ESTIMATION OF CROP EVAPOTRANSPIRATION WITH DUAL CROP COEFFICIENT APPROACH

Abstract

The present study is concerned with the estimation of reference crop evepotranspiration with the dual crop coefficient approach for wheat Crop. In the dual crop coefficient approach, the effects of crop transpiration and soil evaporation are determined separately. Two coefficients are used: the basal crop coefficient (Kb) to describe plant transpiration, and the soil water evaporation coefficient (Ke) to describe evaporation from the soil surface. Crop evapotranspiration for different stages of the crop period in case of wheat crop is obtained by conducting water balance study with Lysimeter Setup models. Suitability of reference evapotranspiration estimation model in computing crop evapotanspiration for the local agro—climate has been investigated .Three reference evapotranspiration estimation methods, Penman Montheith, FAO-24 corrected Penman and FAO Pan Evaporation are used to compute reference evapotranspiration from the available meteorological data. The FAO recommended crop coefficient modified for the local climate using dual crop coefficient analysis .Actual crop Evapotranspiration for different growth stages of crop grown i.e,wheat is obtained by conducting water balance studies on Lysimeter set up .The field observed (water balance) and computed value of crop evapotranspiration ,using single and dual crop coefficient approach are compared.