Siga este link para ver outros tipos de publicações sobre o tema: Nutrient losses.
Artigos de revistas sobre o tema "Nutrient losses"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores artigos de revistas para estudos sobre o assunto "Nutrient losses".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja os artigos de revistas das mais diversas áreas científicas e compile uma bibliografia correta.
1
Illukpitiy, Prabodh, e Jason P. DeKoff. "An Economic Assessment of Nutrient Removal from Switchgrass Production". Research in Applied Economics 11, n.º 2 (30 de junho de 2019): 26. http://dx.doi.org/10.5296/rae.v11i2.14998.
Texto completo da fonteResumo:
The on-site loss of nutrients due to biomass removal creates additional costs for ethanol production however this aspect has not been properly incorporated in economic analyses of biomass production and processing. This study investigates costs of on-site nutrient losses in switchgrass fields in Tennessee. The replacement cost methodology was applied to measure on-site cost of nutrient losses due to biomass removal and was based on the costs of replacing nutrients removed from the production site. The estimated costs for total on-site nutrient loss due to biomass removal show a substantial loss of nutrients in switchgrass fields. The loss of major nutrients from biomass removal represents the major part of on-site economic costs. A declining trend of nutrient costs per Mg of harvested biomass was observed with increasing in harvesting time. The internalization of on-site costs of nutrient losses is possible by adopting an appropriate harvest schedule for switchgrass.
2
Bertol, Ildegardis, Eloy Lemos Mello, Jean Cláudio Guadagnin, Almir Luis Vedana Zaparolli e Marcos Roberto Carrafa. "Nutrient losses by water erosion". Scientia Agricola 60, n.º 3 (2003): 581–86. http://dx.doi.org/10.1590/s0103-90162003000300025.
Texto completo da fonteResumo:
Water erosion causes soil degradation, which is closely related to nutrient losses either in, the soluble form or adsorbed to soil particles, depending mainly on the adopted soil management system. This study was carried out in São José do Cerrito, SC, Brazil, between March 2000 and June 2001. The objective was to quantify available nitrogen, phosphorus, potassium, calcium and magnesium losses in water erosion obtained with simulated rainfall in the following soil management systems: conventional tillage with no-crop (bare soil) (BS), conventional tillage with soybean (CT), reduced tillage with soybean (RT), no tillage with soybean on a desiccated and burned natural pasture (DBNP), and no tillage with soybean on a desiccated natural pasture (DNP). A rotating boom rainfall simulator was used to perform three rainfall tests with constant intensity of 64 mm h-1 and sufficient duration to reach constant runoff rate, on a clayey-loam, well-structured Typic Hapludox, with an average slope of 0.18 m m-1. The first test was carried out five days before soybean emergence and the second and third at 30 and 60 days, respectively. The nutrient concentration in water and total losses of nitrogen, phosphorus, potassium, calcium and magnesium were higher under CT than in the other soil management systems.
3
Kronvang, B., P. Græsbøll, S. E. Larsen, L. M. Svendsen e H. E. Andersen. "Diffuse nutrient losses in Denmark". Water Science and Technology 33, n.º 4-5 (1 de fevereiro de 1996): 81–88. http://dx.doi.org/10.2166/wst.1996.0491.
Texto completo da fonteResumo:
Since 1989, nutrient loading of the Danish aquatic environment has been monitored in 270 Danish streams draining catchment areas differing in climate, physico-geographic and land usage. Diffuse nutrient loading from non-point sources (mainly agricultural) is now the main cause of eutrophication of the Danish aquatic environment; thus in 1993, diffuse sources accounted for 94% of riverine nitrogen loading and 52% of riverine phosphorus loading. Annual riverine total nitrogen (total-N) loading from diffuse sources during the period 1989-93 was on average 10 times greater in 66 small agricultural catchments (median 23.4 kg N ha−1) than in 9 natural catchments (median 2.2 kg N ha−1). Correspondingly, annual riverine total phosphorus (total-P) loading from diffuse sources was on average 3.5 times greater in the agricultural catchments (0.29 kg P ha−1) than in the natural catchments (0.07 kg P ha−1). The annual total-N and total-P load was found to increase with the proportion of agricultural land in the catchments. In 1993, intensive measurements of phosphorus load in 8 agricultural catchments showed that normal point sampling (fortnightly) underestimates annual total-P loading by a median of 37% as compared to that estimated by frequent sampling. Moreover, estimates of monthly total-P loading are even more biased, especially in late summer and early autumn (−50% to −65%).
4
Hargrave, A. P., e C. F. Shaykewich. "Rainfall induced nitrogen and phosphorus losses from Manitoba soils". Canadian Journal of Soil Science 77, n.º 1 (1 de fevereiro de 1997): 59–65. http://dx.doi.org/10.4141/s95-034.
Texto completo da fonteResumo:
Losses of total sediment phosphorus, total sediment nitrogen and dissolved nitrite, nitrate and ammonium resulting from natural rainfall erosion were studied in southern Manitoba during the summers of 1988–1990. Soils used were a Gretna clay, Leary sandy loam, Ryerson sandy clay and a Carroll clay loam. "Standard" erosion plots, i.e 22.13 m slope length, 4.6 m wide on a 9% slope were used. Crop management systems were 1) alfalfa, 2) corn, 3) wheat – minimum tillage, 4) wheat – conventional tillage, and 5) fallow. Nutrient losses averaged over the study period were greatest from the corn and fallow treatments, as high as 160 kg ha−1 yr−1 for nitrogen and 70 kg ha−1 yr−1 for phosphorus. Losses from wheat were intermediate. Losses from alfalfa were negligible. Most of the nutrient losses occurred with the sediment fraction, a result consistent with previous studies. Thus, nutrient loss can be estimated from a knowledge of soil loss. The amount of nutrient loss per unit soil varied with soil, and was a function of the inherent nutrient status of the soil. Key words: Nitrogen, phosphorus, rainfall erosion, nutrients
5
Wang, Hongxing, Dongsheng Chen e Xiaomei Sun. "Nutrient Allocation to Different Compartments of Age-Sequence Larch Plantations in China". Forests 10, n.º 9 (3 de setembro de 2019): 759. http://dx.doi.org/10.3390/f10090759.
Texto completo da fonteResumo:
Increased demand for forest-derived biomass has led to more intensive harvesting practices. However, the export of large nutrient quantities with the harvested biomass may lead to the depletion of soil nutrients. Therefore, improved knowledge concerning macronutrient allocation (N, P, K, Ca, and Mg) to different components in forests along age sequences is crucial for their sustainable management. In this study, we quantified nutrient allocation to different ecosystem components, including trees, understorey, forest floor, and different soil depths within a chronosequence (6-, 15-, 23-, and 35-year-old) of larch plantations in China. We then assessed the danger of significant nutrient losses from whole tree harvesting (WTH). Nutrient amounts in trees increased with stand age due to an increase in biomass. Stems accounted for 59%–72% of tree biomass and contained 40%–50% of total tree nutrients in the 15- to 35-year-old stands. The forest floor’s nutrient quantities increased from the 6- to 23-year-old stands and then decreased in the 35-year-old plantations. Conversely, most soil indicators initially declined from 15- to 23-year-old stands and then increased in the 35-year-old stand. The total nutrient stocks were greatest in the soil (0–40 cm), which accounted for about 93%–99% of total nutrients in the larch ecosystem. These data indicate that WTH causes nutrient losses about 2.0–2.5 times higher than stem-only harvesting, when thinning 15- or clear-cut harvesting 23- and 35-year-old stands. However, nutrient losses by WTH have little effect on the soil nutrient pools. Prolonging the crop cycle of larch plantations may be beneficial to improve nutrient return through litterfall and allow available soil nutrients to recover.
6
Buescher, Ron. "Changes in Nutritional Value of Horticultural Food Crops Affected by Handling, Storage, and Processing". HortScience 31, n.º 4 (agosto de 1996): 697a—697. http://dx.doi.org/10.21273/hortsci.31.4.697a.
