Soil fertility, chemical properties, and pollutant removal efficiency of Salicornia europaea in response to different times and duration of wastewater irrigation

摘要

Halophytes are the good candidates in coastal saline areas which could be irrigated with wastewater. The purpose of this study was to evaluate the soil–water–plant system under control and wastewater irrigation (containing toxic elements and organic matter) at three durations (vegetative, flowering, and reproductive stages) and two exposure times (2 and 4 days in each stage). The results obtained in the experimental tests for wastewater irrigation indicated that the Salicornia is efficient for the removal of chemical oxygen demand (61%), biochemical oxygen demand (74%), total suspended solids (47.6%), and ammoniacal nitrogen (64%) at the reproductive stage. At the same time, the average nitrate concentration increased to 51.3 mg L−1 with more solids. Regardless of wastewater irrigation duration, irrigation with wastewater significantly increased organic matter, nitrogen, phosphorus, and potassium of the soil. The Mg2+ and Ca2+ contents in the aboveground biomass of the plants were also high ranged from 0.58 to 1%, and 0.43 to 0.68 mg g−1 DW, respectively. All the exchangeable cations other than Na+ were higher for wastewater irrigation at the flowering stage. Plants maintained noticeably higher Ca2+/Na+ and K+/Na+ ratios in the roots than those in the shoots except for 4 days after the reproductive stage. S. europaea is well adapted to grow in wastewater irrigation and can tolerate hypoxic conditions through improving water and soil quality.