scholarly journals The effect of decreasing fertilization on agricultural nitrogen leaching: a model study

2008 ◽  
Vol 16 (4) ◽  
pp. 376 ◽  
Author(s):  
K. GRANLUND ◽  
I. BÄRLUND ◽  
T. SALO

In Finland, the use of agricultural nitrogen (N) fertilizers has decreased since the beginning of the 1990’s but there is not yet any clear response in observed water quality in the monitored agricultural catchments and river basins. It is therefore important to analyse how the reduction in N fertilization affects N leaching at the root zone scale. In this study the nutrient leaching model ICECREAM was used to demonstrate the effects of climatic conditions and decreased N input on N leaching. Ten years (1991–2000) of climatic input data from five stations located in different parts of the country were used as input to simulate nitrate N (NO3-N) leaching from barley cultivation with i) constant N fertilization (Baseline simulation, 90 kg N ha–1) and ii) decreasing N fertilization (N Reduction Scenario simulation: annual linear decrease from 110 to 90 kg N ha–1). The annual and regional variation of simulated N leaching was considerable in both the Baseline and N Reduction Scenario simulations. In the Baseline simulation the average annual NO3-N leaching was 24% of the N fertilization amount. From 1991 to 2000, the annual N leaching decreased close to Baseline leaching values in the N Reduction Scenario simulations, but the decrease was not linear due to high variability in N losses caused by changes in annual weather conditions. The model results indicate that it is possible to achieve a reduction in root zone N leaching by adjusting the fertilizer levels.;

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. W. McDowell ◽  
Z. P. Simpson ◽  
A. G. Ausseil ◽  
Z. Etheridge ◽  
R. Law

AbstractUnderstanding the lag time between land management and impacts on riverine nitrate–nitrogen (N) loads is critical to understand when action to mitigate nitrate–N leaching losses from the soil profile may start improving water quality. These lags occur due to leaching of nitrate–N through the subsurface (soil and groundwater). Actions to mitigate nitrate–N losses have been mandated in New Zealand policy to start showing improvements in water quality within five years. We estimated annual rates of nitrate–N leaching and annual nitrate–N loads for 77 river catchments from 1990 to 2018. Lag times between these losses and riverine loads were determined for 34 catchments but could not be determined in other catchments because they exhibited little change in nitrate–N leaching losses or loads. Lag times varied from 1 to 12 years according to factors like catchment size (Strahler stream order and altitude) and slope. For eight catchments where additional isotope and modelling data were available, the mean transit time for surface water at baseflow to pass through the catchment was on average 2.1 years less than, and never greater than, the mean lag time for nitrate–N, inferring our lag time estimates were robust. The median lag time for nitrate–N across the 34 catchments was 4.5 years, meaning that nearly half of these catchments wouldn’t exhibit decreases in nitrate–N because of practice change within the five years outlined in policy.


Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 113 ◽  
Author(s):  
Mariangela Diacono ◽  
Paola Baldivieso-Freitas ◽  
Francisco Sans Serra

Optimization of the nitrogen (N) inputs and minimization of nutrient losses strongly affect yields in crop rotations. The aim of this research was to evaluate the effect of agricultural practices on yield and N use in a 4-year cereal-legume rotation in organic farming and to identify the best combination of these practices. The following treatments were compared: conventional plough (P) vs. reduced chisel (RC) tillage; composted farmyard manure (F) vs. unfertilized control (NF); and green manure (GM) vs. no green manure (NoM). No significant differences were found for N use efficiency between P and RC in each crop. The results suggested that legumes in the tested rotation do not need supplemental N fertilization, particularly if combining GM and F. The use of composted farmyard manure should be considered in a long-term fertilization plan for cereals, to allow a higher efficiency in N use. The residual effect of fertilization over time, along with the site-specific pedo-climatic conditions, should also be considered. In both tested tillage approaches, soil N surplus was the highest in plots combining GM and F (i.e., more than 680 kg N ha−1 in combination with RC vs. about 140 kg N ha−1 for RC without fertilization), with a risk of N losses by leaching. The N deficit in NoM–NF both combined with P and RC would indicate that these treatment combinations are not sustainable for the utilized crops in the field experiment. Therefore, the combination of the tested practices should be carefully assessed to sustain soil fertility and crop production.