Texto completo da fonteResumo:
Postharvest handling, storage, and processing greatly affect retention and bioavailability of nutrients in horticultural food crops. Although there are a few exceptions, concentrations of most nutrients are reduced by all postharvest operations. Losses of certain nutrients may range from 5% to 100%, depending on their chemical stability, solubility, and postharvest treatment. Therefore, the amount of a particular nutrient in a horticultural food at the time of harvest may not reflect the amount present when the raw or cooked food is consumed. Most vitamins are susceptible to oxidation catalyzed by enzymes, light, pro-oxidant metals, and active oxygen species. Also, nutrient retention and stability are affected by heat, leaching, and certain preservatives, such as sulfites. Physical injuries during handling, processing, and preparation for consumption accelerate vitamin degradation. Therefore, nutrient losses may be very large in minimally processed and food service products that are marketed in peeled, sliced, or shredded forms. Other processing methods, such as dehydration, fermentation, freezing, and canning usually result in significant losses in nutrient concentrations. Although processing generally contributes to loss of nutrient content of foods, certain processing methods improve the bioavailability of some minerals and vitamins, which may increase the actual nutritional value of the food. Methods to reduce inhibitors and antagonists of nutrient availability should receive major emphasis in efforts to improve nutritional value, along with efforts to improve the amount and retention of nutrients in horticultural food crops.
7
Li, Hanzhi, Dengxing Fan, Jianzhi Niu, Guodong Jia, Jiamei Sun, Xinxiao Yu e Linus Zhang. "Effect of rock fragment cover on nutrient loss under varied rainfall intensities: a laboratory study". Hydrology Research 49, n.º 2 (10 de novembro de 2017): 390–406. http://dx.doi.org/10.2166/nh.2017.026.
Texto completo da fonteResumo:
Abstract Surface rock fragments retard overland flow discharge, reduce the runoff generation rate and soil erosion as well as nutrients loss. In Northwest China, a common method for minimizing water, soil, and nutrient losses is the use of rock fragment cover. We used lab stimulation testing to evaluate rock fragment cover efficacy for nutrient conservation. Nutrient losses were determined in both the runoff and sediments under three rain intensities (30, 60 and 90 mm·h−1), four rock fragment covers (0, 10, 20 and 30%) and a slope of 10°. The results showed that rock fragment cover significantly reduced the nutrient losses. Compared with the bare soil control, the rock fragment cover reduced the runoff volume and sediments by 18–38 and 11–69%, respectively, and reduced N and P losses by 9–43 and 16–70%, respectively. These results indicate that rock fragment cover is an effective method for reducing land degradation and improving local environmental conditions.
8
Titus, Brian D., Bruce A. Roberts e Keith W. Deering. "Nutrient removals with harvesting and by deep percolation from white birch (Betula papyrifera [Marsh.]) sites in central Newfoundland". Canadian Journal of Soil Science 78, n.º 1 (1 de fevereiro de 1998): 127–37. http://dx.doi.org/10.4141/s97-044.
Texto completo da fonteResumo:
The effects of conventional stem-only and whole-tree harvesting on nutrient losses in biomass removal and in leachate fluxes over a 3-yr period after cutting three white birch stands in central Newfoundland were determined. Losses of nutrients in biomass were proportionately greater with more intensive harvesting as tree components with higher nutrient concentrations (branches, foliage) were removed. Stem-only harvesting removed 126, 9, 51, 126 and 23 kg ha–1 of N, P, K, Ca and Mg in biomass, respectively. Whole-tree harvesting led to a 19% increase in biomass removal as compared to stem-only harvesting, but nutrient removals with whole-tree harvesting increased by 127% for N, 138% for P, 151% for K, 72% for Ca and 90% for Mg. Nutrient losses in deep percolation of soil solution during the first 3 yr after harvesting were generally greater following stem-only than whole-tree harvesting. This may be the result of increased leaching from slash, increased mineralization beneath slash, and retardation by slash of the successional vegetation that could act as a nutrient sink. In the first 3 yr following harvesting, leaching losses after whole-tree harvesting were 4, 0.2, 8, 23 and 7 kg ha–1 of N, P, K, Ca and Mg, respectively, as compared with 9, 0.1, 7, 28 and 9 kg ha–1 of N, P, K, Ca and Mg after stem-only harvesting. Nutrient losses in leachate were generally small compared to losses in biomass removal. Key words: Intensive harvesting; slash; nutrient budget; sustainable site productivity; Betula papyrifera (Marsh.)
9
Mattson, Neil S., e Marc W. van Iersel. "Application of the “4R” Nutrient Stewardship Concept to Horticultural Crops: Applying Nutrients at the “Right Time”". HortTechnology 21, n.º 6 (dezembro de 2011): 667–73. http://dx.doi.org/10.21273/horttech.21.6.667.
Texto completo da fonteResumo:
The 4R nutrient stewardship framework presents four concepts to consider when applying fertilizers in a responsible matter; the “right source” of nutrients should be applied at the “right rate” during the “right time” and supplied to the “right place” to ensure their uptake. In this article, we provide ideas to consider when attempting to provide nutrients at the right time. When nutrients are applied at a time when they are not required by the plant, the result can be economic and environmental losses. Oversupply relative to plant demand can result in losses of applied nutrients because of leaching or volatilization. Undersupply relative to demand, especially in the case of phloem-immobile nutrients, may limit plant growth and yield. Several factors interact to affect plant nutrient demand such as growth stage, life history (annual vs. perennial), environmental conditions, and plant health. Techniques such as soil and tissue testing, isotopic labeling, and spectral reflectance have been used with varying degrees of success and expense to measure plant nutrient demand and guide fertilizer decisions. Besides knowledge of plant nutrient demand, efficient nutrient supply also depends on systems that allow precise spatial and temporal delivery of nutrients. Future improvements to the timing of nutrient delivery will depend on improvement in knowledge of plant nutrient demands. For example, targeted gene expression chips show promise for use in rapidly assessing plant status for a broad suite of nutrients. Future developments that allow more precise nutrient delivery or more robust agroecosystems that scavenge available nutrients before they are lost to the environment will also help producers use nutrients more efficiently.
10
Hayes, Emma, Suzanne Higgins, Josie Geris e Donal Mullan. "Grassland Reseeding: Impact on Soil Surface Nutrient Accumulation and Using LiDAR-Based Image Differencing to Infer Implications for Water Quality". Agriculture 12, n.º 11 (4 de novembro de 2022): 1854. http://dx.doi.org/10.3390/agriculture12111854.
Texto completo da fonteResumo:
Long-term phosphorus (P) accumulation in agricultural soils presents a challenge for water quality improvement. P is commonly elevated in soils managed for intensive livestock production due to repeated overapplication of slurry and fertilisers. High legacy nutrient accumulations result in poor water quality via transport pathways such as surface runoff, subsurface drainage, and soil erosion. To achieve environmental water quality targets, improved management strategies are required for targeting and reducing excess agricultural P sources. Reseeding of old swards is known to improve grassland productivity and enhance overall soil health. However, soil disturbance associated with reseeding could have positive and negative impacts on other soil functions that affect the nutrient balance (including improved microbial activity, but also increasing the potential for sediment and nutrient losses). This study investigates the impact of reseeding and inversion tillage in addressing soil surface nutrient surpluses and identifies potential trade-offs between production, environment (through soil erosion and associated sediment and nutrient losses), and soil health. At a study site in the Blackwater catchment in Northern Ireland, we collected high-resolution (35 m) gridded soil samples pre- and post-reseeding for nutrient analyses and combined this with GIS-based interpolation. We found that decreases in sub-field scale surface nutrient content (0–7.5 cm depth) occurred following tillage and reseeding, but that this was spatially variable. In addition, the magnitude of changes in nutrient content was variable between P and other sampled nutrients. LiDAR-based image differencing indicated variability in the magnitude of soil erosion and sediment loss also at sub-field scale. Information on the identified deposition and erosion zones (from LiDAR analysis) was combined with mass wasting data to determine accumulation rates and losses of nutrients in-field and confirmed some of the identified patterns in soil surface nutrient content changes post-reseeding. We conclude that while inversion tillage and reseeding are essential agricultural practices, environmental trade-offs exist through potential nutrient and sediment losses. LiDAR-based image differencing was found to be a useful tool in helping to quantify these risks. Quantifying sediment and nutrient losses as a result of inversion tillage and reseeding induced soil erosion aids in understanding potential trends in water quality statuses.
11
Yao, Yiwen, Quanhou Dai, Ruxue Gao, Yixian Gan e Xingsong Yi. "Effects of rainfall intensity on runoff and nutrient loss of gently sloping farmland in a karst area of SW China". PLOS ONE 16, n.º 3 (18 de março de 2021): e0246505. http://dx.doi.org/10.1371/journal.pone.0246505.
