京津风沙源治理工程区LUCC及土壤风蚀强度动态遥感监测研究

Study on Dynamic Remote Sensing Monitoring of LUCC and Soilwind Erosion Intensity in the Beijing-Tianjin Sandstorm Source Control Project Region

以遥感手段监测京津风沙源治理工程区土地利用/覆盖变化及土壤风蚀强度,分析了工程区LUCC及土壤风蚀时空格局特征及关系。结果表明:工程实施前后,LUCC及土壤风蚀强度差异明显。近30a,LUCC过程主要表现了由耕地开垦向生态退耕还林、草转变,伴随生态恢复和沙化有效抑制态势;耕地总体表现出先增加后减少态势,耕地面积1990～2000年增加面积是2000～2015年减少面积的1.9倍;林地总体呈增加态势;2000～2015年耕地转化为林地和草地面积分别为446.1km2和1 129.3km2,西部最为明显;建设用地面积扩张明显;未利用地呈减少趋势,转换类型以沙地向草地转化为主,面积为1 493.1km2。京津风沙源治理工程区土壤风蚀侵蚀模数整体呈下降趋势,生态工程实施后改善趋势明显(P<0.01);总体上,东部、南部地区以高覆盖、中覆盖草地类型为主的地区土壤风蚀量小;浑善达克沙地治理区土壤风蚀量较大,但总体呈减少趋势。不同土地利用/覆盖类型对土壤风蚀强度影响较大,土壤风蚀模数依次为沙地>低覆盖度草地>中覆盖度草地>旱地>灌木林>水田>高覆盖度草地>其他林地>疏林地>有林地;低覆盖度向高覆盖度草地类型转化有效抑制土壤风蚀量(减少66.12%),植被覆盖度的增加有效降低土壤风蚀模数;沙地周边区域,高/中覆盖度向低覆盖度草地类型转换过程中,土壤风蚀量呈增加(58.26%)态势,草地转化为沙地、旱地土壤风蚀量增加。

The Land Use/Cover Change（LUCC） and soil wind erosion intensity of the Beijing-Tianjin sand-storm source control project region were monitored by remote sensing.The spatial and temporal patterns of LUCC and soil wind erosion in the project region were analyzed.The results showed that there was significant difference in LUCC and soil erosion intensity before and after the project was implemented.In the re- cent 30 years,the LUCC process mainly manifested the change from cultivated land reclamation to ecologi- cal conversion of farmland to forest and grass, with the ecological restoration and desertification effectively inhibited.The overall arable land showed an increase and then decreased.The area of arable land increased from 2000 to 2015 ,the area of cultivated land converted to forest and grassland was 446.10 km^2 and 1 129. 32 km^2 ,with the most obvious in the west;the area of land for construction expanded obviously;the trend of unutilized land decreased significantly The type of conversion is dominated by grassland conversion to grassland with an area of 493.12 km^2.The erosion-mitigating modulus of soil erosion in the project region with wind-blown sand control decreased overall, especially after the implementation of ecological engineering （p〈0.001）.The eastern and southern areas are covered with high-coverage grassland and soil wind erosion in the area with the main type is small,Soil wind erosion in the Hunshandake sandy land is larger,but the overall trend is decreasing.Different land use/cover types have a greater impact on soil wind erosion in- tensity.The order of soil wind erosion modulus is Sandy land〉 Sparse grass〉 Moderate grass）dryland〉 Shrub〉Paddy〉Dense grass〉 Other woods〉 Sparse woods〉 Forest; The conversion of low coverage to high coverage grassland types effectively inhibited soil erosion （-66.12%）,and the increase of vegetation coverage effectively reduced soil erosion.The soil wind erosion increased （58.26%） in the surrounding area of sandy area, the soil wind erosion increasedduring the conversion process of low coverage grassland type, and the grassland was converted into sand,and the wind erosion in the dry land increased.