Estimation of evapotranspiration under polyhouse and open field conditions in capsicum

Field experiment was conducted at Agricultural Engineering College and Research Institute, Kumulur, Tamil Nadu, to estimate crop evapotranspiration and crop coefficient of capsicum under polyhouse and open field conditions for the two consecutive seasons during 2019. Microclimatic parameters like maximum and minimum temperature (ºC), relative humidity (%) and light intensity (lux) were recorded during the study. EM 50 soil moisture sensors were used to observe the soil moisture status for the entire crop growth period. The actual crop evapotranspiration was worked out by using standard soil water balance equation. The crop coefficient for capsicum was estimated for different crop growth stages. During winter season, crop coefficient for initial, developmental, middle and end stages were 0.49, 0.76, 0.98 and 0.88, respectively, for the crop grown inside polyhouse and same were 0.59, 0.77, 1.02, 0.90, respectively, for the crop grown outside condition. The water use efficiency of capsicum under drip irrigation was calculated as 56 Kg/ha.mm during summer season and 66.7 kg/ha.mm during winter season similarly, the water use efficiency of 11.7 kg/ha.mm and 17.6 kg/ha.mm during summer and winter season, respectively in open field condition.