Resource Conserving Techniques for Improving Nitrogen-Use Efficiency

Abstract

The use of nitrogen fertilisers has played an instrumental role in enhancing agricultural productions the world over including India. Currently, about 83 million tons N is used in agriculture globally. A large portion of applied N is lost through leaching, volatilisation and runoff, and only 50% of applied N is assimilated by the crop plant. Recently, there have been serious concerns about environmental footprints of N fertilisers, particularly greenhouse gas emissions from the rice fields and escalating costs of fertilisers beyond farmers’ reach. To meet the growing need for N fertilisers due to the rise in food requirement for ever multiplying population on the one hand and an increasing environmental and atmospheric pollution on the other, improving nitrogen-use efficiency (NUE) appears to be a viable solution. Certain resource conserving techniques, such as laser land levelling, zero or minimum tillage (save fuel), direct seeding, permanent or semi-permanent residue cover, new varieties that use plant nutrients more efficiently, furrow irrigated raised bed (FIRB) technology, system of rice intensification (SRI), direct seeded rice (DSR), precision farming techniques, use of leaf colour chart (LCC), chlorophyll meter, GreenSeeker, etc. have been shown to increase crop yields and NUE. For example, the use of optical sensors like GreenSeeker, chlorophyll meter and FIRB saved 25–50%N. Even laser levelling has been reported to increase NUE by 6–7% in India. Hence the use of such resource conserving technologies should be facilitated and supported for the sustainability of agricultural production and the natural resource base (land and water).