Coping with Drought
THREE UC MEETINGS were held throughout almond growing regions in California in recent months to help growers deal with the current and future droughts. At the most recent March 31 meeting, UCCE Irrigation Specialist David Goldhamer reviewed principles that apply to a severely restricted water supply for almonds. Among his observations:
- Growers should stretch water use over as much of the season as possible and in proportion to almond evapotranspiration (ET˚);
- Growers on a limited water budget should opt for fuller irrigations at critical stages rather than smaller doses of more frequent waterings;
- Growers should save enough water for post-harvest applications during bud differentiation from late August to early September to preserve next season's crop production.
- While the goal is to retain leaves on trees until fall, growers should not be afraid of partial pre-harvest defoliation.
UC Farm Advisors Brent Holtz and David Doll said that, in addition to checking soil moisture status and tracking ET˚, growers should also use a pressure bomb to schedule irrigations according to stem water potential and tree stress.
Micro-irrigation system efficiency is crucial and Larry Schwankl, UC irrigation specialist, gave an update on "Fine tuning your micro-irrigation system."
UC irrigation experts have urged caution with dramatic measures, such as stumping or dehorning. To that end, a new ABC-funded research project led by Ken Shackel, UC Davis, at Nickels Soil Lab in Arbuckle is looking at the long-term tree responses to various canopy reduction scenarios and actual almond water requirements for survival. Early estimates place that minimum amount at 6 to 12 inches per season.
The ABC has developed a drought management portal on its Web site to provide a one-stop resource for information.