Evaluating Precision Nitrogen Management Practices in Terms of Yield, Nitrogen Use Efficiency and Nitrogen Loss Reduction in Maize Crop Under Indian Conditions

Nitrogen (N) losses from the N sources such as manures, fertilizers etc. applied to crops are considered as the largest non-point source of nitrogen-nitrate pollution in surface and groundwater bodies. The extent of water bodies polluted with N is worsening day by day, worldwide, with its severe impact on the quality of drinking water. This necessitates the development of crop specific N management practices to reduce N losses from crop systems. Improvements in agronomic and recovery efficiency of nitrogen in crops are regarded as promising techniques to reduce N losses. With the hypothesis that precise N supply in maize employing LCC or CCM under a critical threshold value will augment the yield performances and Nitrogen Use Efficiency (AE(N) and REN) of maize, while reducing N losses, a two year study was conducted at Anand, India. Fifty percent reduction in basal N application and subsequent N applications based on LCC critical value 5 resulted in 12.30 and 12.25% increment in maize grain yield over recommended practices during the year 2015 and 2016, respectively. Significant improvement for total biological yield, grain protein accumulation in maize and total N uptake by crop was observed in the direction of N application using LCC threshold point 5, CCM threshold point 40 and recommended practice. Applying nitrogen at whatever the times LCC critical point drops <= 5 also recorded 4.09 and 4.17 kg gain in grain produced (over recommended practice) kg(-1) of N supplied (AE(N)), 0.16 and 0.17 kg gain in N uptake (over recommended practice) kg(-1) of N supplied (REN) during 2015 and 2016, respectively and a total reduction of 51.14 kg N loss ha(-1) (over recommended practice) for the entire study period. The study reveal that compared to blanket application, N fertilizers can be more efficiently managed with LCC threshold value 5 or CCM threshold value 40 for guiding N application with higher yield, NUE and reduced N losses in maize crop.