Estimation of Crop Coefficients by Remote Sensing based Vegetation Index

Crop coefficient plays a vital role in estimation of crop evapotranspiration for irrigation scheduling in a canal command. Remote sensing-based vegetation indices can help in efficient irrigation water management, as the irrigation systems need near real-time spatial information on types of crop, area under irrigation, crop water requirement, etc. The Surface Energy Balance Algorithm for Land (SEBAL) was used for estimating actual evapotranspiration (AET) based on remotely sensed data. The summer groundnut crop coefficients were estimated using AET and ET₀. The FAO-56 method helped to estimate reference evapotranspiration (ET₀) and crop evapotranspiration using crop coefficient. The remote sensing based Normalized Difference Vegetation Index (NDVI) for different days of year (DOY) were derived using Landsat imageries for summer crop season in 2014. The relationship between the NDVI and K_c for different DOY was established to estimate the crop coefficients of summer groundnut at field and regional scales for different growth stages for the Ozat-II canal command of Junagadh district of Gujarat State, India. The developed equation might be useful for estimation of crop water requirement and irrigation scheduling of canal command using remote sensing data.