通过田间长期定位施肥、室内模拟及大量室内分析对黄泛区砂质潮土进行了研究。结果表明：砂质潮土速效钾含量中等偏低，级效钾含量高，二者平均分别为７６．４ｍｇ·ｋｇ￣（－１）和６３１．７ｍｇ·ｋｇ￣（－１）．各形态钾含量为水溶态钾＜代换态钾＜非代换态钾＜矿物态钾，代换态钾与非代换态钾分别占全钾的０．３２％和３．５％，代换态钾和非代换钾与土壤物理性粘粒显著正相关，水溶性钾与之成相关，土壤粘土矿物以云母为主，土壤缓效钾易于释放。是作物钾的主要供应者。不同施肥措施影响土壤钾素的平衡，单施有机肥或氮磷钾化肥基本可维持土壤原有速效钾水平。不施肥、施氮磷化肥或氮磷配施有机肥均不能满足土壤钾素平衡，十年间速效钾降低１７．９－３７．９ｍｇ·ｋｇ￣（－１），达１８．６－３７．５％。连续种植小麦－玉米而不施钾ＡＲ￣Ｋ。逐年下降，直到０．００１１水平。钾肥施用在小麦、玉米、棉花、花生、西瓜等作物上有显著效果，而且增产幅度逐年增加，因此，应对土壤钾素状况注意监测，在生产上适时、适量地补充钾肥。 The sandy soils in the floodplain were studied through long-term fertilization, indoor simulation and a large number of indoor analyzes. The results showed that the content of available potassium in sandy soil was medium low and the content of potassium was high. The average contents of available potassium were 76.4 mg · kg ~ (-1) and 631.7 mg · kg ~ (-1), respectively. The potassium content in each form is water soluble potassium