content toxic substance as are aromatic compound. These substances may have a negative effect on yield and microbial activities in soil. Our aim was eliminated concentration of toxic compound but preserved positive effect of biochar on soil properties. We was ageing/ activating of biochar in water environment and for soil inoculum we used native soil from landscape. Moreover two types of biochar was tested by pot experiment with seven variants, where conventional biochar from residual biomass and ageing biochar were applied in different doses: 10 t/ha, 20t/ha and 50 t/ha. Pots were placed in green house for 90 days and after the end of experiment the following parameters of soil fertility, health and quality were evaluated: content of soil organic matter, arbuscular mycorrhizal colonisation of Lactuca sativa L. roots, leaching of mineral nitrogen, changes in plant available nutrient content, EC and pH. Above all the total yield of indicator plant was observed. The significant (P plant yield and soil properties were found. The application of conventional biochar didn't have positive effect on plant yield in comparison with ageing biochar. The positive effect of ageing biochar addition on soil fertility was directly proportional to the dose which were applied - increasing in dose of ageing biochar resulted in increase of plant yield. Moreover the special experimental containers were used, where we was able to monitor the development of root in soil with and without addition of biochar (conventional or ageing). The positive influence of ageing biochar addition into soil on development of Lactuca sativa L. roots was observed.

  8. Topsoil and subsoil properties influence phosphorus leaching from four agricultural soils.

    Science.gov (United States)

    Andersson, Helena; Bergström, Lars; Djodjic, Faruk; Ulén, Barbro; Kirchmann, Holger

    2013-01-01

    Eutrophication, a major problem in many fresh and brackish waters, is largely caused by nonpoint-source pollution by P from agricultural soils. This lysimeter study examined the influence of P content, physical properties, and sorption characteristics in topsoil and subsoil on P leaching measured during 21 mo in 1-m-long, undisturbed soil columns of two clay and two sandy soils. Total P losses during the period varied between 0.65 and 7.40 kg ha. Dissolved reactive P was the dominant form in leachate from the sandy soils and one clay soil, varying from 48 to 76%. Particulate P dominated in leachate from the other clay soil, where low pH (5.2) in the subsoil decreased aggregate stability and thereby probably increased the dispersion of clay particles. Phosphorus leaching was small from soils with high P sorption index (PSI) and low P saturation (35% of PSI) in the profile. High sorption capacity in the subsoil was more important for P leaching in sandy soils than in clay soils with macropore flow, where the effect of high sorption capacity was reduced due to less interaction between percolating water and the soil matrix. The results suggest that P leaching is greatly affected by subsoil properties and that topsoil studies, which dominate current research, are insufficient for assessing P leaching in many soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  9. Pyrolysis temperature influences ameliorating effects of biochars on acidic soil.

    Science.gov (United States)

    Wan, Qing; Yuan, Jin-Hua; Xu, Ren-Kou; Li, Xing-Hui

    2014-02-01

    The biochars were prepared from straws of canola, corn, soybean, and peanut at different temperatures of 300, 500, and 700 °C by means of oxygen-limited pyrolysis.Amelioration effects of these biochars on an acidic Ultisol were investigated with incubation experiments, and application rate of biochars was 10 g/kg. The incorporation of these biochars induced the increase in soil pH, soil exchangeable base cations, base saturation, and cation exchange capacity and the decrease in soil exchangeable acidity and exchangeable Al. The ameliorating effects of biochars on acidic soil increased with increase in their pyrolysis temperature. The contribution of oxygen-containing functional groups on the biochars to their ameliorating effects on the acidic soil decreased with the rise in pyrolysis temperature, while the contribution from carbonates in the biochars changed oppositely. The incorporation of the biochars led to the decrease in soil reactive Al extracted by 0.5mol/L CuCl2, and the content of reactive Al was decreased with the increase in pyrolysis temperature of incorporated biochars. The biochars generated at 300 °C increased soil organically complexed Al due to ample quantity of oxygen-containing functional groups such as carboxylic and phenolic groups on the biochars, while the biochars generated at 500 and 700 °C accelerated the transformation of soil exchangeable Al to hydroxyl-Al polymers due to hydrolysis of Al at higher pH. Therefore, the crop straw-derived biochars can be used as amendments for acidic soils and the biochars generated at relatively high temperature have great ameliorating effects on the soils.

  10. Influence of low temperatures on aggregate disruption of heavy clay soils

    Directory of Open Access Journals (Sweden)

    Jana Kozlovsky Dufková

    2010-01-01

    Full Text Available Heavy clay soils that are normally resistant to wind erosion, from study site Ostrožská Nová Ves si­tua­ted in the foothills of the Bílé Karpaty Mountains, Czech Republic, were a subject of laboratory analyses. The analyses should found out the influence of overwinter processes on disruption of soil aggregates and thus reason of vulnerability to soil loss by wind. Two overwinter processes were observed – freezing and thawing, and freeze-drying of the soil. Both processes have indicated the increasing of erodible fraction in dependence of water content of analysed soils. Exposed frozen clay soils that freeze-dries during the winter in the foothills of Bílé Karpaty, leaves soils highly erodible in late winter and early spring.

  11. Study of the trace metal ion influence on the turnover of soil organic matter in cultivated contaminated soils

    International Nuclear Information System (INIS)

    Dumat, C.; Quenea, K.; Bermond, A.; Toinen, S.; Benedetti, M.F.

    2006-01-01

    The role of metals in the behaviour of soil organic matter (SOM) is not well documented. Therefore, we investigated the influence of metals (Pb, Zn, Cu and Cd) on the dynamic of SOM in contaminated soils where maize (C 4 plant) replaced C 3 cultures. Three pseudogley brown leached soil profiles under maize with a decreasing gradient in metals concentrations were sampled. On size fractions, stable carbon isotopic ratio (δ 13 C), metals, organic carbon and nitrogen concentrations were measured in function of depth. The determined sequence for the amount of C 4 organic matter in the bulk fractions: M 3 (0.9) > M 2 (0.4) > M 1 (0.3) is in agreement with a significant influence of metals on the SOM turnover. New C 4 SOM, mainly present in the labile coarser fractions and less contaminated by metals than the stabilised C 3 SOM of the clay fraction, is more easily degraded by microorganisms. - Measure of δ 13 C and total metal concentrations in size fractions of contaminated soils suggests an influence of metals on the soil organic matter dynamic

  12. External factors influencing the environmental performance of South African firms

    CSIR Research Space (South Africa)

    Peart, R

    2001-01-01

    Full Text Available This article reviews the external factors that influence environmental performance of companies in South Africa, drawing on international and local literature. After considering factors within the natural, social, economic and institutional...

