Determination of Crop Coefficient for Capsicum (Capsicum annumm L.) in Eastern Himalayan Region through Field Lysimeter

A Crop coefficient (kc) was determined for Capsicum annumm L. (hot pepper) with the help of UMS-GmBH cylindrical field lysimeter of 30 cm diameter and 120 cm deep and Penman-Monteith FAO-56 model. Penman-Monteith model is the universally adopted standard model for estimation of reference evapo-transpiration (ET0) based on local weather parameters. Eight other models viz. Modified Penman Method, Hargreaves equation, Samini Hargreaves equation, Thorthwaite equation, Solar Radiation Method, Net Radiation Method, Blaney-Criddle Method and Radiation Method were also used for estimation of ET0 and compared with Penman-Monteith model to find out the accuracy of prediction with limited weather parameters. Scatter plot and paired t-test were used for comparison. Out of all these models, Blaney-Criddle Method was found to yield similar results as given by Penman-Monteith model. The values of crop evapo-transpiration (ETc) were varying from 1.11 mm d−1 to 3.12 mm d−1. kc is the ratio of ETc to ET0. The highest kc value was obtained during the maximum vegetative growth in 8th week after transplantation. The crop-coefficients for three growth stages viz. initial, mid and maturity were found to be 0.33, 0.64 and 0.30, respectively.