Texto completo da fonteResumo:
Nutrient losses from sloping farmland in karst areas lead to the decline in land productivity and nonpoint source pollution. A specially tailored steel channel with an adjustable slope and underground hole fissures was used to simulate the microenvironment of the "dual structure" of the surface and underground of sloping farmland in a karst area. The artificial rainfall simulation method was used to explore the surface and underground runoff characteristics and nutrient losses from sloping farmland under different rainfall intensities. The effect of rainfall intensity on the nutrient loss of farmland on karst sloping land was clarified. The results showed that the surface was the main route of runoff and nutrient loss during the rainy season on sloping farmland in karst areas. The influence of rainfall intensity on the nutrients in surface runoff was more substantial than that on underground runoff nutrients. Nutrient loss was more likely to occur underground than on the surface. The losses of total nitrogen, total phosphorus, and total potassium in surface and underground runoff initially increased and then gradually stabilized with the extension of rainfall duration and increased with increasing rainfall intensity and the amount of nutrient runoff. The output of nutrients through surface runoff accounted for a high proportion of the total, and underground runoff was responsible for a low proportion. Although the amount of nutrients output by underground runoff was small, it could directly cause groundwater pollution. The research results provide a theoretical reference for controlling land source pollution from sloping farming in karst areas.
12
Gross, C. M., J. S. Angle e M. S. Welterlen. "Nutrient and Sediment Losses from Turfgrass". Journal of Environmental Quality 19, n.º 4 (outubro de 1990): 663–68. http://dx.doi.org/10.2134/jeq1990.00472425001900040006x.
Texto completo da fonte
13
van Peer, A. "THE USE OF COMBINED NUTRIENT SYSTEMS TO CONTROL NUTRIENT LOSSES". Acta Horticulturae, n.º 401 (outubro de 1995): 347–50. http://dx.doi.org/10.17660/actahortic.1995.401.41.
Texto completo da fonte
14
Granstedt, Artur. "The potential for Swedish farms to eliminate the use of artificial fertilizers". American Journal of Alternative Agriculture 6, n.º 3 (setembro de 1991): 122–31. http://dx.doi.org/10.1017/s0889189300004070.
Texto completo da fonteResumo:
AbstractThis paper discusses data on plant-nutrient conservation in Sweden between 1950 and 1980 and on plant-nutrient balances in conventional and alternative farming. The amounts of plant nutrients supplied in the form of artificial fertilizer in Sweden increased severalfold between 1950 and 1980. The amounts of N and P applied were four times higher than those recovered in agricultural products. This difference not only represents a loss to farmers but also a burden on the environment. This problem is a consequence of the increased separation of crop management from animal husbandry in Sweden. The flow of plant nutrients through the agroecosystem can be represented as follows: Artificial Fertilizers- > Crop Production-> Animal Husbandry- > Losses (air, water, or immobilization).This paper suggests that all farms in Sweden can operate effectively without relying on applications of highly soluble plant nutrients. By recirculating plant nutrients in manure and cultivating nitrogen-fixing species, the need for artificial fertilizers can be eliminated while minimizing nutrient losses and their associated adverse effects on the environment. Successful alternative farms provide practical examples of how a farming system can eliminate its dependence on applications of highly soluble plant nutrients by stressing effective nutrient economy and biological activity. The strategies they use include: matching animal management practices to the farm's own production of feed, thereby reducing net removal of plant nutrients per unit area (in Sweden 0.6–0.8 animal units per ha); minimizing nutrient losses through careful manure management and by using cover crops; and supplying N by nitrogen-fixing ley species, and P and K by soil weathering and by applying supplementary soil improvement materials.
15
Gillon, D., V. Gomendy, C. Houssard, J. Marechal e JC Valette. "Combustion and Nutrient Losses During Laboratory Burns". International Journal of Wildland Fire 5, n.º 1 (1995): 1. http://dx.doi.org/10.1071/wf9950001.
Texto completo da fonteResumo:
The aim of this study was to assess the effects on combustion characteristics, and their consequences on nutrient losses, of (1) the change in load and packing ratio of the fuel bed, and (2) the change in fuel moisture content. Eighty-one experimental burns were carried out, on a test bench in the laboratory; the fuel was composed of needles and twigs of Pinus pinaster. Two levels of fuel load an dpacking ratio (8t ha-1 needles, packing ratio of 0.040; and 16t ha-1 twigs and needles, packing ratio of 0.066) were compared at constant moisture content (6%); and four levels of moisture content(6%, 12%, 24% and 30% dry weight) were compared at constant fuel load (8t ha-1 needles). At constant moisture content, an increase in the load and packing ratio of the fuel bed led to an increase in the height of flames and in the maximum temperature 25 cm above the fuel bed, in the duration of the rise in temperatures within the fuel, and in the fireline intensity. Conversely, the rate of fire spread decreased. At constant fuel load, an increase in the moisture content of the fuel led to a decrease in the rate of fire spread, in the flame height and the maximum temperature 25 cm above the fuel bed, and in the fireline intensity. In contrast, the maximum temperatures reached within the fuel, when the flaming front was continuous, did not significantly change with varying fuel loads or fuel moisture contents. The percentage fuel consumption was always high, more than 80%, but it significantly decreased with increasing fuel load and packing ratio and with increasing moisture content. Total losses of N, S, and K significantly decreased with increasing fuel load and packing ratio, with increasing moisture content and with decreasing percentage fuel consumption. Losses in P only significantly decreased with increasing fuel load and packing ratio. Losses in Mg and Ca were not significantly affected by fuel load, moisture content. or percentage consumption. An attempt was made to separate volatile from particulate losses, based on the assumption that all the losses of Ca were in particulate form. Whereas losses in particulate form remained relatively constant, losses of nutrients in volatile form seem to have been related to the percentage fuel consumption. Even if these experimental burns were of low intensity (40 to 56 kW m-1), their impact, in terms of lethal temperatures and nutrient losses, was not negligible, particularly for N and P. The increasing fireline intensity with increasing fuel load was not accompanied by an enhancement in the proportion of nutrient losses. In the same way, the strong decrease in fireline intensity with increasing fuel moisture content led only to a slight decrease in some nutrient losses. It was through their effect on the percentage fuel consumption that fuel load or moisture content modified the nutrient losses, particularly volatile losses.
16
Hansen, N. E., D. M. Vietor, C. L. Munster, R. H. White e T. L. Provin. "Runoff and Nutrient Losses from Constructed Soils Amended with Compost". Applied and Environmental Soil Science 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/542873.
Texto completo da fonteResumo:
Composted organic materials used to stabilize roadside embankments in Texas promote rapid revegetation of soils disturbed by construction activities. Yet, adding compost to soil may increase total and soluble plant nutrients available for loss in runoff water. Composted municipal biosolids and dairy manure products were applied to soils in Texas according to prescribed Texas Department of Transportation specifications for stabilizing roadside soils. The specifications included a method for incorporating compost into soils prior to seeding or applying a compost and woodchip mix over a disturbed soil and then seeding. Applying compost and woodchips over the soil surface limited sediment losses (14 to 32 fold decrease) compared to incorporating compost into the soil. Yet, the greatest total phosphorus and nitrogen losses in runoff water occurred from soils where the compost and woodchip mix was applied. The greatest losses of soluble phosphorus also occurred when the compost and woodchip mix was applied. In contrast, nitrate-nitrogen losses in runoff were similar when compost was incorporated in the soil or applied in the woodchip mix. Compost source affected the nutrient losses in runoff. While the composted municipal biosolids added greater nutrient loads to the soil, less nutrient loss in runoff occurred.
17
lital, Arvo, Enn Loigu e Nils Vagstad. "Nutrient Losses and N & P Balances in Small Agricultural Watersheds in Estonia". Hydrology Research 34, n.º 5 (1 de outubro de 2003): 531–42. http://dx.doi.org/10.2166/nh.2003.0023.
