This experiment accepted the split plot design. It established the main treatment potassium (K) with two levels ( K_1 150 kg/hm~2, K_2 300 kg/hm~2) ,subordinate-treatment nitrogen (N) with four levels (N_1 0 kg/hm~2,,N_2 120 kg/hm~2,N_3 240 kg/hm~2,N_4 360 kg/hm~2) and phosphorus with the same level (270 kg/hm~2). There were three replications. To study the effects of potassium, nitrogen and their interaction application on agronomic characteristics, economical characteristics, nutrient elements, kernel str...