干旱区生态环境知识资源中心

The complicated desert vegetation pattern and its links to soil conditions in the Manas River basin where the natural landscape and human land-use history are representative for NW China and even central Asia are quantitatively investigated in this study. Vegetation and soil of 47 remnant desert and 22 cropland stands along the Manas River were sampled. Soil features, including Total Organic Carbon (TOC), total and individual ( HCO3-, CO32-, Cl-, SO42- , K+, Na+, Ca2+, Mg2+) salt content, and physical components of both remnant desert and cropland stands were analyzed in a laboratory. In total, eight types of desert and lowland marsh communities are distinguished. Topographical conditions are found to strongly affect soil features. The topsoil is also distinguishable from the subsoil, particularly in clay content. Statistical analyses demonstrate that both silt percentage and total salt content in the soil are significant for the distribution of plant communities. Discriminant functions for the main desert and lowland marsh types were established based on their subsoil features, with accuracy up to 83%. The vegetation patterns prior to massive cultivation of 22 cropland plots were reliably interpreted from the cropland subsoil features using these discriminant functions. Twenty of them coincide very well with topological conditions, place names and records in literature, further confirming that the subsoil features have not substantially changed in the shifting from desert to cropland.