The effect of cropping sequence on the crop yield and nutrient availability

International Nuclear Information System (INIS)

Sisworo, W.H.; Rasjid, H.

1988-01-01

A two seasons field experiment was conducted to study the carry over effect of previous crop on the succeeding crop yield and plan nutrient (N and P) availability. The experiment consisted of eight treatments were arranged in a randomized block design with six resplications. Cropping sequence was studied that was soybean followed by corn and a continuous corn system. The effect of added P to the previous crops on the succeeding crops yield was also observed. Labelled fertilizer were used in the experiment to measure dinitrogen fixation of two soybean varieties and the amount of available nutrient in the soil by using isotopic dilution technique. The result obtained showed that corn yield was significantly influenced by cropping sequence, but available nutrient was not. Corn grown after soybean produced about 22 percent more grain than those of the continuous corn system. The phosphorus applied to the first season crops increased significantly the succeeding corn yield. The highest amount of accumulation in soybean was 81 kg N/h, around 40 percent of the amount was obtained through fixation. (authors). 19 refs.; 8 tabs

Convenience stores are the key food environment influence on nutrients available from household food supplies in Texas Border Colonias.

Science.gov (United States)

Sharkey, Joseph R; Dean, Wesley R; Nalty, Courtney C; Xu, Jin

2013-01-17

Few studies have focused on the relationship between the retail food environment and household food supplies. This study examines spatial access to retail food stores, food shopping habits, and nutrients available in household food supplies among 50 Mexican-origin families residing in Texas border colonias. The design was cross-sectional; data were collected in the home March to June 2010 by promotora-researchers. Ground-truthed methods enumerated traditional (supercenters, supermarkets, grocery stores), convenience (convenience stores and food marts), and non-traditional (dollar stores, discount stores) retail food stores. Spatial access was computed using the network distance from each participant's residence to each food store. Data included survey data and two household food inventories (HFI) of the presence and amount of food items in the home. The Spanish language interviewer-administered survey included demographics, transportation access, food purchasing, food and nutrition assistance program participation, and the 18-item Core Food Security Module. Nutrition Data Systems for Research (NDS-R) was used to calculate HFI nutrients. Adult equivalent adjustment constants (AE), based on age and gender calorie needs, were calculated based on the age- and gender composition of each household and used to adjust HFI nutrients for household composition. Data were analyzed using bivariate analysis and linear regression models to determine the association of independent variables with the availability of each AE-adjusted nutrient. Regression models showed that households in which the child independently purchased food from a convenience store at least once a week had foods and beverages with increased amounts of total energy, total fat, and saturated fat. A greater distance to the nearest convenience store was associated with reduced amounts of total energy, vitamin D, total sugar, added sugar, total fat, and saturated fat. Participation in the National School Lunch

Convenience stores are the key food environment influence on nutrients available from household food supplies in Texas Border Colonias

Directory of Open Access Journals (Sweden)

Sharkey Joseph R

2013-01-01

Full Text Available Abstract Background Few studies have focused on the relationship between the retail food environment and household food supplies. This study examines spatial access to retail food stores, food shopping habits, and nutrients available in household food supplies among 50 Mexican-origin families residing in Texas border colonias. Methods The design was cross-sectional; data were collected in the home March to June 2010 by promotora-researchers. Ground-truthed methods enumerated traditional (supercenters, supermarkets, grocery stores, convenience (convenience stores and food marts, and non-traditional (dollar stores, discount stores retail food stores. Spatial access was computed using the network distance from each participant’s residence to each food store. Data included survey data and two household food inventories (HFI of the presence and amount of food items in the home. The Spanish language interviewer-administered survey included demographics, transportation access, food purchasing, food and nutrition assistance program participation, and the 18-item Core Food Security Module. Nutrition Data Systems for Research (NDS-R was used to calculate HFI nutrients. Adult equivalent adjustment constants (AE, based on age and gender calorie needs, were calculated based on the age- and gender composition of each household and used to adjust HFI nutrients for household composition. Data were analyzed using bivariate analysis and linear regression models to determine the association of independent variables with the availability of each AE-adjusted nutrient. Results Regression models showed that households in which the child independently purchased food from a convenience store at least once a week had foods and beverages with increased amounts of total energy, total fat, and saturated fat. A greater distance to the nearest convenience store was associated with reduced amounts of total energy, vitamin D, total sugar, added sugar, total fat, and saturated

The influence of nutrient and water availability on carbohydrate storage in loblolly pine

Science.gov (United States)

K.H. Ludovici; H.L. Allen; T.J. Albaugh; P.M. Dougherty

2002-01-01

We quantified the effects of nutrient and water availability on monthly whole-tree carbohydrate budgets and determined allocation patterns of storage carbohydrates in loblolly pine (Pinus taeda) to test site resource impacts on internal carbon (C) storage. A factorial combination of two nutrient and two irrigation treatments were imposed on a 7-year...

Effect of soil carbohydrates on nutrient availability in natural forests and cultivated lands in Sri Lanka

Science.gov (United States)

Ratnayake, R. R.; Seneviratne, G.; Kulasooriya, S. A.

2013-05-01

Carbohydrates supply carbon sources for microbial activities that contribute to mineral nutrient production in soil. Their role on soil nutrient availability has not yet been properly elucidated. This was studied in forests and cultivated lands in Sri Lanka. Soil organic matter (SOM) fractions affecting carbohydrate availability were also determined. Soil litter contributed to sugars of plant origin (SPO) in croplands. The negative relationship found between clay bound organic matter (CBO) and glucose indicates higher SOM fixation in clay that lower its availability in cultivated lands. In forests, negative relationships between litter and sugars of microbial origin (SMO) showed that litter fuelled microbes to produce sugars. Fucose and glucose increased the availability of Cu, Zn and Mn in forests. Xylose increased Ca availability in cultivated lands. Arabinose, the main carbon source of soil respiration reduced the P availability. This study showed soil carbohydrates and their relationships with mineral nutrients could provide vital information on the availability of limiting nutrients in tropical ecosystems.

Probiotics for Plants? Growth Promotion by the Entomopathogenic Fungus Beauveria bassiana Depends on Nutrient Availability.

Science.gov (United States)

Tall, Susanna; Meyling, Nicolai V

2018-03-28

Cultivation of crops requires nutrient supplements which are costly and impact the environment. Furthermore, global demands for increased crop production call for sustainable solutions to increase yield and utilize resources such as nutrients more effectively. Some entomopathogenic fungi are able to promote plant growth, but studies over such effects have been conducted under optimal conditions where nutrients are abundantly available. We studied the effects of Beauveria bassiana (strain GHA) seed treatment on the growth of maize (Zea mays) at high and low nutrient conditions during 6 weeks in greenhouse. As expected, B. bassiana seed treatment increased plant growth, but only at high nutrient conditions. In contrast, the seed treatment did not benefit plant growth at low nutrient conditions where the fungus potentially constituted a sink and tended to reduce plant growth. The occurrence of endophytic B. bassiana in experimental plant tissues was evaluated by PCR after 6 weeks, but B. bassiana was not documented in any of the above-ground plant tissues indicating that the fungus-plant interaction was independent of endophytic establishment. Our results suggest that B. bassiana seed treatment could be used as a growth promoter of maize when nutrients are abundantly available, while the fungus does not provide any growth benefits when nutrients are scarce.

Food crop production, nutrient availability, and nutrient intakes in Bangladesh: exploring the agriculture-nutrition nexus with the 2010 Household Income and Expenditure Survey.

Science.gov (United States)

Fiedler, John L

2014-12-01

Systematic collection of national agricultural data has been neglected in many low- and middle-income countries for the past 20 years. Commonly conducted nationally representative household surveys collect substantial quantities of highly underutilized food crop production data. To demonstrate the potential usefulness of commonly available household survey databases for analyzing the agriculture-nutrition nexus. Using household data from the 2010 Bangladesh Household Income and Expenditure Survey, the role and significance of crop selection, area planted, yield, nutrient production, and the disposition of 34 food crops in affecting the adequacy of farming households' nutrient availability and nutrient intake status are explored. The adequacy of each farming household's available energy, vitamin A, calcium, iron, and zinc and households' apparent intakes and intake adequacies are estimated. Each household's total apparent nutrient intake adequacies are estimated, taking into account the amount of each crop that households consume from their own production, together with food purchased or obtained from other sources. Even though rice contains relatively small amounts of micronutrients, has relatively low nutrient density, and is a relatively poor source of nutrients compared with what other crops can produce on a given tract of land, because so much rice is produced in Bangladesh, it is the source of 90% of the total available energy, 85% of the zinc, 67% of the calcium, and 55% of the iron produced by the agricultural sector. The domination of agriculture and diet by rice is a major constraint to improving nutrition in Bangladesh. Simple examples of how minor changes in the five most common cropping patterns could improve farming households' nutritional status are provided. Household surveys' agricultural modules can provide a useful tool for better understanding national nutrient production realities and possibilities.

Recovering greater fungal diversity from pristine and diesel fuel contaminated Sub-Antarctic soil through cultivation using a high and a novel low nutrient approach

Directory of Open Access Journals (Sweden)

Belinda Carlene Ferrari

2011-11-01

Full Text Available Novel cultivation strategies for bacteria are widespread and are well described for recovering greater diversity from the hitherto unculturable majority. While similar approaches have not been demonstrated for fungi it has been suggested that of the 1.5 million estimated species less than 5% have been recovered into pure culture. Fungi are known to be involved in many degradative processes, including the breakdown of hydrocarbons, and it has been speculated that in Polar Regions they contribute significantly to bioremediation of soils contaminated with hydrocarbons. Given the biotechnological potential of fungi there is a need to increase efforts for greater species recovery, particularly from extreme environments such as sub-Antarctic Macquarie Island. In this study, like the hitherto unculturable bacteria, high concentrations of nutrients selected for predominantly different species to that recovered using low nutrient media. By combining both approaches to cultivation from contaminated and non-contaminated soils, 99 fungal species were recovered, including 42 yet unidentified species, several of which were isolated from soils containing high concentrations of diesel fuel. These novel species will now be characterized for their potential role in hydrocarbon degradation.

Convenience stores are the key food environment influence on nutrients available from household food supplies in Texas Border Colonias

Science.gov (United States)

2013-01-01

Background Few studies have focused on the relationship between the retail food environment and household food supplies. This study examines spatial access to retail food stores, food shopping habits, and nutrients available in household food supplies among 50 Mexican-origin families residing in Texas border colonias. Methods The design was cross-sectional; data were collected in the home March to June 2010 by promotora-researchers. Ground-truthed methods enumerated traditional (supercenters, supermarkets, grocery stores), convenience (convenience stores and food marts), and non-traditional (dollar stores, discount stores) retail food stores. Spatial access was computed using the network distance from each participant’s residence to each food store. Data included survey data and two household food inventories (HFI) of the presence and amount of food items in the home. The Spanish language interviewer-administered survey included demographics, transportation access, food purchasing, food and nutrition assistance program participation, and the 18-item Core Food Security Module. Nutrition Data Systems for Research (NDS-R) was used to calculate HFI nutrients. Adult equivalent adjustment constants (AE), based on age and gender calorie needs, were calculated based on the age- and gender composition of each household and used to adjust HFI nutrients for household composition. Data were analyzed using bivariate analysis and linear regression models to determine the association of independent variables with the availability of each AE-adjusted nutrient. Results Regression models showed that households in which the child independently purchased food from a convenience store at least once a week had foods and beverages with increased amounts of total energy, total fat, and saturated fat. A greater distance to the nearest convenience store was associated with reduced amounts of total energy, vitamin D, total sugar, added sugar, total fat, and saturated fat. Participation in

The influence of soil properties and nutrients on conifer forest growth in Sweden, and the first steps in developing a nutrient availability metric

Science.gov (United States)

Van Sundert, Kevin; Horemans, Joanna A.; Stendahl, Johan; Vicca, Sara

2018-06-01

The availability of nutrients is one of the factors that regulate terrestrial carbon cycling and modify ecosystem responses to environmental changes. Nonetheless, nutrient availability is often overlooked in climate-carbon cycle studies because it depends on the interplay of various soil factors that would ideally be comprised into metrics applicable at large spatial scales. Such metrics do not currently exist. Here, we use a Swedish forest inventory database that contains soil data and tree growth data for > 2500 forests across Sweden to (i) test which combination of soil factors best explains variation in tree growth, (ii) evaluate an existing metric of constraints on nutrient availability, and (iii) adjust this metric for boreal forest data. With (iii), we thus aimed to provide an adjustable nutrient metric, applicable for Sweden and with potential for elaboration to other regions. While taking into account confounding factors such as climate, N deposition, and soil oxygen availability, our analyses revealed that the soil organic carbon concentration (SOC) and the ratio of soil carbon to nitrogen (C : N) were the most important factors explaining variation in normalized (climate-independent) productivity (mean annual volume increment - m3 ha-1 yr-1) across Sweden. Normalized forest productivity was significantly negatively related to the soil C : N ratio (R2 = 0.02-0.13), while SOC exhibited an empirical optimum (R2 = 0.05-0.15). For the metric, we started from a (yet unvalidated) metric for constraints on nutrient availability that was previously developed by the International Institute for Applied Systems Analysis (IIASA - Laxenburg, Austria) for evaluating potential productivity of arable land. This IIASA metric requires information on soil properties that are indicative of nutrient availability (SOC, soil texture, total exchangeable bases - TEB, and pH) and is based on theoretical considerations that are also generally valid for nonagricultural ecosystems

Effect of light and nutrient availability on the release of dissolved organic carbon (DOC) by Caribbean turf algae.

Science.gov (United States)

Mueller, Benjamin; den Haan, Joost; Visser, Petra M; Vermeij, Mark J A; van Duyl, Fleur C

2016-03-22

Turf algae increasingly dominate benthic communities on coral reefs. Given their abundance and high dissolved organic carbon (DOC) release rates, turf algae are considered important contributors to the DOC pool on modern reefs. The release of photosynthetically fixed carbon as DOC generally, but not always, increases with increased light availability. Nutrient availability was proposed as an additional factor to explain these conflicting observations. To address this proposed but untested hypothesis, we documented the interactive contributions of light and nutrient availability on the release of DOC by turf algae. DOC release rates and oxygen production were quantified in incubation experiments at two light levels (full and reduced light) and two nutrient treatments (natural seawater and enriched seawater). In natural seawater, DOC release at full light was four times higher than at reduced light. When nutrients were added, DOC release rates at both light levels were similar to the natural seawater treatment at full light. Our results therefore show that low light in combination with low nutrient availability reduces the release of DOC by turf algae and that light and nutrient availability interactively determine DOC release rates by this important component of Caribbean reef communities.

Soil nutrient assessment for urban ecosystems in Hubei, China.

Directory of Open Access Journals (Sweden)

Zhi-Guo Li

Full Text Available Recent urban landscape vegetation surveys conducted in many cities in China identified numerous plant nutrient deficiencies, especially in newly developed cities. Soil nutrients and soil nutrient management in the cities of Hubei province have not received adequate attention to date. The aims of this study were to characterize the available nutrients of urban soils from nine cities in Hubei province, China, and to assess how soil nutrient status is related to land use type and topography. Soil nutrients were measured in 405 sites from 1,215 soil samples collected from four land use types (park, institutional [including government building grounds, municipal party grounds, university grounds, and garden city institutes], residential, and roadside verges and three topographies (mountainous [142-425 m a.s.l], hilly [66-112 m a.s.l], and plain [26-30 m a.s.l]. Chemical analyses showed that urban soils in Hubei had high pH and lower soil organic matter, available nitrogen (N, available phosphorus (P, and available boron (B concentrations than natural soils. Nutrient concentrations were significantly different among land use types, with the roadside and residential areas having greater concentrations of calcium (Ca, sulfur (S, copper (Cu, manganese (Mn, and zinc (Zn that were not deficient against the recommended ranges. Topographic comparisons showed statistically significant effects for 8 of the 11 chemical variables (p < 0.05. Concentrations of N, Ca, Mg, S, Cu, and Mn in plain cities were greater than those in mountainous cities and show a negative correlation with city elevation. These results provide data on urban soils characteristics in land use types and topography, and deliver significant information for city planners and policy makers.

Ultrastructural biomarkers in symbiotic algae reflect the availability of dissolved inorganic nutrients and particulate food to the reef coral holobiont

Directory of Open Access Journals (Sweden)

Sabrina eRosset

2015-11-01

Full Text Available Reef building corals associated with symbiotic algae (zooxanthellae can access environmental nutrients from different sources, most significantly via the uptake of dissolved inorganic nutrients by the algal symbiont and heterotrophic feeding of the coral host. Climate change is expected to alter the nutrient environment in coral reefs with the potential to benefit or disturb coral reef resilience. At present, the relative importance of the two major nutrient sources is not well understood, making predictions of the responses of corals to changes in their nutrient environment difficult. Therefore, we have examined the long-term effects of the availability of different concentrations of dissolved inorganic nutrients and of nutrients in particulate organic form on the model coral Euphyllia paradivisa. Coral and algal biomass showed a significantly stronger increase in response to elevated levels of dissolved inorganic nutrients as compared to the supply with particulate food. Also, changes in the zooxanthellae ultrastructure, determined by transmission electron microscopy (TEM, were mostly driven by the availability of dissolved inorganic nutrients under the present experimental conditions. The larger size of symbiont cells, their increased accumulation of lipid bodies, a higher number of starch granules and the fragmentation of their accumulation body could be established as reliable biomarkers of low availability of dissolved inorganic nutrients to the coral holobiont.

Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

Directory of Open Access Journals (Sweden)

Sarah E Pabian

Full Text Available Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

Nutrient enrichment increases mortality of mangroves.

Directory of Open Access Journals (Sweden)

Catherine E Lovelock

Full Text Available Nutrient enrichment of the coastal zone places intense pressure on marine communities. Previous studies have shown that growth of intertidal mangrove forests is accelerated with enhanced nutrient availability. However, nutrient enrichment favours growth of shoots relative to roots, thus enhancing growth rates but increasing vulnerability to environmental stresses that adversely affect plant water relations. Two such stresses are high salinity and low humidity, both of which require greater investment in roots to meet the demands for water by the shoots. Here we present data from a global network of sites that documents enhanced mortality of mangroves with experimental nutrient enrichment at sites where high sediment salinity was coincident with low rainfall and low humidity. Thus the benefits of increased mangrove growth in response to coastal eutrophication is offset by the costs of decreased resilience due to mortality during drought, with mortality increasing with soil water salinity along climatic gradients.

Dynamic Response of Plant Chlorophyll Fluorescence to Light, Water and Nutrient Availability

Science.gov (United States)

Cendrero Mateo, M. D. P.; Moran, S. M.; Porcar-Castell, A.; Carmo-Silva, A. E.; Papuga, S. A.; Matveeva, M.; Wieneke, S.; Rascher, U.

2014-12-01

Photosynthesis is the most important exchange process of CO2 between the atmosphere and the land-surface. Spatial and temporal patterns of photosynthesis depend on dynamic plant-specific adaptation strategies to highly variable environmental conditions e.g. light, water, and nutrient availability. Chlorophyll fluorescence (ChF) has been proposed as a direct indicator of photosynthesis, and several studies have demonstrated its relationship with vegetation functioning at leaf and canopy level. In this study, two overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF?; Q2) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? The results of this study indicated that when the differences between treatments (water or nitrogen) drive the relationship between photosynthesis and ChF, ChF has a direct relationship with photosynthesis. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a simple linear function due to the complex physiological relation between photosynthesis and ChF. Our study showed that at times in the season when nitrogen was sufficient and photosynthesis was highest, ChF decreased because these two processes compete for available energy. The results from this study demonstrated that ChF is a reliable indicator of plant stress and has great potential as a tool for better understand where, when, and how CO2 is exchanged between the land and atmosphere.

Zn availability in nutrient solutions for cucumber (Cucumis sativus L) in hydroponics as affected by Fe-chelates and pH

NARCIS (Netherlands)

Voogt, W.; Sonneveld, C.

2017-01-01

In soil-less culture systems Fe is usually supplied as chelate to ensure an adequate availability of this element. As chelates have affinity for many metal ions these chelates will interact with other cation nutrients in nutrient solutions. This affects the availability of Fe and other nutrients.

Seasonal amounts of nutrients in Western cherry fruit fly (Diptera: Tephritidae) and their relation to nutrient availability on cherry plant surfaces.

Science.gov (United States)

Yee, Wee L; Chapman, Peter S

2008-10-01

Relatively little is known about the nutritional ecology of fruit flies in the genus Rhagoletis. In this study, nutrient amounts in male and female western cherry fruit fly, Rhagoletis indifferens Curran, and availability of nitrogen and sugar on surfaces of leaves, fruit, and extrafloral nectaries (EFNs) of sweet cherry trees, were determined from late May to late June 2005 and of sugar from EFNs from mid-May to late June 2007 in Washington state. Protein amounts in male and female flies did not differ over the season. Nitrogen was present on leaves, fruit, and EFNs during the sampling period, but amounts on leaves and fruit were lower in late May than the rest of the season. Sugar amounts in flies did not differ over the season. Sugar was present on leaf, fruit, and EFN surfaces all season, but amounts on all three were lower in late May than later in the season. Fructose and glucose were the predominant sugars on all plant surfaces, but sucrose was also present in nectar from EFNs. In outdoor and field cage experiments in 2004 and 2006, more flies survived when cherry branches with leaves and fruit were present than absent. Results suggest that R. indifferens maintains stable protein and sugar levels throughout the season because sufficient amounts of nutrients are found in cherry trees during this time and that increases in nutrient availability caused by ripening and damaged cherries later in the season do not result in increased amounts of nutrients in flies.

Differences in egg nutrient availability, development, and nutrient metabolism of broiler and layer embryos.

Science.gov (United States)

Nangsuay, A; Molenaar, R; Meijerhof, R; van den Anker, I; Heetkamp, M J W; Kemp, B; van den Brand, H

2015-03-01

Selection for production traits of broilers and layers leads to physiological differences, which may already be present during incubation. This study aimed to investigate the influence of strain (broiler vs layer) on egg nutrient availability, embryonic development and nutrient metabolism. A total of 480 eggs with an egg weight range of 62.0 to 64.0 g from Lohmann Brown Lite and Ross 308 breeder flocks of 41 or 42 weeks of age were selected in two batches of 120 eggs per batch per strain. For each batch, 30 eggs per strain were used to determine egg composition, including nutrient and energy content, and 90 eggs per strain were separately incubated in one of two climate respiration chambers at an eggshell temperature of 37.8°C. The results showed that broiler eggs had a higher ratio of yolk: albumen with 2.41 g more yolk and 1.48 g less albumen than layers. The yolk energy content of broiler eggs was 46.32 kJ higher than that of layer eggs, whereas total energy content of broiler eggs was 47.85 kJ higher compared to layer eggs. Yolk-free body mass at incubation day 16 and chick weight and length at hatch were higher in broilers compared to layers. Respiration quotient of broiler embryos was higher than layer embryos during incubation day 8 to incubation day 10. A 0.24 g lower residual yolk at the hatch of broiler embryos than for the layer embryos indicated that broiler embryos used more yolk and had a higher energy utilization and energy deposition in yolk-free body mass. Heat production of broiler embryos was higher than that of layer embryos from incubation day 12 to incubation day 18, but efficiency of converting egg energy used by embryos to form yolk-free body mass was similar. In conclusion, broiler and layer embryos have different embryonic development patterns, which affect energy utilization and embryonic heat production. However, the embryos are equal in efficiency of converting the energy used to yolk-free body mass. © 2015 Poultry Science

Food and nutrient availability in New Zealand: an analysis of supermarket sales data.

Science.gov (United States)

Hamilton, Sally; Mhurchu, Cliona Ni; Priest, Patricia

2007-12-01

To examine food and nutrient availability in New Zealand using supermarket sales data in conjunction with a brand-specific supermarket food composition database (SFD). The SFD was developed by selecting the top-selling supermarket food products and linking them to food composition data from a variety of sources, before merging with individualised sales data. Supermarket food and nutrient data were then compared with data from national nutrition and household budget/economic surveys. A supermarket in Wellington, New Zealand. Eight hundred and eighty-two customers (73% female; mean age 38 years) who shopped regularly at the participating supermarket store and for whom electronic sales data were available for the period February 2004-January 2005. Top-selling supermarket food products included full-fat milk, white bread, sugary soft drinks and butter. Key food sources of macronutrients were similar between the supermarket sales database and national nutrition surveys. For example, bread was the major source of energy and contributed 12-13% of energy in all three data sources. Proportional expenditure on fruit, vegetables, meat, poultry, fish, farm products and oils, and cereal products recorded in the Household Economic Survey and supermarket sales data were within 2% of each other. Electronic supermarket sales data can be used to evaluate a number of important aspects of food and nutrient availability. Many of our findings were broadly comparable with national nutrition and food expenditure survey data, and supermarket sales have the advantage of being an objective, convenient, up-to-date and cost-effective measure of household food purchases.

A dual porosity model of nutrient uptake by root hairs

KAUST Repository

Zygalakis, K. C.; Kirk, G. J. D.; Jones, D. L.; Wissuwa, M.; Roose, T.

2011-01-01

Summary: • The importance of root hairs in the uptake of sparingly soluble nutrients is understood qualitatively, but not quantitatively, and this limits efforts to breed plants tolerant of nutrient-deficient soils. • Here, we develop a mathematical model of nutrient uptake by root hairs allowing for hair geometry and the details of nutrient transport through soil, including diffusion within and between soil particles. We give illustrative results for phosphate uptake. • Compared with conventional 'single porosity' models, this 'dual porosity' model predicts greater root uptake because more nutrient is available by slow release from within soil particles. Also the effect of soil moisture is less important with the dual porosity model because the effective volume available for diffusion in the soil is larger, and the predicted effects of hair length and density are different. • Consistent with experimental observations, with the dual porosity model, increases in hair length give greater increases in uptake than increases in hair density per unit main root length. The effect of hair density is less in dry soil because the minimum concentration in solution for net influx is reached more rapidly. The effect of hair length is much less sensitive to soil moisture. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

A dual porosity model of nutrient uptake by root hairs

KAUST Repository

Zygalakis, K. C.

2011-08-09

Summary: • The importance of root hairs in the uptake of sparingly soluble nutrients is understood qualitatively, but not quantitatively, and this limits efforts to breed plants tolerant of nutrient-deficient soils. • Here, we develop a mathematical model of nutrient uptake by root hairs allowing for hair geometry and the details of nutrient transport through soil, including diffusion within and between soil particles. We give illustrative results for phosphate uptake. • Compared with conventional \\'single porosity\\' models, this \\'dual porosity\\' model predicts greater root uptake because more nutrient is available by slow release from within soil particles. Also the effect of soil moisture is less important with the dual porosity model because the effective volume available for diffusion in the soil is larger, and the predicted effects of hair length and density are different. • Consistent with experimental observations, with the dual porosity model, increases in hair length give greater increases in uptake than increases in hair density per unit main root length. The effect of hair density is less in dry soil because the minimum concentration in solution for net influx is reached more rapidly. The effect of hair length is much less sensitive to soil moisture. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Soluble organic nutrient fluxes

Science.gov (United States)

Robert G. Qualls; Bruce L. Haines; Wayne Swank

2014-01-01

Our objectives in this study were (i) compare fluxes of the dissolved organic nutrients dissolved organic carbon (DOC), DON, and dissolved organic phosphorus (DOP) in a clearcut area and an adjacent mature reference area. (ii) determine whether concentrations of dissolved organic nutrients or inorganic nutrients were greater in clearcut areas than in reference areas,...

Wildfire and forest disease interaction lead to greater loss of soil nutrients and carbon.

Science.gov (United States)

Cobb, Richard C; Meentemeyer, Ross K; Rizzo, David M

2016-09-01

Fire and forest disease have significant ecological impacts, but the interactions of these two disturbances are rarely studied. We measured soil C, N, Ca, P, and pH in forests of the Big Sur region of California impacted by the exotic pathogen Phytophthora ramorum, cause of sudden oak death, and the 2008 Basin wildfire complex. In Big Sur, overstory tree mortality following P. ramorum invasion has been extensive in redwood and mixed evergreen forests, where the pathogen kills true oaks and tanoak (Notholithocarpus densiflorus). Sampling was conducted across a full-factorial combination of disease/no disease and burned/unburned conditions in both forest types. Forest floor organic matter and associated nutrients were greater in unburned redwood compared to unburned mixed evergreen forests. Post-fire element pools were similar between forest types, but lower in burned-invaded compared to burned-uninvaded plots. We found evidence disease-generated fuels led to increased loss of forest floor C, N, Ca, and P. The same effects were associated with lower %C and higher PO4-P in the mineral soil. Fire-disease interactions were linear functions of pre-fire host mortality which was similar between the forest types. Our analysis suggests that these effects increased forest floor C loss by as much as 24.4 and 21.3 % in redwood and mixed evergreen forests, respectively, with similar maximum losses for the other forest floor elements. Accumulation of sudden oak death generated fuels has potential to increase fire-related loss of soil nutrients at the region-scale of this disease and similar patterns are likely in other forests, where fire and disease overlap.

Nutrient availability limits biological production in Arctic sea ice melt ponds

DEFF Research Database (Denmark)

Sørensen, Heidi Louise; Thamdrup, Bo; Jeppesen, Erik

2017-01-01

nutrient limitation in melt ponds. We also document that the addition of nutrients, although at relative high concentrations, can stimulate biological productivity at several trophic levels. Given the projected increase in first-year ice, increased melt pond coverage during the Arctic spring and potential......Every spring and summer melt ponds form at the surface of polar sea ice and become habitats where biological production may take place. Previous studies report a large variability in the productivity, but the causes are unknown. We investigated if nutrients limit the productivity in these first...... additional nutrient supply from, e.g. terrestrial sources imply that biological activity of melt ponds may become increasingly important for the sympagic carbon cycling in the future Arctic....

Earthworms and nutrient availability: the ecosystem engineer as (bio)chemical engineer

Science.gov (United States)

van Groenigen, Jan Willem; Ros, Mart; Vos, Hannah; De Deyn, Gerlinde; Hiemstra, Tjisse; Oenema, Oene; Koopmans, Gerwin

2017-04-01

The ability of earthworms to increase plant production has long been recognized. However, the pathways through which they do so, and the magnitude of this effect, have not been conclusively addressed. In two studies we address these issues for nitrogen (N) and phosphorus (P) availability to plants. In the first study, a meta-analysis, we concluded that earthworm presence increases crop yield on average with 26% and aboveground biomass with 24%. The positive effects of earthworms increase when more residue is returned to the soil, but disappear when soil N availability is high. This suggests that earthworms stimulate plant growth predominantly through N mineralization from soil organic matter or crop residue. In a second study, we tested the effect of earthworms on plant P uptake from inorganic sources. In a greenhouse experiment on a soil with low P availability we showed that presence of the anecic earthworm Lumbricus terrestris resulted in increased aboveground biomass (from 164 to 188 g dry matter m-2) and P uptake (from 0.21 to 0.27 g m-2). Concentrations of total dissolved P and dissolved inorganic P in water extractions of earthworm casts were 7-9 times higher than in those of bulk soil. Using advanced surface complexation modelling, we showed that these effects were primarily related to desorption of inorganic P due to competition with organic carbon for binding sites. We conclude that earthworms can alter nutrient cycling and increase N and P uptake by plants through a combination of biochemical and chemical pathways. Earthworms are most likely to stimulate N uptake in organic farming systems and tropical subsistence farming, which largely rely on nutrient mineralization. Additional benefits of earthworms might be expected in conventional farming systems with low levels of available P.

Predicting the profile of nutrients available for absorption: from nutrient requirement to animal response and environmental impact

NARCIS (Netherlands)

Dijkstra, J.; Kebreab, E.; Mills, J.A.N.; Pellikaan, W.F.; López, S.; Bannink, A.; France, J.

2007-01-01

Current feed evaluation systems for dairy cattle aim to match nutrient requirements with nutrient intake at pre-defined production levels. These systems were not developed to address, and are not suitable to predict, the responses to dietary changes in terms of production level and product

Nutrient use preferences among soil Streptomyces suggest greater resource competition in monoculture than polyculture plant communities

Science.gov (United States)

Nutrient use overlap among sympatric Streptomyces populations is correlated with pathogen inhibitory capacity, yet there is little information on either the factors that influence nutrient use overlap among coexisting populations or the diversity of nutrient use among soil Streptomyces. We examined ...

Growth of non-Saccharomyces yeasts affects nutrient availability for Saccharomyces cerevisiae during wine fermentation.

Science.gov (United States)

Medina, Karina; Boido, Eduardo; Dellacassa, Eduardo; Carrau, Francisco

2012-07-02

Yeast produces numerous secondary metabolites during fermentation that impact final wine quality. Although it is widely recognized that growth of diverse non-Saccharomyces (NS) yeast can positively affect flavor complexity during Saccharomyces cerevisiae wine fermentation, the inability to control spontaneous or co-fermentation processes by NS yeast has restricted their use in winemaking. We selected two NS yeasts from our Uruguayan native collection to study NS-S. cerevisiae interactions during wine fermentation. The selected strains of Hanseniaspora vineae and Metschnikowia pulcherrima had different yeast assimilable nitrogen consumption profiles and had different effects on S. cerevisiae fermentation and growth kinetics. Studies in which we varied inoculum size and using either simultaneous or sequential inoculation of NS yeast and S. cerevisiae suggested that competition for nutrients had a significant effect on fermentation kinetics. Sluggish fermentations were more pronounced when S. cerevisiae was inoculated 24h after the initial stage of fermentation with a NS strain compared to co-inoculation. Monitoring strain populations using differential WL nutrient agar medium and fermentation kinetics of mixed cultures allowed for a better understanding of strain interactions and nutrient addition effects. Limitation of nutrient availability for S. cerevisiae was shown to result in stuck fermentations as well as to reduce sensory desirability of the resulting wine. Addition of diammonium phosphate (DAP) and a vitamin mix to a defined medium allowed for a comparison of nutrient competition between strains. Addition of DAP and the vitamin mix was most effective in preventing stuck fermentations. Copyright © 2012 Elsevier B.V. All rights reserved.

Determination of Plant-Available Nutrients in Two Wood Ashes: the Influence of Combustion Conditions

Czech Academy of Sciences Publication Activity Database

Perná, Ivana; Ochecová, P.; Száková, J.; Hanzlíček, Tomáš; Tlustoš, P.

2016-01-01

Roč. 47, 13/14 (2016), 1664-1674 ISSN 0010-3624 R&D Projects: GA MZe QI102A207 Institutional support: RVO:67985891 Keywords : combustion condition * crystal phases * fertilizer * plant-available nutrients * wood ash Subject RIV: DM - Solid Waste and Recycling Impact factor: 0.589, year: 2016

Changes in the oligomerization potential of the division inhibitor UgtP co-ordinate Bacillus subtilis cell size with nutrient availability.

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Chien, An-Chun; Zareh, Shannon Kian Gharabiklou; Wang, Yan Mei; Levin, Petra Anne

2012-11-01

How cells co-ordinate size with growth and development is a major, unresolved question in cell biology. In previous work we identified the glucosyltransferase UgtP as a division inhibitor responsible for increasing the size of Bacillus subtilis cells under nutrient-rich conditions. In nutrient-rich medium, UgtP is distributed more or less uniformly throughout the cytoplasm and concentrated at the cell poles and/or the cytokinetic ring. Under these conditions, UgtP interacts directly with FtsZ to inhibit division and increase cell size. Conversely, under nutrient-poor conditions, UgtP is sequestered away from FtsZ in punctate foci, and division proceeds unimpeded resulting in a reduction in average cell size. Here we report that nutrient-dependent changes in UgtP's oligomerization potential serve as a molecular rheostat to precisely co-ordinate B. subtilis cell size with nutrient availability. Our data indicate UgtP interacts with itself and the essential cell division protein FtsZ in a high-affinity manner influenced in part by UDP glucose, an intracellular proxy for nutrient availability. These findings support a model in which UDP-glc-dependent changes in UgtP's oligomerization potential shift the equilibrium between UgtP•UgtP and UgtP•FtsZ, fine-tuning the amount of FtsZ available for assembly into the cytokinetic ring and with it cell size. © 2012 Blackwell Publishing Ltd.

Complete nutrient content of four species of commercially available feeder insects fed enhanced diets during growth.

Science.gov (United States)

Finke, Mark D

2015-11-01

Commercially raised feeder insects used to feed captive insectivores are a good source of many nutrients but are deficient in several key nutrients. Current methods used to supplement insects include dusting and gut-loading. Here, we report on the nutrient composition of four species of commercially raised feeder insects fed a special diet to enhance their nutrient content. Crickets, mealworms, superworms, and waxworms were analyzed for moisture, crude protein, fat, ash, acid detergent fiber, total dietary fiber, minerals, amino acids, fatty acids, vitamins, taurine, carotenoids, inositol, and cholesterol. All four species contained enhanced levels of vitamin E and omega 3 fatty acids when compared to previously published data for these species. Crickets, superworms, and mealworms contained β-carotene although using standard conversion factors only crickets and superworms would likely contain sufficient vitamin A activity for most species of insectivores. Waxworms did not contain any detectable β-carotene but did contain zeaxanthin which they likely converted from dietary β-carotene. All four species contained significant amounts of both inositol and cholesterol. Like previous reports all insects were a poor source of calcium and only superworms contained vitamin D above the limit of detection. When compared to the nutrient requirements as established by the NRC for growing rats or poultry, these species were good sources of most other nutrients although the high fat and low moisture content of both waxworms and superworms means when corrected for energy density these two species were deficient in more nutrients than crickets or mealworms. These data show the value of modifying the diet of commercially available insects as they are growing to enhance their nutrient content. They also suggest that for most insectivores properly supplemented lower fat insects such as crickets, or smaller mealworms should form the bulk of the diet. © 2015 The Authors. Zoo Biology

Central nervous control of nutrient availability and utilization.

NARCIS (Netherlands)

Steffens, A.B; Benthem, L; van der Heide, D.; Huisman, E.A.; Kanis, E.; Osse, J.W.M.; Verstegen, M.W.A.

1999-01-01

In resting animals (rats) fed ad libitum on carbohydrate-rich food, nutrient deposition in the reserves (glycogen in liver and fat in adipocytes) is in equilibrium with utilization. In this situation, metabolic needs are covered for 50% energy by glucose and 50% energy by free fatty acids (FFA). The

The effects of leaf litter nutrient pulses on Alliaria petiolata performance

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Robert W. Heckman

2015-08-01

Full Text Available Nutrient pulses can facilitate species establishment and spread in new habitats, particularly when one species more effectively uses that nutrient pulse. Biological differences in nutrient acquisition between native and exotic species may facilitate invasions into a variety of habitats including deciduous forest understories. Alliaria petiolata (Bieb. Cavara & Grande is an important invader of deciduous forest understories throughout much of North America. These understory communities contain many species which perform the majority of their growth and reproduction before canopy closure in spring. Because A. petiolata is a wintergreen biennial that can be active during autumn and winter, it may utilize nutrients released from decaying leaf litter before its competitors. To investigate this we manipulated the timing of leaf litter addition (fall or spring and experimentally simulated the nutrient pulse from decaying leaves using artificial fertilizer. To determine whether A. petiolata affected the abundance of understory competitors, we also removed A. petiolata from one treatment. A. petiolata that received early nutrients exhibited greater growth. Treatments receiving fall leaf litter or artificial nutrients had greater A. petiolata adult biomass than plots receiving spring nutrient additions (leaf litter or artificial nutrients. However, fall leaf litter addition had no effect on the richness of competitor species. Thus, wintergreen phenology may contribute to the spread of A. petiolata through deciduous forest understories, but may not explain community-level impacts of A. petiolata in deciduous forests.

Farm management, not soil microbial diversity, controls nutrient loss from smallholder tropical agriculture

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Stephen A Wood

2015-03-01

Full Text Available Tropical smallholder agriculture supports the livelihoods of over 900 million of the world’s poorest people. This form of agriculture is undergoing rapid transformation in nutrient cycling pathways as international development efforts strongly promote greater use of mineral fertilizers to increase crop yields. These changes in nutrient availability may alter the composition of microbial communities with consequences for rates of biogeochemical processes that control nutrient losses to the environment. Ecological theory suggests that altered microbial diversity will strongly influence processes performed by relatively few microbial taxa, such as denitrification and hence nitrogen losses as nitrous oxide, a powerful greenhouse gas. Whether this theory helps predict nutrient losses from agriculture depends on the relative effects of microbial community change and increased nutrient availability on ecosystem processes. We find that mineral and organic nutrient addition to smallholder farms in Kenya alters the taxonomic and functional diversity of soil microbes. However, we find that the direct effects of farm management on both denitrification and carbon mineralization are greater than indirect effects through changes in the taxonomic and functional diversity of microbial communities. Changes in functional diversity are strongly coupled to changes in specific functional genes involved in denitrification, suggesting that it is the expression, rather than abundance, of key functional genes that can serve as an indicator of ecosystem process rates. Our results thus suggest that widely used broad summary statistics of microbial diversity based on DNA may be inappropriate for linking microbial communities to ecosystem processes in certain applied settings. Our results also raise doubts about the relative control of microbial composition compared to direct effects of management on nutrient losses in applied settings such as tropical agriculture.

Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

Science.gov (United States)

Cynthia J. Tant; Amy D. Rosemond; Matthew R. First

2013-01-01

Nutrient enrichment affects bacteria and fungi associated with detritus, but little is known about how biota associated with different size fractions of organic matter respond to nutrients. Bacteria dominate on fine (1 mm) fractions, which are used by different groups of detritivores. We measured the effect of experimental...

78 FR 50088 - Notice of Availability of the Northwest Colorado Greater Sage-Grouse Draft Resource Management...

Science.gov (United States)

2013-08-16

... Availability of the Northwest Colorado Greater Sage- Grouse Draft Resource Management Plan Amendment and Draft... Land Management (BLM) has prepared a Northwest Colorado Greater Sage-Grouse Draft Resource Management.../or mailings. ADDRESSES: You may submit comments related to the Northwest Colorado Greater Sage-Grouse...

Growth of mature boreal Norway spruce was not affected by elevated [CO(2)] and/or air temperature unless nutrient availability was improved.

Science.gov (United States)

Sigurdsson, Bjarni D; Medhurst, Jane L; Wallin, Göran; Eggertsson, Olafur; Linder, Sune

2013-11-01

The growth responses of mature Norway spruce (Picea abies (L.) Karst.) trees exposed to elevated [CO(2)] (CE; 670-700 ppm) and long-term optimized nutrient availability or elevated air temperature (TE; ±3.9 °C) were studied in situ in northern Sweden in two 3 year field experiments using 12 whole-tree chambers in ca. 40-year-old forest. The first experiment (Exp. I) studied the interactions between CE and nutrient availability and the second (Exp. II) between CE and TE. It should be noted that only air temperature was elevated in Exp. II, while soil temperature was maintained close to ambient. In Exp. I, CE significantly increased the mean annual height increment, stem volume and biomass increment during the treatment period (25, 28, and 22%, respectively) when nutrients were supplied. There was, however, no significant positive CE effect found at the low natural nutrient availability. In Exp. II, which was conducted at the natural site fertility, neither CE nor TE significantly affected height or stem increment. It is concluded that the low nutrient availability (mainly nitrogen) in the boreal forests is likely to restrict their response to the continuous rise in [CO(2)] and/or TE.

The influence of savanna trees on nutrient, water and light availability and the understorey vegetation

NARCIS (Netherlands)

Ludwig, F.; Kroon, de H.; Berendse, F.; Prins, H.H.T.

2004-01-01

In an East African savanna herbaceous layer productivity and species composition were studied around Acacia tortilis trees of three different age classes, as well as around dead trees and in open grassland patches. The effects of trees on nutrient, light and water availability were measured to

Plant availability of nutrients recovered as solids from human urine tested in climate chamber on Triticum aestivum L.

Science.gov (United States)

Ganrot, Zsófia; Dave, Göran; Nilsson, Eva; Li, Bo

2007-11-01

Recovered nutrients by freezing-thawing from human urine in combination with struvite precipitation and nitrogen adsorption on zeolite and activated carbon have been tested in pot trials with wheat, Triticum aestivum L., in a climate chamber during 21 days. A simple test design using sand as substrate was chosen to give a first, general evaluation of the nutrient (P and N) availability from these sources. Dry weight, plant growth morphology, total-P and total-N were analysed. The tests show a slow-release of nutrients (P and N) from struvite and from N-adsorbents. The nitrogen in all treatments was in the deficiency range for optimum yield for wheat. Higher pH than usual for soil tests contributed to the difficulties in plant uptake, especially in the pots with only struvite (with highest MgO addition) as nutrient source.

N, P and K budgets along nutrient availability-productivity gradients in wetlands

NARCIS (Netherlands)

Olde Venterink, H.; Pieterse, N.M.; Belgers, J.D.M.; Wassen, M.J.; Ruiter, P.C. de

2002-01-01

Nutrient enrichment in Western Europe is an important cause of wetland deterioration and the concomitant loss of biodiversity. We quantified nitrogen, phosphorus, and potassium budgets along biomass gradients in wet meadows and fens (44 field sites) to evaluate the importance of various nutrient

The texture, structure and nutrient availability of artificial soil on cut slopes restored with OSSS - Influence of restoration time.

Science.gov (United States)

Huang, Zhiyu; Chen, Jiao; Ai, Xiaoyan; Li, Ruirui; Ai, Yingwei; Li, Wei

2017-09-15

Outside soil spray seeding (OSSS) is widely used to restore cut slopes in southwest of China, and artificial soil is often sprayed onto cut slopes to establish a soil layer for revegetation. The stability of artificial soil layer and its supply of water and nutrients for plants is crucial for successful restoration. To evaluate the long-term effectiveness of OSSS, the texture, structure and nutrient availability of artificial soil were studied, various soil samples were obtained from three cut slopes with different restoration time (restored with OSSS in 1996, 2003 and 2007 respectively) and one natural developed slope (NS). The properties measured including soil particle size distribution (PSD), texture, fractal dimension of PSD (D m ), the bias (C S ) and peak convex (C E ) coefficients of aggregate size distribution, structure failure rate, bulk density, moisture, pH, soil organic carbon (SOC), calcium carbonate content, Available nitrogen (N A ), Available phosphorus (P A ), and Available potassium (K A ). The results showed that different restoration time resulted in significant differences in soil PSD, D m , C S , C E , structure failure rate, bulk density, moisture, pH, N A , and K A . And these properties improved with increasing restoration age. However, there is still a huge disparity in soil texture, structure, and the availability of nutrients and moisture between the cut slopes and NS over a restoration period of up to 17 years, and this is caused by the little fine particles and the lack of slow release fertilizers and organic fertilizers in the artificial soil, resulting in poorer soil structure stability, retention and availability of moisture and nutrients on the cut slopes. Overall, the OSSS technique shows a long-term effectiveness in southwest of China, but there is still room for improvement. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phytomass production and nutrient accumulation by green manure species

Directory of Open Access Journals (Sweden)

José Carlos Soares Mangaravite

2014-10-01

Full Text Available Green manuring is recognized as a viable alternative to improve nutrient cycling in soils. The aim of this study was to evaluate the phytomass production and nutrient accumulation in shoots of the summer green manures jack bean [Canavalia ensiformis (L. DC.], dwarf pigeon pea (Cajanus cajanvar var. Flavus DC., dwarf mucuna [Mucuna deeringiana (Bort Merr] and sunn hemp (Crotalaria juncea L., under nitrogen fertilization and/or inoculation with N-fixing bacteria. A split plot design was arranged with the four Fabaceae species as main plots and nitrogen fertilization (with and without and inoculation with diazotrophic bacteria (with and without as the subplots, in a 2² factorial. The experiment was arranged as a randomized complete block design with four replications. In the conditions of this trial, the sunn hemp had the highest production of shoot phytomass (12.4 Mg ha-1 and nutrient accumulation, while the dwarf mucuna had the lowest production of shoot phytomass (3.9 Mg ha-1 and nutrient accumulation. The results showed no effect of nitrogen fertilization or inoculation with N-fixing bacteria on the production of shoot phytomass and nutrient accumulation, except for inoculation without nitrogen fertilization, resulting in greater P accumulation (p <0.05 in the sunn hemp and greater Zn and Mn accumulation in the dwarf mucuna. These findings indicate that N fertilization or inoculation with N2-fixing bacteria for Fabaceae are low efficiency practices in the edaphoclimatic conditions of this study.

Soil Nutrient Availability, Plant Nutrient Uptake, and Wild Blueberry (Vaccinium angustifolium Ait. Yield in Response to N-Viro Biosolids and Irrigation Applications

Directory of Open Access Journals (Sweden)

Aitazaz A. Farooque

2012-01-01

Full Text Available We compared the impact of surface broadcasted N-Viro biosolids and inorganic fertilizer (16.5% Ammonium sulphate, 34.5% Diammonium phosphate, 4.5% Potash, and 44.5% s and/or clay filler applications on soil properties and nutrients, leaf nutrient concentration, and the fruit yield of lowbush blueberry under irrigated and nonirrigated conditions during 2008-2009 at Debert, NS, Canada. Application rates of N-Viro biosolids were more than double of inorganic fertilizer applied at a recommended N rate of 32 kg ha−1. The experimental treatments NI: N-Viro with irrigation, FI: inorganic fertilizer with irrigation, N: N-Viro without irrigation, and F: inorganic fertilizer without irrigation (control were replicated four times under a randomized complete block design. The NI treatment had the highest OM (6.68% followed by FI (6.32%, N (6.18%, and F (4.43% treatments during the year 2008. Similar trends were observed during 2009 with the highest soil OM values (5.50% for NI treatment. Supplemental irrigation resulted in a 21% increase in the ripe fruit yield. Nonsignificant effect of fertilizer treatments on most of the nutrient concentrations in soil and plant leaves, and on ripe fruits yield reflects that the performance of N-Viro was comparable with that of the inorganic fertilizer used in this study.

Aeolian dust nutrient contributions increase with substrate age in semi-arid ecosystems

Science.gov (United States)

Coble, A. A.; Hart, S. C.; Ketterer, M. E.; Newman, G. S.

2013-12-01

Rock-derived nutrients supplied by mineral weathering become depleted over time, and without an additional nutrient source the ecosystem may eventually regress or reach a terminal steady state. Previous studies have demonstrated that aeolian dust act as parent materials of soils and important nutrients to plants in arid regions, but the relative importance of these exogenous nutrients to the function of dry ecosystems during soil development is uncertain. Here, using strontium isotopes as a tracer and a well-constrained, three million year old substrate age gradient, we show that aeolian-derived nutrients become increasingly important to plant-available soil pools and tree (Pinus edulis) growth during the latter stages of soil development in a semi-arid climate. Furthermore, the depth of nutrient uptake increased on older substrates, suggesting that trees in arid regions acquire nutrients from greater depths as ecosystem development progresses presumably in response to nutrient depletion in the more weathered surface soils. Our results contribute to the unification of biogeochemical theory by demonstrating the similarity in roles of atmospheric nutrient inputs during ecosystem development across contrasting climates.

Biochar derived from corn straw affected availability and distribution of soil nutrients and cotton yield.

Directory of Open Access Journals (Sweden)

Xiaofei Tian

Full Text Available Biochar application as a soil amendment has been proposed as a strategy to improve soil fertility and increase crop yields. However, the effects of successive biochar applications on cotton yields and nutrient distribution in soil are not well documented. A three-year field study was conducted to investigate the effects of successive biochar applications at different rates on cotton yield and on the soil nutrient distribution in the 0-100 cm soil profile. Biochar was applied at 0, 5, 10, and 20 t ha-1 (expressed as Control, BC5, BC10, and BC20, respectively for each cotton season, with identical doses of chemical fertilizers. Biochar enhanced the cotton lint yield by 8.0-15.8%, 9.3-13.9%, and 9.2-21.9% in 2013, 2014, and 2015, respectively, and high levels of biochar application achieved high cotton yields each year. Leaching of soil nitrate was reduced, while the pH values, soil organic carbon, total nitrogen (N, and available K content of the 0-20 cm soil layer were increased in 2014 and 2015. However, the changes in the soil available P content were less substantial. This study suggests that successive biochar amendments have the potential to enhance cotton productivity and soil fertility while reducing nitrate leaching.

Potassium fertigation in highbush blueberry increases availability of K and other nutrients in the root zone

Science.gov (United States)

Fertigation with nitrogen (N) increases growth and production relative to granular N applications in blueberry, but little information is available on whether there is any benefit to fertigating with other nutrients. The plants were grown on raised beds and irrigated using two lines of drip tubing p...

[Changes in bio-availability of immobilized Cu and Zn bound to phosphate in contaminated soils with different nutrient addition].

Science.gov (United States)

Xu, Ming-Gang; Zhang, Qian; Sun, Nan; Shen, Hua-Ping; Zhang, Wen-Ju

2009-07-15

Bio-availability of Cu and Zn fixed by phosphate in contaminated soils with application of nutrients were measured by pot experiment. It was simulated for the third national standardization of copper and zinc polluted soils by adding copper and zinc nitrate into red and paddy soils, respectively and together. Phosphate amendment was added to the soils to fix Cu and Zn, then added KCl and NH4Cl or K2SO4 and (NH4)2SO4 fertilizers following to plant Ryegrass, which was harvested after 40 d. Available Cu/Zn content in soils and biomass, Cu/Zn content in the shoot of Ryegrass were determined. Results showed that, compared with no nutrient application, adding KCl and NH4 Cl/K2SO4 and (NH4)2SO4 to polluted red and paddy soils increased the available Cu and Zn content in red soil significantly. The increasing order was KCl and NH4 Cl > K2SO4 and (NH4)2SO4. Especially in single Zn polluted red soil, the available Zn content increased by 133.4% in maximum. Although adding K2SO4 and (NH4)2SO4 could promote the growth of Ryegrass on red soil, and the largest increasing was up to 22.2%, it increased Cu and Zn content in the shoot of Ryegrass for 21.5%-112.6% remarkably. These nutrient effects on available Cu and Zn were not significantly in paddy soil. It was suggested that application of nitrogen and potassium fertilizers to soils could change the bioavailability of Cu/Zn. So it is necessary to take full account of the nutrient influence to the heavy metal stability which fixed by phosphate in contaminated soils when consider contaminated soils remediation by fertilization.

Lignification in beech grown at elevated CO2 concentrations: interaction with nutrient availability and leaf maturation

International Nuclear Information System (INIS)

Blaschke, L; Forstreuter, M.; Sheppard, L. J.; Leith, K.; Murray, M. B.; Polle, A.

2002-01-01

Results of a study undertaken to investigate contradictory observations reported in the literature to the effect that growth in elevated carbon dioxide affects ontogeny, are discussed. Results of this study showed that seedlings grown at elevated carbon dioxide had nitrogen concentrations of about 15 per cent lower than seedlings grown in ambient carbon dioxide. Elevated carbon dioxide caused increased growth and biomass production in trees with a medium to high nutrient supply, but had no effect on growth of trees with a low nutrient supply rate. Because elevated carbon dioxide enhanced seedling growth in the high nutrient supply treatments, the total amount of lignin produced per seedling was higher in these treatments. Overall, the results suggest that carbon dioxide availability does not directly affect lignin concentrations, but affects them indirectly through the effects on or an interaction with nitrogen supply and growth. In seedlings, elevated carbon dioxide reduced lignin concentration on a dry mass basis, indicating diminished wood quality in a carbon dioxide-enriched atmosphere. 51 refs., 2 tabs., 5 figs

Effects of wheat straw incorporation on the availability of soil nutrients and enzyme activities in semiarid areas.

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Ting Wei

Full Text Available Soil infertility is the main barrier to dryland agricultural production in China. To provide a basis for the establishment of a soil amelioration technical system for rainfed fields in the semiarid area of northwest China, we conducted a four-year (2007-2011 field experiment to determine the effects of wheat straw incorporation on the arid soil nutrient levels of cropland cultivated with winter wheat after different straw incorporation levels. Three wheat straw incorporation levels were tested (H: 9000 kg hm(-2, M: 6000 kg hm(-2, and L: 3000 kg hm(-2 and no straw incorporation was used as the control (CK. The levels of soil nutrients, soil organic carbon (SOC, soil labile organic carbon (LOC, and enzyme activities were analyzed each year after the wheat harvest. After straw incorporation for four years, the results showed that variable straw amounts had different effects on the soil fertility indices, where treatment H had the greatest effect. Compared with CK, the average soil available N, available P, available K, SOC, and LOC levels were higher in the 0-40 cm soil layers after straw incorporation treatments, i.e., 9.1-30.5%, 9.8-69.5%, 10.3-27.3%, 0.7-23.4%, and 44.4-49.4% higher, respectively. On average, the urease, phosphatase, and invertase levels in the 0-40 cm soil layers were 24.4-31.3%, 9.9-36.4%, and 42.9-65.3% higher, respectively. Higher yields coupled with higher nutrient contents were achieved with H, M and L compared with CK, where these treatments increased the crop yields by 26.75%, 21.51%, and 7.15%, respectively.

Flower-level developmental plasticity to nutrient availability in Datura stramonium: implications for the mating system.

Science.gov (United States)

Camargo, Iván Darío; Nattero, Julieta; Careaga, Sonia A; Núñez-Farfán, Juan

2017-10-17

Studies of phenotypic plasticity in plants have mainly focused on (1) the effect of environmental variation on whole-plant traits related to the number of modules rather than on (2) the phenotypic consequences of environmental variation in traits of individual modules. Since environmental and developmental factors can produce changes in traits related to the mating system, this study used the second approach to investigate whether within-individual variation in herkogamy-related traits is affected by the environment during plant development in two populations of Datura stramonium , an annual herb with a hypothesized persistent mixed mating system, and to determine which morphological traits may promote self-fertilization. Full-sib families of two Mexican populations of D. stramonium , with contrasting ecological histories, were grown under low, mid and high nutrient availability to investigate the effects of genetic, environmental and within-plant flower position on flower size, corolla, stamen and pistil lengths, and herkogamy. Populations showed differences in familial variation, plasticity and familial differences in plasticity in most floral traits analysed. In one population (Ticumán), the effect of flower position on trait variation varied among families, whereas in the other (Pedregal) the effect of flower position interacted with the nutrient environment. Flower size varied with the position of flowers, but in the opposite direction between populations in low nutrients; a systematic within-plant trend of reduction in flower size, pistil length and herkogamy with flower position increased the probability of self-fertilization in the Pedregal population. Besides genetic variation in floral traits between and within populations, environmental variation affects phenotypic floral trait values at the whole-plant level, as well as among flower positions. The interaction between flower position and nutrient environment can affect the plant's mating system, and

Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary

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D. R. Corbett

2010-10-01

Full Text Available For at least the past several decades, North Carolina's Neuse River Estuary (NRE has been subject to water quality problems relating to increased eutrophication. Research initiated in the past several years have addressed the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or winds, may also have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low.

This study focused on the potential change in bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH₄⁺ advective flux (resuspended was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH₄⁺ and PO₄³⁻ indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

Reactivity of the Bacteria-Water Interface: Linking Nutrient Availability to Bacteria-Metal Interactions

Science.gov (United States)

Fowle, D. A.; Daughney, C. J.; Riley, J. L.

2002-12-01

Identifying and quantifying the controls on metal mobilities in geologic systems is critical in order to understand processes such as global element cycling, metal transport in near-surface water-rock systems, sedimentary diagenesis, and mineral formation. Bacteria are ubiquitous in near-surface water-rock systems, and numerous laboratory and field studies have demonstrated that bacteria can facilitate the formation and dissolution of minerals, and enhance or inhibit contaminant transport. However, despite the growing evidence that bacteria play a key role in many geologic processes in low temperature systems, our understanding of the influence of the local nutrient dynamics of the system of interest on bacteria-metal interactions is limited. Here we present data demonstrating the effectiveness of coupling laboratory experiments with geochemical modeling to isolate the effect of nutrient availability on bacterially mediated proton and metal adsorption reactions. Experimental studies of metal-bacteria interactions were conducted in batch reactors as a function of pH, and solid-solute interactions after growth in a variety of defined and undefined media. Media nutrient composition (C,N,P) was quantified before and after harvesting the cells. Surface complexation models (SCM) for the adsorption reactions were developed by combining sorption data with the results of acid-base titrations, and in some cases zeta potential titrations of the bacterial surface. Our results indicate a clear change in both buffering potential and metal binding capacity of the cell walls of Bacillus subtilis as a function of initial media conditions. Combining current studies with our past studies on the effects of growth phase and others work on temperature dependence on metal adsorption we hope to develop a holistic surface complexation model for quantifying bacterial effects on metal mass transfer in many geologic systems.

