包膜肥料控制释放速率的测定

Determination of Controlled-release Rate for Coated Fertilizer

分别用水浸泡法和土壤溶出率法测定了3种包膜肥料氮素的释放速率,研究了这两种测试方法的特点以及应用范围。结果表明:同一肥料在水中以及土壤中氮素的释放速率和释放模式有所不同;水浸泡法适用于水田用或者释放速率小的包膜肥料释放速率的测定,而土壤溶出率法适用于旱地上用或者释放速率大的包膜肥料释放速率的测定;水浸泡法可以快速比较不同包膜肥料的缓/控释性能,但与肥料在土壤中的实际释放期有偏差;土壤溶出率法能较好地模拟施肥的情况,但测试时间长。

The nitrogen-release rates of three coated fertilizers were determined by the “immersed in water” and “immersed in soil” method respectively. The characteristics of the two methods and their applicable fertilizers were studied. The results indicate that： 1） There is significant difference of release patterns between the fertilizer “immersed in water” and the fertilizer “immersed in soil”; 2） The “immersed in water” method is suitable for slow release or coated fertilizers applied in paddy field, while the “immersed in soil” method is suitable for comparatively quick release or fertilizers applied in dry soil; 3） Considerable errors might exist when the “immersed in water” method is applied to estimating the field＇s fertilizer effect, though the method can make quick comparison of slow/controlled release properties among different coated fertilizers; on the contrary, the “immersed in soil” method could better simulate the releasing characteristics of coated fertilizers in soil, but the determination time is longer.