Pistachios Prove as Salt Tolerant as Cotton

 
Managing salinity and brackish drainwater on the Westside soils of the San Joaquin Valley remains a challenge. Environmental/economic concerns and legislation have closed many tile drains and forced growers with drains still operating to deal with the effluent on their own land. In some cases this water can be recycled (possibly blended with fresh water) on salt-tolerant crops. Cotton and sudangrass hay traditionally filled this role, but are often unprofitable. Pistachios, a profitable crop on the Westside, are known to grow in saline soils in Iran. The salt tolerance threshold for California pistachios was previously unknown.

 

 
Nine years of UCCE research completed in 2002 revealed that pistachios can be irrigated with drainwater as saline as that tolerated by cotton. The replicated study was set up by Louise Ferguson, Blake Sanden and Steve Grattan in a 40 acre pistachio orchard planted on clay loam soil south of Kettleman City. Saline irrigation treatments used three levels of salinity and a sodium-calcium ratio typical of Westside drain water. California Aqueduct water was used as the control comparison. All treatments were applied to four different rootstocks. During the trial, no significant difference in yields was evident up to the middle level of salinity (8 dS/m). This confirmed findings from Iran and from a Riverside USDA Salinity Lab study of salt tolerance in one-year-old pistachios.
 

 
The high degree of salt tolerance shown by pistachios in this trial, similar to cotton, allows some Westside growers a possible permanent crop for diversification and may result in the reuse of 3,000 to 8,000 acre-feet of drain water yearly in Lost Hills Water District alone. These results as well as production experience elsewhere on the Westside have expanded pistachio plantings across 4,000 acres previously deemed suitable for only cotton/grain rotations. This benefits statewide water conservation and helps growers maintain sustainable farming operations by recycling drainage water.
 

Supporting Unit: Kern County Soils, Irrigation, and Agronomy
 
Blake Sanden
Irrigation Management & Agronomy Farm Advisor
UC Cooperative Extension
1031 S. Mt Vernon Ave., Bakersfield, CA 93307
(661) 868-6218 (661) 868-6208 (fax)
blsanden@ucdavis.edu