Soil Properties under Major Halophytic Vegetation Communities in Arid Regions

Soil physical, chemical, and biological properties of seven desert halophytes（Kalidium foliatum, Achnatherum splendens, Leymus secalinus, Phragmites australis, Karelinia caspia, Tamarix ramosissima, Atriplex tatarica） were investigated in saline-sodic badlands of the Hexi Corridor, Gansu Province, China. The results showed that sampled soils were generally infertile and characterized by low levels of organic matter, available nitrogen, phosphorus, copper, manganese, and zinc as well as microbial communities with dominant bacteria supporting native desert halophytes. Available potassium and iron were sufficient in the study sites. With increasing soil layer depth, the concentrations of organic matter, available nitrogen, potassium, manganese, copper, bacteria, and actinomyces in the soil decreased significantly（P〈0.05）, while the concentrations of moisture, available iron, and zinc in the soil increased significantly（P〈0.05）. The contents of moisture, total salt, organic matter, available nitrogen, potassium, iron, manganese, zinc, copper, bacteria, and actinomyces showed significant seasonal variations（P〈0.05）. All these variables except bacteria and actinomyces were the greatest in summer and the lowest in spring. The redundancy analysis revealed that total salt, organic matter, available potassium, and copper were positively correlated with vegetation coverage. K. foliatum community was the constructive or dominant species in the desert community for the biological control of soil salinization.