Irrigation Water Requirement Estimation for Wheat by FAO Penman-Monteith Method: A Case Study of Barind Area, Rajshahi, Bangladesh

The study was focused on analyzing the irrigation water requirement of Wheat in Barind area of Bangladesh. The study was carried out from 2002 to 2011 in nine upazillas of Barind area under Rajshahi district. Reference Evapotranspiration was estimated using FAO Penman-Monteith method. Reference Evapotranspiration and crop coefficient of selected crops were used for estimating crop water requirement. By using estimated effective rainfall and crop water requirement, the irrigation water requirement was determined. The maximum evapotranspiration was estimated in 2004 and minimum was estimated in 2011 during the period of 2002-2011. The irrigation water requirement for Wheat was higher in the vegetative and mid-season stage from December to January and comparatively less irrigation water was required in initial and maturity stage. IWR decreases in the month of March as wheat was in maturity stage. It was also found that irrigation water requirement was less in the maturity stage as compared to the initial stage.