IMPACT OF IRRIGATION WATER PRICING ON WATER USE BY THE FARMENT’S OF GREATER DINAJPUR DISTRICT

Abstract

Study to ‘impact of irrigation water pricing on water use by the farmers’ covers 23 Upazilas of Panchagarh, Thakurgaon and Dinajpur districts having gross area of 6,66,048 ha and cultivable area of 5,39,499 ha (IWM, 2015). This study aimed to find out the variation of seepage and percolation loss at different crop growth stages, Crop Water Requirement, identifying different irrigation pricing methods and finally to develop the relationship between seepage & percolation loss and irrigation water pricing. In order to find out the impact of irrigation water pricing on water use by the farmers half blind and half perforated PVC pipes were installed at Ishania, Dinajpur, Maghkhuria, Thakurgaon and Guagram Pradhan Para, Panchagarh districts. At each district at least 5 pipes were installed keeping distance from one pipe to another pipe at least 50 meter. After installing PVC pipes depth of water level measured at a fixed time in everyday considering same reference level for measuring the seepage and percolation loss. Average seepage and percolation loss have been found 5.37 mm/day in Dinajpur district, 5.63 mm/day in Thakurgaon district and 6.43 mm/day in Panchagarh district. The evaporation loss data was collected from evaporation station and for entire season the average evaporation has been found 5.733 mm/day. After measuring seepage and percolation loss and evaporation loss the crop water requirement was calculated. The average crop water requirement has been found 11.10 mm/day for Dinajpur district, 11.30 mm/day for Thakurgaon district and 12.10 mm for Panchagarh district. The observed CWR has been compared with the simulated CWR using CropWat model. The soil textures for each field have been tested at the laboratory of Soil Resource Development Institute. It has been observed that seepage and percolation loss was different at different districts due to different type of soil textures and seepage and percolation loss was different at different crop growth stages. The seepage and percolation loss found very high at vegetative crop growth stage, medium at reproductive stage and lowest at ripening stage. It has been found that Seepage and Percolation loss have major impact on irrigation water pricing. Water pricing in Dinajpur district is lowest, Thakurgaon district is medium and it is highest in Panchagarh district due to highest seepage and percolation loss than other two districts. It has been found from the study, irrigation water pricing has a proportional relationship with seepage and percolation loss and crop water requirement. The seepage and percolation loss mainly depend on the soil texture, surrounding environment and topography of the study area.