Managing Irrigation in the Presence of Groundwater

A method was developed to use lysimeter data for groundwater contribution to crop water use in the irrigation scheduling procedure for a subsurface drip irrigated field underlain by shallow groundwater. The method was tested on a 24 ha drip system installed in a high water table area located on the west side of the San Joaquin Valley. Data on applied water, evapotranspiration and plant dry matter indicated that the crop used nearly 130 mm from the saline shallow groundwater. The amount of water extracted from the groundwater could be increased if a fully-automated feedback system could be developed.