Electrochemical attributes and availability of nutrients, toxic elements, and heavy metals in tropical soils Atributos eletroquímicos e disponibilidade de nutrientes, elementos tóxicos e metais pesados em solos tropicais

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Mauricio Paulo Ferreira Fontes

2006-12-01

Full Text Available Electrochemical properties of soils are very important for the understanding of the physico-chemical phenomena which affect soil fertility and the availability of nutrients for plants. This review highlights the electrochemical properties of tropical soils, the behavior and the availability of nutrients, toxic elements and heavy metals in the soil, especially for soils with predominant variable charge minerals. Availability of the elements is related to ionic exchange, solution speciation, and electrostatic and specific adsorptive soil properties. Empirical and surface complexation models are briefly described, and some results of their application in tropical soils are presented. A better understanding of the role of the double diffuse layer of charges and CEC on nutrient cation availability for highly weathered soils is required, as well as a solid comprehension of surface complexation models, in order to improve the knowledge regarding the behavior of anions in soils. More studies have to be conducted to generate results that enable the use of chemical speciation concepts and calculation of several constants used in surface complexation models, especially for highly weathered soils from the humid tropics. There has to be a continuing development and use of computer softwares that have already incorporated the concepts of chemical speciation and adsorption models in the study of nutrients, toxic elements and heavy metal availability in the soil-plant system.As propriedades eletroquímicas dos solos tropicais são muito importantes para entendimento dos fenômenos físico-químicos que afetam a fertilidade do solo e a disponibilidade dos nutrientes das plantas. Essa revisão destaca os atributos eletroquímicos de solos e o comportamento e a disponibilidade de nutrientes, elementos tóxicos e metais pesados no solo, especialmente aqueles com predominância de minerais com cargas variáveis. A disponibilidade dos elementos é relacionada com a

Root proliferation in decaying roots and old root channels: A nutrient conservation mechanism in oligotrophic mangrove forests?

Science.gov (United States)

McKee, K.L.

2001-01-01

1. In oligotrophic habitats, proliferation of roots in nutrient-rich microsites may contribute to overall nutrient conservation by plants. Peat-based soils on mangrove islands in Belize are characterized by the presence of decaying roots and numerous old root channels (0.1-3.5 cm diameter) that become filled with living and highly branched roots of Rhizophora mangle and Avicennia germinans. The objectives of this study were to quantify the proliferation of roots in these microsites and to determine what causes this response. 2. Channels formed by the refractory remains of mangrove roots accounted for only 1-2% of total soil volume, but the proportion of roots found within channels varied from 9 to 24% of total live mass. Successive generations of roots growing inside increasingly smaller root channels were also found. 3. When artificial channels constructed of PVC pipe were buried in the peat for 2 years, those filled with nutrient-rich organic matter had six times more roots than empty or sand-filled channels, indicating a response to greater nutrient availability rather than to greater space or less impedance to root growth. 4. Root proliferation inside decaying roots may improve recovery of nutrients released from decomposing tissues before they can be leached or immobilized in this intertidal environment. Greatest root proliferation in channels occurred in interior forest zones characterized by greater soil waterlogging, which suggests that this may be a strategy for nutrient capture that minimizes oxygen losses from the whole root system. 5. Improved efficiency of nutrient acquisition at the individual plant level has implications for nutrient economy at the ecosystem level and may explain, in part, how mangroves persist and grow in nutrient-poor environments.

Biochar derived from corn straw affected availability and distribution of soil nutrients and cotton yield.

Science.gov (United States)

Tian, Xiaofei; Li, Chengliang; Zhang, Min; Wan, Yongshan; Xie, Zhihua; Chen, Baocheng; Li, Wenqing

2018-01-01

Biochar application as a soil amendment has been proposed as a strategy to improve soil fertility and increase crop yields. However, the effects of successive biochar applications on cotton yields and nutrient distribution in soil are not well documented. A three-year field study was conducted to investigate the effects of successive biochar applications at different rates on cotton yield and on the soil nutrient distribution in the 0-100 cm soil profile. Biochar was applied at 0, 5, 10, and 20 t ha-1 (expressed as Control, BC5, BC10, and BC20, respectively) for each cotton season, with identical doses of chemical fertilizers. Biochar enhanced the cotton lint yield by 8.0-15.8%, 9.3-13.9%, and 9.2-21.9% in 2013, 2014, and 2015, respectively, and high levels of biochar application achieved high cotton yields each year. Leaching of soil nitrate was reduced, while the pH values, soil organic carbon, total nitrogen (N), and available K content of the 0-20 cm soil layer were increased in 2014 and 2015. However, the changes in the soil available P content were less substantial. This study suggests that successive biochar amendments have the potential to enhance cotton productivity and soil fertility while reducing nitrate leaching.

A microbial bioassay to estimate nutrient availability in organic fertilizers; field calibration:

International Nuclear Information System (INIS)

Salas, E.; Ramirez, C.

2001-01-01

A good correlation was recently shown between the increase in the microbial biomass (BM) in a mixture of soil/organic amendment and the growth of a test plant, sorghum, in the same substrate. This work reports the validation of the microbial assay as a potential guide to establish the fertilization rate for organic fertilizers such as compost under field conditions. A field trial was established with green pepper (Capsicum annum L.) and tomato (Lycopersicum esculentum L) as test plants. Treatments were soil alone or amended with 10% (W/W) of organic amendments of contrasting nutrient value, namely: chicken manure (CM), compost (C), bocashi (B), vermicompost (V) and coffe hulls (Br). A complete randomized block design with 4 replicates was used. The following variables were determined: plant dry weight (PSC) and fresh fruit weight (PFF) for green pepper, 97 days after showing; for tomato, plant dry weight (PST) was determined 32 days after showing. For the microbial biomass a complete randomized block design was also used, with 6 replicates, for the same mixtures. Microbial biomass was determined 2 days after amendment with glucose (0.8%) using the substrate- induce respiration assay. The organic amendments CM, C and B induced the highest values for BM as well as fro PSC, PFF and PST, which indicates a high nutrient availability for these organic amendments, whereas the organic amendments V and Br showed the lowest values (P [es

78 FR 65703 - Notice of Availability of the Idaho and Southwestern Montana Greater Sage-Grouse Draft Land Use...

Science.gov (United States)

2013-11-01

...] Notice of Availability of the Idaho and Southwestern Montana Greater Sage-Grouse Draft Land Use Plan... Environmental Impact Statement (EIS) for managing Greater Sage- Grouse (GRSG) in the Idaho and Southwestern... Southwestern Montana Greater Sage-Grouse Draft LUP Amendments/Draft EIS by any of the following methods: Email...

pH relationship and nutrient availability for cacao in an Entisol from the Colombian Amazon

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Gelber Rosas-Patiño

2017-09-01

Full Text Available Liming is a common practice in acid soil manage-ment; however, the information on liming in cacao soils of the Colombian Amazon region is precarious. Incubation curves were built in a highly acid Typic Udorthents cultivated with cacao (Theobroma cacao L. - Malvaceae, for which increasing doses (0 - 1 - 3 - 5 - 7 - 9 -11 Mg/ha of dolomite lime (Ca M g (CO32 and calcium carbonate (CaCO3 were used, in order to establish the type and amount of liming material (ME with better reactivity, and the one that is better favored with the acidity changes: pH, Al3+, H+, total acidity. Models to estimate the ME dose needed to manage the soil in order to obtain the desired pH (≥5.5 were generated. Sub-sequently, the soil was then limed under field conditions and pH, Al3+, Al in solution (Alsol, aluminum saturation (SAI, cation exchange capacity (CEC and N, P, K, Ca, Mg, Zn, Cu, B, Fe and Mn availability were evaluated. The results show that the greatest reaction of liming materials in these soils occurs after 60 days; applications of 7 Mg/ha allowed to raise the pH from 5.5 to 6.0 and decreases Al and Fe levels. These changes improved the CECand nutrient availability (Ca, Mg, P, Zn for cacao without affecting other nutrients such as N and K.

Nutrient dynamics across a dissolved organic carbon and burn gradient in central Siberia

Science.gov (United States)

Rodriguez-Cardona, B.; Coble, A. A.; Prokishkin, A. S.; Kolosov, R.; Spencer, R. G.; Wymore, A.; McDowell, W. H.

2016-12-01

In stream ecosystems, dissolved organic carbon (DOC) and nitrogen (N) processing are tightly linked. In temperate streams, greater DOC concentrations and higher DOC:NO3- ratios promote the greatest nitrate (NO3-) uptake. However, less is known about this relationship in other biomes including the arctic which is undergoing changes due to climate change contributing to thawing of permafrost and alterations in biogeochemical cycles in soils and streams. Headwater streams draining into the N. Tunguska River in the central Siberian plateau are affected by forest fires but little is known about the aquatic biogeochemical implications in both a thawing and burning landscape. There are clear patterns between carbon concentration and fire history where generally DOC concentration in streams decrease after fires and older burn sites have shown greater DOC concentrations and more bioavailable DOC that could promote greater heterotrophic uptake of NO3-. However, the relationship between nutrient dynamics, organic matter composition, and fire history in streams is not very clear. In order to assess the influence of organic matter composition and DOC concentration on nutrient uptake in arctic streams, we conducted a series of short-term nutrient addition experiments following the tracer addition for spiraling curve characterization (TASCC) method, consisting of NO3- and NH4++PO43- additions, across 4 streams that comprise a fire gradient that spans 3- >100 years since the last burn with DOC concentrations ranging between 12-23 mg C/L. We hypothesized that nutrient uptake would be greatest in older burn sites due to greater DOC concentrations and availability. We will specifically examine how nutrient uptake relates to DOC concentration and OM composition (analyzed via FTICR-MS) across the burn gradient. Across the four sites DOC concentration and DOC:NO3- ratios decreased from old burn sites to recently burned sites. Results presented here can elucidate on the potential impacts

Hydroponics: A Versatile System to Study Nutrient Allocation and Plant Responses to Nutrient Availability and Exposure to Toxic Elements.

Science.gov (United States)

Nguyen, Nga T; McInturf, Samuel A; Mendoza-Cózatl, David G

2016-07-13

Hydroponic systems have been utilized as one of the standard methods for plant biology research and are also used in commercial production for several crops, including lettuce and tomato. Within the plant research community, numerous hydroponic systems have been designed to study plant responses to biotic and abiotic stresses. Here we present a hydroponic protocol that can be easily implemented in laboratories interested in pursuing studies on plant mineral nutrition. This protocol describes the hydroponic system set up in detail and the preparation of plant material for successful experiments. Most of the materials described in this protocol can be found outside scientific supply companies, making the set up for hydroponic experiments less expensive and convenient. The use of a hydroponic growth system is most advantageous in situations where the nutrient media need to be well controlled and when intact roots need to be harvested for downstream applications. We also demonstrate how nutrient concentrations can be modified to induce plant responses to both essential nutrients and toxic non-essential elements.

Effect of enhanced nitrogen input on release of nutrients and nutrient availability in stands of tall fern Athyrium distentifolium

Science.gov (United States)

Tå¯Ma, Ivan; Holuib, Petr; Záhora, Jaroslav; Fiala, Karel

2010-05-01

Improved light conditions, after destruction of tree canopy, soil acidification and increased nitrogen availability, support intensive spreading of acidophilous perennial grasses and stands of tall fern (Athyrium distentifolium) on deforested sites in the Moravian-Silesian Beskydy Mts. (the Czech Republic). The aim of the study was to determine how higher inputs of nitrogen affect the release of nutrients during decomposition processes of fern litter. The experimental site was chosen on a southwest-facing slope of the Kněhyně Mt. (49o31´ N, 18o 32´E, 1170 m a.s.l.) in the Moravian-Silesin Beskydy Mts. in the Czech Republic. The area is characterized by an annual mean air temperature of 5.6 oC and annual precipitation of 1110 mm. A large fern stand was divided in four blocks (5x3 m) and on two of them higher doses of nitrogen were applied (50 kgN/ha in five doses in the course of the growing season). Similarly, mesh-bags with fresh natural litter of fern were used to determine rate of litter decomposition during one year. Samples were inserted in both nitrogen treated and untreated fern stands in autumn 2006 and 2007 collected in autumn 2007 and 2008. On the basis of litter amount estimated at the start and at the end of exposure and of actual content of minerals in original and exposed litter, the release and/or accumulation of minerals during decomposition were calculated. The availability (more or less in the case of ammonia-nitrogen) and movement of percolated nitrogen (mainly in the case of nitrate-nitrogen) was estimated in situ by the trapping of mineral N into the ion exchange resin (IER) inserted into special cover. The decomposition rate of native A. distentifolium litter was approximately the same (29-30 %) at both nitrogen availability, however the element release from decomposed litter was higher for N, P and Ca in both years and for K and Mg in the first year as well. However, decomposition rate of cellulose was two times greater in fern stands

Effects of Environmental Factors and Nutrient Availability on the Biochemical Composition of Algae for Biofuels Production: A Review

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Ganti S. Murthy

2013-09-01

Full Text Available Due to significant lipid and carbohydrate production as well as other useful properties such as high production of useful biomolecular substrates (e.g., lipids and the ability to grow using non-potable water sources, algae are being explored as a potential high-yield feedstock for biofuels production. In both natural and engineered systems, algae can be exposed to a variety of environmental conditions that affect growth rate and cellular composition. With respect to the latter, the amount of carbon fixed in lipids and carbohydrates (e.g., starch is highly influenced by environmental factors and nutrient availability. Understanding synergistic interactions between multiple environmental variables and nutritional factors is required to develop sustainable high productivity bioalgae systems, which are essential for commercial biofuel production. This article reviews the effects of environmental factors (i.e., temperature, light and pH and nutrient availability (e.g., carbon, nitrogen, phosphorus, potassium, and trace metals as well as cross-interactions on the biochemical composition of algae with a special focus on carbon fixation and partitioning of carbon from a biofuels perspective.

Agroforestry suitability analysis based upon nutrient availability mapping: a GIS based suitability mapping

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Firoz Ahmad

2017-05-01

Full Text Available Agroforestry has drawn the attention of researchers due to its capacity to reduce the poverty and land degradation, improve food security and mitigate the climate change. However, the progress in promoting agroforestry is held back due to the lack of reliable data sets and appropriate tools to accurately map and to have an adequate decision making system for agroforestry modules. Agroforestry suitability being one special form of land suitability is very pertinent to study in the current times when there is tremendous pressure on the land as it is a limited commodity. The study aims for applying the geo-spatial tools towards visualizing various soil and environmental data to reveal the trends and interrelationships and to achieve a nutrient availability and agroforestry suitability map. Using weight matrix and ranks, individual maps were developed in ArcGIS 10.1 platform to generate nutrient availability map, which was later used to develop agroforestry suitability map. Watersheds were delineated using DEM in some part of the study area and were evaluated for prioritizing it and agroforestry suitability of the watersheds were also done as per the schematic flowchart. Agroforestry suitability regions were delineated based upon the weight and ranks by integrated mapping. The total open area was identified 42.4% out of which 21.6% area was found to have high suitability towards agroforestry. Within the watersheds, 22 village points were generated for creating buffers, which were further evaluated showing its proximity to high suitable agroforestry sites thus generating tremendous opportunity to the villagers to carry out agroforestry projects locally. This research shows the capability of remote sensing in studying agroforestry practices and in estimating the prominent factors for its optimal productivity. The ongoing agroforestry projects can be potentially diverted in the areas of high suitability as an extension. The use of ancillary data in GIS

Nutrient content of biomass components of Hamlin sweet orange trees

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Mattos Jr. Dirceu

2003-01-01

Full Text Available The knowledge of the nutrient distribution in trees is important to establish sound nutrient management programs for citrus production. Six-year-old Hamlin orange trees [Citrus sinensis (L. Osb.] on Swingle citrumelo [Poncirus trifoliata (L. Raf. x Citrus paradisi Macfad.] rootstock, grown on a sandy Entisol in Florida were harvested to investigate the macro and micronutrient distributions of biomass components. The biomass of aboveground components of the tree represented the largest proportion of the total. The distribution of the total tree dry weight was: fruit = 30.3%, leaf = 9.7%, twig = 26.1%, trunk = 6.3%, and root = 27.8%. Nutrient concentrations of recent mature leaves were in the adequate to optimal range as suggested by interpretation of leaf analysis in Florida. Concentrations of Ca in older leaves and woody tissues were much greater than those in the other parts of the tree. Concentrations of micronutrients were markedly greater in fibrous root as compared to woody roots. Calcium made up the greatest amount of nutrient in the citrus tree (273.8 g per tree, followed by N and K (234.7 and 181.5 g per tree, respectively. Other macronutrients comprised about 11% of the total nutrient content of trees. The contents of various nutrients in fruits were: N = 1.20, K = 1.54, P = 0.18, Ca = 0.57, Mg = 0.12, S = 0.09, B = 1.63 x 10-3, Cu = 0.39 x 10-3, Fe = 2.1 x 10-3, Mn = 0.38 10-3, and Zn = 0.40 10-3 (kg ton-1. Total contents of N, K, and P in the orchard corresponded to 66.5, 52.0, and 8.3 kg ha-1, respectively, which were equivalent to the amounts applied annually by fertilization.

Biochar derived from corn straw affected availability and distribution of soil nutrients and cotton yield

Science.gov (United States)

Tian, Xiaofei; Zhang, Min; Wan, Yongshan; Xie, Zhihua; Chen, Baocheng; Li, Wenqing

2018-01-01

Biochar application as a soil amendment has been proposed as a strategy to improve soil fertility and increase crop yields. However, the effects of successive biochar applications on cotton yields and nutrient distribution in soil are not well documented. A three-year field study was conducted to investigate the effects of successive biochar applications at different rates on cotton yield and on the soil nutrient distribution in the 0–100 cm soil profile. Biochar was applied at 0, 5, 10, and 20 t ha-1 (expressed as Control, BC5, BC10, and BC20, respectively) for each cotton season, with identical doses of chemical fertilizers. Biochar enhanced the cotton lint yield by 8.0–15.8%, 9.3–13.9%, and 9.2–21.9% in 2013, 2014, and 2015, respectively, and high levels of biochar application achieved high cotton yields each year. Leaching of soil nitrate was reduced, while the pH values, soil organic carbon, total nitrogen (N), and available K content of the 0–20 cm soil layer were increased in 2014 and 2015. However, the changes in the soil available P content were less substantial. This study suggests that successive biochar amendments have the potential to enhance cotton productivity and soil fertility while reducing nitrate leaching. PMID:29324750

The influence of red wood ants .i.Formica polyctena./i. on nutrient availability ant growth of spruce tree

Czech Academy of Sciences Publication Activity Database

Frouz, Jan; Rybníček, M.; Cudlín, Pavel

2007-01-01

Roč. 9, - (2007) ISSN 1607-7962. [European Geosciences Union General Assembly 2007. 15.04.2007-20.04.2007, Vienna] Institutional research plan: CEZ:AV0Z60660521; CEZ:AV0Z60870520 Keywords : Formica polyctena * nutrient availability * growth of spruce tree Subject RIV: EH - Ecology, Behaviour

Nutrient requirements and low-cost balanced diets, based on seasonally available local feedstuffs, for local pigs on smallholder farms in Western Kenya.

Science.gov (United States)

Carter, Natalie Ann; Dewey, Catherine Elizabeth; Thomas, Lian Francesca; Lukuyu, Ben; Grace, Delia; de Lange, Cornelis

2016-02-01

Growth performance of pigs on smallholder farms in the tropics is low. Lack of feedstuffs, seasonal feed shortages, and feeding nutritionally unbalanced diets contribute to slow growth. Low-cost balanced diets are needed to improve pig performance. In this study, we estimated the nutrient requirements of local pigs on smallholder farms in Kenya and developed balanced low-cost diets using seasonally available local feedstuffs. Diets were formulated to provide pigs with 80 % of the nutrient density in corn and soybean meal-based (reference) diets to minimize the cost per unit of energy and other nutrients. Estimated requirements for starting and growing pigs (8 to 35 kg body weight) were as follows: digestible energy (DE) 2960 kcal/kg of dry matter (DM), standardized ileal digestibility (SID) lysine 5.8 g/kg of DM, calcium 2.8 g/kg of DM, standardized total tract digestible (STTD) phosphorous 1.4 g/kg of DM, and crude protein 85 g/kg of DM. Nutrient requirements of local pigs on smallholder farms in Kenya were lower than those of exotic breed pigs raised in commercial settings. Seasonally available local feedstuffs were used to develop low-cost balanced diets. Twenty-two diets are presented based on season, cost, and feedstuff availability. This study has broad applicability as a case study of an approach that could be applied in other tropical regions in which smallholder pig keeping is practiced and where local feedstuffs for pigs are available seasonally.

Nutrient synchrony in preruminant calves

NARCIS (Netherlands)

Borne, van den J.J.G.C.

2006-01-01

In animal nutrition, the nutrient composition of the daily feed supply is composed to match the nutrient requirements for the desired performance. The time of nutrient availability within a day is usually considered not to affect the fate of nutrients. The aim of this thesis was to evaluate effects

Invasive clonal plant species have a greater root-foraging plasticity than non-invasive ones.

Science.gov (United States)

Keser, Lidewij H; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

2014-03-01

Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

Illuminating pathways of forest nutrient provision: relative release from soil mineral and organic pools

Science.gov (United States)

Hauser, E.; Billings, S. A.

2017-12-01

with much lower CIA values. Thus, provision of plant-available nutrients from OM decay appears greater at more weathered sites, and dominant nutrient sources accessed by deep roots (OM- vs. rock-derived) may vary predictably with soil weathering stage. On-going incubations will permit us to assess these relationships for multiple geogenic nutrients.

Foods, Fortificants, and Supplements: Where Do Americans Get Their Nutrients?123

Science.gov (United States)

Fulgoni, Victor L.; Keast, Debra R.; Bailey, Regan L.; Dwyer, Johanna

2011-01-01

Limited data are available on the source of usual nutrient intakes in the United States. This analysis aimed to assess contributions of micronutrients to usual intakes derived from all sources (naturally occurring, fortified and enriched, and dietary supplements) and to compare usual intakes to the Dietary Reference Intake for U.S. residents aged ≥2 y according to NHANES 2003–2006 (n = 16,110). We used the National Cancer Institute method to assess usual intakes of 19 micronutrients by source. Only a small percentage of the population had total usual intakes (from dietary intakes and supplements) below the estimated average requirement (EAR) for the following: vitamin B-6 (8%), folate (8%), zinc (8%), thiamin, riboflavin, niacin, vitamin B-12, phosphorus, iron, copper, and selenium (supplements further reduced the percentage of the population consuming less than the EAR for all nutrients. The percentage of the population with total intakes greater than the tolerable upper intake level (UL) was very low for most nutrients, whereas 10.3 and 8.4% of the population had intakes greater than the UL for niacin and zinc, respectively. Without enrichment and/or fortification and supplementation, many Americans did not achieve the recommended micronutrient intake levels set forth in the Dietary Reference Intake. PMID:21865568

Nutrient Partitioning and Stoichiometry in Unburnt Sugarcane Ratoon at Varying Yield Levels

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José Marcos Leite

2016-04-01

Full Text Available Unraveling nutrient imbalances in contemporary agriculture is a research priority to improve whenever possible yield and nutrient use efficiency in sugarcane (Saccharum spp. systems while minimizing the costs of cultivation (e.g., use of fertilizers and environmental concerns. The main goal of this study was therefore to investigate biomass and nutrient [nitrogen (N, phosphorus (P, and potassium (K] content, partitioning, stoichiometry and internal efficiencies in sugarcane ratoon at varying yield levels. Three sites were established on highly weathered tropical soils located in the Southeast region of Brazil. At all sites, seasonal biomass and nutrient uptake patterns were synthesized from four sampling times taken throughout the sugarcane ratoon season. At all sites, in-season nutrient partitioning (in diverse plant components, internal efficiencies (yield to nutrient content ratio and nutrient ratios (N:P and N:K were determined at harvesting. Sugarcane exhibited three distinct phases of plant growth, as follows: lag, exponential-linear, and stationary. Across sites, nutrient requirement per unit of yield was 1.4 kg N, 0.24 kg P, and 2.7 kg K per Mg of stalk produced, but nutrient removal varied with soil nutrient status (based on soil plus fertilizer nutrient supply and crop demand (potential yield. Dry leaves had lower nutrient content (N, P, and K and broader N:P and N:K ratios when compared with tops and stalks plant fractions. Greater sugarcane yield and narrowed N:P ratio (6:1 were verified for tops of sugarcane when increasing both N and P content. High-yielding sugarcane systems were related to higher nutrient content and more balanced N:P (6:1 and N:K (0.5:1 ratios.

Bacterial invasion potential in water is determined by nutrient availability and the indigenous community.

Science.gov (United States)

Van Nevel, Sam; De Roy, Karen; Boon, Nico

2013-09-01

In drinking water (DW) and the distribution systems, bacterial growth and biofilm formation have to be controlled both for limiting taste or odour development and preventing clogging or biocorrosion problems. After a contamination with undesired bacteria, factors like nutrient availability and temperature will influence the survival of these invaders. Understanding the conditions enabling invaders to proliferate is essential for a holistic approach towards microbial risk assessment in DW. Pseudomonas putida was used as a model invader because this easy-growing bacterium can use a wide range of substrates. Invasion experiments in oligo- to eutrophic waters showed the requirement of both a carbon and phosphate source for survival of P. putida in DW. Addition of C, N and P enabled P. putida to grow in DW from 5.80 × 10(4) to 1.84 × 10(8) cells mL(-1) and survive for at least 12 days. However, in surface water with similar nutrient concentrations, P. putida did not survive, indicating the concomitant importance of the present indigenous microbial community of the specific water sample. Either extensive carbon or phosphate limitation can be used in water treatment design in order to obtain a DW which is not susceptible for unwanted bacterial growth. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Fungi benefit from two decades of increased nutrient availability in tundra heath soil

DEFF Research Database (Denmark)

Rinnan, Riikka; Michelsen, Anders; Bååth, Erland

2013-01-01

is a predicted long-term consequence of climatic warming and mimicked by fertilization, both increase soil microbial biomass. However, while fertilization increased the relative abundance of fungi, warming caused only a minimal shift in the microbial community composition based on the phospholipid fatty acid......If microbial degradation of carbon substrates in arctic soil is stimulated by climatic warming, this would be a significant positive feedback on global change. With data from a climate change experiment in Northern Sweden we show that warming and enhanced soil nutrient availability, which...... (PLFA) and neutral lipid fatty acid (NLFA) profiles. The function of the microbial community was also differently affected, as indicated by stable isotope probing of PLFA and NLFA. We demonstrate that two decades of fertilization have favored fungi relative to bacteria, and increased the turnover...

Strong hydrological control on nutrient cycling of subtropical rainforests

Science.gov (United States)

Lin, T. C.; Chang, C. T.; Huang, J. C.; Wang, L.; Lin, N. H.

2016-12-01

Forest nutrient cycling is strongly controlled by both biological and hydrological factors. However, based on a close examination of earlier reports, we highlight the role of hydrological control on nutrient cycling at a global scale and is more important at humid tropical and subtropical forests. we analyzed the nutrient budget of precipitation input and stream water output from 1994 to 2013 in a subtropical forest in Taiwan and conducted a data synthesis using results from 32 forests across the globe. The results revealed that monthly input and output of ions were positively correlated with water quantity, indicating hydrological control on nutrient cycling. Hydrological control is also evident from the greater ions export via stream water during the warm and wet growing season. The synthesis also illustrates that strong hydrological control leads to lower nitrogen retention and greater net loss of base cations in humid regions, particularly in the humid tropical and subtropical forests. Our result is of great significance in an era of global climate change because climate change could directly affect ecosystem nutrient cycling particularly in the tropics through changes in patterns of precipitation regime.

The fractal geometry of nutrient exchange surfaces does not provide an explanation for 3/4-power metabolic scaling

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Painter Page R

2005-08-01

Full Text Available Abstract Background A prominent theoretical explanation for 3/4-power allometric scaling of metabolism proposes that the nutrient exchange surface of capillaries has properties of a space-filling fractal. The theory assumes that nutrient exchange surface area has a fractal dimension equal to or greater than 2 and less than or equal to 3 and that the volume filled by the exchange surface area has a fractal dimension equal to or greater than 3 and less than or equal to 4. Results It is shown that contradicting predictions can be derived from the assumptions of the model. When errors in the model are corrected, it is shown to predict that metabolic rate is proportional to body mass (proportional scaling. Conclusion The presence of space-filling fractal nutrient exchange surfaces does not provide a satisfactory explanation for 3/4-power metabolic rate scaling.

In the other 90%: phytoplankton responses to enhanced nutrient availability in the Great Barrier Reef Lagoon

International Nuclear Information System (INIS)

Furnas, Miles; Mitchell, Alan; Skuza, Michele; Brodie, Jon

2005-01-01

Our view of how water quality effects ecosystems of the Great Barrier Reef (GBR) is largely framed by observed or expected responses of large benthic organisms (corals, algae, seagrasses) to enhanced levels of dissolved nutrients, sediments and other pollutants in reef waters. In the case of nutrients, however, benthic organisms and communities are largely responding to materials which have cycled through and been transformed by pelagic communities dominated by micro-algae (phytoplankton), protozoa, flagellates and bacteria. Because GBR waters are characterised by high ambient light intensities and water temperatures, inputs of nutrients from both internal and external sources are rapidly taken up and converted to organic matter in inter-reefal waters. Phytoplankton growth, pelagic grazing and remineralisation rates are very rapid. Dominant phytoplankton species in GBR waters have in situ growth rates which range from ∼1 to several doublings per day. To a first approximation, phytoplankton communities and their constituent nutrient content turn over on a daily basis. Relative abundances of dissolved nutrient species strongly indicate N limitation of new biomass formation. Direct ( 15 N) and indirect ( 14 C) estimates of N demand by phytoplankton indicate dissolved inorganic N pools have turnover times on the order of hours to days. Turnover times for inorganic phosphorus in the water column range from hours to weeks. Because of the rapid assimilation of nutrients by plankton communities, biological responses in benthic communities to changed water quality are more likely driven (at several ecological levels) by organic matter derived from pelagic primary production than by dissolved nutrient stocks alone

Comparative analysis of phytochemicals and nutrient availability in two contrasting cultivars of sweet potato (Ipomoea batatas L.).

Science.gov (United States)

Shekhar, Shubhendu; Mishra, Divya; Buragohain, Alak Kumar; Chakraborty, Subhra; Chakraborty, Niranjan

2015-04-15

Sweet potato ranks as the world's seventh most important food crop, and has major contribution to energy and phytochemical source of nutrition. To unravel the molecular basis for differential nutrient availability, and to exploit the natural genetic variation(s) of sweet potato, a series of physiochemical and proteomics experiment was conducted using two contrasting cultivars, an orange-fleshed sweet potato (OFSP) and a white-fleshed sweet potato (WFSP). Phytochemical screening revealed high percentage of carbohydrate, reducing sugar and phenolics in WFSP, whereas OFSP showed increased levels of total protein, flavonoids, anthocyanins, and carotenoids. The rate of starch and cellulose degradation was found to be less in OFSP during storage, indicating tight regulation of gene(s) responsible for starch-degradation. Comparative proteomics displayed a cultivar-dependent expression of proteins along with evolutionarily conserved proteins. These results suggest that cultivar-specific expression of proteins and/or their interacting partners might play a crucial role for nutrient acquisition in sweet potato. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fisheries management under nutrient influence

DEFF Research Database (Denmark)

Hammarlund, Cecilia; Nielsen, Max; Waldo, Staffan

2018-01-01

A fisheries management model that identifies the economic optimal management of fisheries under the influence of nutrients is presented. The model starts from the idea that growth in fish biomass increases with increasing availability of nutrients owing to higher food availability up to a peak...

Particle water and pH in the eastern Mediterranean: source variability and implications for nutrient availability

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A. Bougiatioti

2016-04-01

Full Text Available Particle water (liquid water content, LWC and aerosol pH are important parameters of the aerosol phase, affecting heterogeneous chemistry and bioavailability of nutrients that profoundly impact cloud formation, atmospheric composition, and atmospheric fluxes of nutrients to ecosystems. Few measurements of in situ LWC and pH, however, exist in the published literature. Using concurrent measurements of aerosol chemical composition, cloud condensation nuclei activity, and tandem light scattering coefficients, the particle water mass concentrations associated with the aerosol inorganic (Winorg and organic (Worg components are determined for measurements conducted at the Finokalia atmospheric observation station in the eastern Mediterranean between June and November 2012. These data are interpreted using the ISORROPIA-II thermodynamic model to predict the pH of aerosols originating from the various sources that influence air quality in the region. On average, closure between predicted aerosol water and that determined by comparison of ambient with dry light scattering coefficients was achieved to within 8 % (slope  =  0.92, R2  =  0.8, n  =  5201 points. Based on the scattering measurements, a parameterization is also derived, capable of reproducing the hygroscopic growth factor (f(RH within 15 % of the measured values. The highest aerosol water concentrations are observed during nighttime, when relative humidity is highest and the collapse of the boundary layer increases the aerosol concentration. A significant diurnal variability is found for Worg with morning and afternoon average mass concentrations being 10–15 times lower than nighttime concentrations, thus rendering Winorg the main form of particle water during daytime. The average value of total aerosol water was 2.19 ± 1.75 µg m−3, contributing on average up to 33 % of the total submicron mass concentration. Average aerosol water associated with

Impact of Temperature and Nutrients on Carbon: Nutrient Tissue Stoichiometry of Submerged Aquatic Plants: An Experiment and Meta-Analysis

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Mandy Velthuis

2017-05-01

Full Text Available Human activity is currently changing our environment rapidly, with predicted temperature increases of 1–5°C over the coming century and increased nitrogen and phosphorus inputs in aquatic ecosystems. In the shallow parts of these ecosystems, submerged aquatic plants enhance water clarity by resource competition with phytoplankton, provide habitat, and serve as a food source for other organisms. The carbon:nutrient stoichiometry of submerged aquatic plants can be affected by changes in both temperature and nutrient availability. We hypothesized that elevated temperature leads to higher carbon:nutrient ratios through enhanced nutrient-use efficiency, while nutrient addition leads to lower carbon:nutrient ratios by the luxurious uptake of nutrients. We addressed these hypotheses with an experimental and a meta-analytical approach. We performed a full-factorial microcosm experiment with the freshwater plant Elodea nuttallii grown at 10, 15, 20, and 25°C on sediment consisting of pond soil/sand mixtures with 100, 50, 25, and 12.5% pond soil. To address the effect of climatic warming and nutrient addition on the carbon:nutrient stoichiometry of submerged freshwater and marine plants we performed a meta-analysis on experimental studies that elevated temperature and/or added nutrients (nitrogen and phosphorus. In the microcosm experiment, C:N ratios of Elodea nuttallii decreased with increasing temperature, and this effect was most pronounced at intermediate nutrient availability. Furthermore, higher nutrient availability led to decreased aboveground C:P ratios. In the meta-analysis, nutrient addition led to a 25, 22, and 16% reduction in aboveground C:N and C:P ratios and belowground C:N ratios, accompanied with increased N content. No consistent effect of elevated temperature on plant stoichiometry could be observed, as very few studies were found on this topic and contrasting results were reported. We conclude that while nutrient addition

A review on beneficial effects of rhizosphere bacteria on soil nutrient availability and plant nutrient uptake.

OpenAIRE

Osorio Vega, Nelson Walter

2011-01-01

Este artículo se constituye en una revisión de los beneficios de bacterias rizosféricas sobre la nutrición vegetal. La interacción entre planta y bacterias solubilizadoras de fosfato es explicada en mayor detalle y usada como modelo para ilustrar el rol que algunas bacterias de la rizosfera juegan en la disponibilidad de nutrientes en el suelo. Las condiciones ambientales de la rizosfera también se discuten con detalle. Los beneficios de estas bacterias han sido obtenidos, y mejorados, en pre...

School and district wellness councils and availability of low-nutrient, energy-dense vending fare in Minnesota middle and high schools.

Science.gov (United States)

Kubik, Martha Y; Lytle, Leslie A; Farbakhsh, Kian

2011-01-01

The Child Nutrition and WIC Reauthorization Act of 2004 required school districts participating in the federal school meals program to establish by the start of the 2006-2007 school year policies that included nutrition guidelines for all foods sold on school campus during the school day and policy development involving key stakeholders. For many schools, policy development was done by wellness councils. This study examined the association between having a wellness council and availability of low-nutrient, energy-dense foods/beverages in school vending machines following enactment of the federal legislation. In 2006-2007, Minnesota middle (n=35) and high (n=54) school principals reported whether their school and district had a wellness council. Trained research staff observed foods/beverages in vending machines accessible to students. Low-nutrient, energy-dense foods/beverages (snacks >3 g fat or >200 calories/serving, and soda, fruit/sport drinks and reduced-fat/whole milk) were grouped into seven categories (eg, high-fat baked goods) and a food score was calculated. Higher scores indicated more low-nutrient, energy-dense vending fare. Multivariate linear regression, adjusted for school characteristics, was used to examine associations between scores and a three-category council variable (district-only; district and school; no council). Among schools, 53% had district-only councils, 38% district and school councils, and 9% had no council. Schools with both a district and school council had a significantly lower mean food score than schools without councils (P=0.03). The potential of wellness councils to impact availability of low-nutrient, energy-dense vending fare is promising. There may be an added benefit to having both a school and district council. Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

Effects of mountain tea plantations on nutrient cycling at upstream watersheds

Science.gov (United States)

Lin, T.-C.; Shaner, P.-J. L.; Wang, L.-J.; Shih, Y.-T.; Wang, C.-P.; Huang, G.-H.; Huang, J.-C.

2015-11-01

The expansion of agriculture to rugged mountains can exacerbate negative impacts of agricultural activities on ecosystem function. In this study, we monitored streamwater and rainfall chemistry of mountain watersheds at the Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found that the greater the proportion of tea plantation cover, the higher the concentrations of fertilizer-associated ions (NO3-, K+) in streamwater of the four mountain watersheds examined; on the other hand, the concentrations of the ions that are rich in soils (SO42-, Ca2+, Mg2+) did not increase with the proportion of tea plantation cover, suggesting that agriculture enriched fertilizer-associated nutrients in streamwater. Of the two watersheds for which rainfall chemistry was available, the one with higher proportion of tea plantation cover had higher concentrations of ions in rainfall and retained less nitrogen in proportion to input compared to the more pristine watershed, suggesting that agriculture can influence atmospheric deposition of nutrients and a system's ability to retain nutrients. As expected, we found that a forested watershed downstream of agricultural activities can dilute the concentrations of NO3- in streamwater by more than 70 %, indicating that such a landscape configuration helps mitigate nutrient enrichment in aquatic systems even for watersheds with steep topography. We estimated that tea plantation at our study site contributed approximately 450 kg ha-1 yr-1 of NO3-N via streamwater, an order of magnitude greater than previously reported for agricultural lands around the globe, which can only be matched by areas under intense fertilizer use. Furthermore, we constructed watershed N fluxes to show that excessive leaching of N, and additional loss to the atmosphere via volatilization and denitrification can occur under intense fertilizer use. In summary, this study demonstrated the pervasive impacts of

SPATIAL UNCERTAINTY OF NUTRIENT LOSS BY EROSION IN SUGARCANE HARVESTING SCENARIOS

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Patrícia Gabarra Mendonça

2015-08-01

Full Text Available The assessment of spatial uncertainty in the prediction of nutrient losses by erosion associated with landscape models is an important tool for soil conservation planning. The purpose of this study was to evaluate the spatial and local uncertainty in predicting depletion rates of soil nutrients (P, K, Ca, and Mg by soil erosion from green and burnt sugarcane harvesting scenarios, using sequential Gaussian simulation (SGS. A regular grid with equidistant intervals of 50 m (626 points was established in the 200-ha study area, in Tabapuã, São Paulo, Brazil. The rate of soil depletion (SD was calculated from the relation between the nutrient concentration in the sediments and the chemical properties in the original soil for all grid points. The data were subjected to descriptive statistical and geostatistical analysis. The mean SD rate for all nutrients was higher in the slash-and-burn than the green cane harvest scenario (Student’s t-test, pMg>K>P. The SD rate was highest in areas with greater slope. Lower uncertainties were associated to the areas with higher SD and steeper slopes. Spatial uncertainties were highest for areas of transition between concave and convex landforms.

Zooplankton taxonomic and size diversity in Mediterranean coastal lagoons (NE Iberian Peninsula): Influence of hydrology, nutrient composition, food resource availability and predation

Science.gov (United States)

Badosa, Anna; Boix, Dani; Brucet, Sandra; López-Flores, Rocío; Gascón, Stéphanie; Quintana, Xavier D.

2007-01-01

The influence of hydrology, nutrient composition, food resource availability and predation on zooplankton taxonomic and size diversity was analyzed in several shallow lagoons of a Mediterranean salt marsh (Baix Ter Wetlands, NE Iberian Peninsula). Taxonomic diversity correlated better with variables related to the trophic state, such as nutrient concentrations, whereas size diversity was more sensitive to fish predation. However, the fish predation influence on the size diversity was only significant when fishes reached high densities. Under low fish densities no predation effects were observed and the food resource availability (FR a) appeared to be more important in structuring the zooplankton community. Nevertheless, the two diversity indexes showed opposite responses to this factor. With increasing FR a the taxonomic diversity increased and the size diversity decreased. Neither taxonomic nor size diversity of the zooplankton community correlated with other physical or biotic factors such as hydrological variability or macroinvertebrate predation. The relationships found suggest that the size diversity is mainly related to biotic interactions, such as fish predation or inter/intraspecific competition, while the taxonomic diversity appears to be more sensitive to abiotic factors such as the nutrient composition.

Algal remediation of CO₂ and nutrient discharges: A review.

Science.gov (United States)

Judd, Simon; van den Broeke, Leo J P; Shurair, Mohamed; Kuti, Yussuf; Znad, Hussein

2015-12-15

The recent literature pertaining to the application of algal photobioreactors (PBRs) to both carbon dioxide mitigation and nutrient abatement is reviewed and the reported data analysed. The review appraises the influence of key system parameters on performance with reference to (a) the absorption and biological fixation of CO2 from gaseous effluent streams, and (b) the removal of nutrients from wastewaters. Key parameters appraised individually with reference to CO2 removal comprise algal speciation, light intensity, mass transfer, gas and hydraulic residence time, pollutant (CO2 and nutrient) loading, biochemical and chemical stoichiometry (including pH), and temperature. Nutrient removal has been assessed with reference to hydraulic residence time and reactor configuration, along with C:nutrient ratios and other factors affecting carbon fixation, and outcomes compared with those reported for classical biological nutrient removal (BNR). Outcomes of the review indicate there has been a disproportionate increase in algal PBR research outputs over the past 5-8 years, with a significant number of studies based on small, bench-scale systems. The quantitative impacts of light intensity and loading on CO2 uptake are highly dependent on the algal species, and also affected by solution chemical conditions such as temperature and pH. Calculations based on available data for biomass growth rates indicate that a reactor CO2 residence time of around 4 h is required for significant CO2 removal. Nutrient removal data indicate residence times of 2-5 days are required for significant nutrient removal, compared with PBR configuration (the high rate algal pond, HRAP) means that its footprint is at least two orders of magnitude greater than a classical BNR plant. It is concluded that the combined carbon capture/nutrient removal process relies on optimisation of a number of process parameters acting synergistically, principally microalgal strain, C:N:P load and balance, CO2 and liquid

Coupling nutrient uptake and energy flow in headwater streams

Energy Technology Data Exchange (ETDEWEB)

Mulholland, Patrick J [ORNL; Fellows, Christine [Griffith University, Nathan, Queensland, Australia; Valett, H. Maurice [Virginia Polytechnic Institute and State University (Virginia Tech); Dahm, Cliff [University of New Mexico, Albuquerque; Thomas, Steve [University of Nebraska

2006-08-01

Nutrient cycling and energy flow in ecosystems are tightly linked through the metabolic processes of organisms. Greater uptake of inorganic nutrients is expected to be associated with higher rates of metabolism [gross primary production (GPP) and respiration (R)], due to assimilatory demand of both autotrophs and heterotrophs. However, relationships between uptake and metabolism should vary with the relative contribution of autochthonous and allochthonous sources of organic matter. To investigate the relationship between metabolism and nutrient uptake, we used whole-stream and benthic chamber methods to measure rates of nitrate-nitrogen (NO{sub 3}-N) uptake and metabolism in four headwater streams chosen to span a range of light availability and therefore differing rates of GPP and contributions of autochthonous carbon. We coupled whole-stream metabolism with measures of NO{sub 3}-N uptake conducted repeatedly over the same stream reach during both day and night, as well as incubating benthic sediments under both light and dark conditions. NO{sub 3}-N uptake was generally greater in daylight compared to dark conditions, and although day-night differences in whole-stream uptake were not significant, light-dark differences in benthic chambers were significant at three of the four sites. Estimates of N demand indicated that assimilation by photoautotrophs could account for the majority of NO{sub 3}-N uptake at the two sites with relatively open canopies. Contrary to expectations, photoautotrophs contributed substantially to NO{sub 3}-N uptake even at the two closed-canopy sites, which had low values of GPP/R and relied heavily on allochthonous carbon to fuel R.

Scale and legacy controls on catchment nutrient export regimes

Science.gov (United States)

Howden, N. J. K.; Burt, T.; Worrall, F.

2017-12-01

Nutrient dynamics in river catchments are complex: water and chemical fluxes are highly variable in low-order streams, but this variability declines as fluxes move through higher-order reaches. This poses a major challenge for process understanding as much effort is focussed on long-term monitoring of the main river channel (a high-order reach), and therefore the data available to support process understanding are predominantly derived from sites where much of the transient response of nutrient export is masked by the effect of averaging over both space and time. This may be further exacerbated at all scales by the accumulation of legacy nutrient sources in soils, aquifers and pore waters, where historical activities have led to nutrient accumulation where the catchment system is transport limited. Therefore it is of particular interest to investigate how the variability of nutrient export changes both with catchment scale (from low to high-order catchment streams) and with the presence of legacy sources, such that the context of infrequent monitoring on high-order streams can be better understood. This is not only a question of characterising nutrient export regimes per se, but also developing a more thorough understanding of how the concepts of scale and legacy may modify the statistical characteristics of observed responses across scales in both space and time. In this paper, we use synthetic data series and develop a model approach to consider how space and timescales combine with impacts of legacy sources to influence observed variability in catchment export. We find that: increasing space and timescales tend to reduce the observed variance in nutrient exports, due to an increase in travel times and greater mixing, and therefore averaging, of sources; increasing the influence of legacy sources inflates the variance, with the level of inflation dictated by the residence time of the respective sources.

EFECTOS BENEFICOS DE BACTERIAS RIZOSFÉRICAS EN LA DISPONIBILIDAD DE NUTRIENTES EN EL SUELO Y LA ABSORCIÓN DE NUTRIENTES POR LAS PLANTAS A REVIEW ON BENEFICIAL EFFECTS OF RHIZOSPHERE BACTERIA ON SOIL NUTRIENT AVAILABILITY AND PLANT NUTRIENT UPTAKE

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Nelson Walter Osorio Vega

2007-06-01

Full Text Available Este artículo se constituye en una revisión de los beneficios de bacterias rizosféricas sobre la nutrición vegetal. La interacción entre planta y bacterias solubilizadoras de fosfato es explicada en mayor detalle y usada como modelo para ilustrar el rol que algunas bacterias de la rizosfera juegan en la disponibilidad de nutrientes en el suelo. Las condiciones ambientales de la rizosfera también se discuten con detalle. Los beneficios de estas bacterias han sido obtenidos, y mejorados, en presencia de hongos formadores de micorrizas. Algunos autores han acuñado el termino “micorrizosfera” para describir la parte del suelo afectada por estas interacciones. Las plantas pueden liberar carbohidratos, aminoácidos, lípidos y vitaminas, entre otros, a través de sus raíces y estimular con ello la actividad y el número de microorganismos del suelo que las rodea. Este volumen de suelo afectado por tales exudados, aproximadamente 2 mm desde la superficie de la raíz, es llamado rizosfera. Las bacterias rizosfericas participan en el ciclo geoquímico de nutrientes y determinan su disponibilidad para las plantas y la comunidad microbial del suelo. Por ejemplo, en la rizosfera algunas bacterias fijan N2 simbiótica o asociativamente, otras son importantes en la conversión del nitrógeno de compuestos orgánicos a formas inorgánicas (NH4+ y NO3- disponibles para las plantas. También es relevante la habilidad de algunas bacterias rizosféricas para disolver fosfatos insolubles (nativo y aplicado a través de ácidos orgánicos, mientras que otras son más activas en la liberación de fosfato de compuestos orgánicos mediante enzimas fosfatasas. Por otro lado, la disponibilidad del azufre, hierro, manganeso es afectada por reacciones bioquímicas de oxido-reducción llevadas a cabo por bacterias de la rizosfera. De la misma manera, agentes quelatantes liberados por estas bacterias controlan la disponibilidad y absorción de micronutrientes y

Assessing Nutrients Availability of Irradiated and Non-Irradiated Biosolids for the Agriculture Re-use

Energy Technology Data Exchange (ETDEWEB)

Magnavacca, Cecilia; Sanchez, Monica

2003-07-01

Irradiation provides a fast and reliable means to disinfect biosolids generated by municipal wastewater treatment processes. The chemical integrity of some substances may be altered thus change the availability of plant nutrients. Chemical analyses on the biosolids showed a release of mineral forms of Nitrogen while Phosphorus chemical forms were not altered. Higher amounts of mineralized N were indirectly demonstrated in soils with irradiated biosolids by a respiration experiment, and higher nitrate concentrations were measured in the irradiated biosolids amended soils at field experiments. Crop field experiments (lettuce and sugarcane) confirmed that irradiated biosolids have higher fertilizing capability than equal amounts of non-irradiated biosolids. Maximum dose rate had no additive effect but a depleted result, thus marking the importance of the use of moderate biosolids rates. (author)

The role of Juncus effusus litter quality and nutrient availability on organic matter decomposition in restored cutover bogs

Science.gov (United States)

Agethen, Svenja; Knorr, Klaus-Holger

2017-04-01

More than 90% of peatlands in Europe are degraded by drainage and subsequent land use. However, beneficial effects of functioning peatlands, most of all carbon storage, have long been recognized but remain difficult to recover. Fragmentation and a surrounding of intensively used agricultural catchments with excess nutrients in air and waters further affects the recovery of sites. Under such conditions, highly competitive species such as Juncus effusus colonize restored peatlands instead of peat forming Sphagnum. While the specific stoichiometry and chemical composition makes Sphagnum litter recalcitrant in decomposition and hence, effective in carbon sequestration, we know little about dynamics involving Juncus, although this species provides organic matter in high quantity and of rather labile quality. To better understand decomposition in context of litter quality and nutrient availability, we incubated different peat types for 70 days; I) recent, II) weakly degraded fossil, and III) earthyfied nutrient rich fossil peat, amended with two 13C pulse-labelled Juncus litter types (excessively fertilized "F", and nutrient poor "NF" plants grown for three years watered with MilliQ only), respectively. We determined anaerobic decomposition rates, compared potential rates extrapolated from pure materials with measured rates of the mixtures, and tracked the 13C in the solid, liquid, and gaseous phase. To characterize the biogeochemical conditions, inorganic and organic electron acceptors, hydrogen and organic acids, and total enzyme activity were monitored. For characterization of dissolved organic matter we used UV-Vis and fluorescence spectroscopy (parallel factor analysis), and for solid organic matter elemental analysis and FTIR spectroscopy. There were two main structural differences between litter types: "F" litter and its leachates contained more proteinaceous components, the C/N ratio was 20 in contrast to 60 of the "NF" litter. However, humic components and

Study on biofiltration capacity and kinetics of nutrient uptake by Gracilaria cervicornis (Turner J. Agardh (Rhodophyta, Gracilariaceae

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Marcella A. A. Carneiro

2011-04-01

Full Text Available The absorption efficiency and kinetic parameters (Vmax, Ks and Vmax:Ks of the seaweed Gracilaria cervicornis for the nutrients NH4+, NO3- and PO4(3- were evaluated. Absorption efficiency was measured by monitoring nutrient concentrations for 5 h in culture media with initial concentrations of 5, 10, 20 and 30µM. Kinetic parameters were determined by using the Michaelis-Menten formula. Absorption efficiencies for this algae were greater in treatments with lower concentrations, as evidenced by a reduction of 85.3, 97.5 and 81.2% for NH4+, NO3- and PO4(3-, respectively. Kinetic parameters show that G. cervicornis exhibits greater ability to take up high concentrations of NH4+ (Vmax=158.5µM g dw-1 h-1 and low concentrations of PO4(3- (Ks=5µM and Vmax:Ks=10.3. These results suggest that this algal species has good absorption capacity for the nutrients tested and may be a promising candidate as a bioremediator of eutrophized environments.

Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community

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K. Sugie

2013-10-01

Full Text Available Little is known concerning the effect of CO2 on phytoplankton ecophysiological processes under nutrient and trace element-limited conditions, because most CO2 manipulation experiments have been conducted under elements-replete conditions. To investigate the effects of CO2 and iron availability on phytoplankton ecophysiology, we conducted an experiment in September 2009 using a phytoplankton community in the iron limited, high-nutrient, low-chlorophyll (HNLC region of the Bering Sea basin . Carbonate chemistry was controlled by the bubbling of the several levels of CO2 concentration (180, 380, 600, and 1000 ppm controlled air, and two iron conditions were established, one with and one without the addition of inorganic iron. We demonstrated that in the iron-limited control conditions, the specific growth rate and the maximum photochemical quantum efficiency (Fv/Fm of photosystem (PS II decreased with increasing CO2 levels, suggesting a further decrease in iron bioavailability under the high-CO2 conditions. In addition, biogenic silica to particulate nitrogen and biogenic silica to particulate organic carbon ratios increased from 2.65 to 3.75 and 0.39 to 0.50, respectively, with an increase in the CO2 level in the iron-limited controls. By contrast, the specific growth rate, Fv/Fm values and elemental compositions in the iron-added treatments did not change in response to the CO2 variations, indicating that the addition of iron canceled out the effect of the modulation of iron bioavailability due to the change in carbonate chemistry. Our results suggest that high-CO2 conditions can alter the biogeochemical cycling of nutrients through decreasing iron bioavailability in the iron-limited HNLC regions in the future.

Modelling nutrient cycling in forest ecosystems; Modellering av naeringssyklus i skogoekosystemer

Energy Technology Data Exchange (ETDEWEB)

Kvindesland, Sheila H.S.B.

1997-12-31

Acid deposition`s threat to fresh water and forest environments became an issue in the late 1960s. Acid deposition and forest nutrient cycling then began to be researched in greater co-operation. This thesis studies nutrient cycling processes in Norway spruce forests, emphasizing the effects on soil chemical properties, soil solution chemistry and streamwater chemistry. It investigates the effects of different aged stands on nutrient cycling and sets up nutrient budgets of the base cations and nitrogen at two sites in Norway. It also selects, documents, calibrates, tests and improves nutrient cycling models for use in Norwegian forests. 84 refs., 44 figs., 46 tabs.

Nutrient management for rice production

International Nuclear Information System (INIS)

Khan, A.R.; Chandra, D.; Nanda, P.; Singh, S.S.; Singh, S.R.; Ghorai, A.K.

2002-06-01

The nutrient removed by the crops far exceeds the amounts replenished through fertilizer, causing a much greater strain on the native soil reserves. The situation is further aggravated in countries like India, where sub-optimal fertilizer used by the farmers is a common phenomenon rather than an exception. The total consumption of nutrients of all crops in India, even though reached 15 million tons in 1997, remains much below the estimated nutrient removal of 25 million tons (Swarup and Goneshamurthy, 1998). The gap between nutrient removal supplied through fertilizer has widened further in 2000 to 34 million tons of plant nutrients from the soil against an estimated fertilizer availability of 18 million tons (Singh and Dwivedi, 1996). Nitrogen is the nutrient which limits the most the rice production worldwide. In Asia, where more than 90 percent of the world's rice is produced, about 60 percent of the N fertilizer consumed is used on rice (Stangel and De Dutta, 1985). Conjunctive use of organic material along with fertilizer has been proved an efficient source of nitrogen. Organic residue recycling is becoming an increasingly important aspect of environmentally sound sustainable agriculture. Returning residues like green manure to the soil is necessary for maintaining soil organic matter, which is important for favourable soil structure, soil water retention and soil microbial flora and fauna activities. Use of organic manures in conjunction or as an alternative to chemical fertilizer is receiving attention. Green manure, addition to some extent, helps not only in enhancing the yield but also in improving the physical and chemical nature of soils. The excessive application of chemical fertilizers made it imperative that a part of inorganic fertilizer may be substituted with the recycling of organic wastes. Organic manure has been recorded to enhance the efficiency and reduce the requirement of chemical fertilizers. Partial nitrogen substitution through organic

Nutrient availability constrains the hydraulic architecture and water relations of savannah trees.

Science.gov (United States)

S.J. Bucci; F.G. Scholz; G. Goldstein; F.C. Meinzer; A.C. Franco; P.I. Campanello; R. Villalobos-Vega; M. Bustamante; F. Miralles-Wilhelm

2006-01-01

Several plant functional traits were studied in five dominant woody savanna species in a Brazilian savanna to determine whether removal of nutrient limitations has an effect on carbon allocation, water relations, and hydraulic architecture. Four treatments consisting of a control, and nitrogen (N), phosphorus (P), and N plus P additions were maintained for 5 years....

A new hammer to crack an old nut: interspecific competitive resource capture by plants is regulated by nutrient supply, not climate.

Directory of Open Access Journals (Sweden)

Clare J Trinder

Full Text Available Although rarely acknowledged, our understanding of how competition is modulated by environmental drivers is severely hampered by our dependence on indirect measurements of outcomes, rather than the process of competition. To overcome this, we made direct measurements of plant competition for soil nitrogen (N. Using isotope pool-dilution, we examined the interactive effects of soil resource limitation and climatic severity between two common grassland species. Pool-dilution estimates the uptake of total N over a defined time period, rather than simply the uptake of ¹⁵N label, as used in most other tracer experiments. Competitive uptake of N was determined by its available form (NO₃⁻ or NH₄⁺. Soil N availability had a greater effect than the climatic conditions (location under which plants grew. The results did not entirely support either of the main current theories relating the role of competition to environmental conditions. We found no evidence for Tilman's theory that competition for soil nutrients is stronger at low, compared with high nutrient levels and partial support for Grime's theory that competition for soil nutrients is greater under potentially more productive conditions. These results provide novel insights by demonstrating the dynamic nature of plant resource competition.

Grand Fir Nutrient Management in the Inland Northwestern USA

Directory of Open Access Journals (Sweden)

Dennis R. Parent

2016-11-01

Full Text Available Grand fir (Abies grandis (Douglas ex D. Don Lindley is widely distributed in the moist forests of the Inland Northwest. It has high potential productivity, its growth being nearly equal to western white pine, the most productive species in the region. There are large standing volumes of grand fir in the region. Nutritionally, the species has higher foliage cation concentrations than associated conifers, especially potassium (K and calcium (Ca. In contrast, it has lower nitrogen (N foliage concentrations, which creates favorable nutrient balance on N-limited sites. Despite concentration differences, grand fir stores proportionally more nutrients per tree than associated species because of greater crown biomass. Although few fertilization trials have examined grand fir specifically, its response is inferred from its occurrence in many monitored mixed conifer stands. Fertilization trials including grand fir either as a major or minor component show that it has a strong diameter and height growth response ranging from 15% to 50% depending in part on site moisture availability and soil geology. Grand fir tends to have a longer response duration than other inland conifers. When executed concurrently with thinning, fertilization often increases the total response. Late rotation application of N provides solid investment returns in carefully selected stands. Although there are still challenges with the post-fertilization effects on tree mortality, grand fir will continue to be an important species with good economic values and beneficial responses to fertilization and nutrient management.

Particle water and pH in the Eastern Mediterranean: sources variability and implications for nutrients availability

Science.gov (United States)

Nikolaou, P.; Bougiatioti, A.; Stavroulas, I.; Kouvarakis, G.; Nenes, A.; Weber, R.; Kanakidou, M.; Mihalopoulos, N.

2015-10-01

during early morning, late evening and nighttime hours. The aerosol was found to be highly acidic with calculated aerosol pH varying from 0.5 to 2.8 throughout the study period. Biomass burning aerosol presented the highest values of pH in the submicron fraction and the lowest values in total water mass concentration. The low pH values observed in the submicron mode and independently of air masses origin could increase nutrient availability and especially P solubility, which is the nutrient limiting sea water productivity of the eastern Mediterranean.

