Long-term conservation agriculture increases nitrogen use efficiency by crops, land equivalent ratio and soil carbon stock in a subtropical rice-based cropping system

Conservation Agriculture (CA) is still a relatively new approach for intensively cultivated (3 crops yr -1 ) rice-based cropping systems that produce high crop yield and amounts of residues annually. With the recent development transplanting rice into tilled strips on non-puddled soil, CA could become feasible patterns. However, effect increased retention response to nitrogen (N) fertilization rate in strip with transplanted other grown annual rotation yet be determined. For nine years, we have examined effects soil disturbance levels - tillage (ST) conventional (CT), two residue –15% by height (low residue, LR) 30% (high HR) five N rates (60%, 80%, 100%, 120%, 140% recommended fertilizer doses (RFD)) rice-wheat-mungbean sequence. The 100% RFD was 75, 100 20 kg ha rice, wheat, mungbean, respectively. Rice yields were comparable between up year-6, wheat year-3 but mungbean markedly ST from year-1; however, land equivalent ratio year-1, principally because higher yield. Introduction 26% relative CT, use efficiency partial factor productivity. Nitrogen demand maximum about 10% 5% decreased wheat. Although had system due than requirement declined by50–90% when same goal considered as CT. organic carbon stock (0–15 cm) after 8 years 21.5 30.5 t plus retention. Annual gross margin 57% over CT practice HR LR In conclusion, 9 practicing under tillage, efficiency, grain yield, while minimally. • Strip profitability. Adoption efficiency. required more produced SOC years.