论文部分内容阅读
植被的土壤保持功能评估是生态安全研究中的重要内容之一。现有研究中缺乏较大尺度、较高精度的土壤保持估算。基于通用水土流失方程与年尺度风蚀预报方程,估算西北地区土壤现实侵蚀量与潜在侵蚀量,得出植被土壤保持物质量与价值量,并进行土壤保持效益分区。结果表明:植被土壤水蚀保持量高值集中在秦巴山区一带,其值超过5000t/(hm2a);青海东南部三江源地区植被土壤水蚀保持量在(500～2000)t/(hm2a);而1万t/(hm2a)以上的植被土壤风蚀保持量样本很少,集中在天山、西祁连山、三江源三大区域;沙漠内部几乎不发生植被土壤保持作用。单位面积价值量大于2亿元/km2的像元几乎全部位于陕南和陇东南的秦巴山区中。黄土高原土壤保持价值量也多在1000万元/km2以上。最后统计土壤保持价值总量,进行县域单元的土壤保持生态效益分级,并阐述了4种县域生态建设定位。
Vegetation assessment of soil conservation is one of the most important parts of ecological safety research. The existing research lacks the large-scale and high-precision soil conservation estimation. Based on the general equation of soil and water loss and annual scale wind erosion prediction equation, the actual soil erosion and potential erosion in Northwest China were estimated, and the quality and value of vegetation soil retention were obtained, and the soil conservation benefit was divided. The results showed that the high values of water erosion in vegetation were concentrated in the area of Qinling-Bashan Mountains with the value exceeding 5000 t / (hm2a); the soil erosion of the vegetation in the Three-River Source Region of southeastern Qinghai Province was (500 ~ 2000) t / (hm2a) There are few samples of soil erosion maintaining amount above 10 000 t / (hm2a), which are concentrated in three major areas of Tianshan Mountains, Western Qilian Mountains and Three Rivers. There is almost no vegetation retention in the desert. Pixels with a unit area value of more than 200 million yuan / km2 are located in almost all of the Qinba Mountains in southern Shaanxi and Longdongnan. Loess Plateau soil conservation value of more than 10 million yuan / km2. Finally, the total amount of soil conservation value is counted, and the ecological benefit classification of soil conservation unit is carried out. Four kinds of ecological construction positioning in county area are also described.