Nitrate as a bio-indicator for enhancing the nitrogen use efficiency in maize

Abstract

Maize has robust growth habit with high requirement of nutrients, particularly nitrogen. Rapid tests to assess thenutritional status on site can make easier decision of any adjustments in the nitrogen fertilization. Hence , a field experimentwas conducted during kharif 2017 at Main Agricultural Research Station (MARS), University of Agricultural Sciences,Dharwad to assess the nitrogen requirement using nitrate as a bio-indicator in maize to enhance NUE. Plant sap nitratecontent was measured on site using Cardy nitrate ion meter at critical stages under different levels of nitrogen. Differencein nitrate values between under supplied nitrogen to hundred per cent supplied nitrogen recommended were used as indicesfor application of deficit nitrogen. Results revealed that nitrate is a good bio-indicator of nitrogen status of maize at criticalstages. Supplementing the N based on sap nitrate test has saved 28.5 per cent nitrogen and enhanced nitrogen use efficiency.