Nitrogen dynamics following grain legumes and subsequent catch crops and the effects on succeeding cereal crops

Abstract

The effects of faba bean, lupin, pea and oat crops, with and without an undersown grassclover mixture as a nitrogen (N) catch crop, on subsequent spring wheat followed by winter triticale crops were determined by aboveground dry matter (DM) harvests, nitrate (NO 3 ) leaching measurements and soil N balances. A 2-year lysimeter experiment was carried out on a temperate sandy loam soil. Crops were not fertilized in the experimental period and the natural 15 N abundance technique was used to determine grain legume N 2 fixation. Faba bean total aboveground DM production was significantly higher (1,300 g m -2 ) compared to lupin (950 g m -2 ), pea (850 g m -2 ) and oat (1,100 g m -2 ) independent of the catch crop strategy. Faba bean derived more than 90% of its N from N 2 fixation, which was unusually high as compared to lupin (70-75%) and pea (50-60%). No effect of preceding crop was observed on the subsequent spring wheat or winter triticale DM production. Nitrate leaching following grain legumes was significantly reduced with catch crops compared to without catch crops during autumn and winter before sowing subsequent spring wheat. Soil N balances were calculated from monitored N leaching from the lysimeters, and measured N-accumulation from the leguminous species, as N-fixation minus N removed in grains including total N accumulation belowground according to Mayer et al. (2003a). Negative soil N balances for pea, lupin and oat indicated soil N depletion, but a positive faba bean soil N balance (11 g N m -2 ) after harvest indicated that more soil mineral N may have been available for subsequent cereals. However, the plant available N may have been taken up by the grass dominated grass-clover catch crop which together with microbial N immobilization and N losses could leave limited amounts of available N for uptake by the subsequent two cereal crops.

Legume, cropping intensity, and N-fertilization effects on soil attributes and processes from an eight-year-old semiarid wheat system

“…Researchers have cautioned that legume N residue needs to be managed properly in order to increase N synchrony with crop uptake demands (Crews and Peoples 2005;Gardner and Drinkwater 2009), and to improve legume-N retention (Hauggaard-Nielsen et al 2009;Starovoytov et al 2011). Even in semiarid Saskatchewan, a 17-year old LGM (lentil)-W-W rotation led to higher NO 3 -N leaching than a F-W-W control when the N supplying capacity of the soil was underestimated (Campbell et al 2006).…”

Plant: soil interactions in temperate multi-cropping production systems

“…Although N leaching was found to decrease in pea-barley intercrops compared to sole crops, these results were not significant (Hauggaard-Nielsen et al 2001b). Positive effects have also been observed when incorporating grasses into cropping systems as catch crops or green manure leys, reducing the risk of N losses during the winter season (Hauggaard-Nielsen et al 2009;Dahlin and Stenberg 2010). However, greater N mineralisation rates were found after winter, and N taken up by catch crops may still be lost if it remineralises before the main crop can take it up (van Dam 2006).…”

The role of catch crops in the ecological intensification of spring cereals in organic farming under Nordic climate

“…In Nordic climates N leaching losses of nitrate or ammonium outside the main growing season can be effectively reduced by growing catch crops (e.g., Askegaard et al, 2005;Känkänen and Eriksson, 2007;Hauggaard-Nielsen et al, 2009a;Engström et al, 2010;Doltra et al, 2011). The N retained in catch crops can be made available for the succeeding spring cereal by timing the soil incorporation of the catch crop relative to cereal sowing to allow decomposition of the catch crop residues.…”