scholarly journals Impacts of management on leaching of nitrate from pastures

1990 ◽  
pp. 207-210
Author(s):  
J.L. Brock ◽  
P.R. Ball ◽  
R.A. Carran
Keyword(s):  
Nitrate Leaching ◽  
Grazing Management ◽  
Quality Factors ◽  
Pasture Management ◽  
N Losses ◽  
Animal Products ◽  
Total N ◽  
Herbage Quality ◽  
Ammonia Volatilisation ◽  
Management Approaches

Clover-based grasslands as used in New Zealand, while considered "clean" relative to grasslands farmed intensively with fertiliser nitrogen (N), are nevertheless polluting. Recent measurements of nitrate-N down the soil profile below heavily stocked (22.5 ee/ha) pastures grazed by sheep, have shown that leaching losses under set stocking are 2-3 times those from rotational grazing (37 vs 16 kg N/ha/yr). As the input of N, its storage, and outgoings in animal products are similar in both systems, this indicates that considerably more urinary N is being lost to the aerial environment from rotationally grazed pastures, with nitrate leaching being the main avenue of loss under set stocking. Differences in sward structure are suggested as the major factor. Lower nitrate leaching from cocksfoot vs ryegrass-based pastures are thought to be associated with lower herbage quality factors reducing urinary N formation. While grazing management will not greatly influence total N losses to the environrnent, it can mfluence the avenues by which N enters the wider environment. Aquatically sensitive catchments may be better protected from leaching of nitrate by modification of the grazing management approaches. Keywords pasture management, nitrate leaching, ammonia volatilisation, pasture structure, herbage quality, groundwater pollution

A review of nitrogen losses due to leaching and surface runoff under intensive pasture management in Australia

Soil Research ◽  
2014 ◽  
Vol 52 (7) ◽  
pp. 621 ◽  
Author(s):  
Lucy L. Burkitt
Keyword(s):  
New Zealand ◽  
Nitrate Leaching ◽  
Surface Runoff ◽  
Dairy Industry ◽  
Farming Systems ◽  
Dairy Farms ◽  
Future Research ◽  
Pasture Management ◽  
N Losses ◽  
Pasture Production

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.

Interacting abiotic, biochemical and management factors explain soil organic carbon in Pyrenean grasslands

2020 ◽  
Author(s):  
Antonio Rodríguez ◽  
Rosa Maria Canals ◽  
Josefina Plaixats ◽  
Elena Albanell ◽  
Haifa Debouk ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Large Scale ◽  
Plant Biomass ◽  
Spatial Scales ◽  
Grazing Management ◽  
Quality Factors ◽  
Wide Range ◽  
Herbage Quality ◽  
Management Factors

&lt;p&gt;Grasslands are one of the major sinks of terrestrial soil organic carbon (SOC). Understanding how environmental and management factors drive SOC is challenging because there are scale-dependent effects, and large scale drivers affecting SOC both directly and through drivers working at fine spatial scales. Here we address how regional and landscape factors, and grazing management, soil properties and nutrients, and herbage quality factors affect SOC in mountain grasslands in the Pyrenees. Taking advantage of the high variety of environmental heterogeneity in the Pyrenees, we fitted a set of models with explicative purposes including variables that comprise a wide range of environmental and management conditions. We found that temperature seasonality (MMT) was the most important abiotic driver of SOC in our study. MMT was positively related to SOC but only under certain conditions: exposed hillsides, steep slopes and relatively highly grazed areas. High MMT conditions probably are more favourable for plant biomass production, but landscape and grazing management factors buffer the conversion of this biomass into SOC. Concerning biochemical SOC predictors, we obtained some unexpected interaction effects between grazer type, soil nutrients and herbage quality. Soil N was a crucial factor modulated by effects of livestock species and neutral-detergent fibre content of vegetation. Herbage recalcitrance effects varied depending on grazer species. These results highlight the need to expand knowledge about grassland SOC drivers under different environmental and management conditions.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

White clover or nitrogen fertiliser for dairying under nitrate leaching limits?

