Dynamics of soil enzyme activity in the rhizosphere of desert halophyte

A rhizobag experiment was conducted in desert solonchak and cultivated gray desert soils to investigate nutrient content and soil enzyme activity in the rhizospheres of six desert halophytes. The results show significant increase in total N and decrease in total P in the rhizosphere in comparison with bulk soil. Available N and P have inverse dynamics in that while available N decreases, available P increases, except for Phragmites communis Trin. Available N deficit is highest while accumulated available P is lowest in Salsola nitraria Pall among the six halophytes. Analysis for sucrase, protease, urease, neutral phospherease, alkaline phosphcrease and catalase activity as well as its relationship with soil nutrient content shows inverse dynamics for sucrase, protease and catalase in both soil rhizospheres. In solonchak soils, the activity of the three soil enzymes in the rhizosphere is generally higher than in bulk soils while that in cultivated gray-desert soils are lower. In solonchak soils, the activity of alkaline phosphcrease, catalase and invertase is significantly related with soil nutrient content, which could be a strong indicator of soil nutrient status. The results suggest significant impact of halophyte on enzyme activity in desert solonchak.