东北坡耕地春季融雪侵蚀观测研究

为研究东北地区坡耕地的春季融雪侵蚀特征及其影响因素,选取吉林省吉兴小流域内坡耕地进行原位观测,通过分析融雪过程中径流量和含沙量的变化,以及融雪径流、土壤解冻深度等指标对融雪侵蚀的影响,探讨坡耕地融雪侵蚀过程及变化规律。结果表明,在日平均温度0~3.8℃的气象条件下,春季融雪侵蚀较为集中,径流与含沙量变化均先增加后减少。融雪径流与表层土壤解冻深度是影响融雪侵蚀的重要因素,初期融雪产流,土壤未解冻,径流急剧增加,径流量占融雪期总径流量的59.15%;中期积雪融化趋于稳定,土壤表层开始解冻,径流减少含沙量增加,侵蚀量达到最大且占融雪期总侵蚀量的41.74%;末期融雪产流停止,土壤解冻深度增加,含沙量达到最大(8.00kg/m~3)。坡耕地融雪侵蚀受垄作区域与集水洼地地形变化的影响,产流产沙具有较强规律性,二者峰值出现频次一致时,径流—泥沙呈"8"字循环滞后关系,反之呈复式循环滞后关系。

Observation on the Spring Snowmelt Erosion of Slope Farmland in Northeast China

In order to study the erosion caused by spring snowmelt of sloping farmland in Northeast China and the affecting factors,in-situ observation was carried out on a sloping farmland in a small watershed in Jixing,Jilin province.The changes of runoff and sediment yield during snowmelt were analyzed,the effects of factors such as snowmelt runoff and soil thawing depth on snowmelt erosion were investigated,and processes and change rules of snowmelt erosion of the sloping farmland were explored.The results showed that,under the meteorological conditions of the average temperature of 0 to 3.8 ℃C,spring snowmelt erosion was relatively concentrated,runoff and sediment yield increased first and then decreased.Snowmelt runoff and soil thawing depth were important factors affecting snowmelt erosion.In the early stage,runoff from melting snow increased dramatically,and accounted for 59.15％ of the total snow melting period,soil was frozen at the same time.In the middle stage,snowmelt tended to stabilize,surface soil began to thaw,runoff decreased and sediment yield continued to increase,the amount of erosion reached the maximum and accounted for 41.74％ of the total erosion.At the end,there was no snow on the slope,and the depth of soil thawing increased,runoff decreased and sediment concentration reached the maximum (8.00 kg/m3).Spring snowmelt erosion of sloping farmland was affected by the topographic changes of ridge area and catchment basin,runoff and sediment yield showed a strong regularity.When their peak frequency was consistent,runoff and sediment showed an "8" cycle lag relationship,but showed a compound cycle lag relationship when their peak frequency was inconsistent.