Effect of catch crops on N dynamics and following crops in organic farming

Abstract

Green manure catch crops promote the sustainability of agricultural systems by reducing soil erodibility and by nutrient uptake and transfer to the following main crops. This effect efficiently reduces the risk of nitrate leaching. Biological nitrogen fixation by legume catch crops is an additional benefit, mainly in organic farming. Such crops may, however, reduce nitrogen uptake from the soil and increase nitrate leaching. Additionally, under drought conditions, their extra water consumption may outweigh the beneficial effects. To determine the best catch crop management in stockless organic farming under dry, Pannonian site conditions in eastern Austria, four treatments were compared in 2002 and 2004: (1) legumes: field pea, common vetch and chickling vetch, (2) non-legumes: phacelia, oil radish and turnip, (3) a legume and non-legume mixture (all mentioned components), and (4) a bare fallow control. Our results show that catch crop biomass and N yield, biological N fixation, and crop N uptake from the soil were about 4 times higher under moderately dry conditions in 2002 than under drought conditions in summer and autumn 2004. In 2002, the legume/non-legume mixture had the highest biomass and N yield and the highest biological N fixation. Both the legume/non-legume mixture and the non-legumes were more efficient than legumes in N uptake from the soil (+32 kg N ha −1 ); and in reducing both soil inorganic N contents by -45 kg N ha −1 and nitrate concentrations in soil solution by -20 mg N L −1 . These findings show that the legume/non-legume mixture combined the positive effects of non-legumes and legumes. In 2004, catch crop effects did not differ except for their above-mentioned effect on inorganic N contents. The only pre-crop effect was that of legumes compared with non-legumes on spring barley grain dry matter of +0.6 Mg DM ha −1 and grain N yield of +17 kg N ha −1 in 2005. The water consumption of catch crops never adversely affected the following crops. green manure / biological nitrogen fixation / nitrogen conservation / drought / legume catch crop

Yield and soil coverage of catch crops and their impact on the yield of spring barley

“…In that year, with the exception of Panicum miliaceum L., a statistically significant difference in the yields of spring barley after catch crops and control variant was recorded. Reduction of spring barley yield was extraordinary; after Sinapis alba L. was as much as 44% down when compared to the control Rinnofner et al (2008). Only in extreme years, a very low rainfall in the winter and during the growth and development of spring barley may reduce its yield after grown catch crops, confirming the assertion of Bodner (2013).…”

Improving Nitrogen Use Efficiency in Crops for Sustainable Agriculture

“…When cover crops are planted to reduce nutrient leaching (N in particular) following a main crop, they are often termed "catch crops." [75,76]. Moreover, growing green manures on site is a way to prevent the often inhibitive handling and transportation costs of other organic inputs [69].…”

“…Conditions that encourage good N production include getting a good stand, optimum soil nutrient levels and soil pH, good nodulation, and adequate soil moisture. The portion of green-manure N available to a following crop is usually about 40% to 60% of the total amount contained in the legume [76]. Interestingly, it has been demonstrated that leguminous cover crops were also able to replace 60% of the chemical N fertilization for cotton production, although the quantity of available N derived from the cover crop was not synchronized with the requirements of the cotton plant [89].…”

Evaluation of Vicia sativa L. as green manure: Case study of genotype and plant density influence on N availability

“…Common vetch is desirable as green manure mainly for the ability to form vigorous root system that develops nodules at early stages and fixes atmospheric N into the soil (Rinnofner et al, 2008;Vlachostergios et al, 2011). Although a lot of research has been carried out on vetch production (Tuna and Oraka, 2007) there is little information about the contribution of Vicia sativa as green manure.…”