Abstract: ： The release characteristics of two different slow controlled release fertilizers were compared by the method of leaching in water. The results showed that there were differences in the initial nutrient release rate, the nutrient release longevity, and daily average release rates between the two different fertilizers. Type A slow-release urea had a slow dissolution rate and a long release period, its nutrient release period was 43 days, and the release rate showed an upward trend within 60 days. Type B slow-release urea had a fast dissolution rate and a short release period, which nutrient release period was 28 days. The release rate of type B slow-release urea was fast in 35 days, and the cumulative release was 84.63% in 35 days. Later release of urea was less, and the late release rate tended to be gentle.

Key words: slow controlled release fertilizer, initial nutrient release rate, nutrient release longevity, daily average release rate