1996 ◽  
Vol 76 (4) ◽  
pp. 783-789 ◽  
Author(s):  
H. J. Beckie ◽  
S. A. Brandt

The response of sunola (Helianthus annuus L. 'AC Sierra') to nitrogen (N) fertilization under conventional and direct seeding tillage systems was examined in field experiments at sites in the semiarid Dark Brown and subhumid Black soil climatic zones over a 2-yr period of normal to above-normal growing season precipitation. Urea-N fertilizer was banded at the time of seeding at varying rates to a maximum of 150 kg N ha−1. Tillage treatment did not influence sunola response to N fertilization. Sunola seed yield responded greater to fertilization at the Black soil site compared with the Dark Brown soil site in both years. Sunola harvest indices were comparable across sites and years, ranging from 0.10 to 0.18. Seed oil concentration averaged about 4% higher at the Black compared with the Dark Brown soil site, and responded to fertilization differently between locations. Sunola water use efficiency was markedly higher in 1994 than in 1993 at both sites, primarily due to lower water consumption by the crop. Fertilizer recommendations can be based on a desired yield goal or marginal rate of return. A minimum acceptable marginal rate of return of 1, 1.5 and 2 times the cost of the fertilizer, indicated that fertilizer N plus soil nitrate-N levels of greater than 94, 66 and 38 kg N ha−1, respectively, were uneconomical at Scott; respective rates at Melfort were 183, 174 and 154 kg N ha−1. However, fertilizer rates in excess of 100 kg N ha−1 in the Black soil climatic zone can result in potentially high levels of residual nitrate-N in the soil profile, and thus have greater potential for N leaching and denitrification losses. Key words:Helianthus annuus L., nitrogen


1997 ◽  
Vol 128 (1) ◽  
pp. 79-86 ◽  
Author(s):  
K. SIELING ◽  
O. GÜNTHER-BORSTEL ◽  
H. HANUS

Nitrogen (N) fertilizer not used by the crop can increase the risk of nitrate leaching into the groundwater. In two growing seasons, 1990/91 and 1991/92, the relationships between N fertilization and yield, N uptake by the grain and the N leaching in the subsequent percolation period were investigated in a multifactorial field experiment at Hohenschulen Experimental Station near Kiel in NW Germany. The crop rotation was oilseed rape – winter wheat – winter barley, and effects of soil tillage (minimum tillage without ploughing, conventional tillage), application of pig slurry (none, application in autumn, application in autumn and in spring), mineral N fertilization (none, 80 or 200 kg N ha−1 to oilseed rape and 120 or 240 kg N ha−1 to cereals) and application of fungicides (none, intensive) were all tested. In each year, the rotation and the treatments were located on the same plots. Mineral N fertilization and fungicide application increased yield and N uptake by grain or seed in all crops. In contrast, the application of slurry, especially in autumn, had only small effects on yield and N uptake. Nitrogen losses by leaching (measured using porous ceramic cups) were affected mainly by the year and the crop. In 1992/93, averaged over all factors, 80 kg N ha−1 was leached compared with 28 kg N ha−1 the previous year. Oilseed rape reduced N losses, whereas under winter wheat up to 160 kg N ha−1 was leached. Due to a lower N-use efficiency, autumn applications of slurry increased N leaching, and mineral N fertilization of the preceding crop also led to higher N losses.Since the amount of leached N depends both on the nitrogen left by the preceding crop (unused fertilizer N as well as N in residues) and on N uptake by the subsequent crop, it is not possible to apportion the N losses to any particular crop in the rotation. The cropping sequence, together with its previous and subsequent crops, must also be considered.To minimize leaching, N fertilization must meet the needs of the growing crop. In order to improve the efficiency further, investigations must be conducted in order to understand the dynamics of N in the plant–soil system in conjunction with the weather and crop management practices.


