【摘要】 我国北方传统耕作模式的犁耕、耙磨及磨平整地措施对农田近地表风沙活动影响显著。通过对春季半干旱沙区农田风沙活动的观测,本文对犁耕、耙磨磨平两种处理下近地表0~60 cm内输沙率和风沙流结构随田块长度的变化规律进行了研究。结果表明,耙磨磨平处理破坏了犁耕在农田地表形成的非可蚀性土块结构,使近地表0~60 cm内输沙率增大,在强沙尘事件中增加幅度可达数10倍。犁耕地表上输沙率随田块长度的增加呈指数关系递增,而耙磨磨平后风沙流发育的饱和路径长度减小,在强沙尘事件中近地表输沙率随田块长度的增加而递减。此外,上风向处犁耕地表低层输沙比例(Q0-10/Q0-60)小于耙磨磨平地表,且随田块长度的增加逐渐增大,而耙磨磨平后风沙流结构随田块长度的变化不大。更多还原

【Abstract】 Through field observation of blown-sand movement at semi-arid sandy region in spring,it studied the change of sand transport rate and blown-sand structure at the height of 0～60 cm with increasing field length on field surface after moldboard plowing,harrowing and milling respectively.The results indicated that the practice of harrowing and milling destroyed non-erodible clods formed by previous moldboard plowing practice,which increased sand transport rate in 0～60 cm,and the increment may reach several tenfold.On field surface after moldboard plowing,sand transport rate increased by an exponential function with increasing field length,while after the practices of harrowing and milling it decreased with increasing field length during strong dust storm.Compared with moldboard plowing,the practice of harrowing and milling decreased the critical field length for saturation of blown-sand,and increased the proportion of sand transported in 0～10 cm(Q0-10/Q0-60) at the boundary of windward.Moreover,Q0-10/Q0-60increased with increasing field length on field surface after moldboard plowing,while it changed little on field surface after harrowing and milling.更多还原