Ground-based Remote Sensing of Corn Evapotranspiration under Limited Irrigation Practices

Ground-based remotely sensed data were used in two major approaches to estimate crop coefficient and evapotranspiration (ET) over two treatments of limited-irrigation corn in northeastern Colorado. The first approach, known as the reflectance-based crop coefficient, takes advantage of the unique relationship between crop coefficients (Kc) and vegetation indices of agricultural crops. The second approach is more complex and approximates the latent heat flux over a crop canopy as the residual of the surface energy balance equation. Implemented methods resulted in crop coefficients similar to what is expected for corn in the semi-arid climate of northeastern Colorado, with basal crop coefficients being lower than the single Kc. Crop coefficient estimates were then used to calculate corn water consumption over a 4-week period. Total corn transpiration ranged from 135 to 169 mm, while total corn ET varied between 163 to 200 mm, for all of the methods and treatments. 1 Civil and Environmental Engineering Department Colorado State University, 1372 Campus Delivery Fort Collins, CO 80523-1372 Tel: (970) 491-3381 e-mail: [email protected]