Long Term Effects of Conjunctive Nutrient Management Practices on Soil Quality in Maize (Zea mays) –Mustard (Brassica compestris var. sarson) Rotation under Rainfed Hill Inceptisol Soils

Abstract

ABSTRACT The decline in the yields of most of the crops grown in the hill Inceptisol soils of Jammu region of India , is largely attributed to the gradual decrease in soil quality, owing to the poor soil-nutrient management practices. The indicators and the overall indices of the soil quality can be improved to a greater extent through the conjunctive use of organic and inorganic sources of nutrients, instead solely depending upon the inorganic sources. Therefore, a long-term study was conducted with the prime objective to assess the long-term effect of different conjunctive nutrient management practices on soil quality indicators and indices in hill Inceptisol soils of Jammu region of India. The results of the study revealed that after 11 years the order of superiority of the treatments in terms of maize grain yield was 100% NPK (60:40:20 kg ha−1) (T2) (2186 kg ha−1) > 50% NPK + 50% N (FYM) (1961 kg ha−1) (T7) > 50% NPK + 50% N (crop residue) (1789 kg ha−1) (T6) > 50% N (FYM) (1510 kg ha−1) (T5) > 50% NPK (1436 kg ha−1) (T3) > 50% N (crop residue) (1426 kg ha−1) (T4) > control (1183 kg ha−1) (T1). In case of mustard crop, the order of superiority was T7 (1157 kg ha−1) > T5 (960 kg ha−1) > T6 (903 kg ha−1) > T2 (874 kg ha−1) > T3 (783 kg ha−1 > T4 (710 kg ha−1) > T1 (541 kg ha−1). The percent contribution of key indicators toward soil quality index was in the order of available sulfur (S) (31.9%) > microbial biomass carbon (MBC) (31.8) > dehydrogenase assay (DHA) (8.36%) > pH (8.05%) > electrical conductivity (EC) (6.01%) > organic carbon (OC) (4.87%) > available zinc (Zn) (4.56%) > available phosphorus (P) (4.45%). The relative order of performance of treatments in terms of soil quality indices was T5 (1.52) ≥ T7 (1.52) > T6 (1.46) > T2 (1.38) > T3 (1.33) > T4 (1.25) > T1 (control) (0.97). Our study has clearly indicated that after 11 years, the conjunctive use of organic sources of N such as FYM and crop residues in combination with inorganic sources (@ 50:50 on the basis of N equivalents) proved very effective in improving the soil quality indicators and indices under maize (Zea mays) - mustard (Brassica campestris var. Sarson) crop rotation in rainfed hill Inceptisol soils.