Title: POTENTIAL FOR CYCLIC REUSE OF SALINE DRAINAGE WATER FOR IRRIGATION OF TOMATOES.
Abstract: Reuse of saline drainage water for crop irrigation has been proposed as one strategy to reduce the drainage volume requiring disposal in California. A 6 y study to assess the feasibility of cyclic saline drainage reuse in a processing tomato/ cotton /cotton rotation was conducted. Treatments were: 1. fresh water applied throughout, 2. saline water applied after 1st flower to tomatoes, 3. saline water applied to tomato and the next cotton crop. Saline water generally improved tomato fruit quality, but did not reduce yields during the first 4 years. In year 6, yields were reduced 17% (n.s.) and 30% (p<0.05) in treatments 2 and 3 respectively, relative to the control. Monitoring of the root zone showed that boron has accumulated over time in saline treatments and may be limiting crop production more than soil salinity. Selenium was readily leached by periodic fresh water use and did not accumulate to levels of concern in tomato tissues. Other work has shown that salinity can enhance tomato susceptibility to root rot which may limit this practice in some areas. However, the data show that high value crops like tomato can be incorporated into saline reuse schemes if managed appropriately.