豫东北黄泛区2019年土壤侵蚀特征——以河南省兰考县为例

Soil Erosion Characteristics in Yellow River Alluvial Area in Northeast He’nan Province in 2019--Taking Lankao County as a Case

[目的]探索豫东北黄泛区2019年土壤侵蚀时空特征,为区域水土流失防治、生态环境建设和经济社会发展提供数据参考。[方法]选取兰考县为研究对象,以多源遥感影像为基础数据,通过风蚀模型、CSLE模型计算土壤风蚀和水蚀模数,以半月为时间单元,研究土壤侵蚀及其影响因子2019年内变化规律,综合分析2019年土壤侵蚀特征。[结果](1)风力因子变化呈"M"型,第3—9,21—22个半月值较高;表土湿度因子半月变化呈"波浪型",第13—18个半月值较高;降雨侵蚀力因子、林园草植被覆盖与生物措施因子B均值的变化为"先升高再降低",前者第9—16个半月值较高,后者第12—18个半月值较高。(2)风蚀模数变化呈"M型",第4—9,21—22个半月风蚀较强;全年累计风蚀模数在0~5 186.31 t/(km^(2)·a)范围内,均值为153.26 t/(km^(2)·a);仪封乡、张君墓镇风蚀模数较高,多分布在水浇地、采矿用地上。(3)水蚀模数变化呈"先升高再降低"趋势,第12—18个半月水蚀相对较强;全年累计水蚀模数在0~8 028.86 t/(km^(2)·a)范围内,均值为9.54 t/(km^(2)·a);东坝头乡、城关镇存在水蚀较强区域,主要在采矿用地上。(4)2019年兰考县共17个半月出现水土流失,占全年的70.83%;第4—9个半月水土流失面积最多;均为风蚀。全年水土流失面积为271.66 km^(2),占全县面积的24.34%;主要为轻度风蚀,占水土流失面积的96.83%。风蚀主要在仪封乡、张君墓镇、谷营镇和东坝头乡,水蚀主要在仪封乡。[结论]兰考县2019年土壤侵蚀主要发生在第4—9,21—22个半月,以轻度风蚀为主,主要分布在仪封乡、张君墓镇、谷营镇和东坝头乡。水土流失监测与防治应重点关注此时间内水浇地、采矿用地上的侵蚀。

[Objective]The temporal and spatial characteristics of soil erosion in the Yellow River alluvial area of Northeast He’nan Province in 2019 were analyzed in order to provide reference data for regional soil erosion control,ecological environment construction,and economic and social development.[Methods]The study was conducted in Lankao County.The multi-source remote sensing images were used as the basic data to calculated wind erosion and water erosion modulus using a wind erosion model and the CSLE model.Soil erosion and its influencing factors for each half-month in 2019 were studied,and the characteristics of soil erosion in 2019 were comprehensively analyzed.[Results]①The half-month U values changed over time,following an“M”shape.The values were higher during the 3rd—9th and the 21st—22nd half-month periods.The half-month value of W showed a“wave-like”change,where values were higher during the 13th—18th half-month periods.The values of R and the average values of B with respect to forest,garden,and grass first increased and then decreased with time during 2019;the former had higher values in the 9th—16th half-month periods,and the latter had higher values in the 12th—18th half-month periods.②The half-month wind erosion modulus in Lankao County showed a“wave-like”shape.Wind erosion was strong in the 4th—9th and the 21st—22nd half-month periods.The cumulative wind erosion modulus for the entire year was in the range of 0—5186.31 t/(km^(2)·yr),with an average value of 153.26 t/(km^(2)·yr).The wind erosion modulus of Yifeng Township and Zhangjun Tomb Town was relatively high,and these high values were mostly located on irrigated land and mining land.③The half-month water erosion modulus in Lankao County first increased and then decreased with time.During the 12th—18th half-month periods,water erosion was relatively strong.The annual cumulative water erosion modulus ranged from 0—8028.86 t/(km^(2)·yr),and the average value was 9.54 t/(km^(2)·yr).There were strong water erosion areas in Dongbatou Township and Chengguan Town,mainly on mining land.④Soil erosion in Lankao County in 2019 occurred in 17 half-month periods,accounting for 70.83%of the year.During the 4th—9th half-month periods,Lankao County had the largest soil erosion area,and all of the erosion in this area was wind erosion.The area of soil erosion was 271.66 km^(2) in 2019,accounting for 24.34%of the county’s area.Erosion was mainly due to mild wind erosion,accounting for 96.83%of the area of soil erosion.Wind erosion mainly occurred in Yifeng Township,Zhangjun Tomb Town,Guying Town,and Dongbatou Township.Water erosion mainly occurred in Yifeng Township.[Conclusion]Soil erosion in Lankao County in 2019 mainly occurred in the 4th—9th and 21st—22nd half-months,and was mainly in the form of mild wind erosion,mainly distributed in Yifeng Township,Zhangjun Tomb Town,Guying Town,and Dongbatou Township.Future efforts to monitor and prevent soil erosion should focus on erosion occurring on irrigated land and mining land during these time periods.