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1
Ma, Xi Xi, e Jian Jun Yuan. "Study on the Leaching of Sodium Nitrate from Nitratine". Advanced Materials Research 236-238 (maggio 2011): 2539–43. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.2539.
Testo completoAbstract (sommario):
The technology on the leaching process of sodium nitrate from nitratine was developed in this work. The effects of leaching duration, solid-to-liquid ratio on the leaching were studied. The results show that the utilizable sodium nitrate leaching ratio from the nitratine reach 90.2%, for leaching duration of 15 minute and at the solid-to-liquid ratio of 1.0 g.g-1. A new scheme of step-by-step spray is advanced, according to the result of leaching repeatedly, which increased the concentration of lixiviation up to 29.58%( 400g.L-1) at 25°C. The results reported will be useful for leaching process design and control.
2
Castellón, César I., Pía C. Hernández, Lilian Velásquez-Yévenes e María E. Taboada. "An Alternative Process for Leaching Chalcopyrite Concentrate in Nitrate-Acid-Seawater Media with Oxidant Recovery". Metals 10, n. 4 (17 aprile 2020): 518. http://dx.doi.org/10.3390/met10040518.
Testo completoAbstract (sommario):
An alternative copper concentrate leaching process using sodium nitrate and sulfuric acid diluted in seawater followed by gas scrubbing to recover the sodium nitrate has been evaluated. The work involved leaching test carried out under various condition by varying temperature, leaching time, particle size, and concentrations of NaNO3 and H2SO4. The amount of copper extracted from the chalcopyrite concentrate leached with seawater, 0.5 M of H2SO4 and 0.5 M of NaNO3 increased from 78% at room temperature to 91% at 45 °C in 96 h and 46 h of leaching, respectively. Gas scrubbing with the alkaline solution of NaOH was explored to recover part of the sodium nitrate. The dissolved salts were recovered by evaporation as sodium nitrate and sodium nitrite crystals.
3
Ji, Shu Hua, e Jiang Yang Deng. "Numerical Simulation on Characteristics of Nitrate Nitrogen Leaching under Different Irrigation Levels". Applied Mechanics and Materials 662 (ottobre 2014): 153–59. http://dx.doi.org/10.4028/www.scientific.net/amm.662.153.
Testo completoAbstract (sommario):
The characteristics of nitrate nitrogen leaching in soil under different irrigation levels were studied by soil column simulation experiment with numerical simulation done using LEACHM model taking nitrate nitrogen leaching under different irrigation levels as the research background. In sandy soils, an irrigation amount of 300 mm would cause nitrate nitrogen to leach downward 75~150 cm, with a leaching amount of 10~30.7 kg/ha; and an irrigation amount of 700 mm would make nitrate nitrogen leach downward about 3.5 m, with a leaching amount of 98 kg/ha. Research data showed that the amount of nitrate nitrogen leaching was positively correlated with the irrigation intensity level, irrigation level directly determined the amount of nitrate nitrogen leaching, and influenced its leaching depth.
4
Aoun, Omar, Salem Benamara, Farid Dahmoune, Hocine Remini, Sofiane Dairi, Amine Belbahi, Brahim Bousalhih e Khodir Madani. "Modeling of nitrate leaching kinetics during Spinach Leaf Midribs blanching". North African Journal of Food and Nutrition Research 2, n. 4 (23 novembre 2018): 112–20. http://dx.doi.org/10.51745/najfnr.2.4.112-120.
Testo completoAbstract (sommario):
Background: Although nitrates, are sometimes favorable to health, they can however convert to nitrosamines inside the body thanks to the acidic medium of gastrointestinal tract. So, the investigation of the nitrate content in food products becomes an imperative since it allows consumers to choose their food deliberately. Aims: The leaching kinetics of nitrates during water blanching of spinach leaf midribs (SLM) was investigated at different conditions of time and temperature. Methods and Material: The nitrate leaching kinetics, during the water blanching of SLM samples, was studied at 60, 70 and 80 ° C; for 3 and 15 minutes. Presently, six models, namely Henderson and Pabis, logarithmic, zero order, Lewis, Page, Wang, and Singh were tested to analyze experimental data. Moreover, to elucidate the effect of the temperature on the nitrate diffusion rate, the equation of Arrhenius was applied. Results: Results showed that after 15 min of blanching, the removal rate (RR) of nitrates was of: 23.851±3.477c, 64.809±0.474b and 75.949±5.366a % at 60, 70 and 80 °C, respectively; with a significant difference between values at (p≤0.05). Furthermore, among the six tested models, the logarithmic model seemed to be the most appropriate (R2>0.993) to describe the diffusion kinetics of nitrates from food matrix into the blanching water, whatever the processing temperature. Finally, the activation energy (35.76 kJ. Mol-1), characterizing the nitrate leaching, was assessed based on the rate constant appearing in the most appropriate model. Conclusions: Blanching in water constitutes an effective tool for controlling the nitrate content in vegetables, by varying the time and temperature of treatment. Keywords: Nitrate, quantification, spinach leaf midribs, blanching, modeling.
5
Pote, John W., Chhandak Basu, Zhongchun Jiang e W. Michael Sullivan. "Relationship between Nitrate Leaching under Turf and Nitrate Uptake by Turfgrasses". HortScience 35, n. 5 (agosto 2000): 827B—827. http://dx.doi.org/10.21273/hortsci.35.5.827b.
Testo completoAbstract (sommario):
Leaching-induced N losses have been shown to be minimal under turfgrasses. This is likely due to superior ability of turfgrasses to absorb nitrate. No direct evidence for this theory has been reported. The present study quantified nitrate leaching under miniature turf and nitrate uptake by individual turfgrass plants, and established the relationship between nitrate leaching loss and nitrate uptake rate. Seedlings of six Kentucky bluegrass (Poa pratensis L.) cultivars, `Blacksburg', `Barzan', `Connie', `Dawn', `Eclipse', and `Gnome', were planted individually in polystyrene containers filled with silica sand. The plants were irrigated with tap water or a nutrient solution containing 1 mm nitrate on alternate days and mowed to a 5-cm height once each week for 25 weeks. Nitrate leaching potential was then determined by applying 15 to 52 mL of nutrient solutions containing 7 to 70 mg·L-1 nitrate-N into the containers and collecting leachate. After the leaching experiment, plants were excavated, roots were washed to remove sand, and the plants were grown individually in containers filled with 125 mL of a nutrient solution containing 8.4 mg·L-1 nitrate-N. Nitrate uptake rate was determined by monitoring nitrate depletion at 24-hour intervals. Leachate nitrate-N concentration ranged from 0.5 to 6 mg·L-1 depending on cultivar, initial nitrate-N concentration, irrigation volume, and timing of nitrate-N application. Significant intraspecific difference in nitrate uptake rate on a root length basis was observed. Nitrate uptake rate on a per plant basis was significantly (P ≤ 0.05) and negatively correlated (r = -0.65) with nitrate leaching loss. The results provide strong evidence that superior nitrate uptake ability of turfgrass roots could reduce leaching-induced nitrate-N losses.
6
Kaluli, J. W., C. A. Madramootoo e Y. Djebbar. "Modeling nitrate leaching using neural networks". Water Science and Technology 38, n. 7 (1 ottobre 1998): 127–34. http://dx.doi.org/10.2166/wst.1998.0285.
Testo completoAbstract (sommario):
Accurate evaluation of nitrate leaching potential in agricultural fields is a major challenge. Field data are expensive to gather and use of existing prediction models is limited by inadequate understanding of the physical and chemical processes underlying nitrate leaching. A neural network model was developed to acquire the inherent characteristics of an experimental data set, and successfully used to simulate nitrate leaching in agricultural drainage effluent under various management systems. Simulation results indicated that: (i) sub-irrigation with a 0.5 m water table depth could reduce nitrate leaching to negligible levels, (ii) intercropping corn with ryegrass could reduce nitrate leaching by 50%, and (iii) the application of more than 180 kg N ha−1 of fertilizer may cause excessive nitrate leaching.
