Abstract:

An evaluation on the shelter belts in a new oasis in Ulanbuhe Sands was carried out at the Dengkou County in western Inner Mongolia.The forest coverage in the study site increased from zero to 26.4% after the land development due to the establishment of shelterbelts.The result showed that:a) the crop yield per hectare inside the shelterbelts is 45.77% higher than that of outdside for wheat, 155.71% for seedsmelon, and 25.0% for beet; b) the new farmlands begin to gain at the sixth year after the establishment of shelterbelts, and all the investments can be take back at the tenth year with a profit of 22, 217 RMB Yuan; c) the annual sand-dust storm days inside the shelterbelts is 56.5% lower than that of outside, 56.8% for annual sand-blowing days, 63.9% for annual dust devil days, 6.5% for annual gale days, and 38.6%~63.2% for annual average wind velocity; d) there are 10 bacteria species in seven genera, 14 actinomyces species in one genus, and two fungus gnera in the developed land, while only four bacteria specie in four genera, eight actinomyces species in one genys, and no fungus in the desert lands; Comparing with the desert land, the soil salt content in the developed land is decreased by 31.6%, 13.6%, and 16.6% at soil layer Ⅰ (2 ~10cm), Ⅱ (10~30cm), and Ⅲ (30~100cm) respectively, and the pH is decreased by 0.88; e) the establishment of shelterbelts has greatly improved the habitats for wild animals and birds, which increased at a rate of 100%~400% in 1994; f) the human carrying capacity is increased by 33.1 times after the land development and the income per capita is 1356 RMB Yuan in the study year comparing to 98 RMB Yuan before the land development.

Key words: Arid zone, Evaluation, Shelterbelt, Ulanbuhe Sands