风水复合侵蚀区"灌-草"斑块格局对侵蚀产沙动力过程的作用机理研究

Shrub encroachment results serious degradation and soil erosion of grassland in arid and semi-arid regions. In this study, the differences of sediment yield in different development stages of the transition from grassland to shrub land will be studied. Vegetation investigation and simulated rainfall experiment will be conducted on the grassland in the Erdos, Inner Mongolia, combined with digital reconstruction technology of microrelief. The coupling effects of different patterns of "shrub-grass" patches and micro topography on the runoff and sediment yield will be discussed systematically. The transformation process of erosion energy in the transition from grassland to shrubland will be analyzed. The acting mechanism of shrub patch on the erosion and sediment yield will be revealed. The response relationship of grass-shrub vegetation pattern with the coupling of micro topography evolution and sediment yield will be established based on the energy conversion process to provide scientific evidence for ecological restoration and soil and water conservation in arid and semi-arid regions.

干旱半干旱地区的草地灌丛化不仅导致草地退化而且坡面土壤侵蚀问题严重。本研究针对草地灌丛化过程中灌丛斑块不同发展阶段侵蚀产沙差异明显的问题，选择内蒙古鄂尔多斯草原区草地灌丛化坡面为研究对象，通过植被调查和模拟降雨试验，结合微地貌数字重建技术，系统研究不同“灌-草”斑块格局和灌丛下微地貌耦合作用对坡面产汇流和产沙过程的影响，重点分析灌丛化过程中侵蚀能量的转化过程，从动力学角度揭示灌丛化过程中灌草斑块对侵蚀产沙的作用机理，基于能量过程建立草地向灌木转换过程中植被格局、微地貌演变与侵蚀产沙的响应关系，为干旱半干旱区草地生态修复和水土保持生态建设提供科学依据。

鄂尔多斯高原退化草地存在侵蚀产沙显著差异的问题。本项目针对草地灌丛化过程中灌丛斑块植被格局转换引起的侵蚀动力变化问题，通过径流冲刷和模拟降雨试验研究了灌丛化过程中“灌-草”斑块格局对坡面径流和泥沙过程的影响。分析了不同灌草格局下径流和泥沙颗粒变化特征，采用水流剪切力、水流功率和单位水流功率等水动力学指标描述不同灌-草格局之间的变化规律，建立了水流剪切力、水流功率、泥沙颗粒和信息维数组成的土壤剥蚀率预测模型，阐明了坡面“灌-草”灌丛化过程中植被斑块格局与侵蚀产沙响应关系，为生态脆弱区草地植被恢复和水土流失治理提供科学依据。