Nitrate leaching from organic farms and conventional farms following best practice

Stopes, C.; Lord, E. I.; Philipps, Lois; Woodward, Lawrence

doi:10.1111/j.1475-2743.2002.tb00267.x

Cited by 56 publications

(44 citation statements)

References 15 publications

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“…This might have been a consequence of the lower than average rainfall during the trial period resulting in less drainage than expected for this geographical area. However, in accordance with our results, Stopes et al (2002) reported similar or smaller losses from organically managed sites compared to conventional systems when under similar cropping. In addition, Drinkwater et al (1998) and Bergström & Kirchmann (2004) showed that the inclusion of green manure crops in the cropping sequence can improve soil N retention and, consequently, reduce losses.…”

Section: Effect Of Past and Current Management On Mineral N Leachingsupporting

confidence: 92%

“…in this study, the amounts of annual n leaching observed (1.3-20 kg ha -1 ) are comparable to those reported in other studies (di & Cameron 2002b;Stopes et al 2002), indicating that addition of n in mineral form had no effect on the leaching patterns nor did incorporation of a leguminous green manure drastically increase mineral N losses. This might have been a consequence of the lower than average rainfall during the trial period resulting in less drainage than expected for this geographical area.…”

Section: Effect Of Past and Current Management On Mineral N Leachingsupporting

confidence: 89%

“…Several studies have shown that organic farming practices can reduce nitrate leaching (dalgaard et al 1998; e.g., Stolze et al 2000;Stopes et al 2002), whereas others stress that mineral n losses can be equal or higher from organic farms. application of animal manures or incorporation of green manures can result in N flushes owing to sudden mineralisation of the organic material (Eriksen et al 1999;Shepherd et al 2003).…”

Section: Effect Of Past and Current Management On Mineral N Leachingmentioning

confidence: 99%

See 2 more Smart Citations

Effects of past and current management practices on crop yield and nitrogen leaching—a comparison of organic and conventional cropping systems

Stark¹,

Condron

Stewart

et al. 2006

New Zealand Journal of Crop and Horticultural Science

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Farming practices can have significant effects on important soil processes, including nitrogen (N) dynamics and nitrate leaching. A lysimeter experiment was conducted to determine differences in N leaching resulting from past and current crop management practices. Intact monolith lysimeters (50cm diam. × 70cm deep) were taken from sites of the same soil type that had either been under long-term organic or conventional crop management. These were then managed according to established organic and conventional practices over 2½ years using the same crop rotation ( manure (Lupinus angustifolius L.)) and two fertiliser regimes, resulting in four treatments based on soil management history and current fertilisation strategy. Dry matter yield of each crop was determined after harvest and leachates were collected after significant rainfall events and analysed for total mineral N concentrations. Mineral fertilisation had a clear positive effect on yields of the first crop, whereas there were no considerable differences between treatments for the last crop owing to a significant positive effect of green manure incorporation on yields. Although there was a trend of lower mineral N leaching from organically fertilised soils (organic management: 24.2 kg N ha -1 ; conventional management: 28.6), differences in N losses were not statistically significant between treatments. This shows that under the experimental conditions, leaching losses and crop yields were more strongly influenced by crop rotation and green manuring than by the presence or absence of mineral fertilisation. Overall, the study highlights the benefits of including a green manure in the crop rotation of any farming system.

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Section: Effect Of Past and Current Management On Mineral N Leachingsupporting

confidence: 92%

Section: Effect Of Past and Current Management On Mineral N Leachingsupporting

confidence: 89%

Section: Effect Of Past and Current Management On Mineral N Leachingmentioning

confidence: 99%

See 1 more Smart Citation

Effects of past and current management practices on crop yield and nitrogen leaching—a comparison of organic and conventional cropping systems

Stark¹,

Condron

Stewart

et al. 2006

New Zealand Journal of Crop and Horticultural Science

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“…Clearly the optimal use of nitrogenous fertilizers will reduce environmental pollution, however there is little evidence that nitrate leaching differs between organic and conventional production systems when following best practice (Stopes et al 2002;Trewavas 2002). Our results suggest that at the level of gene expression, wheat grain from plants supplied with either organic or inorganic nitrogen is reproducibly different.…”

Section: Resultsmentioning

confidence: 99%

Markedly different gene expression in wheat grown with organic or inorganic fertilizer

Hawkesford

Barraclough

et al. 2005

Proc. R. Soc. B.

