Effect of legumes on nitrogen economy and budgeting in South Asia

Increase agricultural productivity and mitigate the demand of food security of the rapidly flourishing population the primary nutrient element nitrogen (N) has been playing a paramount role in the crop production system. The denitrification losses N in the form of nitrous oxide (N 2 O) are very much harmful to the environment because it causes global warming, detrimental effects on a human being, animal and the ecosystem. The losses of N into the environment affect ecosystem services, environmental sustainability, soil health, decline factor productivity and affects aquatic life. Intensive and improper application of inorganic nitrogenous fertilizer in the cropping system incurred higher investment of capital, more energy budgeting and carbon (C) footprint, which causes environmentally and economically unacceptable crop production system. To, tackle such consequences the inclusion or incorporation of grain legumes in the cropping system reduces atmospheric pollution, increases the N budgeting in the soil ecosystem, improve environmental sustainability, soil health, soil sustainability and agricultural productivity. Further, the nitrogen use efficiency (NUE) can be increased by adopting some tools like leaf colour chart (LCC), green seeker, site-specific nutrient management, SPAD (soil plant analysis development) meter along with the application of slow-release nitrogen fertilizer such as neem coated urea, sulphur coated urea, polymer-coated urea etc. This chapter is focused on the N budgeting of South Asia, the consequences of N on the environment, soil, water and its management strategies. Therefore, public consciousness, an adaptation of modern technology and practising legume-based crop rotation is necessary for improving environmental quality and a cleaner production system.