Nutrient budget in Indian agriculture during 1970–2018: assessing inputs and outputs of nitrogen, phosphorus, and potassium

Abstract

Chemical fertilizer has contributed significantly in increasing food grain production in India. However, there are emerging concerns of environmental pollution at local scale, climate change at global scale, and sustainability of chemical fertilizer-dependent agriculture. Budgeting of nutrient is a valuable tool in assessing the nutrient use efficiency, nutrient mining, and environmental pollution. We constructed a field level top-down nutrient budget for food grain production in India since the onset of the Green Revolution in the country, i.e., 1970 to 2018, using equation-based empirical methods. Total nutrient input to Indian agriculture was 666.4 million tons (Mt) of N, 189.1 Mt of P, and 244.8 Mt of K during 1970–2018. Chemical fertilizer contributed 68.1% of N, 91.3% of P, and 28.8% of K towards the inputs. Nutrient budget for the last 48 years showed that there was positive balance of N (12.2 Mt), accumulation of P (11.7 Mt) but negative balance for K (157.9 Mt). Further, with the business-as-usual scenario, there would be positive balance of 276.2 Mt N, accumulation of 20.9 Mt P, and negative balance of 202 Mt K from Indian agriculture soils by 2050. The nutrient budget provides valuable information on the present status and balance of nutrient use and the trends with time, which will be helpful for reorienting the fertilizer use policies for sustainable agriculture.