  13. Factors influencing women\\'s decisions to purchase specific children ...

    African Journals Online (AJOL)

    Factors influencing women\\'s decisions to purchase specific children\\'s ... they had selected a children's multi-nutrient supplement with the intention of buying it. ... Price, performance and brand loyalty, affect and normative factors were most ...

  14. Factors influencing the pattern of malnutrition among acutely ill ...

    African Journals Online (AJOL)

    Factors influencing the pattern of malnutrition among acutely ill children presenting in ... height/length) measurements and z-scores calculated for the individual nutritional ... The factors associated with malnutrition included early introduction of ...

  15. The influence of fire history, plant species and post-fire management on soil water repellency in a Mediterranean catchment

    NARCIS (Netherlands)

    Keesstra, Saskia; Wittenberg, Lea; Maroulis, Jerry; Sambalino, Francesco; Malkinson, Dan; Cerdà, Artemi; Pereira, Paulo

    2017-01-01

    Fire is a key factor impacting soil hydrology in many Mediterranean catchments. Soil water repellency (SWR) can stimulate land degradation processes by reducing the affinity of soil and water thereby triggering a reduction in soil fertility and increasing soil and water losses. The effects of two

  16. Influences of liming on the soil-plant transfer of Ra-226 from acid soils field experiments

    International Nuclear Information System (INIS)

    Eriksson, Aa.

    1985-01-01

    The effects of liming of the plough layer in the early sixties on the contents of exchangeable Ca and Ra-226 in soil, and on the contents of Ca and Ra in the crops in the early eighties have been investigated. It was found that liming, while increasing the amounts of Ca, reduced the amounts of Ra and the ratio Ra/Ca exchangeable in soil. Liming influenced the plant upake of Ra more for the vegetative than for the generative parts of the grain crops. However, the reduction of the Ra/Ca-ratio in the former was not as effective as in the soil. In the grain it was uncertain. The difference can, however, be explained by the fact that the minerals in straw and grain are more or less taken from different layers of the soil profile. The crop is more dependant on the plough layer during the early development than later, when grain is developed

  17. Investigation of Influence Zones Induced by Shallow Tunnelling in Soft Soils

    NARCIS (Netherlands)

    Vu Minh, N.; Broere, W.; Bosch, J.W.

    2017-01-01

    The extent of the influence zone affected by shallow tunnelling depends on the value of volume loss which normally represents the amount of over-excavation and stress changes induced in the soil. This paper combines upper and lower estimates of volume loss for different soft soils and

  18. Development of earthworm burrow systems and the influence of earthworms on soil hydrology

    NARCIS (Netherlands)

    Ligthart, T.N.

    1996-01-01


    Inoculation of earthworms can help to restore or ameliorate land qualities. Earthworms create burrows and alter the structure of the soil matrix, which influence the water infiltration, drainage, water retention and the aeration of the soil. The way and rate of the development of

  19. Variability in urban soils influences the health and growth of native tree seedlings

    Science.gov (United States)

    Clara C. Pregitzer; Nancy F. Sonti; Richard A. Hallett

    2016-01-01

    Reforesting degraded urban landscapes is important due to the many benefits urban forests provide. Urban soils are highly variable, yet little is known about how this variability in urban soils influences tree seedling performance and survival. We conducted a greenhouse study to assess health, growth, and survival of four native tree species growing in native glacial...

  20. Conceptual Modeling of the Influence of Wetting and Drying Cycles on Soil Aggregation and Stabilization

    Science.gov (United States)

    Albalasmeh, A. A.; Ghezzehei, T.

    2011-12-01

    Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength and indirectly influences most biological and chemical processes that occur in and around soil. The interaction of environmental and biotic agents influences the physical condition of the soil, particularly through soil structural evolution. Wetting and drying cycles are important environmental processes known to enhance aggregation, while clay minerals, sesquioxides and soil organic matter (SOM) are the soil solids most involved in soil structural development. We hypothesize that drying of capillary water transports suspended and/or dissolved cementing agents toward inter-particle contacts and eventually deposits part of the colloidal mass forming inter-particle bonds. Here, we will show the role of wetting and drying cycles on soil aggregation and stabilization and how these cycles transport and deposit organic cementing agents at the inter-particle contact. We will present results of the effect of particle size, number of wetting and drying cycles, viscosity, molecule length and concentration of suspended and/or dissolved cementing agents on soil aggregation and stabilization.

  1. Influence of soil structure on contaminant leaching from injected slurry

    DEFF Research Database (Denmark)

    Amin, M. G. Mostofa; Pedersen, Christina Østerballe; Forslund, Anita

    2016-01-01

    at a rate of 50 t ha(-1) and followed with four irrigation events: 3.5-h period at 10 mm h(-1) after 1, 2, 3, and 4 weeks. The disturbed columns delayed the leaching of a conservative tracer and microorganisms in the first irrigation event compared to the intact columns due to the effect of disturbed...... macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect...... of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils...

  2. Spatial variability and its main controlling factors of the permafrost soil-moisture on the northern-slope of Bayan Har Mountains in Qinghai-Tibet Plateau

    Science.gov (United States)

    Cao, W.; Sheng, Y.

