Precision Nitrogen Management Through Crop Sensors on Growth and Yield of Aerobic Rice (Oryza sativa L.)

Aerobic rice is grown in well drained, non-puddled and non-saturated soils just like wheat and maize. Experimental results showed that water requirement of aerobic rice was 30 – 50 % less than flooded system which yields almost same as obtained in case of transplanted rice. N fertilization is the major agronomic practice that affects the yield and quality of aerobic rice. The fertilizer N use efficiency by rice is very low as partial factor productivity has decreased exponentially. Nowadays crop sensors are becoming popular for nitrogen management. Hence   field experiment was conducted to standardize the precision nitrogen management using crop sensors during kharif 2017 and 2018 at Zonal Agricultural Research Station, UAS, Bengaluru in sandy loam soil (pH 6.0; OC 0.51 %) with medium available nitrogen (318.13 kg ha^-1), phosphorous (34.18 kg ha^-1) and potassium (284.28 kg ha^-1). The experiment was laid out in RCBD with nine treatments, replicated thrice and cultivar used was MAS 946-1. The results revealed that nitrogen management through SPAD sufficiency index 96-100 per cent recorded significantly higher plant height (70.0 cm), number of tillers (42.8 hill^-1), leaf area (2720 cm² hill^-1), total dry matter (133.8 g hill^-1), higher productive tillers hill^-1 (34.0), panicle length (23.2 cm), test weight (24.8 g) and resulted in higher grain (7189 kg ha^-1). The nitrogen management through SPAD sufficiency index 96-100 per cent recorded higher nutrient uptake (130.5, 24.0 and 120.0 kg NPK ha^-1, respectively), gross returns and net returns. Whereas, higher B: C ratio was found with GreenSeeker based nitrogen management.