中国科学院水利部水土保持研究所机构知识库

为研究工程扰动对黄土抗蚀性和抗冲性的影响，以兰州市城关区北山为研究区，选取1年填方样地（T1a）、5年填方样地（T5a）、7年挖方样地（W7a）和天然草地（C）4个样地采原状土样，在室内使用干筛-湿筛法测定土壤团聚体相关指标研究土壤抗蚀性，用抗冲槽研究土壤抗冲性，并分析了影响土壤抗蚀性和抗冲性的因素。结果显示，各样地表层（0—10 cm）土壤水稳性团聚体的平均质量直径（MWD_w）和＞0.25 mm团聚体占比[w_(δ>0.25)w]表现为C＞W7a＞T5a＞T1a，土壤团聚体破坏率（PAD）表现为T1a＞T5a＞W7a＞C，挖填方样地表层土壤水稳性团聚体颗粒分形维数（D_w）均值为2.82，C样地D_w为2.74，C样地表层土壤的抗蚀性显著强于挖填方样地；T5a和W7a样地中下层土壤（10—20 cm和20—30 cm）MWD_w和w_(δ>0.25)w显著低于表层土壤；各样地表层土壤抗冲系数W7a＞C＞T5a＞T1a，W7a和C样地的值较为接近。影响土壤抗蚀性与抗冲性的主要因素有土壤电导率、有机质和根系，土壤生物结皮也会影响土壤抗冲性。这些影响因素与挖填方样地搁置年限密切相关，即随着挖填方样地搁置年限增长，这些因素逐渐发生变化有益于受扰动土壤MWD_w和w_(δ>0.25)w的增加以及PAD的降低，其表层土壤的冲刷强度慢慢接近草地。工程扰动会显著降低黄土的抗蚀性和抗冲性，应当做好必要的水土保持措施以降低土壤侵蚀风险。

In order to study the influence of engineering disturbance on the soil anti-erodibility and soil anti-scourability of loess, taking Beishan, Chengguan District, Lanzhou City as the study area, undisturbed soil samples were collected from four sample plots: 1-year filled plot (T1a), 5-year filled plot (T5a), 7-year dug plot (W7a) and natural grassland plot (C). In the laboratory, the dry-wet sieve method was used to determine the soil aggregate related indicators to study the soil anti-erodibility, and the anti-scour trough was used to study the soil anti-scourability, and the factors affecting the soil anti erodibility and anti——scourability were analyzed. The results showed that the mean weight diameter of soil water-stable aggregates (MWD_w) and the proportion of aggregates ＞0.25 mm [w_(δ＞0.25)w] of the surface layer (0-10 cm) of each sample surface showed C＞W7a＞T5a＞T1a, the soil percentage of aggregates destruction (PAD) showed T1a＞T5a＞W7a＞C. The average of soil water stable aggregates fractal dimension (D_w) in the surface layer of dug and filled plots was 2.82, the D_w of C plot was 2.74. The anti-erodibility of the surface layer soil of the C is significantly stronger than that of the dug and filled site. The MWD_w and w_(δ＞0.25)w of the middle and lower soil (10-20 cm and 20-30 cm) of the T5a and W7a plots were significantly lower than those of the surface layer soil. The surface soil anti-erosion coefficient of each sample showed W7a＞C＞T5a＞T1a, and the values of W7a and C sample plots were relatively close. Soil electrical conductivity, organic matter and root system are the main factors affecting soil anti-erodibility and soil anti-scourability，in addition, soil biological crusts can also affect soil anti-scourability. These factors are closely related to the shelving years of dug and filled plots. Which means, these factors gradually change as the shelving time of dug and filled plots increases, which is beneficial to the increase of MWD_w and w_(δ＞0.25)w，and the decrease of PAD of disturbed soil, and the scouring intensity of surface soil is close to that of natural grassland. Engineering disturbance will significantly reduce the soil anti-erodibility and soil anti-scourability of loess, and necessary water and soil conservation measures should be taken to reduce the risk of soil erosion.