- Institutionen för biosystem och teknologi, Sveriges lantbruksuniversitet
Raberg, Tora Matilda; Carlsson, Georg; Jensen, Erik Steen
Recirculation of nitrogen (N) from crop residue and green-manure biomass resources may reduce the need to add new reactive N to maintain crop yield and quality. The aim of this study was to determine how different strategies for recycling residual and green-manure biomass influence yield and N concentration of the edible parts of food crops in a stockless organic cropping system. For this purpose, three biomass distribution treatments were investigated in a field experiment, based on a cropping system designed to produce both high-quality food crops and biomass resources from crop residues, cover crops and a green-manure ley. The three treatments, applied at the cropping system level, were: (1) incorporating the aboveground biomass resources in situ (IS); (2) harvesting, ensiling and redistributing the same biomass resources to the non-legume crops (biomass redistribution, BR); and (3) harvesting, ensiling and using the biomass resources as substrate for production of bio-methane via anaerobic digestion (AD) followed by distribution of the digestate as bio-fertilizer to the non-legume crops. The redistribution of ensiled (BR) and digested (AD) biomass did not increase the yield of the edible parts in winter rye (Secale cereal L.), white cabbage (Brassica oleracea L.) or red beet (Beta vulgaris L.) compared with leaving the biomass on the ground at harvest (IS). The BR treatment increased the yield of lentil intercropped with oat, compared with IS treatment in one of the two studied years. The total biomass yield of the cover crop following winter rye was significantly higher in the BR treatment than in IS in both years. The legume proportion in the green-manure ley was significantly higher in the AD and BR treatments as compared with IS in one of the experimental years. This study showed that strategic biomass redistribution has the potential to enhance biomass productivity while maintaining food crop yields, thereby enhancing whole system productivity. Biomass redistribution systems both with and without biogas digestion offer a new strategy for the development of multifunctional arable cropping systems that rely on internal nutrient cycling.
anaerobic digestion; cover crop; digestate; diversity; green-manure biomass; intercropping; agronomy; horticulture; arable; stockless; strategic recycling
Renewable Agriculture and Food Systems
2019, Volym: 34, nummer: 1, sidor: 20-32
SDG12 Responsible consumption and production