Texto completo da fonteResumo:
The paper deals with nutrient runoff monitoring results and calculated nutrient budgets on catchment level in small agricultural watersheds in Estonia. A special programme for monitoring of nutrient losses was initiated and a network of monitoring stations, equipped with data-loggers and suitable devices for continuous flow measurement and flow-proportional automatic water sampling were established in Estonia in the mid-1990s. The research methodology is harmonized with the Nordic countries as well as with the other Baltic countries. The results indicate that nutrients losses are relatively low (generally below 11 kg N/ha and 0.9 kg P/ha). It can be partly explained by drastic changes in the Estonian agricultural practice in the 1990s but also by differences in runoff regime. Nutrient balances were calculated for two catchments, based on the data collected from the farms, some special studies and water quality monitoring results in two watersheds in 1995 (1999) - 2001. The nutrient balances for the catchments turned positive after being negative both for nitrogen and phosphorus in the mid-1990s.
18
Gómez-Rey, M. X., A. Couto-Vázquez, S. García-Marco, J. A. Vega e S. J. González-Prieto. "Reduction of nutrient losses with eroded sediments by post-fire soil stabilisation techniques". International Journal of Wildland Fire 22, n.º 5 (2013): 696. http://dx.doi.org/10.1071/wf12079.
Texto completo da fonteResumo:
After an experimental fire in steep shrubland in a temperate–humid region (north-west Spain), the effects of two post-fire stabilisation treatments (grass seeding and straw mulching) on the chemical properties of eroded sediments, and the amount of nutrients lost with them, were evaluated relative to control burnt soil, over a period of 13 months. Total C and N concentrations, and δ13C, indicated that sediments were mainly contributed by charred plant and litter material. The highest concentrations of extractable base cations in the sediments occurred during the first 3 months following fire, especially for Na and K. As treatments had little or no effect on nutrient concentration in sediments, differences in nutrient losses were due to the 10-fold lower sediment production in mulching compared with other treatments. In control and seeding treatments, the accumulated amounts of nutrients lost with sediments were 989–1028 kg ha–1 (C), 77 kg ha–1 (N), 1.9–2.4 kg ha–1 (Ca), 0.9–1.1 kg ha–1 (Mg), 0.48–0.55 kg ha–1 (NH4+–N), 0.39–0.56 kg ha–1 (K), 0.19–0.34 kg ha–1 (Na) and <0.1 kg ha–1 (P and NO3––N). These values accounted for 22–25% (total C and N) and 5–12% (NH4+–N, Ca, P and Mg) of available nutrients in ash, and 1.0–2.4% of those in ash+topsoil. As nutrient and sediment losses were strongly correlated, the reduction of the latter by mulching application leads to an effective decrease of post-fire nutrient losses.
19
Hallett, R. A., e J. W. Hornbeck. "Managing Oak and Pine Stands on Outwash Sands: Protecting Plant Nutrients". Northern Journal of Applied Forestry 17, n.º 2 (1 de junho de 2000): 57–61. http://dx.doi.org/10.1093/njaf/17.2.57.
Texto completo da fonteResumo:
Abstract In New England, red oak and white pine forests growing on sandy outwash sites are susceptible to nutrient losses due to inherently low nutrient capitals and/or nutrient depletion by past activities such as farming, fire, and intensive harvesting. Key nutrients such as calcium (Ca),magnesium (Mg), and potassium (K) are removed with biomass during harvesting operations, and are lost to increased leaching and erosion during and immediately after logging. In these forests, the highest base saturation or concentration of plant-available Ca, Mg, and K(63 to 92%) is found in the O horizon. As a result, special precautions are needed during harvest to prevent damage and nutrient depletion of the upper soil horizons. To mitigate nutrient losses we recommend using low-impact logging techniques, winter harvesting, and managing for white pine on these sites. North.J. Appl. For. 17(2):57-61.
20
Jones, Michael G., R. Willem Vervoort e Julie Cattle. "Nutrient losses under simulated rainfall from pasture plots in the Great Lakes District, New South Wales". Soil Research 47, n.º 6 (2009): 555. http://dx.doi.org/10.1071/sr08116.
Texto completo da fonteResumo:
Understanding the process by which nutrients and solids enter waterways from pastures in the Great Lakes district, New South Wales, Australia, may assist in maintaining water quality to ensure ongoing environmental and economic sustainability of the region. Rainfall simulations, using a 100-year return storm event, were conducted to determine nutrient and suspended solid concentrations in the runoff of 8 pasture sites in 3 of the catchments in the district. On 5 of the 8 sites, considerable concentrations of N or P were mobilised during the simulated rainfall event, but average nutrient concentrations and total loads across all sites were relatively low and similar to other studies of nutrient runoff from pastures. In addition, low runoff coefficients indicated that runoff is probably not the major pathway for nutrient losses from pasture in this area. Overall, rainfall runoff responses at the sites were similar in the 3 catchments. In contrast, the results suggest that, despite generating more runoff, the sites in the Wang Wauk catchment generated less nutrients in runoff than the sites in the Wallamba and Myall catchments. There was no difference in total suspended solids loads for the sites analysed by catchment. Relationships between soil physical and chemical characteristics and total nutrients loads or cumulative runoff were not strong.
21
Flis, Sally. "4R nutrient stewardship and nitrous oxide losses". Crops & Soils 51, n.º 1 (janeiro de 2018): 10–12. http://dx.doi.org/10.2134/cs2018.51.0106.
Texto completo da fonte
22
Belillas, CM, e MC Feller. "Relationships Between Fire Severity and Atmospheric and Leaching Nutrient Losses in British Columbia's Coastal Western Hemlock Zone Forests". International Journal of Wildland Fire 8, n.º 2 (1998): 87. http://dx.doi.org/10.1071/wf9980087.
Texto completo da fonteResumo:
The relationships between fire severity and fire-induced nutrient losses to the atmosphere and through soil leaching were investigated using small (4m2) plots in logging slash. The study utilized (Pseudotsuga menziesii - Tsuga heterophylla - Thuja plicata) slash in southwestern British Columbia, Canada, in an area where overland flow was negligible. Twenty-two plots containing a range of slash fuel loads were burned, nutrient (N, P, S, K, Mg, and Ca) losses to the atmosphere were measured, and nutrient (N, P, K, ME, and Ca) losses in soil leachate were quantified for the first year postburn. For a given nutrient, total (atmospheric plus leachate) fire-induced losses were similar to atmospheric losses and could be reliably predicted from them due to the relatively low magnitude of leaching losses; Leaching losses were generally poorly related to atmospheric losses. Total, atmospheric, and most leaching losses increased as fire severity (defined as fuel consumption) increased. Nutrient losses were better estimated from fuel consumption variables than they were predicted from fuel load variables. As most of the results of the study were consistent with those of studies conducted elsewhere, these results likely apply to a wider geographic area and range of fire situations than those of the present study. The effort and cost of assessing total fire-induced losses in, at least, North American conifer forests can be minimized, without sacrificing much accuracy, by not measuring fire-induced soil leaching losses, but assuming these are 5-20 kg/ha, depending on the nutrient and the severity of the fire. If nutrient leaching into water bodies is to be quantified, then measurement of leaching losses would be necessary.
23
Machado, Roriz Luciano, Alexander Silva de Resende, Eduardo Francia Carneiro Campello, José Arimathéa Oliveira e Avílio Antônio Franco. "Soil and nutrient losses in erosion gullies at different degrees of restoration". Revista Brasileira de Ciência do Solo 34, n.º 3 (junho de 2010): 945–54. http://dx.doi.org/10.1590/s0100-06832010000300036.
Texto completo da fonteResumo:
The most advanced stage of water erosion, the gully, represents severe problems in different contexts, both in rural and urban environments. In the search for a stabilization of the process in a viable manner it is of utmost importance to assess the efficiency of evaluation methodologies. For this purpose, the efficiency of low-cost conservation practices were tested for the reduction of soil and nutrient losses caused by erosion from gullies in Pinheiral, state of Rio de Janeiro. The following areas were studied: gully recovered by means of physical and biological strategies; gullies in recovering stage, by means of physical strategies only, and gullies under no restoration treatment. During the summer of 2005/2006, the following data sets were collected for this study: soil classification of each of the eroded gully areas; planimetric and altimetric survey; determination of rain erosivity indexes; determination of amount of soil sediment; sediment grain size characteristics; natural amounts of nutrients Ca, Mg, K and P, as well as total C and N concentrations. The results for the three first measurements were 52.5, 20.5, and 29.0 Mg in the sediments from the gully without intervention, and of 1.0, 1.7 and 1.8 Mg from the gully with physical interventions, indicating an average reduction of 95 %. The fully recovered gully produced no sediment during the period. The data of total nutrient loss from the three gullies under investigation showed reductions of 98 % for the recovering gully, and 99 % for the fully recovered one. As for the loss of nutrients, the data indicate a nutrient loss of 1,811 kg from for the non-treated gully. The use of physical and biological interventions made it possible to reduce overall nutrient loss by more than 96 %, over the entire rainy season, as compared to the non-treated gully. Results show that the methods used were effective in reducing soil and nutrient losses from gullies.
