To obtain maximum yields of barley in the San Joaquin Valley, a normal (12? to 14?) pre-irrigation and at least one supplemental crop irrigation are required, according to these studies. When a heavy pre-irrigation is applied, the soil may be wetted below the potential rooting depth of the barley, in which case the moisture would not be available to the plants.

Don A. Patterson and Jim Fisher of Boston Ranch, Westhaven, assisted in conducting this experiment.