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Water reuse is a proposed strategy for utilizing or disposing of poor quality drainage water produced in the westside of central California. This 2-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: Sporobulus airoides var. salado (alkali sacaton) and Medicago sativa var. salado (alfalfa). After first year establishment with good quality water (<1 dS m–1), the two 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). Both crops were clipped monthly from June to October of each year. Total dry matter 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 and 45 cm. Between 45 and 90 cm, EC values increased from 4.95 to 6.79 dS m–1, extractable B from 2.5 to 4.8 mg l–1, and no change in extractable Se at 0.016 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. 相似文献
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