Particle water and pH in the eastern Mediterranean: source variability and implications for nutrient availability

Science.gov (United States)

Bougiatioti, Aikaterini; Nikolaou, Panayiota; Stavroulas, Iasonas; Kouvarakis, Giorgos; Weber, Rodney; Nenes, Athanasios; Kanakidou, Maria; Mihalopoulos, Nikolaos

2016-04-01

contributed about 27.5 % to the total aerosol water, mostly during early morning, late evening, and nighttime hours.The aerosol was found to be highly acidic with calculated aerosol pH varying from 0.5 to 2.8 throughout the study period. Biomass burning aerosol presented the highest values of pH in the submicron fraction and the lowest values in total water mass concentration. The low pH values observed in the submicron mode and independently of air mass origin could increase nutrient availability and especially P solubility, which is the nutrient limiting sea water productivity of the eastern Mediterranean.

Neutral detergent fibre in piglet diets: digestibility, performance, and deposition of body nutrients

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RAFAEL C. NEPOMUCENO

2017-12-01

Full Text Available ABSTRACT A total 120 piglets with an average live weight of 7.00 kg, weaned at 21 days, were used to evaluate the effect of neutral detergent fibre levels on the digestibility of nutrients and energy from the diets, productive performance, and the composition and rate of deposition of nutrients and energy in the bodies of piglets in the nursery phase. The animals were distributed according to a randomized-block design into five treatments, which consisted of neutral detergent fibre levels, with six replicates and four animals per plot. A quadratic effect was detected for the digestibility coefficients of nutrients and energy, feed intake and weight gain. The increase in fibre level promoted a linear increase in fat content in the carcass, blood, and body, whereas the energy in the carcass, organs, and body showed an inverse response. The results showed a quadratic effect on the nutrient deposition rate in the carcass, organs and body. In conclusion, the best digestibility of nutrients and energy from the diet is obtained with 10-11.5% neutral detergent fibre, as higher weight gain and greater protein deposition in the body are achieved at neutral detergent fibre levels of 10.6% and 10.3%, respectively.

Biological response to millennial variability of dust and nutrient supply in the Subantarctic South Atlantic Ocean.

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Anderson, Robert F; Barker, Stephen; Fleisher, Martin; Gersonde, Rainer; Goldstein, Steven L; Kuhn, Gerhard; Mortyn, P Graham; Pahnke, Katharina; Sachs, Julian P

2014-07-13

Fluxes of lithogenic material and fluxes of three palaeo-productivity proxies (organic carbon, biogenic opal and alkenones) over the past 100,000 years were determined using the (230)Th-normalization method in three sediment cores from the Subantarctic South Atlantic Ocean. Features in the lithogenic flux record of each core correspond to similar features in the record of dust deposition in the EPICA Dome C ice core. Biogenic fluxes correlate with lithogenic fluxes in each sediment core. Our preferred interpretation is that South American dust, most probably from Patagonia, constitutes a major source of lithogenic material in Subantarctic South Atlantic sediments, and that past biological productivity in this region responded to variability in the supply of dust, probably due to biologically available iron carried by the dust. Greater nutrient supply as well as greater nutrient utilization (stimulated by dust) contributed to Subantarctic productivity during cold periods, in contrast to the region south of the Antarctic Polar Front (APF), where reduced nutrient supply during cold periods was the principal factor limiting productivity. The anti-phased patterns of productivity on opposite sides of the APF point to shifts in the physical supply of nutrients and to dust as cofactors regulating productivity in the Southern Ocean. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The Nutrient Density of Snacks

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Julie Hess BA

2017-03-01

Full Text Available Background: Although Americans receive almost a quarter of their daily energy from snacks, snacking remains a poorly defined and understood eating occasion. However, there is little dietary guidance about choosing snacks. Families, clinicians, and researchers need a comprehensive approach to assessing their nutritional value. Objective: To quantify and compare the nutrient density of commonly consumed snacks by their overall nutrient profiles using the Nutrient-Rich Foods (NRF Index 10.3. Methods: NRF Index scores were calculated for the top 3 selling products (based on 2014 market research data in different snack categories. These NRF scores were averaged to provide an overall nutrient-density score for each category. Results: Based on NRF scores, yogurt (55.3, milk (52.5, and fruit (30.1 emerged as the most nutrient-dense snacks. Ice cream (−4.4, pies and cakes (−11.1, and carbonated soft drinks (−17.2 emerged as the most nutrient-poor snacks. Conclusions: The NRF Index is a useful tool for assessing the overall nutritional value of snacks based on nutrients to limit and nutrients to encourage.

Measuring nutrient spiralling in streams

Energy Technology Data Exchange (ETDEWEB)

Newbold, J D; Elwood, J W; O' Neill, R V; Van Winkle, W

1981-01-01

Nutrient cycling in streams involves some downstream transport before the cycle is completed. Thus, the path traveled by a nutrient atom in passing through the cycle can be visualized as a spiral. As an index of the spiralling process, we introduce spiralling length, defined as the average distance associated with one complete cycle of a nutrient atom. This index provides a measure of the utilization of nutrients relative to the available supply from upstream. Using /sup 32/p as a tracer, we estimated a spiralling length of 193 m for phosphorus in a small woodland stream.

The potential of freshwater macroalgae as a biofuels feedstock and the influence of nutrient availability on freshwater macroalgal biomass production

Science.gov (United States)

Yun, Jin-Ho

Extensive efforts have been made to evaluate the potential of microalgae as a biofuel feedstock during the past 4-5 decades. However, filamentous freshwater macroalgae have numerous characteristics that favor their potential use as an alternative algal feedstock for biofuels production. Freshwater macroalgae exhibit high rates of areal productivity, and their tendency to form dense floating mats on the water surface imply significant reductions in harvesting and dewater costs compared to microalgae. In Chapter 1, I reviewed the published literature on the elemental composition and energy content of five genera of freshwater macroalgae. This review suggested that freshwater macroalgae compare favorably with traditional bio-based energy sources, including terrestrial residues, wood, and coal. In addition, I performed a semi-continuous culture experiment using the common Chlorophyte genus Oedogonium to investigate whether nutrient availability can influence its higher heating value (HHV), productivity, and proximate analysis. The experimental study suggested that the most nutrient-limited growth conditions resulted in a significant increase in the HHV of the Oedogonium biomass (14.4 MJ/kg to 16.1 MJ/kg). Although there was no significant difference in productivity between the treatments, the average dry weight productivity of Oedogonium (3.37 g/m2/day) was found to be much higher than is achievable with common terrestrial plant crops. Although filamentous freshwater macroalgae, therefore, have significant potential as a renewable source of bioenergy, the ultimate success of freshwater macroalgae as a biofuel feedstock will depend upon the ability to produce biomass at the commercial-scale in a cost-effective and sustainable manner. Aquatic ecology can play an important role to achieve the scale-up of algal crop production by informing the supply rates of nutrients to the cultivation systems, and by helping to create adaptive production systems that are resilient to

Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes

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Jon eTelling

2014-12-01

Full Text Available The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw towards fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus with longer isolation age. During the initial melt there was a mean nine times enrichment in dissolved chloride relative to mean concentrations of the initial frozen holes indicative of an ionic pulse, with similar mean nine times enrichments in nitrite, ammonium, and dissolved organic matter. Nitrate was enriched twelve times and dissolved organic nitrogen six times, suggesting net nitrification, while lower enrichments for dissolved organic phosphorus and phosphate were consistent with net microbial phosphorus uptake. Rates of bacterial production were significantly elevated during the ionic pulse, likely due to the increased nutrient availability. There was no concomitant increase in photosynthesis rates, with a net depletion of dissolved inorganic carbon suggesting inorganic carbon limitation. Potential nitrogen fixation was detected in fully melted holes where it could be an important source of nitrogen to support microbial growth, but not during the ionic pulse where nitrogen availability was higher. This study demonstrates that ionic pulses significantly alter the timing and magnitude of microbial activity within entombed cryoconite holes, and adds credence to hypotheses that ionic enrichments during freeze-thaw can elevate rates of microbial growth and activity in other icy habitats, such as ice veins and

Radiation-use efficiency and gas exchange responses to water and nutrient availability in irrigated and fertilized stands of sweetgum and sycamore

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Christopher B. Allen; Rodney E. Will; Robert C. McGravey; David R. Coyle; Mark D. Coleman

2005-01-01

We investigated how water and nutrient availability affect radiation-use effeciency (e) and assessed leaf gas exchange as a possible mechanism for shifts in e. We measured aboveground net primary production (ANPP) and annual photosynthetically active radiation (PAR) capture to calculate e as well as leaf-level physiological variables (light-saturated net photosynthesis...

Leaf mineral nutrient remobilization during leaf senescence and modulation by nutrient deficiency.

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Anne eMaillard

2015-05-01

Full Text Available Higher plants have to cope with fluctuating mineral resource availability. However strategies such as stimulation of root growth, increased transporter activities, and nutrient storage and remobilization have been mostly studied for only a few macronutrients. Leaves of cultivated crops (Zea mays, Brassica napus, Pisum sativum, Triticum aestivum, Hordeum vulgare and tree species (Quercus robur, Populus nigra, Alnus glutinosa grown under field conditions were harvested regularly during their life span and analysed to evaluate the net mobilization of 13 nutrients during leaf senescence. While N was remobilized in all plant species with different efficiencies ranging from 40% (maize to 90% (wheat, other macronutrients (K-P-S-Mg were mobilized in most species. Ca and Mn, usually considered as having low phloem mobility were remobilized from leaves in wheat and barley. Leaf content of Cu-Mo-Ni-B-Fe-Zn decreased in some species, as a result of remobilization. Overall, wheat, barley and oak appeared to be the most efficient at remobilization while poplar and maize were the least efficient. Further experiments were performed with rapeseed plants subjected to individual nutrient deficiencies. Compared to field conditions, remobilization from leaves was similar (N-S-Cu or increased by nutrient deficiency (K-P-Mg while nutrient deficiency had no effect on Mo-Zn-B-Ca-Mn, which seemed to be non-mobile during leaf senescence under field conditions. However, Ca and Mn were largely mobilized from roots (-97 and -86% of their initial root contents, respectively to shoots. Differences in remobilization between species and between nutrients are then discussed in relation to a range of putative mechanisms.

Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

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Black, R.W.; Moran, P.W.; Frankforter, J.D.

2011-01-01

Many streams within the United States are impaired due to nutrient enrichment, particularly in agricultural settings. The present study examines the response of benthic algal communities in agricultural and minimally disturbed sites from across the western United States to a suite of environmental factors, including nutrients, collected at multiple scales. The first objective was to identify the relative importance of nutrients, habitat and watershed features, and macroinvertebrate trophic structure to explain algal metrics derived from deposition and erosion habitats. The second objective was to determine if thresholds in total nitrogen (TN) and total phosphorus (TP) related to algal metrics could be identified and how these thresholds varied across metrics and habitats. Nutrient concentrations within the agricultural areas were elevated and greater than published threshold values. All algal metrics examined responded to nutrients as hypothesized. Although nutrients typically were the most important variables in explaining the variation in each of the algal metrics, environmental factors operating at multiple scales also were important. Calculated thresholds for TN or TP based on the algal metrics generated from samples collected from erosion and deposition habitats were not significantly different. Little variability in threshold values for each metric for TN and TP was observed. The consistency of the threshold values measured across multiple metrics and habitats suggest that the thresholds identified in this study are ecologically relevant. Additional work to characterize the relationship between algal metrics, physical and chemical features, and nuisance algal growth would be of benefit to the development of nutrient thresholds and criteria. ?? 2010 The Author(s).

Convenience stores are the key food environment influence on nutrients available from household food supplies in Texas Border Colonias

OpenAIRE

Sharkey, Joseph R; Dean, Wesley R; Nalty, Courtney C; Xu, Jin

2013-01-01

Abstract Background Few studies have focused on the relationship between the retail food environment and household food supplies. This study examines spatial access to retail food stores, food shopping habits, and nutrients available in household food supplies among 50 Mexican-origin families residing in Texas border colonias. Methods The design was cross-sectional; data were collected in the home March to June 2010 by promotora-researchers. Ground-truthed methods enumerated traditional (supe...

Improving crop nutrient efficiency through root architecture modifications.

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Li, Xinxin; Zeng, Rensen; Liao, Hong

2016-03-01

Improving crop nutrient efficiency becomes an essential consideration for environmentally friendly and sustainable agriculture. Plant growth and development is dependent on 17 essential nutrient elements, among them, nitrogen (N) and phosphorus (P) are the two most important mineral nutrients. Hence it is not surprising that low N and/or low P availability in soils severely constrains crop growth and productivity, and thereby have become high priority targets for improving nutrient efficiency in crops. Root exploration largely determines the ability of plants to acquire mineral nutrients from soils. Therefore, root architecture, the 3-dimensional configuration of the plant's root system in the soil, is of great importance for improving crop nutrient efficiency. Furthermore, the symbiotic associations between host plants and arbuscular mycorrhiza fungi/rhizobial bacteria, are additional important strategies to enhance nutrient acquisition. In this review, we summarize the recent advances in the current understanding of crop species control of root architecture alterations in response to nutrient availability and root/microbe symbioses, through gene or QTL regulation, which results in enhanced nutrient acquisition. © 2015 Institute of Botany, Chinese Academy of Sciences.

Effects of feeding frequency on apparent energy and nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal and suboptimal temperatures

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This study examined the effects of feeding frequency (daily versus every other day [EOD]) on nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal (30 C) and suboptimal (24 C) temperatures. A 28% protein practical diet was used as the test diet, and chromic o...

Nutrient sensing and TOR signaling in yeast and mammals.

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González, Asier; Hall, Michael N

2017-02-15

Coordinating cell growth with nutrient availability is critical for cell survival. The evolutionarily conserved TOR (target of rapamycin) controls cell growth in response to nutrients, in particular amino acids. As a central controller of cell growth, mTOR (mammalian TOR) is implicated in several disorders, including cancer, obesity, and diabetes. Here, we review how nutrient availability is sensed and transduced to TOR in budding yeast and mammals. A better understanding of how nutrient availability is transduced to TOR may allow novel strategies in the treatment for mTOR-related diseases. © 2017 The Authors.

Amazon forest ecosystem responses to elevated atmospheric CO2 and alterations in nutrient availability: filling the gaps with model-experiment integration

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Florian eHofhansl

2016-02-01

Full Text Available The impacts of elevated CO2 (eCO2 and alterations in nutrient availability on the carbon (C storage capacity and resilience of the Amazon forest remain highly uncertain. Carbon dynamics are controlled by multiple eco-physiological processes responding to environmental change, but we lack solid experimental evidence, hampering theory development and thus representation in ecosystem models. Here, we present two ecosystem-scale manipulation experiments, to be carried out in the Amazon, that examine tropical ecosystem responses to eCO2 and nutrient addition and thus will elucidate the representation of crucial ecological processes by ecosystem models. We highlight current gaps in our understanding of tropical ecosystem responses to projected global changes in light of the eco-physiological assumptions considered by current ecosystem models. We conclude that a more detailed process-based representation of the spatial (e.g. soil type; plant functional type and temporal (seasonal and inter-annual variation diversity of tropical forests is needed to enhance model predictions of ecosystem responses to projected global environmental change.

Influence of Acacia trees on soil nutrient levels in arid lands

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De Boever, Maarten; Gabriels, Donald; Ouessar, Mohamed; Cornelis, Wim

2014-05-01

The potential of scattered trees as keystone structures in restoring degraded environments is gaining importance. Scattered trees have strong influence on their abiotic environment, mainly causing changes in microclimate, water budget and soil properties. They often function as 'nursing trees', facilitating the recruitment of other plants. Acacia raddiana is such a keystone species which persists on the edge of the Sahara desert. The study was conducted in a forest-steppe ecosystem in central Tunisia where several reforestation campaigns with Acacia took place. To indentify the impact of those trees on soil nutrients, changes in nutrient levels under scattered trees of three age stages were examined for the upper soil layer (0-10 cm) at five microsites with increasing distance from the trunk. In addition, changes in soil nutrient levels with depth underneath and outside the canopy were determined for the 0-30 cm soil layer. Higher concentrations of organic matter (OM) were found along the gradient from underneath to outside the canopy for large trees compared to medium and small trees, especially at microsites close to the trunk. Levels of soluble K, electrical conductivity (EC), available P, OM, total C and N decreased whereas pH and levels of soluble Mg increased with increasing distance from tree. Levels of soluble Ca and Na remained unchanged along the gradient. At the microsite closest to the trunk a significant decrease in levels of soluble K, EC, OM, available P, total C and N, while a significant increase in pH was found with increasing depth. The concentration of other nutrients remained unchanged or declined not differently underneath compared to outside the canopy with increasing depth. Differences in nutrient levels were largely driven by greater inputs of organic matter under trees. Hence, Acacia trees can affect the productivity and reproduction of understory species with the latter in term an important source of organic matter. This positive feedback

Food Availability in School Stores in Seoul, South Korea after Implementation of Food- and Nutrient-Based Policies

Science.gov (United States)

Choi, Seul Ki; Frongillo, Edward A.; Blake, Christine E.; Thrasher, James F.

2017-01-01

Background: To improve school store food environments, the South Korean government implemented 2 policies restricting unhealthy food sales in school stores. A food-based policy enacted in 2007 restricts specific food sales (soft drinks); and a nutrient-based policy enacted in 2009 restricts energy-dense and nutrient-poor (EDNP) food sales. The…

Home availability of fruit and vegetables and obesogenic foods as an indicator of nutrient intake in 50 year olds from Canterbury, New Zealand.

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Grant, Emily; Gearry, Richard Blair; Wilson, Renée; Pearson, John; Skidmore, Paula Marie Louise

2017-05-01

The home food environment is known to influence children's diet and selected health outcomes. However, similar research in adults is scarce. The home is arguably the most important food environment for New Zealand adults as the majority of food consumed is stored and prepared in the home. Therefore we investigated relationships between home food availability and nutrient intake in 50 year olds from Canterbury, New Zealand. A cross-sectional study where participants completed a home food inventory and a four-day estimated food diary. Regression analysis was used to investigate relationships between home availability of 'Fruit and Vegetables' and 'Obesogenic Foods' and intake of selected nutrients, adjusting for Body Mass Index and demographic factors. Men and women (n=216) aged 50 were randomly selected from Canterbury District Health Board area electoral rolls. Women with a high 'Obesogenic Foods' score were significantly more likely to have a high intake of saturated fat (OR 5.8, CI: 1.67, 19.6) and high sugar intake (OR 3.1, CI: 1.23, 7.58). Men with a high 'Obesogenic Foods' score were less likely to have high folate (OR 0.14, CI: 0.05, 0.40) and fibre intake (OR 0.21, CI: 0.07, 0.60). Men and women with a higher 'Fruit and Vegetables' score were more likely to have high vitamin C intake (OR 5.6 and 4.5 respectively). Home Food Inventory scores are associated with selected nutrient intakes, particularly in women, suggesting that they are useful for identifying those groups with less favourable nutrient intakes. Future research should investigate whether these scores can predict health outcomes.

Ultrastructural biomarkers in symbiotic algae reflect the availability of dissolved inorganic nutrients and particulate food to the reef coral holobiont

OpenAIRE

Sabrina eRosset; Cecilia eD'Angelo; Jörg eWiedenmann; Jörg eWiedenmann

2015-01-01

Reef building corals associated with symbiotic algae (zooxanthellae) can access environmental nutrients from different sources, most significantly via the uptake of dissolved inorganic nutrients by the algal symbiont and heterotrophic feeding of the coral host. Climate change is expected to alter the nutrient environment in coral reefs with the potential to benefit or disturb coral reef resilience. At present, the relative importance of the two major nutrient sources is not well understood, m...

Ultra-processed foods have the worst nutrient profile, yet they are the most available packaged products in a sample of New Zealand supermarkets

NARCIS (Netherlands)

Luiten, Claire M; Steenhuis, Ingrid Hm; Eyles, Helen; Ni Mhurchu, Cliona; Waterlander, Wilma E

OBJECTIVE: To examine the availability of packaged food products in New Zealand supermarkets by level of industrial processing, nutrient profiling score (NPSC), price (energy, unit and serving costs) and brand variety. DESIGN: Secondary analysis of cross-sectional survey data on packaged supermarket

Ultra-processed foods have the worst nutrient profile, yet they are the most available packaged products in a sample of New Zealand supermarkets.

Science.gov (United States)

Luiten, Claire M; Steenhuis, Ingrid Hm; Eyles, Helen; Ni Mhurchu, Cliona; Waterlander, Wilma E

2016-02-01

To examine the availability of packaged food products in New Zealand supermarkets by level of industrial processing, nutrient profiling score (NPSC), price (energy, unit and serving costs) and brand variety. Secondary analysis of cross-sectional survey data on packaged supermarket food and non-alcoholic beverages. Products were classified according to level of industrial processing (minimally, culinary and ultra-processed) and their NPSC. Packaged foods available in four major supermarkets in Auckland, New Zealand. Packaged supermarket food products for the years 2011 and 2013. The majority (84% in 2011 and 83% in 2013) of packaged foods were classified as ultra-processed. A significant positive association was found between the level of industrial processing and NPSC, i.e., ultra-processed foods had a worse nutrient profile (NPSC=11.63) than culinary processed foods (NPSC=7.95), which in turn had a worse nutrient profile than minimally processed foods (NPSC=3.27), Pprice measures and level of processing. The study observed many variations of virtually the same product. The ten largest food manufacturers produced 35% of all packaged foods available. In New Zealand supermarkets, ultra-processed foods comprise the largest proportion of packaged foods and are less healthy than less processed foods. The lack of significant price difference between ultra- and less processed foods suggests ultra-processed foods might provide time-poor consumers with more value for money. These findings highlight the need to improve the supermarket food supply by reducing numbers of ultra-processed foods and by reformulating products to improve their nutritional profile.

A new hammer to crack an old nut: interspecific competitive resource capture by plants is regulated by nutrient supply, not climate.

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Trinder, Clare J; Brooker, Rob W; Davidson, Hazel; Robinson, David

2012-01-01

Although rarely acknowledged, our understanding of how competition is modulated by environmental drivers is severely hampered by our dependence on indirect measurements of outcomes, rather than the process of competition. To overcome this, we made direct measurements of plant competition for soil nitrogen (N). Using isotope pool-dilution, we examined the interactive effects of soil resource limitation and climatic severity between two common grassland species. Pool-dilution estimates the uptake of total N over a defined time period, rather than simply the uptake of ¹⁵N label, as used in most other tracer experiments. Competitive uptake of N was determined by its available form (NO₃⁻ or NH₄⁺). Soil N availability had a greater effect than the climatic conditions (location) under which plants grew. The results did not entirely support either of the main current theories relating the role of competition to environmental conditions. We found no evidence for Tilman's theory that competition for soil nutrients is stronger at low, compared with high nutrient levels and partial support for Grime's theory that competition for soil nutrients is greater under potentially more productive conditions. These results provide novel insights by demonstrating the dynamic nature of plant resource competition.

Effects of mountain agriculture on nutrient cycling at upstream watersheds

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Lin, T.-C.; Shaner, P. L.; Wang, L.-J.; Shih, Y.-T.; Wang, C.-P.; Huang, G.-H.; Huang, J.-C.

2015-05-01

The expansion of agriculture to rugged mountains can exacerbate negative impacts of agriculture activities on ecosystem function. In this study, we monitored streamwater chemistry of four watersheds with varying proportions of agricultural lands (0.4, 3, 17, 22%) and rainfall chemistry of two of the four watersheds at Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found that the greater the proportions of agricultural lands, the higher the ion concentrations, which is evident for fertilizer-associated ions (NO3-, K+) but not for ions that are rich in soils (SO42-, Ca2+, Mg2+), suggesting that agriculture enriched fertilizer-associated nutrients in streamwater. The watershed with the highest proportion of agricultural lands had higher concentrations of ions in rainfall and lower nutrient retention capacity (i.e. higher output-input ratio of ions) compared to the relatively pristine watershed, suggesting that agriculture can influence atmospheric deposition of nutrients and a system's ability to retain nutrients. Furthermore, we found that a forested watershed downstream of agricultural activities can dilute the concentrations of fertilizer-associated ions (NO3-, K+) in streamwater by more than 70%, indicating that specific landscape configurations help mitigate nutrient enrichment to aquatic systems. We estimated that agricultural lands at our study site contributed approximately 400 kg ha-1 yr-1 of NO3-N and 260 kg ha-1 yr-1 of PO4-P output via streamwater, an order of magnitude greater than previously reported around the globe and can only be matched by areas under intense fertilizer use. Furthermore, we re-constructed watershed nutrient fluxes to show that excessive leaching of N and P, and additional loss of N to the atmosphere via volatilization and denitrification, can occur under intense fertilizer use. In summary, this study demonstrated the pervasive impacts of agriculture activities

Contrasting nutritional acclimation of sugar maple (Acer saccharum Marsh. and red maple (Acer rubrum L. to increasing conifers and soil acidity as demonstrated by foliar nutrient balances

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Alexandre Collin

2016-07-01

Full Text Available Sugar maple (Acer saccharum Marshall, SM is believed to be more sensitive to acidic and nutrient-poor soils associated with conifer-dominated stands than red maple (Acer rubrum L., RM. Greater foliar nutrient use efficiency (FNUE of RM is likely the cause for this difference. In the context of climate change, this greater FNUE could be key in favouring northward migration of RM over SM. We used the concept of foliar nutrient balances to study the nutrition of SM and RM seedlings along an increasing gradient in forest floor acidity conditioned by increasing proportions of conifers (pH values ranging from 4.39 under hardwoods, to 4.29 under mixed hardwood-conifer stands and 4.05 under conifer-dominated stands. Nutrients were subjected to isometric log-ratio (ilr transformation, which views the leaf as one closed system and considers interactions between nutrients. The ilr method eliminates numerical biases and weak statistical inferences based on raw or operationally’’ log-transformed data. We analyzed foliar nutrients of SM and RM seedlings and found that the [Ca,Mg,K|P,N] and [Ca,Mg|K] balances of SM seedlings were significantly different among soil acidity levels, whereas they did not vary for RM seedlings. For SM seedlings, these differences among soil acidity levels were due to a significant decrease in foliar Ca and Mg concentrations with increasing forest floor acidity. Similar differences in foliar balances were also found between healthy and declining SM stands estimated from literature values. Conversely, foliar balances of RM seedlings did not differ among soil acidity levels, even though untransformed foliar nutrient concentrations were significantly different. This result highlights the importance of using ilr transformation, since it provides more sensitive results than standard testing of untransformed nutrient concentrations. The lower nutrient requirements of RM and its greater capacity to maintain nutrient equilibrium are

Comparative growth behaviour and leaf nutrient status of native trees planted on mine spoil with and without nutrient amendment

Energy Technology Data Exchange (ETDEWEB)

Singh, A.; Singh, J.S. [Banaras Hindu University, Varanasi (India). Dept. of Botany

2001-07-01

The effect of nutrient amendment on growth of nine indigenous tree species planted on coal mine spoil was studied. Greater growth in fertilized plots was accompanied by greater foliar N and P concentrations in all species. The response to fertilization varied among species and was greater in non-leguminous than in leguminous species. Furthermore, leguminous species exhibited higher growth rates compared to non-leguminous species. Acacia catechu, Dalbergia sissoo, Gmelina arborea and Azadirachta indica fitted the elastic similarity model of tree growth; whereas Pongamia pinnata and Phyllanthus emblica followed the constant stress model. Tectona grandis was the only species which fitted the geometric similarity model.

Nutrient uptake dynamics across a gradient of nutrient concentrations and ratios at the landscape scale

Science.gov (United States)

Gibson, Catherine A.; O'Reilly, Catherine M.; Conine, Andrea L.; Lipshutz, Sondra M.

2015-02-01

Understanding interactions between nutrient cycles is essential for recognizing and remediating human impacts on water quality, yet multielemental approaches to studying nutrient cycling in streams are currently rare. Here we utilized a relatively new approach (tracer additions for spiraling curve characterization) to examine uptake dynamics for three essential nutrients across a landscape that varied in absolute and relative nutrient availability. We measured nutrient uptake for soluble reactive phosphorous, ammonium-nitrogen, and nitrate-nitrogen in 16 headwater streams in the Catskill Mountains, New York. Across the landscape, ammonium-nitrogen and soluble reactive phosphorus had shorter uptake lengths and higher uptake velocities than nitrate-nitrogen. Ammonium-nitrogen and soluble reactive phosphorus uptake velocities were tightly correlated, and the slope of the relationship did not differ from one, suggesting strong demand for both nutrients despite the high ambient water column dissolved inorganic nitrogen: soluble reactive phosphorus ratios. Ammonium-nitrogen appeared to be the preferred form of nitrogen despite much higher nitrate-nitrogen concentrations. The uptake rate of nitrate-nitrogen was positively correlated with ambient soluble reactive phosphorus concentration and soluble reactive phosphorus areal uptake rate, suggesting that higher soluble reactive phosphorus concentrations alleviate phosphorus limitation and facilitate nitrate-nitrogen uptake. In addition, these streams retained a large proportion of soluble reactive phosphorus, ammonium-nitrogen, and nitrate-nitrogen supplied by the watershed, demonstrating that these streams are important landscape filters for nutrients. Together, these results (1) indicated phosphorus limitation across the landscape but similarly high demand for ammonium-nitrogen and (2) suggested that nitrate-nitrogen uptake was influenced by variability in soluble reactive phosphorus availability and preference for

Managing Soil Biota-Mediated Decomposition and Nutrient Mineralization in Sustainable Agroecosystems

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Joann K. Whalen

2014-01-01

Full Text Available Transformation of organic residues into plant-available nutrients occurs through decomposition and mineralization and is mediated by saprophytic microorganisms and fauna. Of particular interest is the recycling of the essential plant elements—N, P, and S—contained in organic residues. If organic residues can supply sufficient nutrients during crop growth, a reduction in fertilizer use is possible. The challenge is synchronizing nutrient release from organic residues with crop nutrient demands throughout the growing season. This paper presents a conceptual model describing the pattern of nutrient release from organic residues in relation to crop nutrient uptake. Next, it explores experimental approaches to measure the physical, chemical, and biological barriers to decomposition and nutrient mineralization. Methods are proposed to determine the rates of decomposition and nutrient release from organic residues. Practically, this information can be used by agricultural producers to determine if plant-available nutrient supply is sufficient to meet crop demands at key growth stages or whether additional fertilizer is needed. Finally, agronomic practices that control the rate of soil biota-mediated decomposition and mineralization, as well as those that facilitate uptake of plant-available nutrients, are identified. Increasing reliance on soil biological activity could benefit crop nutrition and health in sustainable agroecosystems.

Effect of multi-nutrient complex fertilizers on growth and tuber yield of very early potato (Solanum tuberosum L. cultivars

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Wanda Wadas

2013-10-01

Full Text Available The aim of the study was to compare the effect of multi-nutrient complex fertilizers (HydroComplex, Nitrophoska Blue Special and Viking 13 from the nitrophoska group, and Polimag S from the amophoska group and single-nutrient fertilizers on the growth and tuber yield of very early potato cultivars (‘Aster’, ‘Fresco’, ‘Gloria’. The field experiment was carried out on podzolic soil in mid-eastern Poland during 2005–2007. The study showed a greater beneficial effect of HydroComplex and Nitrophoska Blue Special on the growth of very early potato cultivars than that of Viking 13 and Polimag S. The application of HydroComplex and Nitrophoska Blue Special resulted in greater above-ground plant biomass and assimilation leaf area compared with single-nutrient fertilizers; the leaf area index (LAI was higher by 0.28 and 0.32, respectively. The differences were smaller and not statistically confirmed with the use of Polimag S and Viking 13. When the multi-nutrient complex fertilizers were applied, leaf weight ratio (LWR, leaf area ratio (LAR and specific leaf area (SLA were similar to the single-nutrient fertilizers. Of the multi-nutrient complex fertilizers, only Nitrophoska Blue Special resulted in higher tuber yield, on average by 2.40 t × ha-1, compared with the single-nutrient fertilizers. The studied cultivars showed a similar response to applied fertilizers. LAI for ‘Gloria’ was higher than for ‘Aster’ and ‘Fresco’, with smaller LAR found in ‘Gloria’. LWR for ‘Fresco’ was smaller than for ‘Aster’ and ‘Gloria’, with higher SLA found in ‘Fresco’. The tuber yield of ‘Aster” (24.04 t × ha-1 was higher on average by 3 t × ha-1 than for ‘Fresco’ and ‘Gloria’.

Estimating photosynthesis with high resolution field spectroscopy in a Mediterranean grassland under different nutrient availability

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Perez-Priego, O.; Guan, J.; Fava, F.; Rossini, M.; Wutzler, T.; Moreno, G.; Carrara, A.; Kolle, O.; Schrumpf, M.; Reichstein, M.; Migliavacca, M.

2014-12-01

Recent studies have shown how human induced N:P imbalances are affecting essential processes (e.g. photosynthesis, plant growth rate) that lead to important changes in ecosystem structure and function. In this regard, the accuracy of the approaches based on remotely-sensed data for monitoring and modeling gross primary production (GPP) relies on the ability of vegetation indices (VIs) to track the dynamics of vegetation physiological and biophysical properties/variables. Promising results have been recently obtained when Chlorophyll-sensitive VIs and Chlorophyll fluorescence are combined with structural indices in the framework of the Monteith's light use efficiency (LUE) model. However, further ground-based experiments are required to validate LUE model performances, and their capability to be generalized under different nutrient availability conditions. In this study, the overall objective was to investigate the sensitivity of VIs to track short- and long-term GPP variations in a Mediterranean grassland under different N and P fertilization treatments. Spectral VIs were acquired manually using high resolution spectrometers (HR4000, OceanOptics, USA) along a phenological cycle. The VIs examined included photochemical reflectance index (PRI), MERIS terrestrial-chlorophyll index (MTCI) and normalized difference vegetation index (NDVI). Solar-induced chlorophyll fluorescence calculated at the oxygen absorption band O2-A (F760) using spectral fitting methods was also used. Simultaneously, measurements of GPP and environmental variables were conducted using a transient-state canopy chamber. Overall, GPP, F760 and VIs showed a clear seasonal time-trend in all treatments, which was driven by the phenological development of the grassland. Results showed significant differences (p<0.05) in midday GPP values between N and without N addition plots, in particular at the peak of the growing season during the flowering stage and at the end of the season during senescence. While

Nutrient Management Approaches and Tools for Dairy farms in Australia and the USA.

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In Australia and the USA, nutrient imports and accumulation on dairy farms can be a problem and may pose a threat to the greater environment. While the major nutrient imports onto dairy farms (i.e. fertilizer and feed) and exports (i.e. milk and animals) are generally the same for confinement-based ...

Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes.

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Telling, Jon; Anesio, Alexandre M; Tranter, Martyn; Fountain, Andrew G; Nylen, Thomas; Hawkings, Jon; Singh, Virendra B; Kaur, Preeti; Musilova, Michaela; Wadham, Jemma L

2014-01-01

The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw toward fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus) with longer isolation age. During the initial melt there was a mean nine times enrichment in dissolved chloride relative to mean concentrations of the initial frozen holes indicative of an ionic pulse, with similar mean nine times enrichments in nitrite, ammonium, and dissolved organic matter. Nitrate was enriched twelve times and dissolved organic nitrogen six times, suggesting net nitrification, while lower enrichments for dissolved organic phosphorus and phosphate were consistent with net microbial phosphorus uptake. Rates of bacterial production were significantly elevated during the ionic pulse, likely due to the increased nutrient availability. There was no concomitant increase in photosynthesis rates, with a net depletion of dissolved inorganic carbon suggesting inorganic carbon limitation. Potential nitrogen fixation was detected in fully melted holes where it could be an important source of nitrogen to support microbial growth, but not during the ionic pulse where nitrogen availability was higher. This study demonstrates that ionic pulses significantly alter the timing and magnitude of microbial activity within entombed cryoconite holes, and adds credence to hypotheses that ionic enrichments during freeze-thaw can elevate rates of microbial growth and activity in other icy habitats, such as ice veins and subglacial regelation zones.

Nutrient cycling and ecosystem metabolism in boreal streams of the Central Siberian Plateau

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Diemer, L.; McDowell, W. H.; Prokushkin, A. S.

2013-12-01

Arctic boreal streams are undergoing considerable change in carbon and nutrient biogeochemistry due to degrading permafrost and increasing fire activity. Recent studies show that fire increases transport of inorganic solutes from the boreal landscape to arctic streams in some regions; couple this with expected greater labile dissolved organic carbon (DOC) from deepening active layers, enhanced biomass production, and increased annual precipitation and boreal streams may experience greater in-stream primary production and respiration in the coming century. Little is known about the spatial and temporal dynamics of inorganic nutrients in relation to C availability in headwater streams of a major Arctic region, the Central Siberian Plateau. Our preliminary data of Central Siberian headwater streams show NO3 and PO4 concentrations near or below detection limits (e.g. nine samples taken in spring from a small stream near the Russian settlement of Tura averaged 10 μg/L NO3-N and 9.7 μg/L PO4-P), and recent studies in Central Siberia suggest that bioavailable organic matter and inorganic nutrients such as NO3 will likely increase with climate warming. We examined the fate of nutrients in Central Siberian streams using Tracer for Spiraling Curve Characterization (TASCC) additions of NO3, NH4, and PO4 along with conservative tracer, NaCl, in spring at high and low discharges in streams underlain by continuous permafrost in Central Siberia. We also sampled two sites in spring every 2 hours overnight for 24 hours to document any diel patterns in DOC and inorganic nutrients. Our results thus far show that NO3 uptake length may be strongly correlated with DOC concentration (a function of fire activity). Preliminary results also show that despite high discharge and cold temperatures (4-8°C) in mid to late spring, there appears to be biological activity stimulating a diel signal for NO3 with maximum concentration corresponding to low light (11 PM). Investigating the primary

Spatial Heterogeneity of Soil Nutrients after the Establishment of Caragana intermedia Plantation on Sand Dunes in Alpine Sandy Land of the Tibet Plateau.

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Li, Qingxue; Jia, Zhiqing; Zhu, Yajuan; Wang, Yongsheng; Li, Hong; Yang, Defu; Zhao, Xuebin

2015-01-01

The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil "fertile islands" were formed, and the "fertile islands" were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous shrub.

Nutrient supply of plants in aquaponic systems

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Andras Bittsanszky

2016-10-01

Full Text Available In this preliminary article we present data on plant nutrient concentrations in aquaponics systems, and we compare them to nutrient concentrations in “standard” hydroponic solutions. Our data shows that the nutrient concentrations supplied by the fish in the aquaponics system are significantly lower for most nutrients compared to hydroponic systems. Nevertheless, plants do thrive in solutions that have lower nutrient levels compared to “standard” hydroponic solutions. This is especially true for green leafy vegetables that rarely need additional nutritional supplementation. It is concluded that in the highly complex system of aquaponics, special care has to be taken, via continuous monitoring of the chemical composition of the circulating water, to provide adequate concentrations and ratios of nutrients, and especially for the potentially toxic component, ammonium. If certain plants require nutrient supplementation, we consider that one based on organic substances would be most beneficial. However, protocols for the application of such nutrient amendments still need to be developed.

Continental-scale effects of nutrient pollution on stream ecosystem functioning.

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Woodward, Guy; Gessner, Mark O; Giller, Paul S; Gulis, Vladislav; Hladyz, Sally; Lecerf, Antoine; Malmqvist, Björn; McKie, Brendan G; Tiegs, Scott D; Cariss, Helen; Dobson, Mike; Elosegi, Arturo; Ferreira, Verónica; Graça, Manuel A S; Fleituch, Tadeusz; Lacoursière, Jean O; Nistorescu, Marius; Pozo, Jesús; Risnoveanu, Geta; Schindler, Markus; Vadineanu, Angheluta; Vought, Lena B-M; Chauvet, Eric

2012-06-15

Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.

Vermicomposting of herbal pharmaceutical industry waste: earthworm growth, plant-available nutrient and microbial quality of end materials.

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Singh, Deepika; Suthar, Surindra

2012-05-01

Efforts were made to decompose herbal pharmaceutical industrial waste (HPIW) spiked with cow dung (CD) using Eisenia fetida. A total of five vermibeds: T(1) - HPIW (0%+CD 100%, control), T(2) - HPIW (25%), T(3) - HPIW (50%), T(4) - HPIW (75%) and T(5) - HPIW (100%) were used for vermicomposting. The changes in biology and chemistry of vermibeds were measured after ten days interval. E. fetida showed high growth and cocoon production rate in all vermibeds. The vermicomposted material contained great population of fungi 6.0-40.6 (CFU × 10(5)g(-1)), bacteria 220-1276.0 (CFU × 10(8)g(-1)) and actinomycetes 410.0-2962.0 (CFU × 10(5)g(-1)) than initial material. Vermicomposted material was rich in plant-available forms of nutrients (N-NO(3)(-),PO(4)(3-),available K and SO(4)(-2)). Results suggested that noxious industrial waste can be converted into valuable product for sustainable soil fertility programme. Copyright © 2012 Elsevier Ltd. All rights reserved.

Improving Lowland Rice (O. sativa L. cv. MR219 Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Crude Humic Substances

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Perumal Palanivell

2015-01-01

Full Text Available High cation exchange capacity and organic matter content of crude humic substances from compost could be exploited to reduce ammonia loss from urea and to as well improve rice growth and soil chemical properties for efficient nutrients utilization in lowland rice cultivation. Close-dynamic air flow system was used to determine the effects of crude humic substances on ammonia volatilization. A pot experiment was conducted to determine the effects of crude humic substances on rice plant growth, nutrients uptake, nutrients recovery, and soil chemical properties using an acid soil mixed with three rates of crude humic substances (20, 40, and 60 g pot−1. Standard procedures were used to evaluate rice plant dry matter production, nutrients uptake, nutrients recovery, and soil chemical properties. Application of crude humic substances increased ammonia volatilization. However, the lowest rate of crude humic substances (20 g pot−1 significantly improved total dry matter, nutrients uptake, nutrients recovery, and soil nutrients availability compared with crude humic substances (40 and 60 g pot−1 and the normal fertilization. Apart from improving growth of rice plants, crude humic substances can be used to ameliorate acid soils in rice cultivation. The findings of this study are being validated in our ongoing field trials.

The quality of our Nation's waters-Nutrients in the Nation's streams and groundwater, 1992-2004

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Dubrovsky, N.M.; Burow, K.R.; Clark, G.M.; Gronberg, J.M.; Hamilton, P.A.; Hitt, K.J.; Mueller, D.K.; Munn, M.D.; Nolan, B.T.; Puckett, L.J.; Rupert, M.G.; Short, T.M.; Spahr, N.E.; Sprague, L.A.; Wilber, W.G.

2010-01-01

National Findings and Their Implications Although the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatic life, often by large margins. Do NAWQA findings substantiate national concerns for aquatic and human health? National Water-Quality Assessment (NAWQA) findings indicate that nutrient concentrations in streams and groundwater in basins with significant agricultural or urban development are substantially greater than naturally occurring or ?background? levels. For example, median concentrations of total nitrogen and phosphorus in agricultural streams are about 6 times greater than background levels. Findings also indicate that concentrations in streams routinely were 2 to 10 times greater than regional nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic life. Such large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, are needed to meet recommended criteria for streams draining areas with significant agricultural and urban development. Nitrate concentrations above the Federal drinking-water standard-or Maximum Contaminant Level (MCL)-of 10 milligrams per liter (mg/L, as nit-ogen) are relatively uncommon in samples from streams used for drinking water or from relatively deep aquifers; the MCL is exceeded, however, in more than 20 percent of shallow (less than 100 feet below the water table) domestic wells in agricultural areas. This finding raises concerns for human health in rural agricultural areas where shallow groundwater is used for domestic supply and may warn of future

Soil nutrient availability and its impact on fruit quality of Tahiti acid lime Disponibilidade de nutrientes no solo e impactos na qualidade de frutos da lima-ácida Tahiti

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Dirceu Mattos Junior

2010-03-01

Full Text Available The Tahiti acid lime in Brazil is mostly grown in the São Paulo State. The value of this crop production ranks among the ten most important fruits in the country. The Brazilian exports of Tahiti limes have increased in the last years with a corresponding increased demand for superior quality of fresh fruits, which is affected by mineral nutrients. Therefore, this study evaluated nutrient soil availability and its influence on nutritional status of trees based on the determination of leaf and fruit nutrient concentrations, fruit characteristics, and post harvest quality. Eleven commercial groves with trees older than 4-yr and differently managed were studied. Plots with six trees in each grove were sampled for soil (0-20 cm depth layer, leaf and fruit analyses with three replicates. Correlation coefficients were pair wised established for all variables. The results showed that N leaf concentration was well correlated with green color of fruit peel as measured by a color index (r = -0.71**, and which was optimum with Leaf-N around 22 g kg-1. Leaf-Ca was inversely correlated with fruit water loss after 14-day interval from harvest (r = -0.54* demonstrating that Ca plays an important role in Tahiti fruit shelf-life. Data also suggested that increased fruit K concentration correlated with increased fruit water losses during storage (r >0.58*.No Brasil, a lima-ácida Tahiti é produzida principalmente em São Paulo. O valor dessa produção situa-se entre as dez variedades de frutas mais importantes no País. As exportações brasileiras de Tahiti in natura aumentaram significativamente nos últimos anos e têm demandado frutas de qualidade superior. Essas características são afetadas pelos nutrientes minerais. Assim, o trabalho avaliou os efeitos da disponibilidade de nutrientes no solo, sua influência no estado nutricional das plantas e no teor desses nos frutos, e correlações sobre a qualidade de Tahiti, como maneira de criar subsídios para

Fungi benefit from two decades of increased nutrient availability in tundra heath soil.

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Rinnan, Riikka; Michelsen, Anders; Bååth, Erland

2013-01-01

If microbial degradation of carbon substrates in arctic soil is stimulated by climatic warming, this would be a significant positive feedback on global change. With data from a climate change experiment in Northern Sweden we show that warming and enhanced soil nutrient availability, which is a predicted long-term consequence of climatic warming and mimicked by fertilization, both increase soil microbial biomass. However, while fertilization increased the relative abundance of fungi, warming caused only a minimal shift in the microbial community composition based on the phospholipid fatty acid (PLFA) and neutral lipid fatty acid (NLFA) profiles. The function of the microbial community was also differently affected, as indicated by stable isotope probing of PLFA and NLFA. We demonstrate that two decades of fertilization have favored fungi relative to bacteria, and increased the turnover of complex organic compounds such as vanillin, while warming has had no such effects. Furthermore, the NLFA-to-PLFA ratio for (13)C-incorporation from acetate increased in warmed plots but not in fertilized ones. Thus, fertilization cannot be used as a proxy for effects on warming in arctic tundra soils. Furthermore, the different functional responses suggest that the biomass increase found in both fertilized and warmed plots was mediated via different mechanisms.

Yield Gap, Indigenous Nutrient Supply and Nutrient Use Efficiency for Maize in China.

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Xinpeng Xu

Full Text Available Great achievements have been attained in agricultural production of China, while there are still many difficulties and challenges ahead that call for put more efforts to overcome to guarantee food security and protect environment simultaneously. Analyzing yield gap and nutrient use efficiency will help develop and inform agricultural policies and strategies to increase grain yield. On-farm datasets from 2001 to 2012 with 1,971 field experiments for maize (Zea mays L. were collected in four maize agro-ecological regions of China, and the optimal management (OPT, farmers' practice (FP, a series of nutrient omission treatments were used to analyze yield gap, nutrient use efficiency and indigenous nutrient supply by adopting meta-analysis and ANOVA analysis. Across all sites, the average yield gap between OPT and FP was 0.7 t ha-1, the yield response to nitrogen (N, phosphorus (P, and potassium (K were 1.8, 1.0, and 1.2 t ha-1, respectively. The soil indigenous nutrient supply of N, P, and K averaged 139.9, 33.7, and 127.5 kg ha-1, respectively. As compared to FP, the average recovery efficiency (RE of N, P, and K with OPT increased by percentage point of 12.2, 5.5, and 6.5, respectively. This study indicated that there would be considerable potential to further improve yield and nutrient use efficiency in China, and will help develop and inform agricultural policies and strategies, while some management measures such as soil, plant and nutrient are necessary and integrate with advanced knowledge and technologies.

Nutrient critical levels and availability in soils cultivated with peach palm (Bactris gasipaes Kunth. in Santo Domingo de Los Tsáchilas, Ecuador

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Carlos Julio Quezada Crespo

2017-04-01

Full Text Available Ecuador is the most important exporter of canned peach palm, however, to date ideal soil fertility characteristics for peach palm growers remain unknown. The aim of this research was to determine optimal levels of soil nutrients for the cultivation of peach palm, specifically with regards to soil cation exchange capacity in order to obtain higher yields. We worked with 20 farmsteads and their soils from the province of Santo Domingo de los Tsáchilas during the second half of 2014. Fields were evaluated based on a relative yield and extractable (modified Olsen nutrient contents in each soil were determined using regression modeling to determine critical levels of each nutrient and specifically to determine the ideal soil cation exchange capacity under peach palm cultivation. Our analysis established critical levels of soil pH (6.3; OM 6.5%; P 12.3 mg.dm-3; K 0.67 cmol.dm-3 K; Ca 5.1 cmol.dm-3 ; Mg 0.97 cmol.dm-3; and S 7.5 mg.dm-3. The ideal Ca: Mg: K soil cation exchange capacity was determined to be 76:14:10.

Nutritional analysis and microbiological evaluation of commercially available enteral diets for cats.

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Prantil, Lori R; Markovich, Jessica E; Heinze, Cailin R; Linder, Deborah E; Tams, Todd R; Freeman, Lisa M

2016-01-01

To determine the prevalence of nutrients less than or greater than accepted standards in commercially available enteral diets for cats, and to identify contamination incidence in enteral diets for cats. Prospective cross-sectional study. University teaching hospital. Seven commercial enteral diets for cats. Labels were evaluated to determine if diets were intended to be nutritionally complete and balanced. One diet under storage techniques partially representative of clinical conditions was sampled on days 0, 1, 3, 5, and 7 of storage for aerobic bacterial culture. All 7 diets were analyzed for key nutrients and results were compared to Association of American Feed Control Officials (AAFCO) Nutrient Profiles for Adult Cats for maintenance and National Research Council recommended allowance (NRC-RA). From label information, 4 diets were classified as complete and balanced and 3 diets were classified as not complete and balanced. All 7 diets had at least 1 nutrient less than the AAFCO minimums and the NRC-RA. The total number of nutrients less than AAFCO minimums ranged from 3 to 9 (median = 4), with iron, potassium, and manganese being the most common. Concentrations of some nutrients were undetectable. None of the samples tested had a positive aerobic culture at baseline (day 0) or on subsequent samples from days 1, 3, 5, and 7 under any storage condition. None of the diets analyzed met all of the minimum nutrient concentrations. While short-term feeding may not be of concern for an individual patient, clinicians should be aware of potential nutritional limitations when feeding enteral diets to ill or injured cats. © Veterinary Emergency and Critical Care Society 2015.

TOR Signaling and Nutrient Sensing.

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Dobrenel, Thomas; Caldana, Camila; Hanson, Johannes; Robaglia, Christophe; Vincentz, Michel; Veit, Bruce; Meyer, Christian

2016-04-29

All living organisms rely on nutrients to sustain cell metabolism and energy production, which in turn need to be adjusted based on available resources. The evolutionarily conserved target of rapamycin (TOR) protein kinase is a central regulatory hub that connects environmental information about the quantity and quality of nutrients to developmental and metabolic processes in order to maintain cellular homeostasis. TOR is activated by both nitrogen and carbon metabolites and promotes energy-consuming processes such as cell division, mRNA translation, and anabolism in times of abundance while repressing nutrient remobilization through autophagy. In animals and yeasts, TOR acts antagonistically to the starvation-induced AMP-activated kinase (AMPK)/sucrose nonfermenting 1 (Snf1) kinase, called Snf1-related kinase 1 (SnRK1) in plants. This review summarizes the immense knowledge on the relationship between TOR signaling and nutrients in nonphotosynthetic organisms and presents recent findings in plants that illuminate the crucial role of this pathway in conveying nutrient-derived signals and regulating many aspects of metabolism and growth.

Source Material and Concentration of Wildfire-Produced Pyrogenic Carbon Influence Post-Fire Soil Nutrient Dynamics

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Lucas A. Michelotti

2015-04-01

Full Text Available Pyrogenic carbon (PyC is produced by the thermal decomposition of organic matter in the absence of oxygen (O. PyC affects nutrient availability, may enhance post-fire nitrogen (N mineralization rates, and can be a significant carbon (C pool in fire-prone ecosystems. Our objectives were to characterize PyC produced by wildfires and examine the influence that contrasting types of PyC have on C and N mineralization rates. We determined C, N, O, and hydrogen (H concentrations and atomic ratios of charred bark (BK, charred pine cones (PC, and charred woody debris (WD using elemental analysis. We also incubated soil amended with BK, PC, and WD at two concentrations for 60 days to measure C and N mineralization rates. PC had greater H/C and O/C ratios than BK and WD, suggesting that PC may have a lesser aromatic component than BK and WD. C and N mineralization rates decreased with increasing PyC concentrations, and control samples produced more CO2 than soils amended with PyC. Soils with PC produced greater CO2 and had lower N mineralization rates than soils with BK or WD. These results demonstrate that PyC type and concentration have potential to impact nutrient dynamics and C flux to the atmosphere in post-fire forest soils.

Plants may alter competition by modifying nutrient bioavailability in rhizosphere: a modeling approach.

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Raynaud, Xavier; Jaillard, Benoît; Leadley, Paul W

2008-01-01

Plants modify nutrient availability by releasing chemicals in the rhizosphere. This change in availability induced by roots (bioavailability) is known to improve nutrient uptake by individual plants releasing such compounds. Can this bioavailability alter plant competition for nutrients and under what conditions? To address these questions, we have developed a model of nutrient competition between plant species based on mechanistic descriptions of nutrient diffusion, plant exudation, and plant uptake. The model was parameterized using data of the effects of root citrate exudation on phosphorus availability. We performed a sensitivity analysis for key parameters to test the generality of these effects. Our simulations suggest the following. (1) Nutrient uptake depends on the number of roots when nutrients and exudates diffuse little, because individual roots are nearly independent in terms of nutrient supply. In this case, bioavailability profits only species with exudates. (2) Competition for nutrients depends on the spatial arrangement of roots when nutrients diffuse little but exudates diffuse widely. (3) Competition for nutrients depends on the nutrient uptake capacity of roots when nutrients and exudates diffuse widely. In this case, bioavailability profits all species. Mechanisms controlling competition for bioavailable nutrients appear to be diverse and strongly depend on soil, nutrient, and plant properties.

Can nutrient limitations explain low and declining white spruce growth near the Arctic treeline in the eastern Brooks Range, Alaska?

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Ellison, S.; Sullivan, P. F.

2014-12-01

The position of the Arctic treeline is of critical importance for global carbon cycling and surface energy budgets. However, controls on tree growth at treeline remain uncertain. In the Alaskan Brooks Range, 20th century warming has caused varying growth responses among treeline trees, with trees in the west responding positively, while trees in the east have responded negatively. The prevailing explanation of this trend ascribes the negative growth response to warming-induced drought stress in the eastern Brooks Range. However, recent measurements of carbon isotope discrimination in tree rings, xylem sap flow and needle gas exchange suggest that drought stress cannot explain these regional growth declines. Additionally, evidence from the western Brooks Range suggests that nutrient availability, rather than drought stress, may be the proximate control on tree growth. In this study, we investigated the hypothesis that low and declining growth of eastern Brooks Range trees is due to low and declining soil nutrient availability, which may continue to decrease with climate change as soils become drier and microbial activity declines. We compared microclimate, tree performance, and a wide range of proxies for soil nutrient availability in four watersheds along a west-east transect in the Brooks Range during the growing seasons of 2013 and 2014. We hypothesized that soil nutrient availability would track closely with the strong west-east precipitation gradient, with higher rainfall and greater soil nutrient availability in the western Brooks Range. We expected to find that soil water contents in the west are near optimum for nitrogen mineralization, while those in the east are below optimum. Needle nitrogen concentration, net photosynthesis, branch extension growth, and growth in the main stem are expected to decline with the hypothesized decrease in soil nutrient availability. The results of our study will elucidate the current controls on growth of trees near the

Context-dependent effects of nutrient loading on the coral-algal mutualism.

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Shantz, Andrew A; Burkepile, Deron E

2014-07-01

Human-mediated increases in nutrient availability alter patterns of primary production, impact species diversity, and threaten ecosystem function. Nutrients can also alter community structure by disrupting the relationships between nutrient-sharing mutualists that form the foundation of communities. Given their oligotrophic nature and the dependence of reef-building corals on symbiotic relationships, coral reefs may be particularly vulnerable to excess nutrients. However, individual studies suggest complex, even contradictory, relationships among nutrient availability, coral physiology, and coral growth. Here, we used meta-analysis to establish general patterns of the impact of nitrogen (N) and phosphorus (P) on coral growth and photobiology. Overall, we found that over a wide range of concentrations, N reduced coral calcification 11%, on average, but enhanced metrics of coral photobiology, such as photosynthetic rate. In contrast, P enrichment increased average calcification rates by 9%, likely through direct impacts on the calcification process, but minimally impacted coral photobiology. There were few synergistic impacts of combined N and P on corals, as the nutrients impact corals via different pathways. Additionally, the response of corals to increasing nutrient availability was context dependent, varying with coral taxa and morphology, enrichment source, and nutrient identity. For example, naturally occurring enrichment from fish excretion increased coral growth, while human-mediated enrichment tended to decrease coral growth. Understanding the nuances of the relationship between nutrients and corals may allow for more targeted remediation strategies and suggest how other global change drivers such as overfishing and climate change will shape how nutrient availability impacts corals.

Effects of light quality and nutrient availability on accumulation of mycosporine-like amino acids in Gymnodinium catenatum (Dinophycea).

Science.gov (United States)

Vale, Paulo

2015-02-01

A Portuguese Gymnodinium catenatum Graham strain was studied for its ultraviolet (UV) photoprotective pigments. This strain presented high absorption in the UVA region, in particular in the near UVA region around 370nm, followed by the far-UVA region around 340nm. Absorption in the near-UVA increased when grown under fluorescent when compared to halogen light. This was even more relevant when grown under nutrient-limiting conditions, which even surpassed absorption in the blue region, closely resembling absorption in natural plankton assemblages reported in the literature. HPLC analysis for mycosporine-like amino acids (MAAs), revealed several UV photoprotective pigments common in other marine microalgae from the northwest Atlantic. Amongst the compounds absorbing in the far-UVA region, three were identified by spectra and retention time characteristics: shinorine, porphyra-334, and mycosporine-glycine. In the near-UVA region, the unknown M-370 was usually the most abundant, followed by palythene. The proportional and absolute cellular concentrations of MAAs absorbing in the near-UVA region increased with fluorescent light when compared to halogen light. Additional experiments with light filtration suggest the set of MAAs absorbing in the near-UVA region seem to be regulated separately from the other set of MAAs absorbing in the far-UVA region, and those from the near-UVA region might be stimulated not only by UV but by blue light also. Nutrient availability affected profile: a shift towards MAAs with low nitrogen:carbon ratio (e.g.: mycosporine-glycine) was observed. As G. catenatum requires extensive UV-photoprotection over the entire UVA range, nitrogen availability might strongly restrict blooming, as MAAs are nitrogen-based. This UV sensitivity might help explaining its pronounced autumnal seasonality, tied to a reduced solar exposure. Copyright © 2014 Elsevier B.V. All rights reserved.

WERF Nutrient Challenge investigates limits of nutrient removal technologies.

Science.gov (United States)

Neethling, J B; Clark, D; Pramanik, A; Stensel, H D; Sandino, J; Tsuchihashi, R

2010-01-01

The WERF Nutrient Challenge is a multi-year collaborative research initiative established in 2007 to develop and provide current information about wastewater treatment nutrients (specifically nitrogen and phosphorus in wastewater), their characteristics, and bioavailability in aquatic environments to help regulators make informed decisions. The Nutrient Challenge will also provide data on nutrient removal so that treatment facilities can select sustainable, cost-effective methods and technologies to meet permit limits. To meet these goals, the Nutrient Challenge has teamed with a wide array of utilities, agencies, consultants, universities and other researchers and practitioners to collaborate on projects that advance these goals. The Nutrient Challenge is focusing on a different approach to collaborating and leveraging resources (financial and intellectual) on research projects by targeting existing projects and research that correspond with its goals and funding those aspects that the Nutrient Challenge identified as a priority. Because the Nutrient Challenge is focused on collaboration, outreach is an absolutely necessary component of its effectiveness. Through workshops, webinars, a web portal and online compendium, published papers, and conference lectures, the Nutrient Challenge is both presenting important new information, and soliciting new partnerships.

The subtropical nutrient spiral

Science.gov (United States)

Jenkins, William J.; Doney, Scott C.

