When the optimal rate of potassium fertilizer is 3000kg/hm2 and the optional ratio of basic to dressing is 5:5, the potassium fertilizer should just be applied respectively in wheat.

• 冬小麦-夏玉米轮作体系中,施钾量为150kg/hm2时,两季连续分次施用钾肥经济效益最佳,施钾量为300kg/hm2时,小麦分次施用钾肥而玉米不施钾肥的经济效益最好。