FORAGE PRODUCTION AND SOIL RECLAMATION USING SALINE DRAINAGE WATER Stephen Kaffka, Jim Oster, Dennis Corwin 1 INTRODUCTION In semi-arid or arid locations, salinity can become a problem for farmers who irrigate crops (Hillel, 2000). This is the case in the western San Joaquin Valley of California where soils are naturally saline and where the presence of shallow, saline water tables threatens crop production. Without a means to dispose of drainage water in the western San Joaquin Valley, increasing amounts of farm land will become salt impaired. The use of underlying groundwater and limited numbers of evaporation basins for disposal of the large volume of drainage water produced is not sustainable. A multi-disciplinary team has assembled to test the hypothesis that saline-sodic drainage water can be used in an environmentally sound manner for forage and livestock production. The goal is to use salt tolerant forages to support economic weight gain by cattle or sheep, or for sale to dairies and other cattle feeding operations. If economic forage and livestock production can be based on the reuse of drainage water or other waste waters in the San Joaquin Valley, this unused water will be transformed from an environmental burden into an economic asset. The amount of water that must be disposed to groundwater or in evaporation ponds will be reduced dramatically. Other economic and environmental benefits associated with irrigated pasture also will be realized. The study’s objectives are to: 1. Measure forage biomass accumulation, nutrient and trace element uptake, and the quality of salt tolerant forages produced using saline-sodic drainage water. 2. Monitor the mineral status and general health of cattle and measure the growth rate of cattle fed or grazing forages produced with drainage water.3. Quantify the effects of saline-sodic drainage water on overall water use, drainage water quantity and quality, salt and trace metal balances, soil organic matter, and soil chemical and physical properties over time.4. Model changes in important soil chemical, physical and biological properties at the local and field scale. 5. Develop economic models for drainage water reuse on forages. This paper reports forage quality and yield data to date. METHODS An 80 acre site near Stratford in Kings County was developed to study the use of drainage and other waste waters for the production of forages and cattle. The site had been abandoned for annual crop production and was saline and highly variable. The site was leveled and tile drains were installed at a depth of 4 feet, 120 feet apart. A detailed baseline soil assessment for soil 1 Stephen Kaffka*, Agronomy and Range Science, UC Davis, (srkaffka@ucdavis.edu , tel: 530-756-8004); Jim Oster, Environmental Sciences, UC Riverside; Dennis Corwin, USSL, Riverside. In: Proceedings, National Alfalfa Symposium, 13-15 December 2004, San Diego, CA, UC Cooperative Extension, University of California, Davis, 95616. (see http://alfalfa.ucdavis.edu for this and other proceedings)