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部分冻结的土壤能加重地表径流的流失并降低土地的生产力。美国明尼苏达州在 1986～ 1990年及 1987～1988年解冻时节分别对普通黑土、钙质黑土进行了水土流失评估。在秋季耕作前分别采取有覆盖、无覆盖处理 ,翌年解冻时节 ,分 4个时期分别对经前 1a秋季用铧式犁、凿形犁耕作过的地块进行 6 4mm/h的人工降雨。在降到 96mm的雨后 ,普通黑土、钙质黑土的水土流失差别不大。方差分析表明 ,降雨日期和覆盖处理都影响径流 ,但仅仅覆盖处理影响两类土的土壤流失。回归分析表明表层土愈湿愈平整 ,冻土层离地表愈近 ,则径流量愈大。在春季雨量为 96mm的条件下 ,径流、随机糙度、土壤含水量和残余物覆盖度决定了土壤流失近 6 0 %的变异性。在同一天内连续降雨将使黑土的水土流失速率提高至少 5 0 % ,黑钙土的水土流失速率提高 10 0 %。在寒冷地区 ,秋季的耕作能促进土壤增温并有利于春季的播种和土壤质地变粗。土壤的快速解冻和作物残余物的覆盖是解冻时节减少水土流失的理想方法。
Partially frozen soils can exacerbate surface runoff losses and reduce land productivity. In Minnesota, USA, soil erosion was evaluated on ordinary black soil and calcareous black soil during thawing time from 1986 to 1990 and from 1987 to 1988 respectively. Before the autumn tillage, they were covered and covered with no cover, thawed in the following year, and artificial rainfall of 64 mm / h was made to the plots that had been plowed by plowshare and chisel plow in the first autumn of each year in four periods. After the rain dropped to 96mm, ordinary black soil, calcareous black soil little difference between soil and water loss. Analysis of variance showed that both rainfall dates and cover treatments affected runoff, but only cover treatments affected soil loss for both types of soils. Regression analysis showed that the wetter and smoother surface soil, the nearer the surface of the frozen soil, the larger the runoff. Under spring rainfall of 96 mm, runoff, random roughness, soil moisture content and residue coverage determine the variability of nearly 60% soil loss. Continuous rainfall on the same day will increase the rate of soil erosion in black soil by at least 50% and increase the rate of soil erosion in black soil by 100%. In cold regions, autumn farming can promote soil warming and facilitate planting in spring and thicker soil texture. Rapid soil thawing and crop residue coverage are the ideal ways to reduce soil erosion during the thawing season.