7
Defterdarović, Jasmina, Lana Filipović, Filip Kranjčec, Gabrijel Ondrašek, Diana Kikić, Alen Novosel, Ivan Mustać et al. "Determination of Soil Hydraulic Parameters and Evaluation of Water Dynamics and Nitrate Leaching in the Unsaturated Layered Zone: A Modeling Case Study in Central Croatia". Sustainability 13, n. 12 (12 giugno 2021): 6688. http://dx.doi.org/10.3390/su13126688.
Testo completoAbstract (sommario):
Nitrate leaching through soil layers to groundwater may cause significant degradation of natural resources. The aims of this study were: (i) to estimate soil hydraulic properties (SHPs) of the similar soil type with same management on various locations; (ii) to determine annual water dynamics; and (iii) to estimate the impact of subsoil horizon properties on nitrate leaching. The final goal was to compare the influence of different SHPs and layering on water dynamics and nitrate leaching. The study was conducted in central Croatia (Zagreb), at four locations on Calcaric Phaeozem, Calcaric Regosol, and Calcaric Fluvic Phaeozem soil types. Soil hydraulic parameters were estimated using the HYPROP system and HYPROP-FIT software. Water dynamics and nitrate leaching were evaluated using HYDRUS 2D/3D during a period of 365 days. The amount of water in the soil under saturated conditions varied from 0.422 to 0.535 cm3 cm–3 while the hydraulic conductivity varied from 3 cm day−1 to 990.9 cm day−1. Even though all locations have the same land use and climatic conditions with similar physical properties, hydraulic parameters varied substantially. The amount and velocity of transported nitrate (HYDRUS 2D/3D) were affected by reduced hydraulic conductivity of the subsoil as nitrates are primarily transported via advective flux. Despite the large differences in SHPs of the topsoil layers, the deeper soil layers, having similar SHPs, imposed a buffering effect preventing faster nitrate downward transport. This contributed to a very similar distribution of nitrates through the soil profile at the end of simulation period. This case study indicated the importance of carefully selecting relevant parameters in multilayered soil systems when evaluating groundwater pollution risk.
8
White, R. E., L. K. Heng e G. N. Magesan. "Nitrate leaching from a drained, sheep-grazed pasture. II. Modelling nitrate leaching losses". Soil Research 36, n. 6 (1998): 963. http://dx.doi.org/10.1071/s98012.
Testo completoAbstract (sommario):
Nitrate (NO-3 ) concentrations in 0·5-mm increments of drainage from adjacent mole- and pipe-drained paddocks of a silt loam soil under pasture near Palmerston North, New Zealand, were measured during 2 winters. The data were simulated using a simple analytical transfer function model (TFM). Urea fertiliser applied at the rate of 120 kg N/ha to one paddock was treated as a pulse input to the pool of resident soil NO-3. A source{sink term was included for plant uptake and net mineralisation (including any effect of denitrification). During the first winter (1990), a TFM using either a 1-parameter Burns probability density function (pdf) for solute travel, or a 2-parameter lognormal pdf, satisfactorily simulated the NO-3 concentration trends and predicted the total amounts of N leached. The pdf parameters were derived from previous chloride leaching data for this site. The best-fit value for the transport volume θst, the key parameter in the Burns pdf, was set at 0·37 m3 /m3 in 1990, as used in previous modelling of sulfate leaching. However, a value of 0 ·25 m3 /m3 in the Burns pdf gave better simulations of the 1991 data. This was probably due to more intense rain events during the early part of the drainage season in 1991 compared with 1990, which resulted in more preferential flow through the soil and a lower value for θst. The simulations for both years showed that ≥50% of the total leachable NO-3 was retained in the soil, despite normal winter drainage of about 300 mm. Ideally, the appropriate value of st should be determined by independent measurement. It may need to be adjusted according to the likely incidence of preferential flow early in the winter when NO-3 concentrations are highest. Provided the average initial soil NO-3 concentration can be estimated and a net source{sink term defined, the amount of NO-3 leached in drained soils can be satisfactorily modelled using the TFM approach with a 1-parameter pdf. Duplex soils which have a fluctuating watertable in the A horizon over an impermeable B horizon may prove to be an analogous system.
9
Sukreeyapongse, O., S. Panichsakpatana e J. Thongmarg. "Nitrogen leaching from soil treated with sludge". Water Science and Technology 44, n. 7 (1 ottobre 2001): 145–50. http://dx.doi.org/10.2166/wst.2001.0410.
Testo completoAbstract (sommario):
The amount of sludge generated from urban centers is increasing more and more, so wastewater treatment plants are being constructed. Recycling of sludge by application to agricultural land can alleviate the disposal pressure, and, at the same time, utilize the plant nutrients in the waste. Organic nitrogen in sludge is mineralized to inorganic forms such as nitrate and ammonium that can be taken up by plants. The inorganic forms of nitrogen, especially nitrates, can easily be leached because of its negative charge. Not only do nitrates cause eutrophication, but, at high concentration in drinking water, can also cause chemical suffocation disease in babies. This work is meant to quantify nitrate and ammonium nitrogen leached from soil treated with sludge. In order to obtain information on the composition of leachate from sludge, Kandiustults and a lysimeter study were used. Municipal and industrial sludge were applied to completely random design plots at different rates: 125, 250 and 375 kg N/ha. Each control lysimeter was treated with chemical fertilizer (N-P2O5-K2O : 20-10-10) at the rate of 125 kg N/ha. After the Chinese kale (Brassica oleracea L.) was planted in each lysimeter, leachate was collected every week and analyzed for NO3− and NH4+. The experiment was conducted at Kasetsart University, Bangkhen Campus, Bangkok, Thailand. Average nitrogen leach in the form of NO3− was 25 times more concentrated than the NH4+. Nitrate concentrations in the leachate exceeded the drinking water standard. Nitrate and ammonium leaching were measured to be between 1.50-3.00 % and 0.03-0.14% of the total treated nitrogen, respectively. Total nitrogen losses found in this study were 44.88%, 77.24% and 77.91% of the total nitrogen applied by chemical fertilizer, Huay Kwang sludge and Bangpa In sludge, respectively.
10
Adelman, D. D., e M. A. Tabidian. "The potential impact of soil carbon content on ground water nitrate contamination". Water Science and Technology 33, n. 4-5 (1 febbraio 1996): 227–32. http://dx.doi.org/10.2166/wst.1996.0509.
Testo completoAbstract (sommario):
A potential buildup of nitrate in the ground water resources of the eastern Sandhills of Nebraska has been projected to occur due to the intensive use of nitrogen fertilizer on irrigated cropland. A root-zone nitrate leaching study in this area revealed that soils with a high carbon concentration had minimal leaching compared to soils with lower concentrations. Soils high in carbon have an active population of denitrifying bacteria possibly causing denitrification and in turn reduction of nitrate leaching. Denitrifying bacteria are principally heterotrophic using soil organic carbon for both an energy and carbon source. The objective of this research was to interpret how root-zone denitrification affected nitrate leaching and ground water contamination by nitrate. A modified version of a solute transport model developed for the Eastern Sandhills was used to assess the risk of nitrate contamination for combinations of fertilizer and irrigation rates and for various soil carbon levels. The first attempt was to make risk assessment with eight farm management practices for cells with increasingly greater carbon levels until only those cells with the greatest carbon level were kept in production. Results of this assessment showed that even with excessive fertilizer and irrigation rates, risk of nitrate leaching was reduced as the minimum carbon level was increased. However, since less cropland was leaching nitrate with each successive risk calculation, the impact that root-zone denitrification had in nitrate leaching reduction could not be definitively determined. This prompted a model modification of the risk calculation procedure which kept all cropland in production and computed nitrate leachate risk for increasingly higher artificial carbon levels during successive risk calculations. Changing carbon levels was still more detrimental on nitrate leaching rates than changing farm management practices.
11
Vogeler, Iris, Adeline Blard e Nanthi Bolan. "Modelling DCD effect on nitrate leaching under controlled conditions". Soil Research 45, n. 4 (2007): 310. http://dx.doi.org/10.1071/sr06177.
