晋北沙漠化地区土壤风蚀动态及防治效果

目的]对晋北沙漠化区土壤风蚀状况及空间差异进行研究,以期为区域土地退化和京津风沙源治理工程的效益评估提供科学依据。方法]基于耕地和林草地不同地表类型的土壤风蚀模型,逐像元地计算2001—2014年晋北沙漠化地区土壤风蚀状况及空间差异。结果](1)2001—2014年晋北沙漠化区的平均土壤风蚀模数达到4.67t/(hm~2·a),处于轻度风蚀状态。区域分布上,北部区域风蚀状况明显高于南部。(2)研究区2001,2005,2010和2014年的平均土壤风蚀模数分别为6.83,3.89,4.36和2.55t/(hm~2·a);土壤风蚀总量分别为2.09×10~7 t,1.19×10~7 t,1.31×10~7 t和7.65×106 t。(3)晋北沙漠化地区植被覆盖度提高和风力减弱是区域土壤风蚀强度削弱的主要原因。研究发现风力作用的减弱贡献率约为77.7%,而植被覆盖度的提高的贡献率为22.3%。结论]晋北土壤风蚀状况空间差异较大,风速减弱是导致区域土壤风蚀削弱的主要原因。晋北沙漠化地区植被覆盖度尚未恢复到良好的状态,生态工程建设还需进一步实施,生态工程实施的成果需加强保护。

Dynamics and Control Effect of Soil Wind Erosion in Desertification Region of Northern Shanxi Province

Objective] Dynamics of soil wind erosion in the desertification region of Northern Shanxi Province were analyzed to provide some supports for the prevention of land degradation and the benefit assessment of sand source control engineering for Beijing-Tianjin Cities.Methods] Based on different types of surface soil erosion model, we studied the dynamics and spatial variability of soil wind erosion for each pixel in the desertification region of Northern Shanxi Province from 2001 to 2014 and then quantitatively evaluated the effects of different factors on regional soil wind erosion control.Results] (1) Average annual soil wind erosion modulus in the desertification region of Northern Shanxi Province in 2001-2014 was 4.67 t/(hm²·a), which is in a state of mild deflation. In terms of regional distribution, the state of wind erosion desertification in the north of that region was more serious than that in the south. (2) The average soil erosion modul in 2001, 2005, 2010 and 2014 were 6.83, 3.89, 4.36 and 2.55 t/(hm²·a), respectively. And the total amounts of soil erosion were 20.90 million ton, 11.88 million ton, 13.10 million ton and 7.65 million ton, respectively. (3) The improvements of vegetation coverage and wind weakening were the main causes of decline of regional soil wind intensity in the desertification region of Northern Shanxi Province. The study found that the contribution rate of wind effect weakening was about 77.7% for the decrease of wind erosion, while the contribution rate of increase of vegetation coverage was 22.3%.Conclusion] The soil wind erosion change varied remarkably in spatial domain. Wind weakens is the main cause of regional soil wind intensity weaken in Northern Shanxi Province desertification region. The vegetation coverage in Northern Shanxi Province desertification region has not been restored to a good condition. This indicates that the implement of ecological engineering should be carried out and the effects of ecological project should be protected.