Dynamic change of salt contents in rhizosphere soil of salt-tolerant plants

Secondary salinization of soil is a major limiting factor for agricultural sustainability development in irrigated agriculture in arid and semi-arid regions. At present, the problem of soil salinity is further deteriorating in inland arid regions as the dry lands have become irrigated fields, which caused the substantial rise of groundwater table. The majority of comparative studies suggested that phytoremediation (plant-assisted approach) is more effective in the amelioration process in recent years. Rhizosphere is an important interface in substance exchange and energy transformation between plants and soil. Affected by physiological activities of plant roots, there is a marked difference in physichemistry properties between the rhizosphere soil and bulk soil. Based on a calcareous salt-affected soil in the irrigated region of Qingwangchuan, Gansu, a rhizobag experiment was conducted on four salt-tolerant plants to investigate dynamic changes of pH, EC (Electrical Conductivity) and salt ions in the rhizosphere and bulk soil, and to compare the differences between them at the different plant growth stages. The results showed that pH, EC and concentrations of six major salt ions in four tested plants decreased with the extension of incubation days. There was significantly (P