Testo completoAbstract (sommario):
Effects of nitrogen losses through nitrate leaching are one of the major environmental issues worldwide. To determine the potential effect of dicyandiamide (DCD), a nitrification inhibitor, on the transformation of urea nitrogen and subsequent nitrate leaching, incubation and column leaching experiments were performed. Tokomaru silt loam soil was treated with urea, DCD, or urea plus DCD. A control was also used. In the laboratory incubation experiment, the conversion of urea to ammonium (i.e. ammonification process or urea hydrolysis) occurred within a day, thereby increasing the soil pH from 5.8 to 6.9. DCD did not affect the ammonification process. However, DCD did slow down the subsequent oxidation of ammonium to nitrate (i.e. nitrification process). The half-life time of ammonium in this soil was increased from 9 days for the urea treatment to 31 days for the urea + DCD treatment. The production of nitrate was 5 times slower when DCD was added. In the leaching experiments, half the columns were leached after 1 day of incubation (Day 1), the other half 7 days later (Day 7). For Day 1, no significant differences in nitrate leaching could be seen between the treatments, as the nitrification had not yet taken place. For Day 7, DCD decreased nitrate leaching by 71% with a corresponding decrease in nitrate-induced cation leaching, including ammonium. Thus, DCD seems to be effective in decreasing both ammonium and nitrate leaching, but its high solubility and thus mobility could be a limitation to its use. The convection–dispersion equation, including source–sink terms for nitrogen transformations, ammonification, and nitrification rate constants, and a factor for nitrification inhibition by DCD, accounting for degradation and efficiency of DCD, could be used reasonably well to simulate nitrate leaching from the column leaching experiments. However, model parameter values for nitrification rate, and efficiency and decay rate for DCD, were different from those obtained from the incubation experiments, which was probably because of the difference in water content of soil between the incubation and leaching experiments.
12
Ritter, W. F., R. W. Scarborough e A. E. M. Chirnside. "Nitrate Leaching under Irrigated Corn". Journal of Irrigation and Drainage Engineering 119, n. 3 (maggio 1993): 544–53. http://dx.doi.org/10.1061/(asce)0733-9437(1993)119:3(544).
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Shepherd, M. A. "Poultry manure and nitrate leaching". World's Poultry Science Journal 49, n. 2 (luglio 1993): 171–72. http://dx.doi.org/10.1079/wps19930015.
Testo completo
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Shepherd, M. A., D. J. Hatch, S. C. Jarvis e A. Bhogal. "Nitrate leaching from reseeded pasture". Soil Use and Management 17, n. 2 (19 gennaio 2006): 97–105. http://dx.doi.org/10.1111/j.1475-2743.2001.tb00014.x.
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van Bochove, E., M. M. Savard, G. Thériault, R. Cherif, N. Ziadi e J. MacLeod. "Nitrogen fertilizer impact on the Wilmot watershed aquifer in Prince Edward Island, Canada". Water Science and Technology 56, n. 1 (1 luglio 2007): 243–51. http://dx.doi.org/10.2166/wst.2007.458.
Testo completoAbstract (sommario):
The objective of this study is to estimate the soil N flux from the vadose zone to the aquifer of the Wilmot watershed (Prince Edward Island, Canada) for a typical three-year cropping rotation (barley–red clover–potato). A conceptual model estimates that 199–221 tons of N were yearly available for leaching at the watershed scale. A significant portion of this N amount was available for leaching at the end of the crop season representing 80–90% of the annual N balance. Drainage water nitrate concentrations were significantly higher after the potato-rotation year than during the crop season. Low nitrate concentrations were measured at spring thaw indicating that most of the nitrate available from the preceding potato crop season was likely leached at the end of fall or during winter. Early spring ionic exchange membrane sampling show a large availability of nitrate in soil possibly throughout winter as well, resulting from soil N mineralization and nitrification over the winter period. These findings are corroborated by the isotope natural abundance analysis of nitrate in groundwater implying that nitrifiers are significantly active during winter, as well as during the crop season, and that leaching of soil nitrates with seasonal signals takes place whenever recharge is occurring.
16
KOWALENKO, C. G. "THE DYNAMICS OF INORGANIC NITROGEN IN A FRASER VALLEY SOIL WITH AND WITHOUT SPRING OR FALL AMMONIUM NITRATE APPLICATIONS". Canadian Journal of Soil Science 67, n. 2 (1 maggio 1987): 367–82. http://dx.doi.org/10.4141/cjss87-032.
Testo completoAbstract (sommario):
Nitrogen in fallow soil in four field trials was monitored at Agassiz to examine the response of N processes under humid weather conditions of south coastal British Columbia. Inorganic N in the soil profile of control and ammonium-nitrate-treated plots were compared at various time intervals. In two trials (Spring-78 and Spring-81) treatments were applied in late May and in two (Fall-79 and Fall-82) in early November. Leaching of spring-applied N was quite limited during the spring and summer. In the Spring-78 trial, there was negligible nitrate movement until September whereas in the Spring-81 trial there was some movement in June. In the Spring-81 trial, upward movement of nitrate was detected in late August. Nitrate leaching in the summer of 1981 was associated with an unusually high amount of precipitation during June. Leaching of nitrate was significant in late October to December. Nitrogen applied in early November showed extensive leaching by late December. The ammonium appeared to have been nitrified quickly to enable leaching of the applied N as nitrate. Leaching of nitrate appeared to be associated with net water surpluses (precipitation less pan evaporation). Clay fixation of applied ammonium was detected immediately after fertilizer application in the fall but not in the spring trials. The applied ammonium that was fixed by clay was apparently released during the monitoring period. An increase of surface acidity due to ammonium nitrate application was detected in the Fall-79 trial. Comparison of nitrate leaching with long-term precipitation and pan-evaporation records shows that there is low risk of nitrate leaching during the spring and summer but high risk during the fall and winter in south coastal British Columbia. It was concluded that residual inorganic N after the growing season would not be available for crop growth in the spring due to nitrification and leaching over the winter. Development of a soil test for N would have to concentrate on the potential of the soil to mineralize soil N in the spring and early summer. Key words: Nitrogen leaching, nitrogen transformations, clay fixed NH4+, nitrification, fall nitrogen application
17
Lilburne, L. R., T. H. Webb e G. S. Francis. "Relative effect of climate, soil, and management on risk of nitrateleaching under wheat production in Canterbury, New Zealand". Soil Research 41, n. 4 (2003): 699. http://dx.doi.org/10.1071/sr02083.
Testo completoAbstract (sommario):
The GLEAMS simulation model was used to determine the relative effects of climate (19 years of data), soil type (4 soils distinguished by effective soil depth), and farm management (6 sowing dates and 5 levels of nitrogen fertiliser) on leaching of nitrate under wheat production. All combinations of inputs were simulated and the effects of each input were estimated with sensitivity analysis software (SimLab). Soil type, climate, and sowing date explained about equal amounts of the variance in nitrate leaching, whereas fertiliser application explained only about one-third of the variance of the other inputs. The 2 most significant results were: (1) the importance of having plant uptake of nitrogen during autumn and winter to limit nitrate availability for leaching, and (2) the recognition that leaching of nitrate becomes increasingly sensitive to farm management practices with decreasing soil depth. The risk of nitrate leaching was found to be very low on deep soils when the crop was sowed in the autumn or winter. These results help with identifying areas where management changes might be effective in reducing the long-term risk of nitrate leaching. Crop growth over winter and judicious use of fertiliser are particularly recommended for cropping on shallow soils.
18
Koós, Sándor, Béla Pirkó, Gábor Szatmári, Péter Csathó, Marianna Magyar, József Szabó, Nándor Fodor et al. "Influence of the Shortening of the Winter Fertilization Prohibition Period in Hungary Assessed by Spatial Crop Simulation Analysis". Sustainability 13, n. 1 (5 gennaio 2021): 417. http://dx.doi.org/10.3390/su13010417.
