指纹法研究花岗岩区典型崩岗小流域悬浮泥沙来源

Fingerprinting Suspended Sediment Sources in a Typical Collapsing Hill Watershed in the Granitic Region

为研究花岗岩区典型崩岗小流域内悬浮泥沙来源,以安溪县龙门镇崩岗侵蚀小流域为研究对象,在4种土地利用类型(侵蚀林地、茶园、耕地和崩岗侵蚀区)中共采集85个泥沙源地土样,同时在河道布设采样器收集降雨后侵蚀悬浮泥沙。通过分析样品中的34种指纹因子,运用复合指纹法筛选出最佳指纹因子组合,并计算出各泥沙源地的泥沙运移规律。结果表明:不同泥沙源地悬浮泥沙中同种指纹因子存在显著差异,利用Kruskal-Wallis检验和多元判别筛选出Ca、Li、Sn、K和Ba为最佳指纹因子组合(累积贡献率大于90%);同时利用多元混合模型得出茶园的悬浮泥沙相对贡献百分比为33%,耕地为27%,侵蚀林地和崩岗侵蚀区均为20%,且混合模型优度拟合检验值为0.89。进一步分析表明,降雨对崩岗侵蚀区的影响最大,茶园和崩岗侵蚀区单位面积产生悬浮泥沙量明显高于其他两个源地,说明崩岗侵蚀区和茶园是花岗岩区崩岗小流域中需要采取防治措施的重点。

To analyse suspended sediment sources in a typical collapsing hill watershed in the granitic region, a collapsing hill watershed in the Longmen town, Anxi County, was selected as the research object. 85 soil samples from four kinds of sediment source （erosive woodland, tea plantations, cultivated land, and the erosive area of a collapsing hill area） were collected, in the meantime, erosion suspended sediment in the sampler in the channel was also collected. 34 kinds of fingerprint factors of the samples were analyzed, the best combination of fingerprint factors was screened, from different sources were figured out. The results and the migration regularities of the sediments derived showed that there were significant differences in the same fingerprint factors of the suspended sediments derived from different sources. By using the Kruskal- Wallis test and multivariate discriminant, the combination of Ca, Li, Sn, K and Ba was screened as the best combination of fingerprint factors, of which the cumulative contribution rate was more than 90%. The relative contribution of suspended sediment was approximately 33% by tea plantations, 27%by cultivated land, and 20% by erosive woodland and collapsing hills. The goodness-of-fit test value of the Hybrid model was 0.89. Further analysis showed that the influence of rainfall on collapsing erosion was the greatest. Suspended sediment yields of collapsing erosion and tea plantations other sediment sources, indicating that the prevention collapsing erosion and tea plantations in this study area. per unit area were obviously higher than those of and control measures should be focused on the