International Journal of Academic and Applied Research (IJAAR)   Year: 2018 | Volume: 2 | Issue: 9 | Page No.: 8-13 Vegetation Index Based Coefficients to Estimate Crop Evapotranspiration of Wheat in Punjab, Pakistan Sahrish Anwar Abstract: Vegetation index based crop coefficients are widely used to determine crop evapotranspiration (ETc) for estimating water need at its different stages of growth for sustainable agricultural development. The recent study was carried out in Punjab where, Wheat is the main food crop. Our main objective is to estimate ETc of Wheat by using satellite based vegetation coefficients. Reference evapotranspiration (ET0) was calculated by Penman-Monteith method. Climate data of 24 years (1991-2015) were used to calculate ETo. About 112 Landsat 8 satellite images for Rabi season (year-2016) were utilized in the study. Normalized difference vegetation index (NDVI) was derived by using satellite data in ArcGIS 10.2 software. Further NDVI was used to determine vegetation coefficients (Fov) for Wheat. ETc was calculated by multiplying ETo with Fov. Seasonal ETo for Wheat was 568 mm or 3.43 acre ft/year and Seasonal ETa was 558 mm or 328 acre ft/year. Seasonal ETc map showed spatial distribution of wheat in Punjab highlighting areas with low to high water requirement. The study provides information about use of water for irrigation and can be helpful for farmers, field managers and policy makers. Further studies should be investigated for other food and cash crops of Pakistan.