2020 ◽  
Vol 60 (1) ◽  
pp. 78 ◽  
Author(s):  
David Chapman ◽  
Ina Pinxterhuis ◽  
Stewart Ledgard ◽  
Tony Parsons
Keyword(s):  
Nitrate Leaching ◽  
Soluble Sugar ◽  
Grass Species ◽  
N Leaching ◽  
N Fixation ◽  
N Losses ◽  
Total N ◽  
Mixed Grass ◽  
Dairy Systems ◽  
N Use

As the pressure intensifies to reduce nitrogen (N) losses to the environment from pasture-based dairy systems, interest in reducing N-fertiliser inputs and returning to grass–clover mixtures, where more N for pasture growth is supplied by biological N fixation (BNF), have been revived. However, the following question then arises: is BNF fundamentally different from fertiliser N with respect to N losses, especially nitrate-N leaching risk? The present paper addresses this question by reviewing empirical evidence in the context of N-cycling processes and the efficiency of N use for herbage production. Nitrate leaching data from studies comparing different sward treatments at the same level of total N inputs (fertiliser plus BNF) provide no evidence to suggest that leaching differs when N is supplied solely by fixation in mixtures, by fixation plus fertiliser in mixtures, or solely as a fertiliser to grass monoculture. Increasing clover content in mixed grass–clover pastures is likely to increase N leaching due to a lower ratio of soluble sugar and starch to N in herbage than the common companion grass species perennial ryegrass, and, therefore, a higher partitioning of N eaten to urine. Counteracting this effect, mixed grass–clover pastures may offer some potential for increasing N-use efficiency and reducing the whole-farm N surplus compared with grass-dominant pasture receiving high rates of N fertiliser. While there are undeniable benefits for the productivity of dairy systems from maintaining strong grass–clover mixtures, it is the total amount of N entering the system, rather than the form of N (BNF or fertiliser), that influences nitrate leaching rates.

scholarly journals Very Low Nitrogen Leaching in Grazed Ley-Arable-Systems in Northwest Europe

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2155
Author(s):  
Hendrik P. J. Smit ◽  
Thorsten Reinsch ◽  
Christof Kluß ◽  
Ralf Loges ◽  
Friedhelm Taube
Keyword(s):  
Nitrate Leaching ◽  
C Sequestration ◽  
Winter Precipitation ◽  
Catch Crop ◽  
Pasture Management ◽  
N Losses ◽  
Leaching Losses ◽  
Soil C ◽  
Permanent Grassland ◽  
Northwest Europe

High input dairy farms that are located on sandy soils in northwest Europe are predisposed to substantial nitrate leaching during a surplus of winter precipitation. Leys within integrated crop-livestock systems play an important role in soil fertility, soil C sequestration and soil N mineralization potentials. Therefore, leys are a feasible option that can be utilized to reduce local N losses to the environment, especially following maize grown for silage. We hypothesize that grass-clover leys ensure low nitrate leaching losses even when grazed intensively. The extent to which NO3-leaching occurred across seven different pasture management systems in terms of their sward composition, cutting, grazing, fertilization and combinations thereof was investigated in integrated animal-crop grazing systems over three winter periods (2017/2018, 2018/2019 and 2019/2020). The observed grazed systems were comprised of cut-used- and grazed grass-clover swards (0, 1 and 2 years after establishment following cereals), a catch crop grazed late in the year as well as a cut-used permanent grassland for comparison. Overall, all treatments resulted in nitrate leaching losses that did not exceed the WHO-threshold (25 mg nitrate/L). The highest level of NO3-leaching was observed in the catch crop system and the lowest in cut-used permanent grassland, with NO3-N losses of 19.6 ± 5.3 and 2.1 ± 0.3 kg NO3-N ha−1 year−1. Annual herbage yields were in the range of 0.9 to 12.4 t DM ha−1 and nitrogen yields varied between 181 ± 51 and 228 ± 66 kg N ha−1 during the study period. The highest herbage-N-yields were observed from the 1- and 2-year-old grass-clover leys. The highest N-field-balance was observed for the grazed leys and the lowest for the cut-used permanent grassland. However, no correlation was found between the highly positive field-N-balance and the amount of NO3-leached. This indicates a high N carry-over from grass-clover swards to the subsequent cash crop unit instead of increasing the risk of groundwater contamination from grazed leys in integrated animal crop-systems and underlines the eco-efficiency of dairy farming based on grazed ley systems.

scholarly journals NMR Metabolite Profiles in Male Meat-Eaters, Fish-Eaters, Vegetarians and Vegans, and Comparison with MS Metabolite Profiles