Testo completoAbstract (sommario):
The Nitrates Directive aims (a) to protect water quality across Europe from nitrates originating from agricultural sources that pollute ground and surface water, and (b) to promote good farming practices. One of the most controversial measures of the directive is the winter prohibition period of fertilization, which has been extended by a month in two steps in recent years. According to the regulation, it is forbidden to apply nitrogen fertilization in Hungary between 31st October and 15th February, even though the winter climate is gradually becoming milder. Using the fertilization data of nearly half a million parcels of land in the Hungarian Nitrate Database, a crop model-based spatial analysis was carried out. Our aim was to test if a shift in the prohibition period starting date from 31st October to 30th November caused any differences in the nitrate amount leached at a 90 cm depth. Detailed nitrate inputs and soil and weather databases were coupled with the 4M crop model. The yield, plant nitrogen uptake, and nitrate leaching under five major crops were simulated, covering a considerable portion of arable land. Shifting the prohibition period starting date did not result in significant changes in the nitrate leaching. Further runs of the 4M model with different weather scenarios are needed to decide whether the modification of the prohibition period significantly affects the amount of nitrate leached.
19
JONES, R. DAVID, e A. PAUL SCHWAB. "NITRATE LEACHING AND NITRITE OCCURRENCE IN A FINE-TEXTURED SOIL". Soil Science 155, n. 4 (aprile 1993): 272–82. http://dx.doi.org/10.1097/00010694-199304000-00006.
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Swinton, Scott M., e David S. Clark. "Farm-Level Evaluation of Alternative Policy Approaches to Reduce Nitrate Leaching from Midwest Agriculture". Agricultural and Resource Economics Review 23, n. 1 (aprile 1994): 66–74. http://dx.doi.org/10.1017/s1068280500000423.
Testo completoAbstract (sommario):
Policies to reduce nitrate leaching are evaluated using a mixed integer linear programming model of a representative Michigan cash grain farm. At spring 1993 prices, elimination of the current deficiency payment program is found to be more efficient at reducing leaching than a nitrogen input tax, a tax credit on biologically fixed nitrogen, a rotation payment, or obligatory use of the Integrated Farm Management Program Option (IFMPO). However, elimination of the deficiency payment program would significantly reduce farm income. Modeling risk management and nitrate leaching dynamics are useful extensions of this research, as is estimating the benefits from averting nitrate leaching.
21
Németh, T., L. Pásztor e J. Szabó. "Stochastic modelling of N-leaching using gis and multivariate statistical methods". Water Science and Technology 38, n. 10 (1 novembre 1998): 191–97. http://dx.doi.org/10.2166/wst.1998.0401.
Testo completoAbstract (sommario):
After the growing season, a part of the nitrogen remains in forms sensitive to changes of the conditions, such as nitrate. In years with above-average precipitation a significant amount of nitrate can leave the rooting zone. Integration of knowledge related to environmental conditions of a certain area with the soil, water, and crop management practices helps to prevent the simultaneity of the unfavourable processes leading to nitrate leaching, thus water resources may be protected from nitrate pollution of agricultural origin. In our work we present a stochastic approach for the evaluation of the vulnerability of soils for nitrate leaching. The method was applied for mapping N-leaching hazard in Hungary at a scale of 1:1M.
22
Solomon, Rejoice Ibrahim. "Biochar Amendments for Reducing Nitrate Leaching from Soils of Different Textural Classes in the Nigerian Savanna". Turkish Journal of Agriculture - Food Science and Technology 10, n. 8 (24 agosto 2022): 1363–68. http://dx.doi.org/10.24925/turjaf.v10i8.1363-1368.4855.
Testo completoAbstract (sommario):
This study was carried out with the aim of assessing the effectiveness of four biochar materials; in reducing nitrate leaching from soils of three different textural classes in the Nigerian Savanna region. Soil samples (0-20 cm depth) were collected from three different soil types and three different locations each in the Nigerian Savanna using stratified random sampling. Two hundred and fifty (250) g of soil samples were amended with 0, 2.5, 5, 7.5 and 10 tonha-1 of Maize cob biochar (MCB), rice husk biochar (RHB), cow dung biochar (CDB) and poultry litter biochar (PLB) and were subjected to laboratory leaching experiment. Sixty (60) ml of nutrient solutions containing 300 mgl-1 nitrate using ammonium nitrate (NH4NO3) was applied to each of the laboratory biochar-incubated soil columns to study biochar effect on nutrients retention and transport. The experiment was laid in a Randomize Complete Block Design (RCBD) replicated three times. Leachates were collected and nitrate concentration was determined using a dual beam UV/VIS spectrophotometer. The data collected were analysed using the Generalized Linear Model (GLM) procedure and the means were separated using Tukey’s honest significant difference (SAS version 9.4). Results obtained revealed that there were no significant differences among the biochar treatments on nitrate leaching from Clay loam. However, highest nitrate leaching from Loamy soil of 30.53% was recorded by the application of 2.5 tonha-1 PLB and was significantly different from the application of 2.5 and 5-ton ha-1 RHB and 5-ton ha-1 MCB. Similarly, highest nitrate leaching from Sandy loam of 32.18 % was recorded by the application of 5-ton ha-1 MCB and was significantly higher than 5.94, 2.40 and 7.12 % recorded by the application of 2.5 and 5-ton ha-1 RHB and 7.5 tonha-1 CDB respectively. Therefore, application of 2.5, 5-ton ha-1 RHB and 7.5 tonha-1 CDB can effectively reduce nitrate leaching from Sandy loam. While 2.5, 5, 7.5 tonha-1 CDB and 2. 5 and 5 tonha-1 RHB reduced nitrate leaching from Loamy soils.
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Curk, Miha, Matjaž Glavan e Marina Pintar. "Analysis of Nitrate Pollution Pathways on a Vulnerable Agricultural Plain in Slovenia: Taking the Local Approach to Balance Ecosystem Services of Food and Water". Water 12, n. 3 (5 marzo 2020): 707. http://dx.doi.org/10.3390/w12030707.
Testo completoAbstract (sommario):
Groundwater pollution with nitrate of agricultural origin is a major problem in many countries. A great deal of effort is focused on finding ways to reduce leaching from agricultural land. In this study, different land management scenarios were evaluated with the SWAT model in order to determine which are the most effective in reducing nitrate leaching on specific soil types in the Krška kotlina alluvial plain (Slovenia). The area is very important both for agriculture production and drinking water resources. The model was calibrated for three soil moisture field trial sites, each representing one major soil type of the area. Simulated soil moisture values were in good agreement with the observed values (PBIAS (percent bias) ±25%). Of the nine land management scenarios that were evaluated, vegetable rotation caused the most nitrate leaching on all soil types, but it fared better on Cambisol than on Fluvisol. Orchards on the other hand leached the least amount of nitrate, but also fared better on Cambisol. Presented studies should be considered as a preliminary stage in the study of nitrate pollution in the investigated area. Results show that nitrate leaching varies for different land management scenarios on different soil types. Further work should concentrate on field trials to evaluate the impacts of reduced fertilization on nitrate leaching and both crop yield and quality on different soil types.
24
Huber, B., J. Luster, S. M. Bernasconi, J. Shrestha e E. Graf Pannatier. "Nitrate leaching from short-hydroperiod floodplain soils". Biogeosciences Discussions 9, n. 5 (14 maggio 2012): 5659–94. http://dx.doi.org/10.5194/bgd-9-5659-2012.
Testo completoAbstract (sommario):
Abstract. Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3–) contamination coming from adjacent agricultural land. Much less is known about nitrogen (N) transformations and nitrate fluxes in riparian soils with short hydroperiods (1–3 days of inundation) and there is no study that could show whether these soils are a N sink or source. Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm) over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation) and N output (leaching) to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater. Overall, the main factor explaining the differences in nitrate concentrations was the variability in soil texture and volumetric water content (VWC) at field capacity (FC). In subsoils with high VWC at FC and VWC near 100 % FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol l−1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha−1 yr−1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3– ha−1 yr−1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11 % to the total nitrate load in groundwater.
25
Huber, B., J. Luster, S. M. Bernasconi, J. Shrestha e E. Graf Pannatier. "Nitrate leaching from short-hydroperiod floodplain soils". Biogeosciences 9, n. 11 (9 novembre 2012): 4385–97. http://dx.doi.org/10.5194/bg-9-4385-2012.
Testo completoAbstract (sommario):
Abstract. Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3−) contamination coming from adjacent agricultural land. Much less is known about nitrogen (N) transformations and nitrate fluxes in riparian soils with short hydroperiods (1–3 days of inundation) and there is no study that could show whether these soils are a N sink or source. Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm) over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation) and N output (leaching) to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater. Overall, the main factor explaining the differences in nitrate concentrations was the field capacity (FC). In subsoils with high FCs and VWC near FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol L−1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha−1 yr−1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3− ha−1 yr−1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11% to the total nitrate load in groundwater.
