Incorporation of biochar and legumes into the summer gap: improving productivity of cereal-based cropping systems in Pakistan

Abstract

Biochar can improve soil quality, increase crop production and sequester C in agricultural systems; however, this now needs critical evaluation in a sustainable agricultural context. In Pakistan, there is a gap in cereal-based wheat-maize-wheat cropping systems that lasts between 70-80 days. This "summer gap" can be used for growing short duration legume crops, which can provide valuable grain, fodder, or green manure and can provide a sustainable input of N into agricultural systems. We have used a field-based study to determine the effect of biochar application to an alkaline, nutrient poor, soil on the productivity of legume crops grown during the summer gap. Overall, biochar application (50 t ha-1) increased the productivity and yield of cowpea, mungbean and Sesbania over two cropping seasons compared to unamended non-biochar controls. The integration of biochar and legumes could be a useful strategy for improving the overall farm productivity of cereal-based cropping systems in Pakistan, by delivering a sustainable input of N to soil and providing increased yields from this additional summer gap crop.