As a result, the method of using airslake-coal to produce potassium fertilizer including humic acid was varied with different crops.

因此，在利用风化煤生产含腐植酸，应根据作物型选择工艺路线。

The results showed: inncrease application of Ca, balance application of N and K and sprinkler irrigation could increase Ca content of lettuce leaves, reduce occurring of tipburn.

结果表明，增施钙，平衡氮、及采取喷灌方式能增加生菜叶片钙含量，减少干烧心发生。