24
Baulch, Helen M., Jane A. Elliott, Marcos R. C. Cordeiro, Don N. Flaten, David A. Lobb e Henry F. Wilson. "Soil and water management: opportunities to mitigate nutrient losses to surface waters in the Northern Great Plains". Environmental Reviews 27, n.º 4 (dezembro de 2019): 447–77. http://dx.doi.org/10.1139/er-2018-0101.
Texto completo da fonteResumo:
The Northern Great Plains is a key region to global food production. It is also a region of water stress that includes poor water quality associated with high concentrations of nutrients. Agricultural nitrogen and phosphorus loads to surface waters need to be reduced, yet the unique characteristics of this environment create challenges. The biophysical reality of the Northern Great Plains is one where snowmelt is the major period of nutrient transport, and where nutrients are exported predominantly in dissolved form. This limits the efficacy of many beneficial management practices (BMPs) commonly used in other regions and necessitates place-based solutions. We discuss soil and water management BMPs through a regional lens—first understanding key aspects of hydrology and hydrochemistry affecting BMP efficacy, then discussing the merits of different BMPs for nutrient control. We recommend continued efforts to “keep water on the land” via wetlands and reservoirs. Adoption and expansion of reduced tillage and perennial forage may have contributed to current nutrient problems, but both practices have other environmental and agronomic benefits. The expansion of tile and surface drainage in the Northern Great Plains raises urgent questions about effects on nutrient export and options to mitigate drainage effects. Riparian vegetation is unlikely to significantly aid in nutrient retention, but when viewed against an alternative of extending cultivation and fertilization to the waters’ edge, the continued support of buffer strip management and refinement of best practices (e.g., harvesting vegetation) is merited. While the hydrology of the Northern Great Plains creates many challenges for mitigating nutrient losses, it also creates unique opportunities. For example, relocating winter bale-grazing to areas with low hydrologic connectivity should reduce loadings. Managing nutrient applications must be at the center of efforts to mitigate eutrophication. In this region, ensuring nutrients are not applied during hydrologically sensitive periods such as late autumn, on snow, or when soils are frozen will yield benefits. Working to ensure nutrient inputs are balanced with crop demands is crucial in all landscapes. Ultimately, a targeted approach to BMP implementation is required, and this must consider the agronomic and economic context but also the biophysical reality.
25
Shukla, S., B. J. Boman, R. C. Ebel, P. D. Roberts e E. A. Hanlon. "Reducing Unavoidable Nutrient Losses from Florida's Horticultural Crops". HortTechnology 20, n.º 1 (fevereiro de 2010): 52–66. http://dx.doi.org/10.21273/horttech.20.1.52.
Texto completo da fonteResumo:
Despite efforts to optimize water and nutrient inputs to Florida's vegetable and fruit crops, the sandy soils, shallow water table, and tropical climate of Florida result in nutrient leaching losses that are unavoidable. Water quantity and quality management strategies that can reduce these nutrient losses from Florida's horticultural crops were reviewed and research needs for quantifying their effectiveness were identified. The water quantity management strategies included water table management for irrigation, drainage management, detention of runoff and drainage, and summer flooding. In addition to the expected water quality benefits of these practices, potential effects on crop production and farm economics were also discussed. Watershed-scale adoption of stormwater harvesting has the potential to not only reduce the nutrient loadings but also become a source of additional income for landowners through water trading. The water quality practices included structural and managerial practices (e.g., vegetative filter strips and ditch cleaning). Key research needs for reducing the unavoidable nutrient discharges included the development of a crop-specific drainage management tool; quantification of farm and watershed-scale benefits of stormwater detention and its reuse with regards to nutrient loadings, water supply, crop production, and farm income; enhancement of hydraulic efficiency of detention areas; and effects of summer flooding and ditch maintenance and cleaning on nutrient discharges.
26
Scagel, Carolyn F., Guihong Bi, Leslie H. Fuchigami e Richard P. Regan. "Nutrient Uptake and Loss by Container-grown Deciduous and Evergreen Rhododendron Nursery Plants". HortScience 46, n.º 2 (fevereiro de 2011): 296–305. http://dx.doi.org/10.21273/hortsci.46.2.296.
Texto completo da fonteResumo:
The influence of nitrogen (N) fertilizer application on plant allocation, uptake, and demand for other essential nutrients was evaluated from May 2005 to Feb. 2006 in evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ) grown in containers filled with soilless substrate. Net nutrient uptake and losses were calculated using piecewise regression and uptake efficiency, root absorption capacity, aboveground demand, nutrient use efficiency, and uptake ratios between N and other nutrients (N ratios) were calculated using net uptake between harvest dates. Nitrogen application increased uptake rate of all nutrients, enhanced late-season uptake of many nutrients, and increased the rate of nutrient loss during the winter. Nutrient uptake often occurred as late as November in plants grown with N but was usually undetectable after September in plants grown without additional N fertilizer. Nutrient losses during the winter were not always associated with biomass loss and were related to differences in preferential nutrient allocation to different structures and the plant's ability to export nutrients before biomass loss. Plants with a greater potential for rapid growth were more capable of later-season nutrient uptake than plants with slower growth rates. Nitrogen availability altered N ratios indicating that when adding N to container-grown Rhododendron, fertilizers with higher ratios of N/phosphorus (PJM, AZ), N/calcium (PJM, ER), N/boron (PJM AZ), N/copper (PJM, ER), and N/iron (PJM, ER) and lower ratios of N/potassium (PJM, ER, AZ), N/sodium (PJM, ER, AZ), N/calcium (AZ), N/boron (ER), N/manganese (AZ), and N/zinc (ER) may be needed to optimize growth and minimize nutrient inputs. Increasing N availability altered uptake efficiency, root absorption capacity, aboveground demand, and nutrient use efficiency for several nutrients, indicating that changes in N management practices need to consider how altering N application rates may influence the plant's ability to take up and use other nutrients. This information can be used to develop fertilizer formulations to minimize excess application of nutrients and to evaluate the potential effects of altering N management practices on use of production resources. Our results indicate that nutrient management strategies for perennial crops such as Rhododendron need to take into consideration not only the nutrient demand for current growth, but also how to optimize nutrient availability for uptake that contributes to future growth potential and end-product quality.
27
Lu, Shuning, Chong Yao e Faqi Wu. "Effects of Counter Tillage and Slope Gradient on Nutrient Losses on Sloping Farmland". Sustainability 15, n.º 3 (20 de janeiro de 2023): 2019. http://dx.doi.org/10.3390/su15032019.
Texto completo da fonteResumo:
Counter tillage is a typical cultivation practice on the Loess Plateau, which can influence the soil erosion process by intercepting runoff and increasing infiltration. However, few studies have investigated the mechanisms of nutrient losses associated with counter tillage. This study was conducted to reveal the effects of counter tillage and slope gradient on the soil nutrient loss mechanism on sloping farmland. In this study, the rainfall simulation was conducted with a rainfall intensity of 90 mm.h−1 and with five slope gradients (5.24%, 8.75%, 17.63%, 26.79%, 36.40%). The runoff plots involved the counter tillage (CT) and traditional plow (CK), in order to investigate the characteristics of soil erosion and available phosphorus (AP), ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−- N) losses. The soil erosion characteristics included the time until runoff generation, RR (runoff rate), and SR (sediment rate); the nutrient loss characteristics included nutrient loss concentrations, nutrient loss and nutrient loss rate in runoff or sediment. The results indicated that the RR and SR with a slope gradient of 5.24~26.79% on CT decreased by 11.77~94.92% and 20.69~99.27%, respectively, compared with that of CK. As the slope gradient increased (36.40%), a break in the ridge occurred and the reduction in the RR and SR was weakened; this was likely to be close to that of the CK. Nutrient losses differed significantly between different slope gradients and tillage practices. Nutrient losses increased with an increasing slope gradient. The nutrient losses of AP, NH4+-N, and NO3−-N in runoff, with the slope gradient of 36.40%, increased 75.75%, 76.34%, 75.63%; meanwhile, in sediment, it increased 32.93, 30.70, 32.18 times, compared with the slope gradient of 5.24% on CT. The CT with the slope gradient of 5.24~26.79% had a good effect in controlling nutrient losses; however, for the slope gradient of 36.40%, the effects of CT in controlling nutrient losses decreased. The nutrient loss rate and RR or SR satisfied a linear positive correlation. The reduction benefits of nutrient losses on CT in runoff and sediment can reach 57.7% to 100% and 45.5% to 100%, respectively. In conclusion, CT is an effective tillage practice to control soil erosion and nutrient losses. This study can provide a reference for soil erosion and nutrient loss control on sloping farmland on the Loess Plateau.