2003-12-01

We present an extended series of observations and more comprehensive analysis of a tracer-based measure of new production in the Sargasso Sea near Bermuda using the 3He flux gauge technique. The estimated annually averaged nitrate flux of 0.84 ± 0.26 mol m-2 yr-1 constitutes only that nitrate physically transported to the euphotic zone, not nitrogen from biological sources (e.g., nitrogen fixation or zooplankton migration). We show that the flux estimate is quantitatively consistent with other observations, including decade timescale evolution of the 3H + 3He inventory in the main thermocline and export production estimates. However, we argue that the flux cannot be supplied in the long term by local diapycnal or isopycnal processes. These considerations lead us to propose a three-dimensional pathway whereby nutrients remineralized within the main thermocline are returned to the seasonally accessible layers within the subtropical gyre. We describe this mechanism, which we call "the nutrient spiral," as a sequence of steps where (1) nutrient-rich thermocline waters are entrained into the Gulf Stream, (2) enhanced diapycnal mixing moves nutrients upward onto lighter densities, (3) detrainment and enhanced isopycnal mixing injects these waters into the seasonally accessible layer of the gyre recirculation region, and (4) the nutrients become available to biota via eddy heaving and wintertime convection. The spiral is closed when nutrients are utilized, exported, and then remineralized within the thermocline. We present evidence regarding the characteristics of the spiral and discuss some implications of its operation within the biogeochemical cycle of the subtropical ocean.

Mass-Balance Constraints on Nutrient Cycling in Tropical Seagrass Beds

NARCIS (Netherlands)

Erftemeijer, P.L.A.; Middelburg, J.J.

1995-01-01

A relatively simple mass balance model is presented to study the cycling of nutrients (nitrogen and phosphorus) in tropical seagrass beds. The model is based on quantitative data on nutrient availability, seagrass primary production, community oxygen metabolism, seagrass tissue nutrient contents,

Water and nutrient budgets for Vancouver Lake, Vancouver, Washington, October 2010-October 2012

Science.gov (United States)

Sheibley, Rich W.; Foreman, James R.; Marshall, Cameron A.; Welch, Wendy B.

2014-01-01

Vancouver Lake, a large shallow lake in Clark County, near Vancouver, Washington, has been undergoing water-quality problems for decades. Recently, the biggest concern for the lake are the almost annual harmful cyanobacteria blooms that cause the lake to close for recreation for several weeks each summer. Despite decades of interest in improving the water quality of the lake, fundamental information on the timing and amount of water and nutrients entering and exiting the lake is lacking. In 2010, the U.S. Geological Survey conducted a 2-year field study to quantify water flows and nutrient loads in order to develop water and nutrient budgets for the lake. This report presents monthly and annual water and nutrient budgets from October 2010–October 2012 to identify major sources and sinks of nutrients. Lake River, a tidally influenced tributary to the lake, flows into and out of the lake almost daily and composed the greatest proportion of both the water and nutrient budgets for the lake, often at orders of magnitude greater than any other source. From the water budget, we identified precipitation, evaporation and groundwater inflow as minor components of the lake hydrologic cycle, each contributing 1 percent or less to the total water budget. Nutrient budgets were compiled monthly and annually for total nitrogen, total phosphorus, and orthophosphate; and, nitrogen loads were generally an order of magnitude greater than phosphorus loads across all sources. For total nitrogen, flow from Lake River at Felida, Washington, made up 88 percent of all inputs into the lake. For total phosphorus and orthophosphate, Lake River at Felida flowing into the lake was 91 and 76 percent of total inputs, respectively. Nutrient loads from precipitation and groundwater inflow were 1 percent or less of the total budgets. Nutrient inputs from Burnt Bridge Creek and Flushing Channel composed 12 percent of the total nitrogen budget, 8 percent of the total phosphorus budget, and 21 percent

Influence of snow cover distribution on soil temperature and nutrient dynamics in alpine pedoenvironments

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Ermanno Zanini

Full Text Available In Alpine sites snow is present on the ground from six to eight months per year in relation to elevation and exposure. Water is therefore immobilized into the solid state for the greater part of the winter season and released to the ground in a short period during spring snowmelt. In these areas, snow distribution exercises a fundamental role in influencing soil temperature and nutrient dynamics, in particular of nitrogen, with great consequences on plant nutrition. The dormant vegetation period, the low temperatures and the persistent snow cover suggest that soil biological activity is only concentrated during summer. As a matter of fact, soils covered with a consistent snow cover are isolated from the air temperature and can not freeze during winter. A snowpack of sufficient thickness, accumulated early in winter, insulates the ground from the surrounding atmosphere maintaining soil temperature closed to 0 °C during the whole winter season. The elevation of the snow line and the shorter permanence of snow on the ground, as a result of global warming (IPCC, 1996, 2001, might reduce the insulation effect of the snowpack, exposing soils of the mountain belt to lower temperatures and to a greater frequency of freeze/thaw cycles, which might alter organic matter dynamics and soil nutrient availability. Such thermal stresses may determine the lysis of microbial cells and the consequent increase of nitrogen and carbon mineralization by the survived microorganisms. Moreover, the freeze/thaw cycles can determine the exposure of exchange surfaces not available before, with release of organic matter of non-microbial origin, which may become available to surviving microorganisms for respiration. The reduced or absent microbial immobilization may cause the accumulation of remarkable amounts of inorganic nitrogen in soil, potentially leachable during spring snowmelt, when plants have not still started the growing season. Changes of snow distribution in

Invasiveness of Cut-Leaf Ground-Cherry (Physalis angulata L. Populations and Impact of Soil Water and Nutrient Availability Potencial Invasor de Poblaciones de Tomatillos de Brihuega (Physalis angulata L. e Impacto del Contenido de Agua y Disponibilidad de Nutrientes del Suelo

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Ilias S Travlos

2012-09-01

Full Text Available Biological invasions are a major threat to natural ecosystems and agroecosystems, while weed flora is noticeably changing globally. In this study we evaluated the potential of cut-leaf ground-cherry (Physalis angulata L., a species native to America, to invade the semi-arid regions of Greece. Greenhouse and laboratory experiments were conducted to evaluate the effects of different environmental resources (nutrient and water availability on seedling growth, biomass production, fecundity, and seed germination of four populations of cut-leaf ground-cherry. Our results suggest that cut-leaf ground-cherry does not tolerate extreme drought during the first growth stages, while it can survive and produce adequate and rapidly germinated seed (> 85% under low soil moisture conditions. Moreover, high water and nutrient availability results in high growth and biomass production and ensures high seed production, reaching more than 4000 seeds plant-1. We suggest that soil water content and nutrient availability are the two critical factors affecting the invasive potential of cut-leaf ground-cherry in semi-arid environments. Understanding the plant's ecological features through a study conducted at an early stage rather than a late stage of invasion will help us to take appropriate control measures for this species, which should primarily target frequently fertilized fields after precipitation events.Las invasiones biológicas son una amenaza importante para los ecosistemas naturales y agroecosistemas, mientras que, globalmente, la flora de malezas parece cambiar notablemente. En este estudio se evaluó el potencial de una especie nativa de América, tomatillos de Brihuega (Physalis angulata L., para invadir las regiones semiáridas de Grecia. Se realizaron experimentos de invernadero y laboratorio para evaluar los efectos de diferentes recursos ambientales (disponibilidad de nutrientes y agua, crecimiento de las plántulas, producción de biomasa, fecundidad

Global Expanded Nutrient Supply (GENuS Model: A New Method for Estimating the Global Dietary Supply of Nutrients.

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Matthew R Smith

Full Text Available Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1 data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2 household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model--the Global Expanded Nutrient Supply (GENuS model--to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against

Characterization of nutrient deficiency in Hancornia speciosa Gomes seedlings by omitting micronutrients from the nutrient solution

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Layara Alexandre Bessa

2013-06-01

Full Text Available Hancornia speciosa Gomes (Mangaba tree is a fruit tree belonging to the Apocynaceae family and is native to Brazil. The production of seedlings of this species is limited by a lack of technical and nutritional expertise. To address this deficiency, this study aimed to characterize the visual symptoms of micronutrient deficiency and to assess growth and leaf nutrient accumulation in H. speciosa seedlings supplied with nutrient solutions that lack individual micronutrients. H. speciosa plants were grown in nutrient solution in a greenhouse according to a randomized block design, with four replicates. The treatments consisted of a group receiving complete nutrient solution and groups treated with a nutrient solution lacking one of the following micronutrients: boron (B, copper (Cu, iron (Fe, manganese (Mn, zinc (Zn, and molybdenum (Mo. The visual symptoms of nutrient deficiency were generally easy to characterize. Dry matter production was affected by the omission of micronutrients, and the treatment lacking Fe most limited the stem length, stem diameter, root length, and number of leaves in H. speciosa seedlings as well as the dry weight of leaves, the total dry weight, and the relative growth in H. speciosa plants. The micronutrient contents of H. speciosa leaves from plants receiving the complete nutrient solution treatment were, in decreasing order, Fe>Mn>Cu>Zn>B.

Maternal–Fetal Nutrient Transport in Pregnancy Pathologies: The Role of the Placenta

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Kendra Elizabeth Brett

2014-09-01

Full Text Available Appropriate in utero growth is essential for offspring development and is a critical contributor to long-term health. Fetal growth is largely dictated by the availability of nutrients in maternal circulation and the ability of these nutrients to be transported into fetal circulation via the placenta. Substrate flux across placental gradients is dependent on the accessibility and activity of nutrient-specific transporters. Changes in the expression and activity of these transporters is implicated in cases of restricted and excessive fetal growth, and may represent a control mechanism by which fetal growth rate attempts to match availability of nutrients in maternal circulation. This review provides an overview of placenta nutrient transport with an emphasis on macro-nutrient transporters. It highlights the changes in expression and activity of these transporters associated with common pregnancy pathologies, including intrauterine growth restriction, macrosomia, diabetes and obesity, as well as the potential impact of maternal diet. Molecular signaling pathways linking maternal nutrient availability and placenta nutrient transport are discussed. How sexual dimorphism affects fetal growth strategies and the placenta’s response to an altered intrauterine environment is considered. Further knowledge in this area may be the first step in the development of targeted interventions to help optimize fetal growth.

Nutrient Availability and Changes on Chemical Attributes of a Paleudult Soil Amended with Liquid Sewage Sludge and Cropped with Surinam Grass

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Luiz Carlos Ceolato

2011-01-01

Full Text Available The liquid sewage sludge (LSS was applied on a field experiment during four years at successive applications to evaluate the changes in soil attributes and on Surinam grass (Brachiaria decumbens uptake of nutrients. A randomized blocks experimental design, with two treatments (with and without LSS and three repetitions, was used. Land application of LSS did not alter soil organic matter and exchangeable K until 40 cm depth. However, it increased soil pH, base saturation, labile P, and available Zn and did not change the concentrations of available B (hot water and Cu, Fe, and Mn (DTPA at 0–20 cm and 20–40 cm depths and LSS was a source of N, K, P, Ca, Mg, and Zn for the grass, but decreased leaf Mn concentration.

Contribution of trees and grasses to ecosystem fluxes of water, carbon, and energy throughout the seasons under different nutrient availability

Science.gov (United States)

El-Madany, T. S.; Migliavacca, M.; Perez-Priego, O.; Luo, Y.; Moreno, G.; Carrara, A.; Kolle, O.; Reichstein, M.

2017-12-01

In semi-arid savanna type ecosystems, the carbon and water cycle are closely related to each other. Water availability is the main driver for the development and phenology of the vegetation, especially for annual plants. Depending on tree density, nutrient availability and species the contribution of the tree- and the herbaceous layer to ecosystem fluxes can vary substantially. We present data from an ecosystem scale nutrient manipulation experiment within a Mediterranean savanna type ecosystem which is used for cattle. The footprint areas of two out of three ecosystem eddy co-variance (EC) towers were fertilized with nitrogen (NT) and nitrogen plus phosphorous (NPT) while the third one served as the control tower (CT). At each ecosystem EC-tower an additional herbaceous layer tower was installed that only sampled fluxes from the herbaceous layer. Under certain assumptions flux differences between the ecosystem EC and the herbaceous layer EC systems can be considered as the contribution of the trees to the ecosystem fluxes. Based on phenology of the herbaceous layer estimated through green-chromatic-coordinates from digital imagery the year was separated into spring, senescence, regreening, and winter. The focus of the analysis is (i) the evaluation of the method and how it works throughout the different seasons and (ii) the quantification of the contribution of trees and grasses to ecosystem fluxes of water, carbon, and energy under different environmental conditions and nutrient stoichiometry. The contribution of the trees to total ecosystem fluxes is variable in time. Especially, during the beginning of the senescence period high evapotranspiration rates and largest carbon uptake are measured while the contribution to sensible heat fluxes is largest during the end of the summer. During the regreening and winter the contribution of ET is relatively constant around 0.25 mm d-1. During the peak of the greenness ET and carbon flux of the herbaceous EC tower are

Lignocellulose mineralization by Arctic lake sediments in response to nutrient manipulation

International Nuclear Information System (INIS)

Federle, T.W.; Vestal, J.R.

1980-01-01

Mineralization of specifically labeled 14 C-cellulose- and 14 C-lignin-labeled lignocelluloses by Toolik Lake, Alaska, sediments was examined in response to manipulation of various environmental factors. Mineralization was measured by quantifying the amount of labeled CO 2 released from the specifically labeled substrates. Nitrogen (NH 4 NO 3 ) and, to a greater degree, phosphorus (PO 4 -3 ) additions enhanced the mineralization of white pine (Pinus strobus) cellulose during the summer of 1978. Nitrogen and phosphorus together had no cumulative effect. During the summer of 1979, nitrogen or phosphorus alone had only a slight stimulatory effect on the mineralization of a sedge (Carex aquatilis) cellulose; however, together, they had a dramatic effect. This variable response of mineralization to nutrient addition between 1978 and 1979 was probably attributable to year-to-year variation in nutrient availability within the lake. Cellobiose addition and oxygen depletion inhibited the amount of pine cellulose mineralized. Whereas addition of nitrogen to oxygen-depleted treatments had limited effect, addition of phosphorus resulted in mineralizations equal to or greater than that of the controls. Nitrogen had no effect on mineralization of pine or Carex lignins. Phosphorus, however, inhibited mineralization of both lignins. With Carex lignin, the phosphorus inhibition occurred at a concentration as low as 0.1 μM. The antagonistic role of phosphorus in cellulose and lignin mineralizations may be of significance in understanding the increased proportion of lignin relative to cellulose in decomposing litter

Vegetation composition and soil nutrients status from polyculture to ...

African Journals Online (AJOL)

The findings revealed that the change in micro-environmental conditions as influenced by attitude and seasonality has marked effect on status and release of nutrients in the soil of representative forest stands at markedly difference. The ambient and soil temperature was sharply greater at high altitude (Upper Shillong) and ...

Absorção de nutrientes pelo trigo Absorption of nutrients by wheat plants

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Hermano Gargantini

1973-01-01

Full Text Available Estudou-se a absorção dos nutrientes essenciais das variedades de trigo (Triticum aestivum L. BH 1146 e IAS 3795, cultivadas em vasos de Mitscherlich em casa de vegetação, empregaudo-se Latossolo Vermelho-Escuro fase arenosa, proveniente do município de Capão Bonito. Durante todo o ciclo vegetativo da cultura, a cada 10 dias, colheram-se plantas, para serem analisados os elementos N, P, K, Ca, Mg e S. Verificou-se sensível diferença na entração dos nutrientes, entre ambas as variedades. Assim, enquanto na BH o nitrogênio e, a seguir, o potássio foram os nutrientes absorvidos em maiores quantidades, seguindo-se, em quantidades menores, o fósforo, o cálcio, o ennofre e o magnésio, na variedade IAS o potássio foi absorvido em muito maior quantidade que o nitrogênio, e depois dele, na ordem, o cálcio, o fósforo, o ennofre e o magnésio.In this paper the nutrient absorption by wheat plants is presented. Two varieties of wheat, BH 1146 and IAS 3795, were grown in Mitscherlich pots under greenhouse conditions and supplied with all nutrients, including micronutrients. Plant samples, obtained at 10-day intervals, were analysed for N, P, K, Ca, Mg and S. The amounts of nutrients absorbed were diferent between the two varieties. Furthermore, the BH variety absorbed more nitrogen than other nutrients, while for the IAS variety potassium was the element absorbed in larger amounts. Absorption of P, S, Ca, Mg was small for both varieties.

Nutrient and Light Limitations on Grass Productivity in a Southern African Savanna

Science.gov (United States)

Ries, L. P.; Shugart, H. H.; Caylor, K. K.; Okin, G. S.; Kgope, B.

2006-12-01

Despite the ubiquity of sub-tropical savannas throughout the earth, limitations of savanna productivity are understudied relative to other terrestrial systems. In particular, there has been little attention on the role of phosphorus (P) in savanna productivity and structure. This study examined the role of increased nitrogen (N) and P in grass productivity in a woodland savanna in Botswana. We added aqueous forms of N and P individually and together to selected grasses. During the following growing season we measured foliar nutrient concentrations, aboveground biomass productivity and photosynthetic response at various levels of incident photosynthetically active radiation to estimate the productivity response. As expected, we observed an increase in foliar P concentrations in P and N+P treatments. However, there was no increase in foliar N for any treatments. We also observed a significant increase in net carbon assimilation and Amax for all treatments relative to the control grasses. Despite a higher rate of leaf level carbon assimilation in the N treatment, the aboveground biomass production was smaller than that of the N+P treatment. These results suggest that the aboveground productivity of these woodland savanna grasses is limited by both N and P. Additionally, under constant CO2 availability, photosynthesis appears to be limited by nutrients for light levels greater than 500 μmol m-2s-1. This research will help broaden our understanding of the biogeochemical processes that govern savanna productivity. Ultimately, these data can be used to model canopy productivity and ecological succession of savannas under scenarios in which bush encroachment and desertification may alter light and nutrients availability.

Effects of mineral nutrients on ozone susceptibility of Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Craker, L E

1971-01-01

Susceptibility of Lemna minor L. to ozone injury was influenced by the mineral nutrients available to the Lemna plants. Additional nitrogen or additional iron in the nutrient media respectively enhanced or reduced chlorophyll loss of Lemna plants fumigated with ozone. Lemna plants growing on a nutrient medium lacking copper had significantly less injury from ozone fumigation than Lemna plants growing on a complete nutrient medium. There were apparent interactions among phosphorus and potassium nutrient levels in determing the Lemna plant's susceptibility to ozone.

Changes in Nutrients and Primary Production in Barrow Tundra Ponds Over the Past 40 Years

Science.gov (United States)

Lougheed, V.; Andresen, C.; Hernandez, C.; Miller, N.; Reyes, F.

2012-12-01

The Arctic tundra ponds at the International Biological Program (IBP) site in Barrow, Alaska were studied extensively in the 1970's; however, very little research has occurred there since that time. Due to the sensitivity of this region to climate warming, understanding any changes in the ponds' structure and function over the past 40 years can help identify any potential climate-related impacts. The goal of this study was to determine if the structure and function of primary producers had changed through time, and the association between these changes, urban encroachment and nutrient limitation. Nutrient levels, as well as the biomass of aquatic graminoids (Carex aquatilis and Arctophila fulva), phytoplankton and periphyton were determined in the IBP tundra ponds in both 1971-3 and 2010-12, and in 2010-11 from nearby ponds along an anthropogenic disturbance gradient. Uptake of 14C was also used to measure algal primary production in both time periods and nutrient addition experiments were performed to identify the nutrients limiting algal growth. Similar methods were utilized in the past and present studies. Overall, biomass of graminoids, phytoplankton and periphyton was greater in 2010-12 than that observed in the 1970s. This increased biomass was coincident with warmer water temperatures, increased water column nutrients and deeper active layer depth. Biomass of plants and algae was highest in the ponds closest to the village of Barrow, but no effect of urban encroachment was observed at the IBP ponds. Laboratory incubations indicated that nutrient release from thawing permafrost can explain part of these increases in nutrients and has likely contributed to changes in the primary limiting nutrient. Further studies are necessary to better understand the implications of these trends in primary production to nutrient budgets in the Arctic. The Barrow IBP tundra ponds represent one of the very few locations in the Arctic where long-term data are available on

Effects of mineral nutrients on ozone susceptibility of Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Craker, L.E.

1971-01-01

Susceptibility of Lemna minor L. to ozone injury was influenced by the mineral nutrients available to the Lemna plants. Additional nitrogen or additional iron in the nutrient media respectively enhanced or reduced chlorophyll loss of Lemna plants fumigated with ozone. Lemna plants growing on a nutrient medium lacking copper had significantly less injury from ozone fumigation than Lemna plants growing on a complete nutrient medium. There were apparent interactions among phosphorus and potassium nutrient levels in determing the Lemna plant's susceptibility to ozone.

Relationships between nutrient enrichment, pleurocerid snail density and trematode infection rate in streams

Science.gov (United States)

Ciparis, Serena; Iwanowicz, Deborah D.; Voshell, J. Reese

2013-01-01

Summary 1. Nutrient enrichment is a widespread environmental problem in freshwater ecosystems. Eutrophic conditions caused by nutrient enrichment may result in a higher prevalence of infection by trematode parasites in host populations, due to greater resource availability for the molluscan first intermediate hosts. 2. This study examined relationships among land use, environmental variables indicating eutrophication, population density of the pleurocerid snail, Leptoxis carinata, and trematode infections. Fifteen study sites were located in streams within the Shenandoah River catchment (Virginia, U.S.A.), where widespread nutrient enrichment has occurred. 3. Snail population density had a weak positive relationship with stream water nutrient concentration. Snail population density also increased as human activities within stream catchments increased, but density did not continue to increase in catchments where anthropogenic disturbance was greatest. 4. Cercariae from five families of trematodes were identified in L. carinata, and infection rate was generally low (<10%). Neither total infection rate nor the infection rate of individual trematode types showed a positive relationship with snail population density, nutrients or land use. 5. There were statistically significant but weak relationships between the prevalence of infection by two trematode families and physical and biological variables. The prevalence of Notocotylidae was positively related to water depth, which may be related to habitat use by definitive hosts. Prevalence of Opecoelidae had a negative relationship with orthophosphate concentration and a polynomial relationship with chlorophyll a concentration. Transmission of Opecoelid trematodes between hosts may be inhibited by eutrophic conditions. 6. Leptoxis carinata appears to be a useful species for monitoring the biological effects of eutrophication and investigating trematode transmission dynamics in lotic systems.

The Stoichiometry of Nutrient Release by Terrestrial Herbivores and Its Ecosystem Consequences

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Judith Sitters

2017-04-01

Full Text Available It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N and phosphorus (P recycled through herbivore release (i.e., waste N:P are mainly determined by the stoichiometric composition of the herbivore's food (food N:P and its body nutrient content (body N:P. Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C:N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

Nitrogen regulation of transpiration controls mass-flow acquisition of nutrients.

Science.gov (United States)

Matimati, Ignatious; Verboom, G Anthony; Cramer, Michael D

2014-01-01

Transpiration may enhance mass-flow of nutrients to roots, especially in low-nutrient soils or where the root system is not extensively developed. Previous work suggested that nitrogen (N) may regulate mass-flow of nutrients. Experiments were conducted to determine whether N regulates water fluxes, and whether this regulation has a functional role in controlling the mass-flow of nutrients to roots. Phaseolus vulgaris were grown in troughs designed to create an N availability gradient by restricting roots from intercepting a slow-release N source, which was placed at one of six distances behind a 25 μm mesh from which nutrients could move by diffusion or mass-flow (termed 'mass-flow' treatment). Control plants had the N source supplied directly to their root zone so that N was available through interception, mass-flow, and diffusion (termed 'interception' treatment). 'Mass-flow' plants closest to the N source exhibited 2.9-fold higher transpiration (E), 2.6-fold higher stomatal conductance (gs), 1.2-fold higher intercellular [CO2] (Ci), and 3.4-fold lower water use efficiency than 'interception' plants, despite comparable values of photosynthetic rate (A). E, gs, and Ci first increased and then decreased with increasing distance from the N source to values even lower than those of 'interception' plants. 'Mass-flow' plants accumulated phosphorus and potassium, and had maximum concentrations at 10mm from the N source. Overall, N availability regulated transpiration-driven mass-flow of nutrients from substrate zones that were inaccessible to roots. Thus when water is available, mass-flow may partially substitute for root density in providing access to nutrients without incurring the costs of root extension, although the efficacy of mass-flow also depends on soil nutrient retention and hydraulic properties.

Nutrient allocation among stem, leaf and inflorescence of jatropha plants

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Rosiane L. S. de Lima

2015-08-01

Full Text Available ABSTRACTInformation on the partitioning of nutrients among various organs in jatropha plants, as a complementary tool for the recommendation of fertilization, is still not available. This study aimed to evaluate the contents of macro and micronutrients in stems, leaves and inflorescences of jatropha branches at the beginning of flowering. At the beginning of flowering, adult jatropha plants were sampled and divided into five compartments: inflorescences, leaves from vegetative branches, leaves from flowering branches, stems from vegetative branches and stems from flowering branches. Jatropha inflorescences are a drain of nutrients. Leaves are important sources of nutrients demanded by the inflorescences at the beginning of flowering. The higher allocation of nutrients in the inflorescences suggests the need for preventive/corrective fertilizations, which must be performed at least 30 days before flowering, providing plants with nutrients in adequate amounts for a good yield.

ROLE OF ETHYLENE IN RESPONSES OF PLANTS TO NITROGEN AVAILABILITY

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M Iqbal R Khan

2015-10-01

Full Text Available Ethylene is a plant hormone involved in several physiological processes and regulates the plant development during the whole life. Stressful conditions usually activate ethylene biosynthesis and signalling in plants. The availability of nutrients, shortage or excess, influences plant metabolism and ethylene plays an important role in plant adaptation under suboptimal conditions. Among the plant nutrients, the nitrogen (N is one the most important mineral element required for plant growth and development. The availability of N significantly influences plant metabolism, including ethylene biology. The interaction between ethylene and N affects several physiological process such as leaf gas exchanges, roots architecture, leaf, fruits and flowers development. Low plant N use efficiency leads to N loss and N deprivation, which affect ethylene biosynthesis and tissues sensitivity, inducing cell damage and ultimately lysis. Plants may respond differently to N availability balancing ethylene production through its signalling network. This review discusses the recent advances in the interaction between N availability and ethylene at whole plant and different organ levels, and explores how N availability induces ethylene biology and plant responses. Exogenously applied ethylene seems to cope the stress conditions and improves plant physiological performance. This can be explained considering the expression of ethylene biosynthesis and signalling genes under different N availability. A greater understanding of the regulation of N by means of ethylene modulation may help to increase N use efficiency and directly influence crop productivity under conditions of limited N availability, leading to positive effects on the environment. Moreover, efforts should be focused on the effect of N deficiency or excess in fruit trees, where ethylene can have detrimental effects especially during postharvest.

Successional dynamics drive tropical forest nutrient limitation

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Chou, C.; Hedin, L. O. O.

2017-12-01

It is increasingly recognized that nutrients such as N and P may significantly constrain the land carbon sink. However, we currently lack a complete understanding of these nutrient cycles in forest ecosystems and how to incorporate them into Earth System Models. We have developed a framework of dynamic forest nutrient limitation, focusing on the role of secondary forest succession and canopy gap disturbances as bottlenecks of high plant nutrient demand and limitation. We used succession biomass data to parameterize a simple ecosystem model and examined the dynamics of nutrient limitation throughout tropical secondary forest succession. Due to the patterns of biomass recovery in secondary tropical forests, we found high nutrient demand from rapid biomass accumulation in the earliest years of succession. Depending on previous land use scenarios, soil nutrient availability may also be low in this time period. Coupled together, this is evidence that there may be high biomass nutrient limitation early in succession, which is partially met by abundant symbiotic nitrogen fixation from certain tree species. We predict a switch from nitrogen limitation in early succession to one of three conditions: (i) phosphorus only, (ii) phosphorus plus nitrogen, or (iii) phosphorus, nitrogen, plus light co-limitation. We will discuss the mechanisms that govern the exact trajectory of limitation as forests build biomass. In addition, we used our model to explore scenarios of tropical secondary forest impermanence and the impacts of these dynamics on ecosystem nutrient limitation. We found that secondary forest impermanence exacerbates nutrient limitation and the need for nitrogen fixation early in succession. Together, these results indicate that biomass recovery dynamics early in succession as well as their connection to nutrient demand and limitation are fundamental for understanding and modeling nutrient limitation of the tropical forest carbon sink.

Nutrient Availability and Changes on Chemical Attributes of a Paleudult Soil Amended with Liquid Sewage Sludge and Cropped with Surinam Grass

International Nuclear Information System (INIS)

Ceolato, L.C.; Berton, R.S.; Coscione, A.R.

2011-01-01

The liquid sewage sludge (LSS) was applied on a field experiment during four years at successive applications to evaluate the changes in soil attributes and on Surinam grass (Brachiaria decumbens) uptake of nutrients. A randomized blocks experimental design, with two treatments (with and without LSS) and three repetitions, was used. Land application of LSS did not alter soil organic matter and exchangeable K until 40 cm depth. However, it increased soil ph, base saturation, labile P, and available Zn and did not change the concentrations of available B (hot water) and Cu, Fe, and Mn (DTPA) at 0-20 cm and 20-40 cm depths and LSS was a source of N, K, P, Ca, Mg, and Zn for the grass, but decreased leaf Mn concentration.

Nutrient and Coliform Loading (NCL)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is a database of available fecal coliform bacteria, fecal streptococci bacteria, and nutrient loading data. Loading for contaminants other than fecal coliform...

Maternal Nutrition During Pregnancy: Intake of Nutrients Important for Bone Health.

Science.gov (United States)

Hyde, Natalie K; Brennan-Olsen, Sharon L; Bennett, Kathy; Moloney, David J; Pasco, Julie A

2017-04-01

Objectives Maternal nutrition during pregnancy plays an important role in predisposing offspring to the development of chronic disease in adulthood, including osteoporosis. Our aim was to investigate maternal dietary intakes during pregnancy, with a focus on nutrients important for skeletal development in the offspring. Methods In this case-control study, cases were pregnant women recruited for the Vitamin D in Pregnancy Study (n = 350, age 20-40 years) and controls were non-pregnant peers participating in the Geelong Osteoporosis Study (n = 305, age 20-40 years). Dietary intakes of nutrients were quantified using a validated food frequency questionnaire. Results Compared to controls, cases consumed more energy [median (interquartile range): 7831 (6506-9461) vs. 7136 (6112-8785) kJ/day]; median intakes for cases were greater for carbohydrates [206.2 (172.5-249.9) vs. 188.2 (147.7-217.5) g/day], fat [77.9 (60.3-96.6) vs. 72.1 (53.3-87.4) g/day], potassium [2860 (2363-3442) vs. 2606 (2166-3442) mg/day] and calcium [1022 (819-1264) vs. 918 (782-1264) mg/day] (all p ≤ 0.05). However, pregnant women were not consuming greater amounts of those nutrients which had an increased demand (protein, magnesium, phosphorus and zinc). Similarly, this translated to the likelihood of achieving national recommendations for corresponding nutrients. Conclusions for Practice Compared to their non-pregnant peers, pregnant women were more likely to meet dietary recommendations for calcium and potassium; however, this was not the pattern observed for protein, magnesium and zinc. Future public health messages should perhaps focus on increasing awareness of the importance of all these nutrients during pregnancy.

Impacts of Cover Crops on Water and Nutrient Dynamics in Agroecosystems

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Williard, K.; Swanberg, S.; Schoonover, J.

2013-05-01

Intensive cropping systems of corn (Zea Mays L.) and soybeans (Glycine max) are commonly leaky systems with respect to nitrogen (N). Reactive N outputs from agroecosystems can contribute to eutrophication and hypoxic zones in downstream water bodies and greenhouse gas (N2O) emissions. Incorporating cover crops into temperate agroecosystem rotations has been promoted as a tool to increase nitrogen use efficiency and thus limit reactive N outputs to the environment. Our objective was determine how cereal rye (Secale cereal L.) and annual ryegrass (Lolium multiflorum) cover crops impact nutrient and soil water dynamics in an intensive corn and soybean cropping rotation in central Illinois. Cover crops were planted in mid to late October and terminated in early April prior to corn or soybean planting. In the spring just prior to cover crop termination, soil moisture levels were lower in the cover crop plots compared to no cover plots. This can be a concern for the subsequent crop in relatively dry years, which the Midwestern United States experienced in 2012. No cover plots had greater nutrient leaching below the rooting zone compared to cover crop areas, as expected. The cover crops were likely scavenging nutrients during the fall and early spring and should provide nutrients to the subsequent crop via decomposition and mineralization of the cover crop residue. Over the long term, cover crop systems should produce greater inputs and cycling of carbon and N, increasing the productivity of crops due to the long-term accumulation of soil organic matter. This study demonstrates that there may be short term trade-offs in reduced soil moisture levels that should be considered alongside the long term nutrient scavenging and recycling benefits of cover crops.

Nutrient cycling strategies.

NARCIS (Netherlands)

Breemen, van N.

1995-01-01

This paper briefly reviews pathways by which plants can influence the nutrient cycle, and thereby the nutrient supply of themselves and of their competitors. Higher or lower internal nutrient use efficiency positively feeds back into the nutrient cycle, and helps to increase or decrease soil

Nutrient partitioning and response to insulin challenge at different ...

African Journals Online (AJOL)

Milk yield was not reduced by the low plane of nutrition in either genotype. The sustained rate of milk production at the low level of nutrition was achieved by increased mobilisation of endogenous nutrients from body reserves, evidenced as a greater loss of body mass at the low plane of nutrition in both breeds. The Saanen ...

Parasite and nutrient enrichment effects on Daphnia interspecific competition

NARCIS (Netherlands)

Decaestecker, Ellen; Verreydt, Dino; De Meester, Luc; Declerck, Steven A.J.

2015-01-01

Increased productivity due to nutrient enrichment is hypothesized to affect density-dependent processes, such as transmission success of horizontally transmitting parasites. Changes in nutrient availability can also modify the stoichiometry and condition of individual hosts, which may affect their

Seasonal variability in nitrate and phosphate uptake kinetics in a forested headwater stream using pulse nutrient additions

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Griffiths, N. A.; Mulholland, P. J.

2011-12-01

We used the Tracer Additions for Spiraling Curve Characterization (TASCC) approach to quantify seasonal variability in ambient nutrient spiraling metrics and nutrient uptake kinetics in the West Fork of Walker Branch, a forested headwater stream in eastern Tennessee, USA. We performed instantaneous additions of nitrate (NO3-) and phosphate (PO4-3) separately with a conservative tracer (chloride, Cl-) during the following biologically-important time periods: autumn (during leaf fall, high organic matter [OM] standing stocks), winter (low OM standing stocks), spring (prior to canopy closure), and summer (closed canopy). We predicted that nutrient demand would be highest during autumn and spring, as OM inputs fuel heterotrophic respiration and high light availability stimulates autotrophic production, respectively. The measured ambient PO4-3 uptake rates (Vf-amb) followed our predictions, with the highest Vf-amb rates in autumn (Vf-amb = 2.8 mm/min) and spring (Vf-amb = 2.9 mm/min), and undetectable uptake in winter. Further, maximum areal PO4-3 uptake rates (Umax) were higher in autumn (Umax = 297 μg/m2/min) than spring (Umax = 106 μg/m2/min), possibly due to greater nutrient demand of heterotrophs on leaf litter accumulations. Contrary to our predictions, ambient NO3- uptake rates were highest in autumn and winter (autumn: Vf-amb = 2.8 mm/min, winter: Vf-amb = 2.4 mm/min), and lowest in spring (Vf-amb = 1.0 mm/min). The higher than expected Vf-amb rate in winter may be due to higher stream metabolism rates and thus greater nitrogen demand; the lower than expected Vf-amb rate in spring may reflect an alleviation of nitrogen demand due to high ammonium concentrations during this time. As the demand for both nitrogen and phosphorus in Walker Branch is greatest in autumn, future work will characterize how nutrient metrics change during this dynamic time period (i.e., before, during, and after leaf fall).

Fish-derived nutrient hotspots shape coral reef benthic communities.

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Shantz, Andrew A; Ladd, Mark C; Schrack, Elizabeth; Burkepile, Deron E

2015-12-01

Animal-derived nutrients play an important role in structuring nutrient regimes within and between ecosystems. When animals undergo repetitive, aggregating behavior through time, they can create nutrient hotspots where rates of biogeochemical activity are higher than those found in the surrounding environment. In turn, these hotspots can influence ecosystem processes and community structure. We examined the potential for reef fishes from the family Haemulidae (grunts) to create nutrient hotspots and the potential impact of these hotspots on reef communities. To do so, we tracked the schooling locations of diurnally migrating grunts, which shelter at reef sites during the day but forage off reef each night, and measured the impact of these fish schools on benthic communities. We found that grunt schools showed a high degree of site fidelity, repeatedly returning to the same coral heads. These aggregations created nutrient hotspots around coral heads where nitrogen and phosphorus delivery was roughly 10 and 7 times the respective rates of delivery to structurally similar sites that lacked schools of these fishes. In turn, grazing rates of herbivorous fishes at grunt-derived hotspots were approximately 3 times those of sites where grunts were rare. These differences in nutrient delivery and grazing led to distinct benthic communities with higher cover of crustose coralline algae and less total algal abundance at grunt aggregation sites. Importantly, coral growth was roughly 1.5 times greater at grunt hotspots, likely due to the important nutrient subsidy. Our results suggest that schooling reef fish and their nutrient subsidies play an important role in mediating community structure on coral reefs and that overfishing may have important negative consequences on ecosystem functions. As such, management strategies must consider mesopredatory fishes in addition to current protection often offered to herbivores and top-tier predators. Furthermore, our results suggest that

Sun-induced Chlorophyll fluorescence and PRI improve remote sensing GPP estimates under varying nutrient availability in a typical Mediterranean savanna ecosystem

Science.gov (United States)

Perez-Priego, O.; Guan, J.; Rossini, M.; Fava, F.; Wutzler, T.; Moreno, G.; Carvalhais, N.; Carrara, A.; Kolle, O.; Julitta, T.; Schrumpf, M.; Reichstein, M.; Migliavacca, M.

2015-07-01

This study investigates the performances of different optical indices to estimate gross primary production (GPP) of herbaceous stratum in a Mediterranean savanna with different Nitrogen (N) and Phosphorous (P) availability. Sun-induced chlorophyll Fluorescence yield computed at 760 nm (Fy760), scaled-photochemical reflectance index (sPRI), MERIS terrestrial-chlorophyll index (MTCI) and Normalized difference vegetation index (NDVI) were computed from near-surface field spectroscopy measurements collected using high spectral resolution spectrometers covering the visible near-infrared regions. GPP was measured using canopy-chambers on the same locations sampled by the spectrometers. We hypothesized that light-use efficiency (LUE) models driven by remote sensing quantities (RSM) can better track changes in GPP caused by nutrient supplies compared to those driven exclusively by meteorological data (MM). Particularly, we compared the performances of different RSM formulations - relying on the use of Fy760 or sPRI as proxy for LUE and NDVI or MTCI as fraction of absorbed photosynthetically active radiation (fAPAR) - with those of classical MM. Results showed significantly higher GPP in the N fertilized experimental plots during the growing period. These differences in GPP disappeared in the drying period when senescence effects masked out potential differences due to plant N content. Consequently, although MTCI was tightly related to plant N content (r2 = 0.86, p < 0.01), it was poorly related to GPP (r2 = 0.45, p < 0.05). On the contrary sPRI and Fy760 correlated well with GPP during the whole measurement period. Results revealed that the relationship between GPP and Fy760 is not unique across treatments but it is affected by N availability. Results from a cross validation analysis showed that MM (AICcv = 127, MEcv = 0.879) outperformed RSM (AICcv = 140, MEcv = 0.8737) when soil moisture was used to constrain the seasonal dynamic of LUE. However, residual analyses

ENSO-driven nutrient variability recorded by central equatorial Pacific corals

Science.gov (United States)

LaVigne, M.; Nurhati, I. S.; Cobb, K. M.; McGregor, H. V.; Sinclair, D. J.; Sherrell, R. M.

2012-12-01

Recent evidence for shifts in global ocean primary productivity suggests that surface ocean nutrient availability is a key link between global climate and ocean carbon cycling. Time-series records from satellite, in situ buoy sensors, and bottle sampling have documented the impact of the El Niño Southern Oscillation (ENSO) on equatorial Pacific hydrography and broad changes in biogeochemistry since the late 1990's, however, data are sparse prior to this. Here we use a new paleoceanographic nutrient proxy, coral P/Ca, to explore the impact of ENSO on nutrient availability in the central equatorial Pacific at higher-resolution than available from in situ nutrient data. Corals from Christmas (157°W 2°N) and Fanning (159°W 4°N) Islands recorded a well-documented decrease in equatorial upwelling as a ~40% decrease in P/Ca during the 1997-98 ENSO cycle, validating the application of this proxy to Pacific Porites corals. We compare the biogeochemical shifts observed through the 1997-98 event with two pre-TOGA-TAO ENSO cycles (1982-83 and 1986-87) reconstructed from a longer Christmas Island core. All three corals revealed ~30-40% P/Ca depletions during ENSO warming as a result of decreased regional wind stress, thermocline depth, and equatorial upwelling velocity. However, at the termination of each El Niño event, surface nutrients did not return to pre-ENSO levels for ~4-12 months after, SST as a result of increased biological draw down of surface nutrients. These records demonstrate the utility of high-resolution coral nutrient archives for understanding the impact of tropical Pacific climate on the nutrient and carbon cycling of this key region.

Calagem em solos de várzea e a disponibilidade de nutrientes na solução do solo após o alagamento Liming in lowland soils and nutrient availability in soil solution after flooding

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Leandro Souza da Silva

2005-10-01

Full Text Available A calagem do solo altera o pH e, conseqüentemente, influencia no processo de redução dos solos submetidos ao alagamento para o cultivo do arroz irrigado, alterando a disponibilidade de nutrientes na solução do solo. Entretanto, a recomendação de calcário para o arroz irrigado é variável, implicando em diferentes quantidades a aplicar, dependendo da situação. Assim, o objetivo deste trabalho foi avaliar a liberação de nutrientes para a solução do solo após o alagamento, em três solos de várzea com diferentes valores de pH, resultantes da aplicação de diferentes quantidades de calcário. Amostras de solos de várzea foram coletadas da camada de 0 a 20 cm em áreas de produção de arroz nos municípios de Cachoeirinha/RS (Gleissolo, Faxinal do Soturno (Planossolo 1 e Santa Maria (Planossolo 2, as quais foram misturadas com calcário para comporem os seguintes tratamentos: zero; ½ SMP e 1 SMP para pH 5,5 e 1 SMP para pH 6,0. Após 90 dias de incubação, as amostras foram acondicionadas em vasos plásticos com um dispositivo para coleta da solução do solo e alagadas. Aos 2, 8, 15, 22, 28, 42 e 56 dias de alagamento foram retiradas amostras da solução do solo e determinados os teores de Fe, Ca, Mg, K e P. Com os maiores valores de pH, diminuíram os teores de ferro na solução, aumentaram os de cálcio e magnésio e não afetaram os teores de fósforo e potássio. As concentrações dos nutrientes e as mudanças provocadas pela calagem foram diferentes nos três solos.Liming changes soil pH, reduction process and nutrient availability in flooded soils used for rice production. However, the lime requirement for rice production is variable, depending on the situation. The objective of the experiment was to evaluate the nutrient release to soil solution after flooding of three lowland soils with different pH values resulting from different lime application. Soils samples from 0 to 20 cm were collected in three places and

Alocação de nutrientes em plantios de eucalipto no Brasil Nutrient allocation in eucalypt plantations in Brazil

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Reynaldo Campos Santana

2008-12-01

Full Text Available Práticas de manejo florestal podem alterar a exportação de nutrientes do sítio. Este trabalho teve por objetivo estimar o conteúdo de nutrientes em árvores de eucalipto, em diferentes regiões do Brasil. Avaliou-se a influência de algumas características climáticas na produção e no conteúdo de nutrientes na biomassa, utilizando-se o banco de dados do Programa de Pesquisa em Solos e Nutrição de Eucalipto do Departamento de Solos - UFV. As características climáticas foram um importante componente dos modelos. A produção de biomassa e o conteúdo de nutrientes foram positivamente relacionados entre si e ambos foram menores nas regiões com menor disponibilidade de água. As estimativas apontaram que até à idade de 4,5 anos pós-plantio acumulam-se as maiores proporções de nutrientes (68 % do N, 69 % do P, 67 % do K, 63 % do Ca e 68 % do Mg para a idade de corte de 6,5 anos. Isto indica que, após 4,5 anos, o potencial de resposta à aplicação de fertilizantes é menor. O conteúdo estimado de nutrientes acumulados na copa e na casca representou 65, 70, 64, 79 e 79 %, de N, P, K, Ca e Mg, respectivamente, até 6,5 anos de idade. Assim, a colheita apenas do lenho representa expressiva redução na exportação desses nutrientes proporcionando maior sustentabilidade da produção nas plantações de eucalipto.Forest management practices can alter nutrient exportation from the site. The purpose of this study was to estimate nutrient contents in the aboveground biomass of eucalyptus plantations in Brazil. The influence of key climatic variables on eucalypt productivity and nutrient content was evaluated, using the database from the Reserch Programa on Soil and Eucalyptus Nutrition of the Soil Science, Departament - Federal University of Viçosa, Minas Gerais State, Brazil. Climatic characteristics were an important component of the models. In regions with low water availability the nutrient accumulation in aboveground biomass as

Temporal-spatial dynamics in orthoptera in relation to nutrient availability and plant species richness.

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Rob J J Hendriks

Full Text Available Nutrient availability in ecosystems has increased dramatically over the last century. Excess reactive nitrogen deposition is known to negatively impact plant communities, e.g. by changing species composition, biomass and vegetation structure. In contrast, little is known on how such impacts propagate to higher trophic levels. To evaluate how nitrogen deposition affects plants and herbivore communities through time, we used extensive databases of spatially explicit historical records of Dutch plant species and Orthoptera (grasshoppers and crickets, a group of animals that are particularly susceptible to changes in the C:N ratio of their resources. We use robust methods that deal with the unstandardized nature of historical databases to test whether nitrogen deposition levels and plant richness changes influence the patterns of richness change of Orthoptera, taking into account Orthoptera species functional traits. Our findings show that effects indeed also propagate to higher trophic levels. Differences in functional traits affected the temporal-spatial dynamics of assemblages of Orthoptera. While nitrogen deposition affected plant diversity, contrary to our expectations, we could not find a strong significant effect of food related traits. However we found that species with low habitat specificity, limited dispersal capacity and egg deposition in the soil were more negativly affected by nitrogen deposition levels. Despite the lack of significant effect of plant richness or food related traits on Orthoptera, the negative effects of nitrogen detected within certain trait groups (e.g. groups with limited disperse ability could be related to subtle changes in plant abundance and plant quality. Our results, however, suggest that the changes in soil conditions (where many Orthoptera species lay their eggs or other habitat changes driven by nitrogen have a stronger influence than food related traits. To fully evaluate the negative effects of nitrogen

ENVIRONMENTAL ACCOUNTING IN AGRICULTURE: NUTRIENT ACCOUNTING AND OTHER ASPECTS

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P URFI

2003-04-01

Full Text Available While traditional accounting focuses on accounting for capital assets, costs, yields valued and sold in the market, environmental accounting intends to do the same with non-marketed capital assets, costs and yields, that is, externalities. The farm level nutrient balances are based on an input-output comparison, in which the nutrients entering the farm within inputs are compared to nutrients leaving the farm within the sold products. The method considers the amounts of nutrients entering the farm but not leaving it with the products to be wastes polluting the environment. The weakness of this approach is the handling of stock changes. In a farming year high amounts of nutrients contained in unsold products are not wastes, nor are they stored in the soil, but are stored in the stocks. To handle this problem the concepts of external nutrient balance and internal nutrient balance are introduced, and are tested in case studies of two Hungarian mixed farms.

Mariculture: significant and expanding cause of coastal nutrient enrichment

International Nuclear Information System (INIS)

Bouwman, Lex; Beusen, Arthur; Glibert, Patricia M; Overbeek, Ciska; Pawlowski, Marcin; Herrera, Jorge; Mulsow, Sandor; Yu, Rencheng; Zhou, Mingjiang

2013-01-01

Mariculture (marine aquaculture) generates nutrient waste either through the excretion by the reared organisms, or through direct enrichment by, or remineralization of, externally applied feed inputs. Importantly, the waste from fish or shellfish cannot easily be managed, as most is in dissolved form and released directly to the aquatic environment. The release of dissolved and particulate nutrients by intensive mariculture results in increasing nutrient loads (finfish and crustaceans), and changes in nutrient stoichiometry (all mariculture types). Based on different scenarios, we project that nutrients from mariculture will increase up to six fold by 2050 with exceedance of the nutrient assimilative capacity in parts of the world where mariculture growth is already rapid. Increasing nutrient loads and altered nutrient forms (increased availability of reduced relative to oxidized forms of nitrogen) and/or stoichiometric proportions (altered nitrogen:phosphorus ratios) may promote an increase in harmful algal blooms (HABs) either directly or via stimulation of algae on which mixotrophic HABs may feed. HABs can kill or intoxicate the mariculture product with severe economic losses, and can increase risks to human health. (letter)

Plant species occurrence patterns in Eurasian grasslands reflect adaptation to nutrient ratios

NARCIS (Netherlands)

Roeling, Ineke S.; Ozinga, Wim A.; van Dijk, Jerry; Eppinga, Maarten B.; Wassen, Martin J.

2018-01-01

Previous studies of Eurasian grasslands have suggested that nutrient ratios, rather than absolute nutrient availabilities and associated productivity, may be driving plant species richness patterns. However, the underlying assumption that species occupy distinct niches along nutrient ratio gradients

Gustatory and metabolic perception of nutrient stress in Drosophila.

Science.gov (United States)

Linford, Nancy J; Ro, Jennifer; Chung, Brian Y; Pletcher, Scott D

2015-02-24

Sleep loss is an adaptive response to nutrient deprivation that alters behavior to maximize the chances of feeding before imminent death. Organisms must maintain systems for detecting the quality of the food source to resume healthy levels of sleep when the stress is alleviated. We determined that gustatory perception of sweetness is both necessary and sufficient to suppress starvation-induced sleep loss when animals encounter nutrient-poor food sources. We further find that blocking specific dopaminergic neurons phenocopies the absence of gustatory stimulation, suggesting a specific role for these neurons in transducing taste information to sleep centers in the brain. Finally, we show that gustatory perception is required for survival, specifically in a low nutrient environment. Overall, these results demonstrate an important role for gustatory perception when environmental food availability approaches zero and illustrate the interplay between sensory and metabolic perception of nutrient availability in regulating behavioral state.

Evaluation of high nutrient diets on litter performance of heat-stressed lactating sows

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Yohan Choi

2017-11-01

Full Text Available Objective The present study investigated the litter performance of multiparous sows fed 3% and 6% densified diets at farrowing to weaning during summer with mean maximum room temperature of 30.5°C. Methods A total of 60 crossbred multiparous sows were allotted to one of three treatments based on body weight according to a completely randomized design. Three different nutrient levels based on NRC were applied as standard diet (ST; metabolizable energy, 3,300 kcal/kg, high nutrient level 1 (HE1; ST+3% higher energy and 16.59% protein and high nutrient level 2 (HE2; ST+6% higher energy and 17.04% protein. Results There was no variation in the body weight change. However, backfat thickness change tended to reduce in HE1 in comparison to ST treatment. Dietary treatments had no effects on feed intake, daily energy intake and weaning-to-estrus interval in lactating sows. Litter size, litter weight at weaning and average daily gain of piglets were significantly greater in sows in HE1 compared with ST, however, no difference was observed between HE2 and ST. Increasing the nutrient levels had no effects on the blood urea nitrogen, glucose, triglyceride, and creatinine at post-farrowing and weaning time. The concentration of follicle stimulating hormone, cortisol and insulin were not affected by dietary treatments either in post-farrowing or weaning time. The concentration of blood luteinizing hormone of sows in ST treatment was numerically less than sows in HE2 treatment at weaning. Milk and colostrum compositions such as protein, fat and lactose were not affected by the treatments. Conclusion An energy level of 3,400 kcal/kg (14.23 MJ/kg with 166 g/kg crude protein is suggested as the optimal level of dietary nutrients for heat stressed lactating sows with significant beneficial effects on litter size.

Food web interactions and nutrients dynamics in polyculture ponds

NARCIS (Netherlands)

Rahman, M.M.

2006-01-01

Artificial feed and fertilizers are the main sources of nutrients supporting fish growth in aquaculture ponds. The majority of the added nutrients are lost to the sediment, where they are no longer available for natural food production. By increasing resuspension of the sediment through the

Trends in nutrients

Science.gov (United States)

Heathwaite, A.L.; Johnes, P.J.; Peters, N.E.

1996-01-01

The roles of nitrogen (N) and phosphorus (P) as key nutrients determining the trophic status of water bodies are examined, and evidence reviewed for trends in concentrations of N and P species which occur in freshwaters, primarily in northern temperate environments. Data are reported for water bodies undergoing eutrophication and acidification, especially water bodies receiving increased nitrogen inputs through the atmospheric deposition of nitrogen oxides (NOx). Nutrient loading on groundwaters and surface freshwaters is assessed with respect to causes and rates of (change, relative rates of change for N and P, and implications of change for the future management of lakes, rivers and groundwaters. In particular, the nature and emphasis of studies for N species and P fractions in lakes versus rivers and groundwaters are contrasted. This review paper primarily focuses on results from North America and Europe, particularly for the UK where a wide range of data sets exists. Few nutrient loading data have been published on water bodies in less developed countries; however, some of the available data are presented to provide a global perspective. In general, N and P concentrations have increased dramatically (>20 times background concentrations) in many areas and causes vary considerably, ranging from urbanization to changes in agricultural practices.

Review on Periphyton as Mediator of Nutrient Transfer in Aquatic Ecosystems

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Surjya K. Saikia

2011-12-01

Full Text Available In the studies of aquatic ecology, periphyton has been uncared for despite its vital role in nutrient uptake and transfer to the upper trophic organisms. Being the component of food chain as attached organism it takes part in nutrient cycling in the ecosystem like that of suspended planktonic counterparts. The present review, with an aim to understand the role of periphyton in nutrient transfer from benthic environment to upper trophic level, focuses many aspects of periphyton-nutrient relationship based on available literatures. It also attempts to redefine periphyton, as a part of biofilm, harboring nutrient components like protein, fat and carbohydrate preferably in its extracellular polymeric substance (EPS, cyanobacteria, diatom and other algal communities. In addition to physical processes, nutrient uptake by periphyton is catalyzed by enzymes like Nitrogen Reductase and Alkaline Phosphatase from the environment. This uptake and transfer is further regulated by periphytic C: nutrient (N or P stoichiometry, colonization time, distribution of periphyton cover on sediments and macrophytes, macronutrient concentration, grazing, sloughing, temperature, and advective transport. The Carbon (C sources of periphyton are mainly dissolve organic matter and photosynthetic C that enters into higher trophic levels through predation and transfers as C-rich nutrient components. Despite of emerging interests on utilizing periphyton as nutrient transfer tool in aquatic ecosystem, the major challenges ahead for modern aquatic biologists lies on determining nutrient uptake and transfer rate of periphyton, periphytic growth and simulating nutrient models of periphyton to figure a complete energy cycle in aquatic ecosystem.

Improving Lowland Rice (O. sativa L. cv. MR219) Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Crude Humic Substances.

Science.gov (United States)

Palanivell, Perumal; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad; Jalloh, Mohamadu Boyie; Susilawati, Kasim

2015-01-01

High cation exchange capacity and organic matter content of crude humic substances from compost could be exploited to reduce ammonia loss from urea and to as well improve rice growth and soil chemical properties for efficient nutrients utilization in lowland rice cultivation. Close-dynamic air flow system was used to determine the effects of crude humic substances on ammonia volatilization. A pot experiment was conducted to determine the effects of crude humic substances on rice plant growth, nutrients uptake, nutrients recovery, and soil chemical properties using an acid soil mixed with three rates of crude humic substances (20, 40, and 60 g pot(-1)). Standard procedures were used to evaluate rice plant dry matter production, nutrients uptake, nutrients recovery, and soil chemical properties. Application of crude humic substances increased ammonia volatilization. However, the lowest rate of crude humic substances (20 g pot(-1)) significantly improved total dry matter, nutrients uptake, nutrients recovery, and soil nutrients availability compared with crude humic substances (40 and 60 g pot(-1)) and the normal fertilization. Apart from improving growth of rice plants, crude humic substances can be used to ameliorate acid soils in rice cultivation. The findings of this study are being validated in our ongoing field trials.

Dietary nutrients associated with preservation of lung function in Hispanic and non-Hispanic white smokers from New Mexico

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Leng S

2017-10-01

Full Text Available Shuguang Leng,1,2 Maria A Picchi,1 Yohannes Tesfaigzi,3 Guodong Wu,1 W James Gauderman,4 Fadi Xu,5 Frank D Gilliland,4 Steven A Belinsky1,2,6 1The Lung Cancer Program, Lovelace Respiratory Research Institute, 2Cancer Control Research Program, University of New Mexico Comprehensive Cancer Center, 3COPD Program, Lovelace Respiratory Research Institute, Albuquerque, NM, 4Keck School of Medicine, University of Southern California, Los Angeles, CA, 5Pathophysiology Program, Lovelace Respiratory Research Institute, 6Cancer Genetics and Epigenetics Program, University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA Background: COPD is the third leading cause of death in the United States. Cigarette smoking accelerates the age-related forced expiratory volume in 1 s (FEV1 decline, an important determinant for the genesis of COPD. Hispanic smokers have lower COPD prevalence and FEV1 decline than non-Hispanic whites (NHWs. Patients and methods: A nutritional epidemiological study was conducted in the Lovelace Smokers cohort (LSC; n=1,829 and the Veterans Smokers cohort (n=508 to identify dietary nutrients (n=139 associated with average FEV1 and its decline and to assess whether nutrient intakes could explain ethnic disparity in FEV1 decline between Hispanics and NHW smokers. Results: Nutrients discovered and replicated to be significantly associated with better average FEV1 included magnesium, folate, niacin, vitamins A and D, eicosenoic fatty acid (20:1n9, eicosapentaenoic acid (20:5n3, docosapentaenoic acid (DPA; 22:5n3, docosahexaenoic acid (22:6n3, and fiber. In addition, greater intakes of eicosenoic fatty acid and DPA were associated with slower FEV1 decline in the LSC. Among omega 3 polyunsaturated fatty acids, DPA is the most potent nutrient associated with better average FEV1 and slower FEV1 decline. Adverse effect of continuous current smoking on FEV1 decline was completely negated in LSC members with high DPA intake (>20�

Diagnosis of the nutrient compositional space of fruit crops

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Léon-Étienne Parent

2011-03-01

Full Text Available Tissue analysis is a useful tool for the nutrient management of fruit orchards. The mineral composition of diagnostic tissues expressed as nutrient concentration on a dry weight basis has long been used to assess the status of 'pure' nutrients. When nutrients are mixed and interact in plant tissues, their proportions or concentrations change relatively to each other as a result of synergism, antagonism, or neutrality, hence producing resonance within the closed space of tissue composition. Ternary diagrams and nutrient ratios are early representations of interacting nutrients in the compositional space. Dual and multiple interactions were integrated by the Diagnosis and Recommendation Integrated System (DRIS into nutrient indexes and by Compositional Nutrient Diagnosis into centered log ratios (CND-clr. DRIS has some computational flaws such as using a dry matter index that is not a part as well as nutrient products (e.g. NxCa instead of ratios. DRIS and CND-clr integrate all possible nutrient interactions without defining an ad hoc interactive model. They diagnose D components while D-1 could be diagnosed in the D-compositional Hilbert space. The isometric log ratio (ilr coordinates overcome these problems using orthonormal binary nutrient partitions instead of dual ratios. In this study, it is presented a nutrient interactive model as well as computation methods for DRIS and CND-clr and CND-ilr coordinates (CND-ilr using leaf analytical data from an experimental apple orchard in Southwestern Quebec, Canada. It was computed the Aitchison and Mahalanobis distances across ilr coordinates as measures of nutrient imbalance. The effect of changing nutrient concentrations on ilr coordinates are simulated to identify the ones contributing the most to nutrient imbalance.