2019 ◽  
pp. 1383-1387
Author(s):  
Luiz Antônio Zanão Júnior ◽  
Antônio Costa ◽  
Roberto dos Anjos Reis Júnior ◽  
Jéssica C. Urbanski Laureth

Urea fertilizers coated with polymers are used to optimize nitrogen (N) uptake by crops. However, there are many types of polymers that can be used for coating, leading to differences in observed results. Consequently, validation of this technology to guarantee its viability in agriculture is necessary. The objective of this study was to evaluate effects of ammonium- and nitrate-N levels in the soil, maize yield and nutritional status, N fertilization efficiency with Policote® urea coating, and different N doses under various soil and climatic conditions. Three field experiments were carried out to compare the performance of common urea with Policote® coated urea. A (2 x 4) + 1 factorial design with two N sources (common urea and Policote® coated urea), four N doses, and a control treatment (without N) was used. The results showed that Nitrate-N levels in the soil were not affected by the treatments. However, the ammonium-N levels was increased with N fertilization. Higher levels of soil ammonium-N contents were observed in treatments with Policote® coated urea. Foliar nitrogen levels were increased linearly with N doses only in one of the experiments. Nitrogen fertilization significantly increased maize yield. Higher yield and N fertilization efficiency were observed in treatments with Policote® coated urea than with common urea.


2004 ◽  
Vol 84 (4) ◽  
pp. 477-480 ◽  
Author(s):  
T. Q. Zhang ◽  
A. F. MacKenzie ◽  
B. C. Liang

Water samples at zero tension were collected using an open-ended lysimeter and analyzed for NO3−-N from a Chicot sandy clay loam and a Ste. Rosalie clay soil under continuous corn (Zea mays L.) in 1993 and 1994, shortly after spring thaw. There was negligible leaching of NO3−-N at previous fertilizer N rates of 0 and 170 kg ha-1 in both soils. However, NO3−-N concentrations of the leachates from soils receiving 285 and 400 kg N ha-1 yr-1 varied from 1.4 to 80 mg L-1, depending on the initial levels of soil residual NO3−-N and the supply of percolation water. When the initial levels of soil NO3−-N were relatively high and percolation of water was relatively slow in 1993, NO3−-N concentrations of the leachates ranged from 20 to 80 mg L-1. Nitrite-N concentrations were from 1.4 to 15.6 mg L-1 when the initial levels of soil residual NO3−-N were relatively low and percolation was relatively fast in 1994. The occasional higher NO3−-N concentrations in the leachate from the previous higher N applications indicated a potential for contaminating surface and ground waters as a result of NO3−-N leaching in the early spring. Key words: Residual N, nitrate-N leaching, soil solution, continuous corn, N fertilization


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Chaoqiang Jiang ◽  
Dianjun Lu ◽  
Chaolong Zu ◽  
Jia Shen ◽  
Shiji Wang ◽  
...  

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
N. Villar ◽  
M. Aranguren ◽  
A. Castellón ◽  
G. Besga ◽  
A. Aizpurua

Abstract Nitrogen budgets help explain the supply pattern of N from the soil to the crop. Through budgeting, an improvement of the N fertilization strategy can be achieved. The objective of the present study, which was carried out under humid Mediterranean climate conditions, was to assess the influence of N fertilization, temperature and soil humidity on soil N dynamics during a whole oilseed rape growing cycle. A field experiment was conducted with two treatments: without N (0 N) and with application of 180 kg N ha−1(180 N). Mineralization was calculated from N balances made throughout the growing cycle, all while taking into account measured N uptake by oilseed rape and N losses by leaching and N2O emissions. Nitrogen net mineralization was negative after fertilization, reaching –6.73 kg N ha−1, day−1, but total net mineralization over the year was similar for the 0 N and 180 N treatments (21 and 8 kg N ha−1, respectively). Temperatures over 5 °C were sufficient for initiating the mineralization processes. In the summer, when the soil water content was below the wilting point, immobilization took place; however, there is a risk of N leaching if rainfall occurs thereafter, mainly in the 180 N treatment.


