Effect of Transplanting Dates, Cultivars and Irrigation Regimes on Microclimate and Yield of Rice

A field experiment was conducted at BCKV, Kalyani, West Bengal (Latitude 22°59’13’’ N, Longitude 88°27’20’’ E) to evaluate the performance of different rice cultivars grown during kharif season of 2017. The experiment was laid down in a split split-plot design where four dates of transplanting (16^th June, 30^th June, 14^th July and 28^th July) were allotted in main plot, three rice cultivars (Nayanmani, Satabdi, Swarna) in sub-plot and two irrigation regimes (Optimum and Deficit) in sub-sub plot. Result revealed that the grain yield (4365 kg ha⁻¹) was recorded in 16^th June transplanting, highest which significantly declined by 15%, 31% and 36% respectively with delay in transplanting. Deficit irrigation resulted 851 kg ha⁻¹ less grain yield compare to optimum irrigation condition (3915 kg ha⁻¹). Grain yield under different variety was in the order of Nayanmani (4495 kg ha⁻¹) > Swarna (3008 kg ha⁻¹)>Satabdi (2965 kg ha⁻¹). The highest magnitude (0.98 g MJ⁻¹) of radiation use efficiency was noted under D₁, which decrease gradually with delay in transplanting time (0.79 g MJ⁻¹>0.64 g MJ⁻¹>0.58 g MJ⁻¹). The highest magnitude (0.87 g MJ⁻¹) of RUE was noted under optimum irrigation, _{which was 0.15 g MJ⁻¹ less under deficit irrigation. Among the varieties, the highest magnitude (1.10 g MJ⁻¹) of RUE was recorded under Nayanmani, which was 0.40 g MJ⁻¹ less under Satabdi. The lowest RUE (0.48 g MJ⁻¹) was noted under Swarna.}