Submitted to: Plant and Soil
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/20/2002
Publication Date: 7/14/2003
Citation: Banuelos, G.S., Sharmasarkar, S., Cone, D., Stuhr, G. 2003. Vegetative approach for improving the quality of water produced from soils in the westside of central california.. Plant and Soil Journal.Vol (249): 229-236 Interpretive Summary: Expansion of agricultural production will become increasingly dependent upon expanding new supplies for irrigation. Water availability could be enhanced through the judicious and proper use of saline drainage water. Drainage water produced in the San Joaquin Valley, CA can contain unusually high levels of B, Se, and salinity. When using water of this quality for irrigation, the long-term accumulation of B and Se in the soil must be seriously considered for agronomic and ecotoxicological reasons. A field study was established to evaluate both plant growth and trace element accumulation in a forage legume and grass irrigated with a B/Se-laden effluent. After two years of irrigation with the drainage effluent, annual yields of both species averaged 11 metric tons per hectare, while plant Se levels were considered safe enough to utilize both forage species in animal feed rations. Water extractable levels of Se did not increase in soil to a depth of 90 cm, however, soil salinity and water extractable B levels increased. Increased salinity and B levels in the soil indicate that management of soil salinity and B will be necessary over time to sustain long-term reuse with poor quality water on these two potential forage species.
Technical Abstract: Water reuse is a proposed strategy for utilizing or disposing of poor quality drainage water produced in the westside of central California. This two-year field study evaluated the ability of two potential forage species to tolerate irrigation with water high in salinity, boron (B), and selenium (Se). The species used were: Sporobolus airoides var. salado (alkali sacaton) and Medicago sativa var. salado (alfalfa). Both species were furrow-irrigated with drainage effluent that had an average composition of sulfate-dominated salinity [(electrical conductivity (EC) of 6.2 dS m-1)] B (5 mg L-1) and Se (0.245 mg L-1). Annual dry mater yields averaged between 11 and 12 Mg ha-1 for both crops irrigated with effluent for two growing seasons. Plant concentrations of Se ranged from a low of 1.3 mg kg-1 in alkali sacaton to a high of 2.5 mg kg-1 in alfalfa, while B concentrations ranged from a low of 60 mg kg-1 in alkali sacaton to a high of 170 mg kg-1 in alfalfa. Chemical composition of the soil changed as follows from preplant to post-irrigation after two seasons with drainage effluent: EC from 2.78 to 6.5 dS m-1, extractable B from 1.9 to 5.6 mg L-1, and no change in extractable Se at 0.012 mg L-1 between 0-45 cm. Between 45-90 cm, EC values increased from 4.95 to 6.79 dS m-1, extractable B from 2.5 t0 4.8 mg L-1, and no change in extractable Se at 0.015 mg L-1. Increased salinity and extractable B levels in the soil indicate that management of soil salinity and B will be necessary over time to sustain long term reuse with poor quality water.