Detecting terrestrial nutrient limitation: a global meta-analysis of foliar nutrient concentrations after fertilization

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Rebecca eOstertag

2016-03-01

Full Text Available Examining foliar nutrient concentrations after fertilization provides an alternative method for detecting nutrient limitation of ecosystems, which is logistically simpler to measure than biomass change. We present a meta-analysis of response ratios of foliar nitrogen and phosphorus (RRN, RRP after addition of fertilizer of nitrogen (N, phosphorus (P, or the two elements in combination, in relation to climate, ecosystem type, life form, family, and methodological factors. Results support other meta-analyses using biomass, and demonstrate there is strong evidence for nutrient limitation in natural communities. However, because N fertilization experiments greatly outnumber P fertilization trials, it is difficult to discern the absolute importance of N vs. P vs. co-limitation across ecosystems. Despite these caveats, it is striking that results did not follow conventional wisdom that temperate ecosystems are N-limited and tropical ones are P-limited. In addition, the use of ratios of N-to-P rather than response ratios also are a useful index of nutrient limitation, but due to large overlap in values, there are unlikely to be universal cutoff values for delimiting N vs. P limitation. Differences in RRN and RRP were most significant across ecosystem types, plant families, life forms, and between competitive environments, but not across climatic variables.

Rhizosphere priming: a nutrient perspective

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Feike Auke Dijkstra

2013-07-01

Full Text Available Rhizosphere priming is the change in decomposition of soil organic matter (SOM caused by root activity. Rhizosphere priming plays a crucial role in soil carbon (C dynamics and their response to global climate change. Rhizosphere priming may be affected by soil nutrient availability, but rhizosphere priming itself can also affect nutrient supply to plants. These interactive effects may be of particular relevance in understanding the sustained increase in plant growth and nutrient supply in response to a rise in atmospheric CO2 concentration. We examined how these interactions were affected by elevated CO2 in two similar semiarid grassland field studies. We found that an increase in rhizosphere priming enhanced the release of nitrogen (N through decomposition of a larger fraction of SOM in one study, but not in the other. We postulate that rhizosphere priming may enhance N supply to plants in systems that are N limited, but that rhizosphere priming may not occur in systems that are phosphorus (P limited. Under P limitation, rhizodeposition may be used for mobilisation of P, rather than for decomposition of SOM. Therefore, with increasing atmospheric CO2 concentrations, rhizosphere priming may play a larger role in affecting C sequestration in N poor than in P poor soils.

Strain Identity of the Ectomycorrhizal Fungus Laccaria bicolor Is More Important than Richness in Regulating Plant and Fungal Performance under Nutrient Rich Conditions

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Christina Hazard

2017-09-01

Full Text Available Effects of biodiversity on productivity are more likely to be expressed when there is greater potential for niche complementarity. In soil, chemically complex pools of nutrient resources should provide more opportunities for niche complementarity than chemically simple pools. Ectomycorrhizal (ECM fungal genotypes can exhibit substantial variation in nutrient acquisition traits and are key components of soil biodiversity. Here, we tested the hypothesis that increasing the chemical complexity and forms of soil nutrients would enhance the effects of intraspecific ECM diversity on host plant and fungal productivity. In pure culture, we found substantial variation in growth of strains of the ECM fungus Laccaria bicolor on a range of inorganic and organic forms of nutrients. Subsequent experiments examined the effects of intraspecific identity and richness using Scots pine (Pinus sylvestris seedlings colonized with different strains of L. bicolor growing on substrates supplemented with either inorganic or organic forms of nitrogen and phosphorus. Intraspecific identity effects on plant productivity were only found under the inorganic nutrient amendment, whereas intraspecific identity affected fungal productivity to a similar extent under both nutrient treatments. Overall, there were no significant effects of intraspecific richness on plant and fungal productivity. Our findings suggest soil nutrient composition does not interact strongly with ECM intraspecific richness, at least under experimental conditions where mineral nutrients were not limiting. Under these conditions, intraspecific identity of ECM fungi becomes more important than richness in modulating plant and fungal performance.

Peran Information Conciousness dan Nutrient Information dalam Meningkatkan Kinerja Individual

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Niken Wahyu Wilujeng

2014-12-01

Full Text Available The objective of this research is to analyze nutrient information and information consciousness as factors that influence employee’s performance and job satisfication as intervening variable for finance employee in Brawijaya University. By employing Partial Least Square technique, it was indicated that nutrient information and information consciousness have positive effect to job satisfication, while job satisfication can also fully mediate nutrient information and information consciousness to employee’s performance. This research also indicated that information consciousness and nutrient information are factors that influence finance employee’s performance through intelectual emphasis.

Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays).

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Hu, Bo; Henry, Amelia; Brown, Kathleen M; Lynch, Jonathan P

2014-01-01

Formation of root cortical aerenchyma (RCA) can be induced by nutrient deficiency. In species adapted to aerobic soil conditions, this response is adaptive by reducing root maintenance requirements, thereby permitting greater soil exploration. One trade-off of RCA formation may be reduced radial transport of nutrients due to reduction in living cortical tissue. To test this hypothesis, radial nutrient transport in intact roots of maize (Zea mays) was investigated in two radiolabelling experiments employing genotypes with contrasting RCA. In the first experiment, time-course dynamics of phosphate loading into the xylem were measured from excised nodal roots that varied in RCA formation. In the second experiment, uptake of phosphate, calcium and sulphate was measured in seminal roots of intact young plants in which variation in RCA was induced by treatments altering ethylene action or genetic differences. In each of three paired genotype comparisons, the rate of phosphate exudation of high-RCA genotypes was significantly less than that of low-RCA genotypes. In the second experiment, radial nutrient transport of phosphate and calcium was negatively correlated with the extent of RCA for some genotypes. The results support the hypothesis that RCA can reduce radial transport of some nutrients in some genotypes, which could be an important trade-off of this trait.

Recovery of Nutrients from Biogas Digestate with Biochar and Clinoptilolite

DEFF Research Database (Denmark)

Kocatürk, Nazli Pelin

in recovery of nutrients whose natural reserves are being depleted such as phosphorus and potassium. In this thesis I propose the use of sorbents i.e. biochar and clinoptilolite to concentrate nutrients and subsequently the application of digestate-enriched biochar and clinoptilolite as fertiliser. Therefore...... the overall objective of this thesis is to investigate the use of clinoptilolite and biochar to recover plant nutrients from the liquid fraction of digestate resulting from anaerobic digestion of animal manure and investigate the plant-availability of the recovered form of nutrients. In Chapter 1 (General...... of nutrients on sorbent) but decreasing efficiencies of clinoptilolite to remove nutrients from the liquid fraction of digestate. In Chapter 3, I studied the chemical activation of biochar by treating the biochar with deionised water, hydrogen peroxide, sulfuric acid and sodium hydroxide solutions...

Predator-driven nutrient recycling in California stream ecosystems.

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Robin G Munshaw

Full Text Available Nutrient recycling by consumers in streams can influence ecosystem nutrient availability and the assemblage and growth of photoautotrophs. Stream fishes can play a large role in nutrient recycling, but contributions by other vertebrates to overall recycling rates remain poorly studied. In tributaries of the Pacific Northwest, coastal giant salamanders (Dicamptodon tenebrosus occur at high densities alongside steelhead trout (Oncorhynchus mykiss and are top aquatic predators. We surveyed the density and body size distributions of D. tenebrosus and O. mykiss in a California tributary stream, combined with a field study to determine mass-specific excretion rates of ammonium (N and total dissolved phosphorus (P for D. tenebrosus. We estimated O. mykiss excretion rates (N, P by bioenergetics using field-collected data on the nutrient composition of O. mykiss diets from the same system. Despite lower abundance, D. tenebrosus biomass was 2.5 times higher than O. mykiss. Mass-specific excretion summed over 170 m of stream revealed that O. mykiss recycle 1.7 times more N, and 1.2 times more P than D. tenebrosus, and had a higher N:P ratio (8.7 than that of D. tenebrosus (6.0, or the two species combined (7.5. Through simulated trade-offs in biomass, we estimate that shifts from salamander biomass toward fish biomass have the potential to ease nutrient limitation in forested tributary streams. These results suggest that natural and anthropogenic heterogeneity in the relative abundance of these vertebrates and variation in the uptake rates across river networks can affect broad-scale patterns of nutrient limitation.

Patterns of nutrient utilization. Implications for nitrogen metabolism

International Nuclear Information System (INIS)

Oldham, J.D.

1983-01-01

Nutrients react within both the rumen and the ruminant body, and the patterns of availability of different nutrients greatly influence their net utilization. In the rumen, microbial capture of N substrates, especially ammonia, depends on the degree of synchronization between rates of production of N substrates and of ATP to drive microbial protein synthesis. The form of dietary carbohydrate and of dietary N and the frequency of feeding can all affect the efficiency of microbial growth and digestion. The pattern of supply of nutrients to the body will also influence nutrient utilization. Disparities between diurnal patterns of supply of volatile fatty acids from the rumen and amino acids from the intestines will result in changes in balance of metabolic pathways. The balance between supply of glucogenic and lipogenic nutrients will influence efficiency of fattening. A major factor determining the pattern of utilization/metabolism of amino acids is the metabolic demand for protein synthesis, which varies with physiological state. (author)

Nutrient Concentrations and Stable Isotopes of Runoff from a Midwest Tile-Drained Corn Field

Science.gov (United States)

Wilkins, B. P.; Woo, D.; Li, J.; Michalski, G. M.; Kumar, P.; Conroy, J. L.; Keefer, D. A.; Keefer, L. L.; Hodson, T. O.

2017-12-01

Tile drains are a common crop drainage device used in Midwest agroecosystems. While efficient at drainage, the tiles provide a quick path for nutrient runoff, reducing the time available for microbes to use nutrients (e.g., NO3- and PO43-) and reduce export to riverine systems. Thus, understanding the effects of tile drains on nutrient runoff is critical to achieve nutrient reduction goals. Here we present isotopic and concentration data collected from tile drain runoff of a corn field located near Monticello, IL. Tile flow samples were measured for anion concentrations and stable isotopes of H2O and NO3-, while precipitation was measured for dual isotopes of H2O. Results demonstrate early tile flow from rain events have a low Cl- concentration (60% contribution) in the beginning of the hydrograph. As flow continues H2O isotopic values reflect pre-event water (ground and soil water), and Cl- concentrations increase representing a greater influence by matrix flow (60-90% contribution). Nitrate concentrations change dramatically, especially during the growing season, and do not follow a similar trend as the conservative Cl-, often decreasing days before, which represents missing nitrate in the upper surface portion of the soil. Nitrate isotopic data shows significant changes in 15N (4‰) and 18O (4‰) during individual hydrological events, representing that in addition to plant uptake and leaching, considerate NO3- is lost through denitrification. It is notable, that throughout the season d15N and d18O of nitrate change significantly representing that seasonally, substantial denitrification occurs.

A new tool for converting food frequency questionnaire data into nutrient and food group values: FETA research methods and availability.

Science.gov (United States)

Mulligan, Angela A; Luben, Robert N; Bhaniani, Amit; Parry-Smith, David J; O'Connor, Laura; Khawaja, Anthony P; Forouhi, Nita G; Khaw, Kay-Tee

2014-03-27

To describe the research methods for the development of a new open source, cross-platform tool which processes data from the European Prospective Investigation into Cancer and Nutrition Norfolk Food Frequency Questionnaire (EPIC-Norfolk FFQ). A further aim was to compare nutrient and food group values derived from the current tool (FETA, FFQ EPIC Tool for Analysis) with the previously validated but less accessible tool, CAFÉ (Compositional Analyses from Frequency Estimates). The effect of text matching on intake data was also investigated. Cross-sectional analysis of a prospective cohort study-EPIC-Norfolk. East England population (city of Norwich and its surrounding small towns and rural areas). Complete FFQ data from 11 250 men and 13 602 women (mean age 59 years; range 40-79 years). Nutrient and food group intakes derived from FETA and CAFÉ analyses of EPIC-Norfolk FFQ data. Nutrient outputs from FETA and CAFÉ were similar; mean (SD) energy intake from FETA was 9222 kJ (2633) in men, 8113 kJ (2296) in women, compared with CAFÉ intakes of 9175 kJ (2630) in men, 8091 kJ (2298) in women. The majority of differences resulted in one or less quintile change (98.7%). Only mean daily fruit and vegetable food group intakes were higher in women than in men (278 vs 212 and 284 vs 255 g, respectively). Quintile changes were evident for all nutrients, with the exception of alcohol, when text matching was not executed; however, only the cereals food group was affected. FETA produces similar nutrient and food group values to the previously validated CAFÉ but has the advantages of being open source, cross-platform and complete with a data-entry form directly compatible with the software. The tool will facilitate research using the EPIC-Norfolk FFQ, and can be customised for different study populations.

The Nutrient Density of Snacks: A Comparison of Nutrient Profiles of Popular Snack Foods Using the Nutrient-Rich Foods Index.

Science.gov (United States)

Hess, Julie; Rao, Goutham; Slavin, Joanne

2017-01-01

Background: Although Americans receive almost a quarter of their daily energy from snacks, snacking remains a poorly defined and understood eating occasion. However, there is little dietary guidance about choosing snacks. Families, clinicians, and researchers need a comprehensive approach to assessing their nutritional value. Objective: To quantify and compare the nutrient density of commonly consumed snacks by their overall nutrient profiles using the Nutrient-Rich Foods (NRF) Index 10.3. Methods: NRF Index scores were calculated for the top 3 selling products (based on 2014 market research data) in different snack categories. These NRF scores were averaged to provide an overall nutrient-density score for each category. Results: Based on NRF scores, yogurt (55.3), milk (52.5), and fruit (30.1) emerged as the most nutrient-dense snacks. Ice cream (-4.4), pies and cakes (-11.1), and carbonated soft drinks (-17.2) emerged as the most nutrient-poor snacks. Conclusions: The NRF Index is a useful tool for assessing the overall nutritional value of snacks based on nutrients to limit and nutrients to encourage.

The contribution of leaching to the rapid release of nutrients and carbon in the early decay of wetland vegetation

Science.gov (United States)

Davis, S. E.; Childers, D.L.; Noe, G.B.

2006-01-01

Our goal was to quantify the coupled process of litter turnover and leaching as a source of nutrients and fixed carbon in oligotrophic, nutrient-limited wetlands. We conducted poisoned and non-poisoned incubations of leaf material from four different perennial wetland plants (Eleocharis spp., Cladium jamaicense, Rhizophora mangle and Spartina alterniflora) collected from different oligotrophic freshwater and estuarine wetland settings. Total phosphorus (TP) release from the P-limited Everglades plant species (Eleocharis spp., C. jamaicense and R. mangle) was much lower than TP release by the salt marsh plant S. alterniflora from N-limited North Inlet (SC). For most species and sampling times, total organic carbon (TOC) and TP leaching losses were much greater in poisoned than non-poisoned treatments, likely as a result of epiphytic microbial activity. Therefore, a substantial portion of the C and P leached from these wetland plant species was bio-available to microbial communities. Even the microbes associated with S. alterniflora from N-limited North Inlet showed indications of P-limitation early in the leaching process, as P was removed from the water column. Leaves of R. mangle released much more TOC per gram of litter than the other species, likely contributing to the greater waterborne [DOC] observed by others in the mangrove ecotone of Everglades National Park. Between the two freshwater Everglades plants, C. jamaicense leached nearly twice as much P than Eleocharis spp. In scaling this to the landscape level, our observed leaching losses combined with higher litter production of C. jamaicense compared to Eleocharis spp. resulted in a substantially greater P leaching from plant litter to the water column and epiphytic microbes. In conclusion, leaching of fresh plant litter can be an important autochthonous source of nutrients in freshwater and estuarine wetland ecosystems. ?? Springer 2006.

Nutrient availability affects pigment production but not growth in lichens of biological soil crusts

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Bowker, M.A.; Koch, G.W.; Belnap, J.; Johnson, N.C.

2008-01-01

Recent research suggests that micronutrients such as Mn may limit growth of slow-growing biological soil crusts (BSCs) in some of the drylands of the world. These soil surface communities contribute strongly to arid ecosystem function and are easily degraded, creating a need for new restoration tools. The possibility that Mn fertilization could be used as a restoration tool for BSCs has not been tested previously. We used microcosms in a controlled greenhouse setting to investigate the hypothesis that Mn may limit photosynthesis and consequently growth in Collema tenax, a dominant N-fixing lichen found in BSCs worldwide. We found no evidence to support our hypothesis; furthermore, addition of other nutrients (primarily P, K, and Zn) had a suppressive effect on gross photosynthesis (P = 0.05). We also monitored the growth and physiological status of our microcosms and found that other nutrients increased the production of scytonemin, an important sunscreen pigment, but only when not added with Mn (P = 0.01). A structural equation model indicated that this effect was independent of any photosynthesis-related variable. We propose two alternative hypotheses to account for this pattern: (1) Mn suppresses processes needed to produce scytonemin; and (2) Mn is required to suppress scytonemin production at low light, when it is an unnecessary photosynthate sink. Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally stressful periods due to modification of scytonemin production. Thus, Mn enrichment should be studied further for its potential to facilitate BSC rehabilitation. ?? 2008 Elsevier Ltd.

Isotope technology as applied to studies of soil fertility, nutrient availability and fertilizer use on flooded rice soils

International Nuclear Information System (INIS)

Patnaik, S.; Mohanty, S.K.; Dash, R.N.

1979-01-01

Research is reviewed on soil fertility and nutrient availability in relation to fertilizer efficiency, especially o stimulated the mineralization of soil N. Losses of added N from oxidation, leaching, denitrification and volatilization could be minimized through placement of N fertilizer in the reduced zone or by the addition of rice straw for rapid immobilization of added N. Fe-P and, to some extent, Al-P provided P to the rice plants, particularly in P-deficient soils. Added phosphates were converted to these forms which, under waterlogged soil conditions, released more P into the soil solution through reductive solubilization of Fe-P and hydrolytic dissolution of Al-P. The rice plants generally absorbed fertilizer N during the vegetative growth period and N mineralized from soil organic matter during the reproductive growth period. 15 N studies indicated higher grain yield and utilization of applied N through fractional application of 70-80% during the vegetative growth period, and the remaining 20-30% top-dressed at the panicle initiation stage. Ammonia-containing and -forming (urea) fertilizers were superior to the nitrate form of N. In field tests, however, the crop recovery of applied N was relatively low. Phosphatic fertilizers were best applied at puddling. In general, water-soluble phosphates were superior to citrate-soluble or insoluble phosphates. The latter could be made as efficient as the water-soluble phosphate, at comparable low rates, by applying to the moist aerobic acid soil 2-3 weeks before flooding and transplanting rice. Tracer studies have been used to evaluate the nutrient-supplying capacity of the soil from the 'A' value concept. 'A' values varied with varying conditions of soil, rate, time and form of fertilizer application. Zn nutrition of the rice plant and fertilizer use with 65 Zn have been studied relatively little. Some lines of future work are suggested

Response of tropical peat swamp forest tree species seedlings to macro nutrients

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Tri Wira Yuwati

2015-10-01

Full Text Available Abstract Efforts of restoration of degraded tropical peat swamp forest were facing constraints due to the low available nutrient level of peat. The transplanted peat swamp forest species seedlings experienced low survival rate and poor growth performance. This study aimed to demonstrate the response of ten tropical peat swamp forest species seedlings whether climax and pioneer species to macro-nutrients addition in the nursery. The growth performance of climax and pioneer tropical peat swamp species seedlings was recorded following addition of macro nutrients of Nitrogen (N, Phosphorus(P, Potassium(K and Dolomitic limestone (CaMg. The result showed that Alstonia spatulata and Parartocarpus venenosus showed positive growth response following macro nutrients addition. This study concluded that tropical peat swamp pioneer species has lower necessity for macro-nutrients addition than tropical peat swamp climax species.

Hyperspectral remote sensing techniques for grass nutrient estimations in savannah ecosystems

CSIR Research Space (South Africa)

Ramoelo, Abel

2010-03-01

Full Text Available Information on the distribution of grass quality (nutrient concentration) is crucial in understanding rangeland vitality and facilitates effective management of wildlife and livestock. The spatial distribution of grass nutrient concentration occurs...

Exponential Nutrient Loading as a Means to Optimize Bareroot Nursery Fertility of Oak Species

Science.gov (United States)

Zonda K. D. Birge; Douglass F. Jacobs; Francis K. Salifu

2006-01-01

Conventional fertilization in nursery culture of hardwoods may involve supply of equal fertilizer doses at regularly spaced intervals during the growing season, which may create a surplus of available nutrients in the beginning and a deficiency in nutrient availability by the end of the growing season. A method of fertilization termed “exponential nutrient loading” has...

Characterization of biochars from different sources and evaluation of release of nutrients and contaminants

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Natália Aragão de Figueredo

Full Text Available ABSTRACT The biochar, product of pyrolysis of organic waste, has been used as a soil conditioner and alternative on solid waste management. However, the raw material and pyrolysis temperature used influence the quantity and dynamics of release of nutrients and contaminants from the biochar. The objective was to evaluate the use of waste sugarcane bagasse, eucalyptus and sewage sludge for production of biochar and determine the chemical, physical, mineralogical properties and acid extraction of these materials produced at 350 °C and 500 °C. Were evaluated the proportion of C, H, N, O; ashes; macro and micronutrients, plus some contaminants; characterization of mineral phases by diffractometry of X- rays; functional groups by infrared absorption spectroscopy (FTIR. Moreover, it was determined the release of nutrients and contaminants for the extraction in increasing concentration of HNO3 (0,01 - 2,0 mol L-1. The O/C and H/C relations decreased with increasing temperature of pyrolysis, which define a greater stability of the C of biochars. Sewage sludge biochar (BC-L had the highest nutrient release rates and contaminant metals (Cd, Cr, Ni and Pb. Acid extraction of other biochars was very low (<20% of the total content. The results indicate that the carbon fraction of biochar contributes to the low rate of release of the elements in acid place.

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia

International Nuclear Information System (INIS)

Wulp, Simon A. van der; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J.

2016-01-01

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377 m 3 s −1 entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174 tons and 14 to 60 tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics. - Highlights: • Full overview of river discharges, nutrient flux and nutrient levels in Jakarta Bay • Important overview of nutrient flux from individual rivers • Simulations identify the principal drivers of water circulation and nutrient gradient. • Nutrient dispersion model includes the local effects of the Java Sea current system.

Relationship of carbohydrates and lignin molecular structure spectral profiles to nutrient profile in newly developed oats cultivars and barley grain

Science.gov (United States)

Prates, Luciana Louzada; Refat, Basim; Lei, Yaogeng; Louzada-Prates, Mariana; Yu, Peiqiang

2018-01-01

The objectives of this study were to quantify the chemical profile and the magnitude of differences in the oat and barley grain varieties developed by Crop Development Centre (CDC) in terms of Cornell Net Carbohydrate Protein System (CNCPS) carbohydrate sub-fractions: CA4 (sugars), CB1 (starch), CB2 (soluble fibre), CB3 (available neutral detergent fibre - NDF), and CC (unavailable carbohydrate); to estimate the energy values; to detect the lignin and carbohydrate (CHO) molecular structure profiles in CDC Nasser and CDC Seabiscuit oat and CDC Meredith barley grains by using Fourier transform infrared attenuated total reflectance (FTIR-ATR); to develop a model to predict nutrient supply based on CHO molecular profile. Results showed that NDF, ADF and CHO were greater (P 0.05) for oat and barley grains as well as non-structural CHO. However, cellulosic compounds peak area and height were greater (P < 0.05) in oat than barley grains. Multiple regressions were determined to predict nutrient supply by using lignin and CHO molecular profiles. It was concluded that although there were some differences between oat and barley grains, CDC Nasser and CDC Meredith presented similarities related to chemical and molecular profiles, indicating that CDC Meredith barley could be replaced for CDC Nasser as ruminant feed. The FTIR was able to identify functional groups related to CHO molecular spectral in oat and barley grains and FTIR-ATR results could be used to predict nutrient supply in ruminant livestock systems.

Nutrient balances in the forest energy cycle

International Nuclear Information System (INIS)

Olsson, Bengt

2006-02-01

or wood in fuel mixture). Losses of P at harvesting, fuel storage or transportation, and contamination (soil) or additions of lime are possible causes. To a less extent, also K losses seem to occur in the process. On average, the recommended highest dose of ash to forest (3000 kg d.w./ha) over-compensate for alkalinity but under-compensate for K and P. There is thus a risk that standard values of ash doses will not result in the target compensation, in particular if the aim is to compensate for specific elements. The nutrient compensation needs can be defined to two levels (compensate for slash, or for slash and stem harvesting, respectively), and to four aims: (1) improve forest tree nutrient status and growth, (2) increase base saturation of forest soils and increase soil nutrient pools, (3) increase alkalinity in run-off water to counteract acidification of surface waters, and (4) as a complement to nitrogen fertilisation. Increasing the alkalinity of soils and soil water is the aim that can be most easily reached by ash application, due to the relatively high Ca and Mg contents in ashes. Compensation of ash for K losses is complicated by the high mobility of K ion in ecosystems and because its high solubility even in stabilised ashes. K in logging residues and ashes tend to be leached out and lost. Management for maintaining high availability of K in forest ecosystems should include several aspects, in particular the de sign of clear-fellings, timing of ash recycling and handling of slash and ashes. Compensation for P by application of stabilised wood-ashes is normally in efficient in the short time perspective, due to low P content in ashes and the bonding of P into poorly soluble apatite. However, in the long run P in ashes may improve forest P nutrition. New research is needed to estimate P-fluxes associated with harvesting, storage and transport of forest biomass in realistic situations, and to evaluate if P availability will be deteriorated in the long run

Nutrient cycling in a RRIM 600 clone rubber plantation

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Murbach Marcos Roberto

2003-01-01

Full Text Available Few reports have been presented on nutrient cycling in rubber tree plantations (Hevea brasiliensis Muell. Arg.. This experiment was carried out to evaluate: the effect of K rates on the amount of nutrients transfered to the soil in a 13-year old Hevea brasilensis RRIM 600 clone plantation, nutrient retranslocation from the leaves before falling to the soil, and nutrient loss by dry rubber export. The experiment started in 1998 and potassium was applied at the rates of 0, 40, 80 and 160 kg ha-1 of K2O under the crowns of 40 rubber trees of each plot. Literfall collectors, five per plot, were randomly distributed within the plots under the trees. The accumulated literfall was collected monthly during one year. The coagulated rubber latex from each plot was weighed, and samples were analyzed for nutrient content. Increasing K fertilization rates also increased the K content in leaf literfall. Calcium and N were the most recycled leaf nutrients to the soil via litterfall. Potassium, followed by P were the nutrients with the highest retranslocation rates. Potassium was the most exported nutrient by the harvested rubber, and this amount was higher than that transfered to the soil by the leaf literfall.

Approaches and uncertainties in nutrient budgets; Implications for nutrient management and environmental policies

NARCIS (Netherlands)

Oenema, O.; Kros, J.; Vries, de W.

2003-01-01

Nutrient budgets of agroecosystems are constructed either (i) to increase the understanding of nutrient cycling, (ii) as performance indicator and awareness raiser in nutrient management and environmental policy, or (iii) as regulating policy instrument to enforce a certain nutrient management

Nutrients affecting brain composition and behavior

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Wurtman, R. J.

1987-01-01

This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

Above-ground woody biomass allocation and within tree carbon and nutrient distribution of wild cherry (Prunus avium L. – a case study

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Christopher Morhart

2016-02-01

Full Text Available Background: The global search for new ways to sequester carbon has already reached agricultural lands. Such land constitutes a major potential carbon sink. The production of high value timber within agroforestry systems can facilitate an in-situ carbon storage function. This is followed by a potential long term ex- situ carbon sinkwithin long lasting products such as veneer and furniture. For this purpose wild cherry (Prunus avium L. is an interesting option for middle Europe, yielding high prices on the timber market. Methods: A total number of 39 wild cherry were sampled in 2012 and 2013 to assess the leafless above ground biomass. The complete trees including stem and branches were separated into 1 cm diameter classes. Wood and bark from sub-samples were analysed separately and nutrient content was derived. Models for biomass estimation were constructed for all tree compartments. Results: The smallest diameter classes possess the highest proportion of bark due to smaller cross sectional area. Tree boles with a greater amount of stem wood above 10 cm in diameter will have a more constant bark proportion. Total branch bark proportion also remains relatively constant above d1.3m measurements of 8 cm. A balance is evident between the production of new branches with a low diameter and high bark proportion offset by the thickening and a relative reduction in bark proportion in larger branches. The results show that a single tree with an age of 17 and 18 years can store up to 85 kg of carbon within the aboveground biomass portion, an amount that will increase as the tree matures. Branches display greater nutrient content than stem sections per volume unit which can be attributed to a greater bark proportion. Conclusions: Using the derived models the carbon and the nutrient content of above-ground woody biomass of whole trees can be calculated. Suggested values for carbon with other major and minor nutrients held within relatively immature trees

Performance test of nutrient control equipment for hydroponic plants

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Rahman, Nurhaidar; Kuala, S. I.; Tribowo, R. I.; Anggara, C. E. W.; Susanti, N. D.

2017-11-01

Automatic control equipment has been made for the nutrient content in irrigation water for hydroponic plants. Automatic control equipment with CCT53200E conductivity controller to nutrient content in irrigation water for hydroponic plants, can be used to control the amount of TDS of nutrient solution in the range of TDS numbers that can be set according to the range of TDS requirements for the growth of hydroponically cultivated crops. This equipment can minimize the work time of hydroponic crop cultivators. The equipment measurement range is set between 1260 ppm up to 1610 ppm for spinach plants. Caisim plants were included in this experiment along with spinach plants with a spinach plants TDS range. The average of TDS device is 1450 ppm, while manual (conventional) is 1610 ppm. Nutrient solution in TDS controller has pH 5,5 and temperature 29,2 °C, while manual is pH 5,6 and temperature 31,3 °C. Manually treatment to hydroponic plant crop, yields in an average of 39.6 grams/plant, greater than the yield of spinach plants with TDS control equipment, which is in an average of 24.6 grams / plant. The yield of caisim plants by manual treatment is in an average of 32.3 grams/crop, less than caisim crop yields with TDS control equipment, which is in an average of 49.4 grams/plant.

Nutrient budgets for large Chinese estuaries

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S. M. Liu

2009-10-01

Full Text Available Chinese rivers deliver about 5–10% of global freshwater input and 15–20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN and depleted in dissolved inorganic phosphate (PO₄³⁻ with very high DIN: PO₄³⁻ concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3–4 times higher than those in the winter with the exception of NH₄⁺. The flux of NH₄⁺ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ~4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea. This suggests that land-derived nutrients are largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and

Morphology-dependent water budgets and nutrient fluxes in arctic thaw ponds

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Koch, Joshua C.; Gurney, Kirsty; Wipfli, Mark S.

2014-01-01

Thaw ponds on the Arctic Coastal Plain of Alaska are productive ecosystems, providing habitat and food resources for many fish and bird species. Permafrost in this region creates unique pond morphologies: deep troughs, shallow low-centred polygons (LCPs) and larger coalescent ponds. By monitoring seasonal trends in pond volume and chemistry, we evaluated whether pond morphology and size affect water temperature and desiccation, and nitrogen (N) and phosphorus (P) fluxes. Evaporation was the largest early-summer water flux in all pond types. LCPs dried quickly and displayed high early-summer nutrient concentrations and losses. Troughs consistently received solute-rich subsurface inflows, which accounted for 12 to 42 per cent of their volume and may explain higher P in the troughs. N to P ratios increased and ammonium concentrations decreased with pond volume, suggesting that P and inorganic N availability may limit ecosystem productivity in older, larger ponds. Arctic summer temperatures will likely increase in the future, which may accelerate mid-summer desiccation. Given their morphology, troughs may remain wet, become warmer and derive greater nutrient loads from their thawing banks. Overall, seasonal- to decadal-scale warming may increase ecosystem productivity in troughs relative to other Arctic Coastal Plain ponds. 

Economic benefits of combining soil and water conservation measures with nutrient management in semiarid Burkina Faso

NARCIS (Netherlands)

Zougmoré, R.; Mando, A.; Stroosnijder, L.; Ouédraogo, E.

2004-01-01

Nutrient limitation is the main cause of per capita decline in crop production in the Sahel, where water shortage also limits an efficient use of available nutrients. Combining soil and water conservation measures with locally available nutrient inputs may optimize crop production and economic

Simultaneous bilateral isolated greater trochanter fracture

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Maruti Kambali

2013-01-01

Full Text Available A 48-year-old woman sustained simultaneous isolated bilateral greater trochanteric fracture, following a road traffic accident. The patient presented to us 1 month after the injury. She presented with complaints of pain in the left hip and inability to walk. Roentgenograms revealed displaced comminuted bilateral greater trochanter fractures. The fracture of the left greater trochanter was reduced and fixed internally using the tension band wiring technique. The greater trochanter fracture on the right side was asymptomatic and was managed conservatively. The patient regained full range of motion and use of her hips after a postoperative follow-up of 6 months. Isolated fractures of the greater trochanter are unusual injuries. Because of their relative rarity and the unsettled controversy regarding their etiology and pathogenesis, several methods of treatment have been advocated. Furthermore, the reports of this particular type of injury are not plentiful and the average textbook coverage afforded to this entity is limited. In our study we discuss the mechanism of injury and the various treatment options available.

Assessing Nutrient Intake and Nutrient Status of HIV Seropositive Patients Attending Clinic at Chulaimbo Sub-District Hospital, Kenya

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Agatha Christine Onyango

2012-01-01

Full Text Available Background. Nutritional status is an important determinant of HIV outcomes. Objective. To assess the nutrient intake and nutrient status of HIV seropositive patients attending an AIDS outpatient clinic, to improve the nutritional management of HIV-infected patients. Design. Prospective cohort study. Setting. Comprehensive care clinic in Chulaimbo Sub-District Hospital, Kenya. Subjects. 497 HIV sero-positive adults attending the clinic. Main Outcome Measures. Evaluation of nutrient intake using 24-hour recall, food frequency checklist, and nutrient status using biochemical assessment indicators (haemoglobin, creatinine, serum glutamate pyruvate (SGPT and mean corpuscular volume (MCV. Results. Among the 497 patients recruited (M : F sex ratio: 1.4, mean age: 39 years ± 10.5 y, Generally there was inadequate nutrient intake reported among the HIV patients, except iron (10.49 ± 3.49 mg. All the biochemical assessment indicators were within normal range except for haemoglobin 11.2 g/dL (11.4 ± 2.60 male and 11.2 ± 4.25 female. Conclusions. Given its high frequency, malnutrition should be prevented, detected, monitored, and treated from the early stages of HIV infection among patients attending AIDS clinics in order to improve survival and quality of life.

Frequent Canned Food Use is Positively Associated with Nutrient-Dense Food Group Consumption and Higher Nutrient Intakes in US Children and Adults

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Kevin B. Comerford

2015-07-01

Full Text Available In addition to fresh foods, many canned foods also provide nutrient-dense dietary options, often at a lower price, with longer storage potential. The aim of this study was to compare nutrient-dense food group intake and nutrient intake between different levels of canned food consumption in the US. Consumption data were collected for this cross-sectional study from 9761 American canned food consumers (aged two years and older from The NPD Group’s National Eating Trends® (NET® database during 2011–2013; and the data were assessed using The NPD Group’s Nutrient Intake Database. Canned food consumers were placed into three groups: Frequent Can Users (≥6 canned items/week; n = 2584, Average Can Users (3–5 canned items/week; n = 4445, and Infrequent Can Users (≤2 canned items/week; n = 2732. The results provide evidence that Frequent Can Users consume more nutrient-dense food groups such as fruits, vegetables, dairy products, and protein-rich foods, and also have higher intakes of 17 essential nutrients including the shortfall nutrients—potassium, calcium and fiber—when compared to Infrequent Can Users. Therefore, in addition to fresh foods, diets higher in nutrient-dense canned food consumption can also offer dietary options which improve nutrient intakes and the overall diet quality of Americans.

Modeling farm nutrient flows in the North China Plain to reduce nutrient losses

NARCIS (Netherlands)

Zhao, Zhanqing; Bai, Zhaohai; Wei, Sha; Ma, Wenqi; Wang, Mengru; Kroeze, Carolien; Ma, Lin

2017-01-01

Years of poor nutrient management practices in the agriculture industry in the North China Plain have led to large losses of nutrients to the environment, causing severe ecological consequences. Analyzing farm nutrient flows is urgently needed in order to reduce nutrient losses. A farm-level

Nutrient limitation of soil microbial activity during the earliest stages of ecosystem development.

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Castle, Sarah C; Sullivan, Benjamin W; Knelman, Joseph; Hood, Eran; Nemergut, Diana R; Schmidt, Steven K; Cleveland, Cory C

2017-11-01

A dominant paradigm in ecology is that plants are limited by nitrogen (N) during primary succession. Whether generalizable patterns of nutrient limitation are also applicable to metabolically and phylogenetically diverse soil microbial communities, however, is not well understood. We investigated if measures of N and phosphorus (P) pools inform our understanding of the nutrient(s) most limiting to soil microbial community activities during primary succession. We evaluated soil biogeochemical properties and microbial processes using two complementary methodological approaches-a nutrient addition microcosm experiment and extracellular enzyme assays-to assess microbial nutrient limitation across three actively retreating glacial chronosequences. Microbial respiratory responses in the microcosm experiment provided evidence for N, P and N/P co-limitation at Easton Glacier, Washington, USA, Puca Glacier, Peru, and Mendenhall Glacier, Alaska, USA, respectively, and patterns of nutrient limitation generally reflected site-level differences in soil nutrient availability. The activities of three key extracellular enzymes known to vary with soil N and P availability developed in broadly similar ways among sites, increasing with succession and consistently correlating with changes in soil total N pools. Together, our findings demonstrate that during the earliest stages of soil development, microbial nutrient limitation and activity generally reflect soil nutrient supply, a result that is broadly consistent with biogeochemical theory.

The management of nutrients and water in the west African semi-arid tropics

International Nuclear Information System (INIS)

Bationo, A.; Bielders, C.L.; Duivenbooden, N. van; Buerkert, A.C.; Seyni, F.

1998-01-01

At present, the farming systems in the west African semi-arid tropics are unsustainable, low in productivity, and destructive to the environment. A striking feature of the soils is their inherently low fertility, with negative plant-nutrient balance in many cropping systems. Research in N-use efficiency (NUE) indicated that calcium ammonium nitrate (CAN) significantly outperformed urea on millet. Fertilizer losses, greater for urea (53%) than for CAN (25%) were believed to be due to ammonia volatilization. Continuous cropping resulted in lower yields compared to a cereal grown after cowpea or groundnut, and NUE was improved with crop rotation. Phosphorus deficiency is a major constraint. Phosphate rock (PR), indigenous to the region, e.g. at Tahoua in Niger and Tilemsi in Mali, is suitable for direct application. Partial acidulation of low-solubility PR improves agronomic effectiveness. Long-term soil-fertility management trials indicate that although application of mineral fertilizers increase yields, they alone cannot sustain productivity. When mineral fertilizers are combined with other technologies, such as the return of crop residues and manure, productive and sustainable production systems are possible. Water-use efficiency increased dramatically with the addition of plant nutrients. Technologies for land surface management and water harvesting, and appropriate cropping systems with careful varietal selection all contribute to the optimization of soil-water use. Future research should focus on water and nutrient interactions and on understanding why presently available improved technologies are not adopted by farmers even when using a participatory approach. (author)

Microbial enzyme activity, nutrient uptake and nutrient limitation in forested streams

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Brian H. Hill; Frank H. McCormick; Bret C. Harvey; Sherri L. Johnson; Melvin L. Warren; Colleen M. Elonen

2010-01-01

The flow of organic matter and nutrients from catchments into the streams draining them and the biogeochemical transformations of organic matter and nutrients along flow paths are fundamental processes instreams (Hynes,1975; Fisher, Sponseller & Heffernan, 2004). Microbial biofilms are often the primary interface for organic matter and nutrient uptake and...

Nutrients for the aging eye

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Rasmussen HM

2013-06-01

Full Text Available Helen M Rasmussen,1 Elizabeth J Johnson2 1Educational Studies, Lesley University, Cambridge, MA, USA; 2Carotenoid and Health Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA Abstract: The incidence of age-related eye diseases is expected to rise with the aging of the population. Oxidation and inflammation are implicated in the etiology of these diseases. There is evidence that dietary antioxidants and anti-inflammatories may provide benefit in decreasing the risk of age-related eye disease. Nutrients of interest are vitamins C and E, β-carotene, zinc, lutein, zeaxanthin, and the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid. While a recent survey finds that among the baby boomers (45–65 years old, vision is the most important of the five senses, well over half of those surveyed were not aware of the important nutrients that play a key role in eye health. This is evident from a national survey that finds that intake of these key nutrients from dietary sources is below the recommendations or guidelines. Therefore, it is important to educate this population and to create an awareness of the nutrients and foods of particular interest in the prevention of age-related eye disease. Keywords: nutrition, aging, eye health

Treated Olive Cake as a Non-forage Fiber Source for Growing Awassi Lambs: Effects on Nutrient Intake, Rumen and Urine pH, Performance, and Carcass Yield

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M. S. Awawdeh

2013-05-01

Full Text Available The objective of this study was to investigate the effects of partial replacement of wheat hay with sun-dried (SOC or acid-treated SOC (ASOC olive cake on nutrient intake and performance of Awassi lambs. An additional objective was to study the effects of acid treatment of olive cake (OC on its chemical composition and nutritive value. On DM basis, sun-drying of OC did not dramatically affect its chemical composition. On the other hand, treating SOC with phosphoric acid decreased (p<0.05 SOC contents of neutral detergent fiber. Twenty seven male lambs (17.6±0.75 kg body weight individually housed in shaded pens were randomly assigned to one of three dietary treatments (9 lambs/treatment. Dietary treatments were formulated to be isocaloric and isonitrogenous by replacing 50% of wheat hay in the control diet (CTL with SOC or ASOC and to meet all nutrient requirements. Dietary treatments had no effects on nutrient intake or digestibility except for ether extract. Lambs fed the SOC diet had (p = 0.05 faster growth rate, greater final body weight, and greater total body weight gain in comparison with the CTL diet, but not different from the ASOC diet. Additionally, lambs fed the SOC diet had greater (p = 0.03 hot and cold carcass weights than the ASOC diet, but not different from the CTL diet. However, feed conversion ratios and dressing percentages were similar among dietary treatments. In conclusion, replacing half of dietary wheat hay with SOC improved performance of Awassi lambs with no detrimental effects on nutrients intake or digestibility. No further improvements in the nutritive value of SOC and lambs performance were detected when SOC was treated with acid.

Impacts of post-harvest slash and live-tree retention on biomass and nutrient stocks in Populus tremuloides Michx.-dominated forests, northern Minnesota, USA

Science.gov (United States)

Klockow, Paul A.; D'Amato, Anthony W.; Bradford, John B.

2013-01-01

Globally, there is widespread interest in using forest-derived biomass as a source of bioenergy. While conventional timber harvesting generally removes only merchantable tree boles, harvesting biomass feedstock can remove all forms of woody biomass (i.e., live and dead standing woody vegetation, downed woody debris, and stumps) resulting in a greater loss of biomass and nutrients as well as more severe habitat alteration. To investigate the potential impacts of this practice, this study examined the initial impacts (pre- and post-harvest) of various levels of slash and live-tree retention on biomass and nutrient stocks, including carbon (C), nitrogen (N), calcium (Ca), potassium (K), and phosphorus (P), in Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Treatments examined included three levels of slash retention, whole-tree harvest (WTH), 20% slash retention (20SR), and stem-only harvest (SOH), factored with three levels of green-tree retention, no trees retained (NONE), dispersed retention (DISP), and aggregate retention (AGR). Slash retention was the primary factor affecting post-harvest biomass and nutrient stocks, including woody debris pools. Compared to the unharvested control, stocks of biomass, carbon, and nutrients, including N, Ca, K, and P, in woody debris were higher in all treatments. Stem-only harvests typically contained greater biomass and nutrient stocks than WTH, although biomass and nutrients within 20SR, a level recommended by biomass harvesting guidelines in the US and worldwide, generally did not differ from WTH or SOH. Biomass in smaller-diameter slash material (typically 2.5-22.5 cm in diameter) dominated the woody debris pool following harvest regardless of slash retention level. Trends among treatments in this diameter range were generally similar to those in the total woody debris pool. Specifically, SOH contained significantly greater amounts of biomass than WTH while 20SR was not different from either WTH or

Agronomic Characteristics Related to Grain Yield and Nutrient Use Efficiency for Wheat Production in China.

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Limin Chuan

Full Text Available In order to make clear the recent status and trend of wheat (Triticum aestivum L. production in China, datasets from multiple field experiments and published literature were collected to study the agronomic characteristics related to grain yield, fertilizer application and nutrient use efficiency from the year 2000 to 2011. The results showed that the mean grain yield of wheat in 2000-2011 was 5950 kg/ha, while the N, P2O5 and K2O application rates were 172, 102 and 91 kg/ha on average, respectively. The decrease in N and P2O5 and increase in K2O balanced the nutrient supply and was the main reason for yield increase. The partial factor productivity (PFP, kg grain yield produced per unit of N, P2O5 or K2O applied values of N (PFP-N, P (PFP-P and K (PFP-K were in the ranges of 29.5~39.6, 43.4~74.9 and 44.1~76.5 kg/kg, respectively. While PFP-N showed no significant changes from 2000 to 2010, both PFP-P and PFP-K showed an increased trend over this period. The mean agronomic efficiency (AE, kg grain yield increased per unit of N, P2O5 or K2O applied values of N (AEN, P (AEP and K (AEK were 9.4, 10.2 and 6.5 kg/kg, respectively. The AE values demonstrated marked inter-annual fluctuations, with the amplitude of fluctuation for AEN greater than those for AEP and AEK. The mean fertilizer recovery efficiency (RE, the fraction of nutrient uptake in aboveground plant dry matter to the nutrient of fertilizer application values of N, P and K in the aboveground biomass were 33.1%, 24.3% and 28.4%, respectively. It was also revealed that different wheat ecological regions differ greatly in wheat productivity, fertilizer application and nutrient use efficiency. In summary, it was suggested that best nutrient management practices, i.e. fertilizer recommendation applied based on soil testing or yield response, with strategies to match the nutrient input with realistic yield and demand, or provided with the 4R's nutrient management (right time, right rate, right

Soil Nutrient Stocks in Sub-Saharan Africa: Modeling Soil Nutrients Using Machine Learning

Science.gov (United States)

Cooper, M. W.; Hengl, T.; Shepherd, K.; Heuvelink, G. B. M.

2017-12-01

We present the results of our work modeling 15 target soil nutrients at 250 meter resolution across Sub-Saharan Africa. We used a large stack of GIS layers as covariates, including layers on topography, climate, geology, hydrology and land cover. As training data we used ca. 59,000 soil samples harmonized across a number of projects and datasets, and we modeled each nutrient using an ensemble of random forest and gradient boosting algorithms, implemented using the R packages ranger and xgboost. Using cross validation, we determined that significant models can be produced for organic Carbon, total (organic) Nitrogen, total Phosphorus, and extractable Phosphorous, Potassium, Calcium, Magnesium, Sulfur, Sodium, Iron, Manganese, Zinc, Copper, Aluminum and Boron, with an R-square value between 40 and 95%. The main covariates explaining spatial distribution of nutrients were precipitation and land form parameters. However, we were unable to significantly predict Sulfur, Phosphorus and Boron as these could not be correlated with any environmental covariates we used. Although the accuracy of predictions looks promising, our predictions likely suffer from the significant spatial clustering of the sampling locations, as well as a lack of more detailed data on geology and parent material at a continental scale. These results will contribute to targeting agricultural investments and interventions, as well as targeting restoration efforts and estimating yield potential and yield gaps. These results were recently published in the journal Nutrient Cycling in Agroecosystems (DOI: 10.1007/s10705-017-9870-x) and the maps are available for download under the ODC Open Database License.

Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River

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Houser, Jeff N.; Giblin, Shawn M.; James, William F.; Langrehr, H.A.; Rogala, James T.; Sullivan, John F.; Gray, Brian R.

2013-01-01

River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi River (UMR) that varied in connectivity to the channel. Greater connectivity was associated with higher water column nitrate (NO3-N) concentration, higher rates of sediment phosphorus (P) release, and higher rates of NO3-N flux to the sediments. Rates of sediment P and N (as NH4-N) release were similar to those of eutrophic lakes. Water column nutrient concentrations were high, and FFP tissue was nutrient rich suggesting that the eutrophic condition of the UMR often facilitated abundant FFP. However, tissue nutrient concentrations, and the associations between FFP biomass and water column nutrient concentrations, suggested that nutrients constrained FFP abundance at some sites. FFP abundance was positively associated with SAV abundance and negatively associated with dissolved oxygen concentration. These results illustrate important connections among hydraulic connectivity, nutrient cycling, FFP, SAV, and DO in the backwaters of a large, floodplain river.

Organic foods contain higher levels of certain nutrients, lower levels of pesticides, and may provide health benefits for the consumer.

Science.gov (United States)

Crinnion, Walter J

2010-04-01

The multi-billion dollar organic food industry is fueled by consumer perception that organic food is healthier (greater nutritional value and fewer toxic chemicals). Studies of the nutrient content in organic foods vary in results due to differences in the ground cover and maturity of the organic farming operation. Nutrient content also varies from farmer to farmer and year to year. However, reviews of multiple studies show that organic varieties do provide significantly greater levels of vitamin C, iron, magnesium, and phosphorus than non-organic varieties of the same foods. While being higher in these nutrients, they are also significantly lower in nitrates and pesticide residues. In addition, with the exception of wheat, oats, and wine, organic foods typically provide greater levels of a number of important antioxidant phytochemicals (anthocyanins, flavonoids, and carotenoids). Although in vitro studies of organic fruits and vegetables consistently demonstrate that organic foods have greater antioxidant activity, are more potent suppressors of the mutagenic action of toxic compounds, and inhibit the proliferation of certain cancer cell lines, in vivo studies of antioxidant activity in humans have failed to demonstrate additional benefit. Clear health benefits from consuming organic dairy products have been demonstrated in regard to allergic dermatitis.

Effects of Pig Manure Organic Fertilizer Application on Available Nutrient Content and Soil Aggregate Distribution in Fluvo-aquic Soil

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SHI Wen-xuan

2017-08-01

Full Text Available This paper focuses on environmental risk caused by livestock manure disorderly discharged from integrated livestock and poultry industry. 2-year pot experiment was carried out to study the effects of pig manure organic fertilizer on fluvo-aquic soil organic carbon, available nutrient content and soil aggregate distribution, which designed in 5 levels of organic fertilizer application(0, 6.7, 13.3, 26.7, 40.0 g·kg-1 soil. The results showed that the organic carbon, alkali-hydrolyzable nitrogen, available P and available K contents in soil were enhanced with organic fertilizer application increasing, and the indicators of soil were increased significantly in second year, such as organic carbon content was 2.7%~54.0% higher than that of the first year, alkali-hydrolyzable nitrogen content was higher 6.7%~34.6%, available P content was higher 36.8%~159.5% and available K content was higher 20.3%~35.7%. There was a significant linear relationship between soil organic carbon content and external organic carbon input. Organic fertilizer application could significantly improve lettuce yield, and it had a significant effect. The soil micro-aggregate contents for 0.053~0.25 mm and 0.5 mm soil macro-aggregates were increased with organic fertilizer application increasing. Organic fertilizer application could promote soil macro-aggregates formation, when the pig manure organic fertilizer applied 40.0 g·kg-1 soil, the contents of >0.25 mm soil aggregates reached maximum, and also the mean weight diameter(MWD and geometric average diameter(GWD of soil aggregates were higher than that of other treatments, the soil agglomeration became more stronger and the soil structure became more stable.

Reallocation and nutrient use efficiency in Antioquia central forests

International Nuclear Information System (INIS)

Leon Pelaez, Juan; Gonzalez Hernandez, Maria; Gallardo Lancho, Juan

2009-01-01

We have studied nutrient related variables such as reallocation, nutrient use efficiency (NUE) and fine litter fall for three years in an oak forest Quercus humboldtii Bonpl. and also in some other forest plantations like pine, Pinus patula, and cypress, Cupressus lusitanica, in Antioquia, Colombia. Leaf litter quantities returned to the soil followed a falling sequence: oak (5313.3 kg ha-1 year-1) > pine (4866.5 kg ha-1 year-1) > cypress (2460.3 kg ha-1 year-1). The coniferous species showed the highest NUE for the majority of elements that were examined, except for P, which reached its absolute maximum in the oak forest -where a clear reallocation of this nutrient was also recorded-, probably because of its reduced availability in these volcanic ash-derived soils. Nutrient reallocation allows the conservation of the nutrients by reducing its loss from leaching and litter-fall, thereby closing the nutrient cycle in this native forest. In fact, P gains from net deposition were found there -this includes foliar leaching and atmospheric deposition-, which indicates that the species absorbs the P contained in rainfall from the leaves before it reaches the forest ground. N slow-efficiency use was probably due to its low availability in soil, given its low mineralization rates in these montane forests. K showed the highest reallocation values. Such figures are influenced by its clearly mobile character, according to the highest net deposition levels also verified for this element. With the exception of Mg, there was no clear relationship between the reallocation process and NUE.

Effect of CO2 Enrichment on the Growth and Nutrient Uptake of Tomato Seedlings

Institute of Scientific and Technical Information of China (English)

LI Juan; ZHOU Jian-Min; DUAN Zeng-Qiang; DU Chang-Wen; WANG Huo-Yan

2007-01-01

Exposing tomato seedlings to elevated CO2 concentrations may have potentially profound impacts on the tomato yield and quality. A growth chamber experiment was designed to estimate how different nutrient concentrations influenced the effect of elevated CO2 on the growth and nutrient uptake of tomato seedlings. Tomato (Hezuo 906) was grown in pots placed in controlled growth chambers and was subjected to ambient or elevated CO2 (360 or 720 μL L-1), and four nutrient solutions of different strengths (1/2-, 1/4-, 1/8-, and 1/16-strength Japan Yamazaki nutrient solutions) in a completely randomized design. The results indicated that some agricultural characteristics of the tomato seedlings such as the plant height, stem thickness, total dry and fresh weights of the leaves, stems and roots, the G value (G value = total plant dry weight/seedling age),and the seedling vigor index (seedling vigor index = stem thickness/(plant height × total plant dry weight) increased with the elevated CO2, and the increases were strongly dependent on the nutrient solution concentrations, being greater with higher nutrient solution concentrations. The elevated CO2 did not alter the ratio of root to shoot. The total N, P, K, and C absorbed from all the solutions except P in the 1/8- and 1/16-strength nutrient solutions increased in the elevated CO2 treatment. These results demonstrate that the nutrient demands of the tomato seedlings increased at elevated CO2 concentrations.

Biomass and nutrient allocation strategies in a desert ecosystem in the Hexi Corridor, northwest China.

Science.gov (United States)

Zhang, Ke; Su, YongZhong; Yang, Rong

2017-07-01

The allocation of biomass and nutrients in plants is a crucial factor in understanding the process of plant structures and dynamics to different environmental conditions. In this study, we present a comprehensive scaling analysis of data from a desert ecosystem to determine biomass and nutrient (carbon (C), nitrogen (N), and phosphorus (P)) allocation strategies of desert plants from 40 sites in the Hexi Corridor. We found that the biomass and levels of C, N, and P storage were higher in shoots than in roots. Roots biomass and nutrient storage were concentrated at a soil depth of 0-30 cm. Scaling relationships of biomass, C storage, and P storage between shoots and roots were isometric, but that of N storage was allometric. Results of a redundancy analysis (RDA) showed that soil nutrient densities were the primary factors influencing biomass and nutrient allocation, accounting for 94.5% of the explained proportion. However, mean annual precipitation was the primary factor influencing the roots biomass/shoots biomass (R/S) ratio. Furthermore, Pearson's correlations and regression analyses demonstrated that although the biomass and nutrients that associated with functional traits primarily depended on soil conditions, mean annual precipitation and mean annual temperature had greater effects on roots biomass and nutrient storage.

Wool-waste as organic nutrient source for container-grown plants

Energy Technology Data Exchange (ETDEWEB)

Zheljazkov, Valtcho D. [Mississippi State University, North Mississippi Research and Extension Center, Verona, MS 38879 (United States)], E-mail: vj40@pss.msstate.edu; Stratton, Glenn W [Department of Plant and Animal Sciences and Department of Environmental Sciences, Nova Scotia Agricultural College, Truro, NS, B2N 5E3 (Canada); Pincock, James [Department of Chemistry, Dalhousie University, Halifax, NS, B3H 4J3 (Canada); Butler, Stephanie [Department of Plant and Animal Sciences and Department of Environmental Sciences, Nova Scotia Agricultural College, Truro, NS, B2N 5E3 (Canada); Jeliazkova, Ekaterina A [Mississippi State University, Department of Plant and Soil Sciences, Mississippi State, MS 39762 (United States); Nedkov, Nedko K [Research Institute for Roses and Aromatic Crops, 49 Osvobojdenie Blv., Kazanluk (Bulgaria); Gerard, Patrick D [Department of Applied Economics and Statistics, Clemson University, Clemson, SC 29634 (United States)

2009-07-15

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6-5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2-5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO{sub 3}-N and NH{sub 4}-N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers' surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants.

Wool-waste as organic nutrient source for container-grown plants

International Nuclear Information System (INIS)

Zheljazkov, Valtcho D.; Stratton, Glenn W.; Pincock, James; Butler, Stephanie; Jeliazkova, Ekaterina A.; Nedkov, Nedko K.; Gerard, Patrick D.

2009-01-01

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6-5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2-5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO 3 -N and NH 4 -N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers' surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants.

Micro nutrient status and their distribution in aggregate-size fractions ...

African Journals Online (AJOL)

Micro nutrients are particularly sensitive to changes in land use and their availability in soil is influenced by their distribution and storage in stable aggregate fractions. Micro nutrient, (Fe, Mn and Zn) status and their storage in stable aggregate-size fractions in forested, rubber plantation, oil palm plantation, plantain plantation ...

Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

Science.gov (United States)

Cross, Alison; Perakis, Steven S.

2011-01-01

Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

Fine particle water and pH in the Eastern Mediterranean: Sources, variability and implications for nutrients availability

Science.gov (United States)

Bougiatioti, Aikaterini; Nikolaou, Panayiota; Stavroulas, Iasonas; Kouvarakis, Giorgos; Nenes, Athanasios; Weber, Rodney; Kanakidou, Maria; Mihalopoulos, Nikolaos

2016-04-01

total calculated water. Particle pH is also calculated with the help of ISORROPIA-II, and during the studied period, values varied from 0.5 to 2.8, indicating that the aerosol was highly acidic. pH values were also studied depending on the source/origin of the sampled air masses and biomass burning aerosol was found to exhibit the highest values of PM1 pH and the lowest values in total water mass concentrations. The two natural sources, namely mineral and marine origin, contained the largest amounts of total submicron water and the lowest contribution of organic water, as expected. The low pH values estimated for the studied period in the submicron mode and independently of the air masses' origin could potentially have important implications for nutrient availability, especially for phosphorus solubility, which is the nutrient limiting sea water productivity of the Eastern Mediterranean.

Nutrient and Phytoplankton Analysis of a Mediterranean Coastal Area

Science.gov (United States)

Sebastiá, M. T.; Rodilla, M.

2013-01-01

Identifying and quantifying the key anthropogenic nutrient input sources are essential to adopting management measures that can target input for maximum effect in controlling the phytoplankton biomass. In this study, three systems characterized by distinctive main nutrient sources were sampled along a Mediterranean coast transect. These sources were groundwater discharge in the Ahuir area, the Serpis river discharge in the Venecia area, and a submarine wastewater outfall 1,900 m from the coast. The study area includes factors considered important in determining a coastal area as a sensitive area: it has significant nutrient sources, tourism is a major source of income in the region, and it includes an area of high water residence time (Venecia area) which is affected by the harbor facilities and by wastewater discharges. We found that in the Ahuir and the submarine wastewater outfall areas, the effects of freshwater inputs were reduced because of a greater water exchange with the oligotrophic Mediterranean waters. On the other hand, in the Venecia area, the highest levels of nutrient concentration and phytoplankton biomass were attributed to the greatest water residence time. In this enclosed area, harmful dinoflagellates were detected ( Alexandrium sp. and Dinophysis caudata). If the planned enlargement of the Gandia Harbor proceeds, it may increase the vulnerability of this system and provide the proper conditions of confinement for the dinoflagellate blooms' development. Management measures should first target phosphorus inputs as this is the most potential-limiting nutrient in the Venecia area and comes from a point source that is easier to control. Finally, we recommend that harbor environmental management plans include regular monitoring of water quality in adjacent waters to identify adverse phytoplankton community changes.

Nutrient and phytoplankton analysis of a Mediterranean coastal area.

