NUT CROPS GROW PRIMARILY in the temperate zone and are irrigated to satisfy their moisture requirement. Irrigation of these crops is practiced where annual precipitation is less than 20 inches, or when rain does not fall during the water demand periods of the trees. Since nut trees are deciduous and are without leaves during the winter months, they use little water during that time. Precipitation occurring in the winter is stored in the soil if the profile is deep and uniform. In the Bakersfield area of California where this study took place, precipitation in the winter is limited to about 6 inches per year.