Nutrient release characteristics of controlled-release urea in water and different soils

Nutrient release characteristics of controlled-release urea (CRU) in water and soils was studied, and the differences of nutrient release characteristics of CRU in water and soils were compared and the effects of soil types on nutrient release characteristics of CRU in different soils were also studied. The results show that the preliminary soluble rate of CRU is 1.7%, the cumulative release rate in the 28 days is 59.2%, and the release period is about 50 days under 250.5℃. The nutrient release rate of CRU in the paddy soil at the first 50 days is significantly lower than those of the fluvo-aquic soil and yellowbrown soil. The releasing rate of N in the paddy soil from 50 d to 140 d is the highest. After 140 days, there is no relationship between the nutrient release rate and the soil type. The nutrient release rates of CRU in different types of soil are significantly associated with those in water.