    2017-12-01

    The soil moisture movement is an important carrier of material cycle and energy flow among the various geo-spheres in the cold regions. It is very critical to protect the alpine ecology and hydrologic cycle in Qinghai-Tibet Plateau. Especially, it becomes one of the key problems to reveal the spatial-temporal variability of soil moisture movement and its main influence factors in earth system science. Thus, this research takes the north slope of Bayan Har Mountains in Qinghai-Tibet Plateau as a case study. The present study firstly investigates the change of permafrost moisture in different slope positions and depths. Based on this investigation, this article attempts to investigate the spatial variability of permafrost moisture and identifies the key influence factors in different terrain conditions. The method of classification and regression tree (CART) is adopted to identify the main controlling factors influencing the soil moisture movement. And the relationships between soil moisture and environmental factors are revealed by the use of the method of canonical correspondence analysis (CCA). The results show that: 1) the change of the soil moisture on the permafrost slope is divided into 4 stages, including the freezing stability phase, the rapid thawing phase, the thawing stability phase and the fast freezing phase; 2) this greatly enhances the horizontal flow in the freezing period due to the terrain slope and the freezing-thawing process. Vertical migration is the mainly form of the soil moisture movement. It leads to that the soil-moisture content in the up-slope is higher than that in the down-slope. On the contrary, the soil-moisture content in the up-slope is lower than that in the down-slope during the melting period; 3) the main environmental factors which affect the slope-permafrost soil-moisture are elevation, soil texture, soil temperature and vegetation coverage. But there are differences in the impact factors of the soil moisture in different

  3. The Influence of Pb and Zn Contaminated soil on the Germination ...

    African Journals Online (AJOL)

    ADOWIE PERE

    www.bioline.org.br/ja. The Influence of Pb and Zn Contaminated soil on the Germination and Growth of ... of the periodic table such as aluminium, cadmium, zinc, chromium, copper ..... Remediation Division Robert S. Kerr. Environmental ...

  4. The transfer factors of I, Ba, Sr, Y and Zr from soil to leafy vegetables

    International Nuclear Information System (INIS)

    Luo Daling; Li Mianfeng; Weng Senhan; Wen Guanghao; Liu Xiaowei; Zhang Cunxiang; Zhang Zeng; Yu Junyue

    1996-01-01

    The transfer factors of I, Ba, Sr, Y and Zr from soil to leafy vegetables have been determined using method of radioisotope tracers and element content analysis. The effects of growth period, size of the vegetables, contents of the isotopes in the soil and other climatic factors on the transfer factors have also been studied

  5. Soil emanometry possibilities in assessment of different influences on environment

    International Nuclear Information System (INIS)

    Mojzes, A.

    2004-01-01

    Radioactive gas radon having origin in mineral composition of rocks is a dangerous radio-toxic element. This fact imposes a need of its detection and quantification with the aid of radon risk assessment in either geological basement or living rooms. Except for this it is possible to use the radon detection, thanks to its relatively simple measurement, for purposes of geological near-surface structure characterization because this object has also a direct influence on human environment. The goal of contribution is to present an attempt of utilization of field emanation survey (in complex with other geophysical survey methods) as means to closer and more detailed definition of that part of geological environment which is affected by both human activity of undermining and natural tectonic faults. In situ field measurements were carried out in the Homa Nitra Region whose environment is heavily burdened with such factors. (authors)

  6. INFLUENCE OF USUAL AND DUAL WHEELS ON SOIL PENETRATION RESISTANCE: THE GIS-APPROACH

    Directory of Open Access Journals (Sweden)

    Zhukov A. V.

    2015-12-01

    Full Text Available GIS-APPROACH application has allowed establishing that usual wheels of machine-tractor units carry out considerable influence on soil which exceeds visible borders of a track of wheels on the dimensions. This influence shows in augmentation of soil penetration resistance at 100-155 % in comparison with the control on depth of 0-10 cm and on 20-30 % on depth of 45-50 %. It is impossible to exclude that influence of wheels proceeds more deeply, than tests have been conducted. Critical for cultivated plants value of soil penetration resistance in 3 MPa under the influence of usual wheels of agricultural machinery comes nearer practically to a surface. Character of profile changes of hardness in various regions influences of wheels allows assuming the long season of a relaxation of soil for achievement of background values of soil penetration resistance. The further researches are necessary for an establishment of concrete indicators of dynamics. Negative influence of an overstocking does not confine only deterioration of conditions of growth of assemblages of rootlets of plants. Infringement of processes of moving of moisture in the soil, the accelerated evaporation and the slowed down processes of a filtration and an infiltration, destruction of modular frame, activization of erosive processes is possible. The understanding of these processes will give the chance volume understanding of real influence of running systems of machine-tractor devices on bedrock. Region intensive influence of dual wheels is circumscribed by the top soil layers (0-15 cm. The major feature of influence of dual wheels is absence of an overstocking above critical levels. It is impossible to exclude possible positive influence of moderate inspissations of soil under the influence of dual wheels for growth of agricultural crops and moisture conservation in soil. The cumulative negative effect on soil crossed vehicles traces is probable. The long season of a relaxation of

  7. Evaluation of soil saturation, soil chemistry, and early spring soil and air temperatures as risk factors in yellow-cedar decline.

    Science.gov (United States)

    D.V. D' Amore; P.E. Hennon

    2006-01-01

    Yellow-cedar (Callitropsis nootkatensis (D. Don) Oerst.) is a valuable tree species that is experiencing a widespread decline and mortality in southeast Alaska. This study evaluated the relative importance of several potential risk factors associated with yellow-cedar decline: soil saturation, soil aluminum (Al) toxicity or calcium (Ca) deficiency...

  8. Factors influencing quality of life in asthmatics

    DEFF Research Database (Denmark)

    Al-kalemji, Abir; Petersen, Karin Dam; Sørensen, Jan

    2013-01-01

    INTRODUCTION: The quality of life (QOL) in persons with asthma is reduced and different factors such as demography, asthma severity and psychiatric comorbidity play an influential role. However, little is known about the interplay of these factors. OBJECTIVE: To describe QOL in relation to asthma...

  9. Factors influencing e-commerce development in Serbia

    OpenAIRE

    Kalinić, Zoran; Ranković, Vladimir; Kalinić, Ljubina

    2016-01-01

    In this paper, an overview of current state of e-commerce development in Serbia is presented. Also, some important factors influencing e-commerce diffusion are discussed. The factors are divided into four groups: technical factors, which cover e- commerce telecommunication and logistics infrastructure; legal factors, i.e. necessary laws and regulations on e-commerce; economic factors, and psychological factors and local culture. The study showed very strong correlation between broadband inter...

