Optimising nutrient use efficiency under zero tillage operations in Rice - Maize cropping system in Coochbehar and Malda district of West Bengal

The project objective was to determine the nutrient requirement of high yielding variety (HYV) rice-hybrid maize cropping system cultivated under zero tillage. The project was initiated in 2015 in two districts of West Bengal, namely Coochbehar and Malda, having differences in agro-ecological characteristics. Coochbehar district primarily has Terai soil, while Malda is in old alluvial soil. During kharif season, rice was grown in 15 farmer’s fields from each district. The treatments included application of different doses of fertilizer such as T1 (ample NPK), T2 (-N), T3 (-P), T4 (-K), and farmer’s fertilizer practice (FFP) under HYV rice-hybrid maize cropping system. The nutrient recommendation for ample NPK plot was decided based on Nutrient Expert® (NE) software for rice and maize.

The HYV rice yield in the Coochbehar district for 2015 kharif is reported here. The average rice yield in Coochbehar for plots receiving NE recommended fertilizer was 5.2 t/ha with a range from 3.5 to 6.2 t/ha. The plot receiving NE recommended fertilizer produced higher yield compared to FFP. The highest yield increase in NE plots compared to FFP observed was 1.9 t/ha, while the minimum yield gap observed was 0.1 t/ha. The average grain yield in omission plots highlights that N is the most limiting nutrient, with an average yield loss of 840 kg/ha; followed by K omission (yield loss of 570 kg/ha) and P omission (yield loss of 470 kg/ha). It is expected that both the crop response and depletion of soil nutrient status will be higher in the coming seasons.