Bioaccumulation of salts by halophytes as a means of reclaiming saline soils.

摘要

Loss of soil productivity due to salinization remains an ecological and production challenge. The objective of this study was to quantify bioaccumulation and removal of Na from soils by halophyte species as a first step toward assessing the feasibility of using plants to restore salt-affected soils. After an extensive literature search, five halophytes (Allenrolfea occidentalis, Distichlis spicata, Atriplex canescens, Salicornia utahensis, and Suaeda moquinii) native to the arid southwestern U.S. were selected. Growth requirements, salt accumulation rates, and biomass production of each species were evaluated in replicated field studies using three levels of salinity (8, 16, and 32 dSm−1) and three irrigation frequencies (none, 25, and 15 MPa). Plausibility of harvest, use of the biomass, and amount of salt potentially removed from soils were also determined. Low field germination of Distichlis spicata and Salicornia utahensis, and the extremely slow growth rate of Allenrolfea occidentalis excluded them from much of the study. Suaeda moquinii had a mean biomass production of 126 g/plant over a 60-day period of growth and a mean Na accumulation of 74,625 mg kg−1 dry matter. Atriplex canescens had a mean biomass production of 253 g/plant over a 60-day growing period and a mean Na accumulation of 5,747 mg kg−1 dry matter. Both species contained N and C amounts that would make them quality forage plants. Neither biomass production nor salt accumulation were altered by irrigation in either species (α = 0.05). Both species significantly lowered the soil salinity. Suaeda moquinii has the most potential as a bioaccumulator due to high biomass production and high Na concentrations in its above-ground biomass.