Seasonal evapotranspiration estimation using canopy reflectance: a case study involving pink beans.

In the estimation of crop evapotranspiration (ET) crop coefficients are employed to simulate soil moisture in the crop root zone. Remote sensing offers an excellent means of determining near real time crop coefficients for most irrigated crops. In the absence of prior knowledge of planting, emergence and/or full effective cover dates, canopy reflectance can be used to establish the growth rate of the crop, and subsequently can be used to fractionalize the reference ET for irrigation scheduling. This paper presents the results of extending the reflectance-based crop coefficient methodology, initially developed for corn, to pink beans. Simulation results indicate that the reflectance-based coefficients follow the actual crop growth in the field, and thus can simulate the measured soil moisture content.