宁杭高铁不同乔木覆盖下侵蚀强度季节差异

Seasonal Difference of Erosion Intensity under Four Tree Covers on High-speed Rail Slope

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。

The slope along a high-speed railway line features long span,multi-spanning geomorphology,and long treatment time.The Jiangsu section of the Nanjing-Hangzhou high-speed railway was taken as an example,the high-speed railway has been in operation for seven years.The status of soil erosion under natural restoration conditions along the railway was investigated to provide a guidance for comprehensive control of soil erosion along the railway.The soil erosion resistance,shear resistance,physical and chemical properties,and erosion intensity of typical sample were studied based on quarterly monitoring data from March 2018 to February 2019.Four gently disturbed plots and their adjacent undisturbed plots were selected for study.The main plant types of the plots were Robinia pseudoacacia L.,Pinus massoniana Lamb.,Zelkova serrata(Thunb.)Makino,and Ligustrum lucidum.Results show that:①The total elements and organic matter concentrations were increasing in spring and summer,and decreasing in autumn and winter.The nutrient levels of P.massoniana and R.pseudoacacia were high,while those of L.lucidum and Z.serrata(Thunb.)Makino were low,but the nutrient contents stayed well.②The trends of annual variations of scour resistance index and shear resistance index were descending in spring and summer,and rising in autumn and winter;and the scour resistance and shear resistance of P.massoniana and R.pseudoacacia stands were good.③The soil erosion intensity in summer was higher than that in summer.In spring,autumn and winter,the soil erosion intensity of P.massoniana and R.pseudoacacia stands was relatively low.④The soil moisture content,rainfall,rainfall intensity,total phosphorus content,erosion resistance coefficient,shear resistance,herbaceous vegetation coverage,and soil erosion intensity were closely inter-correlated;the rainfall intensity,water content and maximum daily rainfall,organic matter,the coverage,shear resistance,and scour resistance coefficient were major role player in the soil erosion.