STUDY ON WATER BALANCE OF IRRIGATED T. AMAN RICE

Abstract

The study was conducted at the experimental farm of Hajee Mohammad Danesh Science and Technology University, Dinajpur, with a view to study on water balance of irrigated T. Aman rice. The water balance study was conducted in the T. Aman season of 2004.The experiment comprised two treatments viz. continuous standing water (1-7cm) and irrigation (5-7cm) after 3 days of disappearing of standing water. The field experiments showed that in T. Aman season 7% of the total supplied water (including rainfall) was required for land preparation, 30% was used for evapoptranspiration (ET), 45% was lost as seepage and percolation and the rest 18% was lost as surface runoff due to heavy rainfall and other unaccounted losses. Therefore, from this study it can be concluded that on an average only 30% of the supplied water in irrigated rice field is used as evapotranspiration and the rest 70% is lost by different processes. The irrigation treatment, irrigation after 3 days of disappearing of standing water is not applicable in T. Aman season due to rainfall. Therefore, water saving techniques like shallow application of water, if adopted properly may lead to efficient utilization of water through minimizing excessive losses of seepage and percolation.