贵州喀斯特区典型小流域坡面土壤侵蚀与主要影响因子的响应

Response of Soil Erosion to Main Influencing Factors on Hillslope of Typical Watersheds in Guizhou Karst Area

为探讨贵州喀斯特区不同土地利用方式、地形及降雨等因子对坡面土壤侵蚀的响应,采取野外径流小区定位观测法,以贵州省龙里县羊鸡冲小流域及毕节市石桥小流域为研究对象,开展了典型喀斯特坡面土壤侵蚀观测试验。结果表明:龙里羊鸡冲小流域坡面3种不同土地利用方式中,撂荒地因植被的快速恢复,土壤侵蚀程度最轻,2014年全年土壤侵蚀量仅为4.7t/km^2,林地次之,91.3t/km^2,而坡耕地侵蚀程度最为严重,达629.5t/km^2,进一步的差异显著性检验表明,3种坡面土地利用方式土壤侵蚀在0.05水平上差异显著(p<0.05);石桥小流域地形因子对土壤侵蚀响应关系表现为随坡长的增加土壤侵蚀呈增加趋势,但未达显著水平(p>0.05);降雨量同土壤侵蚀关系密切,在0.01水平上呈显著正相关(p<0.01),且以二次多项式拟合曲线效果最好(R^2>0.5)。

To reveal the response of soil erosion on hillslope to land use patterns,terrain and rainfall in Guizhou karst area,Yangjichong small watershed in Longli,Shiqiao small watershed in Bijie were took as the research areas to carry out the experiment of soil erosion.The results showed that among the three land use patterns in Yangjichong small watershed,soil erosion modulus of abandoned land was the lowest,and merely 4.7 t/km^2 in 2014,and it was 91.3 t/km^2 on the forestland due to the rapid vegetation restoration,it was the highest on the farmland,and reached to 629.5 t/km^2.Differentia tests showed that the soil erosion rates on forestland,abandoned land and farmland were significantly different at 0.05 level(p<0.05).The effect of terrain factor on soil erosion showed that the soil erosion amount increased with the increase of slope length,but the effect of slope length on soil erosion was not significant(p >0.05).The analysis on correlation between rainfall and soil erosion indicated that soil erosion was positively correlated with rainfall at 0.01 level(p<0.01),and the quadratic polynomial fitting curve can perfectly describe the relation between soil erosion and rainfall(R^2 >0.5).