  10. Influence of Tillage and Mulch on Soil Physical Properties and ...

    African Journals Online (AJOL)

    ... (M0); rice straw, (MRice); wheat straw, (MWheat); plastic sheet, (MPlastic) at 4 t ... Happy seeder and deep tillage along with plastic mulch have positive impact ... use efficiency and yield parameters by creating a favorable soil environment.

  11. Evaluation of soil microbial communities as influenced by crude oil ...

    African Journals Online (AJOL)

    sunny t

    2015-05-13

    May 13, 2015 ... Positive soil – microbes - plant interactions were observed. Key words: Species ... community composition based on groupings of fatty acids. (Broughton and ... microorganisms to adapt to changed environmental conditions ...

  12. Influence of soil drought stress on photosynthesis, carbohydrates ...

    African Journals Online (AJOL)

    USER

    2010-08-16

    Aug 16, 2010 ... and the ability of plant to adapt to drought stress. (Bulbotko, 1973; Atkinson et ... drought stress. In general, little is known about the effects of soil drought ..... fluorescence, water relations, and leaf abscisic acid. Plant Physiol.

  13. Soil microbial communities: Influence of geographic location and hydrocarbon pollutants

    CSIR Research Space (South Africa)

    Maila, MP

    2006-02-01

    Full Text Available The importance and relevance of the geographical origin of the soil sample and the hydrocarbons in determining the functional or species diversity within different bacterial communities was evaluated using the community level physiological profiles...

  14. Influence on the long-term fertilizing on radioactivity soils

    International Nuclear Information System (INIS)

    Grubisic, M.; Stevanovic, D.; Stojanovic, M.; Vuletic, V.; Pantelic, G.

    2007-01-01

    Researching in this work need to give the answer in which degree application the mineral fertilizers, especially phosphate, contribute to the contamination of a soil because of long-term continually fertilizing (35 years) and differences of adopting from the corn culture and wheat nursing in monocultures. Like control, it is made measuring activity of radionuclides of a soil on experimental variety where wasn't fertilizing during the making the experiment, separately for both cultures. Based on that it is given accent only on chronic contamination of a soil by radionuclides by application mineral fertilizers at once and transport in the system of soil of different biocenoses. Based on measuring activity 40K, 137Cs, 238U, 235U, 226Ra, 232Th, 212Pb it is fortified differences in concentration of the activity of radionuclides of uranium row between the samples of smonica, fertilized and non-fertilized in the longer period. (author) [sr

  15. Assessment of Relationships between Earthworms and Soil Abiotic and Biotic Factors as a Tool in Sustainable Agricultural

    Directory of Open Access Journals (Sweden)

    Radoslava Kanianska

    2016-09-01

    Full Text Available Earthworms are a major component of soil fauna communities. They influence soil chemical, biological, and physical processes and vice versa, their abundance and diversity are influenced by natural characteristics or land management practices. There is need to establish their characteristics and relations. In this study earthworm density (ED, body biomass (EB, and diversity in relation to land use (arable land—AL, permanent grasslands—PG, management, and selected abiotic (soil chemical, physical, climate related and biotic (arthropod density and biomass, ground beetle density, carabid density indicators were analysed at seven different study sites in Slovakia. On average, the density of earthworms was nearly twice as high in PG compared to AL. Among five soil types used as arable land, Fluvisols created the most suitable conditions for earthworm abundance and biomass. We recorded a significant correlation between ED, EB and soil moisture in arable land. In permanent grasslands, the main climate related factor was soil temperature. Relationships between earthworms and some chemical properties (pH, available nutrients were observed only in arable land. Our findings indicate trophic interaction between earthworms and carabids in organically managed arable land. Comprehensive assessment of observed relationships can help in earthworm management to achieve sustainable agricultural systems.

  16. Controlling factors in the dynamics of soil organic carbon from the region of Murcia

    International Nuclear Information System (INIS)

    Albaladejo, J.; Martinez-Mena, M.; Almagro, M.; Ruiz-navarro, A.; Ortiz, R.

    2009-01-01

    Sequestration and accumulation of C on the soil is a useful way to reduce the atmospheric concentration of CO 2 and to mitigate the climate change. The purpose of this study was to identify the key factors which determine the accumulation and permanence of CO on the soils of the Murcia Region. The study was arranged from data displayed on the Murcia Region Soils Map (1:100.000). The results showed that quantity of stored CO in the 30cm superficial soil is significantly different depending on soil uses, soil type, altitude and texture. One conclusion is that changes from natural vegetation to cultivated soil are the greatest cause of losses of CO of soil. The increasing of altitude and proportion of thin-silt + clay contributes to CE accumulation. In altitude, the speed of mineralization of organic materials decreases, and the thin particles stimulate the physical protection and the chemical stabilization of CO of soil. (Author) 8 refs.

  17. Clinical factors influencing participation in society after successful kidney transplantation

    NARCIS (Netherlands)

    van der Mei, S.F.; Groothoff, J.W.; van Sonderen, E.L.P.; van den Heuvel, W.J.A.; de Jong, P.E.; van Son, W.J.

    2006-01-01

    Background. Little information is available on the degree of actual social functioning after successful kidney transplantation. Moreover, information on factors that influence participation in social activities is scarce. The aim of this study was to examine the influence of clinical factors on

  18. Factors influencing selection of office furniture by corporations and universities

    Science.gov (United States)

    R. Bruce Anderson

    1976-01-01

    Evaluation of the factors that influence the selection of office furniture by large corporations and universities shows that quality, appearance, and purchase price have the most important influence on the purchase decision. The intended use of the furniture and the appearance of the furniture were the key factors in the purchase of wooden furniture.

  19. Factors Influencing Pregnancy Desires among HIV Positive Women ...

    African Journals Online (AJOL)

    Factors Influencing Pregnancy Desires among HIV Positive Women in Sibande District in Mpumalanga, South Africa. ... Gender and Behaviour ... The objective of the study is to present findings on factors influencing pregnancy desires amongst HIV positive women that have participated in Prevention of Mother to child ...

  20. Psychosocial Factors Influencing Attitudes Towards Internet Piracy ...

    African Journals Online (AJOL)

    In all a total of two hundred and fifty participants were drawn through accidental sampling technique for this study. Their age ranged between 19-48 ... In the same view, consumers ethnic group was not found to significantly influence attitude towards Internet piracy (F(3,246) = .404, P> .05). Reasons were given why the ...

