本文研究了我国北方农区主要土壤对当季作物的供钾能力。结果表明，供试土壤对当季作物的供钾能力的总趋势是，取自西北的土壤较高，而取自华北和东北的土壤较低。土壤速效钾可利用部分的大小及其最低值出现的时间可以较好地反映土壤对当季作物的供钾状况。供试土壤对当季作物的供钾能力是速效钾和非交换性钾共同作用的结果。 This paper studies the supply of potassium to the seasonal crop in main soils of northern China. The results showed that the general tendency of the available soil for potassium supply of seasonal crops was higher soil from the northwest and lower soil from the north and northeast. The availability of soil available potassium part of the size and the minimum time appears to be able to better reflect the status of the soil for the seasonal crop potassium supply. The ability of the tested soil to supply potassium to the crop was the result of the combination of both available and non-exchangeable potassium.