Effect of long-term fertilizer application on C-sequestration and sustainable yields of finger millet and groundnut grown under rotation in semi-arid Alfisols

Abstract

ABSTRACTBased on a long-term finger millet-groundnut rotation study conducted for 24-years during 1992–2015 under Alfisols at Bangalore, organic and inorganic fertilizer effects on soil organic carbon (SOC) sequestration and sustainability of yield were assessed. Field experiments were conducted with T1:Control; T2:FYM@ 10t ha−1; T3:FYM@ 10t ha−1 + 50% NPK; T4:FYM@ 10t ha−1 + 100% NPK, and T5:100% recommended NPK in same plot every year. T5 comprised of 50 kg N, 50 kg P2O5 and 25 kg K2O ha−1 for finger millet and 25 kg N, 50 kg P2O5 and 25 kg K2O ha−1 for groundnut. Sustainability yield index of treatments was assessed using measurements made on variability of yield over years. The amount of carbon sequestered was assessed to identify a superior treatment for improving soil quality. Balanced use of 100% NPK+ FYM for maintenance of SOC at antecedent level with biomass-C of 1.62 Mg C ha−1 year−1 was feasible for sustaining production under semi-arid Alfisols.