Science.gov (United States)

Sebastiá, M T; Rodilla, M

2013-01-01

Identifying and quantifying the key anthropogenic nutrient input sources are essential to adopting management measures that can target input for maximum effect in controlling the phytoplankton biomass. In this study, three systems characterized by distinctive main nutrient sources were sampled along a Mediterranean coast transect. These sources were groundwater discharge in the Ahuir area, the Serpis river discharge in the Venecia area, and a submarine wastewater outfall 1,900 m from the coast. The study area includes factors considered important in determining a coastal area as a sensitive area: it has significant nutrient sources, tourism is a major source of income in the region, and it includes an area of high water residence time (Venecia area) which is affected by the harbor facilities and by wastewater discharges. We found that in the Ahuir and the submarine wastewater outfall areas, the effects of freshwater inputs were reduced because of a greater water exchange with the oligotrophic Mediterranean waters. On the other hand, in the Venecia area, the highest levels of nutrient concentration and phytoplankton biomass were attributed to the greatest water residence time. In this enclosed area, harmful dinoflagellates were detected (Alexandrium sp. and Dinophysis caudata). If the planned enlargement of the Gandia Harbor proceeds, it may increase the vulnerability of this system and provide the proper conditions of confinement for the dinoflagellate blooms' development. Management measures should first target phosphorus inputs as this is the most potential-limiting nutrient in the Venecia area and comes from a point source that is easier to control. Finally, we recommend that harbor environmental management plans include regular monitoring of water quality in adjacent waters to identify adverse phytoplankton community changes.

Nutrient Film Technique (NFT Hydroponic Monitoring System

Directory of Open Access Journals (Sweden)

Helmy Helmy

2016-10-01

Full Text Available Plant cultivation using hydroponic is very popular today. Nutrient Film Technique (NFT hydroponic system is commonly used by people. It can be applied indoor or outdoor. Plants in this systemneed nutrient solution to grow well. pH, TDS and temperature of the nutrient solution must be check to ensure plant gets sufficient nutrients. This research aims todevelop monitoring system of NFT hydroponic. Farmer will be able to monitor pH, TDS and temperature online. It will ease farmer to decide which plant is suitable to be cultivated and time to boost growth.Delay of the system will be measured to know system performance. Result shows that pH is directly proportional with TDS. Temperature value has no correlation with pH and TDS. System has highest delay during daylight and afternoon but it will decline in the night and morning. Average of delay in the morning is 11 s, 28.5 s in daylight, 32 s in the afternoon and 17.5 s in the night.

Nutrient fluxes at the landscape level and the R* rule

Science.gov (United States)

Ju, Shu; DeAngelis, Donald L.

2010-01-01

Nutrient cycling in terrestrial ecosystems involves not only the vertical recycling of nutrients at specific locations in space, but also biologically driven horizontal fluxes between different areas of the landscape. This latter process can result in net accumulation of nutrients in some places and net losses in others. We examined the effects of such nutrient-concentrating fluxes on the R* rule, which predicts that the species that can survive in steady state at the lowest level of limiting resource, R*, can exclude all competing species. To study the R* rule in this context, we used a literature model of plant growth and nutrient cycling in which both nutrients and light may limit growth, with plants allocating carbon and nutrients between foliage and roots according to different strategies. We incorporated the assumption that biological processes may concentrate nutrients in some parts of the landscape. We assumed further that these processes draw nutrients from outside the zone of local recycling at a rate proportional to the local biomass density. Analysis showed that at sites where there is a sufficient biomass-dependent accumulation of nutrients, the plant species with the highest biomass production rates (roughly corresponding to the best competitors) do not reduce locally available nutrients to a minimum concentration level (that is, minimum R*), as expected from the R* rule, but instead maximize local nutrient concentration. These new results require broadening of our understanding of the relationships between nutrients and vegetation competition on the landscape level. The R* rule is replaced by a more complex criterion that varies across a landscape and reduces to the R* rule only under certain limiting conditions.

Evaluation of commercially available enzymes, probiotics, or yeast on apparent total-tract nutrient digestion and growth in nursery and finishing pigs fed diets containing corn dried distillers grains with solubles

Science.gov (United States)

The ability of enzymes, direct fed microbials, or yeast to enhance nutrient utilization or growth performance in nursery or finishing pigs fed diets containing increased levels of corn fiber from dried distillers grains with solubles (DDGS) is largely unknown. Ten commercially available feed additiv...

Dynamics of inorganic nutrients in intertidal sediments: porewater, exchangeable and intracellular pools

Directory of Open Access Journals (Sweden)

Emilio eGarcia-Robledo

2016-05-01

Full Text Available The study of inorganic nutrients dynamics in shallow sediments usually focuses on two main pools: the porewater (PW nutrients and the exchangeable (EX ammonium and phosphate. Recently, it has been found that microphytobenthos (MPB and other microorganisms can accumulate large amounts of nutrients intracellularly (IC, highlighting the biogeochemical importance of this nutrient pool. Storing nutrients could support the growth of autotrophs when nutrients are not available, and could also provide alternative electron acceptors for dissimilatory processes such as nitrate reduction. Here, we studied the magnitude and relative importance of these three nutrient pools (PW, IC and EX and their relation to chlorophylls (used as a proxy for MPB abundance and organic matter (OM contents in an intertidal mudflat of Cadiz Bay (Spain. MPB was localized in the first 4 mm of the sediment and showed a clear seasonal pattern; highest chlorophylls content was found during autumn and lowest during spring-summer. The temporal and spatial distribution of nutrients pools and MPB were largely correlated. Ammonium was higher in the IC and EX fractions, representing on average 59 and 37% of the total ammonium pool, respectively. Similarly, phosphate in the IC and EX fractions accounted on average for 40 and 31% of the total phosphate pool, respectively. Nitrate in the PW was low, suggesting low nitrification activity and rapid consumption. Nitrate accumulated in the IC pool during periods of moderate MPB abundance, being up to 66% of the total nitrate pool, whereas it decreased when chlorophyll concentration peaked likely due to a high nitrogen demand. EX-Nitrate accounted for the largest fraction of total sediment nitrate, 66% on average. The distribution of EX-Nitrate was significantly correlated with chlorophyll and OM, which probably indicates a relation of this pool to an increased availability of sites for ionic adsorption. This EX-Nitrate pool could represent an

Experimental evidence for enhanced top-down control of freshwater macrophytes with nutrient enrichment.

Science.gov (United States)

Bakker, Elisabeth S; Nolet, Bart A

2014-11-01

The abundance of primary producers is controlled by bottom-up and top-down forces. Despite the fact that there is consensus that the abundance of freshwater macrophytes is strongly influenced by the availability of resources for plant growth, the importance of top-down control by vertebrate consumers is debated, because field studies yield contrasting results. We hypothesized that these bottom-up and top-down forces may interact, and that consumer impact on macrophyte abundance depends on the nutrient status of the water body. To test this hypothesis, experimental ponds with submerged vegetation containing a mixture of species were subjected to a fertilization treatment and we introduced consumers (mallard ducks, for 8 days) on half of the ponds in a full factorial design. Over the whole 66-day experiment fertilized ponds became dominated by Elodea nuttallii and ponds without extra nutrients by Chara globularis. Nutrient addition significantly increased plant N and P concentrations. There was a strong interactive effect of duck presence and pond nutrient status: macrophyte biomass was reduced (by 50%) after the presence of the ducks on fertilized ponds, but not in the unfertilized ponds. We conclude that nutrient availability interacts with top-down control of submerged vegetation. This may be explained by higher plant palatability at higher nutrient levels, either by a higher plant nutrient concentration or by a shift towards dominance of more palatable plant species, resulting in higher consumer pressure. Including nutrient availability may offer a framework to explain part of the contrasting field observations of consumer control of macrophyte abundance.

Nutrient digestibility and mass balance in laying hens fed a commercial or acidifying diet.

Science.gov (United States)

Wu-Haan, W; Powers, W J; Angel, C R; Hale, C E; Applegate, T J

2007-04-01

The objectives of the current study were to evaluate the effect of an acidifying diet (gypsum) combined with zeolite and slightly reduced crude protein (R) vs. a control diet (C) on nutrient retention in laying hens and compare 3 approaches to estimating nutrient excretion from hens: 1) mass balance calculation (feed nutrients - egg nutrient), 2) use of an indigestible marker with analyzed feed and excreta nutrient content, and 3) an environmental chamber that allowed for capturing all excreted and volatilized nutrients. Hens (n = 640) were allocated randomly to 8 environmental chambers for 3-wk periods. Excreta samples were collected at the end of each trial to estimate apparent retention of N, S, P, and Ca. No diet effects on apparent retention of N were observed (53.44%, P > 0.05). Apparent retention of S, P, and Ca decreased in hens fed R diet (18.7, - 11.4, and 22.6%, respectively) compared with hens fed the C diet (40.7, 0.3, and 28.6%, respectively; P < 0.05). Total N excretion from hens fed the C and R diet was not different (1.16 g/hen/d); however, mass of chamber N remaining in excreta following the 3-wk period was less from hens fed the C diet (1.27 kg) than from hens fed the R diet (1.43 kg). Gaseous emissions of NH(3) over the 3-wk period from hens fed the C diet (0.74 kg per chamber) were greater than emissions from hens fed the R diet (0.45 kg). The 3-wk S excretion mass (estimated using the calculation, indigestible marker, and environmental chamber methods, respectively) was greater from hens fed the R diet (1.85, 1.54, and 1.27 kg, respectively) compared with hens fed the C diet (0.24, 0.20, and 0.14 kg, respectively). The 3-wk P excretion was similar between diets (0.68 kg). Results demonstrate that feeding the acidified diet resulted in decreased N emissions, but because of the acidulant fed, greatly increased S excretion and emissions.

Transport of biologically important nutrients by wind in an eroding cold desert

Science.gov (United States)

Sankey, Joel B.; Germino, Matthew J.; Benner, Shawn G.; Glenn, Nancy F.; Hoover, Amber N.

2012-01-01

Wind erosion following fire is an important landscape process that can result in the redistribution of ecologically important soil resources. In this study we evaluated the potential for a fire patch in a desert shrubland to serve as a source of biologically important nutrients to the adjacent, downwind, unburned ecosystem. We analyzed nutrient concentrations (P, K, Ca, Mg, Cu, Fe, Mn, Al) in wind-transported sediments, and soils from burned and adjacent unburned surfaces, collected during the first to second growing seasons after a wildfire that burned in 2007 in Idaho, USA in sagebrush steppe; a type of cold desert shrubland. We also evaluated the timing of potential wind erosion events and weather conditions that might have contributed to nutrient availability in downwind shrubland. Findings indicated that post-fire wind erosion resulted in an important, but transient, addition of nutrients on the downwind shrubland. Aeolian sediments from the burned area were enriched relative to both the up- and down-wind soil and indicated the potential for a fertilization effect through the deposition of the nutrient-enriched sediment during the first, but not second, summer after wildfire. Weather conditions that could have produced nutrient transport events might have provided increased soil moisture necessary to make nutrients accessible for plants in the desert environment. Wind transport of nutrients following fire is likely important in the sagebrush steppe as it could contribute to pulses of resource availability that might, for example, affect plant species differently depending on their phenology, and nutrient- and water-use requirements.

Lateral diffusion of nutrients by mammalian herbivores in terrestrial ecosystems.

Directory of Open Access Journals (Sweden)

Adam Wolf

Full Text Available Animals translocate nutrients by consuming nutrients at one point and excreting them or dying at another location. Such lateral fluxes may be an important mechanism of nutrient supply in many ecosystems, but lack quantification and a systematic theoretical framework for their evaluation. This paper presents a mathematical framework for quantifying such fluxes in the context of mammalian herbivores. We develop an expression for lateral diffusion of a nutrient, where the diffusivity is a biologically determined parameter depending on the characteristics of mammals occupying the domain, including size-dependent phenomena such as day range, metabolic demand, food passage time, and population size. Three findings stand out: (a Scaling law-derived estimates of diffusion parameters are comparable to estimates calculated from estimates of each coefficient gathered from primary literature. (b The diffusion term due to transport of nutrients in dung is orders of magnitude large than the coefficient representing nutrients in bodymass. (c The scaling coefficients show that large herbivores make a disproportionate contribution to lateral nutrient transfer. We apply the diffusion equation to a case study of Kruger National Park to estimate the conditions under which mammal-driven nutrient transport is comparable in magnitude to other (abiotic nutrient fluxes (inputs and losses. Finally, a global analysis of mammalian herbivore transport is presented, using a comprehensive database of contemporary animal distributions. We show that continents vary greatly in terms of the importance of animal-driven nutrient fluxes, and also that perturbations to nutrient cycles are potentially quite large if threatened large herbivores are driven to extinction.

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia.

Science.gov (United States)

van der Wulp, Simon A; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J

2016-09-30

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m(3)s(-1) entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

A mathematical function for the description of nutrient-response curve.

Directory of Open Access Journals (Sweden)

Hamed Ahmadi

Full Text Available Several mathematical equations have been proposed to modeling nutrient-response curve for animal and human justified on the goodness of fit and/or on the biological mechanism. In this paper, a functional form of a generalized quantitative model based on Rayleigh distribution principle for description of nutrient-response phenomena is derived. The three parameters governing the curve a has biological interpretation, b may be used to calculate reliable estimates of nutrient response relationships, and c provide the basis for deriving relationships between nutrient and physiological responses. The new function was successfully applied to fit the nutritional data obtained from 6 experiments including a wide range of nutrients and responses. An evaluation and comparison were also done based simulated data sets to check the suitability of new model and four-parameter logistic model for describing nutrient responses. This study indicates the usefulness and wide applicability of the new introduced, simple and flexible model when applied as a quantitative approach to characterizing nutrient-response curve. This new mathematical way to describe nutritional-response data, with some useful biological interpretations, has potential to be used as an alternative approach in modeling nutritional responses curve to estimate nutrient efficiency and requirements.

Continental-Scale Effects of Nutrient Pollution on Stream Ecosystem Functioning

OpenAIRE

Woodward , Guy; Gessner , Mark O.; Giller , Paul S.; Gulis , Vladislav; Hladyz , Sally; Lecerf , Antoine; Malmqvist , Björn; McKie , Brendan G.; Tiegs , Scott D.; Cariss , Helen; Dobson , Mike; Elosegi , Arturo; Ferreira , Veronica; Graça , Manuel A. S.; Fleituch , Tadeusz

2012-01-01

International audience; Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 100...

Socioeconomic status, energy cost, and nutrient content of supermarket food purchases.

Science.gov (United States)

Appelhans, Bradley M; Milliron, Brandy-Joe; Woolf, Kathleen; Johnson, Tricia J; Pagoto, Sherry L; Schneider, Kristin L; Whited, Matthew C; Ventrelle, Jennifer C

2012-04-01

The relative affordability of energy-dense versus nutrient-rich foods may promote socioeconomic disparities in dietary quality and obesity. Although supermarkets are the largest food source in the American diet, the associations between SES and the cost and nutrient content of freely chosen food purchases have not been described. To investigate relationships of SES with the energy cost ($/1000 kcal) and nutrient content of freely chosen supermarket purchases. Supermarket shoppers (n=69) were recruited at a Phoenix AZ supermarket in 2009. The energy cost and nutrient content of participants' purchases were calculated from photographs of food packaging and nutrition labels using dietary analysis software. Data were analyzed in 2010-2011. Two SES indicators, education and household income as a percentage of the federal poverty guideline (FPG), were associated with the energy cost of purchased foods. Adjusting for covariates, the amount spent on 1000 kcal of food was $0.26 greater for every multiple of the FPG, and those with a baccalaureate or postbaccalaureate degree spent an additional $1.05 for every 1000 kcal of food compared to those with no college education. Lower energy cost was associated with higher total fat and less protein, dietary fiber, and vegetables per 1000 kcal purchased. Low-SES supermarket shoppers purchase calories in inexpensive forms that are higher in fat and less nutrient-rich. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Sources of Nutrients to Nearshore Areas of a Eutrophic Estuary: Implications for Nutrient-Enhanced Acidification in Puget Sound

Science.gov (United States)

Pacella, S. R.

2016-02-01

Ocean acidification has recently been highlighted as a major stressor for coastal organisms. Further work is needed to assess the role of anthropogenic nutrient additions in eutrophied systems on local biological processes, and how this interacts with CO2 emission-driven acidification. This study sought to distinguish changes in pH caused by natural versus anthropogenically affected processes. We quantified the variability in water column pH attributable to primary production and respiration fueled by anthropogenically derived nitrogen in a shallow nearshore area. Two study sites were located in shallow subtidal areas of the Snohomish River estuary, a eutrophic system located in central Puget Sound, Washington. These sites were chosen due to the presence of heavy agricultural activity, urbanized areas with associated waste water treatment, as well as influence from deep, high CO2 marine waters transported through the Strait of Juan de Fuca and upwelled into the area during spring and summer. Data was collected from July-December 2015 utilizing continuous moorings and discrete water column sampling. Analysis of stable isotopes, δ15N, δ18O-NO3, δ15N-NH4, was used to estimate the relative contributions of anthropogenic versus upwelled marine nitrogen sources. Continuous monitoring of pH, dissolved oxygen, temperature, and salinity was conducted at both study sites to link changes in nutrient source and availability with changes in pH. We predicted that isotope data would indicate greater contributions of nitrogen from agriculture and wastewater rather than upwelling in the shallow, nearshore study sites. This study seeks to distinguish the relative magnitude of pH change stimulated by anthropogenic versus natural sources of nitrogen to inform public policy decisions in critically important nearshore ecosystems.

Determination of zinc nutrient in the soil using isotope technique

International Nuclear Information System (INIS)

Suwadji, E.

1975-01-01

In this experiment the availability of soil Zn nutrient in various soil conditions (dry and submerged), and the efficiency of the application of Zn fertilizer in rice nutrition were measured in glasshouse using isotope dilution technique. The amount of soil Zn nutrient available to plants can be expressed in 'E' and 'L' values. Submerged conditions generally showed an increase in the 'E' and 'L' value compared to dry conditions. Mixed treatment with ZnSO 4 fertilizer is more efficient for Zn absorption than surface treatment. (author)

[An optical-fiber-sensor-based spectrophotometer for soil non-metallic nutrient determination].

Science.gov (United States)

He, Dong-xian; Hu, Juan-xiu; Lu, Shao-kun; He, Hou-yong

2012-01-01

In order to achieve rapid, convenient and efficient soil nutrient determination in soil testing and fertilizer recommendation, a portable optical-fiber-sensor-based spectrophotometer including immersed fiber sensor, flat field holographic concave grating, and diode array detector was developed for soil non-metallic nutrient determination. According to national standard of ultraviolet and visible spectrophotometer with JJG 178-2007, the wavelength accuracy and repeatability, baseline stability, transmittance accuracy and repeatability measured by the prototype instrument were satisfied with the national standard of III level; minimum spectral bandwidth, noise and excursion, and stray light were satisfied with the national standard of IV level. Significant linear relationships with slope of closing to 1 were found between the soil available nutrient contents including soil nitrate nitrogen, ammonia nitrogen, available phosphorus, available sulfur, available boron, and organic matter measured by the prototype instrument compared with that measured by two commercial single-beam-based and dual-beam-based spectrophotometers. No significant differences were revealed from the above comparison data. Therefore, the optical-fiber-sensor-based spectrophotometer can be used for rapid soil non-metallic nutrient determination with a high accuracy.

Produção de serapilheira e ciclagem de nutrientes na cultura do cajueiro anão precoce Litter production and nutrient cycles in the young dwarf cashew culture

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Ismail Soares

2008-02-01

decomposição das folhas.This study aimed to (a to evaluate the biomass production from the crown of the young dwarf cashew, clone CCP 76, at 2, 3, 8 and 9 years of culture implantation, (b to determine the rate of leaf decomposition and (c to quantify nutrient contribution potentially available in the biomass to be recycled into the soil. The research was conducted at the Experimental Field of Curu, in Paraipaba - CE, from December, 2003 to January, 2005. The treatments consisted of orchards with trees of 2, 3, 8 and 9 years of plantation, distributed in a completely randomized design with eight replications. Litter was collected using 1 m² collectors with 1 mm² mesh place 40 cm above the soil surface. After sampling, the material was sorted out into portions of leaves, branches, inflorescence, peduncle and nut, oven dried and weighed. In the leaf portion, the compositions of N, P, K, Ca, Mg, S, Na, Cu, Fe, Mn and Zn were determined. Leaves ready to fall were collected from each plant to determine their decomposition rate and 12 g of this material was stove dried, and placed in 20 cm x 20 cm nylon bags and 2 mm mesh which were distributed on the soil surface and collected after 112, 233 and 369 days. In each collection, the material was oven dried and the remaining nutrient biomass (N, P, K, Ca, Mg, S, Na, Cu, Fe, Mn and Zn was determined. The 8- and 9- year- old plants deposited greater quantities of litter during the experimental period and showed greater potential for nutrient recycling. During the experimental period it was generally observed that the decomposition process was fast in the first four months, remaining slow until the end of the observation period. Most of the nutrients in the cashew tree were released in the first four months of leaf composition.

Vertical flow constructed wetlands: kinetics of nutrient and organic matter removal.

Science.gov (United States)

Pérez, M M; Hernández, J M; Bossens, J; Jiménez, T; Rosa, E; Tack, F

2014-01-01

The kinetics of organic matter and nutrient removal in a pilot vertical subsurface wetland with red ferralitic soil as substrate were evaluated. The wetland (20 m(2)) was planted with Cyperus alternifolius. The domestic wastewater that was treated in the wetland had undergone a primary treatment consisting of a septic moat and a buffer tank. From the sixth week of operation, the performance of the wetland stabilized, and a significant reduction in pollutant concentration of the effluent wastewater was obtained. Also a significant increase of dissolved oxygen (5 mg/l) was obtained. The organic matter removal efficiency was greater than 85% and the nutrient removal efficiency was greater than 75% in the vertical subsurface wetland. Nitrogen and biochemical oxygen demand (BOD) removal could be described by a first-order model. The kinetic constants were 3.64 and 3.27 d(-1) for BOD and for total nitrogen, respectively. Data on the removal of phosphorus were adapted to a second-order model. The kinetic constant was 0.96 (mg/l)(-1) d(-1). The results demonstrated the potential of vertical flow constructed wetlands to clean treated domestic wastewater before discharge into the environment.

The sum of its parts--effects of gastric distention, nutrient content and sensory stimulation on brain activation.

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Maartje S Spetter

Full Text Available During food consumption the brain integrates multiple interrelated neural and hormonal signals involved in the regulation of food intake. Factors influencing the decision to stop eating include the foods' sensory properties, macronutrient content, and volume, which in turn affect gastric distention and appetite hormone responses. So far, the contributions of gastric distention and oral stimulation by food on brain activation have not been studied. The primary objective of this study was to assess the effect of gastric distention with an intra-gastric load and the additional effect of oral stimulation on brain activity after food administration. Our secondary objective was to study the correlations between hormone responses and appetite-related ratings and brain activation. Fourteen men completed three functional magnetic resonance imaging sessions during which they either received a naso-gastric infusion of water (stomach distention, naso-gastric infusion of chocolate milk (stomach distention + nutrients, or ingested chocolate-milk (stomach distention + nutrients + oral exposure. Appetite ratings and blood parameters were measured at several time points. During gastric infusion, brain activation was observed in the midbrain, amygdala, hypothalamus, and hippocampus for both chocolate milk and water, i.e., irrespective of nutrient content. The thalamus, amygdala, putamen and precuneus were activated more after ingestion than after gastric infusion of chocolate milk, whereas infusion evoked greater activation in the hippocampus and anterior cingulate. Moreover, areas involved in gustation and reward were activated more after oral stimulation. Only insulin responses following naso-gastric infusion of chocolate milk correlated with brain activation, namely in the putamen and insula. In conclusion, we show that normal (oral food ingestion evokes greater activation than gastric infusion in stomach distention and food intake-related brain areas. This

Growth Responses of Three Dominant Wetland Plant Species to Various Flooding and Nutrient Levels

Science.gov (United States)

Barrett, S.; Shaffer, G. P.

2017-12-01

Coastal Louisiana is experiencing a greater rate of wetland loss than any other wetland system in the United States. This is primarily due to anthropogenic stressors such as flood control levees, backfilling and development of wetlands, and other hydrologic modifications. Methods employed to mitigate wetland loss include the construction of river diversions and assimilation wetlands, which can provide consistent sources of freshwater influx and nutrients to impounded swamps and marshes. It is well known that prolonged flooding causes strain on wetland plant communities and facilitates or exacerbates wetland degradation. However, because river diversions and assimilation wetlands bring high nutrient loads along with freshwater, there is debate over whether prolonged flooding or high influx of nutrients is the primary cause of stress in river diversion and assimilation wetland discharge areas. This mesocosm experiment addresses this question by isolating the effects of flooding and nutrients on the biomass of baldcypress (Taxodium distichum), maidencane (Panicum hemitomon), and cordgrass (Spartina patens) over the course of a growing season. The results of this study provide clarity as to whether flooding stress, high nutrient loads, or both cause a reduction in wetland plant productivity. By evaluating the growth responses of T. distichum, P. hemitomon, and S. patens at varying nutrient regimes, we gain insight on how these more dominant species will react to high nutrient discharges from large river diversions, such as those proposed in Louisiana's 2017 Master Plan.

Role of Nutrient-Sensing Signals in the Pathogenesis of Diabetic Nephropathy

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Shinji Kume

2014-01-01

Full Text Available Diabetic nephropathy is the leading cause of end-stage renal disease worldwide. The multipronged drug approach still fails to fully prevent the onset and progression of diabetic nephropathy. Therefore, a new therapeutic target to improve the prognosis of diabetic nephropathy is urgently required. Nutrient-sensing signals and their related intracellular machinery have evolved to combat prolonged periods of starvation in mammals; and these systems are conserved in the kidney. Recent studies have suggested that the activity of three nutrient-sensing signals, mTORC1, AMPK, and Sirt1, is altered in the diabetic kidney. Furthermore, autophagy activity, which is regulated by the above-mentioned nutrient-sensing signals, is also altered in both podocytes and proximal tubular cells under diabetic conditions. Under diabetic conditions, an altered nutritional state owing to nutrient excess may disturb cellular homeostasis regulated by nutrient-responsible systems, leading to exacerbation of organelle dysfunction and diabetic nephropathy. In this review, we discuss new findings showing relationships between nutrient-sensing signals, autophagy, and diabetic nephropathy and suggest the therapeutic potential of nutrient-sensing signals in diabetic nephropathy.

Effects of shelter and enrichment on the ecology and nutrient cycling of microbial communities of subtidal carbonate sediments.

Science.gov (United States)

Forehead, Hugh I; Kendrick, Gary A; Thompson, Peter A

2012-04-01

The interactions between physical disturbances and biogeochemical cycling are fundamental to ecology. The benthic microbial community controls the major pathway of nutrient recycling in most shallow-water ecosystems. This community is strongly influenced by physical forcing and nutrient inputs. Our study tests the hypotheses that benthic microbial communities respond to shelter and enrichment with (1) increased biomass, (2) change in community composition and (3) increased uptake of inorganic nutrients from the water column. Replicate in situ plots were sheltered from physical disturbance and enriched with inorganic nutrients or left without additional nutrients. At t(0) and after 10 days, sediment-water fluxes of nutrients, O(2) and N(2) , were measured, the community was characterized with biomarkers. Autochthonous benthic microalgal (BMA) biomass increased 30% with shelter and a natural fivefold increase in nutrient concentration; biomass did not increase with greater enrichment. Diatoms remained the dominant taxon of BMA, suggesting that the sediments were not N or Si limited. Bacteria and other heterotrophic organisms increased with enrichment and shelter. Daily exchanges of inorganic nutrients between sediments and the water column did not change in response to shelter or nutrient enrichment. In these sediments, physical disturbance, perhaps in conjunction with nutrient enrichment, was the primary determinant of microbial biomass. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Early root overproduction not triggered by nutrients decisive for competitive success belowground.

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Francisco M Padilla

Full Text Available Theory predicts that plant species win competition for a shared resource by more quickly preempting the resource in hotspots and by depleting resource levels to lower concentrations than its competitors. Competition in natural grasslands largely occurs belowground, but information regarding root interactions is limited, as molecular methods quantifying species abundance belowground have only recently become available.In monoculture, the grass Festuca rubra had higher root densities and a faster rate of soil nitrate depletion than Plantago lanceolata, projecting the first as a better competitor for nutrients. However, Festuca lost in competition with Plantago. Plantago not only replaced the lower root mass of its competitor, but strongly overproduced roots: with only half of the plants in mixture than in monoculture, Plantago root densities in mixture were similar or higher than those in its monocultures. These responses occurred equally in a nutrient-rich and nutrient-poor soil layer, and commenced immediately at the start of the experiment when root densities were still low and soil nutrient concentrations high.Our results suggest that species may achieve competitive superiority for nutrients by root growth stimulation prior to nutrient depletion, induced by the presence of a competitor species, rather than by a better ability to compete for nutrients per se. The root overproduction by which interspecific neighbors are suppressed independent of nutrient acquisition is consistent with predictions from game theory. Our results emphasize that root competition may be driven by other mechanisms than is currently assumed. The long-term consequences of these mechanisms for community dynamics are discussed.

Nutrient control of eukaryote cell growth: a systems biology study in yeast

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Lilley Kathryn S

2010-05-01

Full Text Available Abstract Background To elucidate the biological processes affected by changes in growth rate and nutrient availability, we have performed a comprehensive analysis of the transcriptome, proteome and metabolome responses of chemostat cultures of the yeast, Saccharomyces cerevisiae, growing at a range of growth rates and in four different nutrient-limiting conditions. Results We find significant changes in expression for many genes in each of the four nutrient-limited conditions tested. We also observe several processes that respond differently to changes in growth rate and are specific to each nutrient-limiting condition. These include carbohydrate storage, mitochondrial function, ribosome synthesis, and phosphate transport. Integrating transcriptome data with proteome measurements allows us to identify previously unrecognized examples of post-transcriptional regulation in response to both nutrient and growth-rate signals. Conclusions Our results emphasize the unique properties of carbon metabolism and the carbon substrate, the limitation of which induces significant changes in gene regulation at the transcriptional and post-transcriptional level, as well as altering how many genes respond to growth rate. By comparison, the responses to growth limitation by other nutrients involve a smaller set of genes that participate in specific pathways. See associated commentary http://www.biomedcentral.com/1741-7007/8/62

Seasonality of nutrients in leaves and fruits of apple trees

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Nachtigall Gilmar Ribeiro

2006-01-01

Full Text Available The nutrient accumulation curves of apple trees are good indicators of plant nutrient demand for each developmental stage. They are also a useful tool to evaluate orchard nutritional status and to estimate the amount of soil nutrient removal. This research aimed at evaluating the seasonality of nutrients in commercial apple orchards during the agricultural years of 1999, 2000, and 2001. Therefore, apple tree leaves and fruits of three cultivars 'Gala', 'Golden Delicious' and 'Fuji' were weekly collected and evaluated for fresh and dry matter, fruit diameter and macronutrient (N, P, K, Ca and Mg and micronutrient (B, Cu, Fe, Mn, and Zn concentrations. Leaf and fruit sampling started one or two weeks after full bloom, depending on the cultivar, and ended at fruit harvest or four weeks later (in the case of leaf sampling. In general, leaf concentrations of N, P, K, Cu, and B decreased; Ca increased; and Mg, Fe, Mn, and Zn did vary significantly along the plant vegetative cycle. In fruits, the initial nutrient concentrations decreased quickly, undergoing slow and continuous decreases and then remaining almost constant until the end of fruit maturation, indicating nutrient dilution, once the total nutrient accumulation increased gradually with fruit growth. Potassium was the nutrient present in highest quantities in apple tree fruits and thus, the most removed from the soil.

Biomass decomposition and nutrient release from black oat and hairy vetch residues deposited in a vineyard

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Paulo Ademar Avelar Ferreira

2014-10-01

Full Text Available A significant quantity of nutrients in vineyards may return to the soil each year through decomposition of residues from cover plants. This study aimed to evaluate biomass decomposition and nutrient release from residues of black oats and hairy vetch deposited in the vines rows, with and without plastic shelter, and in the between-row areas throughout the vegetative and productive cycle of the plants. The study was conducted in a commercial vineyard in Bento Gonçalves, RS, Brazil, from October 2008 to February 2009. Black oat (Avena strigosa and hairy vetch (Vicia villosa residues were collected, subjected to chemical (C, N, P, K, Ca, and Mg and biochemical (cellulose - Cel, hemicellulose - Hem, and lignin - Lig content analyses, and placed in litter bags, which were deposited in vines rows without plastic shelter (VPRWS, in vines rows with plastic shelter (VPRS, and in the between-row areas (BR. We collected the residues at 0, 33, 58, 76, and 110 days after deposition of the litter bags, prepared the material, and subjected it to analysis of total N, P, K, Ca, and Mg content. The VPRS contained the largest quantities and percentages of dry matter and residual nutrients (except for Ca in black oat residues from October to February, which coincides with the period from flowering up to grape harvest. This practice led to greater protection of the soil surface, avoiding surface runoff of the solution derived from between the rows, but it retarded nutrient cycling. The rate of biomass decomposition and nutrient release from hairy vetch residues from October to February was not affected by the position of deposition of the residues in the vineyard, which may especially be attributed to the lower values of the C/N and Lig/N ratios. Regardless of the type of residue, black oat or hairy vetch, the greatest decomposition and nutrient release mainly occurred up to 33 days after deposition of the residues on the soil surface, which coincided with the

Microbial planktonic communities in the Red Sea: high levels of spatial and temporal variability shaped by nutrient availability and turbulence

KAUST Repository

Pearman, John K.; Ellis, Joanne; Irigoien, Xabier; Yellepeddi, Sarma B.; Jones, Burton; Carvalho, Susana

2017-01-01

The semi-enclosed nature of the Red Sea (20.2°N-38.5°N) makes it a natural laboratory to study the influence of environmental gradients on microbial communities. This study investigates the composition and structure of microbial prokaryotes and eukaryotes using molecular methods, targeting ribosomal RNA genes across different regions and seasons. The interaction between spatial and temporal scales results in different scenarios of turbulence and nutrient conditions allowing for testing of ecological theory that categorizes the response of the plankton community to these variations. The prokaryotic reads are mainly comprised of Cyanobacteria and Proteobacteria (Alpha and Gamma), with eukaryotic reads dominated by Dinophyceae and Syndiniophyceae. Periodic increases in the proportion of Mamiellophyceae and Bacillariophyceae reads were associated with alterations in the physical oceanography leading to nutrient increases either through the influx of Gulf of Aden Intermediate Water (south in the fall) or through water column mixing processes (north in the spring). We observed that in general dissimilarity amongst microbial communities increased when nutrient concentrations were higher, whereas richness (observed OTUs) was higher in scenarios of higher turbulence. Maximum abundance models showed the differential responses of dominant taxa to temperature giving an indication how taxa will respond as waters become warmer and more oligotrophic.

Microbial planktonic communities in the Red Sea: high levels of spatial and temporal variability shaped by nutrient availability and turbulence

KAUST Repository

Pearman, John K.

2017-07-20

The semi-enclosed nature of the Red Sea (20.2°N-38.5°N) makes it a natural laboratory to study the influence of environmental gradients on microbial communities. This study investigates the composition and structure of microbial prokaryotes and eukaryotes using molecular methods, targeting ribosomal RNA genes across different regions and seasons. The interaction between spatial and temporal scales results in different scenarios of turbulence and nutrient conditions allowing for testing of ecological theory that categorizes the response of the plankton community to these variations. The prokaryotic reads are mainly comprised of Cyanobacteria and Proteobacteria (Alpha and Gamma), with eukaryotic reads dominated by Dinophyceae and Syndiniophyceae. Periodic increases in the proportion of Mamiellophyceae and Bacillariophyceae reads were associated with alterations in the physical oceanography leading to nutrient increases either through the influx of Gulf of Aden Intermediate Water (south in the fall) or through water column mixing processes (north in the spring). We observed that in general dissimilarity amongst microbial communities increased when nutrient concentrations were higher, whereas richness (observed OTUs) was higher in scenarios of higher turbulence. Maximum abundance models showed the differential responses of dominant taxa to temperature giving an indication how taxa will respond as waters become warmer and more oligotrophic.

Combined Influence of Landscape Composition and Nutrient Inputs on Lake Trophic Structure

Science.gov (United States)

The concentration of chlorophyll a is a measure of the biological productivity of a lake and is largely (but not exclusively) determined by available nutrients. As nutrient inputs increase, productivity increases and lakes transition from low trophic state (e.g. oligotrophic) to...

Parent's responses to nutrient claims and sports celebrity endorsements on energy-dense and nutrient-poor foods: an experimental study.

Science.gov (United States)

Dixon, Helen; Scully, Maree; Wakefield, Melanie; Kelly, Bridget; Chapman, Kathy; Donovan, Robert

2011-06-01

To assess parents' responses to common, potentially misleading strategies for marketing energy-dense and nutrient-poor (EDNP) child-oriented foods. Between-subjects online experiment to test whether nutrient claims and sports celebrity endorsements on the front of packs of EDNP products lead parents to prefer and rate these foods more favourably. Australia. A total of 1551 parents of children aged 5-12 years, who were the main household grocery buyers. Inclusion of nutrient claims or sports celebrity endorsements on EDNP products led parents to perceive these products to be more nutritious than if they did not include such promotions. When asked to choose between a pair of different products (EDNP v. healthier), 56 % of parents did not read a nutrition information panel (NIP) before making their choice and this did not differ by promotion condition. These parents were more likely to choose an EDNP product if it included a nutrient claim (OR = 1.83, 95 % CI 1.31, 2.56; P foods are available to children at home, it is critical that initiatives aimed at reducing the persuasive impact of food marketing include this target group.

Deciphering relationships between in-stream travel times, nutrient concentrations, and uptake through analysis of hysteretic and non-hysteretic kinetic behavior

Science.gov (United States)

Covino, T. P.; Bowden, W. B.; Gooseff, M. N.; Wollheim, W. M.; McGlynn, B. L.; Whittinghill, K. A.; Wlostowski, A. N.; Herstand, M. R.

2012-12-01

Understanding the relationship between solute travel time, concentration, and nutrient uptake remains a central question in watershed hydrology and biogeochemistry. Theoretical understanding predicts that nutrient uptake should increase as in-stream solute travel time lengthens and/or as concentration increases; however, results from field-based studies have been contradictory. We used a newly developed approach, Tracer Additions for Spiraling Curve Characterization (TASCC), to investigate relationships between solute travel time, nutrient concentration, and nutrient uptake across a range of stream types. This approach allows us to quantify in-stream nutrient uptake across a range of travel times and nutrient concentrations using single instantaneous injections (slugs) of conservative and non-conservative tracers. In some systems we observed counter-clockwise hysteresis loops in the relationship between nutrient uptake and concentration. Greater nutrient uptake on the falling limb of tracer breakthrough curves indicates stronger uptake for a given concentration at longer travel times. However, in other systems we did not observe hysteresis in these relationships. Lack of hysteresis indicates that nutrient uptake kinetics were not influenced by travel time travel time. Here we investigate the potential roles of travel time and in-stream flowpaths that could be responsible for hysteretic behavior.

Effects of soil nutrient heterogeneity on intraspecific competition in the invasive, clonal plant Alternanthera philoxeroides.

Science.gov (United States)

Zhou, Jian; Dong, Bi-Cheng; Alpert, Peter; Li, Hong-Li; Zhang, Ming-Xiang; Lei, Guang-Chun; Yu, Fei-Hai

2012-03-01

Fine-scale, spatial heterogeneity in soil nutrient availability can increase the growth of individual plants, the productivity of plant communities and interspecific competition. If this is due to the ability of plants to concentrate their roots where nutrient levels are high, then nutrient heterogeneity should have little effect on intraspecific competition, especially when there are no genotypic differences between individuals in root plasticity. We tested this hypothesis in a widespread, clonal species in which individual plants are known to respond to nutrient heterogeneity. Plants derived from a single clone of Alternanthera philoxeroides were grown in the greenhouse at low or high density (four or 16 plants per 27·5 × 27·5-cm container) with homogeneous or heterogeneous availability of soil nutrients, keeping total nutrient availability per container constant. After 9 weeks, measurements of size, dry mass and morphology were taken. Plants grew more in the heterogeneous than in the homogeneous treatment, showing that heterogeneity promoted performance; they grew less in the high- than in the low-density treatment, showing that plants competed. There was no interactive effect of nutrient heterogeneity and plant density, supporting the hypothesis that heterogeneity does not affect intraspecific competition in the absence of genotypic differences in plasticity. Treatments did not affect morphological characteristics such as specific leaf area or root/shoot ratio. Results indicate that fine-scale, spatial heterogeneity in the availability of soil nutrients does not increase competition when plants are genetically identical, consistent with the suggestion that effects of heterogeneity on competition depend upon differences in plasticity between individuals. Heterogeneity is only likely to increase the spread of monoclonal, invasive populations such as that of A. philoxeroides in China.

AMF Inoculation Enhances Growth and Improves the Nutrient Uptake Rates of Transplanted, Salt-Stressed Tomato Seedlings

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Astrit Balliu

2015-12-01

Full Text Available The study aimed to investigate the effects of commercially available AMF inoculate (Glomus sp. mixture on the growth and the nutrient acquisition in tomato (Solanumlycopersicum L. plants directly after transplanting and under different levels of salinity. Inoculated (AMF+ and non-inoculated (AMF− tomato plants were subjected to three levels of NaCl salinity (0, 50, and 100 mM·NaCl. Seven days after transplanting, plants were analyzed for dry matter and RGR of whole plants and root systems. Leaf tissue was analyzed for mineral concentration before and after transplanting; leaf nutrient content and relative uptake rates (RUR were calculated. AMF inoculation did not affect plant dry matter or RGR under fresh water-irrigation. The growth rate of AMF−plants did significantly decline under both moderate (77% and severe (61% salt stress compared to the fresh water-irrigated controls, while the decline was much less (88% and 75%,respectivelyand statistically non-significant in salt-stressed AMF+ plants. Interestingly, root system dry matter of AMF+ plants (0.098 g plant–1 remained significantly greater under severe soil salinity compared to non-inoculated seedlings (0.082 g plant–1. The relative uptake rates of N, P, Mg, Ca, Mn, and Fe were enhanced in inoculated tomato seedlings and remained higher under (moderate salt stress compared to AMF− plants This study suggests that inoculation with commercial AMF during nursery establishment contributes to alleviation of salt stress by maintaining a favorable nutrient profile. Therefore, nursery inoculation seems to be a viable solution to attenuate the effects of increasing soil salinity levels, especially in greenhouses with low natural abundance of AMF spores.

Effects of site management operations on the nutrient capital of a ...

African Journals Online (AJOL)

The Karkloof Project is a case study of the effects of intensive site management operations during the interrotational period, on (a) the nutrient capital of the system, and (b) the availability of growth resources (nutrients and water) in a commercial Eucalyptus grandis stand in South Africa. This paper specifically focuses on the ...

[Changes of soil nutrient contents after prescribed burning of forestland in Heshan City, Guangdong Province].

Science.gov (United States)

Sun, Yu-xin; Wu, Jian-ping; Zhou, Li-xia; Lin, Yong-biao; Fu, Sheng-lei

2009-03-01

A comparative study was conducted to analyze the changes of soil nutrient contents in Eucalyptus forestland and in shrubland after three years of prescribed burning. In Eucalyptus forestland, soil organic carbon, total nitrogen, available potassium contents and soil pH decreased significantly; soil available phosphorus and exchangeable magnesium contents, net nitrogen mineralization rate and ammonification rate also decreased but showed no significant difference. In shrubland, soil exchangeable calcium content increased significantly, but the contents of other nutrients had no significant change. The main reason of the lower soil net nitrogen mineralization rate in Eucalyptus forest could be the decrease of available substrates and the uptake of larger amount of soil nutrients by the fast growth of Eucalyptus. The soil nutrients in shrubland had a quick restoration rate after burning.

THE INFORMATION CONTENT OF THE FARM AND UNIT LEVEL NUTRIENT BALANCES FOR THE MANAGEMENT

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T SOMOGYI

2007-07-01

Full Text Available The farm gate balance is well known from the environmental literature. This method is not suitable in every case to show the nutrient load for the environment of agricultural companies that is the reason why unit level internal nutrient balances are applied to express the level of nutrient pollution on the environment. These also help to determine the source of the pollution. With the survey of the nutrient flows within the farm we determine the keystones of nutrient management to control the nutrient load of the pollution sources. On the basis of the results and the controlled data of the unit level internal balances we make recommendations for the most appropriate environmental policy instrument to reduce the nutrient pollution.

Nutritive value and nutrient digestibility of ensiled mango by-products

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Sompong Sruamsiri

2009-10-01

Full Text Available Mango canning by-products (seed and peel together with ensiled mango peel were subjected to analysis of dry matter (DM, ash, crude protein (CP, crude fibre (CF, ether extract (EE, nitrogen-free extract (NFE, gross energy (GE, neutral detergent fibre (NDF and acid detergent fibre (ADF. In vitro digestibility of DM (IVDMD, ADF (IVADFD and NDF (IVNDFD was determined after digesting the by-products in buffered rumen fluid for 24 or 48 h in an incubator. CP content in peel, seed and peel silage is 4.68, 4.19 and 5.27% respectively. As expected, mango seed has a higher fibre content than mango peel and peel silage as indicated by NDF (53.01 vs 25.87 and 27.56% respectively and ADF (31.02 vs 19.14 and 17.68% respectively. However, mango seed also has greater GE than mango peel and peel silage (4,070 vs 3,827 and 3,984 kcal/g DM respectively, probably due partly to its high fat content.Four head of male native cattle were used to determine nutrient digestibility of ensiled mango by-products by randomly allowing them to receive ensiled mango peel with rice straw (EMPR and different levels of Leucaena leaves. Treatments consisted of: 1 ensiled mango peel + rice straw (90:10; 2 ensiled mango peel + rice straw + Leucaena leaves (85:10:5; 3 ensiled mango peel + rice straw + Leucaena leaves (80:10:10; and 4 ensiled mango peel + rice straw + Leucaena leaves (75:10:15. Addition of Leucaena leaves to silage increased apparent digestibility of DM (53.84, 55.43, 59.04 and 58.69% for the four formulations above respectively, probably because of increasing amounts of CP from Leucaena leaves, resulting in greater digestibility of NDF (39.11, 44.47, 47.12 and 43.32% for the four formulations above respectively. Total digestible nutrients (TDN and digestible energy (DE showed the same trends as apparent digestibility of DM.

Turning the table: plants consume microbes as a source of nutrients.

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Chanyarat Paungfoo-Lonhienne

Full Text Available Interactions between plants and microbes in soil, the final frontier of ecology, determine the availability of nutrients to plants and thereby primary production of terrestrial ecosystems. Nutrient cycling in soils is considered a battle between autotrophs and heterotrophs in which the latter usually outcompete the former, although recent studies have questioned the unconditional reign of microbes on nutrient cycles and the plants' dependence on microbes for breakdown of organic matter. Here we present evidence indicative of a more active role of plants in nutrient cycling than currently considered. Using fluorescent-labeled non-pathogenic and non-symbiotic strains of a bacterium and a fungus (Escherichia coli and Saccharomyces cerevisiae, respectively, we demonstrate that microbes enter root cells and are subsequently digested to release nitrogen that is used in shoots. Extensive modifications of root cell walls, as substantiated by cell wall outgrowth and induction of genes encoding cell wall synthesizing, loosening and degrading enzymes, may facilitate the uptake of microbes into root cells. Our study provides further evidence that the autotrophy of plants has a heterotrophic constituent which could explain the presence of root-inhabiting microbes of unknown ecological function. Our discovery has implications for soil ecology and applications including future sustainable agriculture with efficient nutrient cycles.

Effects of nutrient and lime additions in mine site rehabilitation strategies on the accumulation of antimony and arsenic by native Australian plants.

Science.gov (United States)

Wilson, Susan C; Leech, Calvin D; Butler, Leo; Lisle, Leanne; Ashley, Paul M; Lockwood, Peter V

2013-10-15

The effects of nutrient and lime additions on antimony (Sb) and arsenic (As) accumulation by native Australian and naturalised plants growing in two contaminated mine site soils (2,735 mg kg(-1) and 4,517 mg kg(-1) Sb; 826 mg kg(-1) and 1606 As mgkg(-1)) was investigated using a glasshouse pot experiment. The results indicated an increase in soil solution concentrations with nutrient addition in both soils and also with nutrient+lime addition for Sb in one soil. Metalloid concentrations in plant roots were significantly greater than concentrations in above ground plant parts. The metalloid transfer to above ground plant parts from the roots and from the soil was, however, low (ratio of leaf concentration/soil concentration≪1) for all species studied. Eucalyptus michaeliana was the most successful at colonisation with lowest metalloid transfer to above ground plant parts. Addition of nutrients and nutrients+lime to soils, in general, increased plant metalloid accumulation. Relative As accumulation was greater than that of Sb. All the plant species studied were suitable for consideration in the mine soil phytostabilisation strategies but lime additions should be limited and longer term trials also recommended. Copyright © 2013 Elsevier B.V. All rights reserved.

Interação fármaco-nutriente: uma revisão Drug-nutrient interaction: a review

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Mirian Ribeiro Leite MOURA

2002-08-01

Full Text Available A dieta influencia todos os estágios do ciclo da vida, fornecendo nutrientes necessários ao sustento do corpo humano. Alterações de ordem funcional e/ou estrutural, provocadas por doenças e infecções agudas ou crônicas, levam à utilização de medicamentos, cujo objetivo é restaurar a saúde. A via preferencial escolhida para a sua administração é a oral, entre outras razões, por sua comodidade e segurança. O fenômeno de interação fármaco-nutriente pode surgir antes ou durante a absorção gastrintestinal, durante a distribuição e armazenamento nos tecidos, no processo de biotransformação ou mesmo durante a excreção. Assim, é de importância fundamental conhecer os fármacos cuja velocidade de absorção e/ou quantidade absorvida podem ser afetadas na presença de alimentos, bem como aqueles que não são afetados. Por outro lado, muitos deles, incluindo antibióticos, antiácidos e laxativos podem causar má absorção de nutrientes. Portanto, o objetivo do presente artigo é apresentar uma revisão dos diversos aspectos envolvidos na interação fármaco-nutriente.Diet influences the whole life cycle, supplying nutrients required to maintain the human body. Functional and/or structural alterations, caused by diseases and acute or chronic infections, lead to the use of drugs in order to restore the health. The oral route is preferred for drug administration, owing to safety and convenience, among other reasons. The drug-nutrient interaction phenomenon can occur before or during gastrointestinal absorption, during distribution and storage in the tissues, in the biotransformation process, or even during excretion. Thus, to know the drugs whose rate of absorption and/or absorbed amount can be affected in the presence of food, as well as those that are not affected, is of fundamental importance. On the other hand, a number of commonly used drugs, including antibiotics, antacids and laxatives, can cause malabsorption of

Proposal for a method to estimate nutrient shock effects in bacteria

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Azevedo Nuno F

2012-08-01

Full Text Available Abstract Background Plating methods are still the golden standard in microbiology; however, some studies have shown that these techniques can underestimate the microbial concentrations and diversity. A nutrient shock is one of the mechanisms proposed to explain this phenomenon. In this study, a tentative method to assess nutrient shock effects was tested. Findings To estimate the extent of nutrient shock effects, two strains isolated from tap water (Sphingomonas capsulata and Methylobacterium sp. and two culture collection strains (E. coli CECT 434 and Pseudomonas fluorescens ATCC 13525 were exposed both to low and high nutrient conditions for different times and then placed in low nutrient medium (R2A and rich nutrient medium (TSA. The average improvement (A.I. of recovery between R2A and TSA for the different times was calculated to more simply assess the difference obtained in culturability between each medium. As expected, A.I. was higher when cells were plated after the exposition to water than when they were recovered from high-nutrient medium showing the existence of a nutrient shock for the diverse bacteria used. S. capsulata was the species most affected by this phenomenon. Conclusions This work provides a method to consistently determine the extent of nutrient shock effects on different microorganisms and hence quantify the ability of each species to deal with sudden increases in substrate concentration.

Litter production and its nutrient concentration in some fuelwood trees grown on sodic soil

Energy Technology Data Exchange (ETDEWEB)

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

1992-01-01

Litter production was estimated in 8-year-old tree plantations of Acacia nilotica, Prosopis juliflora, Dalbergia sisso, and Terminalia arjuna planted in a monoculture tree cropping system on sodic soils of Lucknow Division, India. Mean annual litter fall of these trees amounted to 5.9, 7.4, 5.0 and 5.4 t ha[sup -1], respectively. Irrespective of tree species, the leaf litter concentrations of N, K and Ca were greater than those of P and Mg. The concentration of nutrients in leaf tissues was negatively correlated for N and Ca, with the magnitude of leaf fall in D. sissoo, but was positively correlated for Ca and Mg in A. nilotica; no such correlations were found in P. juliflora and T. arjuna. The variations in the concentration of leaf litter nutrient did not appear to be species specific but depended on adverse edaphic properties including the fertility status of sodic soil. A. nilotica and P. juliflora with bimodal patterns of litter fall return greater amounts of nutrients to the soil surface than D. sissoo and T. arjuna which have unimodal patterns of litter fall. The study indicated the potential benefit of a mixed plantation system having variable leaf fall patterns among the planted trees so providing constant litter mulch to help in conserving soil moisture. (author).

Diagnosis of nutrient imbalances with vector analysis in agroforestry systems.

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Isaac, Marney E; Kimaro, Anthony A

2011-01-01

Agricultural intensification has had unintended environmental consequences, including increased nutrient leaching and surface runoff and other agrarian-derived pollutants. Improved diagnosis of on-farm nutrient dynamics will have the advantage of increasing yields and will diminish financial and environmental costs. To achieve this, a management support system that allows for site-specific rapid evaluation of nutrient production imbalances and subsequent management prescriptions is needed for agroecological design. Vector diagnosis, a bivariate model to depict changes in yield and nutritional response simultaneously in a single graph, facilitates identification of nutritional status such as growth dilution, deficiency, sufficiency, luxury uptake, and toxicity. Quantitative data from cocoa agroforestry systems and pigeonpea intercropping trials in Ghana and Tanzania, respectively, were re-evaluated with vector analysis. Relative to monoculture, biomass increase in cocoa ( L.) under shade (35-80%) was accompanied by a 17 to 25% decline in P concentration, the most limiting nutrient on this site. Similarly, increasing biomass with declining P concentrations was noted for pigeonpea [ (L). Millsp.] in response to soil moisture availability under intercropping. Although vector analysis depicted nutrient responses, the current vector model does not consider non-nutrient resource effects on growth, such as ameliorated light and soil moisture, which were particularly active in these systems. We revisit and develop vector analysis into a framework for diagnosing nutrient and non-nutrient interactions in agroforestry systems. Such a diagnostic technique advances management decision-making by increasing nutrient precision and reducing environmental issues associated with agrarian-derived soil contamination. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Nutrient composition of important fish species in Bangladesh and potential contribution to recommended nutrient intakes

DEFF Research Database (Denmark)

Bogard, Jessica R.; Thilsted, Shakuntala H.; Marks, Geoffrey C.

2015-01-01

Fish, in Bangladesh where malnutrition remains a significant development challenge, is an irreplaceable animal-source food in the diet of millions. However, existing data on the nutrient composition of fish do not reflect the large diversity available and have focused on only a few select nutrien...... indigenous species, which should guide policy and programmes to improve food and nutrition security in Bangladesh....

Sensitivity analysis of a pulse nutrient addition technique for estimating nutrient uptake in large streams

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Laurence Lin; J.R. Webster

2012-01-01

The constant nutrient addition technique has been used extensively to measure nutrient uptake in streams. However, this technique is impractical for large streams, and the pulse nutrient addition (PNA) has been suggested as an alternative. We developed a computer model to simulate Monod kinetics nutrient uptake in large rivers and used this model to evaluate the...

Reducing Runoff Loss of Applied Nutrients in Oil Palm Cultivation Using Controlled-Release Fertilizers

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A. Bah

2014-01-01

Full Text Available Controlled-release fertilizers are expected to minimize nutrient loss from crop fields due to their potential to supply plant-available nutrients in synchrony with crop requirements. The evaluation of the efficiency of these fertilizers in tropical oil palm agroecological conditions is not yet fully explored. In this study, a one-year field trial was conducted to determine the impact of fertilization with water soluble conventional mixture and controlled-release fertilizers on runoff loss of nutrients from an immature oil palm field. Soil and nutrient loss were monitored for one year in 2012/2013 under erosion plots of 16 m2 on 10% slope gradient. Mean sediments concentration in runoff amounted to about 6.41 t ha−1. Conventional mixture fertilizer posed the greatest risk of nutrient loss in runoff following fertilization due to elevated nitrogen (6.97%, potassium (13.37%, and magnesium (14.76% as percentage of applied nutrients. In contrast, this risk decreased with the application of controlled-release fertilizers, representing 0.75–2.44% N, 3.55–5.09% K, and 4.35–5.43% Mg loss. Meanwhile, nutrient loss via eroded sediments was minimal compared with loss through runoff. This research demonstrates that the addition of controlled-release fertilizers reduced the runoff risks of nutrient loss possibly due to their slow-release properties.

SOIL CHEMICAL ATTRIBUTES AND LEAF NUTRIENTS OF ‘PACOVAN’ BANANA UNDER TWO COVER CROPS

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JOSÉ EGÍDIO FLORI

2016-01-01

Full Text Available Banana is one of the most consumed fruits in the world, which is grown in most tropical countries. The objective of this work was to evaluate the main attributes of soil fertility in a banana crop under two cover crops and two root development locations. The work was conducted in Curaçá, BA, Brazil, between October 2011 and May 2013, using a randomized block design in split plot with five repetitions. Two cover crops were assessed in the plots, the cover 1 consisting of Pueraria phaseoloides, and the cover 2 consisting of a crop mix with Sorghum bicolor, Ricinus communis L., Canavalia ensiformis, Mucuna aterrima and Zea mays, and two soil sampling locations in the subplots, between plants in the banana rows (location 1 and between the banana rows (location 2. There were significant and independent effects for the cover crop and sampling location factors for the variables organic matter, Ca and P, and significant effects for the interaction between cover crops and sampling locations for the variables potassium, magnesium and total exchangeable bases. The cover crop mix and the between-row location presented the highest organic matter content. Potassium was the nutrient with the highest negative variation from the initial content and its leaf content was below the reference value, however not reducing the crop yield. The banana crop associated with crop cover using the crop mix provided greater availability of nutrients in the soil compared to the coverage with tropical kudzu.

Erythroneura lawsoni abundance and feeding injury levels are influenced by foliar nutrient status in intensively managed American sycamore.

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Coyle, David, Robert: Aubrey, Doug, Patric; Bentz, Jo-Ann

2010-01-01

Abstract 1 Abundance and feeding injury of the leafhopper Erythroneura lawsoni Robinson was measured in an intensively-managed American sycamore Platanus occidentalis L. plantation. Trees were planted in spring 2000 in a randomized complete block design, and received one of three annual treatments: (i) fertilization (120 kg N/ha/year); (ii) irrigation (3.0 cm/week); (iii) fertilization + irrigation; or (iv) control (no treatment). 2 Foliar nutrient concentrations were significantly influenced by the treatments because only sulphur and manganese levels were not statistically greater in trees receiving fertilization. 3 Over 116 000 E. lawsoni were captured on sticky traps during the study. Leafhopper abundance was highest on nonfertilized trees for the majority of the season, and was positively correlated with foliar nutrient concentrations. Significant temporal variation in E. lawsoni abundance occurred, suggesting five discrete generations in South Carolina. 4 Significant temporal variation occurred in E. lawsoni foliar injury levels, with the highest injury ratings occurring in late June and August. Foliar injury was negatively correlated with foliar nutrient content, and higher levels of injury occurred more frequently on nonfertilized trees. 5 The results obtained in the present study indicated that increased E. lawsoni abundance occurred on trees that did not receive fertilization. Nonfertilized trees experienced greater foliar injury, suggesting that lower foliar nutrient status may have led to increased levels of compensatory feeding.

Biological Nutrient Removal in Compact Biofilm Systems

NARCIS (Netherlands)

Bassin, J.P.

2012-01-01

The removal of nutrients such as nitrogen and phosphorus from both domestic and industrial wastewaters is imperative since they potentially harm the environment. One of the main consequences of excessive availability of nitrogen and phosphorus in aquatic ecosystems (freshwater, marine and estuarine)

A comparison of nutrient dynamics in forest ecosystems along with the Warmth Index Gradient

International Nuclear Information System (INIS)

Iwatsubo, Goro; Li Changhua; Katagiri, Shigeo.

1993-01-01

Nutrient elements contained in litter fall flux, that of uptake flux and turnover rate had generally tended to increase with the increase in the Warmth Index, while the amount of nutrient in the A 0 horizon and nutrient use efficiency did not. However, it is suggested that topographic and climatic aridity, and the amount of available and exchangeable phosphorus, calcium and magnesium greatly affect the nutrient dynamics in a each forest ecosystem as the Warmth Index increases. (J.P.N.)