26
Haberle, Jan, Pavel Svoboda, Tomáš Šimon, Gabriela Kurešová, Barbora Henzlová e Jan Klír. "Distribution of Mineral Nitrogen in Soil in Relation to Risk of Nitrate Leaching in Farms with Irrigated Vegetables and Early Potatoes". Journal of Horticultural Research 26, n. 2 (1 dicembre 2018): 47–54. http://dx.doi.org/10.2478/johr-2018-0015.
Testo completoAbstract (sommario):
Abstract Vegetable production may be the source of excessive residual nitrate that is prone to leaching to waters. To ascertain the risk of nitrate leaching in water collection area, the content of soil mineral nitrogen (Nmin = N-NO3− + N-NH4+) down to 120 cm depth was monitored in the years 2013–2016 on vegetable farms along lower Jizera river (in the Czech Republic). The risk of nitrate leaching below 30, 60, 90 and 120 cm during winter period was simulated with a simple model. The depths represent the limits of effective root depth and N depletion of groups of vegetables and field crops. The average autumn mineral nitrogen content in the fields, during experimental years, ranged from 101 kg to 134 kg N·ha−1 in the 0–120 cm soil layer, 85 to 92% of which was in the form of nitrate. The calculated leaching of nitrate from the topsoil (0–30 cm) and shallow subsoil (0–60 cm) ranged from 27 to 41%, and from 7 to 14% of autumn content, respectively. The risk of leaching below 60 cm and 90 cm was near to none during the experimental years due to the exceptionally low precipitation. High nitrate content in subsoil layers below 60 cm constitutes risk of leaching and water pollution due to shallow root systems of many vegetables and potatoes in seasons with normal weather and higher water percolation.
27
Shekofteh, Hosein, Majid Afyuni, Mohammad Ali Hajabbasi, Bo V. Iversen, Hossein Nezamabadi-pour, Fariborz Abassi e Farid Sheikholeslam. "Nitrate leaching from a potato field using adaptive network-based fuzzy inference system". Journal of Hydroinformatics 15, n. 2 (21 novembre 2012): 503–15. http://dx.doi.org/10.2166/hydro.2012.075.
Testo completoAbstract (sommario):
The conventional methods of application of nitrogen fertilizers might be responsible for the increased nitrate concentration in groundwater of areas dominated by irrigated agriculture. Appropriate water and nutrient management strategies are required to minimize groundwater pollution and to maximize nutrient use efficiency and production. Design and operation of a drip fertigation system requires understanding of nutrient leaching behavior in cases of shallow rooted crops such as potatoes which cannot extract nutrient from a lower soil depth. This study deals with neuro-fuzzy modeling of nitrate (NO3−) leaching from a potato field under a drip fertigation system. In the first part of the study, a two-dimensional solute transport model was used to simulate nitrate leaching from a sandy soil with varying emitter discharge rates and fertilizer doses. The results from the modeling were used to train and validate an adaptive network-based fuzzy inference system (ANFIS) in order to estimate nitrate leaching. Two performance functions, namely mean absolute percentage error (MAPE) and correlation coefficient (R), were used to evaluate the adequacy of the ANFIS. Results showed that ANFIS can accurately simulate HYDRUS-2D behavior regarding nitrate leaching under the circumstances of the present study.
28
Dapeng, Wang, Zheng Liang, Gu Songdong, Shi Yuefeng, Liang Long, Meng Fanqiao, Guo Yanbin, Ju Xiaotang e Wu Wenliang. "Soil nitrate accumulation and leaching in conventional, optimized and organic cropping systems". Plant, Soil and Environment 64, No. 4 (20 aprile 2018): 156–63. http://dx.doi.org/10.17221/768/2017-pse.
Testo completoAbstract (sommario):
Excessive nitrogen (N) and water input, which are threatening the sustainability of conventional agriculture in the North China Plain (NCP), can lead to serious leaching of nitrate-N (NO<sub>3</sub><sup>–</sup>-N). This study evaluates grain yield, N and water consumption, NO<sub>3</sub><sup>–</sup>-N accumulation and leaching in conventional and two optimized winter wheat-summer maize double-cropping systems and an organic alfalfa-winter wheat cropping system. The results showed that compared to the conventional cropping system, the optimized systems could reduce N, water consumption and NO<sub>3</sub><sup>–</sup>-N leaching by 33, 35 and 67–74%, respectively, while producing nearly identical grain yields. In optimized systems, soil NO<sub>3</sub><sup>–</sup>-N accumulation within the root zone was about 80 kg N/ha most of the time. In the organic system, N input, water consumption and NO<sub>3</sub><sup>–</sup>-N leaching was reduced even more (by 71, 43 and 92%, respectively, compared to the conventional system). However, grain yield also declined by 46%. In the organic system, NO<sub>3</sub><sup>–</sup>-N accumulation within the root zone was generally less than 30 kg N/ha. The optimized systems showed a considerable potential to reduce N and water consumption and NO<sub>3</sub><sup>–</sup>-N leaching while maintaining high grain yields, and thus should be considered for sustainable agricultural development in the NCP.
29
Asibi, Aziiba Emmanuel, Wen Yin, Falong Hu, Zhilong Fan, Zhiwen Gou, Hongwei Yang, Yao Guo e Qiang Chai. "Optimized nitrogen rate, plant density, and irrigation level reduced ammonia emission and nitrate leaching on maize farmland in the oasis area of China". PeerJ 10 (19 gennaio 2022): e12762. http://dx.doi.org/10.7717/peerj.12762.
Testo completoAbstract (sommario):
Nitrogen fertilizers play a key role in crop production to meet global food demand. Inappropriate application of nitrogen fertilizer coupled with poor irrigation and other crop management practices threaten agriculture and environmental sustainability. Over application of nitrogen fertilizer increases nitrogen gas emission and nitrate leaching. A field experiment was conducted in China’s oasis irrigation area in 2018 and 2019 to determine which nitrogen rate, plant density, and irrigation level in sole maize (Zea mays L.) cropping system reduce ammonia emission and nitrate leaching. Three nitrogen rates of urea (46-0-0 of N-P2O5-K2O), at (N0 = 0 kg N ha−1, N1 = 270 kg N ha−1, and N2 = 360 kg N ha−1) were combined with three plant densities (D1 = 75,000 plants/ha−1, D2 = 97,500 plants/ha−1, and D3 = 120,000 plants/ha−1) with two irrigation levels (W1 = 5,250 m3/hm2 and W2 = 4,740 m3/hm2) using a randomized complete block design. The results showed that, both the main and interaction effects of nitrogen rate, plant density, and irrigation level reduced nitrate leaching (p < 0.05). In addition, irrigation level × nitrogen rate significantly (p < 0.05) reduced ammonia emission. Nitrate leaching and ammonia emission decreased with higher irrigation level and higher plant density. However, high nitrogen rates increased both nitrate leaching and ammonia emission. The study found lowest leaching (0.35 mg kg−1) occurring at the interaction of 270 kg N ha−1 × 120,000 plants/ha−1 × 4,740 m3/hm2, and higher plant density of 120,000 plants/ha−1 combined with 0 kg N ha−1 and irrigation level of 5,250 m3/hm2 recorded the lowest ammonia emission (0.001 kg N)−1. Overall, ammonia emission increased as days after planting increased while nitrate leaching decreased in deeper soil depths. These findings show that, though the contributory roles of days after planting, soil depth, amount of nitrogen fertilizer applied and year of cultivation cannot be undermined, it is possible to reduce nitrate leaching and ammonia emission through optimized nitrogen rate, plant density and regulated irrigation for agricultural and environmental sustainability.
30
Pandorf, Madelyn, Leila Pourzahedi, Leanne Gilbertson, Gregory V. Lowry, Pierre Herckes e Paul Westerhoff. "Graphite nanoparticle addition to fertilizers reduces nitrate leaching in growth of lettuce (Lactuca sativa)". Environmental Science: Nano 7, n. 1 (2020): 127–38. http://dx.doi.org/10.1039/c9en00890j.