  1. Perceptions of Child Caregivers About Factors Influencing ...

    African Journals Online (AJOL)

    Nutrition, health education and measles immunization are crucial components of preventive eye health services in the prevention of corneal blindness. This study explores ... The interplay between nutrition and corneal blindness was unknown to mothers in this study. The strong influence ... effectiveness and sustainability.

  2. Factors Influencing Degradation of Mercaptans by Thiobacillus ...

    African Journals Online (AJOL)

    Degradation of methylmercaptans by Thiobacillus thioparus TK-m was influenced by pH of the reaction medium. Ratios of headspace concentrations in empty vials and those of acidified buffer solutions were less than 1.0. 95% of the H2S was in headspace with the remaining 5% in solution upon acidification. The values for ...

  3. Community Factors Influencing Birth Spacing among Married ...

    African Journals Online (AJOL)

    The significance of community-level demographic and fertility norms, gender norms, economic prosperity, and family planning behaviors demonstrate the broad influence of community variables on birth spacing outcomes. This analysis highlights the importance of moving beyond individual and household-level ...

  4. Establishing principal soil quality parameters influencing earthworms in urban soils using bioassays

    International Nuclear Information System (INIS)

    Hankard, Peter K.; Bundy, Jacob G.; Spurgeon, David J.; Weeks, Jason M.; Wright, Julian; Weinberg, Claire; Svendsen, Claus

    2005-01-01

    Potential contamination at ex-industrial sites means that, prior to change of use, it will be necessary to quantify the extent of risks to potential receptors. To assess ecological hazards, it is often suggested to use biological assessment to augment chemical analyses. Here we investigate the potential of a commonly recommended bioassay, the earthworm reproduction test, to assess the status of urban contaminated soils. Sample points at all study sites had contaminant concentrations above the Dutch soil criteria Target Values. In some cases, the relevant Intervention Values were exceeded. Earthworm survival at most points was high, but reproduction differed significantly in soil from separate patches on the same site. When the interrelationships between soil parameters and reproduction were studied, it was not possible to create a good model of site soil toxicity based on single or even multiple chemical measurements of the soils. We thus conclude that chemical analysis alone is not sufficient to characterize soil quality and confirms the value of biological assays for risk assessment of potentially contaminated soils. - Bioassays must be applied for the risk assessment complexly-polluted sites to complement chemical analysis of soils

  5. Influence of Tillage and Mulch on Soil Physical Properties and ...

    African Journals Online (AJOL)

    User

    tillage along with plastic mulch have positive impact on soil physical properties, root growth, water use efficiency ... positive effects on crop yield (Gla & Kulig,. 2008). ... potash fertilizers were applied at 120, 100 and 60 .... 0-10. 1.57B. 1.57B. 1.57B. 1.8B. 1.7B. 1.8B. Tillage × Soil depth. CTInitial. 0-5 ...... (Brassica napus). Eur.

  6. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils

    Science.gov (United States)

    Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

    2015-01-01

    Abstract Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038

  7. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils.

    Science.gov (United States)

    Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

    2015-06-01

    Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline-alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation.

  8. Granulometry and moisture influence for in situ soil analysis by portable EDXRF

    International Nuclear Information System (INIS)

    Melquiades, Fabio L.; Bastos, Rodrigo O.; Biase, Gabriel E.V.; Parreira, Paulo S.; Appoloni, Carlos R.

    2010-01-01

    Full text: The objective of this work was to verify the granulometry and the moisture influence in results when soils and sediment samples are measured for identification and quantification of metal, on field, employing a portable Energy Dispersive X-Ray Fluorescence (PXRF) equipment. Calibration curves, calculated using 5 reference samples, were used for sensitivity determination. A sediment Standard Reference Material from IAEA was used to certificate the sensitivity values. The PXRF-LFNA02 equipment, consisting of an Ag mini X-ray Tube and a Si-PIN detector, was employed to accomplish the measurements. Soil samples were collected and dried for 24 h at 60 deg C before granulometry tests. Three grounding procedures were analyzed for granulometry influence evaluation: samples without any grounding; grounded for one minute using a porcelain mortar and pestle set, but without sieving; and grounded for one minute using a porcelain mortar and pestle set, and sieved (smaller than 125 mum particle size). The obtained concentration values for Ti, Fe and Zr, are equivalent for the samples grounded for one minute and the samples grounded and sieved. This result indicates that, for in situ analysis of this soil, it is sufficient to ground the dried sample before to measure. Moisture tests were performed by sampling the soil in situ and leaving the samples on aluminum recipients in open air, at sun, for distinct times, from 0 up to 2h. A reference sample, dried for 24h at 60 deg C, was measured as well in order to compare the results. The concentration values obtained for the samples dried during 30 minutes or 120 minutes at sun are equivalent. On the other hand, the concentration values obtained for the samples dried during 24 h are higher than the values obtained for the same samples dried at sun. Moisture influences the concentrations values in around 20%. Some considerations are performed indicating a methodology for correction of this factor by using the background under

  9. Granulometry and moisture influence for in situ soil analysis by portable EDXRF

    Energy Technology Data Exchange (ETDEWEB)

    Melquiades, Fabio L.; Bastos, Rodrigo O.; Biase, Gabriel E.V. [Universidade Estadual do Centro Oeste (UNICENTRO), Guarapuava, PR (Brazil). Dept. de Fisica; Parreira, Paulo S.; Appoloni, Carlos R. [Universidade Estadual de Londrina (DF/UEL), PR (Brazil). Dept. de Fisica