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 121
Author(s):  
Julie A. Schmidt ◽  
Georgina K. Fensom ◽  
Sabina Rinaldi ◽  
Augustin Scalbert ◽  
Marc J. Gunter ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Clinical Chemistry ◽  
Saturated Fatty Acids ◽  
Density Lipoprotein ◽  
Diet Group ◽  
Gas Liquid Chromatography ◽  
Very Low Density Lipoproteins ◽  
Animal Products ◽  
Total N ◽  
Metabolite Profiles

Metabolomics may help to elucidate mechanisms underlying diet-disease relationships and identify novel risk factors for disease. To inform the design and interpretation of such research, evidence on diet-metabolite associations and cross-assay comparisons is needed. We aimed to compare nuclear magnetic resonance (NMR) metabolite profiles between meat-eaters, fish-eaters, vegetarians and vegans, and to compare NMR measurements to those from mass spectrometry (MS), clinical chemistry and capillary gas-liquid chromatography (GC). We quantified 207 serum NMR metabolite measures in 286 male participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford cohort. Using univariate and multivariate analyses, we found that metabolite profiles varied by diet group, especially for vegans; the main differences compared to meat-eaters were lower levels of docosahexaenoic acid, total n-3 and saturated fatty acids, cholesterol and triglycerides in very-low-density lipoproteins, various lipid factions in high-density lipoprotein, sphingomyelins, tyrosine and creatinine, and higher levels of linoleic acid, total n-6, polyunsaturated fatty acids and alanine. Levels in fish-eaters and vegetarians differed by metabolite measure. Concentrations of 13 metabolites measured using both NMR and MS, clinical chemistry or GC were mostly similar. In summary, vegans’ metabolite profiles were markedly different to those of men consuming animal products. The studied metabolomics platforms are complementary, with limited overlap between metabolite classes.

scholarly journals Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1214
Author(s):  
Hendrik P. J. Smit ◽  
Thorsten Reinsch ◽  
Pieter A. Swanepoel ◽  
Ralf Loges ◽  
Christof Kluß ◽  
...  
Keyword(s):  
South Africa ◽  
N Fertilization ◽  
Yield Response ◽  
N2o Emissions ◽  
Pasture Management ◽  
N Losses ◽  
Enteric Fermentation ◽  
Soil C ◽  
Grazed Pastures ◽  
Soil C And N

Nitrogen fertilization, irrigation and concentrate feeding are important factors in rotational pasture management for dairy farms in South Africa. The extent to which these factors affect environmental efficiency is subject to current and intense debate among scientists. A three-year field study was conducted to investigate the yield response of different N-fertilizer treatments (0 (N0), 220 (N20), 440 (N40), 660 (N60) and 880 (N80) kg N ha−1 year−1) on grazed pastures and to calculate the carbon footprint (CF) of milk produced. Excessive N-fertilization (N60 and N80) did not increase herbage dry matter and energy yields from pastures. However, N80 indicated the highest N-yield but at the same time also the highest N surpluses at field level. A maximum fertilizer rate of 220 kg ha−1 year−1 (in addition to excreted N from grazing animals) appears sufficient to ensure adequate herbage yields (~20 t DM ha−1 year−1) with a slightly positive field-N-balance. This amount will prevent the depletion of soil C and N, with low N losses to the environment, where adequate milk yields of ~17 t ECM ha−1 with a low CF (~1.3 kg CO2 kg ECM−1) are reached. Methane from enteric fermentation (~49% ± 3.3) and N2O (~16% ± 3.2) emissions from irrigated pastures were the main contributors to the CF. A further CF reduction can be achieved by improved N-fertilization planning, low emission irrigation techniques and strategies to limit N2O emissions from pasture soils in South Africa.

scholarly journals Effect of Soil Management on Erosion in Mountain Vineyards (N-W Italy)

2021 ◽  
Vol 13 (4) ◽  
pp. 1991
Author(s):  
Silvia Stanchi ◽  
Odoardo Zecca ◽  
Csilla Hudek ◽  
Emanuele Pintaldi ◽  
Davide Viglietti ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Management Practices ◽  
Soil Management ◽  
Buffer Strips ◽  
Total N ◽  
Organic C ◽  
Erosion Rates ◽  
Soil Ecosystem Services ◽  
Erosion Mitigation ◽  
Management Approaches

