Evaluation of leaf-colour chart for need-based nitrogen management in maize (Zea mays) grown under irrigated condition of Mollisols

A field study was conducted at Pantnagar, Uttarakhand, during the rainy (kharif) season of 2013 and 2014 using leaf-colour chart (LCC) as a tool to know nitrogen demand in maize (Zea mays L.) crop and to evaluate and establish LCC threshold value for saving fertilizer N and achieve higher grain. The LCC-treated plots showed higher increase in grain yield/kg N applied over fixed time interval of N treatments. Using of LCC score 3.0 with 90 kg N/ha showed grain-yield equivalent to 120 and 150 kg N/ha applied at fixed time interval and gave higher recovery efficiency to the tune of 12.1–18.1 unit and 4.1–5.1 kg higher grain yield/kg fertilizer N applied, whereas LCC 5.0 resulted in significant higher grain yield. Application of fertilizer N with 1.0 unit increase in LCC score significantly enhanced grain yield but no response of fertilizer N was seen when applied at reproductive stage. Soilavailable N increased significantly with increasing the LCC values and was significantly superior at LCC < 5.0 followed by 150 kg N/ha applied at fixed time interval. Leaf-colour chart-based N management reduced anthesis silking interval by 0.2–1.4 days compared to fixed time interval. Strong correlation was obtained for LCC score with N content and grain yield at the reproductive stage. Leaf-colour chart values against grain yield indicated that LCC 4.6 at vegetative stage and LCC 4.9 at reproductive stage can guide crop demand-driven N application to enhance yield and saving N in maize under irrigated condition of Mollisols in tarai region.