    2010-07-01

    Full text: The objective of this work was to verify the granulometry and the moisture influence in results when soils and sediment samples are measured for identification and quantification of metal, on field, employing a portable Energy Dispersive X-Ray Fluorescence (PXRF) equipment. Calibration curves, calculated using 5 reference samples, were used for sensitivity determination. A sediment Standard Reference Material from IAEA was used to certificate the sensitivity values. The PXRF-LFNA02 equipment, consisting of an Ag mini X-ray Tube and a Si-PIN detector, was employed to accomplish the measurements. Soil samples were collected and dried for 24 h at 60 deg C before granulometry tests. Three grounding procedures were analyzed for granulometry influence evaluation: samples without any grounding; grounded for one minute using a porcelain mortar and pestle set, but without sieving; and grounded for one minute using a porcelain mortar and pestle set, and sieved (smaller than 125 mum particle size). The obtained concentration values for Ti, Fe and Zr, are equivalent for the samples grounded for one minute and the samples grounded and sieved. This result indicates that, for in situ analysis of this soil, it is sufficient to ground the dried sample before to measure. Moisture tests were performed by sampling the soil in situ and leaving the samples on aluminum recipients in open air, at sun, for distinct times, from 0 up to 2h. A reference sample, dried for 24h at 60 deg C, was measured as well in order to compare the results. The concentration values obtained for the samples dried during 30 minutes or 120 minutes at sun are equivalent. On the other hand, the concentration values obtained for the samples dried during 24 h are higher than the values obtained for the same samples dried at sun. Moisture influences the concentrations values in around 20%. Some considerations are performed indicating a methodology for correction of this factor by using the background under

  10. Influence of ageing on zinc bioavailability in soils

    Energy Technology Data Exchange (ETDEWEB)

    Lock, K.; Janssen, C.R

    2003-12-01

    Currently, soil quality criteria or soil risk assessments of metals are based on laboratory toxicity tests which are carried out in soils freshly spiked with metal salts. With these data, species sensitivity distributions are fitted, from which hazardous concentrations and predicted no effect concentrations are derived. However, due to long-term processes, called ageing, soil metal availability decreases with time. Here we show that pH is the most important parameter determining the effect of ageing on zinc partitioning in soils, with the effect of ageing becoming more important with increasing pH. Furthermore, zinc bioavailability, expressed as the internal zinc concentrations in red clover (Trifolium pratense) is closely related to pore water zinc concentration. In addition, there is a clear dose-response relationship between the survival of the earthworm Eisenia fetida and the calcium chloride-extracted zinc fraction. These results indicate that zinc partitioning can be used to predict zinc bioavailability to terrestrial organisms. However, the use of spiked soils in toxicity assays can result in an over-estimation of the effects of zinc, especially at a high pH. - Zn ageing is affected by pH, while Zn partitioning can be used to predict its bioavailability.

  11. The influence of land use on soil organic carbon and nitrogen content and redox potential

    DEFF Research Database (Denmark)

    Kusliene, Gedrime

    2010-01-01

    different farming systems (conventional and organic) as well as abandoned lands. We choose the plants of two botanical species (Poaceae and Fabaceae) in organic and conventional farming systems as well as abandoned lands. Experimental results show that the best soil organic matter status according...... to the investigated indexes is in the soils of conventional and orgaic farming systems occupied with mixtures of Poaceae and Fabaceae and the worst - in the soils of abandoned Poaceae meadowa. In the abandoned lands, Fabaceae (galega) had better influence on soil organic matter status than Poaceae....

  12. Influence of Rice Husk Ash and Clay in Stabilization of Silty Soils Using Cement

    OpenAIRE

    Widjajakusuma Jack; Winata Hendo

    2017-01-01

    Soil stabilization is needed to enhance the strength of the soil. One popular method of soil stabilization is using cement. Due to the environmental issue, it is a need to reduce the application of cement and/or to replace partially the cement with other environmental-friendly compounds. One of these compounds is rice husk ash (RSA), which is agricultural wastes. The objective of this paper is to study the influence of RSA and clay as partial replacement to cement in soil stabilization of sil...

  13. Influencing Factors and Simplified Model of Film Hole Irrigation

    Directory of Open Access Journals (Sweden)

    Yi-Bo Li

    2017-07-01

    Full Text Available Film hole irrigation is an advanced low-cost and high-efficiency irrigation method, which can improve water conservation and water use efficiency. Given its various advantages and potential applications, we conducted a laboratory study to investigate the effects of soil texture, bulk density, initial soil moisture, irrigation depth, opening ratio (ρ, film hole diameter (D, and spacing on cumulative infiltration using SWMS-2D. We then proposed a simplified model based on the Kostiakov model for infiltration estimation. Error analyses indicated SWMS-2D to be suitable for infiltration simulation of film hole irrigation. Additional SWMS-2D-based investigations indicated that, for a certain soil, initial soil moisture and irrigation depth had the weakest effects on cumulative infiltration, whereas ρ and D had the strongest effects on cumulative infiltration. A simplified model with ρ and D was further established, and its use was then expanded to different soils. Verification based on seven soil types indicated that the established simplified double-factor model effectively estimates cumulative infiltration for film hole irrigation, with a small mean average error of 0.141–2.299 mm, a root mean square error of 0.177–2.722 mm, a percent bias of −2.131–1.479%, and a large Nash–Sutcliffe coefficient that is close to 1.0.

  14. Factors influencing the prevalence of primary dysmenorrhoea ...

    African Journals Online (AJOL)

    ... of primary dysmenorrhoea amongst Abia State university medical students, South ... its impact on school and social activities and the students' management strategies. ... is high, and not consistently associated with demographic risk factors.

  15. Determination of Mucosal Secretory Factors that Influence ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Understanding the complex factors that can lead to HIV infection is crucial to addressing the problem among vulnerable ... Related content ... Policy in Focus publishes a special issue profiling evidence to empower women in the labour market.

  16. Is Subjective Status Influenced by Psychosocial Factors?

    OpenAIRE

    Lundberg, Johanna; Kristenson, Margareta

    2008-01-01

    Objective Associations between subjective status and health are still relatively unexplored. This study aimed at testing whether subjective status is uniquely confounded by psychosocial factors compared to objective status, and what factors that may predict subjective status. Design A cross-sectional analysis of a population-based, random sample of 795 middle-aged men and women from the southeast of Sweden. Questionnaires included subjective status, objective measures of socioeconomic status,...

  17. Modification of "1"3"7Cs transfer to rape (Brassica napus L.) phytomass under the influence of soil microorganisms

    International Nuclear Information System (INIS)

    Pareniuk, O.; Shavanova, K.; Laceby, J.P.; Illienko, V.; Tytova, L.; Levchuk, S.; Gudkov, I.; Nanba, K.