28
Bechmann, Marianne E., e Frederik Bøe. "Soil Tillage and Crop Growth Effects on Surface and Subsurface Runoff, Loss of Soil, Phosphorus and Nitrogen in a Cold Climate". Land 10, n.º 1 (15 de janeiro de 2021): 77. http://dx.doi.org/10.3390/land10010077.
Texto completo da fonteResumo:
Most studies on the effects of tillage operations documented the effects of tillage on losses through surface runoff. On flat areas, the subsurface runoff is the dominating pathway for water, soil and nutrients. This study presents results from a five-year plot study on a flat area measuring surface and subsurface runoff losses. The treatments compared were (A) autumn ploughing with oats, (B) autumn ploughing with winter wheat and (C) spring ploughing with spring barley (n = 3). The results showed that subsurface runoff was the main source for soil (67%), total phosphorus (76%), dissolved reactive phosphorus (75%) and total nitrogen (89%) losses. Through the subsurface pathway, the lowest soil losses occurred from the spring ploughed plots. Losses of total phosphorus through subsurface runoff were also lower from spring ploughing compared to autumn ploughing. Total nitrogen losses were higher from autumn ploughing compared to other treatments. Losses of total nitrogen were more influenced by autumn ploughing than by a nitrogen surplus in production. Single extreme weather events, like the summer drought in 2018 and high precipitation in October 2014 were crucial to the annual soil and nutrient losses. Considering extreme weather events in agricultural management is a necessary prerequisite for successful mitigation of soil and nutrient losses in the future.
29
Coblinski, João Augusto, Nerilde Favaretto, Gabriel Democh Goularte, Jeferson Dieckow, Anibal de Moraes e Luiz Claudio de Paula Souza. "Water, Soil and Nutrients Losses by Runoff at Hillslope Scale in Agricultural and Pasture Production in Southern Brazil". Journal of Agricultural Science 11, n.º 6 (15 de maio de 2019): 160. http://dx.doi.org/10.5539/jas.v11n6p160.
Texto completo da fonteResumo:
Agricultural activity, if not well managed, is an important source of water pollution mainly by surface runoff. The aim of this study was to evaluate losses of water, soil and soluble nutrient (phosphorus, nitrogen and carbon) via runoff in large plots (hillslope from 3,000 to 11,000 m2) at slope of 4 to 5% in annual crops (corn and sunflower) and pasture systems under no-tillage and no-pesticides. The study was carried out at the Canguiri Experimental Farm of the Federal University of Paraná, Southern Brazil, in soil classified as Ferralsol in three systems (crop, pasture and crop-pasture). Soil physical and chemical attributes as well as topographic indices and soil cover were investigated to evaluate the possible impacts of these variables on losses. The runoff was measured after each rainfall event from November 2014 to October 2015. Runoff samples were taken to analyse sediment and nutrients. All systems had low water, soil and nutrients losses compared to no conservative agricultural systems. Higher losses occurred in the annual crops system and were influenced by soil cover, with an annual runoff coefficient of 0.62% (7 mm of water loss) and an annual soil loss of 2.6 kg ha-1. The seasonality (winter/summer) did not influence soil, water and nutrient losses.
30
Blomqvist, Anna. "How can stakeholder participation improve European watershed management: the Water Framework Directive, watercourse groups and Swedish contributions to Baltic Sea eutrophication". Water Policy 6, n.º 1 (1 de fevereiro de 2004): 39–52. http://dx.doi.org/10.2166/wp.2004.0003.
Texto completo da fonteResumo:
Nutrient losses from agricultural land constitute an important part of the total flow of nutrients to lakes and seas in Sweden and the Baltic region. With the Water Framework Directive, to be implemented shortly throughout Europe, emphasis is increasing on the role of stakeholder participation and decentralisation of various responsibilities from authorities to groups in the civil society. This paper investigates a Swedish case where local watercourse groups (WCGs) have formed in order to be involved more actively in the efforts to reduce nutrient losses from agricultural lands. This paper presents a qualitative analysis of the institutional landscape surrounding WCGs, goals, goal formulation and space of action.
31
Pomar, Candido, e Aline Remus. "242 The Impact of Feed Formulation and Feeding Methods on Pig and Poultry Production on the Environment". Journal of Animal Science 100, Supplement_3 (21 de setembro de 2022): 124. http://dx.doi.org/10.1093/jas/skac247.237.
Texto completo da fonteResumo:
Abstract Dietary energy and nutrient losses associated with its conversion into animal products increase production costs and contribute to the environmental footprint of farms with the excessive application of nitrogen, phosphorus, or trace minerals from manure or carbon and methane losses. Formulating diets with the appropriate levels of minerals and amino acids can help improve dietary protein and energy efficiency and reduce nutrient losses. For example, an 8% reduction in dietary crude protein in pig feeds is estimated to increase nitrogen efficiency by more than 50%, while costing 11% less than a control diet without industrial amino acids. This reduction in protein intake also increases energy availability due to reduced energy losses associated with protein deamination. Urinary and intestinal fermentation energy losses can be 24% lower for pigs fed low-protein diets compared to control diets. Nonetheless, determining the optimal level of dietary amino acid remains a difficult challenge in conventional phase feeding systems. Therefore, group or individual precision feeding is another powerful tool to increase nutrient efficiency. By feeding individual growing-finishing pigs with diets tailored to their requirements, precision feeding can decrease nitrogen excretion by 30% and greenhouse gas emissions by 22% compared to conventional 3-phase feeding. The benefits of feeding pigs with low-protein diets and precision feeding techniques are additive and might result in a 61% protein efficiency of utilization. The formulation of very-low-protein diets and the implementation of precision feeding techniques rely on sound nutritional concepts and comprehensive biological models developed to precisely estimate individual real-time nutrient requirements and animal responses. Understanding the metabolic processes responsible for the observed variation between individual animals in their ability to utilize dietary nutrients is challenging, but there is a need to further improve nutrient efficiency and reduce the environmental impact of livestock production systems.
32
Vagstad, N., P. Stålnacke, H. E. Andersen, J. Deelstra, V. Jansons, K. Kyllmar, E. Loigu, S. Rekolainen e R. Tumas. "Regional variations in diffuse nitrogen losses from agriculture in the Nordic and Baltic regions". Hydrology and Earth System Sciences 8, n.º 4 (31 de agosto de 2004): 651–62. http://dx.doi.org/10.5194/hess-8-651-2004.