Testo completoAbstract (sommario):
This study focused on nitrate leaching through soil during growth of romaine lettuce where 2-D graphite (CNPs) were combined with fertilizer and applied to soil to test the CNP effect on yield, nitrate leaching, and plant nutrient uptake.
31
Heinrich, Aaron, Richard Smith e Michael Cahn. "Winter-killed Cereal Rye Cover Crop Influence on Nitrate Leaching in Intensive Vegetable Production Systems". HortTechnology 24, n. 5 (ottobre 2014): 502–11. http://dx.doi.org/10.21273/horttech.24.5.502.
Testo completoAbstract (sommario):
High levels of residual soil nitrate are typically present in cool-season vegetable fields in coastal regions of California in the fall, after the production of multiple crops over the course of the growing season. This nitrate is subject to leaching with winter rains when fields are left fallow. Although the benefits of growing nitrate scavenging cover crops on soil and water quality are well documented, the portion of vegetable production fields planted to winter cover crops in this region is low. Most growers leave their fields unplanted in bare-fallow beds because the risk of having too much cover crop residue to incorporate may delay late winter and early spring planting schedules. A possible strategy to derive benefits of a cover crop yet minimize the amount of residue is to kill the cover crop with an herbicide when biomass of the cover crop is still relatively low. To evaluate whether this strategy would be effective at reducing nitrate leaching, we conducted field studies in Winter 2010–11 (Year 1) and Winter 2011–12 (Year 2) with cereal rye (Secale cereale). Each trial consisted of three treatments: 1) Fallow (bare fallow), 2) Full-season (cover crop allowed to grow to full term), and 3) Partial-season (cover crop killed with herbicide 8 to 9 weeks after emergence). In Year 1, which received 35% more rainfall than the historical average during the trial, the Full-season cover crop reduced nitrate leaching by 64% relative to Fallow, but the Partial-season had no effect relative to Fallow. In Year 2, which received 47% less rainfall than the historical average during the trial, the Full- and Partial-season cover crops reduced nitrate leaching by 75% and 52%, respectively, relative to Fallow. The Full-season cover crop was able to reduce nitrate leaching regardless of yearly variations in the timing and amount of precipitation. Although the Partial-season cover crop was able to reduce leaching in Year 2, the value of this winter-kill strategy to reduce nitrate leaching is limited by the need to kill the crop when relatively young, resulting in the release of nitrogen (N) from decaying residues back into the soil where it is subject to leaching.
32
Luo, Xiaosheng, Changlin Kou e Qian Wang. "Optimal Fertilizer Application Reduced Nitrogen Leaching and Maintained High Yield in Wheat-Maize Cropping System in North China". Plants 11, n. 15 (28 luglio 2022): 1963. http://dx.doi.org/10.3390/plants11151963.
Testo completoAbstract (sommario):
Agricultural nitrogen (N) non-point source pollution in the North China Plain is a major factor that affects water quality and human health. The characteristics of N leaching under different N application conditions should be further quantified accurately in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) rotation farmland in North China, and a basis for reducing the risk and evaluation of N leaching in this area. A three-year field experiment was conducted using an in situ leakage pond method at a typical farmland in Henan in 2017–2020. Crop yield, soil nitrate N residues, and N utilization were also studied during the study period. Five N fertilizer rates were established with 0 (CK), 285 (LN), 465 (MN), 510 (MNO), and 645 (HN) kg N ha−1 for one rotation cycle. MNO was applied with chemical and organic fertilizers. The concentration of nitrate N in the soil leaching solution of CK, LN, MN, MNO, and HN was 0.81-, 1.49-, 3.65-, 5.55-, and 7.57-fold that of the World Health Organization’s standard for underground drinking water. The exponential relationship between the N application rate and leaching was obtained when the annual N input exceeded 300 kg ha−1, and the N leaching rate increased greatly. The leaching rate of nitrate N in the total N was 50.6–82.4% under different treatments of N application. The combination of chemical and organic fertilizers treatment (MNO) reduced the amount of N that was leached in dry years. The nitrate leaching amount of summer maize accounts for 83.0%, 49.4%, and 72.0% of the total nitrate leaching amount of the whole rotation cycles in 2017–2020. LN and MN were recommended as the optimized N application here (285–465 kg N ha−1) with the two-season rotation grain yield of 17.2 ton ha−1 (16.5–17.9 ton ha−1) and nitrate N leaching of 21.6 kg ha−1 (12.6–30.5 kg ha−1).
33
Kaluli, J. Wambua, Chandra A. Madramootoo, Xiaomin Zhou, Angus F. MacKenzie e Donald L. Smith. "Subirrigation Systems to Minimize Nitrate Leaching". Journal of Irrigation and Drainage Engineering 125, n. 2 (marzo 1999): 52–58. http://dx.doi.org/10.1061/(asce)0733-9437(1999)125:2(52).
Testo completo
34
Maynard, Abigail A. "Nitrate Leaching from Compost-Amended Soils". Compost Science & Utilization 1, n. 2 (marzo 1993): 65–72. http://dx.doi.org/10.1080/1065657x.1993.10757875.
Testo completo
35
Østergaard, H. S., B. Stougaard e C. Jensen. "Nitrate Leaching Depending on Cropping Systems". Biological Agriculture & Horticulture 11, n. 1-4 (gennaio 1995): 173–79. http://dx.doi.org/10.1080/01448765.1995.9754703.
Testo completo
36
Goodlass, G., M. Green, B. Hilton e S. McDonough. "Nitrate leaching from short-rotation coppice". Soil Use and Management 23, n. 2 (giugno 2007): 178–84. http://dx.doi.org/10.1111/j.1475-2743.2006.00080.x.
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37
de Vos, J. A. "Monitoring Nitrate Leaching from Submerged Drains". Journal of Environmental Quality 30, n. 3 (maggio 2001): 1092–96. http://dx.doi.org/10.2134/jeq2001.3031092x.
Testo completo
38
Spalding, Roy F., Darrell G. Watts, James S. Schepers, Mark E. Burbach, Mary E. Exner, Robert J. Poreda e Glen E. Martin. "Controlling Nitrate Leaching in Irrigated Agriculture". Journal of Environmental Quality 30, n. 4 (2001): 1184–94. http://dx.doi.org/10.2134/jeq2001.3041184x.
Testo completo
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Wu, Laosheng, Robert Green, Marylynn V. Yates, Porfy Pacheco e Grant Klein. "Nitrate Leaching in Overseeded Bermudagrass Fairways". Crop Science 47, n. 6 (novembre 2007): 2521–28. http://dx.doi.org/10.2135/cropsci2007.01.0042.
Testo completo
40
Ball-Coelho, B. R., R. C. Roy e A. J. Bruin. "Nitrate leaching as affected by liquid swine manure and cover cropping in sandy soil of southwestern Ontario". Canadian Journal of Soil Science 84, n. 2 (1 maggio 2004): 187–97. http://dx.doi.org/10.4141/s03-047.
Testo completoAbstract (sommario):
To assess the risk that liquid swine manure (LSM) application posed to groundwater quality and determine how to manage excess nitrates, LSM pre-plant injected at 75% (LSMlow) and >100% (LSMhigh) of corn (Zea mays L.) N requirements was compared to inorganic fertilizer (Fert), with (RC) or without (NC) a rye (Secale cereale L.) cover crop in 2 dry years (1999, 2001) and 1 wet year (2000) on sandy soil in Ontario. Corn yields in LSM and Fert treatments were comparable each year. When drainage potential was high, solution nitrates below the root zone in Fert (14 mg L-1) > LSM (7 mg L-1) in 1999, but in LSM (39 mg L-1) > Fert (13 mg L-1) in 2000. Occasionally in 2001, solution nitrates in LSMhigh > LSMlow and/or Fert plots, but drainage potential was low. Earlier N application in LSM (pre-plant) than Fert (77% of N sidedressed) plots in relation to rain events may have increased solution nitrates in LSM plots in 2000. Rye cover reduced solution nitrates from 8.8 mg L-1 (NC) to 4.3 mg L-1 (RC, average of all dates), regardless of nutrient source. In-season risk of NO3 leaching can be reduced by split application of N between pre-plant and sidedress, while overseeding cereal rye into standing corn minimizes leaching post-harvest (fall and spring). Key words: Zea mays, Secale cereale, pre-sidedress nitrate test, swine manure, nitrate leaching
41
Trudgill, S. T., T. P. Burt, A. L. Heathwaite e B. P. Arkell. "Soil nitrate sources and nitrate leaching losses, Slapton, South Devon". Soil Use and Management 7, n. 4 (dicembre 1991): 200–206. http://dx.doi.org/10.1111/j.1475-2743.1991.tb00875.x.
