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Accumulation of biologically fixed nitrogen by legumes cultivated as cover crops in Switzerland
- Büchi, Lucie, Gebhard, Claude-Alain, Liebisch, Frank, Sinaj, Sokrat, Ramseier, Hans, Charles, Raphaël
- Plant and soil 2015 v.393 no.1-2 pp. 163-175
- Lathyrus sativus, Pisum sativum, Vicia faba, Vicia sativa, Vicia villosa, agroecosystems, biomass production, cover crops, crop rotation, field experimentation, legumes, nitrogen, nitrogen content, nitrogen fixation, soil, stable isotopes, Switzerland
- AIMS: Biological nitrogen fixation by legumes is expected to play a greater role in future cropping systems. Our study evaluated 19 legume species grown as cover crops in Swiss agroecosystems. METHODS: Two field experiments were set up to monitor the biomass production and nitrogen content of 19 legumes and two non-legumes. The proportion of nitrogen derived from atmospheric N₂ (%Ndfa) was assessed using the ¹⁵N natural abundance method. In parallel, a pot experiment was set up to determine the species-specific B values necessary to apply this method. RESULTS: Some species produced an important amount of biomass in 3 months, up to 6.86 t/ha for Vicia faba. Five species, Lathyrus sativus, Pisum sativum, Vicia sativa, Vicia villosa, and V. faba, acquired more than 100 kg/ha of N through biological fixation. Important amounts of nitrogen were also derived from the soil. %Ndfa values showed high variability between and within species, ranging from 0 % to almost 100 %. CONCLUSIONS: Some legumes showed high N accumulation even in a short growing period, and could play an important role in fixing renewable nitrogen in crop rotation.