top soil layer

基本解释

Under the action of wind, forced convection of air above ground and water evaporation of top soil layer will be greatly enhanced.
在风的作用下，地表上部空气的强制对流和表土层中的水分蒸发大大增强，对冻土层的热状况产生重要的影响。
TP, rapid available phosphorus, organic content and rapid available iron gradually decreased in the top soil layer of wetland along the flow path.
总体而言，来水中的磷、有机质和速效铁以沿程逐渐降低的方式分布于湿地表层土壤中。
TP, rapid available phosphorus, organic content and rapid available iron were gradually decreased in the top soil layer of wetland along the flow path.
总体而言，来水中的磷、有机质和速效铁以沿程逐渐降低的方式分布于湿地表层土壤中。

C. and A.D. 500 by brushing away the dark top layer of barren desert to reveal the light, sandy soil underneath, wrote Clive Ruggles, an archaeologist from the University of Leicester in the United Kingdom, in an email.
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地表土层
Protection of grassland vegetation and top soil layer is vital to avoiding the development of blowouts.
保护沙质草原区植被和地表土层不受破坏是防止风蚀坑发生发展的关键。