贵州省不同地貌形态类型土壤侵蚀强度变化的定量分析

Quantitative Analysis on the Soil Erosion Intensity Change in Different Morphological Types of Guizhou Province

如何揭示不同地貌形态类型区土壤侵蚀强度变化,尤其是在生态环境比较脆弱的喀斯特区域,是地方生态保护战略实施亟需研究的关键问题之一。本文基于ALOS、ZY-3、GF-1、Landsat和GDEMV2遥感影像数据,以及2762条野外采样验证数据,参照国家在喀斯特与非喀斯特地区土壤侵蚀不同分类标准,实现10 m×10 m分辨率的贵州省2010年和2015年土壤侵蚀空间信息数据提取。进而结合贵州省地貌数据,通过构建贵州省土壤侵蚀的时空分析模型,实现对不同地貌形态类型,尤其是喀斯特区域和非喀斯特区域的土壤侵蚀强度的时空变化进行定量分析。结果显示:在2010—2015年,贵州省中—高海拔区域土壤侵蚀变化的动态度高于低海拔区域,土壤侵蚀强度总体呈下降趋势,下降总面积达6468.13 km^2。喀斯特区域的土壤侵蚀变化广度高于非喀斯特区域的土壤侵蚀变化广度,而且变化趋势基本上是从高一级的侵蚀强度向低一级的侵蚀强度变化。高盆地、中山、高中山土壤侵蚀强度减弱趋势明显高于其他地貌类型的趋势,但高中山仍是喀斯特与非喀斯特区土壤侵蚀增强变化较为明显的区域。这说明自21世纪以来,在贵州喀斯特区域实施的生态修复工程和生态环境保护政策在土壤侵蚀防治过程中发挥了主导性作用,在今后贵州省进行土壤侵蚀防治的过程中,除了喀斯特区域的防治外,还需要同时注意非喀斯特区域的防治。

Quantifying the changes of soil erosion intensity across different geomorphological types is one of the key issues that need to be explored in the field of soil and water conservation,especially for the karst region where the ecological environment is relatively fragile.According to different classification criteria of soil erosion intensity in karst and non-karst areas of China,we generated the spatially explicit soil erosion data at a resolution of 10 m×10 m in Guizhou Province combining multi-resolution remote sensing data,i.e.ALOS,ZY-3,GF-1,Landsat,and GDEMV2,and 2762 field samples in 2010 and 2015.We analyzed the spatial-temporal changes of soil erosion intensity in karst and non-karst area of Guizhou Province based on the spatial distribution of soil erosion estimates and the geomorphological type data of Guizhou Province.The results show that soil erosion intensity showed a decreasing trend with the total area of soil erosion decreased by 6468.13 km^2 in Guizhou Province from 2010 to 2015.The total area of decreasing soil erosion intensity in karst area was larger than that in nonkarst area,while the decreasing amplitude of soil erosion intensity in extremely intense and severe erosion karst area was smaller than that in non-karst area,which indicated a higher difficulty of soil erosion restoration in extremely intense and severe erosion area in karst area.Moreover,the decrease of soil erosion intensity in high-altitude areas was larger than that in the low-altitude areas.The decreasing soil erosion intensity in high basins,middle mountains,and high mountains was more obvious than that of other geomorphological types,though high mountains in karst and non-karst areas were still the obvious areas of increasing soil erosion.In our study,the larger decrease in soil erosion intensity in karst area than non-karst area might be due to the ecological restoration projects and water soil conservation polices carried out in karst area,especially in the western of Guizhou Province during 2010-2015.In future,the soil erosion in non-karst area should also be paid attention by local government.