Effects of fertilization on soil aggregation, carbon distribution and carbon management index of maize-wheat rotation in the north-western Indian Himalayas

Abstract

Abstract The impacts of the resource conservation practices can be evaluated in short-term through carbon management index (CMI) that conceptualizes the carbon lability and soil aggregation. To test this hypothesis, we investigated the labile organic carbon (LOC) pool and CMI in relation to runoff, soil loss and maize-wheat system productivity on 2% sloping crop lands of Indian Himalayan region in a study (2009–2014) where different nutrient management practices were adopted. Results showed that all integrated nutrient management (INM) practices (mineral fertilizers with different organic sources like farmyard manure (FYM), vermi-compost (VC), green manure (GM) and poultry manure (PM) enhanced soil aggregation compared with only mineral fertilization (NPK). Among all the treatments, the highest water-stable macroaggregates (+25%) in the 0–5 cm soil layer were recorded in 50% NPK + 50% FYM (7.5 t ha−1) treatment. Aggregate size of >2000, 250–2000, 53–250 and 2000 to