Feasibility of Irrigating Pickleweed (Salicornia bigelovii Torr) with Hyper-saline Drainage Water
2008
Grattan, S. R. | Benes, S. E. | Peters, D. W. | Diaz, F.
Reuse of drainage water (DW) for irrigation reduces the volume of DW requiring treatment or disposal. We conducted a greenhouse study to evaluate the performance of the halophyte Salicornia bigelovii Torr. when irrigated with hyper-saline DW and seawater (SW) treatments, ranging from 1/3 strength to full strength (18–49 dS m⁻¹), in a sand-culture system. Results indicate that Salicornia grows well over the entire range of iso-osmotic SW and DW salinity treatments. Moreover, when boron (B) was added to SW treatments to concentrations equivalent to that of corresponding 1/3- and 2/3-strength DW treatments (i.e., 9 and 17 mg L⁻¹), growth was not affected, and tissue B concentrations were <150 mg kg⁻¹ dry wt. However, when plants were irrigated with synthetic DW where B was reduced to solution culture levels (0.5–1.0 mg L⁻¹), plants generally performed worse than when irrigated with actual DW high in B at the same salinity level. Evapotranspiration (ET) rates exceeded that lost from an evaporation pan from 1.5 to 2.5 times. Using a method accounting for changes in the isotopic signature of water in the reservoir due to evaporation, we estimated that high ET rates were due primarily to high transpiration rates (>78% of ET). The salt content in the tissue was very high (ash content 43–52%), but ionic composition in the shoot tissue reflected that of the treatment water used to irrigate the plants. These data indicate that hyper-saline DW, characteristic of California's San Joaquin Valley, can be used to irrigate Salicornia and substantially reduce drainage volumes.
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