Green Seeker and chlorophyll meter-assisted nitrogen management increased the rice productivity in direct seeded dry rice

Abstract

Prediction of nutrient requirements is crucial for successful decision-making in crop production. The objective of this experiment was to study the real-time nitrogen management (RTNM) in dry direct-seeded with Green Seeker and SPAD meter in rainfed rice. The experiment was done in a randomized block design with seven treatments viz. T1 : N omission, T2 : N applied as basal and active tillering (AT), T3 : N as basal, AT and panicle initiation (PI), T4 : N as basal and top dressing at NDVI threshold of 0.75, T5 : N as basal and at NDVI threshold of 0.8, T6 : N as basal and SPAD35, and T7 : N as basal and SPAD37.5. An early maturing drought tolerant rice variety Sahbhagi Dhan was drill seeded (dry) for this study. The soil of the site of the experiment was sandy loam, acidic with medium organic carbon, available nitrogen, phosphorus, and potassium. Basal application of 30 kg N ha-1 followed by top dressing of 20 kg N ha-1 two times at 35 and 63 DAS directed by NDVI threshold level of 0.8 (T5 ) was superior compared totherest of the treatment effects in terms of growth, productivity, profitability, nutrient, and energy use efficiency.