Sun-induced chlorophyll fluorescence and photochemical reflectance index improve remote-sensing gross primary production estimates under varying nutrient availability in a typical Mediterranean savanna ecosystem

Science.gov (United States)

Perez-Priego, O.; Guan, J.; Rossini, M.; Fava, F.; Wutzler, T.; Moreno, G.; Carvalhais, N.; Carrara, A.; Kolle, O.; Julitta, T.; Schrumpf, M.; Reichstein, M.; Migliavacca, M.

2015-11-01

This study investigates the performances of different optical indices to estimate gross primary production (GPP) of herbaceous stratum in a Mediterranean savanna with different nitrogen (N) and phosphorous (P) availability. Sun-induced chlorophyll fluorescence yield computed at 760 nm (Fy760), scaled photochemical reflectance index (sPRI), MERIS terrestrial-chlorophyll index (MTCI) and normalized difference vegetation index (NDVI) were computed from near-surface field spectroscopy measurements collected using high spectral resolution spectrometers covering the visible near-infrared regions. GPP was measured using canopy chambers on the same locations sampled by the spectrometers. We tested whether light-use efficiency (LUE) models driven by remote-sensing quantities (RSMs) can better track changes in GPP caused by nutrient supplies compared to those driven exclusively by meteorological data (MM). Particularly, we compared the performances of different RSM formulations - relying on the use of Fy760 or sPRI as a proxy for LUE and NDVI or MTCI as a fraction of absorbed photosynthetically active radiation (fAPAR) - with those of classical MM. Results showed higher GPP in the N-fertilized experimental plots during the growing period. These differences in GPP disappeared in the drying period when senescence effects masked out potential differences due to plant N content. Consequently, although MTCI was closely related to the mean of plant N content across treatments (r2 = 0.86, p < 0.01), it was poorly related to GPP (r2 = 0.45, p < 0.05). On the contrary sPRI and Fy760 correlated well with GPP during the whole measurement period. Results revealed that the relationship between GPP and Fy760 is not unique across treatments, but it is affected by N availability. Results from a cross-validation analysis showed that MM (AICcv = 127, MEcv = 0.879) outperformed RSM (AICcv =140, MEcv = 0.8737) when soil moisture was used to constrain the seasonal dynamic of LUE. However

Export of nutrients from golf courses on the Precambrian Shield

International Nuclear Information System (INIS)

Winter, Jennifer G.; Dillon, Peter J.

2006-01-01

Annual export rates, or fluxes, of total nitrogen (TN), nitrate, total phosphorus (TP) and potassium from four streams on two golf courses on the Precambrian Shield were compared with those from forested reference locations. Overall, the mean annual fluxes of K, TN, NO 3 and TP from golf courses were greater than from forested areas by 10, 2, 6 and 2 times, respectively. The overall mean export coefficients (kg/ha/yr) were 16 for K, 5.2 for TN, 2.1 for NO 3 and 0.14 for TP. For TN and TP, these are similar to those reported from cropland in Canada by Chambers and Dale (1997. Contribution of industrial, municipal, agricultural and groundwater sources to nutrient export, Athabasca, Wapiti and Smoky Rivers, 1980 to 1993. Northern River Basins Study Project Report No. 110. Northern River Basins Study, Edmonton, Alberta). -- Golf courses increase nutrient loads in receiving streams

Nutrient Administration and Resistance Training

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Leutholtz Brian

2005-06-01

Full Text Available Abstract Skeletal muscle tissue is tightly regulated throughout our bodies by balancing its synthesis and breakdown. Many factors are known to exist that cause profound changes on the overall status of skeletal muscle, some of which include exercise, nutrition, hormonal influences and disease. Muscle hypertrophy results when protein synthesis is greater than protein breakdown. Resistance training is a popular form of exercise that has been shown to increase muscular strength and muscular hypertrophy. In general, resistance training causes a stimulation of protein synthesis as well as an increase in protein breakdown, resulting in a negative balance of protein. Providing nutrients, specifically amino acids, helps to stimulate protein synthesis and improve the overall net balance of protein. Strategies to increase the concentration and availability of amino acids after resistance exercise are of great interest and have been shown to effectively increase overall protein synthesis. 123 After exercise, providing carbohydrate has been shown to mildly stimulate protein synthesis while addition of free amino acids prior to and after exercise, specifically essential amino acids, causes a rapid pronounced increase in protein synthesis as well as protein balance.13 Evidence exists for a dose-response relationship of infused amino acids while no specific regimen exists for optimal dosing upon ingestion. Ingestion of whole or intact protein sources (e.g., protein powders, meal-replacements has been shown to cause similar improvements in protein balance after resistance exercise when compared to free amino acid supplements. Future research should seek to determine optimal dosing of ingested intact amino acids in addition to identifying the cellular mechanistic machinery (e.g. transcriptional and translational mechanisms for causing the increase in protein synthesis.

Suitability of macrophytes for nutrient removal from surface flow constructed wetlands receiving secondary treated sewage effluent in Queensland, Australia.

Science.gov (United States)

Greenway, M

2003-01-01

From a botanical perspective the major difference between waste stabilisation ponds and wetlands is the dominance of algae or floating plants in the former and emergent plants in the latter. Algae, floating and submerged plants remove nutrients directly from the water column whereas emergent species remove nutrients from the sediment. Water depth is a crucial factor in determining which plant types will become established. Surface flow constructed wetlands offer the greatest potential to grow a wide variety of different types of macrophytes. In assessing the suitability of plant species for nutrient removal, consideration must be given not only to nutrient uptake for growth but also storage of nutrients as plant biomass. A survey of macrophytes in 15 surface flow constructed wetlands treating secondary effluent was conducted in Queensland; 63 native species and 14 introduced species were found. Emergent species have been able to tolerate deeper water than in their natural environment and permanent waterlogging. All species grew well in the higher nutrient enriched wastewater. Submerged, floating leaved-attached and free floating species had the highest tissue nutrient content, followed by aquatic creepers. All these species remove nutrients from the water column. Emergent species had lower nutrient content but a greater biomass and were therefore able to store more nutrients per unit area of wetland. In order to maximise the efficiency of constructed wetlands for nutrient removal, a range of species should be used. Native species should be selected in preference to introduced/exotic species.

Interactions between temperature and nutrients across levels of ecological organization.

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Cross, Wyatt F; Hood, James M; Benstead, Jonathan P; Huryn, Alexander D; Nelson, Daniel

2015-03-01

Temperature and nutrient availability play key roles in controlling the pathways and rates at which energy and materials move through ecosystems. These factors have also changed dramatically on Earth over the past century as human activities have intensified. Although significant effort has been devoted to understanding the role of temperature and nutrients in isolation, less is known about how these two factors interact to influence ecological processes. Recent advances in ecological stoichiometry and metabolic ecology provide a useful framework for making progress in this area, but conceptual synthesis and review are needed to help catalyze additional research. Here, we examine known and potential interactions between temperature and nutrients from a variety of physiological, community, and ecosystem perspectives. We first review patterns at the level of the individual, focusing on four traits--growth, respiration, body size, and elemental content--that should theoretically govern how temperature and nutrients interact to influence higher levels of biological organization. We next explore the interactive effects of temperature and nutrients on populations, communities, and food webs by synthesizing information related to community size spectra, biomass distributions, and elemental composition. We use metabolic theory to make predictions about how population-level secondary production should respond to interactions between temperature and resource supply, setting up qualitative predictions about the flows of energy and materials through metazoan food webs. Last, we examine how temperature-nutrient interactions influence processes at the whole-ecosystem level, focusing on apparent vs. intrinsic activation energies of ecosystem processes, how to represent temperature-nutrient interactions in ecosystem models, and patterns with respect to nutrient uptake and organic matter decomposition. We conclude that a better understanding of interactions between temperature and

Properties of biochar derived from wood and high-nutrient biomasses with the aim of agronomic and environmental benefits.

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Rimena R Domingues

Full Text Available Biochar production and use are part of the modern agenda to recycle wastes, and to retain nutrients, pollutants, and heavy metals in the soil and to offset some greenhouse gas emissions. Biochars from wood (eucalyptus sawdust, pine bark, sugarcane bagasse, and substances rich in nutrients (coffee husk, chicken manure produced at 350, 450 and 750°C were characterized to identify agronomic and environmental benefits, which may enhance soil quality. Biochars derived from wood and sugarcane have greater potential for improving C storage in tropical soils due to a higher aromatic character, high C concentration, low H/C ratio, and FTIR spectra features as compared to nutrient-rich biochars. The high ash content associated with alkaline chemical species such as KHCO3 and CaCO3, verified by XRD analysis, made chicken manure and coffee husk biochars potential liming agents for remediating acidic soils. High Ca and K contents in chicken manure and coffee husk biomass can significantly replace conventional sources of K (mostly imported in Brazil and Ca, suggesting a high agronomic value for these biochars. High-ash biochars, such as chicken manure and coffee husk, produced at low-temperatures (350 and 450°C exhibited high CEC values, which can be considered as a potential applicable material to increase nutrient retention in soil. Therefore, the agronomic value of the biochars in this study is predominantly regulated by the nutrient richness of the biomass, but an increase in pyrolysis temperature to 750°C can strongly decrease the adsorptive capacities of chicken manure and coffee husk biochars. A diagram of the agronomic potential and environmental benefits is presented, along with some guidelines to relate biochar properties with potential agronomic and environmental uses. Based on biochar properties, research needs are identified and directions for future trials are delineated.

Nutrient acquisition strategies of mammalian cells.

Science.gov (United States)

Palm, Wilhelm; Thompson, Craig B

2017-06-07

Mammalian cells are surrounded by diverse nutrients, such as glucose, amino acids, various macromolecules and micronutrients, which they can import through transmembrane transporters and endolysosomal pathways. By using different nutrient sources, cells gain metabolic flexibility to survive periods of starvation. Quiescent cells take up sufficient nutrients to sustain homeostasis. However, proliferating cells depend on growth-factor-induced increases in nutrient uptake to support biomass formation. Here, we review cellular nutrient acquisition strategies and their regulation by growth factors and cell-intrinsic nutrient sensors. We also discuss how oncogenes and tumour suppressors promote nutrient uptake and thereby support the survival and growth of cancer cells.

Food Sources of Total Energy and Nutrients among U.S. Infants and Toddlers: National Health and Nutrition Examination Survey 2005–2012

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Carley A. Grimes

2015-08-01

Full Text Available Understanding the dietary intakes of infants and toddlers is important because early life nutrition influences future health outcomes. The aim of this study was to determine the dietary sources of total energy and 16 nutrients in a nationally representative sample of U.S. infants and toddlers aged 0–24 months. Data from the 2005–2012 National Health and Nutrition Examination Survey were analyzed. Dietary intake was assessed in 2740 subjects using one 24-h dietary recall. The population proportion was used to determine the contribution of foods and beverages to nutrient intakes. Overall infant formulas and baby foods were the leading sources of total energy and nutrients in infants aged 0–11.9 months. In toddlers, the diversity of food groups contributing to nutrient intakes was much greater. Important sources of total energy included milk, 100% juice and grain based mixed dishes. A number of foods of low nutritional quality also contributed to energy intakes including sweet bakery products, sugar-sweetened beverages and savory snacks. Overall non-flavored milks and ready-to-eat cereals were the most important contributors to micronutrient intakes. In conclusion this information can be used to guide parents regarding appropriate food selection as well as inform targeted dietary strategies within public health initiatives to improve the diets of infants and toddlers.

Combined effects of water, nutrient, and UV-B stress on female fitness in Brassica (Brassicaceae)

International Nuclear Information System (INIS)

Conner, J.K.; Zangori, L.A.

1998-01-01

Our knowledge of the effects of increased levels of ultraviolet-B radiation (UV-B) on plant fitness is limited mainly to yield studies in a few crop species. Previous greenhouse and garden studies of Brassica have found greater detrimental effects of UV-B on fitness in gardens than in the greenhouse, suggesting the possibility that additional stresses in the field decrease the ability of Brassica to cope with UV-B. Possible interactions between UV-B and water/nutrient stress in determining plant fitness have rarely, if ever, been studied experimentally. Here we report measurements of female fitness in two species of Brassica in an experiment in which both UV-B and levels of water and nutrients were varied in a 2 X 2 factorial design. Water and nutrient stress reduced female fitness in both species, while UV-B caused fitness reductions in only one of the species. There was evidence for interactions between UV-B and water/nutrient stress for only a few of the traits measured; most traits, including those closely related to fitness, showed no evidence of an interaction

NUTRIENT BALANCE IN WATER HARVESTING SOILS

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Díaz, F

2005-05-01

Full Text Available Dryland farming on Fuerteventura and Lanzarote (Canary Islands, Spain, which has an annual rainfall of less than 150 mm/year, has been based traditionally on water harvesting techniques (known locally as “gavias”. Periods of high productivity alternate with those of very low yield. The systems are sustainable in that they reduce erosive processes, contribute to soil and soil-water conservation and are largely responsible for maintaining the soil’s farming potential. In this paper we present the chemical fertility status and nutrient balance of soils in five “gavia” systems. The results are compared with those obtained in adjacent soils where this water harvesting technique is not used. The main crops are wheat, barley, maize, lentils and chick-peas. Since neither organic nor inorganic fertilisers are used, nutrients are derived mainly from sediments carried by runoff water. Nutrients are lost mainly through crop harvesting and harvest residues. The soils where water harvesting is used have lower salt and sodium in the exchange complex, are higher in carbon, nitrogen, copper and zinc and have similar phosphorous and potassium content. It is concluded that the systems improve the soil’s natural fertility and also that natural renovation of nutrients occurs thanks to the surface deposits of sediments, which mix with the arable layer. The system helps ensure adequate fertility levels, habitual in arid regions, thus allowing dryland farming to be carried out.

Nutrient and Organic Carbon Losses, Enrichment Rate, and Cost of Water Erosion

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Ildegardis Bertol

Full Text Available ABSTRACT Soil erosion from water causes loss of nutrients and organic carbon, enriches the environment outside the erosion site, and results in costs. The no-tillage system generates increased nutrient and C content in the topsoil and, although it controls erosion, it can produce a more enriched runoff than in the conventional tillage system. This study was conducted in a Humic Cambisol in natural rainfall from 1997 to 2012 to quantify the contents and total losses of nutrients and organic C in soil runoff, and to calculate the enrichment rates and the cost of these losses. The treatments evaluated were: a soil with a crop, consisting of conventional tillage with one plowing + two harrowings (CT, minimum tillage with one chisel plowing + one harrowing (MT, and no tillage (NT; and b bare soil: one plowing + two harrowings (BS. In CT, MT, and NT, black oat, soybean, vetch, corn, turnip, and black beans were cultivated. Over the 15 years, 15.5 Mg ha-1 of limestone, 525 kg ha-1 of N (urea, 1,302 kg ha-1 of P2O5 (triple superphosphate, and 1,075 kg ha-1 of K2O (potassium chloride were used in the soil. The P, K, Ca, Mg, and organic C contents in the soil were determined and also the P, K, Ca, and Mg sediments in the runoff water. From these contents, the total losses, the enrichment rates (ER, and financial losses were calculated. The NT increased the P, K, and organic C contents in the topsoil. The nutrients and organic C content in the runoff from NT was greater than from CT, showing that NT was not a fully conservationist practice for soil. The linear model y = a + bx fit the data within the level of significance (p≤0.01 when the values of P, K, and organic C in the sediments from erosion were related to those values in the soil surface layer. The nutrient and organic C contents were higher in the sediments from erosion than in the soil where the erosion originated, generating values of ER>1 for P, K, and organic C. The value of the total losses

Human skin condition and its associations with nutrient concentrations in serum and diet

NARCIS (Netherlands)

Boelsma, E.; Vijver, L.P.L. van de; Goldbohm, R.A.; Klöpping-Ketelaars, I.A.A.; Hendriks, H.F.J.; Roza, L.

2003-01-01

Background: Nutritional factors exert promising actions on the skin, but only scant information is available on the modulating effects of physiologic concentrations of nutrients on the skin condition of humans. Objective: The objective was to evaluate whether nutrient concentrations in serum and

A nutrient dependant switch explains mutually exclusive existence of meiosis and mitosis initiation in budding yeast.

Science.gov (United States)

Wannige, C T; Kulasiri, D; Samarasinghe, S

2014-01-21

Nutrients from living environment are vital for the survival and growth of any organism. Budding yeast diploid cells decide to grow by mitosis type cell division or decide to create unique, stress resistant spores by meiosis type cell division depending on the available nutrient conditions. To gain a molecular systems level understanding of the nutrient dependant switching between meiosis and mitosis initiation in diploid cells of budding yeast, we develop a theoretical model based on ordinary differential equations (ODEs) including the mitosis initiator and its relations to budding yeast meiosis initiation network. Our model accurately and qualitatively predicts the experimentally revealed temporal variations of related proteins under different nutrient conditions as well as the diverse mutant studies related to meiosis and mitosis initiation. Using this model, we show how the meiosis and mitosis initiators form an all-or-none type bistable switch in response to available nutrient level (mainly nitrogen). The transitions to and from meiosis or mitosis initiation states occur via saddle node bifurcation. This bidirectional switch helps the optimal usage of available nutrients and explains the mutually exclusive existence of meiosis and mitosis pathways. © 2013 Elsevier Ltd. All rights reserved.

Comparing the functional components, SOD-like activities, antimutagenicity, and nutrient compositions of Phellinus igniarius and Phellinus linteus mushrooms

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Nae-Cherng Yang

2016-04-01

Full Text Available Many species of the genus Phellinus possess beneficial properties, including antioxidant, immune-enhancing, and antimutagenic effects. Phenolic compounds and polysaccharides are two kinds of bioactive compounds; however, few studies have compared the differences between Phellinus igniarius and Phellinus linteus in their functional components, functional activities, and nutrient compositions. Herein, the proximate compositions and microelements of the fruiting body of P. igniarius and P. linteus were determined. The fruiting body of P. igniarius and P. linteus were extracted by boiling water [water extract of P. igniarius (WEPI and P. linteus (WEPL]. The contents of total phenolics and polysaccharides, as well as superoxide dismutase (SOD-like and antimutagenic activities of WEPI and WEPL, were compared. We found that WEPI was rich in phenolics and polysaccharides and had higher SOD-like activity than WEPL. Nutrient compositions were mainly different in minerals, whereas anitmutagenicity was similar. All of these results suggested that P. igniarius has greater potential for the development of antioxidant and immunomodulating food products than P. linteus.

Growth, allocation and tissue chemistry of Picea abies seedlings affected by nutrient supply during the second growing season.

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Kaakinen, Seija; Jolkkonen, Annika; Iivonen, Sari; Vapaavuori, Elina

2004-06-01

One-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were grown hydroponically in a growth chamber to investigate the effects of low and high nutrient availability (LN; 0.25 mM N and HN; 2.50 mM N) on growth, biomass allocation and chemical composition of needles, stem and roots during the second growing season. Climatic conditions in the growth chamber simulated the mean growing season from May to early October in Flakaliden, northern Sweden. In the latter half of the growing season, biomass allocation changed in response to nutrient availability: increased root growth and decreased shoot growth led to higher root/shoot ratios in LN seedlings than in HN seedlings. At high nutrient availability, total biomass, especially stem biomass, increased, as did total nonstructural carbohydrate and nitrogen contents per seedling. Responses of stem chemistry to nutrient addition differed from those of adult trees of the same provenance. In HN seedlings, concentrations of alpha-cellulose, hemicellulose and lignin decreased in the secondary xylem. Our results illustrate the significance of retranslocation of stored nutrients to support new growth early in the season when root growth and nutrient uptake are still low. We conclude that nutrient availability alters allocation patterns, thereby influencing the success of 2-year-old Norway spruce seedlings at forest planting sites.

The influence of dietary and whole-body nutrient content on the excretion of a vertebrate consumer.

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Christopher M Dalton

Full Text Available In many contexts, nutrient excretion by consumers can impact ecosystems by altering the availability of limiting nutrients. Variation in nutrient excretion can be predicted by mass balance models, most of which are premised on two key ideas: (1 consumers maintain fixed whole-body nutrient content (i.e., %N and %P, so-called fixed homeostasis; (2 if dietary nutrients are not matched to whole-body nutrients, excesses of any nutrient are released as excretion to maintain fixed homeostasis. Mass balance models thus predict that consumer excretion should be positively correlated with diet nutrients and negatively correlated with whole-body nutrients. Recent meta-analyses and field studies, however, have often failed to find these expected patterns, potentially because of a confounding influence-flexibility in whole-body nutrient content with diet quality (flexible homeostasis. Here, we explore the impact of flexible homeostasis on nutrient excretion by comparing the N and P excretion of four genetically diverged Trinidadian guppy (Poecilia reticulata populations when reared on diets of variable P content. As predicted by mass balance, P excretion increased on the high-P diet, but, contrary to the notion of fixed homeostasis, guppy whole-body %P also increased on the high-P diet. While there was no overall correlation between excretion nutrients and whole-body nutrients, when the effect of diet on both whole-body and excretion nutrients was included, we detected the expected negative correlation between whole-body N:P and excretion N:P. This last result suggests that mass balance can predict excretion rates within species, but only if dietary effects on whole-body nutrient content are controlled. Flexible homeostasis can obscure patterns predicted by mass balance, creating an imperative to accurately capture an organism's diet quality in predicting its excretion rate.

Seasonal changes in temperature and nutrient control of photosynthesis, respiration and growth of natural phytoplankton communities

DEFF Research Database (Denmark)

Stæhr, P. A.; Sand-Jensen, K.

2006-01-01

cultures in seasons of low ambient nutrient availability. 3. Temperature stimulation of growth and metabolism was higher at low than high ambient temperature showing that long-term temperature acclimation of the phytoplankton community before the experiments was of great importance for the measured rates...... +2, +4 and +6 °C for 2 weeks with and without addition of extra inorganic nutrients. 2. Rates of photosynthesis, respiration and growth generally increased with temperature, but this effect was strongly enhanced by high nutrient availability, and therefore was most evident for nutrient amended......1. To investigate the influence of elevated temperatures and nutrients on photosynthesis, respiration and growth of natural phytoplankton assemblages, water was collected from a eutrophic lake in spring, summer, autumn, winter and the following spring and exposed to ambient temperature and ambient...

Nutrient sequestration in Aquitaine lakes (SW France) limits nutrient flux to the coastal zone

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Buquet, Damien; Anschutz, Pierre; Charbonnier, Céline; Rapin, Anne; Sinays, Rémy; Canredon, Axel; Bujan, Stéphane; Poirier, Dominique

2017-12-01

Oligotrophic coastal zones are disappearing from increased nutrient loading. The quantity of nutrients reaching the coast is determined not only by their original source (e.g. fertilizers used in agriculture, waste water discharges) and the land use, but also by the pathways through which nutrients are cycled from the source to the river mouth. In particular, lakes sequester nutrients and, hence, reduce downstream transfer of nutrients to coastal environments. Here, we quantify the impact of Aquitaine great lakes on the fluxes of dissolved macro-nutrients (N, P, Si) to the Bay of Biscay. For that, we have measured nutrient concentrations and fluxes in 2014 upstream and downstream lakes of Lacanau and Carcans-Hourtin, which belongs to the catchment of the Arcachon Bay, which is the largest coastal lagoon of the Bay of Biscay French coast. Data were compared to values obtained from the Leyre river, the main freshwater and nutrient source for the lagoon. Results show that processes in lakes greatly limit nutrient flux to the lagoon compared to fluxes from Leyre river, although the watershed is similar in terms of land cover. In lakes, phosphorus and silicon are trapped for long term in the sediment, silicon as amorphous biogenic silica and phosphorus as organic P and P associated with Fe-oxides. Nitrogen that enters lakes mostly as nitrate is used for primary production. N is mineralized in the sediment; a fraction diffuses as ammonium. N2 production through benthic denitrification extracts only 10% of dissolved inorganic nitrogen from the aquatic system. The main part is sequestered in organic-rich sediment that accumulates below 5 m depth in both lakes.

Increased Sporulation of Vesicular-Arbuscular Mycorrhizal Fungi by Manipulation of Nutrient Regimens †

OpenAIRE

Douds, David D.; Schenck, N. C.

1990-01-01

Adjustment of pot culture nutrient solutions increased root colonization and sporulation of vesicular-arbuscular mycorrhizal (VAM) fungi. Paspalum notatum Flugge and VAM fungi were grown in a sandy soil low in N and available P. Hoagland nutrient solution without P enhanced sporulation in soil and root colonization of Acaulospora longula, Scutellospora heterogama, Gigaspora margarita, and a wide range of other VAM fungi over levels produced by a tap water control or nutrient solutions contain...

Effects of Increased Nitrogen Availability on C and N Cycles in Tropical Forests: A Meta-Analysis

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2015-01-01

Atmospheric N deposition is predicted to increase four times over its current status in tropical forests by 2030. Our ability to understand the effects of N enrichment on C and N cycles is being challenged by the large heterogeneity of the tropical forest biome. The specific response will depend on the forest’s nutrient status; however, few studies of N addition appear to incorporate the nutrient status in tropical forests, possibly due to difficulties in explaining how this status is maintained. We used a meta-analysis to explore the consequences of the N enrichment on C and N cycles in tropical montane and lowland forests. We tracked changes in aboveground and belowground plant C and N and in mineral soil in response to N addition. We found an increasing trend of plant biomass in montane forests, but not in lowland forests, as well as a greater increase in NO emission in montane forest compared with lowland forest. The N2O and NO emission increase in both forest; however, the N2O increase in lowland forest was significantly even at first time N addition. The NO emission increase showed be greater at first term compared with long term N addition. Moreover, the increase in total soil N, ammonium, microbial N, and dissolved N concentration under N enrichment indicates a rich N status of lowland forests. The available evidence of N addition experiments shows that the lowland forest is richer in N than montane forests. Finally, the greater increase in N leaching and N gas emission highlights the importance of study the N deposition effect on the global climate change. PMID:26633681

Essential nutrient requirements of the elderly

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Skully R

2014-06-01

Full Text Available Robert Skully Department of Family Medicine, Grant Medical Center, OhioHealth, Columbus, OH, USA Abstract: Government-sponsored medical organizations in developed countries have established guidelines for daily nutritional requirements. For most nutrients there is general agreement surrounding these requirements, which are based on exhaustive scientific literature review. Differences in these recommendations exist because of genetic and environmental factors that result in differences in disease susceptibility, but also due to incomplete understanding of the roles of nutrients in disease prevention. This review briefly summarizes nutrient recommendations for older adults such as where those recommendations differ from those of younger adults; and includes areas of developing understanding such as the possible role of thiamine deficiency in patients with congestive heart failure, the need for some older adults to ingest absorbable forms of vitamin B12, the high prevalence of vitamin D deficiency, the potential role of vitamin K in bone health, the need for higher levels of protein intake in order to stimulate muscle protein synthesis as one ages, the role of calcium in osteoporosis, and the possible need for zinc supplementation in hospitalized patients. Keywords: vitamins, nutritional requirements, energy expenditure, energy consumption

Bacterioplankton Community Dynamics and Nutrient Availability in a Shallow Well Mixed Estuary of the Northern Gulf of Mexico.

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Hoch, M. P.

2016-02-01

Sabine Lake Estuary is a shallow, well mixed, tidal lagoon of the Northern Gulf of Mexico. This study defines the bacterioplankton community composition and factors that may influence its variation in Sabine Lake Estuary. Twenty physicochemical parameters, phytoplankton photopigments, and bacterial 16SrDNA sequences were analyzed seasonally from twelve sites ranging from the inflows of Sabine and Neches Rivers to the Sabine Pass outflow. Photopigments were used to estimate phytoplankton groups via CHEMTAX, and bacterioplankton 16SrDNA sequences of 97% similarity were quantified and taxa identified. Nutrient availability experiments were conducted on bacterioplankton. Notable seasonal differences were seen in six of the ten most common (>3% of total sequences) classes of bacterioplankton. Canonical correspondence analysis (CCA) of common classes was used to explore physiochemical parameters and phytoplankton groups influencing variation in the bacterioplankton. Alphaproteobacteria were most abundant throughout the year. Opitutae, Actinobacteria, Sphingobacteria, and Beta-proteobacteria were strongly influenced by conditions with higher TDN, DOC, turbidity, and Chlorophytes during winter when high river discharges reduced salinity. Planctomycetacia were most prevalent during spring and coincide with predominance of Cryptophytes. In summer and fall the aforementioned classes decline, and there is an increase in Synechococcophycideae. Nitrogen was least available to bacterioplankton during summer and fall. Clearer, warmer and more saline conditions with lower DOC reflect tidal movement of seawater into the estuary when river discharges were low, conditions favorable for Synechococcophycidea. Seasonal fluctuations in physicochemical conditions and certain phytoplankton groups influence the variation in the bacterioplankton community in Sabine Lake Estuary.

Intake, nutrient apparent digestibility and ruminal constituents of sheep fed diets with canola, sunflower or castor oils

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Michelle de Oliveira Maia

2012-11-01

Full Text Available The objective in this experiment was to determine the effects of feeding diets with canola, sunflower or castor oils on intake, nutrient apparent digestibility and ruminal constituents of crossbred Dorper × Santa Inês sheep. Four rumen-cannulated animals of 90.2±11.4 kg average body weight were assigned to a 4 × 4 latin square. Animals remained individually in cages for the metabolism assay and were fed diets containing roughage at 500 g/kg and concentrate based on ground corn and soybean meal also at 500 g/kg. No oil was added to the control diet, whereas the others had canola, sunflower or castor oils at 30 g/kg (DM basis. There was no difference for the intake of DM and nutrients, except for ether extract, which was greater when animals received oil. The digestibility coefficients of dry matter, organic matter, crude protein, non-fiber carbohydrates and neutral detergent fiber were not changed; however, the addition of oil increased the ether extract digestibility. The values of total digestible nutrients (TDN, g/kg of DM, digestible energy (DE, Mcal/kg of DM, TDN intake and DE intake also did not change with the addition of lipids. Concerning the ruminal constituents, the addition of vegetable oils reduced the concentrations of acetate, butyrate and total short-chain fatty acids. Adding canola, sunflower or castor oils at 30 g/kg in diets with 500 g roughage/kg and 500 g concentrate/kg does not impair the intake or digestibility of nutrients in sheep, although it reduces the concentration of short-chain fatty acids in the rumen.

Nutrient Management in Recirculating Hydroponic Culture

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Bugbee, Bruce

2004-01-01

There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

Nutrient density of beverages in relation to climate impact

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Annika Smedman

2010-08-01

Full Text Available The food chain contributes to a substantial part of greenhouse gas (GHG emissions and growing evidence points to the urgent need to reduce GHGs emissions worldwide. Among suggestions were proposals to alter food consumption patterns by replacing animal foods with more plant-based foods. However, the nutritional dimensions of changing consumption patterns to lower GHG emissions still remains relatively unexplored. This study is the first to estimate the composite nutrient density, expressed as percentage of Nordic Nutrition Recommendations (NNR for 21 essential nutrients, in relation to cost in GHG emissions of the production from a life cycle perspective, expressed in grams of CO2-equivalents, using an index called the Nutrient Density to Climate Impact (NDCI index. The NDCI index was calculated for milk, soft drink, orange juice, beer, wine, bottled carbonated water, soy drink, and oat drink. Due to low-nutrient density, the NDCI index was 0 for carbonated water, soft drink, and beer and below 0.1 for red wine and oat drink. The NDCI index was similar for orange juice (0.28 and soy drink (0.25. Due to a very high-nutrient density, the NDCI index for milk was substantially higher (0.54 than for the other beverages. Future discussion on how changes in food consumption patterns might help avert climate change need to take both GHG emission and nutrient density of foods and beverages into account.

Nutrient-dependent/pheromone-controlled adaptive evolution: a model

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James Vaughn Kohl

2013-06-01

Full Text Available Background: The prenatal migration of gonadotropin-releasing hormone (GnRH neurosecretory neurons allows nutrients and human pheromones to alter GnRH pulsatility, which modulates the concurrent maturation of the neuroendocrine, reproductive, and central nervous systems, thus influencing the development of ingestive behavior, reproductive sexual behavior, and other behaviors. Methods: This model details how chemical ecology drives adaptive evolution via: (1 ecological niche construction, (2 social niche construction, (3 neurogenic niche construction, and (4 socio-cognitive niche construction. This model exemplifies the epigenetic effects of olfactory/pheromonal conditioning, which alters genetically predisposed, nutrient-dependent, hormone-driven mammalian behavior and choices for pheromones that control reproduction via their effects on luteinizing hormone (LH and systems biology. Results: Nutrients are metabolized to pheromones that condition behavior in the same way that food odors condition behavior associated with food preferences. The epigenetic effects of olfactory/pheromonal input calibrate and standardize molecular mechanisms for genetically predisposed receptor-mediated changes in intracellular signaling and stochastic gene expression in GnRH neurosecretory neurons of brain tissue. For example, glucose and pheromones alter the hypothalamic secretion of GnRH and LH. A form of GnRH associated with sexual orientation in yeasts links control of the feedback loops and developmental processes required for nutrient acquisition, movement, reproduction, and the diversification of species from microbes to man. Conclusion: An environmental drive evolved from that of nutrient ingestion in unicellular organisms to that of pheromone-controlled socialization in insects. In mammals, food odors and pheromones cause changes in hormones such as LH, which has developmental affects on pheromone-controlled sexual behavior in nutrient-dependent reproductively

The nutrient value of Imbrasia belina Lepidoptera: Saturnidae (madora).

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Onigbinde, A O; Adamolekun, B

1998-05-01

To determine the pattern of consumption of Imbrasia belina (madora) and other edible insects and also compare the nutrient values of madora larvae and two of its variants (Anaphe venata and Cirina forda) to those of some conventional sources of protein. University of Zimbabwe. 100 workers who admitted to a history of entomophagy. Popularity score of madora compared with those of other edible insects and approximate compositions of nutrients in the larvae compared with standard proteins. Most respondents (65%) were introduced to entomophagy by their parents. Termites were the most frequently consumed, followed by madora. More respondents ate insects because of their perceived nutritional value than because of their relative availability. There was no association of entomophagy with significant side effects. The protein, fat and mineral contents of the larvae were superior to those of beef and chicken. There were no major differences in the nutrient composition of the three Lepidoptera variants. The high nutrient value and low cost of these larvae make them an important protein supplement, especially for people in the low income group.

Determination of the algal growth-limiting nutrients in strip mine ponds

International Nuclear Information System (INIS)

Bucknavage, M.J.; Aharrah, E.C.

1984-01-01

Using both a test organism, Ankistrodesmus falcatus, and natural phytoplankton, the Printz Algal Assay Bottle Test was used to determine the algal growth limiting nutrients in two strip mine ponds. Nitrogen, phosphorus, and iron were investigated, singly and in combination, as possible limiting nutrients. A synthetic chelator, Na 2 EDTA, was also used in the assay to test for the presence of metal toxicants and/or trace metal limitation. Because bacteria have a major influence on water chemistry, a separate assay incorporating the natural bacteria population was performed. In both ponds, assay results using test alga indicate phosphorus to be the primary limiting nutrient and nitrogen as a secondary factor. The presence of EDTA in combination with phosphate containing treatment promoted a higher algal concentration in both ponds. Iron was determined to be a secondary limiting nutrient in only one of the ponds. Natural phytoplankton of the two ponds responded in a similar manner to nutrient increases. Only one pond had the same results produced by both assays. Nutrient availability was influenced by the presence of bacteria in one pond but not in the other

Contribution of fish farming to the nutrient loading of the Mediterranean

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Ioannis Karakassis

2005-06-01

Full Text Available Mediterranean fish farming has grown exponentially during the last 20 years. Although there is little evidence of the impact on the trophy status around fish farms, there are concerns that the release of solute wastes from aquaculture might affect larger scales in the ecosystem by changing the nutrient load. After combining information from various sources on waste production and on nutrient loads, it was concluded that the overall N and P waste from fish farms in the Mediterranean represents less than 5% of the total annual anthropogenic discharge, and the overall annual increase in P and N pools in the Mediterranean, under a production rate of 150000 tons, is less than 0.01%. The proportion of fish farming discharged nutrients was slightly higher in the eastern Mediterranean. A simple model was used to assess the long-term effects of nutrients released from various sources taking into account the water renewal rate in the Mediterranean. We conclude that, in the long term, fish farm waste could cause a 1% increase in nutrient concentrations in contrast to other anthropogenic activities which might double the Mediterranean nutrient pool.

Phloem small RNAs, nutrient stress responses, and systemic mobility

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Kehr Julia

2010-04-01

Full Text Available Abstract Background Nutrient availabilities and needs have to be tightly coordinated between organs to ensure a balance between uptake and consumption for metabolism, growth, and defense reactions. Since plants often have to grow in environments with sub-optimal nutrient availability, a fine tuning is vital. To achieve this, information has to flow cell-to-cell and over long-distance via xylem and phloem. Recently, specific miRNAs emerged as a new type of regulating molecules during stress and nutrient deficiency responses, and miR399 was suggested to be a phloem-mobile long-distance signal involved in the phosphate starvation response. Results We used miRNA microarrays containing all known plant miRNAs and a set of unknown small (s RNAs earlier cloned from Brassica phloem sap 1, to comprehensively analyze the phloem response to nutrient deficiency by removing sulfate, copper or iron, respectively, from the growth medium. We show that phloem sap contains a specific set of sRNAs that is distinct from leaves and roots, and that the phloem also responds specifically to stress. Upon S and Cu deficiencies phloem sap reacts with an increase of the same miRNAs that were earlier characterized in other tissues, while no clear positive response to -Fe was observed. However, -Fe led to a reduction of Cu- and P-responsive miRNAs. We further demonstrate that under nutrient starvation miR399 and miR395 can be translocated through graft unions from wild type scions to rootstocks of the miRNA processing hen1-1 mutant. In contrast, miR171 was not transported. Translocation of miR395 led to a down-regulation of one of its targets in rootstocks, suggesting that this transport is of functional relevance, and that miR395, in addition to the well characterized miR399, could potentially act as a long-distance information transmitter. Conclusions Phloem sap contains a specific set of sRNAs, of which some specifically accumulate in response to nutrient deprivation. From

Nutrient solution and substrates for ‘cedro doce’ (Pochota fendleri seedling production

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Oscar J. Smiderle

Full Text Available ABSTRACT This study assessed the effect of different substrates and addition of nutrient solution on the production of Pochota fendleri seedlings, leaf contents of macro and micronutrients and chlorophyll a and b. The experimental design was completely randomized, in a 3 x 2 factorial scheme, with four replicates. The factors were three substrates, with or without addition of nutrient solution, composing six treatments: (T1 = sand; (T2 = soil; (T3 = sand + soil (1:1; (T4 = sand + nutrient solution; (T5 = soil + nutrient solution; (T6 = sand + soil + nutrient solution. Growth characteristics (height, collar diameter, shoot dry matter, root dry matter, root/shoot ratio and total dry matter and contents of macro- and micronutrients and chlorophyll a and b were evaluated. The use of nutrient solution reduces the time to obtain seedlings of Pochota fendleri, and it is important for proper growth and quality of seedlings. The sequence of nutritional requirement presented by Pochota fendleri seedlings in three substrates with addition of nutrient solution follows the descending order: macronutrients (N > Ca > K > Mg > P > S and micronutrients (Fe > Mn > B > Zn > Cu.

Yield Gap, Indigenous Nutrient Supply and Nutrient Use Efficiency for Maize in China

Science.gov (United States)

Xu, Xinpeng; Liu, Xiaoyan; He, Ping; Johnston, Adrian M.; Zhao, Shicheng; Qiu, Shaojun; Zhou, Wei

2015-01-01

Great achievements have been attained in agricultural production of China, while there are still many difficulties and challenges ahead that call for put more efforts to overcome to guarantee food security and protect environment simultaneously. Analyzing yield gap and nutrient use efficiency will help develop and inform agricultural policies and strategies to increase grain yield. On-farm datasets from 2001 to 2012 with 1,971 field experiments for maize (Zea mays L.) were collected in four maize agro-ecological regions of China, and the optimal management (OPT), farmers’ practice (FP), a series of nutrient omission treatments were used to analyze yield gap, nutrient use efficiency and indigenous nutrient supply by adopting meta-analysis and ANOVA analysis. Across all sites, the average yield gap between OPT and FP was 0.7 t ha-1, the yield response to nitrogen (N), phosphorus (P), and potassium (K) were 1.8, 1.0, and 1.2 t ha-1, respectively. The soil indigenous nutrient supply of N, P, and K averaged 139.9, 33.7, and 127.5 kg ha-1, respectively. As compared to FP, the average recovery efficiency (RE) of N, P, and K with OPT increased by percentage point of 12.2, 5.5, and 6.5, respectively. This study indicated that there would be considerable potential to further improve yield and nutrient use efficiency in China, and will help develop and inform agricultural policies and strategies, while some management measures such as soil, plant and nutrient are necessary and integrate with advanced knowledge and technologies. PMID:26484543

Yield Gap, Indigenous Nutrient Supply and Nutrient Use Efficiency for Maize in China.

Science.gov (United States)

Xu, Xinpeng; Liu, Xiaoyan; He, Ping; Johnston, Adrian M; Zhao, Shicheng; Qiu, Shaojun; Zhou, Wei

2015-01-01

Great achievements have been attained in agricultural production of China, while there are still many difficulties and challenges ahead that call for put more efforts to overcome to guarantee food security and protect environment simultaneously. Analyzing yield gap and nutrient use efficiency will help develop and inform agricultural policies and strategies to increase grain yield. On-farm datasets from 2001 to 2012 with 1,971 field experiments for maize (Zea mays L.) were collected in four maize agro-ecological regions of China, and the optimal management (OPT), farmers' practice (FP), a series of nutrient omission treatments were used to analyze yield gap, nutrient use efficiency and indigenous nutrient supply by adopting meta-analysis and ANOVA analysis. Across all sites, the average yield gap between OPT and FP was 0.7 t ha-1, the yield response to nitrogen (N), phosphorus (P), and potassium (K) were 1.8, 1.0, and 1.2 t ha-1, respectively. The soil indigenous nutrient supply of N, P, and K averaged 139.9, 33.7, and 127.5 kg ha-1, respectively. As compared to FP, the average recovery efficiency (RE) of N, P, and K with OPT increased by percentage point of 12.2, 5.5, and 6.5, respectively. This study indicated that there would be considerable potential to further improve yield and nutrient use efficiency in China, and will help develop and inform agricultural policies and strategies, while some management measures such as soil, plant and nutrient are necessary and integrate with advanced knowledge and technologies.

Data for a regional approach to the development of an effects-based nutrient criterion for wadable streams

Science.gov (United States)

Crawford, J. Kent; Loper, Connie A.; Beaman, Joseph R.; Soehl, Anna G.; Brown, Will S.

2007-01-01

than 5 percent for any constituent analyzed. For periphyton identifications, duplicate samples had Jaccard Coefficient of Community values slightly greater than 0.5. This indicates the periphyton sampling protocol used provided a sample that was only moderately reproducible. Jaccard Coefficients for three periphyton samples split between two independent labs were 0.2, 0.11, and 0.08. These very low values suggest a poor concurrence on species identifications performed by the two labs. As a result of these quality-control samples, the slides prepared for diatom identifications were sent to the Academy of Natural Sciences for re-identification. Caution is urged when interpreting periphyton-community information from this study. This report and the raw data from the study are available online at http://pubs.usgs.gov/ds257

DAF-2 and ERK Couple Nutrient Availability to Meiotic Progression during Caenorhabditis elegans Oogenesis

Science.gov (United States)

Lopez, Andrew L.; Chen, Jessica; Joo, Hyoe-Jin; Drake, Melanie; Shidate, Miri; Kseib, Cedric; Arur, Swathi

2013-01-01

Coupling the production of mature gametes and fertilized zygotes to favorable nutritional conditions improves reproductive success. In invertebrates, the proliferation of female germ line stem cells is regulated by nutritional status. But, in mammals the number of female germ line stem cells is set early in development, with oocytes progressing through meiosis later in life. Mechanisms that couple later steps of oogenesis to environmental conditions remain largely undefined. We show that in the presence of food, the DAF-2 insulin-like receptor signals through the RAS-ERK pathway to drive meiotic prophase I progression and oogenesis; in the absence of food, the resultant inactivation of insulin-like signaling leads to downregulation of RAS-ERK pathway, and oogenesis is stalled. Thus, the insulin-like signaling pathway couples nutrient sensing to meiotic I progression and oocyte production in C. elegans, ensuring that oocytes are only produced under conditions favorable for the survival of the resulting zygotes. PMID:24120884

Adult Nutrient Intakes from Current National Dietary Surveys of European Populations

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Holly L. Rippin

2017-11-01

Full Text Available The World Health Organization (WHO encourages countries to undertake national dietary survey (NDS but implementation and reporting is inconsistent. This paper provides an up-to-date review of adult macro and micronutrient intakes in European populations as reported by NDS. It uses WHO Recommended Nutrient Intakes (RNIs to assess intake adequacy and highlight areas of concern. NDS information was gathered primarily by internet searches and contacting survey authors and nutrition experts. Survey characteristics and adult intakes by gender/age group were extracted for selected nutrients and weighted means calculated by region. Of the 53 WHO Europe countries, over a third (n = 19, mainly Central & Eastern European countries (CEEC, had no identifiable NDS. Energy and nutrient intakes were extracted for 21 (40% countries but differences in age group, methodology, under-reporting and nutrient composition databases hindered inter-country comparisons. No country met more than 39% WHO RNIs in all age/gender groups; macronutrient RNI achievement was poorer than micronutrient. Overall RNI attainment was slightly worse in CEEC and lower in women and female elderly. Only 40% countries provided adult energy and nutrient intakes. The main gaps lie in CEEC, where unknown nutrient deficiencies may occur. WHO RNI attainment was universally poor for macronutrients, especially for women, the female elderly and CEEC. All countries could be encouraged to report a uniform nutrient set and sub-analyses of nationally representative nutrient intakes.

Biochar from sugarcane filtercake reduces soil CO2 emissions relative to raw residue and improves water retention and nutrient availability in a highly-weathered tropical soil.

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Angela Joy Eykelbosh

Full Text Available In Brazil, the degradation of nutrient-poor Ferralsols limits productivity and drives agricultural expansion into pristine areas. However, returning agricultural residues to the soil in a stabilized form may offer opportunities for maintaining or improving soil quality, even under conditions that typically promote carbon loss. We examined the use of biochar made from filtercake (a byproduct of sugarcane processing on the physicochemical properties of a cultivated tropical soil. Filtercake was pyrolyzed at 575°C for 3 h yielding a biochar with increased surface area and porosity compared to the raw filtercake. Filtercake biochar was primarily composed of aromatic carbon, with some residual cellulose and hemicellulose. In a three-week laboratory incubation, CO2 effluxes from a highly weathered Ferralsol soil amended with 5% biochar (dry weight, d.w. were roughly four-fold higher than the soil-only control, but 23-fold lower than CO2 effluxes from soil amended with 5% (d.w. raw filtercake. We also applied vinasse, a carbon-rich liquid waste from bioethanol production typically utilized as a fertilizer on sugarcane soils, to filtercake- and biochar-amended soils. Total CO2 efflux from the biochar-amended soil in response to vinasse application was only 5% of the efflux when vinasse was applied to soil amended with raw filtercake. Furthermore, mixtures of 5 or 10% biochar (d.w. in this highly weathered tropical soil significantly increased water retention within the plant-available range and also improved nutrient availability. Accordingly, application of sugarcane filtercake as biochar, with or without vinasse application, may better satisfy soil management objectives than filtercake applied to soils in its raw form, and may help to build soil carbon stocks in sugarcane-cultivating regions.

Herbivores and nutrients control grassland plant diversity via light limitation

Science.gov (United States)

Borer, Elizabeth T.; Seabloom, Eric W.; Gruner, Daniel S.; Harpole, W. Stanley; Hillebrand, Helmut; Lind, Eric M.; Alder, Peter B.; Alberti, Juan; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S.; Brudvig, Lars A.; Buckley, Yvonne M.; Cadotte, Marc; Chu, Cheng-Jin; Cleland, Elsa E.; Crawley, Michael J.; Daleo, Pedro; Damschen, Ellen Ingman; Davies, Kendi F.; DeCrappeo, Nicole M.; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W.; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A.; Knops, Johannes M.H.; La Pierre, Kimberly J.; Leakey, Andrew D.B.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Mortensen, Brent; O'Halloran, Lydia R.; Orrock, John L.; Pascual, Jesús; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Williams, Ryan J.; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

2014-01-01

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

A Nutrient-In-Water Resource for Sustainable Crop

African Journals Online (AJOL)

sys01

2011-09-03

Sep 3, 2011 ... calcium in the “Acid Sands” soils of south-eastern Nigeria. Two types of .... some forty-eight perforated plastic pots and laid out in the University Teaching ..... capable of stabilizing soil reactions, availability of essential nutrients ...

Nutrient imbalance in Norway spruce

International Nuclear Information System (INIS)

Thelin, Gunnar

2000-11-01

The studies presented in my thesis indicate that growing Norway spruce in monoculture does not constitute sustainable forest management in a high N and S deposition environment, such as in southern Sweden. The combination of N-induced high growth rates and leaching due to soil acidification causes soil reserves of nutrients to decrease. This will increase the risk of nutrient imbalance within the trees when nutrient demands are not met. The development of nutrient imbalance in Scania, southern Sweden, was shown as negative trends in needle and soil nutrient status from the mid-80s to the present in Norway spruce and Scots pine stands. This imbalance appears to be connected to high levels of N and S deposition. Clear negative effects on tree vitality were found when using a new branch development method. Today, growth and vitality seems to be limited by K, rather than N, in spruce stands older than 40 years. However, younger stands appear to be able to absorb the deposited N without negative effects on growth and vitality. When investigating effects of nutrient stress on tree vitality, indicators such as branch length and shoot multiplication rate, which include effects accumulated over several years, are suitable. Countermeasures are needed in order to maintain the forest production at a high level. Positive effects on tree nutrient status after vitality fertilization (N-free fertilization) was shown in two micronutrient deficient stands in south-central Sweden. In addition, tree vitality was positively affected after the application of a site-adapted fertilizer to the canopy. Site-adaption of fertilizers will most likely improve the possibilities of a positive response on tree growth and vitality in declining stands. In a survey of Norway spruce in mixtures with beech, birch, or oak compared to monocultures it was shown that spruce nutrient status was higher in mixtures with deciduous species than in monocultures. By using mixed-species stands the need for

Nutrient imbalance in Norway spruce

Energy Technology Data Exchange (ETDEWEB)

Thelin, Gunnar

2000-11-01

The studies presented in my thesis indicate that growing Norway spruce in monoculture does not constitute sustainable forest management in a high N and S deposition environment, such as in southern Sweden. The combination of N-induced high growth rates and leaching due to soil acidification causes soil reserves of nutrients to decrease. This will increase the risk of nutrient imbalance within the trees when nutrient demands are not met. The development of nutrient imbalance in Scania, southern Sweden, was shown as negative trends in needle and soil nutrient status from the mid-80s to the present in Norway spruce and Scots pine stands. This imbalance appears to be connected to high levels of N and S deposition. Clear negative effects on tree vitality were found when using a new branch development method. Today, growth and vitality seems to be limited by K, rather than N, in spruce stands older than 40 years. However, younger stands appear to be able to absorb the deposited N without negative effects on growth and vitality. When investigating effects of nutrient stress on tree vitality, indicators such as branch length and shoot multiplication rate, which include effects accumulated over several years, are suitable. Countermeasures are needed in order to maintain the forest production at a high level. Positive effects on tree nutrient status after vitality fertilization (N-free fertilization) was shown in two micronutrient deficient stands in south-central Sweden. In addition, tree vitality was positively affected after the application of a site-adapted fertilizer to the canopy. Site-adaption of fertilizers will most likely improve the possibilities of a positive response on tree growth and vitality in declining stands. In a survey of Norway spruce in mixtures with beech, birch, or oak compared to monocultures it was shown that spruce nutrient status was higher in mixtures with deciduous species than in monocultures. By using mixed-species stands the need for

Complementarity in nutrient foraging strategies of absorptive fine roots and arbuscular mycorrhizal fungi across 14 coexisting subtropical tree species.

Science.gov (United States)

Liu, Bitao; Li, Hongbo; Zhu, Biao; Koide, Roger T; Eissenstat, David M; Guo, Dali

2015-10-01

In most cases, both roots and mycorrhizal fungi are needed for plant nutrient foraging. Frequently, the colonization of roots by arbuscular mycorrhizal (AM) fungi seems to be greater in species with thick and sparsely branched roots than in species with thin and densely branched roots. Yet, whether a complementarity exists between roots and mycorrhizal fungi across these two types of root system remains unclear. We measured traits related to nutrient foraging (root morphology, architecture and proliferation, AM colonization and extramatrical hyphal length) across 14 coexisting AM subtropical tree species following root pruning and nutrient addition treatments. After root pruning, species with thinner roots showed more root growth, but lower mycorrhizal colonization, than species with thicker roots. Under multi-nutrient (NPK) addition, root growth increased, but mycorrhizal colonization decreased significantly, whereas no significant changes were found under nitrogen or phosphate additions. Moreover, root length proliferation was mainly achieved by altering root architecture, but not root morphology. Thin-root species seem to forage nutrients mainly via roots, whereas thick-root species rely more on mycorrhizal fungi. In addition, the reliance on mycorrhizal fungi was reduced by nutrient additions across all species. These findings highlight complementary strategies for nutrient foraging across coexisting species with contrasting root traits. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Spatially explicit modeling of particulate nutrient flux in Large global rivers

Science.gov (United States)

Cohen, S.; Kettner, A.; Mayorga, E.; Harrison, J. A.

2017-12-01

Water, sediment, nutrient and carbon fluxes along river networks have undergone considerable alterations in response to anthropogenic and climatic changes, with significant consequences to infrastructure, agriculture, water security, ecology and geomorphology worldwide. However, in a global setting, these changes in fluvial fluxes and their spatial and temporal characteristics are poorly constrained, due to the limited availability of continuous and long-term observations. We present results from a new global-scale particulate modeling framework (WBMsedNEWS) that combines the Global NEWS watershed nutrient export model with the spatially distributed WBMsed water and sediment model. We compare the model predictions against multiple observational datasets. The results indicate that the model is able to accurately predict particulate nutrient (Nitrogen, Phosphorus and Organic Carbon) fluxes on an annual time scale. Analysis of intra-basin nutrient dynamics and fluxes to global oceans is presented.

Nutrient and carbohydrate partitioning in sorghum stover

International Nuclear Information System (INIS)

Powell, J.M.; Hons, F.M.; McBee, G.G.

1991-01-01

Sorghum [Sorghum bicolor (L.) Moench] stover has been demonstrated to be a potential biomass energy source. Complete aboveground crop removal, however, can result in soil degradation. Differential dry matter, nutrient, and carbohydrate partitioning by sorghum cultivars may allow management strategies that return certain parts to the field while removing other portions for alternative uses, such as energy production. A field study was conducted to determine N,P,K, nonstructural carbohydrate, cellulose hemicellulose, and lignin distributions in stover of three diverse sorghum cultivars of differing harvest indices. Determinations were based on total vegetative biomass; total blades; total stalks; and upper middle, and lower blades and stalks. Concentrations of N and P were higher in blades than stalks and generally declines from upper to lower stover parts. Large carbohydrate and lignin concentration differences were observed on the basis of cultivar and stover part. Greater nutrient partitioning to the upper third of the intermediate and forage-type sorghum stovers was observed as compared to the conventional grain cultivar. Stover carbohydrates for all cultivars were mainly contained in the lower two-thirds of the stalk fraction. A system was proposed for returning upper stover portion to soil, while removing remaining portions for alternative uses

USA Nutrient managment forecasting via the "Fertilizer Forecaster": linking surface runnof, nutrient application and ecohydrology.

Science.gov (United States)

Drohan, Patrick; Buda, Anthony; Kleinman, Peter; Miller, Douglas; Lin, Henry; Beegle, Douglas; Knight, Paul

2017-04-01

USA and state nutrient management planning offers strategic guidance that strives to educate farmers and those involved in nutrient management to make wise management decisions. A goal of such programs is to manage hotspots of water quality degradation that threaten human and ecosystem health, water and food security. The guidance provided by nutrient management plans does not provide the day-to-day support necessary to make operational decisions, particularly when and where to apply nutrients over the short term. These short-term decisions on when and where to apply nutrients often make the difference between whether the nutrients impact water quality or are efficiently utilized by crops. Infiltrating rainfall events occurring shortly after broadcast nutrient applications are beneficial, given they will wash soluble nutrients into the soil where they are used by crops. Rainfall events that generate runoff shortly after nutrients are broadcast may wash off applied nutrients, and produce substantial nutrient losses from that site. We are developing a model and data based support tool for nutrient management, the Fertilizer Forecaster, which identifies the relative probability of runoff or infiltrating events in Pennsylvania (PA) landscapes in order to improve water quality. This tool will support field specific decisions by farmers and land managers on when and where to apply fertilizers and manures over 24, 48 and 72 hour periods. Our objectives are to: (1) monitor agricultural hillslopes in watersheds representing four of the five Physiographic Provinces of the Chesapeake Bay basin; (2) validate a high resolution mapping model that identifies soils prone to runoff; (3) develop an empirically based approach to relate state-of-the-art weather forecast variables to site-specific rainfall infiltration or runoff occurrence; (4) test the empirical forecasting model against alternative approaches to forecasting runoff occurrence; and (5) recruit farmers from the four

A study on the mineral elements available in aquaponics, their impact on lettuce productivity and the potential improvement of their availability.

OpenAIRE

Delaide, Boris

2017-01-01

Aquaponics is an integrated farming concept that combines fish and hydroponic plant production in a recirculating water system. This innovative technique has the potential to reduce the impact of fish and plant production on the environment by namely closing the nutrient loop. Indeed, the nutrients leaving the fish part are used to grow hydroponic plants. This thesis focused on the mineral elements available in aquaponics to grow plants. The thesis started by deepening the aquaponic conce...

Nutrient production from dairy cattle manure and loading on arable land

Directory of Open Access Journals (Sweden)

Seunggun Won

2017-01-01

Full Text Available Objective Along with increasing livestock products via intensive rearing, the accumulation of livestock manure has become a serious issue due to the fact that there is finite land for livestock manure recycling via composting. The nutrients from livestock manure accumulate on agricultural land and the excess disembogues into streams causing eutrophication. In order to systematically manage nutrient loading on agricultural land, quantifying the amount of nutrients according to their respective sources is very important. However, there is a lack of research concerning nutrient loss from livestock manure during composting or storage on farms. Therefore, in the present study we quantified the nutrients from dairy cattle manure that were imparted onto agricultural land. Methods Through investigation of 41 dairy farms, weight reduction and volatile solids (VS, total nitrogen (TN, and total phosphorus (TP changes of dairy cattle manure during the storage and composting periods were analyzed. In order to support the direct investigation and survey on site, the three cases of weight reduction during the storing and composting periods were developed according to i experiment, ii reference, and iii theoretical changes in phosphorus content (ΔP = 0. Results The data revealed the nutrient loading coefficients (NLCs of VS, TN, and TP on agricultural land were 1.48, 0.60, and 0.66, respectively. These values indicated that the loss of nitrogen and phosphorus was 40% and 34%, respectively, and that there was an increase of VS since bedding materials were mixed with excretion in the barn. Conclusion As result of nutrient-footprint analyses, the amounts of TN and TP particularly entered on arable land have been overestimated if applying the nutrient amount in fresh manure. The NLCs obtained in this study may assist in the development of a database to assess the accurate level of manure nutrient loading on soil and facilitate systematic nutrient management.

Nutrient and antinutrient composition of yellow yam (Dioscorea cayenensis products

Directory of Open Access Journals (Sweden)

Oladejo Thomas Adepoju

2017-04-01

Full Text Available The data presented in this article are related to research article titled “Effects of processing methods on nutrient and antinutrient composition of yellow yam (Dioscorea cayenensis products” (Adepoju et al., 2016 [1]. This article documented information on nutrient and antinutrient composition as well as nutrient retention of Dioscorea cayenensis products. Fresh Dioscorea cayenensis tubers obtained from Bodija market were prepared into raw sample and local delicacies and analysed for proximate, mineral, vitamin and antinutrient composition using AOAC methods [2]. Data obtained were analysed using ANOVA, and level of significance set at p<0.05. Processing significantly improved macronutrients and energy content of yam products, and led to significant reduction in values of all antinutrient content of the products (p<0.05.

Incorporating hydrologic variability into nutrient spiraling

Science.gov (United States)

Doyle, Martin W.