Testo completo
42
Merhaut, Donald J., e Julie P. Newman. "(127) Effects of Substrate on Nutrient Uptake and Nitrate Leaching in Lilies". HortScience 40, n. 4 (luglio 2005): 1085E—1086. http://dx.doi.org/10.21273/hortsci.40.4.1085e.
Testo completoAbstract (sommario):
Lilies are produced throughout the year in coastal areas of California. Cultural practices involve daily applications of water and fertilizer, using both controlled release fertilizers (CRF) and liquid fertilizers (LF). However, many production facilities are in proximity to coastal wetlands and are therefore at greater risk of causing nitrogen pollution via runoff and leaching. Due to federal and state regulations, nurseries must present a plan of best management practices (BMPs) to mitigate nutrient runoff and leaching and begin implementing these practices in the next 2 years. In the following studies, we determined the potential for nitrate leaching from four different types of substrates (coir, coir: peat, peat, and native soil). There were four replications of each treatment, with a replication consisting of one crate planted with 25 bulbs. Two cultivars were used in two separate experiments, `Star Fighter' and `Casa Blanca'. Nitrate leaching was determined by placing an ion-exchange resin bag under each crate at the beginning of the study. After plant harvest (14–16 weeks), resin bags were collected and analyzed for nitrate content. Plant tissues were dried and ground and analyzed for nitrogen content. Based on the results of these studies, it appears that the use of coir, peat, and soil may not influence plant growth significantly. Substrate type may mitigate the amount of nitrate leaching through the media. However, the cultivar type may also influence the degree of nitrate mitigation, since leaching results varied between the two cultivars.
43
Gasser, M. O., M. R. Laverdière, R. Lagacé e J. Caron. "Impact of potato-cereal rotations and slurry applications on nitrate leaching and nitrogen balance in sandy soils". Canadian Journal of Soil Science 82, n. 4 (1 novembre 2002): 469–79. http://dx.doi.org/10.4141/s01-050.
Testo completoAbstract (sommario):
Groundwater quality is at risk when high levels of N fertilizers are used on sandy soils. A monitoring program was initiated in the summer of 1995, to quantify nitrate leaching in sandy soils used for potato production near Quebec city, Canada. Three drainable lysimeters were installed in each of five fields, for a total of 15 lysimeters. During a 5-yr monitoring period, crop N uptake, mineral and organic N fertilizers use, nitrate concentrations and fluxes from drainage water at 1-m soil depth were assessed under potato, cereal and hay crops. In one field, a clover and timothy sod that received low mineral N fertilizer inputs generated the lowest annual nitrate leaching losses ranging from 7 to 20 kg NO3-N ha-1. High nitrate leaching losses (116 ± 40 kg N ha-1) were measured under potato crops receiving high mineral N fertilizer inputs. Cereals, including barley and wheat receiving moderate mineral N fertilizer inputs and in some instance N from pig slurry, dairy cow manure or paper mill sludge, also generated high nitrate leaching losses (88 ± 45 kg N ha-1). Only sod and oat crops generated annual flux averaged nitrate concentrations lower than 10 mg NO3-N L-1, the accepted standard for drinking water, while higher concentrations, ranging from 13 to 52 mg NO3-N L-1, were recorded under barley, wheat and potato crops receiving moderate to high amounts of mineral N fertilizer. Nitrate flux concentrations were moderate during the cropping season (May-August), highest in fall (September-December) and lowest in the winter-early spring period (January-April). After 5 yr of survey, use of pig slurry and paper mill sludge in potato-cereal crop rotations (51 to 192 kg N ha-1 annually) with mineral N fertilizers (103 to 119 kg N ha-1 annually) resulted in nitrate leaching losses (87 to 132 kg N ha-1 annually), at least 20 kg N ha-1 more than N exported by crop at harvest. More than 60% of N applied as pig slurry seemed to be unaccounted for in the partial N balance that included crop N uptake and nitrate leaching, suggesting that important losses probably occurred through ammonia volatilization, denitrification, or N immobilization in soil organic matter and crop residues. Key words: Barley, lysimeter, nitrate leaching, nitrogen balance, pig slurry, potato
44
Wong, M. T. F., e K. Wittwer. "Positive charge discovered across Western Australian wheatbelt soils challenges key soil and nitrogen management assumptions". Soil Research 47, n. 1 (2009): 127. http://dx.doi.org/10.1071/sr08098.
Testo completoAbstract (sommario):
Nitrogen management in Western Australia (WA) and in cropping areas elsewhere in Australia assumes that soil contains negligible or no positive charge and is therefore unable to retain nitrate against leaching. The amount of water needed to displace nitrate is thus assumed to be the drainable volume of water held by the soil (1 pore volume), and in sandy soils about 100 mm drainage is assumed to be required to displace nitrate by 1 m. The clay mineralogy of the highly weathered soils of the WA wheatbelt is dominated by kaolinite and iron and aluminium oxides. This mineralogy suggests likely occurrence of positive charge and anion exchange capacity (AEC), since these minerals can carry positive charge under normal acidic field situations. We measured AEC of soils sampled widely across the WA wheatbelt by independent leaching and batch equilibration methods of charge measurement. This showed widespread occurrence of positive charge and AEC in these soils. AEC ranged from 0 to 2.47 mmolc/kg and is linearly correlated with the potassium chloride or monocalcium phosphate extractable sulfate content of the soil. This correlation provides a rapid screening method to identify soils with positive charge. Application of ion-chromatographic theory showed that AEC has a large effect in delaying nitrate leaching by up to 12.5 pore volumes. The most highly charged soil (2.47 mmolc/kg) thus needed 12.5 times more water to displace nitrate than currently assumed. This potentially large delay in nitrate leaching affects the optimum amount and time of fertiliser application, rates of soil acidification attributed to nitrate leaching and the benefit of ameliorating subsoils to allow roots access to subsoil water and leached nitrate. It also calls into question the use of anions such as bromide to trace water flow and estimate recharge in these soils.
45
Yelanich, Mark V., e John A. Biernbaum. "Fertilizer Concentration and Leaching Affect Nitrate-Nitrogen Leaching from Potted Poinsettia". HortScience 29, n. 8 (agosto 1994): 874–75. http://dx.doi.org/10.21273/hortsci.29.8.874.
Testo completoAbstract (sommario):
The influence of fertilizer concentration and leaching volume on the quantity of applied N and water that were leached from a container-grown poinsettia crop (Euphorbia pulcherrima Willd.) was investigated. The NO3-N quantity leached after 71 days increased with higher NO3-N application rates (7, 14, or 28 mol NO3-N/m3) and higher leaching volumes; it ranged from 0.03 g NO3-N [7 mol·m-3, 0.00 container capacity leached (CCL)] to 7.65 g NO3-N (28 mol·m-3, 1.0 CCL). The NO3-N concentration for saturated media extracts increased with lower leaching volumes and higher fertilizer concentrations. For example, when 7 mol NO3-N/m3 was applied, NO3-N in the medium was 27.1 mol NO3-N/m3 when 0 CCL was used, but it was 8.6 mol NO3-N/m3 when 1.0 CCL was used. Shoot height and dry mass were not affected by the treatments. Leaching treatments also did not influenced leaf area, but leaf area was larger at 7 compared to 14 or 28 mol NO3-N/m3.
46
ERIKSEN, J. "Nitrate leaching and growth of cereal crops following cultivation of contrasting temporary grasslands". Journal of Agricultural Science 136, n. 3 (maggio 2001): 271–81. http://dx.doi.org/10.1017/s0021859601008802.