Texto completo da fonteResumo:
Abstract. This paper describes nitrogen losses from, and the characteristics of, 35 selected catchments (12 to 2000 ha) in the Nordic and Baltic countries. Average annual losses of N in 1994–1997 ranged from 5 to 75 kg ha-1, generally highest and characterised by significant within-country and interannual variations, in Norway and the lowest losses were observed in the Baltic countries. An important finding of the study is that the average nutrient losses varied greatly among the studied catchments. The main explanations for this variability were water runoff, fertiliser use (especially the amount of manure), soil type and erosion (including stream bank erosion). However, there were several exceptions, and it was difficult to find general relationships between the individual factors. For example, there was poor correlation between nitrogen losses and surpluses. Therefore, the results suggest that the observed variability in N losses cannot have been due solely to differences in farm management practices, although the studied catchments do include a wide range of nutrient application levels, animal densities and other relevant elements. There is considerable spatial variation in the physical properties (soil, climate, hydrology, and topography) and the agricultural management of the basins, and the interaction between and relative effects of these factors has an important impact on erosion and nutrient losses. In particular, hydrological processes may have a marked effect on N losses measured in the catchment stream water. The results indicate that significant differences in hydrological pathways (e.g. the relationship between fast- and slow-flow processes) lead to major regional differences in N inputs to surface waters and therefore also in the response to changes in field management practices. Agricultural practices such as crop rotation systems, nutrient inputs and soil conservation measures obviously play a significant role in the site-specific effects, although they cannot explain the large regional differences observed in this study. The interactions between agricultural practices and basic catchment characteristics, including hydrological processes, determine the final losses of nitrogen to surface waters, hence it is necessary to understand these interactions to manage diffuse losses of agricultural nutrients efficiently. Keywords: agriculture, catchments, diffuse sources, nitrogen, losses, Baltic, Nordic
33
Behrendt, Horst. "Inventories of point and diffuse sources and estimated nutrient loads - a comparison for different river basins in Central Europe". Water Science and Technology 33, n.º 4-5 (1 de fevereiro de 1996): 99–107. http://dx.doi.org/10.2166/wst.1996.0493.
Texto completo da fonteResumo:
A comparison of the estimated emissions (input) with the measured loads at monitoring stations (output) is presented for the large Rivers Rhine, Elbe and its main tributaries and for the River Warnow, a smaller river in the north-east part of Germany. The comparison shows that the discrepancies between the estimated emissions and the measured load is small for the Rhine and its main tributaries, Mosel, Neckar and Main. Large discrepancies were found for the Elbe and its main tributaries. For all investigated river systems a strong relationship exists between the quotient of measured nutrient load versus the estimated sum of point and diffuse emissions of nutrients and the areal specific runoff. A function is derived for the dependency of the sum of retention and/or losses in a river system on the specific runoff and the nutrient concentration in the river. The high accuracy of the estimated retention and/or losses within the different river basins offer the possibility to use these equations for a prediction of the emitted nutrients from measured nutrient load in similar rivers.
34
Kellman, Martin. "Nutrient retention by tropical ecosystems: soil adsorption and plant absorption as synergistic processes". Journal of Tropical Ecology 18, n.º 6 (25 de setembro de 2002): 877–95. http://dx.doi.org/10.1017/s0266467402002572.
Texto completo da fonteResumo:
Laboratory and growth-chamber experiments were used to evaluate whether there was evidence for nutrient retention by tropical terrestrial ecosystems being a two-stage process involving first soil adsorption and then plant absorption. Quartz sand with and without Fe and Al oxide coatings were treated with nutrient solution, then subjected to a leaching regime that simulated early wet-season conditions at a tropical location. Nutrient cations applied were rapidly lost in the initial leaches from quartz sand without oxide coatings, but showed a more gradual loss from oxide-coated sand, indicating temporary adsorption by the latter. In a second experiment, oxide-coated sand with and without seedlings of Grevillea robusta (a non-mycorrhizal tree species) were subjected to a similar treatment and leaching losses were compared. The presence of seedlings significantly reduced the losses of all nutrient cations, with the effect being minimal for Na and greatest for K, confirming that plants can gain access to temporarily adsorbed nutrients. More typical tropical soil-vegetation systems are likely to possess properties that magnify both the adsorptive and absorptive processes that have been documented in these experiments, justifying extrapolation of the experimental results to these natural systems. The existence of a two-stage process of nutrient retention provides a plausible explanation for the resistance of most tropical ecosystems to rapid loss of nutrients following events such as fires, which provide acute nutrient loading to the system.
35
Kurz, I., H. Tunney e C. E. Coxon. "The impact of agricultural management practices on nutrient losses to water: data on the effects of soil drainage characteristics". Water Science and Technology 51, n.º 3-4 (1 de fevereiro de 2005): 73–81. http://dx.doi.org/10.2166/wst.2005.0577.
Texto completo da fonteResumo:
Against the background of increasing nutrient concentrations in Irish water bodies, this study set out to gain information on the potential of agricultural grassland to lose nutrients to water. Overland flow, flow from artificial subsurface drains and stream flow were gauged and sampled during heavy rainfall events. Dissolved reactive phosphorus (DRP), potassium (K), total ammonia (TA), and total oxidised nitrogen (TON) were measured in water samples. When the nutrient concentrations in water were examined in relation to the grassland management practices of the study catchments it emerged that soil P levels, the application of organic and inorganic fertilisers before heavy rainfall and the presence of grazing animals could all influence nutrient concentrations in surface and subsurface drainage water. Overall, the drainage characteristics of soil were found to have a considerable influence on the potential of land to lose nutrients to water.
36
Marley, C. L., R. Fychan, M. D. Fraser, R. Sanderson e R. Jones. "The effect of feeding ensiled alternative forages compared with ensiled ryegrass on excreta losses from growing lambs". Proceedings of the British Society of Animal Science 2009 (abril de 2009): 162. http://dx.doi.org/10.1017/s1752756200030015.
Texto completo da fonteResumo:
An experiment investigated the effects of using ensiled alternative forages compared with ensiled ryegrass on lamb productivity, nutrient use efficiency and total excreta losses in a lamb finishing system. Lambs offered alternative forages had a higher liveweight gain and nitrogen use efficiency than lambs offered ryegrass silage (P < 0.001) (Marley et al., 2007). However, balancing the input and output of nutrients within the farm system is critical to ensure both short-term productivity and long-term sustainability, as producers aim to establish whole-farm nutrient balance plans and reduce reliance on bought-in fertilisers. Here we present the findings of the effects of feeding ensiled red clover (Trifolium pratense), lucerne (Medicago sativa), pea (Pisum sativum), kale (Brassica oleracea) compared with ensiled hybrid ryegrass (Lolium hybridicum) on excreta losses from these growing lambs and, therefore, the potential impact of incorporating these forages on nutrient budgets within livestock systems.
37
Smith, D. R., S. J. Livingston, B. W. Zuercher, M. Larose, G. C. Heathman e C. Huang. "Nutrient losses from row crop agriculture in Indiana". Journal of Soil and Water Conservation 63, n.º 6 (1 de novembro de 2008): 396–409. http://dx.doi.org/10.2489/jswc.63.6.396.
Texto completo da fonte
38
Fillion, L., e C. J. K. Henry. "Nutrient losses and gains during frying: a review". International Journal of Food Sciences and Nutrition 49, n.º 2 (janeiro de 1998): 157–68. http://dx.doi.org/10.3109/09637489809089395.
Texto completo da fonte
39
Kuusemets, Valdo, e Ülo Mander. "Ecotechnological Measures to Control Nutrient Losses from Catchments". Water Science and Technology 40, n.º 10 (1 de novembro de 1999): 195–202. http://dx.doi.org/10.2166/wst.1999.0520.
Texto completo da fonteResumo:
Ecotechnological measures allow to use different natural and seminatural ecosystems to control nutrient losses from intensively used watersheds. The most effective means are buffer strips, buffer zones and constructed wetlands. In southern Estonia a 31 m wide buffer zone of wet meadow and grey alder forest removed 50% nitrogen and 78% phosphorus, while in a 51 m buffer zone, also containing a grassland strip in addition to wet meadow and alder forest, 87 % N and 84 % P was retained. The outflow of total – N was 4.9% and outflow of total – P was 4.8% lower in well-buffered watershed in comparison to similar watershed with lower buffering ability. Three constructed wetlands in southern Estonia were studied. The removal efficiency was 76 – 84% for BOD5, 39 – 70% for total-N, 73 – 83% for total-P. All results show that compared to other seasons the winter performance was not reduced.
40
Shirmohammadi, A., F. Djodjic e L. Bergström. "Scaling issues in sustainable management of nutrient losses". Soil Use and Management 21, n.º 1 (28 de junho de 2008): 160–66. http://dx.doi.org/10.1111/j.1475-2743.2005.tb00120.x.
Texto completo da fonte
41
Shirmohammadi, A., F. Djodjic e L. Bergstrom. "Scaling issues in sustainable management of nutrient losses". Soil Use and Management 21, s1 (março de 2005): 160–66. http://dx.doi.org/10.1111/j.1475-2743.2005.tb00420.x.
