Leaching and crop uptake of N, P and K from organic and conventional cropping systems on a clay soil

Abstract

In this study, three types of cropping systems with different nutrient management strategies were studied on a clay soil with the aim of comparing leaching of N, P and K and obtaining knowledge on nutrient budgets. A conventional cropping system with cereals and application of mineral fertilizers (CON) was compared with two organic cropping systems, one without animal manure in which green manure crops were used for N supply (OGM) and one where animal manure (cattle slurry) was applied (OAM). Leaching and crop uptake of N, P and K, and soil mineral N were measured in pipe-drained plots over a 6-year period.The mean annual leaching loads of N were moderate and did not differ significantly (P > 0.05) between treatments; 13 kg N ha )1 in CON, 11 kg N ha )1 in OGM and 7.4 kg N ha )1 in OAM. Average annual P leaching showed greater variation than N leaching and was significantly greater in OGM (0.81 kg ha )1 year )1 ) than in CON (0.36 kg ha )1 ) and OAM (0.41 kg ha )1 ). For all cropping systems, removal in harvested crops was the most important export of nutrients from the field and constituted between 80 and 94% of total N outputs (harvested and leached N). Yields of cereals in the organic systems were considerably less (15-50%) than in the CON system, leading to a less efficient use of N than in the conventional system.

Crop yield, root growth, and nutrient dynamics in a conventional and three organic cropping systems with different levels of external inputs and N re-cycling through fertility building crops

“…Leifert et al, 2007;Eyre et al, 2009), where comparisons were made not only between organic and conventional systems, but between all combinations of organic vs. conventional plant protection, nutrient management and rotations optimized for organic or conventional production, in order to investigate which of these factors are primarily responsible for differences in productivity, environmental effects or product quality. Other studies of organic cereal rotations have focused on the use of animal vs. green manures (Torstensson et al, 2006;Aronsson et al, 2007;Doltra et al, 2011). However, though these experiments were very different in their approach, they were all aimed to investigate methods that were already in common use in organic production.…”

“…Birkhofer et al, 2008;Aronsson et al, 2007) or produce higher quality food than conventional methods (e.g. Dangour et al, 2009).…”

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

“…This was also shown in a study carried out on a clay soil in southwest Sweden, in which conventional and organic systems were compared (Aronsson et al, 2007). It is also obvious from these studies that N leaching per hectare is not reduced when organic manures are used instead of inorganic N fertilisers.…”

“…Irrespective of the organic N source used in organic crop production, several studies have shown that they provide the crop with less N than similar amounts of N applied as mineral fertiliser (e.g. Thomsen et al, 1997;Aronsson et al, 2007;Bergström and Kirchmann, 2006). Thus, a lower N use efficiency seems to be a common problem in organic cropping systems, despite the fact that N inputs tend to be lower in organic systems than in conventional.…”

“…Aronsson et al, 2007; 1999; 2000), has to be taken seriously, considering that future population growth will require more food to be produced. In this context, it is critical to increase or at least maintain yields per area without jeopardising environmental quality.…”