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随着耕作制度的改革,轮作复种指数的提高,大量施用氮、磷肥,以及选育和推广耐肥高产品种,作物单产稳步的提高,作物从土壤中带走的钾量越来越多,在长年少施或不施含钾肥料的条件下,土壤中有效钾的水平逐年降低。据湖南省1979年14个土壤普查试点县土壤化验结果,有效钾>50ppm的占68%,比1958年土壤普查下降31%。目前,土壤的供钾水平已不能适应作物持续高产的需要。
With the reform of tillage system, the increase of crop rotation index, the large amount of application of nitrogen and phosphate fertilizers, and the selection and popularization of high-yielding and high-yielding varieties, the steady increase of crop yields and the increasing amount of potassium taken away from soil by crops Under the condition of little or no application of potassium fertilizer for many years, the level of available potassium in soil decreased year by year. According to the soil test results of the 14 counties in 1979 in Hunan Province, the effective potassium> 50ppm accounted for 68% of the total, down 31% from the 1958 soil survey. At present, the level of potassium supply in the soil can no longer meet the needs of the crop to continue high yield.