    2015-01-01

    After nuclear accidents, such as those experienced in Chernobyl and Fukushima, microorganisms may help purify contaminated soils by changing the mobility of radionuclides and their availability for plants by altering the physical and chemical properties of the substrate. Here, using model experiments with quartz sand as a substrate we investigate the influence of microorganisms on "1"3"7Cs transfer from substrate to plants. The highest transition of "1"3"7Cs from substrate to plants (50% increase compared to the control) was observed after Brassica napus L. seeds were inoculated by Azotobacter chroococcum. The best results for reducing the accumulation of "1"3"7Cs radionuclides (30% less) were noted after the inoculation by Burkholderia sp.. Furthermore, Bacillus megaterium demonstrated an increased ability to accumulate "1"3"7Cs. This research improves our prediction of the behavior of radionuclides in soil and may contribute towards new, microbiological countermeasures for soil remediation following nuclear accidents. - Highlights: • Representatives of soil bacteria can alter "1"3"7Cs soil-to-plant transfer factor. • This ability does not depend on the localization of bacteria on the root surface. • Selection of bacteria to increase or decrease the "1"3"7Cs transfer factor is possible.

  18. Factors that influence peripheral nerve regeneration

    DEFF Research Database (Denmark)

    Krarup, Christian; Archibald, Simon J; Madison, Roger D

    2002-01-01

    median nerve lesions (n = 46) in nonhuman primates over 3 to 4 years, a time span comparable with such lesions in humans. Nerve gap distances of 5, 20, or 50mm were repaired with nerve grafts or collagen-based nerve guide tubes, and three electrophysiological outcome measures were followed: (1) compound...... muscle action potentials in the abductor pollicis brevis muscle, (2) the number and size of motor units in reinnervated muscle, and (3) compound sensory action potentials from digital nerve. A statistical model was used to assess the influence of three variables (repair type, nerve gap distance, and time...... to earliest muscle reinnervation) on the final recovery of the outcome measures. Nerve gap distance and the repair type, individually and concertedly, strongly influenced the time to earliest muscle reinnervation, and only time to reinnervation was significant when all three variables were included as outcome...

  19. Soil enzyme dynamics in chlorpyrifos-treated soils under the influence of earthworms.

    Science.gov (United States)

    Sanchez-Hernandez, Juan C; Notario Del Pino, J; Capowiez, Yvan; Mazzia, Christophe; Rault, Magali

    2018-01-15

    Earthworms contribute, directly and indirectly, to contaminant biodegradation. However, most of bioremediation studies using these annelids focus on pollutant dissipation, thus disregarding the health status of the organism implied in bioremediation as well as the recovery of indicators of soil quality. A microcosm study was performed using Lumbricus terrestris to determine whether earthworm density (2 or 4individuals/kg wet soil) and the time of exposure (1, 2, 6, 12, and 18wk) could affect chlorpyrifos persistence in soil initially treated with 20mg active ingredientkg -1 wet soil. Additionally, selected earthworm biomarkers and soil enzyme activities were measured as indicators of earthworm health and soil quality, respectively. After an 18-wk incubation period, no earthworm was killed by the pesticide, but clear signs of severe intoxication were detected, i.e., 90% inhibition in muscle acetylcholinesterase and carboxylesterase (CbE) activities. Unexpectedly, the earthworm density had no significant impact on chlorpyrifos dissipation rate, for which the measured half-life ranged between 30.3d (control soils) and 44.5d (low earthworm density) or 36.7d (high earthworm density). The dynamic response of several soil enzymes to chlorpyrifos exposure was examined calculating the geometric mean and the treated-soil quality index, which are common enzyme-based indexes of microbial functional diversity. Both indexes showed a significant and linear increase of the global enzyme response after 6wk of chlorpyrifos treatment in the presence of earthworms. Examination of individual enzymes revealed that soil CbE activity could decrease chlorpyrifos-oxon impact upon the rest of enzyme activities. Although L. terrestris was found not to accelerate chlorpyrifos dissipation, a significant increase in the activity of soil enzyme activities was achieved compared with earthworm-free, chlorpyrifos-treated soils. Therefore, the inoculation of organophosphorus-contaminated soils with L

  20. Bioavailability and soil-to-plant transfer factors as indicators of potentially toxic element contamination in agricultural soils

    International Nuclear Information System (INIS)

    Adamo, Paola; Iavazzo, Pietro; Albanese, Stefano; Agrelli, Diana; De Vivo, Benedetto; Lima, Annamaria

    2014-01-01

    Soil pollution in agricultural lands poses a serious threat to food safety, and suggests the need for consolidated methods providing advisory indications for soil management and crop production. In this work, the three-step extraction procedure developed by the EU Measurement and Testing Programme and two soil-to-plant transfer factors (relative to total and bioavailable concentration of elements in soil) were applied on polluted agricultural soils from southern Italy to obtain information on the retention mechanisms of metals in soils and on their level of translocation to edible vegetables. The study was carried out in the Sarno river plain of Campania, an area affected by severe environmental degradation potentially impacting the health of those consuming locally produced vegetables. Soil samples were collected in 36 locations along the two main rivers flowing into the plain. In 11 sites, lettuce plants were collected at the normal stage of consumption. According to Italian environmental law governing residential soils, and on the basis of soil background reference values for the study area, we found diffuse pollution by Be, Sn and Tl, of geogenic origin, Cr and Cu from anthropogenic sources such as tanneries and intensive agriculture, and more limited pollution by Pb, Zn and V. It was found that metals polluting soils as a result of human activities were mainly associated to residual, oxidizable and reducible phases, relatively immobile and only potentially bioavailable to plants. By contrast, the essential elements Zn and Cu showed a tendency to become more readily mobile and bioavailable as their total content in soil increased and were more easily transported to the edible parts of lettuce than other pollutants. According to our results, current soil pollution in the studied area does not affect the proportion of metals taken up by lettuce plants and there is a limited health risk incurred. - Highlights: • Soil pollution in an intensively farmed area of

  1. Bioavailability and soil-to-plant transfer factors as indicators of potentially toxic element contamination in agricultural soils

    Energy Technology Data Exchange (ETDEWEB)

