| How to reverse the degradation process and rehabilitate the due productivity in the ecological system of sar(?)land is one of the key and urgent issues in the construction of ecological environment. From 2002 to 2003, two measures of Caragana intermedia stands of stripe planting and natural rehabilitation of vegetation were been the research object, then positioning observations and studies on their soil physical-chemical features, soil moisture and plant community characters.The conclusions of the studies mainly include the fallowings:1. After the establishment of Caragana artificial stands, the physical-chemical features of the soils were significantly improved. Compared with the untreated of natural grassland, (1) the content of fine sand (φ 0.2~0.02 mm) at soil profile 0-100 cm in Caragana stands increased by 11.33-13.67%. (2) the content of water-stable aggregates (>0.25 mm) and the rate of soil structure damage was in an order of 3330 Caragana/ha < natural grassland < 2490 Caragana/ha < 1665 Caragana/ha. (3) the bulk density of soils 20 cm under the ground at Caragana stands was better than at natural grassland, and the total porosity at Caragana stands at soil profile 0-60 cm was higher than natural grassland. (4) at soil profile 0-80 cm, the content of total nitrogen, fast-effect phosphorous and fast-effect potassium was significantly higher than natural grassland, and the activity of urase, invertase and catalase was improved.2. The establishment of Caragana artificial stands changed the regime of soil moisture at the degrading sandland. (1) the seasonal changes of soil moisture at different densities of Caragana stands approached to similar tendency of moisture dynamics. However, the sequencing of soil moisture and water reserve was 1665 Caragana/ha > 2490 > Caragana/ha > natural grassland > 3330 Caragana/ha. (2) artificial Caragana stands lowered the low-limit of the available soil moisture at the degrading sandland. In terms of wilting moisture, the sequencing was 1665 Caragana/ha < 2490 Caragana/ha < 3330 Caragana/ha |
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