Topics in Subtropics

Water moves in a wetting front. When irrigation water hits the soil it moves down with the pull of gravity and to the side according to the pull of soil particles (more lateral with more clay).

Growers are still calling in about avocados with thinning canopies, fruit drop and sunburn and leaf death. Coastal avocados are always difficult to irrigate. Mild weather followed by dry windy conditions means growers have to scramble to get water on.

Citrus response to irrigation water deficits have demonstrated that sensitivity of yield to water stress is dependent on the phenological phase in which water stress was applied. Adequate water supply is of major importance during citrus flowering and fruit set.

Recently I was asked why an irrigation schedule could be projected for almond and citrus in the Central Valley (Almonds:http://cekern.ucanr.edu/Irrigation_Management/Almond_Drip_-_Microsprinkler_- _Flood_Weekly_ET/Citrus: http://cekern.ucanr.

There is some variability in citrus susceptibility to both the psyllid (Westbrook et al and Hall et al) and the bacterial infection (Shokrollah et al and Stover and Mc Collum).