An eight-season rice-wheat rotation field experiment was conducted on two paddy soils in Siyang County and Liyang City of Jiangsu Province, respectively, to study the influence of different potash application patterns on crop yields and K-supplying power of the soils. The potash application patterns were: 216 kg K 2 O ha - 1 in the rice season and no K in the wheat season; 216 kg K 2 O ha - 1 in the wheat season and no K in the rice season; and 108 kg K 2 O ha - 1 in each season. The results show that potash application significantly increased the crop yield, and that the benefit from potash application followed the order: potash only applied in rice>splitting application in each season>potash applied only in wheat>CK. Soil tests indicated that the K-supplying power of the soils was in the reverse order after eight cropping-season harvests, suggesting that potash application priority be given to the rice season and that the application rate should be increased to get more benefit and to maintain soil K fertility.