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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Dynamic controls on wind erosion and dust generation on west-central Free State agricultural land, South Africa
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Dynamic controls on wind erosion and dust generation on west-central Free State agricultural land, South Africa

机译：南非中西部自由邦农业用地的风蚀和扬尘动态控制

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The west-central part of South Africa's Free State Province falls within the transition zone between South Africa's sub-humid, temperate grasslands to the east, and the semi-arid Karoo and arid Kalahari to the south and west, respectively. The area is characterized by low rainfall (typically 500mm or less) with high variability, but environmental conditions allow widespread dryland commercial agriculture (maize, sunflowers and stock farming). However, human activity promotes wind erosion and the area is susceptible to dust emissions. This study is the first to quantify the degree of wind erosion on the agricultural soils in the region under prevailing winter to spring climatic conditions and land management practices. Using arrays of cup anemometers, dust deposition traps and saltation impact sensors (Safires), measurements were made of the key erosivity and erodibility drivers that control the degree of wind erosion. Results demonstrate that significant quantities of dust are mobilized, particularly during the months of September and October. Thresholds of wind erosion are shown to respond particularly closely to changes in surface and aerodynamic roughness (z_0) with the amount of collected dust correlating well with measures of wind erosivity that weight the impact of higher wind speeds. Given the importance of surface roughness in controlling erosion thresholds, results show that the opportunity exists for well designed farming practices to control wind erosion. However, it is likely that climatically driven environmental change will impact on some of the identified controls on erosion (wind power, moisture availability) with the result that the wind erosion hazard is likely to increase within this marginal environment..
机译：南非自由邦省的中西部地区位于南非亚湿润，温带草原与南部和西部分别为半干旱的卡鲁和干旱的卡拉哈里之间的过渡带。该地区的特点是降雨量少（通常不超过500毫米），且变化多端，但环境条件允许广泛的旱地商业农业（玉米，向日葵和畜牧业）。但是，人类活动会加剧风蚀，并且该地区容易产生粉尘排放。这项研究是第一个量化在冬季到春季气候条件和土地管理实践下该地区农业土壤风蚀程度的方法。使用杯型风速计，灰尘沉积阱和盐分撞击传感器（Safires）阵列，对控制风蚀程度的关键侵蚀性和侵蚀性驱动器进行了测量。结果表明，特别是在9月和10月期间，有大量灰尘被运走。结果表明，风蚀阈值对表面和空气动力学粗糙度（z_0）的变化特别接近，所收集的粉尘量与风蚀率的度量密切相关，风蚀率的度量权重了较高风速的影响。考虑到表面粗糙度在控制侵蚀阈值中的重要性，结果表明，设计良好的耕作方法可以控制风蚀。但是，气候驱动的环境变化可能会影响某些已确定的侵蚀控制措施（风能，水分供应），结果是在此边缘环境中风蚀危害可能会增加。

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