2005-09-01

Nutrient spiraling describes the path of a nutrient molecule within a stream ecosystem, combining the biochemical cycling processes with the downstream driving force of stream discharge. To date, nutrient spiraling approaches have been hampered by their inability to deal with fluctuating flows, as most studies have characterized nutrient retention within only a small range of discharges near base flow. Here hydrologic variability is incorporated into nutrient spiraling theory by drawing on the fluvial geomorphic concept of effective discharge. The effective discharge for nutrient retention is proposed to be that discharge which, over long periods of time, is responsible for the greatest portion of nutrient retention. A developed analytical model predicts that the effective discharge for nutrient retention will equal the modal discharge for small streams or those with little discharge variability. As modal discharge increases or discharge variability increases, the effective discharge becomes increasingly less than the modal discharge. In addition to the effective discharge, a new metric is proposed, the functionally equivalent discharge, which is the single discharge that will reproduce the magnitude of nutrient retention generated by the full hydrologic frequency distribution when all discharge takes place at that rate. The functionally equivalent discharge was found to be the same as the modal discharge at low hydrologic variability, but increasingly different from the modal discharge at large hydrologic variability. The functionally equivalent discharge provides a simple quantitative means of incorporating hydrologic variability into long-term nutrient budgets.

Investment in secreted enzymes during nutrient-limited growth is utility dependent.

Science.gov (United States)

Cezairliyan, Brent; Ausubel, Frederick M

2017-09-12

Pathogenic bacteria secrete toxins and degradative enzymes that facilitate their growth by liberating nutrients from the environment. To understand bacterial growth under nutrient-limited conditions, we studied resource allocation between cellular and secreted components by the pathogenic bacterium Pseudomonas aeruginosa during growth on a protein substrate that requires extracellular digestion by secreted proteases. We identified a quantitative relationship between the rate of increase of cellular biomass under nutrient-limiting growth conditions and the rate of increase in investment in secreted proteases. Production of secreted proteases is stimulated by secreted signals that convey information about the utility of secreted proteins during nutrient-limited growth. Growth modeling using this relationship recapitulated the observed kinetics of bacterial growth on a protein substrate. The proposed regulatory strategy suggests a rationale for quorum-sensing-dependent stimulation of the production of secreted enzymes whereby investment in secreted enzymes occurs in proportion to the utility they confer. Our model provides a framework that can be applied toward understanding bacterial growth in many environments where growth rate is limited by the availability of nutrients.

Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics

Science.gov (United States)

Marcarelli, Amy M.; Baxter, Colden V.; Wipfli, Mark S.

2014-01-01

Mitigation activities designed to supplement nutrient and organic matter inputs to streams experiencing decline or loss of Pacific salmon typically presuppose that an important pathway by which salmon nutrients are moved to fish (anadromous and/or resident) is via nutrient incorporation by biofilms and subsequent bottom-up stimulation of biofilm production, which is nutrient-limited in many ecosystems where salmon returns have declined. Our objective was to quantify the magnitude of nutrient incorporation and biofilm dynamics that underpin this indirect pathway in response to experimental additions of salmon carcasses and pelletized fish meal (a.k.a., salmon carcass analogs) to 500-m reaches of central Idaho streams over three years. Biofilm standing crops increased 2–8-fold and incorporated marine-derived nutrients (measured using 15N and 13C) in the month following treatment, but these responses did not persist year-to-year. Biofilms were nitrogen (N) limited before treatments, and remained N limited in analog, but not carcass-treated reaches. Despite these biofilm responses, in the month following treatment total N load was equal to 33–47% of the N added to the treated reaches, and N spiraling measurements suggested that as much as 20%, but more likely 2–3% of added N was taken up by microbes. Design of biologically and cost-effective strategies for nutrient addition will require understanding the rates at which stream microbes take up nutrients and the downstream distance traveled by exported nutrients.

Effects of nutrient omission in Caesalpinia echinata plants

Directory of Open Access Journals (Sweden)

Sergio Valiengo Valeri

2014-03-01

Full Text Available The objective of this study was to evaluate the growth, the morphological alterations and the mineral composition of brazilwood (Caesalpinia echinata plants caused by mineral nutrients omission in a green house experiment. The experimental units were distributed in the green house according to a completely random design. The treatments, each repeated five times, were the following : check (natural soil, complete (N, P, K, Ca, Mg, S, B, Cu, Mn, and Zn and a complete solution but for the omission of one of the nutrients in parenthesis. Each plot was represented by a plant growing in a 7 dm3 vase filled with Quartzarenic Neosol. The analyzed variables were the following: visual nutritional deficiency symptoms, plant height, stem diameter, shoot dry matter, stem, branches and leaves included, and leaf nutrients level. The omission of nitrogen limited plant growth in height and shoot biomass production. The first visual deficiency symptoms were those due to N omission followed by those caused by P, Ca, Mg, S, Cu, and Mn omissions. Later on the K and B deficiency symptoms became visible. The omission of a nutrient always caused its level in the leaves to be significantly lower than that found when it was not omitted.

A statistical method to base nutrient recommendations on meta-analysis of intake and health-related status biomarkers.

Directory of Open Access Journals (Sweden)

Hilko van der Voet

Full Text Available Nutrient recommendations in use today are often derived from relatively old data of few studies with few individuals. However, for many nutrients, including vitamin B-12, extensive data have now become available from both observational studies and randomized controlled trials, addressing the relation between intake and health-related status biomarkers. The purpose of this article is to provide new methodology for dietary planning based on dose-response data and meta-analysis. The methodology builds on existing work, and is consistent with current methodology and measurement error models for dietary assessment. The detailed purposes of this paper are twofold. Firstly, to define a Population Nutrient Level (PNL for dietary planning in groups. Secondly, to show how data from different sources can be combined in an extended meta-analysis of intake-status datasets for estimating PNL as well as other nutrient intake values, such as the Average Nutrient Requirement (ANR and the Individual Nutrient Level (INL. For this, a computational method is presented for comparing a bivariate lognormal distribution to a health criterion value. Procedures to meta-analyse available data in different ways are described. Example calculations on vitamin B-12 requirements were made for four models, assuming different ways of estimating the dose-response relation, and different values of the health criterion. Resulting estimates of ANRs and less so for INLs were found to be sensitive to model assumptions, whereas estimates of PNLs were much less sensitive to these assumptions as they were closer to the average nutrient intake in the available data.

Nutrient timing revisited: is there a post-exercise anabolic window?

Directory of Open Access Journals (Sweden)

Aragon Alan Albert

2013-01-01

Full Text Available Abstract Nutrient timing is a popular nutritional strategy that involves the consumption of combinations of nutrients--primarily protein and carbohydrate--in and around an exercise session. Some have claimed that this approach can produce dramatic improvements in body composition. It has even been postulated that the timing of nutritional consumption may be more important than the absolute daily intake of nutrients. The post-exercise period is widely considered the most critical part of nutrient timing. Theoretically, consuming the proper ratio of nutrients during this time not only initiates the rebuilding of damaged muscle tissue and restoration of energy reserves, but it does so in a supercompensated fashion that enhances both body composition and exercise performance. Several researchers have made reference to an anabolic “window of opportunity” whereby a limited time exists after training to optimize training-related muscular adaptations. However, the importance - and even the existence - of a post-exercise ‘window’ can vary according to a number of factors. Not only is nutrient timing research open to question in terms of applicability, but recent evidence has directly challenged the classical view of the relevance of post-exercise nutritional intake with respect to anabolism. Therefore, the purpose of this paper will be twofold: 1 to review the existing literature on the effects of nutrient timing with respect to post-exercise muscular adaptations, and; 2 to draw relevant conclusions that allow practical, evidence-based nutritional recommendations to be made for maximizing the anabolic response to exercise.

Nutrientes no mantilho em pastagem nativa sob distintos manejos

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Heringer Ingrid

2002-01-01

Full Text Available A avaliação da quantidade de nutrientes no mantilho é importante para verificar a ciclagem de nutrientes e a preservação da fertilidade do solo. O teor e a quantidade de nutrientes no mantilho e material senescente foram estudados em pastagem nativa sob pastejo, sujeita à queima e manejos alternativos, durante um ano, nos Campos de Cima da Serra, no Rio Grande do Sul. O acúmulo de mantilho foi coletado em gaiolas de exclusão ao pastejo, a cada 90 dias. O mantilho representou o material morto desprendido da planta existente junto à superfície do solo. A esta fração foi adicionado o material senescente ligado à planta. Os tratamentos foram pastagem nativa sob pastejo sem queima e sem roçada há 32 anos, melhorada há sete anos e com queima bienal há mais de 100 anos. O delineamento experimental foi completamente casualizado com três repetições. Os teores de Ca e Mg no mantilho mais material senescente foram inferiores no tratamento queimado em relação às áreas sem queima. O melhoramento da pastagem aumentou os teores de nutrientes nos tecidos. A quantidade acumulada de nutrientes, reflexo da produção de mantilho e material senescente, foi maior nos sistemas sem queima.

Production of Short-Rotation Woody Crops Grown with a Range of Nutrient and Water Availability: Establishment Report and First-Year Responses

Energy Technology Data Exchange (ETDEWEB)

D.R. Coyle; J. Blake; K. Britton; M.; R.G. Campbell; J. Cox; B. Cregg; D. Daniels; M. Jacobson; K. Johnsen; T. McDonald; K. McLeod; E.; D. Robison; R. Rummer; F. Sanchez; J.; B. Stokes; C. Trettin; J. Tuskan; L. Wright; S. Wullschleger

2003-12-31

Coleman, M.D., et. al. 2003. Production of Short-Rotation Woody Crops Grown with a Range of Nutrient and Water Availability: Establishment Report and First-Year Responses. Report. USDA Forest Service, Savannah River, Aiken, SC. 26 pp. Abstract: Many researchers have studied the productivity potential of intensively managed forest plantations. However, we need to learn more about the effects of fundamental growth processes on forest productivity; especially the influence of aboveground and belowground resource acquisition and allocation. This report presents installation, establishment, and first-year results of four tree species (two cottonwood clones, sycamore, sweetgum, and loblolly pine) grown with fertilizer and irrigation treatments. At this early stage of development, irrigation and fertilization were additive only in cottonwood clone ST66 and sweetgum. Leaf area development was directly related to stem growth, but root production was not always consistent with shoot responses, suggesting that allocation of resources varies among treatments. We will evaluate the consequences of these early responses on resource availability in subsequent growing seasons. This information will be used to: (1) optimize fiber and bioenergy production; (2) understand carbon sequestration; and (3) develop innovative applications such as phytoremediation; municipal, industrial, and agricultural wastes management; and protection of soil, air, and water resources.

Nutrient Controls on Methane Emissions in a Permafrost Thaw Subarctic Peatland

Science.gov (United States)

Kashi, N. N.; Perryman, C. R.; Malhotra, A.; Marek, E. A.; Giesler, R.; Varner, R. K.

2015-12-01

Permafrost peatlands in northern latitudes are large reservoirs of sequestered carbon that are vulnerable to climate change. While peatlands account for a small fraction of total global land surfaces, their potential to release sequestered carbon in response to higher temperatures is of concern. Of particular relevance is the conversion of these carbon stores into methane (CH4), a strong greenhouse gas with a global warming potential 20 times greater than that of CO2 over a 100-year time frame. Here, we explore how key nutrients impact the consumption of CH4 at the Stordalen Mire in Abisko, Sweden, a discontinuous permafrost peatland with expanding thaw over the last century. Peatland CH4 emissions are highly spatially variable due to multiple emission pathways and strong dependence on several environmental factors. Among controls on CH4 emissions, such as temperature and water table depth, primary production of wetland vegetation is also a strong factor in the variability of CH4 emissions. Plant community shifts among permafrost thaw stages subsequently change nutrient cycling and availability, which in turn impacts primary production. Early stages of permafrost thaw are mosaicked with a variety of vascular plants and mosses. We analyzed potential enzymatic activities of chitinase, glucosidase, and phosphatase as proxies for organic nitrogen, carbon, and phosphorus cycling, respectively, in tandem with potential CH4 oxidation rates. In addition, stoichiometric ratios of carbon, nitrogen, and phosphorus concentrations are used to illustrate nutrient limitation controls on CH4 oxidation rates. While CH4 emissions are low throughout initial thaw stages, highest rates of potential CH4 oxidation. These permafrost thaw-induced CH4 oxidation rates are 5 and 11 times higher, in the surface and depth of the peat profile respectively, than subsequent aerobic permafrost thaw stages. As CH4 emissions are low in intact permafrost peatlands, these high rates of potential CH4

Absorción de nutrientes a través de la hoja

Directory of Open Access Journals (Sweden)

Ritma Giordana Murillo Castillo

2013-03-01

Full Text Available La fertilización foliar es una práctica efectiva para la corrección de deficiencias nutricionales en plantas que se encuentran bajo condiciones de estrés o en suelos con baja disponibilidad de nutrientes. Consiste en aplicar disoluciones de nutrientes directamente sobre las hojas. Esta absorción en la hoja se desarrolla mayoritariamente a través de la epidermis, por difusión, debido al gradiente de concentración del nutriente que se establece entre la superficie de la hoja y en el interior de la epidermis. Una vez que el nutriente ha ingresado al citoplasma de las células epidermales, la movilización de este ocurre en forma relativamente expedita. La principal barrera que el nutriente debe atravesar es la cutícula, la cual está compuesta de ceras. Las características físico-químicas del nutriente, tales como tamaño y polaridad controlan la tasa de absorción. El presente artículo provee una descripción detallada del proceso de absorción foliar de nutrientes y su influencia en el desarrollo y uso de fertilizantes foliares.

Short-Term Effects of Drying-Rewetting and Long-Term Effects of Nutrient Loading on Periphyton N:P Stoichiometry

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Andres D. Sola

2018-01-01

Full Text Available Nitrogen (N and phosphorus (P concentrations and N:P ratios critically influence periphyton productivity and nutrient cycling in aquatic ecosystems. In coastal wetlands, variations in hydrology and water source (fresh or marine influence nutrient availability, but short-term effects of drying and rewetting and long-term effects of nutrient exposure on periphyton nutrient retention are uncertain. An outdoor microcosm experiment simulated short-term exposure to variation in drying-rewetting frequency on periphyton mat nutrient retention. A 13-year dataset from freshwater marshes of the Florida Everglades was examined for the effect of long-term proximity to different N and P sources on mat-forming periphyton nutrient standing stocks and stoichiometry. Field sites were selected from one drainage with shorter hydroperiod and higher connectivity to freshwater anthropogenic nutrient supplies (Taylor Slough/Panhandle, TS/Ph and another drainage with longer hydroperiod and higher connectivity to marine nutrient supplies (Shark River Slough, SRS. Total P, but not total N, increased in periphyton mats exposed to both low and high drying-rewetting frequency with respect to the control mats in our experimental microcosm. In SRS, N:P ratios slightly decreased downstream due to marine nutrient supplies, while TS/Ph increased. Mats exposed to short-term drying-rewetting had higher nutrient retention, similar to nutrient standing stocks from long-term field data. Periphyton mat microbial communities may undergo community shifts upon drying-rewetting and chronic exposure to nutrient loads. Additional work on microbial species composition may further explain how periphyton communities interact with drying-rewetting dynamics to influence nutrient cycling and retention in wetlands.

Response diversity of free-floating plants to nutrient stoichiometry and temperature: growth and resting body formation

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Michael J. McCann

2016-03-01

Full Text Available Free-floating plants, like most groups of aquatic primary producers, can become nuisance vegetation under certain conditions. On the other hand, there is substantial optimism for the applied uses of free-floating plants, such as wastewater treatment, biofuel production, and aquaculture. Therefore, understanding the species-specific responses of floating plants to abiotic conditions will inform both management decisions and the beneficial applications of these plants. I measured the responses of three floating plant species common in the northeast United States (Lemna minor, Spirodela polyrhiza, and Wolffia brasiliensis to nutrient stoichiometry (nitrogen and phosphorus and temperature in the laboratory. I also used survey data to determine the pattern of species richness of floating plants in the field and its relationship with the dominance of this group. Floating plant species exhibited unique responses to nutrient stoichiometry and temperature in the laboratory, especially under low temperatures (18 °C and low nutrient conditions (0.5 mg N L−1, 0.083 mg P L−1. The three species displayed an apparent tradeoff with different strategies of growth or dormancy. In the field, water bodies with three or more species of floating plants were not more frequently dominated by this group. The response diversity observed in the lab may not be associated with the dominance of this group in the field because it is masked by environmental variability, has a weak effect, or is only important during transient circumstances. Future research to develop applied uses of floating plants should examine response diversity across a greater range of species or clones and environmental conditions.

Deposition and conversion in soil of acids, acid-forming substances and nutrients

International Nuclear Information System (INIS)

Mayer, R.

1990-01-01

Balancing of material depositions entries is the basis for their evaluation. The acid depositions must be put in relation to the acid neutralization capacity and to the buffer rate of the soil. Every 'excess' in depositons leads to an acid supply into the sub-soil and/or into the groundwater system. On the one hand, the nutrient depositions are interpreted in relation to the nutrient supplies of the soil and their availability to the plants; and on the other hand with a view to the nutrient depletion through the polants. Excesses can also lead to a (non-desirable) pollution of aquatic systems, or else to an enhanced nutrient supply in the soil. Balancing is therefore a necessary aid for the evaluation of material depositions from the atmosphere. (orig./EF) [de

Increased sporulation of vesicular-arbuscular mycorrhizal fungi by manipulation of nutrient regimens.

Science.gov (United States)

Douds, D D; Schenck, N C

1990-02-01

Adjustment of pot culture nutrient solutions increased root colonization and sporulation of vesicular-arbuscular mycorrhizal (VAM) fungi. Paspalum notatum Flugge and VAM fungi were grown in a sandy soil low in N and available P. Hoagland nutrient solution without P enhanced sporulation in soil and root colonization of Acaulospora longula, Scutellospora heterogama, Gigaspora margarita, and a wide range of other VAM fungi over levels produced by a tap water control or nutrient solutions containing P. However, Glomus intraradices produced significantly more spores in plant roots in the tap water control treatment. The effect of the nutrient solutions was not due solely to N nutrition, because the addition of NH(4)NO(3) decreased both colonization and sporulation by G. margarita relative to levels produced by Hoagland solution without P.

A framework to assess biogeochemical response to ecosystem disturbance using nutrient partitioning ratios

Science.gov (United States)

Kranabetter, J. Marty; McLauchlan, Kendra K.; Enders, Sara K.; Fraterrigo, Jennifer M.; Higuera, Philip E.; Morris, Jesse L.; Rastetter, Edward B.; Barnes, Rebecca; Buma, Brian; Gavin, Daniel G.; Gerhart, Laci M.; Gillson, Lindsey; Hietz, Peter; Mack, Michelle C.; McNeil, Brenden; Perakis, Steven

2016-01-01

Disturbances affect almost all terrestrial ecosystems, but it has been difficult to identify general principles regarding these influences. To improve our understanding of the long-term consequences of disturbance on terrestrial ecosystems, we present a conceptual framework that analyzes disturbances by their biogeochemical impacts. We posit that the ratio of soil and plant nutrient stocks in mature ecosystems represents a characteristic site property. Focusing on nitrogen (N), we hypothesize that this partitioning ratio (soil N: plant N) will undergo a predictable trajectory after disturbance. We investigate the nature of this partitioning ratio with three approaches: (1) nutrient stock data from forested ecosystems in North America, (2) a process-based ecosystem model, and (3) conceptual shifts in site nutrient availability with altered disturbance frequency. Partitioning ratios could be applied to a variety of ecosystems and successional states, allowing for improved temporal scaling of disturbance events. The generally short-term empirical evidence for recovery trajectories of nutrient stocks and partitioning ratios suggests two areas for future research. First, we need to recognize and quantify how disturbance effects can be accreting or depleting, depending on whether their net effect is to increase or decrease ecosystem nutrient stocks. Second, we need to test how altered disturbance frequencies from the present state may be constructive or destructive in their effects on biogeochemical cycling and nutrient availability. Long-term studies, with repeated sampling of soils and vegetation, will be essential in further developing this framework of biogeochemical response to disturbance.

Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees.

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Chen, Weile; Koide, Roger T; Adams, Thomas S; DeForest, Jared L; Cheng, Lei; Eissenstat, David M

2016-08-02

Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich "hotspots" can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together.

Experimentally increased nutrient availability at the permafrost thaw front selectively enhances biomass production of deep-rooting subarctic peatland species.

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Keuper, Frida; Dorrepaal, Ellen; van Bodegom, Peter M; van Logtestijn, Richard; Venhuizen, Gemma; van Hal, Jurgen; Aerts, Rien

2017-10-01

Climate warming increases nitrogen (N) mineralization in superficial soil layers (the dominant rooting zone) of subarctic peatlands. Thawing and subsequent mineralization of permafrost increases plant-available N around the thaw-front. Because plant production in these peatlands is N-limited, such changes may substantially affect net primary production and species composition. We aimed to identify the potential impact of increased N-availability due to permafrost thawing on subarctic peatland plant production and species performance, relative to the impact of increased N-availability in superficial organic layers. Therefore, we investigated whether plant roots are present at the thaw-front (45 cm depth) and whether N-uptake ( 15 N-tracer) at the thaw-front occurs during maximum thaw-depth, coinciding with the end of the growing season. Moreover, we performed a unique 3-year belowground fertilization experiment with fully factorial combinations of deep- (thaw-front) and shallow-fertilization (10 cm depth) and controls. We found that certain species are present with roots at the thaw-front (Rubus chamaemorus) and have the capacity (R. chamaemorus, Eriophorum vaginatum) for N-uptake from the thaw-front between autumn and spring when aboveground tissue is largely senescent. In response to 3-year shallow-belowground fertilization (S) both shallow- (Empetrum hermaphroditum) and deep-rooting species increased aboveground biomass and N-content, but only deep-rooting species responded positively to enhanced nutrient supply at the thaw-front (D). Moreover, the effects of shallow-fertilization and thaw-front fertilization on aboveground biomass production of the deep-rooting species were similar in magnitude (S: 71%; D: 111% increase compared to control) and additive (S + D: 181% increase). Our results show that plant-available N released from thawing permafrost can form a thus far overlooked additional N-source for deep-rooting subarctic plant species and increase their

Global pressures, specific responses: effects of nutrient enrichment in streams from different biomes

International Nuclear Information System (INIS)

Artigas, Joan; García-Berthou, Emili; Gómez, Nora; Romaní, Anna M; Sabater, Sergi; Bauer, Delia E; Cochero, Joaquín; Cortelezzi, Agustina; Rodrigues-Capítulo, Alberto; Castro, Maria I; Donato, John C; Colautti, Darío C; Elosegi, Arturo; Feijoó, Claudia; Giorgi, Adonis; Leggieri, Leonardo; Muñoz, Isabel

2013-01-01

We assessed the effects of nutrient enrichment on three stream ecosystems running through distinct biomes (Mediterranean, Pampean and Andean). We increased the concentrations of N and P in the stream water 1.6–4-fold following a before–after control–impact paired series (BACIPS) design in each stream, and evaluated changes in the biomass of bacteria, primary producers, invertebrates and fish in the enriched (E) versus control (C) reaches after nutrient addition through a predictive-BACIPS approach. The treatment produced variable biomass responses (2–77% of explained variance) among biological communities and streams. The greatest biomass response was observed for algae in the Andean stream (77% of the variance), although fish also showed important biomass responses (about 9–48%). The strongest biomass response to enrichment (77% in all biological compartments) was found in the Andean stream. The magnitude and seasonality of biomass responses to enrichment were highly site specific, often depending on the basal nutrient concentration and on windows of ecological opportunity (periods when environmental constraints other than nutrients do not limit biomass growth). The Pampean stream, with high basal nutrient concentrations, showed a weak response to enrichment (except for invertebrates), whereas the greater responses of Andean stream communities were presumably favored by wider windows of ecological opportunity in comparison to those from the Mediterranean stream. Despite variation among sites, enrichment globally stimulated the algal-based food webs (algae and invertebrate grazers) but not the detritus-based food webs (bacteria and invertebrate shredders). This study shows that nutrient enrichment tends to globally enhance the biomass of stream biological assemblages, but that its magnitude and extent within the food web are complex and are strongly determined by environmental factors and ecosystem structure. (letter)

Maize nutrient uptake affected by genotype and fertilization

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Đalović Ivica

2015-01-01

Full Text Available The content of nutrients in maize are commonly related with fertilization and soil quality and rarely explained with the individual hybrid properties. Therefore, the aim of this study is to access a long term fertilization system on ear leaf of Mg, Fe, Mn and Cu content in six maize hybrids(NS 3014, NS 4015, NS 5043, NS 6010, NS 6030 and NS 7020. Samples were collected from a long-term experiment at the Rimski Šančevi experimental field of the Institute of Field and Vegetable Crops in Novi Sad. The study included maize monoculture and 2-year rotations with the application of NPK and manure. Results showed that ear Mg content was influenced with the treatments, hybrid and their interaction and ranged from 1.77-2.69 g kg-1. Iron variability was significantly affected with the treatments and interaction (hybrid x treatments in range from 103.2 to151.9g kg-1. The ear manganese content (41.1-63.6g kg-1 derived from treatments and hybrid effect and Cu (12.3-23.6 g kg-1 was significantly influenced with treatments. Across all treatments, in average, NS6030 had higher values of nutrient and NS3014 was lower in ear nutrient content. This indicates that vegetation length could favor nutrient accumulation. Obtained results suggested that even on fairly productive soil such as Chernozem hybrid selection and the balanced fertilization is crucial for managing the maize nutrient content. [Projekat Ministarsva nauke Republike Srbije, br. TR031073

Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions

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Gebremikael, Mesfin T.; Steel, Hanne; Buchan, David; Bert, Wim; de Neve, Stefaan

2016-09-01

The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota.

Balanço de carbono e nutrientes em plantio puro e misto de espécies florestais nativas no sudeste da Bahia Carbon and nutrient balance in pure and mixed stands of native tree species in Southeastern Bahia, Brazil

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Antonio Carlos da Gama-Rodrigues

2008-06-01

Full Text Available A manutenção da produção florestal depende da quantidade e do fluxo de nutrientes no ecossistema, os quais são afetados pelas técnicas de manejo utilizadas. O objetivo deste trabalho foi avaliar diferenças na ciclagem e no balanço de C e nutrientes, em plantio puro e misto de espécies florestais nativas, bem como em fragmentos florestais de Mata Atlântica. O trabalho foi desenvolvido em solos de tabuleiro do sudeste da Bahia, Brasil, no período de agosto de 1994 a julho de 1995, em plantios, com 22 anos de idade, de pau-roxo, Peltogyne angustiflora; putumuju, Centrolobium robustum; arapati, Arapatiella psilophylla; arapaçu, Sclerolobium chrysophyllum; claraíba, Cordia trichotoma; e óleo-comumbá, Macrolobium latifolium. Como referências, foram utilizadas uma floresta secundária, praticamente em estado clímax, e uma capoeira de 40 anos de idade. As quantidades totais de carbono e nutrientes no sistema (solo + parte aérea + serapilheira variou marcadamente entre as espécies florestais. O plantio misto apresentou maior acúmulo desses elementos do que os plantios puros. O plantio misto apresentou maior intensidade de ciclagem bioquímica para todos os nutrientes do que a média dos plantios puros. Resultado similar ocorreu para a ciclagem biogeoquímica, à exceção de Ca. O balanço de C, P e K foi negativo em todas as coberturas florestais; entretanto, para N o balanço foi positivo. O balanço de Ca foi positivo apenas para o arapaçu, enquanto o de Mg foi negativo somente no putumuju e óleo-comumbá. O balanço mais negativo foi de P, seguido de K e Ca. O plantio misto apresentou balanço próximo à média dos plantios puros. Desse modo, o plantio misto mostrou-se mais adequado, por proporcionar, simultaneamente, maior eficiência da ciclagem bioquímica e biogeoquímica e balanços mais equilibrados de carbono e nutrientes.This study aimed to evaluate the differences in carbon and nutrient cycling and balance in two

Intra-Household Allocation of Nutrients in an Opening China

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Li Zhou

2018-04-01

Full Text Available This paper uses China Health and Nutrition Survey (CHNS data to analyze the effect of foreign direct investment (FDI on nutrient intakes across various family roles to identify the different family roles’ heterogeneous nutrition intake responses to economic openness. The empirical evidence shows that FDI enhances labor forces’ calorie intake significantly, especially for rural households. The government should continue facilitating more FDI inflows, especially FDI in secondary industries for rural populations. However, the larger the family, the smaller the effect of FDI on nutrient intake for some family roles. The elderly and children may be weaker responders on nutrient intake than other family members in an open economy. This implies the existence of intra-household redistribution and that the level of effectiveness will decrease with family size. The results suggest that family members in rural areas can benefit more in terms of nutrient intake. Our empirical evidence also indicates that female family members’ calorie intake from the FDI effect is higher than that of male family members (except for the granddaughter/grandson. Preferential policies should be provided for the FDI, flowing to rural areas and female dominant industries.

Understanding the influence of nutrients on stream ecosystems in agricultural landscapes

Science.gov (United States)

Munn, Mark D.; Frey, Jeffrey W.; Tesoriero, Anthony J.; Black, Robert W.; Duff, John H.; Lee, Kathy E.; Maret, Terry R.; Mebane, Christopher A.; Waite, Ian R.; Zelt, Ronald B.

2018-06-06

Sustaining the quality of the Nation’s water resources and the health of our diverse ecosystems depends on the availability of sound water-resources data and information to develop effective, science-based policies. Effective management of water resources also brings more certainty and efficiency to important economic sectors. Taken together, these actions lead to immediate and long-term economic, social, and environmental benefits that make a difference to the lives of the almost 400 million people projected to live in the United States by 2050.In 1991, Congress established the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) to address where, when, why, and how the Nation’s water quality has changed, or is likely to change in the future, in response to human activities and natural factors. Since then, NAWQA has been a leading source of scientific data and knowledge used by national, regional, State, and local agencies to develop science-based policies and management strategies to improve and protect water resources used for drinking water, recreation, irrigation, energy development, and ecosystem needs (https://water.usgs.gov/nawqa/applications/). Plans for the third decade of NAWQA (2013–23) address priority water-quality issues and science needs identified by NAWQA stakeholders, such as the Advisory Committee on Water Information and the National Research Council, and are designed to meet increasing challenges related to population growth, increasing needs for clean water, and changing land-use and weather patterns.Excess nutrients are a pervasive problem of streams, lakes, and coastal waters. The current report, “The Quality of Our Nation’s Waters—Understanding the Effects of Nutrients on Stream Ecosystems in Agricultural Landscapes,” presents a summary of results from USGS investigations conducted from 2003 to 2011 on processes that influence nutrients and how nutrient enrichment can alter biological components of

Leaf absorption of mineral nutrients in carnivorous plants stimulates root nutrient uptake

Czech Academy of Sciences Publication Activity Database

Adamec, Lubomír

2002-01-01

Roč. 155, - (2002), s. 89-100 ISSN 0028-646X R&D Projects: GA AV ČR IAA6005905 Institutional research plan: CEZ:AV0Z6005908 Keywords : terrestrial carnivorous plant s * utilization of prey * mineral nutrient re-utilization * leaf nutrient supply Subject RIV: EF - Botanics Impact factor: 2.945, year: 2002

CADDIS Volume 2. Sources, Stressors and Responses: Nutrients

Science.gov (United States)

Introduction to the nutrients module, when to list nutrients as a candidate cause, ways to measure nutrients, simple and detailed conceptual diagrams for nutrients, nutrients module references and literature reviews.

A role for N-acetylglucosamine as a nutrient sensor and mediator of insulin resistance.

Science.gov (United States)

Wells, L; Vosseller, K; Hart, G W

2003-02-01

The ability to regulate energy balance at both the cellular and whole body level is an essential process of life. As western society has shifted to a higher caloric diet and more sedentary lifestyle, the incidence of type 2 diabetes (non-insulin-dependent diabetes mellitus) has increased to epidemic proportions. Thus, type 2 diabetes has been described as a disease of 'chronic overnutrition'. There are abundant data to support the relationship between nutrient availability and insulin action. However, there have been multiple hypotheses and debates as to the mechanism by which nutrient availability modulates insulin signaling and how excess nutrients lead to insulin resistance. One well-established pathway for nutrient sensing is the hexosamine biosynthetic pathway (HSP), which produces the acetylated aminosugar nucleotide uridine 5'-diphospho-N-acetylglucosamine (UDP-Glc-NAc) as its end product. Since UDP-GlcNAc is the donor substrate for modification of nucleocytoplasmic proteins at serine and threonine residues with N-acetylglucosamine (O-GlcNAc), the possibility of this posttranslational modification serving as the nutrient sensor has been proposed. We have recently directly tested this model in adipocytes by examining the effect of elevated levels of O-GlcNAc on insulin-stimulated glucose uptake. In this review, we summarize the existing work that implicates the HSP and O-GlcNAc modification as nutrient sensors and regulators of insulin signaling.

Groundwater – The disregarded component in lake water and nutrient budgets. Part 2: effects of groundwater on nutrients

Science.gov (United States)

Lewandowski, Jörg; Meinikmann, Karin; Nützmann, Gunnar; Rosenberry, Donald O.

2015-01-01

Lacustrine groundwater discharge (LGD) transports nutrients from a catchment to a lake, which may fuel eutrophication, one of the major threats to our fresh waters. Unfortunately, LGD has often been disregarded in lake nutrient studies. Most measurement techniques are based on separate determinations of volume and nutrient concentration of LGD: Loads are calculated by multiplying seepage volumes by concentrations of exfiltrating water. Typically low phosphorus (P) concentrations of pristine groundwater often are increased due to anthropogenic sources such as fertilizer, manure or sewage. Mineralization of naturally present organic matter might also increase groundwater P. Reducing redox conditions favour P transport through the aquifer to the reactive aquifer-lake interface. In some cases, large decreases of P concentrations may occur at the interface, for example, due to increased oxygen availability, while in other cases, there is nearly no decrease in P. The high reactivity of the interface complicates quantification of groundwater-borne P loads to the lake, making difficult clear differentiation of internal and external P loads to surface water. Anthropogenic sources of nitrogen (N) in groundwater are similar to those of phosphate. However, the environmental fate of N differs fundamentally from P because N occurs in several different redox states, each with different mobility. While nitrate behaves essentially conservatively in most oxic aquifers, ammonium's mobility is similar to that of phosphate. Nitrate may be transformed to gaseous N2 in reducing conditions and permanently removed from the system. Biogeochemical turnover of N is common at the reactive aquifer-lake interface. Nutrient loads from LGD were compiled from the literature. Groundwater-borne P loads vary from 0.74 to 2900 mg PO4-P m−2 year−1; for N, these loads vary from 0.001 to 640 g m−2 year−1. Even small amounts of seepage can carry large nutrient loads due to often high

Long Term Large Scale river nutrient changes across the UK

Science.gov (United States)

Bell, Victoria; Naden, Pam; Tipping, Ed; Davies, Helen; Davies, Jessica; Dragosits, Ulli; Muhammed, Shibu; Quinton, John; Stuart, Marianne; Whitmore, Andy; Wu, Lianhai

2017-04-01

During recent decades and centuries, pools and fluxes of Carbon, Nitrogen and Phosphorus (C, N and P) in UK rivers and ecosystems have been transformed by the spread and fertiliser-based intensification of agriculture (necessary to sustain human populations), by atmospheric pollution, by human waste (rising in line with population growth), and now by climate change. The principal objective of the UK's NERC-funded Macronutrients LTLS research project has been to account for observable terrestrial and aquatic pools, concentrations and fluxes of C, N and P on the basis of past inputs, biotic and abiotic interactions, and transport processes. More specifically, over the last 200 years, what have been the temporal responses of plant and soil nutrient pools in different UK catchments to nutrient enrichment, and what have been the consequent effects on nutrient transfers from land to the atmosphere, freshwaters and estuaries? The work described here addresses the second question by providing an integrated quantitative description of the interlinked land and water pools and annual fluxes of C, N and P for UK catchments over time. A national-scale modelling environment has been developed, combining simple physically-based gridded models that can be parameterised using recent observations before application to long timescales. The LTLS Integrated Model (LTLS-IM) uses readily-available driving data (climate, land-use, nutrient inputs, topography), and model estimates of both terrestrial and freshwater nutrient loads have been compared with measurements from sites across the UK. Here, the focus is on the freshwater nutrient component of the LTLS-IM, but the terrestrial nutrient inputs required for this are provided by models of nutrient processes in semi-natural and agricultural systems, and from simple models of nutrients arising from human waste. In the freshwater model, lateral routing of dissolved and particulate nutrients and within-river processing such as

Potential of diatom consortium developed by nutrient enrichment for biodiesel production and simultaneous nutrient removal from waste water

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Thomas Kiran Marella

2018-05-01

Full Text Available Because of the decreasing fossil fuel supply and increasing greenhouse gas (GHG emissions, microalgae have been identified as a viable and sustainable feedstock for biofuel production. The major effect of the release of wastewater rich in organic compounds has led to the eutrophication of freshwater ecosystems. A combined approach of freshwater diatom cultivation with urban sewage water treatment is a promising solution for nutrient removal and biofuel production. In this study, urban wastewater from eutrophic Hussain Sagar Lake was used to cultivate a diatom algae consortium, and the effects of silica and trace metal enrichment on growth, nutrient removal, and lipid production were evaluated. The nano-silica-based micronutrient mixture Nualgi containing Si, Fe, and metal ions was used to optimize diatom growth. Respectively, N and P reductions of 95.1% and 88.9%, COD and BOD reductions of 91% and 51% with a biomass yield of 122.5 mg L−1 day−1 and lipid productivity of 37 mg L−1 day−1 were observed for cultures grown in waste water using Nualgi. Fatty acid profiles revealed 13 different fatty acids with slight differences in their percentage of dry cell weight (DCW depending on enrichment level. These results demonstrate the potential of diatom algae grown in wastewater to produce feedstock for renewable biodiesel production. Enhanced carbon and excess nutrient utilization makes diatoms ideal candidates for co-processes such as CO2 sequestration, biodiesel production, and wastewater phycoremediation. Keywords: Micro algae, Diatom, Biodiesel, Nualgi, Nutrient removal, Wastewater

A Comparative-Study on Nutrient Cycling in Wet Heathland Ecosystems.2.Litter Decomposition and Nutrient Mineralization

NARCIS (Netherlands)

Berendse, F.; Bobbink, R.; Rouwenhorst, G.

1989-01-01

The concept of the relative nutrient requirement (L n) that was introduced in the first paper of this series is used to analyse the effects of the dominant plant population on nutrient cycling and nutrient mineralization in wet heathland ecosystems. A distinction is made between the effect that the

Nutrient patterns and their food sources in an International Study Setting: report from the EPIC study.

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Aurelie Moskal

Full Text Available Compared to food patterns, nutrient patterns have been rarely used particularly at international level. We studied, in the context of a multi-center study with heterogeneous data, the methodological challenges regarding pattern analyses.We identified nutrient patterns from food frequency questionnaires (FFQ in the European Prospective Investigation into Cancer and Nutrition (EPIC Study and used 24-hour dietary recall (24-HDR data to validate and describe the nutrient patterns and their related food sources. Associations between lifestyle factors and the nutrient patterns were also examined. Principal component analysis (PCA was applied on 23 nutrients derived from country-specific FFQ combining data from all EPIC centers (N = 477,312. Harmonized 24-HDRs available for a representative sample of the EPIC populations (N = 34,436 provided accurate mean group estimates of nutrients and foods by quintiles of pattern scores, presented graphically. An overall PCA combining all data captured a good proportion of the variance explained in each EPIC center. Four nutrient patterns were identified explaining 67% of the total variance: Principle component (PC 1 was characterized by a high contribution of nutrients from plant food sources and a low contribution of nutrients from animal food sources; PC2 by a high contribution of micro-nutrients and proteins; PC3 was characterized by polyunsaturated fatty acids and vitamin D; PC4 was characterized by calcium, proteins, riboflavin, and phosphorus. The nutrients with high loadings on a particular pattern as derived from country-specific FFQ also showed high deviations in their mean EPIC intakes by quintiles of pattern scores when estimated from 24-HDR. Center and energy intake explained most of the variability in pattern scores.The use of 24-HDR enabled internal validation and facilitated the interpretation of the nutrient patterns derived from FFQs in term of food sources. These outcomes open research

Lake nutrient stoichiometry is less predictable than nutrient concentrations at regional and sub-continental scales.

Science.gov (United States)

Collins, Sarah M; Oliver, Samantha K; Lapierre, Jean-Francois; Stanley, Emily H; Jones, John R; Wagner, Tyler; Soranno, Patricia A

2017-07-01

Production in many ecosystems is co-limited by multiple elements. While a known suite of drivers associated with nutrient sources, nutrient transport, and internal processing controls concentrations of phosphorus (P) and nitrogen (N) in lakes, much less is known about whether the drivers of single nutrient concentrations can also explain spatial or temporal variation in lake N:P stoichiometry. Predicting stoichiometry might be more complex than predicting concentrations of individual elements because some drivers have similar relationships with N and P, leading to a weak relationship with their ratio. Further, the dominant controls on elemental concentrations likely vary across regions, resulting in context dependent relationships between drivers, lake nutrients and their ratios. Here, we examine whether known drivers of N and P concentrations can explain variation in N:P stoichiometry, and whether explaining variation in stoichiometry differs across regions. We examined drivers of N:P in ~2,700 lakes at a sub-continental scale and two large regions nested within the sub-continental study area that have contrasting ecological context, including differences in the dominant type of land cover (agriculture vs. forest). At the sub-continental scale, lake nutrient concentrations were correlated with nutrient loading and lake internal processing, but stoichiometry was only weakly correlated to drivers of lake nutrients. At the regional scale, drivers that explained variation in nutrients and stoichiometry differed between regions. In the Midwestern U.S. region, dominated by agricultural land use, lake depth and the percentage of row crop agriculture were strong predictors of stoichiometry because only phosphorus was related to lake depth and only nitrogen was related to the percentage of row crop agriculture. In contrast, all drivers were related to N and P in similar ways in the Northeastern U.S. region, leading to weak relationships between drivers and stoichiometry

Leaf nutrient resorption, leaf lifespan and the retention of nutrients in seagrass systems

NARCIS (Netherlands)

Hemminga, M.A.; Marbà, N.; Stapel, J.

1999-01-01

Efficient nutrient resorption from senescing leaves, and extended leaf life spans are important strategies in order to conserve nutrients for plants in general. Despite the fact that seagrasses often grow in oligotrophic waters, these conservation strategies are not strongly developed in seagrasses.

Characteristic of Soil Nutrients Loss in Beiyunhe Reservoir Under the Simulated Rainfall

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LIU Cao

2016-05-01

Full Text Available Field nutrient loss from soil became the major factor of the water pollution control in countryside in China. Beiyunhe reservoir is located in semiarid zone, where field nutrient loss distributed in summer. To assess the flied nutrient loss in Beiyunhe reservoir, we conducted experiments to study the characteristic of soil nutrients loss by analysis of the content of runoff water, soil nutrients and runoff water sediment under simulated rainfall. The results showed that the runoff happened in the rainstorm. In runoff water, the content of TN was 4.7~11.3 mg·L-1, ammonia nitrogen and nitrate nitrogen accounted for 44.51% of TN; the content of P was 0.66~1.35 mg·L-1, water soluble phosphorus accounted for 54.08% of TP. And the main loss of nutrients was in the surface soil, the loss of TN, NH4+-N, NO3--N, TP and DP were 29.79%, 52.09%, 10.21%, 16.48% and 5.27%, respectively. However, the most of field nutrient loss were in runoff sediment, the content of TN and TP were 0.66~1.27 mg·g-1 and 14.73~20 mg·g-1 in sediment, and TN and TP account for 82.28% and 99.89% of total loss of nutrient. After the rainstorm, the macro-aggregates were reduced 8.8%, and the micro-aggregates increased 9.5%.

Octopamine connects nutrient cues to lipid metabolism upon nutrient deprivation.

Science.gov (United States)

Tao, Jun; Ma, Yi-Cheng; Yang, Zhong-Shan; Zou, Cheng-Gang; Zhang, Ke-Qin

2016-05-01

Starvation is probably the most common stressful situation in nature. In vertebrates, elevation of the biogenic amine norepinephrine levels is common during starvation. However, the precise role of norepinephrine in nutrient deprivation remains largely unknown. We report that in the free-living nematode Caenorhabditis elegans, up-regulation of the biosynthesis of octopamine, the invertebrate counterpart of norepinephrine, serves as a mechanism to adapt to starvation. During nutrient deprivation, the nuclear receptor DAF-12, known to sense nutritional cues, up-regulates the expression of tbh-1 that encodes tyramine β-hydroxylase, a key enzyme for octopamine biosynthesis, in the RIC neurons. Octopamine induces the expression of the lipase gene lips-6 via its receptor SER-3 in the intestine. LIPS-6, in turn, elicits lipid mobilization. Our findings reveal that octopamine acts as an endocrine regulator linking nutrient cues to lipolysis to maintain energy homeostasis, and suggest that such a mechanism may be evolutionally conserved in diverse organisms.

Temporal Analyses of the Response of Intervertebral Disc Cells and Mesenchymal Stem Cells to Nutrient Deprivation

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Sarah A. Turner

2016-01-01

Full Text Available Much emphasis has been placed recently on the repair of degenerate discs using implanted cells, such as disc cells or bone marrow derived mesenchymal stem cells (MSCs. This study examines the temporal response of bovine and human nucleus pulposus (NP cells and MSCs cultured in monolayer following exposure to altered levels of glucose (0, 3.15, and 4.5 g/L and foetal bovine serum (0, 10, and 20% using an automated time-lapse imaging system. NP cells were also exposed to the cell death inducers, hydrogen peroxide and staurosporine, in comparison to serum starvation. We have demonstrated that human NP cells show an initial “shock” response to reduced nutrition (glucose. However, as time progresses, NP cells supplemented with serum recover with minimal evidence of cell death. Human NP cells show no evidence of proliferation in response to nutrient supplementation, whereas MSCs showed greater response to increased nutrition. When specifically inducing NP cell death with hydrogen peroxide and staurosporine, as expected, the cell number declined. These results support the concept that implanted NP cells or MSCs may be capable of survival in the nutrient-poor environment of the degenerate human disc, which has important clinical implications for the development of IVD cell therapies.

Hydrothermal carbonization of food waste for nutrient recovery and reuse.

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Idowu, Ifeolu; Li, Liang; Flora, Joseph R V; Pellechia, Perry J; Darko, Samuel A; Ro, Kyoung S; Berge, Nicole D

2017-11-01

Food waste represents a rather large and currently underutilized source of potentially available and reusable nutrients. Laboratory-scale experiments evaluating the hydrothermal carbonization of food wastes collected from restaurants were conducted to understand how changes in feedstock composition and carbonization process conditions influence primary and secondary nutrient fate. Results from this work indicate that at all evaluated reaction times and temperatures, the majority of nitrogen, calcium, and magnesium remain integrated within the solid-phase, while the majority of potassium and sodium reside in the liquid-phase. The fate of phosphorus is dependent on reaction times and temperatures, with solid-phase integration increasing with higher reaction temperature and longer time. A series of leaching experiments to determine potential solid-phase nutrient availability were also conducted and indicate that, at least in the short term, nitrogen release from the solids is small, while almost all of the phosphorus present in the solids produced from carbonizing at 225 and 250°C is released. At a reaction temperature of 275°C, smaller fractions of the solid-phase total phosphorus are released as reaction times increase, likely due to increased solids incorporation. Using these data, it is estimated that up to 0.96% and 2.30% of nitrogen and phosphorus-based fertilizers, respectively, in the US can be replaced by the nutrients integrated within hydrochar and liquid-phases generated from the carbonization of currently landfilled food wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trophic categorization in the Rías Baixas (NW Spain: nutrients in water and in macroalgae

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Rubén Villares

2006-03-01

Full Text Available Marine eutrophication caused by an excess supply of nutrients is a serious problem in many coastal areas throughout the world. In the present study we used the capacity of macroalgae (Ulva and Enteromorpha to integrate the nutrient regime of a water body in order to examine the trophic categorization in the embayments studied. We found that the trophic categorization established based on nutrient levels in macroalgae differed from that established based on concentrations in the water. The waters of the innermost areas of the inlets were the most nutrient enriched; the algae appeared to be more affected by specific local conditions and did not display the gradient of decreasing nutrient concentrations from inner to outer areas that was observed in the water samples. The lack of correspondence between nutrients in the water and in the algae in the present study may have been due to the heterogeneous nutrient conditions found in coastal areas, so that the intertidal algae did not adequately reflect the nutrient levels of the inner zones of the embayments under study.

Relation of watershed setting and stream nutrient yields at selected sites in central and eastern North Carolina, 1997-2008

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Harden, Stephen L.; Cuffney, Thomas F.; Terziotti, Silvia; Kolb, Katharine R.

2013-01-01

Data collected between 1997 and 2008 at 48 stream sites were used to characterize relations between watershed settings and stream nutrient yields throughout central and eastern North Carolina. The focus of the investigation was to identify environmental variables in watersheds that influence nutrient export for supporting the development and prioritization of management strategies for restoring nutrient-impaired streams. Nutrient concentration data and streamflow data compiled for the 1997 to 2008 study period were used to compute stream yields of nitrate, total nitrogen (N), and total phosphorus (P) for each study site. Compiled environmental data (including variables for land cover, hydrologic soil groups, base-flow index, streams, wastewater treatment facilities, and concentrated animal feeding operations) were used to characterize the watershed settings for the study sites. Data for the environmental variables were analyzed in combination with the stream nutrient yields to explore relations based on watershed characteristics and to evaluate whether particular variables were useful indicators of watersheds having relatively higher or lower potential for exporting nutrients. Data evaluations included an examination of median annual nutrient yields based on a watershed land-use classification scheme developed as part of the study. An initial examination of the data indicated that the highest median annual nutrient yields occurred at both agricultural and urban sites, especially for urban sites having large percentages of point-source flow contributions to the streams. The results of statistical testing identified significant differences in annual nutrient yields when sites were analyzed on the basis of watershed land-use category. When statistical differences in median annual yields were noted, the results for nitrate, total N, and total P were similar in that highly urbanized watersheds (greater than 30 percent developed land use) and (or) watersheds with greater

Nutrient surpluses on integrated arable farms

NARCIS (Netherlands)

Schröder, J.J.; Asperen, van P.; Dongen, van G.J.M.; Wijnands, F.G.

1996-01-01

From 1990 to 1993 nutrient fluxes were monitored on 38 private arable farms that had adopted farming strategies aiming at reduced nutrient inputs and substitution of mineral fertilizers by organic fertilizers. The nutrient surplus was defined as the difference between inputs (including inputs

Nutrient concentration in leaves, a tool for nutritional diagnosis in cocoa.

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Yina Jazbleidi Puentes-Páramo

2016-06-01

Full Text Available The aim of this study was to estimate the foliar concentrations in cocoa farming (Theobroma cacao L as a diagnostic tool of their nutritional status. At the Research Center of the National Federation of Cocoa Producers (Fedecacao located in Miranda-Cauca, Colombia, the study assessed the effect of five doses of NPK fertilization in nutrient concentration in leaves of four cocoa clones CCN-51, TSH-565, ICS-39, and ICS-95 from 20102012. Experimental design was randomized complete block design with five treatments: TR(control, T1(25% NPK, T2(50% NPK, T3(75% NPK, T4(100% NPK and four replicates. The concentration of 11 nutrients (N, P, K+, Ca2+, S, Mg2+, B, Zn2+, Cu2+, Fe2+, Mn2+ and their relation with yield was evaluated for three years. Results showed differences in the foliar concentration of nutrients assessed by effect of treatments, by clone, and by clone*treatment interaction. The foliar concentration used was derived from higher yield-related treatment, whereby, a proposal for nutritional diagnosis in cocoa based on nutrient monitoring was created to evaluate nutrient concentration in leaves.

Posting point-of-purchase nutrition information in university canteens does not influence meal choice and nutrient intake.

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Hoefkens, Christine; Lachat, Carl; Kolsteren, Patrick; Van Camp, John; Verbeke, Wim

2011-08-01

Growing concern over the relation between out-of-home eating and overweight has triggered the use of point-of-purchase (POP) nutrition information when eating out of the home. In canteens that offer various unhealthy choices, the posting of POP nutrition information has the potential to improve meal choices and dietary intakes. The objective of this study was to increase the proportion of consumed meals that comply with recommendations for energy, saturated fat, sodium, and vegetable content by 5%. A one-group pretest-posttest design was used. A total of 224 customers of 2 university canteens completed a questionnaire used for consumer profiling and 3-d food records to assess their meal choices and nutrient intakes. The 12 best meal combinations received star ratings and descriptors for nutrients or food groups that did not comply. Reported meal choices in canteens and nutrient intakes did not improve after the intervention (P > 0.05). The nutritional profile of the meal choice, obtained from a qualitative and quantitative nutritional assessment of meals, mirrored the nutritional profile of all meals offered (P > 0.05) and not that of the recommended meals offered (P choices were not compensated for later in the day (P > 0.05). The healthiest choices were made by participants with greater objective nutrition knowledge, stronger health and weight-control motives, and a greater openness to change meal choices at baseline (P choices and nutrient intakes. Despite the intervention, meal choices were largely determined by meals offered. Therefore, nutrition-information interventions in canteens may be more effective with a healthier meal supply. This trial was registered at clinicaltrials.gov as NCT01249508.

Nutrient supply of plants in aquaponic systems

OpenAIRE

Bittsánszky, András; Uzinger, Nikolett; Gyulai, Gábor; Mathis, Alex; Junge, Ranka; Villarroel, Morris; Kotzen, Benzion; Komives, Tamas

2016-01-01

In this preliminary article we present data on plant nutrient concentrations in aquaponic systems, and compare them to nutrient concentrations in “standard” hydroponic solutions. Our data shows that the nutrient concentrations supplied by the fish in aquaponic system are significantly lower for most nutrients, compared to hydroponic systems. Nevertheless, plants do thrive in solutions that have lower nutrient levels than “standard” hydroponic solutions. This is especially true for green leafy...

Energy-neutral sustainable nutrient recovery incorporated with the wastewater purification process in an enlarged microbial nutrient recovery cell

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Sun, Dongya; Gao, Yifan; Hou, Dianxun; Zuo, Kuichang; Chen, Xi; Liang, Peng; Zhang, Xiaoyuan; Ren, Zhiyong Jason; Huang, Xia

2018-04-01

Recovery of nutrient resources from the wastewater is now an inevitable strategy to maintain the supply of both nutrient and water for our huge population. While the intensive energy consumption in conventional nutrient recovery technologies still remained as the bottleneck towards the sustainable nutrient recycle. This study proposed an enlarged microbial nutrient recovery cell (EMNRC) which was powered by the energy contained in wastewater and achieved multi-cycle nutrient recovery incorporated with in situ wastewater treatment. With the optimal recovery solution of 3 g/L NaCl and the optimal volume ratio of wastewater to recovery solution of 10:1, >89% of phosphorus and >62% of ammonium nitrogen were recovered into struvite. An extremely low water input ratio of water. It was proved the EMNRC system was a promising technology which could utilize the chemical energy contained in wastewater itself and energy-neutrally recover nutrient during the continuous wastewater purification process.

Response of Vallisneria natans to Increasing Nitrogen Loading Depends on Sediment Nutrient Characteristics

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Jiao Gu

2016-11-01

Full Text Available High nitrogen (N loading may contribute to recession of submerged macrophytes in shallow lakes; yet, its influences vary depending on environmental conditions. In August 2013, we conducted a 28-day factorial-designed field mesocosm experiment in Lake Taihu at the Taihu Laboratory for Lake Ecosystem Research (TLLER to examine the effects of high N loading on the growth of Vallisneria natans in systems with contrasting sediment types. We ran the experiments with two levels of nutrient loading—present-day external nutrient loading (average P: 5 μg·L−1·day−1, N: 130 μg·L−1·day−1 and P: 5 μg·L−1·day−1, and with three times higher N loading (N: 390 μg·L−1·day−1 and used sediment with two contrasting nutrient levels. V. natans growth decreased significantly with increasing N loading, the effect being dependent, however, on the nutrient status of the sediment. In low nutrient sediment, relative growth rates, leaf biomass and root biomass decreased by 11.9%, 18.2% and 23.3%, respectively, at high rather than low N loading, while the decline was larger (44.0%, 32.7% and 41.8%, respectively when using high nutrient sediment. The larger effect in the nutrient-rich sediment may reflect an observed higher shading of phytoplankton and excess nutrient accumulation in plant tissue, though potential toxic effects of the high-nutrient sediment may also have contributed. Our study confirms the occurrence of a negative effect of increasing N loading on submerged plant growth in shallow nutrient-enriched lakes and further shows that this effect is augmented when the plants grow in nutrient-rich sediment. External N control may, therefore, help to protect or restore submerged macrophytes, especially when the sediment is enriched with nutrients and organic matter.

Production of Bacterial Cellulose by Gluconacetobacter hansenii Using Corn Steep Liquor As Nutrient Sources

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Andrea F. S. Costa

2017-10-01

Full Text Available Cellulose is mainly produced by plants, although many bacteria, especially those belonging to the genus Gluconacetobacter, produce a very peculiar form of cellulose with mechanical and structural properties that can be exploited in numerous applications. However, the production cost of bacterial cellulose (BC is very high to the use of expensive culture media, poor yields, downstream processing, and operating costs. Thus, the purpose of this work was to evaluate the use of industrial residues as nutrients for the production of BC by Gluconacetobacter hansenii UCP1619. BC pellicles were synthesized using the Hestrin–Schramm (HS medium and alternative media formulated with different carbon (sugarcane molasses and acetylated glucose and nitrogen sources [yeast extract, peptone, and corn steep liquor (CSL]. A jeans laundry was also tested. None of the tested sources (beside CSL worked as carbon and nutrient substitute. The alternative medium formulated with 1.5% glucose and 2.5% CSL led to the highest yield in terms of dry and hydrated mass. The BC mass produced in the alternative culture medium corresponded to 73% of that achieved with the HS culture medium. The BC pellicles demonstrated a high concentration of microfibrils and nanofibrils forming a homogenous, compact, and three-dimensional structure. The biopolymer produced in the alternative medium had greater thermal stability, as degradation began at 240°C, while degradation of the biopolymer produced in the HS medium began at 195°C. Both biopolymers exhibited high crystallinity. The mechanical tensile test revealed the maximum breaking strength and the elongation of the break of hydrated and dry pellicles. The dry BC film supported up to 48 MPa of the breaking strength and exhibited greater than 96.98% stiffness in comparison with the hydrated film. The dry film supported up to 48 MPa of the breaking strength and exhibited greater than 96.98% stiffness in comparison with the hydrated film

Modelling concept of lettuce breeding for nutrient efficiency

NARCIS (Netherlands)

Kerbiriou, P.J.; Stomph, T.J.; Lammerts Van Bueren, E.; Struik, P.C.

2014-01-01

Modern lettuce cultivars are bred for use under high levels of input of water and nutrients, and therefore less adapted to low-input or organic conditions in which nitrate availability varies over time and within the soil profile. To create robust cultivars it is necessary to assess which traits

Influences of Moisture Regimes and Functional Plant Types on Nutrient Cycling in Permafrost Regions

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McCaully, R. E.; Arendt, C. A.; Newman, B. D.; Heikoop, J. M.; Wilson, C. J.; Sevanto, S.; Wales, N. A.; Wullschleger, S.

2017-12-01

In the permafrost-dominated Arctic, climatic feedbacks exist between permafrost, soil moisture, functional plant type and presence of nutrients. Functional plant types present within the Arctic regulate and respond to changes in hydrologic regimes and nutrient cycling. Specifically, alders are a member of the birch family that use root nodules to fix nitrogen, which is a limiting nutrient strongly linked to fertilizing Arctic ecosystems. Previous investigations in the Seward Peninsula, AK show elevated presence of nitrate within and downslope of alder patches in degraded permafrost systems, with concentrations an order of magnitude greater than that of nitrate measured above these patches. Further observations within these degraded permafrost systems are crucial to assess whether alders are drivers of, or merely respond to, nitrate fluxes. In addition to vegetative feedbacks with nitrate supply, previous studies have also linked low moisture content to high nitrate production. Within discontinuous permafrost regions, the absence of permafrost creates well-drained regions with unsaturated soils whereas the presence of permafrost limits vertical drainage of soil-pore water creating elevated soil moisture content, which likely corresponds to lower nitrate concentrations. We investigate these feedbacks further in the Seward Peninsula, AK, through research supported by the United States Department of Energy Next Generation Ecosystem Experiment (NGEE) - Arctic. Using soil moisture and thaw depth as proxies to determine the extent of permafrost degradation, we identify areas of discontinuous permafrost over a heterogeneous landscape and collect co-located soilwater chemistry samples to highlight the complex relationships that exist between alder patches, soil moisture regimes, the presence of permafrost and available nitrate supply. Understanding the role of nitrogen in degrading permafrost systems, in the context of both vegetation present and soil moisture, is crucial