包膜控释肥料养分释放率快速测定方法的研究

包膜控释肥料养分释放率的快速测定是控释肥质量检测和制定评价标准的关键。快速测定方法可以在较短时间内,推测和评价控释肥料的养分释放速率的快慢及释放期的长短。本研究对4种不同包膜控释肥料在25℃温度条件下的静水释放过程进行了测定,并应用100℃快速浸提化学实测法的测定结果与之拟合,找出两者相同养分释放量的时间对应关系方程,并对方程进行了检验和评价;同时,还对100℃温度条件下快速浸提液进行了电导率法(简便方法)的测定。结果表明,4种不同包膜控释肥料的相同养分释放量与时间对应关系方程的拟合度均达到极显著水平;在100℃温度条件下,快速浸提测定法能在较短的时间内准确测定包膜控释肥料的养分释放率,释放期为36～个月的包膜控释肥,在104～8.h就可初步测定出养分释放期;在25℃释放期为6个月的控释肥,100℃快速浸提测定的养分释放期的最大误差为10.d(5.6%);100℃快速浸提电导率法亦可简便快速的测定出包膜控释肥的养分释放率,其对养分释放期为6个月的包膜控释肥料预测值的最大误差为15.d(8.3%)。

Fast measurement of nutrient release rate of coated controlled-release fertilizers

The fast extraction measurement of nutrient release rate of coated controlled-release fertilizer was the key for quality determination and criterion establishment.The nutrient release rate and release longevity could be estimated or evaluated in short period of time by using fast extraction measurement method.The nutrient release longevity of four kinds of coated controlled-release fertilizers was mensurated in water at 25℃,and the results matched the results of the fast extraction and chemical measurement at 100℃.The fitted equations of release time of coated controlled-release fertilizers at the same nutrient release rate were established,validated and evaluated.The fast extracted solution of coated controlled-release fertilizers at 100℃ could be mensurated by using electrical conductivity method(convenient measurement method).The results indicated that the fitted equations of release time of four kinds of coated controlled-release fertilizers at the same nutrient release rate were significantly correlated.The nutrient release rate of coated controlled-release fertilizers could be mensurated accurately in short period of time by the fast extraction measurement at 100℃.By using fast extraction measurement method at 100℃,the release longevity of 36 months of coated controlled-release fertilizers could be estimaed in 1048 hours,and the maximum forecasting error was only 10 days(5.6%) for mensurating 6 months of release longevity at 25℃.The electrical conductivity measurement method at 100℃ could also be used for mensurating the nutrient release rate of coated controlled-release fertilizers.This method was more convenient compared with the chemical measurement at 100℃,and the maximum forecasting error was only 15 days(8.3%) for mensurating the release longevity of 6 months of coated controlled-release fertilizers at 25℃.