Tuesday, November 6, 2007 - 3:45 PM
230-16

Potential Role of the Halophyte Salicornia bigelovii in Reducing Volumes of Hypersaline Drainage Waters.

Stephen Grattan, University of California, Davis, One Shields Ave., Coop. Ext. Dept. of LAWR, Davis, CA 95616, Sharon Benes, California State University-Fresno, Dept. of Plant Science/ CA State Univ. Fresno, 2415 E. San Ramon Ave. Ms/as72, Fresno, CA 93740-8033, and Doug Peters, Hansen Agricultural Center, University of California, Davis, 14292 W. Telegraph Road, ANR Central Coast & South Region, Ventura, CA 93060.

Salt tolerant and halophytic crops are important components in drainage water reuse systems as a means of reducing drainage volumes and for removing nutrients and potentially toxic trace elements from the effluent that produce adverse affects on receiving water bodies. Salicornia bigelovii is a promising halophyte as the final crop in a saline drainage water reuse sequence. We conducted a greenhouse study to compare the growth, quality and consumptive use of S. bigelovii when irrigated with hypersaline water prepared from diluting either seawater or solar-evaporator water (i.e. drainage water). Results have shown that S. bigelovii grows well over the range of salinity treatments (10-45 dS/m) regardless of whether it is irrigated with hypersaline drainage water or seawater. At the higher salinity levels, plants generally performed better in the seawater treatment than in the drainage water treatment. Moreover, this leafless plant, comprised of succulent stems, can maintain evapotranspiration (ET) rates comparable to reference ETo. Using stable isotopes changes in the drainage water, we found that high ET rates were due mainly to high transpiration. Therefore this plant has excellent potential for reducing drainage volumes and minimizing the environmental impact from this tainted water. Salicornia has a remarkable ability to accumulate salts in its shoot tissue (ash content was usually between 45-55%). Se concentrations is shoot tissue in plants irrigated with drainage water were relatively low the second year (< 100 µg/kg dw) and compared to the first year (500-2100 µg/kg d.w.) due to different sources and concentrations of Se in the solar pond water used to prepare treatments. The 1998 study supports the recent hypothesis that salinity high in sulfate mitigates boron's detrimental effect.