Each lysimeter or PVC column is placed on a water pillow which has a tygon tube extended from the pillow. This tube is fixed vertically along and parallel to the PVC lysimeter packed with soil. A first estimate of the crop coefficient can be determined by estimating the percent cover . Irrigate when RAW is used up. See Alfalfa water use under moisture stress .
Roots extract most water from the upper half of the root zone .
Calculations of MAD are for the entire root zone. Water budget slide show. Scheduling irrigation's using reference evapotranspiration and an irrigation controller 6. Spreed sheet for irrigation sheduling using the water budget approach for chile. Stress Functions causing Et and yield to decrease to due to salinity streess, water stress, and nitrogen stress.