Nitrogen budgeting of rice-wheat cropping system under long-term nutrient management in an Inceptisol of north India

Abstract

In crop production, calculating nitrogen (N) inputs and outputs are essential for tracing losses to enhance fertilizer N use efficiency, crop productivity, and environmental sustainability. The present study reports the N balance sheet of a 19-year old nutrient management experiment on a rice-wheat system in an Inceptisol of the subtropical region of North India. Long-term application of fertilizer (N, NP, NPK) and manures (FYM: farmyard manure, GM: green manure, CR: crop residue) enhanced total soil N by 19 to 66% and total organic carbon by 14 to 66% over the control. The grain yields of crops in NPK + FYM were higher by 17% than NPK and 72% than the control (with no fertilizer). The per cent N loss of applied N was minimum under NPK + FYM (44%) and maximum under N (67%), whereas NPK + CR (50%) and NPK (48%) were comparable. Long-term nutrient management significantly affected N uptake and N use efficiency indices. The reduced N losses in balanced and integrated nutrient management improved rice-wheat productivity and mitigated environmental pollution.