Author(s):  
Klepikov O.V. ◽  
Kolyagina N.M. ◽  
Berezhnova T.A. ◽  
Kulintsova Ya.V.

Relevance. Today, in preventive medicine, climatic conditions that have a pathological effect on the functional state of a person are increasingly being updated. the occurrence of exacerbations of many diseases can be causally associated with various weather conditions. Aim: to develop the main tasks for improving the organization of medical care for weather-dependent patients with diseases of the cardiovascular system. Material and methods. The assessment of personnel, material and technical support and the main performance indicators of an outpatient clinic was carried out on the example of the Voronezh city polyclinic No. 18 to develop the main tasks for improving the organization of medical care for weather-dependent patients with diseases of the cardiovascular system. Results. The main personnel problem is the low staffing of district therapists and specialists of a narrow service. One of the priorities for reducing the burden on medical hospitals is the organization of inpatient replacement medical care on the basis of outpatient clinics. The indicators for the implementation of state guarantees for the outpatient network for 2018, which were fully implemented, are given. The analysis of the planned load performance by polyclinic specialists is presented. Cardiological and neurological services carry out measures to reduce the risk of exacerbations of diseases with cerebral atherosclerosis, hypertension, and major neurological nosologies. Conclusion. Improving the organization of medical care for weather-dependent patients with cardiovascular diseases are: informing patients about the sources of specialized medical weather forecasts in the region, organizing the work of the medical prevention office, implementing an interdepartmental approach to providing health care to the most vulnerable groups of the population.


2018 ◽  
Vol 1 (94) ◽  
pp. 55-61
Author(s):  
R.O. Myalkovsky

Goal. The purpose of the research was to determine the influence of meteorological factors on potato yield in the conditions of the Right Bank Forest-steppe of Ukraine. Methods.Field, analytical and statistical. Results.It was established that among the mid-range varieties Divo stands out with a yield of 42.3 t/ha, Malin white – 39.8 t/ha, and Legend – 37.1 t/ ha. The most favourable weather and climatic conditions for the production of potato tubers were for the Divo 2011 variety with a yield of 45.9 t/ha and 2013 – 45.1 t/ha. For the Legenda variety 2016, the yield of potato tubers is 40.6 t/ha and 2017 – 43.2 t/ha. Malin White 2013 is 41.4 t/ha and 2017 42.1 t/ha. The average varieties of potatoes showed a slightly lower yield on average over the years of research. However, among the varieties is allocated Nadiyna – 40.3 t/ha, Slovyanka – 37.2 t/ ha and Vera 33.8 t/ha. Among the years, the most high-yielding for the Vera variety was 2016 with a yield of 36.6 t/ha and 2017 year – 37.8 t/ha. Varieties Slovyanka and Nadiyna 2011 and 2012 with yields of 42.6 and 44.3 t/ha and 46.5 and 45.3 t/ha, respectively. Characterizing the yield of potato tubers of medium-late varieties over the years of research, there was a decrease in this indicator compared with medium-early and middle-aged varieties. However, the high yield of the varieties of Dar is allocated – 40.0 t/ha, Alladin – 33.6 t/ha and Oxamit 31.3 t/ha. Among the years, the most favourable ones were: for Oxamit and Alladin – 2011 – 33.5 and 36.5 t/ha, and 2017 – 34.1 and 36.4 t/ha, respectively. Favourable years for harvesting varieties were 2011 and 2012 with yields of 45.7 and 45.8 t/ha. Thus, the highest yield of potato tubers on average over the years of studies of medium-early varieties of 41.2-43.3 t / ha were provided by weather conditions of 2011 and 2017 years, medium-ripe varieties 41.0-41.1 - 2012 and 2011, medium- late 37,6-38,5 t / ha - 2012 and 2011, respectively.


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