不同坡度及坡向条件下的土壤侵蚀特征研究——以淮河北部支流低山丘陵区为例

Soil Erosion Characteristics of Different Slope Gradients and Aspects——Taking Low Mountain and Hilly Areas in North Branches of Huaihe River as an Example

借助RS和GIS技术获取研究区土壤侵蚀的相关影响因子,运用RUSLE土壤侵蚀模型,计算研究区土壤侵蚀模数,进行侵蚀强度分级,并探讨不同坡度和坡向条件下的土壤侵蚀特征.结果表明,研究区平均土壤侵蚀模数为1 173.755 t/（km2·a）,年侵蚀总量约9.56×107t;约96％的区域为微度侵蚀;轻度以上侵蚀主要发生在西部和北部的低山丘陵区,侵蚀土壤面积占总面积的3.32％,但泥沙流失量的比重为72.024％,是防治水土流失的关键区域;随着坡度的增加,侵蚀面积呈先减小后增大而后又减小的趋势,8°～15°坡度带是土壤侵蚀状况的转折点;不同坡向条件下,土壤侵蚀面积由大到小的顺序为半阳坡、阳坡、阴坡和平地,半阳坡侵蚀面积约占总侵蚀面积的50％.

Based on to RS and GIS techniques, the primary factors affecting the soil erosion were calculated through the RUSLE model of soil erosion. The total amount and degree of soil erosion together with the analysis of different slope gradients and aspects were studied. The results showed that annual average soil erosion modulus was 1 173.755 t/（km2-a） and the erosion amount was 9.56×107 t, with 96% study area in tiny degree erosion. The light or high degree eroded area was mainly distributed in the low mountain and western and northern hilly areas, occupying only 3.32% of total study area with 72.024% of sediment losing. It was key area for protecting soil erosion. With the increase of slope gradient, the erosion area was reduced firstly, then increased and decreased finally. The slope gradient of 8° to 15° was the turning point for the soil erosion. Under different slope aspects, the soil erosion areas from high to low were half sunny slope, sunny slope, shady slope and fiat slope. The erosion area of half sunny was 50% of total eroded area.