Texto completo da fonte
42
Shirmohammadi, A., F. Djodjic e L. Bergström. "Scaling issues in sustainable management of nutrient losses". Soil Use and Management 21, n.º 1 (1 de março de 2005): 160–66. http://dx.doi.org/10.1079/sum2005302.
Texto completo da fonte
43
Andiru, G. A., C. C. Pasian e J. M. Frantz. "Quantifying Water and Nutrient Losses with Hose Irrigation". Journal of Environmental Horticulture 33, n.º 1 (1 de março de 2015): 29–32. http://dx.doi.org/10.24266/0738-2898-33.1.29.
Texto completo da fonteResumo:
The amount of water, nitrogen (N), phosphorous (P), and iron (Fe) lost from potted impatiens (Impatiens wallerana Hook. f.) plants fertilized with either controlled-release fertilizer (CRF) of varying longevities or a water-soluble fertilizer (WSF), with irrigation provided with a hose in all treatments, was quantified. The plants were grown in a sphagnum peat-based soilless substrate containing either CRF [Osmocote Plus 16-9-12 (16-3.9-10-0.46 N:P:K:Fe), 5 to 6 month and or 8-to 9 month longevities] incorporated (6.8 kg·m−3 or 11.5 lb·yd−3) throughout the substrate and compared with plants fertigated with a WSF [Peters Professional 20-10-20 (20-4.4-1.66-0.1 N:P:K:Fe) at 150 mg·L−1 (150 ppm) N]. The container-grown plants were placed on top of plastic cups and located inside a plastic box. Municipal water or mineral nutrient solution leached from each container and lost between containers was captured, quantified and analyzed for N, P, and Fe concentrations. As an average for the three treatments, 25.6% of the total water applied was leached out of the pots and 34% fell between the pots. Six weeks after starting the experiment, leachate from pots fertilized with WSF had approximately a 92% higher concentration of N, 96% more P, and 69% more Fe than the concentrations in leachate from CRF-fertilized pots. These results quantify the assumed inefficiencies of using a hose as the primary fertilizer delivery method.
44
Andreu, V., JL Rubio, J. Forteza e R. Cerni. "Postfire Effects on Soil Properties and Nutrient Losses". International Journal of Wildland Fire 6, n.º 2 (1996): 53. http://dx.doi.org/10.1071/wf9960053.
Texto completo da fonteResumo:
The effects of an August, 1992, wildfire on nutrient losses by water erosion have been studied. The fire affected an area of 9498 ha of pine forest and shrub, located in Sierra Calderona (Valencia, Spain). In the burned area, six stations of erosion measurement were set up immediately after the end of the fire. The results obtained in these stations are reported. Topographical, edaphological and vegetation characteristics of each station are described. Fourteen episodes of erosive rain with production of runoff and sediments, between August,1992, and November, 1993, were studied, mainly in relation to changes in the soil chemical characteristics. Data show that the highest soil and nutrient losses were produced in the period immediately after the fire. However, fire intensity is the factor that determines the soil status with respect to its response to nutrient losses.
45
Lagzdiņš, Ainis, Viesturs Jansons, Ritvars Sudars, Linda Grinberga, Arturs Veinbergs e Kaspars Abramenko. "Nutrient losses from subsurface drainage systems in Latvia". Acta Agriculturae Scandinavica, Section B — Soil & Plant Science 65, sup1 (27 de março de 2015): 66–79. http://dx.doi.org/10.1080/09064710.2014.983962.
Texto completo da fonte
46
Safley, L. M., P. W. Westerman e J. C. Barker. "Fresh dairy manure characteristics and barnlot nutrient losses". Agricultural Wastes 17, n.º 3 (janeiro de 1986): 203–15. http://dx.doi.org/10.1016/0141-4607(86)90094-6.
Texto completo da fonte
47
Liu, J. X., D. Q. Zhang, G. Y. Zhou, B. Faivre-Vuillin, Q. Deng e C. L. Wang. "CO<sub>2</sub> enrichment increases nutrient leaching from model forest ecosystems in subtropical China". Biogeosciences Discussions 5, n.º 3 (27 de junho de 2008): 2679–706. http://dx.doi.org/10.5194/bgd-5-2679-2008.
Texto completo da fonteResumo:
Abstract. The effect of high atmospheric CO2 concentrations on the dynamics of mineral nutrient is not well documented, especially for subtropical China. We used model forest ecosystems in open-top chambers to study the effects of CO2 enrichment alone and together with N addition on the dynamics of soil cations and anions. Two years of exposure to a 700 ppm CO2 atmospheric concentration resulted in increased annual nutrient losses by leaching below 70 cm soil profile. Compared to the control, net Mg2+ losses increased by 385%, K+ by 223%, Ca2+ by 167% and N-NO3- by 108%, respectively. Increased losses following exposure to elevated CO2 were related to both faster soil weathering/organic matter decomposition and greater amounts of water leaching during high rainfall as a consequence of higher soil moisture. Net annual nutrient losses in the high CO2 concentration chambers reached 22.2 kg ha−1 year−1 for K+, 171.3 kg ha−1 year−1 for Ca2+, 8.2 kg ha−1 year−1 for Mg2+ and about 2 kg ha−1 year−1 for N-NO3-. The N addition alone had no significant effect on the mineral nutrient leaching losses. However, addition of N together with the high CO2 treatment significantly reduced mineral nutrient losses. We hypothesize that forests in subtropical China might suffer nutrient limitation and reduction in plant biomass under elevated CO2 concentration due to mineral leaching losses in the future.
48
Courtois, F., L. Vedrenne e S. Georgé. "Mathematical Modelling of Some Nutrient Losses during Heat Treatment of Stewed Apples". Czech Journal of Food Sciences 27, Special Issue 1 (24 de junho de 2009): S23—S26. http://dx.doi.org/10.17221/966-cjfs.
Texto completo da fonteResumo:
Vitamin C (later noted VITC) and polyphenols (later noted PP) were regarded as main nutritional markers in the transformation process of stewed apples after an <I>in situ</I> measurement campaign at two leading French industrials on that matter. Experiments on pilots with the CTCPA of Avignon made it possible to create a small experimental data base whose treatment is the core of this article. The objective of this work is to check if the experimental data collected at the CTCPA facility can be represented by a single model of 2 separate first order reactions, with or without Arrhenius, under varying processing temperatures.
49
Liu, J. X., D. Q. Zhang, G. Y. Zhou, B. Faivre-Vuillin, Q. Deng e C. L. Wang. "CO<sub>2</sub> enrichment increases nutrient leaching from model forest ecosystems in subtropical China". Biogeosciences 5, n.º 6 (23 de dezembro de 2008): 1783–95. http://dx.doi.org/10.5194/bg-5-1783-2008.
Texto completo da fonteResumo:
Abstract. The effect of high atmospheric CO2 concentrations on the dynamics of mineral nutrient is not well documented, especially for subtropical China. We used model forest ecosystems in open-top chambers to study the effects of CO2 enrichment alone and together with N addition on the dynamics of soil cations and anions. Two years of exposure to a 700 ppm CO2 atmospheric concentration resulted in increased annual nutrient losses by leaching below 70 cm soil profile. Compared to the control, net Mg2+ losses increased by 385%, K+ by 223%, Ca2+ by 167% and NO3−-N by 108%, respectively. Increased losses following exposure to elevated CO2 were related to both faster weathering of minerals/organic matter decomposition and greater amounts of leaching water. Net annual nutrient losses in the high CO2 concentration chambers reached 22.2 kg ha−1 year−1 for K+, 171.3 kg ha−1 year−1 for Ca2+, 8.2 kg ha−1 year−1 for Mg2+ and about 2 kg ha−1 year−1 for NO3−-N. The N addition alone had no significant effect on the mineral nutrient leaching losses. However, addition of N together with the high CO2 treatment significantly reduced mineral nutrient losses.We hypothesize that forests in subtropical China might suffer from nutrient limitation and reduction in plant biomass under elevated CO2 concentration due to mineral leaching losses in the future.
50
Zhao, Zhanqing, Zhaohai Bai, Sha Wei, Wenqi Ma, Mengru Wang, Carolien Kroeze e Lin Ma. "Modeling farm nutrient flows in the North China Plain to reduce nutrient losses". Nutrient Cycling in Agroecosystems 108, n.º 2 (12 de maio de 2017): 231–44. http://dx.doi.org/10.1007/s10705-017-9856-8.
Texto completo da fonte