Productivity, soil health, and carbon management index of soybean-wheat cropping system under double zero-tillage and natural-farming based organic nutrient management in north-Indian plains

Conservation-agriculture and organic-farming are two sustainable-agriculture approaches to ensure food security and environmental-sustainability. Hence, a field study assessed the productivity, soil-health and carbon-dynamics of soybean-wheat cropping system (SWCS) under four tillage and residue-management practices (TRMPs) viz., Conventional-tillage without residues (CT-R), conventional-tillage with residue-retention in both crops at 3 t ha(-1) each (CT + R), zero-tillage without residues (ZT-R), and zero-tillage with residue-retention in both crops at 3 t ha(-1) each (ZT + R); and five organic-nutrient-management-practices (ONMPs) in both crops viz., 100 % RDF (N-1), 100 % RDN through FYM (N-2), 100 % RDN through VC (N-3), 100 % RDN through FYM + Biofertilizers + Cow-urine + Panchgavya + Jeevamrut (N-4), and 100 % RDN through VC + Biofertilizers + Cow-urine + Panchgavya + Jeevamrut (N-5), in split-plot-design replicated-thrice. Among TRMPs, ZT + R enhanced system-productivity (SEY) by similar to 17.2 % over CT-R, besides improved soil available-N, P, K by 6.4, 6.5 and 6.5 %, respectively. SMBC, SMBN and SMBP were higher under ZT + R by 16.2, 21.5 and 10.8 % over CT-R, respectively. ZT + R had higher soil enzyme activities of DHA, Acid-P, ALP, URA, and FDA over CT-R by 19.4, 20.7, 21.5, 20.7 and 15.2 %, respectively. ZT + R also had higher VLC, ACP, LI and CMI over CT-R. Among ONMPs, the natural-farming based ONMP, N-5 considerably improved SMBC, SMBN, SMBP, FDA, DHA, Acid-P, URA, and ALP by 12.7-12.9 % over N-1 (100 % RDF). ONMP-N-5 improved the available-N, P, K content over N-1 by 6.6, 5.8 and 6.7 %, respectively. ONMP-N-5 had higher (p < 0.05) microbial-count, VLC, APC, LI and CMI; however, system-productivity was similar to 4.1 % lower than N-1 in this two-years' short-study which further need investigation in multi-location long-term experiments. Overall, the dual-crop basis ZT + R at 6 t ha(-1) year(-1) + NF-based ONMPs (N-5) may harness higher and sustained productivity under SWCS besides advancing soil-health and soil carbon-pools in sandy-loam soils of north-Indian plains and similar soils across south-Asia.