Metagenomic analysis reveal the phytoremediation effects of monocropping and intercropping of halophytes Halogeton glomeratus and Suaeda glauca in saline soil of Northwestern China

Abstract

Aims: Planting halophytes is a widely used method of phytoremediation for saline soils. The succulent halophytes Halogeton glomeratus and Suaeda glauca are widely used for remediation of saline soil in the arid region of Northwestern China. However, whether intercropping of H. glomeratus and S. glauca can increase the improvement effect for saline soil is yet to be proved. Materials and methods: Therefore, this study analyzed three phytoremediation planting modes: monocropping of H. glomeratus (Hg), monocropping of S. glauca (Sg), and H. glomeratus and S. glauca intercropping (Hg||Sg). These were applied in field experiments, with biomass and soil physicochemical properties measured for each treatment, and the mechanism was analyzed using macrogenomics. Results: After harvesting the halophytes after one season, the Hg treatment had the highest dry biomass and soil total dissolved salt content was reduced; correspondingly, soil pH were decreased and soil organic matter content were increased. The results showed that Actinobacteria, Acidobacteria and Proteobacteria were the dominant phylum under the four treatments. This suggests that Hg treatment was more capable of producing microorganisms favorable to saline soil remediation. Conclusions: Thus, H. glomeratus monocropping is a more effective phytoremediation strategy for saline soil in the dry zone of Northwestern China.