We studied the effects of three soil management approaches (permanent grassing, chemical weeding, and buffer strips), and the additional impact of tractor passage on soil erosion in a sloping vineyard located in the inner part of Aosta Valley (N-W Italian Alps). The vineyard rows were equipped with a sediment collection system with channels and barrel tanks. A total of 12 events with sediment production were observed across 6 years, and the collected sediments were weighted and analyzed. Average erosion rates ranged from negligible (mainly in grassed rows) to 1.1 t ha−1 per event (after weeding). The most erosive event occurred in July 2015, with a total rainfall of 32.2 mm, of which 20.1 were recorded in 1 h. Despite the limited number of erosive events observed, and the low measured erosion rates, permanent grassing reduced soil erosion considerably with respect to weeding; buffering had a comparable effect to grassing. The tractor passage, independent of the soil management approaches adopted, visibly accelerated the erosion process. The collected sediments were highly enriched in organic C, total N, and fine size fractions, indicating a potential loss of fertility over time. Despite the measured erosion rates being low over the experiment’s duration, more severe events are well documented in the recent past, and the number of intense storms is likely to increase due to climate change. Thus, the potential effects of erosion in the medium and long term need to be limited to a minimum rate of soil loss. Our experiment helped to compare soil losses by erosion under different soil management practices, including permanent grassing, i.e., a nature-based erosion mitigation measure. The results of the research can provide useful indications for planners and practitioners in similar regions, for sustainable, cross-sectoral soil management, and the enhancement of soil ecosystem services.

scholarly journals The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Field Experiments ◽  
N2o Emission ◽  
N2o Emissions ◽  
N Loss ◽  
N Losses ◽  
Total N ◽  
Tropical Regions ◽  
The Impact

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.

scholarly journals Processes of ammonia air-surface exchange in a fertilized <i>Zea mays</i> canopy

2012 ◽  
Vol 9 (6) ◽  
pp. 7893-7941 ◽  
Author(s):  
J. T. Walker ◽  
M. R. Jones ◽  
J. O. Bash ◽  
L. Myles ◽  
T. Meyers ◽  
...  
Keyword(s):  
Zea Mays ◽  
Temporal Dynamics ◽  
Daily Maximum ◽  
N Losses ◽  
Surface Exchange ◽  
Total N ◽  
Soil Emissions ◽  
Source Sink ◽  
Resistance Modeling ◽  
Process Level

Abstract. Recent incorporation of coupled soil biogeochemical and bi-directional NH3 air-surface exchange algorithms into regional air quality models holds promise for further reducing uncertainty in estimates of NH3 emissions from fertilized soils. While this represents a significant advancement over previous approaches, the evaluation and improvement of such modeling systems for fertilized crops requires process level field measurements over extended periods of time that capture the range of soil, vegetation, and atmospheric conditions that drive short term (i.e., post fertilization) and total growing seasonNH3 fluxes. This study examines the processes of NH3 air-surface exchange in a fertilized corn (Zea mays) canopy over the majority of a growing season to characterize soil emissions after fertilization and investigate soil-canopy interactions. Micrometeorological flux measurements above the canopy, measurements of soil, leaf apoplast and dew/guttation chemistry, and a combination of in-canopy measurements, inverse source/sink, and resistance modeling were employed. Over a period of approximately 10 weeks following fertilization, daily mean and median net canopy-scale fluxes yielded cumulative total N losses of 8.4% and 6.1%, respectively, of the 134 kg N ha−1 surface applied to the soil as urea ammonium nitrate (UAN). During the first month after fertilization, daily mean emission fluxes were positively correlated with soil temperature and soil volumetric water. Diurnally, maximum hourly average fluxes of ≈700 ng N m−2 s−1 occurred near mid-day, coincident with the daily maximum in friction velocity. Net emission was still observed 5 to 10 weeks after fertilization, although mid-day peak fluxes had declined to ≈125 ng N m−2 s−1 A key finding of the surface chemistry measurements was the observation of high pH (7.0 – 8.5) in leaf dew/guttation, which reduced the ability of the canopy to recapture soil emissions during wet periods. In-canopy measurements near peak LAI indicated that the concentration of NH3 just above the soil surface was highly positively correlated with soil volumetric water, which likely reflects the influence of soil moisture on resistance to gaseous diffusion through the soil profile and hydrolysis of remaining urea. Inverse source/sink and resistance modeling indicated that the canopy recaptured ≈73% of soil emissions near peak LAI. Stomatal uptake may account for 12–34% of total uptake by foliage during the day compared to 66–88% deposited to the cuticle. Future process-level \\NH3 studies in fertilized cropping systems should focus on the temporal dynamics of net emission to the atmosphere from fertilization to peak LAI and improvement of soil and cuticular resistance parameterizations.

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