宁杭高铁不同乔木覆盖下侵蚀强度季节差异

高铁线路边坡具有跨度大、跨地貌多、治理耗时长的特点,以宁杭高铁江苏段为例,宁杭高铁已正式运营7年,自然恢复条件下土壤流失现状的调查和研究可以为水土流失的综合治理提供指导意见。对2018年3月—2019年2月典型样地土壤抗冲性、抗剪性、土壤理化性质、侵蚀强度进行了季度监测。选取4处扰动后的缓地样地,以及相邻处的原状样地,样地植被类型主要为刺槐(Robinia pseudoacacia L.)、马尾松(Pinus massoniana Lamb.)、榉树(Zelkova serrata(Thunb.)Makino)、女贞(Ligustrum lucidum),研究表明:①全量元素和有机质变化趋势呈现春夏渐增、秋冬渐衰的趋势。马尾松、刺槐养分水平较高,女贞、榉树养分水平偏低,但养分含量稳定性较优良;②抗冲刷指数与抗剪性指标全年变化趋势为春夏季下降,秋冬季上升,马尾松和刺槐林分抗冲抗剪性较为优良;③夏季土壤侵蚀强度高于春季、秋季、冬季,马尾松和刺槐林分土壤侵蚀强度较小;④土壤含水率、降雨量、降雨强度、全磷含量、抗冲刷系数、抗剪性、草本植被覆盖度和土壤侵蚀强度具有较强的相关性,降雨强度、含水率和日最大降雨量、有机质、覆盖度、抗剪性和抗冲刷系数对土壤侵蚀的贡献率较高。

Seasonal difference of erosion intensity under four tree covers on high-speed rail slope

In order to accurately monitor the seasonal variation of soil erosion intensity and soil site conditions along the high-speed railway slope, the seasonal variation law and difference of soil erosion intensity under natural restoration conditions were compared and analyzed. The erosion resistance of typical tree sample plots from March 2018 to February 2019 was studied. The shear resistance, soil physical and chemical properties and erosion intensity were monitored quarterly. Four slow plots were selected. The main vegetation types were Robinia pseudoacacia L., Pinus massoniana Lamb., Zelkova serrata (Thunb.) Makino and Ligustrum lucidum. Typical plots were selected in the sample plots, and the light conditions and experimental points of vegetation growth were selected to determine organic matter. Content, total phosphorus content, total potassium content, rainfall, impact resistance, shear resistance and erosion modulus were analyzed, and regression equation was established, and seasonal mean test was carried out. The results show that: (1) The variation trend of total elements and organic matter is increasing in spring and summer, and declining in autumn and winter. The nutrient levels of Pinus massoniana and Robinia pseudoacacia are higher, the nutrient levels of Ligustrum lucidum and Beech are lower, but the stability of nutrient content is better; (2) The trend of annual variation of scour resistance index and shear resistance index is descending in spring and summer, rising in autumn and winter, and the scour resistance and shear resistance of Pinus massoniana and Robinia pseudoacacia stands are better; (3) The degree of soil erosion in summer is higher than that in summer. In spring, autumn and winter, the soil erosion degree of Pinus massoniana and Robinia pseudoacacia stands is relatively small; (4) Soil moisture content, rainfall, rainfall intensity, total phosphorus content, erosion resistance coefficient, shear resistance, herbaceous vegetation coverage and soil erosion modulus have strong correlation, rainfall intensity, moisture content and daily maximum rainfall, organic matter. The contribution rates of quality, coverage, shear resistance and scour resistance coefficient to soil erosion are higher.