Testo completoAbstract (sommario):
Intensive dairy farming with low N use efficiencies may have adverse environmental impact through nitrate leaching. The residual effects of six different temporary grasslands (1994–96) on yield and nitrate leaching in the following cereal crops (1997–99) were investigated on a loamy sand in central Jutland. The grasslands were unfertilized grass–clover and fertilized ryegrass subject to cutting or continuous grazing by dairy cows with two levels of N in feed supplements. In the first year there was sufficient residual effect of the grazed grasslands to obviate the need for supplementary fertilizer, but in the following years gradually more fertilizer N was required to obtain optimal yields. Nitrate leaching decreased as a function of time after cultivation of grassland, but grassland management had little effect on the subsequent nitrate leaching (6 to 36 kg N/ha in unfertilized plots). Application of cattle slurry to cereals influenced nitrate leaching more than the history of the grassland and caused the annual mean nitrate concentration to exceed the EU Drinking Water Directive upper limit in most cases. Presumably, large differences in N-input during the grassland phase of the crop rotation had relatively little effect on the subsequent N release because of variable N losses during grazing. Possibilities for further improvement of the utilization of grassland N following cultivation are limited when the current knowledge has been implemented. If the N use efficiency of dairy farming systems is to be further improved the utilization of N during the pasture phase is crucial.
47
Beukes, Pierre, Alvaro Romera, Kathryn Hutchinson, Tony van der Weerden, Cecile de Klein, Dawn Dalley, David Chapman, Chris Glassey e Robyn Dynes. "Benefits and Trade-Offs of Dairy System Changes Aimed at Reducing Nitrate Leaching". Animals 9, n. 12 (17 dicembre 2019): 1158. http://dx.doi.org/10.3390/ani9121158.
Testo completoAbstract (sommario):
Between 2011 and 2016, small-scale farm trials were run across three dairy regions of New Zealand (Waikato, Canterbury, Otago) to compare the performance of typical regional farm systems with farm systems implementing a combination of mitigation options most suitable to the region. The trials ran for at least three consecutive years with detailed recording of milk production and input costs. Nitrate leaching per hectare of the milking platform (where lactating cows are kept) was estimated using either measurements (suction cups), models, or soil mineral nitrogen measurements. Post-trial, detailed farm information was used in the New Zealand greenhouse gas inventory methodology to calculate the emissions from all sources; dairy platform, dairy support land used for wintering non-lactating cows (where applicable) and replacement stock, and imported supplements. Nitrate leaching was also estimated for the support land and growing of supplements imported from off-farm using the same methods as for the platform. Operating profit (NZ$/ha/year), nitrate leaching (kg N/ha/year), and greenhouse gas emissions (t CO2-equivalent/ha/year) were all expressed per hectare of milking platform to enable comparisons across regions. Nitrate leaching mitigations adopted in lower-input (less purchased feed and nitrogen fertiliser) farm systems reduced leaching by 22 to 30 per cent, and greenhouse gas emissions by between nine and 24 per cent. The exception was the wintering barn system in Otago, where nitrate leaching was reduced by 45 per cent, but greenhouse gas emissions were unchanged due to greater manure storage and handling. Important drivers of a lower environmental footprint are reducing nitrogen fertiliser and purchased feed. Their effect is to reduce feed flow through the herd and drive down both greenhouse gas emissions and nitrate leaching. Emission reductions in the lower-input systems of Waikato and Canterbury came at an average loss of profit of approximately NZ$100/t CO2-equivalent (three to five per cent of industry-average profit per hectare).
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Burkitt, Lucy L. "A review of nitrogen losses due to leaching and surface runoff under intensive pasture management in Australia". Soil Research 52, n. 7 (2014): 621. http://dx.doi.org/10.1071/sr13351.
Testo completoAbstract (sommario):
This paper reviews the literature on nitrate leaching and nitrogen (N) runoff under intensive dairy pasture systems in Australia and draws comparisons with research undertaken under similar climates and farming systems internationally, with the aim to inform future research in this area. An Australian nitrate-leaching study suggests that annual nitrate-leaching loads are lower (3.7–14.5 kg N ha–1 year–1 for nil N and 6–22 kg N ha–1 year–1 for 200 kg N ha–1 applied) than the range previously measured and modelled on New Zealand dairy farms (~18–110 kg N ha–1 year–1). It is likely that nitrate-leaching rates are higher in New Zealand because of the prevalence of free-draining soils and higher average stocking rates. However, this review highlights that there are insufficient Australian nitrate-leaching data, particularly following urine application, to undertake a rigorous comparison. Median N surpluses on Australian dairy farms are higher (198 kg N ha–1) than values for an average New Zealand farm (135 kg N ha–1). Given the facts that many soils used for intensive pasture production in Australia are lightly textured or free-draining clay loams receiving average rainfall of >800 mm year–1, that herd sizes have risen in the last 10 years and that water quality is a concern in some dairy catchments, nitrate leaching could be an issue for the Australian dairy industry. Australian data on surface runoff of N are more available, despite its overall contribution to N losses being low (generally <5 kg N ha–1 year–1), except under border-check flood irrigation or hump-and-hollow surface drainage (3–23 kg N ha–1 year–1). More research is needed to quantify surface N runoff and leaching following effluent application and to examine dissolved organic forms of N loss, particularly in view of the continued intensification of the Australian dairy industry.
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El-Sadek, Alaa. "Modeling of Nitrate Leaching during the Fall–Winter Season in Artificially Drained Soils". Scientific World JOURNAL 2 (2002): 1006–16. http://dx.doi.org/10.1100/tsw.2002.204.
Testo completoAbstract (sommario):
The nitrogen processes that occur within the soil play a major role in determining the nitrate leaching to shallow groundwater. In this study, the transport and fate of nitrate within the soil profile were analyzed by comparing field data with the simulation results of a mathematical model. The objective was to study the transport and fate of nitrate within the soil profile and nitrate leaching to shallow groundwater for the fall-winter season, by applying the methodology in Elverdinge experiment, situated in the sandy loam region in Belgium, from October 1, 2000 to March 31, 2001. The analysis by comparing field data with the simulation results of DRAINMOD-N model is given. The research indicated that the DRAINMOD-N model can, after calibration and validation, be used as a useful fertilizer management tool in predicting the nitrate transport and transformation in the soil profile and the nitrate leaching to shallow groundwater and surface waters. The model can also be used as an environmental control when the environmental objective has a greater importance than profits in the agriculture field.
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Zhao, Hui, Xuyong Li e Yan Jiang. "Response of Nitrogen Losses to Excessive Nitrogen Fertilizer Application in Intensive Greenhouse Vegetable Production". Sustainability 11, n. 6 (13 marzo 2019): 1513. http://dx.doi.org/10.3390/su11061513.
Testo completoAbstract (sommario):
Excessive nitrogen fertilizer application in greenhouse vegetable production (GVP) is of scientific and public concern because of its significance to international environmental sustainability. We conducted a meta-analysis using 1174 paired observations from 69 publications on the effects of nitrogen fertilizer application and reducing nitrogen fertilizer application on the nitrogen losses on a broad scale. We found that the increase in nitrogen loss is much higher than that in production gain caused by excessive application of nitrogen fertilizer: nitrate leaching (+187.5%), ammonium leaching (+28.1%), total nitrogen leaching (+217.0%), nitrous oxide emission (+202.0%), ammonia emission (+176.4%), nitric oxide emission (+543.3%), yield (+35.7%) and nitrogen uptake (+24.5%). Environmental variables respond nonlinearly to nitrogen fertilizer application, with severe nitrate leaching and nitrous oxide emission when the application rate exceeds 570 kg N/ha and 733 kg/N, respectively. The effect of nitrogen fertilizer on yield growth decreases when the application rate exceeds 302 kg N/ha. Appropriate reduction in nitrogen fertilizer application rate substantially mitigates the environmental cost, for example, decreasing nitrate leaching (−32.4%), ammonium leaching (−6.5%), total nitrogen leaching (−37.3%), ammonia emission (−28.4%), nitrous oxide emission (−38.6%) and nitric oxide emission (−8.0%), while it has no significant effect on the nitrogen uptake and yield.