    Adamo, Paola, E-mail: paola.adamo@unina.it [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); Iavazzo, Pietro [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); Albanese, Stefano [Dipartimento di Scienze della Terra, dell' Ambiente e delle Risorse, Università di Napoli Federico II, Via Mezzocannone 8, 80134 Napoli (Italy); Agrelli, Diana [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); De Vivo, Benedetto; Lima, Annamaria [Dipartimento di Scienze della Terra, dell' Ambiente e delle Risorse, Università di Napoli Federico II, Via Mezzocannone 8, 80134 Napoli (Italy)

    2014-12-01

    Soil pollution in agricultural lands poses a serious threat to food safety, and suggests the need for consolidated methods providing advisory indications for soil management and crop production. In this work, the three-step extraction procedure developed by the EU Measurement and Testing Programme and two soil-to-plant transfer factors (relative to total and bioavailable concentration of elements in soil) were applied on polluted agricultural soils from southern Italy to obtain information on the retention mechanisms of metals in soils and on their level of translocation to edible vegetables. The study was carried out in the Sarno river plain of Campania, an area affected by severe environmental degradation potentially impacting the health of those consuming locally produced vegetables. Soil samples were collected in 36 locations along the two main rivers flowing into the plain. In 11 sites, lettuce plants were collected at the normal stage of consumption. According to Italian environmental law governing residential soils, and on the basis of soil background reference values for the study area, we found diffuse pollution by Be, Sn and Tl, of geogenic origin, Cr and Cu from anthropogenic sources such as tanneries and intensive agriculture, and more limited pollution by Pb, Zn and V. It was found that metals polluting soils as a result of human activities were mainly associated to residual, oxidizable and reducible phases, relatively immobile and only potentially bioavailable to plants. By contrast, the essential elements Zn and Cu showed a tendency to become more readily mobile and bioavailable as their total content in soil increased and were more easily transported to the edible parts of lettuce than other pollutants. According to our results, current soil pollution in the studied area does not affect the proportion of metals taken up by lettuce plants and there is a limited health risk incurred. - Highlights: • Soil pollution in an intensively farmed area of

  2. Influence of organic components onto state of radioactive strontium in soils

    International Nuclear Information System (INIS)

    Sokolik, G.A.; Ovsyannikova, S.V.; Cherevko, E.S.; Rubinchik, S.Ya.

    2005-01-01

    Influence of soil organic components onto radioactive strontium mobility in the soil medium has been analyzed. Distribution of the Sr 90 between various organic fractions of soils having different quantitative and qualitative composition of organic matter has been studied. The samples of mineral and organic soils contaminated by radionuclides of Chernobyl origin were used as the objects of investigation. Fulvic- and humic-acid fractions differed in solubility and mobility in a soil medium have been separated. Differentiation of soils on the Sr 90 mobility in accordance with portion of radionuclide in the immobile organic fractions has been fulfilled. New types of organic and organomineral additives decreased mobility and biological availability of the Sr 90 have been suggested on a base of obtained data. (authors)

  3. Influence Of Soil Type On Yield And Quality Of Different Apple Cultivars

    Directory of Open Access Journals (Sweden)

    Alina Viorica ILIE

    2017-05-01

    Full Text Available The objective of this study was to determine influence of different soil type on apple yield and quality. To investigate the variation in fruit quality, apples were harvested at commercial maturity on two different soil type. The investigations was conducted in experimental apple orchards located in Focsani region on two different soil type: luvic  brown typical and  luvic brown pseudogleizate. Fruits of Jonathan and Golden Delicios cultivars were tested for color, soluble solids content, total acidity, ascorbic acid, anthocyanins content and chlorophyls content with specific analytrical methods. At harvest yield, dry matter, soluble solids content, ascorbic acid and acidity were affected by soil type. In this study, no significant soil effect was found on color, anthocyanins and chlorophyll fruit content. The results obtained in this study suggest that luvic brown pseudogleizate soil leading to increased yields and enhanced fruit quality.

  4. Factors Influencing Organization Adoption Decision On Cloud Computing

    OpenAIRE

    Ailar Rahimli

    2013-01-01

    Cloud computing is a developing field, using by organization that require to computing resource to provide the organizational computing needs. The goal of this research is evaluate the factors that influence on organization decision to adopt the cloud computing in Malaysia. Factors that relate to cloud computing adoption that include : need for cloud computing, cost effectiveness, security effectiveness of cloud computing and reliability. This paper evaluated the factors that influence on ado...

  5. Factors influencing societal response of nanotechnology : an expert stakeholder analysis

    OpenAIRE

    Gupta, N.; Fischer, A.R.H.; Lans, van der, I.A.; Frewer, L.J.

    2012-01-01

    Nanotechnology can be described as an emerging technology and, as has been the case with other emerging technologies such as genetic modification, different socio-psychological factors will potentially influence societal responses to its development and application. These factors will play an important role in how nanotechnology is developed and commercialised. This article aims to identify expert opinion on factors influencing societal response to applications of nanotechnology. Structured i...

  6. Factors influencing societal response of nanotechnology: an expert stakeholder analysis

    OpenAIRE

    Gupta, Nidhi; Fischer, Arnout R. H.; van der Lans, Ivo A.; Frewer, Lynn J.

    2012-01-01

    Nanotechnology can be described as an emerging technology and, as has been the case with other emerging technologies such as genetic modification, different socio-psychological factors will potentially influence societal responses to its development and application. These factors will play an important role in how nanotechnology is developed and commercialised. This article aims to identify expert opinion on factors influencing societal response to applications of nanotechnology. Structured i...

  7. Influence Factors of the Economic Development Level Across European Countries

    OpenAIRE

    Diana Ioana POPA

    2016-01-01

    The economic development level of a country refers to the measure of the progress in an economy that could be measured, especially through GDP or GDP per capita. The level of these indicators can be influenced by many factors as a large scale, from social and economical to environmental and government policies factors. The paper aims to investigate some of these influence factors of the economic development level, represented in this case by GDP per capita, across European countries in the...

  8. Additional factors influencing resident satisfaction and dissatisfaction

    Directory of Open Access Journals (Sweden)

    Jalal SR

    2017-11-01

    Full Text Available Seyed Ramin Jalal, Abdirahman Osman, Saeed Azizi  Faculty of Medicine, St George’s Hospital Medical School, London, UK We have read the recent review article by Kahn et al1 with great interest. The original