How can ET be used to schedule irrigation?
With the use of a soil water balance or budget, daily evapotranspiration (ET) amounts are withdrawn from storage (or the balance of plant available water) in the soil profile. Rainfall or irrigation amounts are added to soil water storage. Should the water balance calculations project soil water to drop below some minimum level, irrigation is indicated. Weather forecasts enable prediction of ET rates and projection of soil water balance to indicate whether irrigation is needed in the near future (CSU Extension).
