DETERMINATION OF CROP COEFFICIENT (Kc) FOR TRANSPLANTED AMAN RICE

Abstract

The study was conducted in the Experimental Farm of Hajee Mohammad Danesh Science and Technology University, Dinajpur with a view to determine Crop Coefficient (Kc) value from irrigated T. Aman rice during the T. Aman season of 2004. The results showed that on an average, the seasonal evapotranspiration (ET) rate was 4.28 mmi/day. The total ET demand in T. Aman season was calculated to be 437 mm and the peak demand was 4.41 mm during the month of August. The effective rainfall during the growing period was 526 mm which is more than the total ET demand of 437 mm. The seasonal crop evapotranspiration (ETc) using the lysimetric method, reference evapotranspiration (ETO) by computer program ‘CROPWAT* and Kc values were determined. The determinated values of crop coefficients for T. Aman rice at the four stages (initial, crop development, reproductive and maturity) were 1.06, 1.03, 1.07 and 1.07. The mean Ke value for T. Aman rice for growing season was found to be 1.06 and also found the highest crop coefficient value (1.07) at reproductive and maturity stage and lowest value (1.03) at the development stage.