宁杭高铁运营期典型样地侵蚀因子特征研究

The Characteristics of Erosion Factors of Typical Sample Plots during the Operation Period of Nanjing-Hangzhou High-Speed Railway

为研究高铁沿线侵蚀因子变化,制定运营期土壤养护措施,在宁杭高速铁路(江苏段)沿线选取典型样地,于2018年3月至2019年2月对样地土壤理化性质、降雨特征等进行定点监测,测定降雨量及土壤理化指标、抗冲性、抗剪性、侵蚀模数,并结合典型区段2014-2018年遥感影像进行植被、土地利用现状等信息提取,从而计算和预测土壤流失量。研究表明:扰动后土壤养分含量普遍低于原状土;扰动地貌自然恢复速度比原状地貌慢,随自然恢复时间延长土壤理化指标水平差别呈增大趋势;土壤含水率、降雨量、降雨强度与侵蚀模数呈显著或极显著正相关,全磷含量、抗冲刷系数、抗剪性与土壤侵蚀强度呈显著或极显著负相关;扰动后可以草本为先锋植被,快速覆盖地表,控制水土流失,当草本覆盖率达到76.5%以上时,土壤侵蚀强度会降至微度水平;土壤侵蚀模数整体呈现逐年降低的趋势,但在回坞左侧典型样地仍需要进行治理。

In order to study on the variation of erosion factors in areas along the line of high-speed railway and prepare the soil conservation measures in the operation period,the paper selected typical sample plots along the line of Nanjing-Hangzhou high-speed railway( Jiangsu section),conducted fixed-point monitoring on soil physical and chemical properties and rainfall characteristics from March 2018 to February2019,determined rainfall,the index of soil physical and chemical properties,impact resistance,shear resistance and erosion modulus and calculated and predicted the amount of soil loss combined with the extracted information of vegetation and current situation of land use of remote sensing images in the period of 2014-2018. The outcomes show that a) the content of soil nutrient after disturbance is generally lower than that of undisturbed soil;b) the natural recovery speed of disturbed landform is lower than that of undisturbed landform and the difference of nutrient level increases with the increase of natural recovery time;c) the soil moisture content,rainfall and rainfall intensity show significant or extremely significant positive correlation with erosion modulus and the total phosphorus content,scouring resistance and shearing resistance show significant or extremely significant negative correlation with soil erosion intensity;d) after disturbance,it is necessary to take herbs as the pioneer vegetation to cover the surface quickly and control soil erosion. When the coverage of herbs reaches to 76.5% or more,the soil erosion intensity will reduce to the micro level and;e) the erosion modulus shows a trend of decreasing year by year,while the typical plots on the left side of Huiwu still needs to be controlled artificially.