Estimation of Actual Evapotranspiration (ETa) of Major Crops of a Distributary of Mahanadi Canal Command Using CROPWAT 8.0 Model by Penman: Montieth Method

Abstract

This paper aims to estimate Actual Evapotranspiration of major crops by using CROPWAT 8.0 software in 2A canal command of Mahanadi of Dhamtari district. Actual evapotranspiration is a key process of hydrological cycle and a sole term that links land surface water balance and land surface energy balance. Irrigation is an essential part of different crops because rainfall is not enough for irrigated farmland. Long term daily meteorological data including rainfall, maximum temperature, minimum temperature, relative humidity, wind speed and sunshine hours of IMD station data was used as input data in modified Penman method and CROPWAT 8.0 model. The crop stage data, including the value of Kc in, Kc mid, Kc end for the selected crop was obtained from Department of Irrigation the rooting depth, critical depletion and crop height of different crops are taken from FAO Irrigation and Drainage Paper 56. The Penman Monteith method was used to estimate ETo and ETc respectively. The major crops in 2A canal command area are Paddy, Wheat, Chickpea , Summer Paddy. Based on the intensive study of this paper, daily basis meteorological weather data was recorded from 2007 to 2021 were used to obtain the result. The study detects that Penman–Montieth method is the best method to estimate Actual Evapotranspiration of all crops.