控释尿素在水及不同类型土壤中的养分释放特征

试验采用静水培养和土壤培养研究控释尿素的养分释放特征，比较其在不同类型土壤和静水中的养分释放差异， 探讨土壤类型对其养分释放的影响。结果表明，试验选用的控释尿素在250.5℃静水条件下， 初期养分溶出率为1.7%， 28 d养分累积释放率为59.2%， 释放期为50 d， 控释尿素在土壤培养的前50 d， 水稻土中的氮素表观释放率显著低于潮土和黄棕壤中， 50~140 d在水稻土中的氮素表观释放率最高，140 d之后在三种类型土壤中的氮素表观释放率无显著差异。控释尿素在不同类型土壤中的养分表观释放率均与在静水中的显著相关。

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 25±0.5℃. 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.