Humic acid is a kind of organic matter with high molecular quantity and satisfactory biological activity,and there are abundant humic acid in airslake-coal.According to the peculiarity that sweetpotato and ginger belong to the crop favoring potassium,two kinds of potassium fertilizer including humic acid were prepared and applied in the field experiment of sweetpotato and ginger.The experimental results showed that to compare with the application of K2SO4,applying the potassium fertilizer including common humic acid(HA-K)in the sweetpotato had no effect on storage roots per plant,significantly increased the fresh weight per lump,and increased storage root yield by 8.12%;applying the potassium fertilizer including active humic acid(AHA-K)in the sweetpotato had no effect on the fresh weight per lump,significantly increased storage roots per plant,and increased storage root yield by 9.52%.Applying HA-K and AHA-K in ginger increased root yield by 5.28% and 12.05% separately,and the degree of increase of root yield was higher in the AHA-K management as compared with in the HA-K management.As a result,the method of using airslake-coal to produce potassium fertilizer including humic acid was varied with different crops.