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Nitrogen is the major determinant of crop yield and quality and the precise management of nitrogen fertilizer is an important issue for farmers and environmentalists. Despite this, little is known at the level of gene expression about the response of field crops to different amounts and forms of nitrogen fertilizer. Here we use expressed sequence tag (EST)-based wheat microarrays in combination with the oldest continuously running agricultural experiment in the world to show that gene expression is significantly influenced by the amount and form of nitrogenous fertilizer. In the Broadbalk winter wheat experiment at Rothamsted in the United Kingdom and at three other diverse test sites, we show that specific genes have surprisingly different expression levels in the grain endosperm when nitrogen is supplied either in an organic or an inorganic form. Many of the genes showing differential expression are known to participate in nitrogen metabolism and storage protein synthesis. However, others are of unknown function and therefore represent new leads for future investigation. Our observations show that specific gene expression is diagnostic for use of organic sources of nitrogen fertilizer and may therefore have useful applications in defining the differences between organically and conventionally grown wheat.

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“…It is also quite common to base leaching estimates on nutrient concentrations obtained from soil water samples in porous suction probes and water flux calculations with mathematical simulation models (e.g. Stopes et al, 2002), which also generates uncertain load estimates. Another limitation of a number of leaching studies is that leaching loads are only related to the cropping area, disregarding yield differences (Corré et al, 2003;Kirchmann and Bergström, 2001), which can lead to erroneous conclusions about the environmental benefits of organic systems (e.g.…”

Section: Introductionmentioning

confidence: 99%

Use Efficiency and Leaching of Nutrients in Organic and Conventional Cropping Systems in Sweden

Bergström

Kirchmann

Aronsson

et al.

Organic Crop Production – Ambitions and Limitations

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In the past few years, organic farming has been proposed as a possible way of reducing N leaching from agricultural soils and improving the use efficiency of plant nutrients. This is, to a large extent, considered to be attributed to the fact that synthetic fertilisers are not allowed in such systems and the N inputs mainly originate in various types of organic manures. In this overview, results from a number of Swedish field studies are presented in which crop yields, nutrient-use efficiencies and leaching in organic and conventional systems are evaluated. Some studies were conducted in lysimeters and others in large tile-drained field plots. In two lysimeter experiments, leaching of N derived from either poultry manure or red clover (Trifolium pratense L.) green manure were compared with fertiliser N, all labeled with 15-N. In the lysimeters on which poultry manure was applied, 32% of N applied leached during three years, whereas only about 3% leached in ammonium nitrate fertilised lysimeters. In plots on a sandy soil, annual N leaching loads averaged over the whole 6-yr crop rotation reached 39 kg N ha -1 in the organic rotations and 25 kg N ha -1 in the conventional rotation. Phosphorusleaching loads were overall small in all systems, whereas K leaching was highest in the conventional rotation (i.e., on average, 27 kg ha -1 yr -1 ). In terms of crop yields, they were reduced by 20 to 80% in the organic rotations compared to the same crops in the conventional rotations. This was explained in terms of N deficiency, weed competition, and infestation of crop diseases in the organic systems. These results suggest that organic crop production uses agricultural soils less efficiently, with no benefit for water quality.

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Nitrate leaching from organic farms and conventional farms following best practice

Cited by 56 publications

References 15 publications

Effects of past and current management practices on crop yield and nitrogen leaching—a comparison of organic and conventional cropping systems

Effects of past and current management practices on crop yield and nitrogen leaching—a comparison of organic and conventional cropping systems

Markedly different gene expression in wheat grown with organic or inorganic fertilizer

Use Efficiency and Leaching of Nutrients in Organic and Conventional Cropping Systems in Sweden

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