Drought management resources for growers

With a drought emergency declared in 41 California counties, the University of California has created and vetted drought resources to support growers during this challenging year.

“The deep integrated soil moisture profile between 0-39 inches is considered a strong drought indicator and is below the second percentile in much of the Sacramento Valley,” said Mallika Nocco, CE specialist, soil-plant-water relations and irrigation management, UC Davis. “Many growers and water managers are already making difficult decisions such as fallowing annual crops to allocate water for perennials, purchasing water transfers, or delaying new planting.”

Resources include Drought Tip Fact Sheets, which are peer-reviewed resources developed by the University of California Agriculture and Natural Resources with support from the California Department of Water Resources. Most of these fact sheets were created during the 2014-2017 drought years and are organized by crop type with specific fact sheets for almond, prune, walnut, and olive production.

Information about regulated deficit irrigation strategy is also provided. Prior to engaging in regulated deficit irrigation, it is strongly recommended to ensure that your irrigation systems have high distribution uniformity and optimal application efficiency. Low distribution uniformity will result in poorly regulated deficit irrigation across an orchard. More information is available at UC ANR’s maintenance of microirrigation systems site.

In most cases, careful monitoring of both ET and stem water potential are critical for regulated deficit irrigation and drought management. Crop specific weekly ET totals can be found on the Sac Valley Orchards ET page. The UC Davis Fruit and Nut Research and Information site has resources to learn how to measure stem water potential, calculate baseline stem water potential, and interpret stem water potential data by crop and growth stage. Sac Valley Orchards also has a series of how-to guides on measuring and interpreting stem water potential for everyone from beginners to long-time users. This can also be an opportune moment to start formally scheduling your irrigation and maintaining records using a tool like CropManage, which is science-based, free, and continually validated by UC scientists.

The Drought and Water Experts list contains UC experts on a variety of drought and water management issues across the state who can provide additional information and support.