Deficit Irrigation Strategies for Sorghum in the San Joaquin Valley of California.

The responses of grain and forage sorghum cultivars to irrigation timing and irrigation amounts ranging from full irrigation to several levels of deficit irrigation were evaluated in three years of furrow irrigation trials in the San Joaquin Valley of California.   The first two years of trials were conducted in a deep loam soil, while the third year trials were conducted in both a sandy loam soil site and a clay loam soil site.  Types of sorghum tested in this series of trials and the timing of harvest operations were for use for silage animal feed.  In order to be able to estimate total crop water use as a function of irrigation treatment, applied water was monitored in all treatments, and total season soil water use was estimated with planting timing and post-harvest gravimetric soil water measurements.  Impacts of irrigation treatments on yield, plant water status and some components of silage quality will be discussed.