东北黑土区切沟沟壁侵蚀特征及发生风险评价研究

In recent several decades of years, gully erosion in black soil region of Northeast China is aggravated year by year and it has become a serious threat to the marketable grain basis in China. Gully sidewall erosion is an important sediment yield source of gully. So the research on the gully sidewall erosion can provide the scientific suggestion for the erosion prevention and management and have the great significance to the sustainable development of black soil region of Northeast China. In this study, on the support of 3S, combined with field measurement, lab analysis, retrieval by remote sensing and GIS spatial analysis, gully sidewall erosion and other gully erosion parameters were obtained, then the development law of gully sidewall erosion was explored. Otherwise, the factors related to gully sidewall erosion such as rainfall, landform, soil, vegetation and land use were extracted and the relationship between gully sidewall erosion and environment factors were discussed. It tried to discover the key factor of controlling gully sidewall erosion and based on the above analysis, the risk evaluation on the sidewall erosion was done. By this study, it tried to improve the gully mechanism research and provide new theoretical and technical support for gully erosion. This study can also serve research on degradation process, soil and water conservation and agricultural sustainable development in black soil region of Northeast China.

近几十年来，东北黑土区的侵蚀沟问题愈演愈烈，对我国商品粮基地造成了极大威胁。沟壁侵蚀是侵蚀沟产沙的主要来源，其侵蚀规律的研究可为沟蚀防治提供科学依据，对黑土区可持续发展具有重要意义。为此，本研究在3S技术支持下，将野外测量、室内理化分析、遥感反演、GIS空间分析等研究手段将结合，获取雨季前后切沟沟壁、沟长、沟宽等一系列沟蚀形态参数，探求沟壁侵蚀发育特征规律，同时提取影响切沟沟壁侵蚀发育的降水、地形、土壤、土地利用及植被等相关因素，挖掘沟壁发育与多个因素之间的关系，探求沟壁侵蚀产生的主控因素，进而对于沟壁侵蚀的发生风险进行评价，找出沟壁侵蚀发生脆弱区。通过该研究力图完善东北黑土区沟蚀机理研究，为沟蚀研究提供相关理论和技术支持，为维护国家的粮食安全和地区生态、经济和社会的可持续发展服务。

近几十年来，东北黑土区的沟蚀问题愈发严重，对我国商品粮基带来了极大威胁。沟壁侵蚀是侵蚀沟产沙的主要来源，其侵蚀规律的研究可为沟蚀防治提供科学依据，对黑土区可持续发展具有重要意义。本研究在3S技术支持下，基于无人机和三维激光扫描仪获取典型研究区点云数据，构建侵蚀沟三维模型，将野外测量、遥感反演、GIS空间分析等研究手段结合，从三维模型中提取切沟沟壁、沟长、沟宽等一系列沟蚀形态参数，探求沟壁侵蚀发育特征规律；同时提取影响切沟沟壁侵蚀发育的相关因素，挖掘沟壁发育与多个因素之间的关系，探求沟壁侵蚀产生的主控因素，进而构建Logistic模型对沟壁侵蚀的发生风险进行预测和评价，找出沟壁侵蚀发生脆弱区。结果表明黑土区切沟侵蚀总体特点为沟长沟深，侵蚀体积主要受其长度影响；东北黑土区切沟发育过程是沟头溯源侵蚀、沟壁坍塌和沟底下切等过程相互作用的结果，切沟沟长和侵蚀体积均未与汇水面积和坡长呈现出好的拟合关系；研究区切沟产生的主导过程是坡面漫流，黑土区切沟侵蚀发生的临界值较世界其他地区要大；坡度、坡长、坡向、坡型和剖面曲率是沟壁侵蚀主控影响因素，作为构建模型的因子使用；所构建Logistic模型通过Hosmer-Lemeshow拟合优度和χ2检验，模型总体预测精度为73.1%，非沟蚀区预测精度为65.2%，沟蚀区预测精度为79.7%，证明模型可以使用；最终评价得出研究区沟壁侵蚀微度发生风险区面积所占比例为9.96%，轻度发生风险区面积所占比例为32.36%，中度以上发生风险的区域面积所占比例为7.68%。东北黑土区的沟壁侵蚀发生风险是极其高的，基于预测结果进行沟蚀预防和治理非常重要。通过该研究力图完善东北黑土区沟蚀机理研究，为沟蚀研究提供相关理论和技术支持，为维护国家的粮食安全和地区生态、经济和社会的可持续发展服务。