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甘肃中部黄土沟壑区的西小河流域,以前由于长期水土流失,土壤肥力很低,“四料”(燃、饲、肥及木料) 俱缺,给当地人民生活带来极大困难。1979年以来,该区采取以造林种草为主的生物措施治理水土流失。目前森林覆盖率已由原来的4.6%提高到13.4%,林草总覆被率达21.9%。“四料”俱缺的局面已得到初步缓和,水土流失逐渐减轻,环境条件得到明显改善。为探讨在西小河流域林种配置的最佳效益,我们于1984年对同龄小意杨(P.
Due to the long-term water and soil loss and low soil fertility, the “four materials” (burning, feeding, fertilizing and timbering) have brought great difficulties to the local people’s lives in the West Xiao River Basin in the loess gully area of central Gansu. Since 1979, the area has adopted biological measures such as afforestation and grass planting to control soil and water loss. At present, the forest cover rate has been increased from 4.6% to 13.4%, and the total forest cover coverage rate has reached 21.9%. The “four materials” deficiencies have been initially alleviated, soil and water loss gradually reduced, and environmental conditions have been significantly improved. In order to explore the best benefits of forest species allocation in the West Xiao River Basin,