缓控释肥料养分释放特性评价及快速测定方法研究

EVALUATION OF NUTRIENT RELEASE CHARACTERISTICS OF SLOW AND CONTROLLED-RELEASE FERTILIZERS AND FAST MEASUREMENT METHOD

采用水中浸提释放法和土壤恒温培养法,按照缓控释肥料行业标准(HG/T3931-2007)和欧洲标准化委员会(CEN)推荐的控释肥料评价标准,对5种缓控释肥料的氮素释放特性进行了评价。结果表明:采用25℃常温浸提法测定与100℃快速浸提法测定,后者的养分释放率加快。用100℃快速浸提法建立预测预报缓控释肥料在常温下(25℃)的释放期的回归方程(一元二次方程,相关系数大于0.98),预测值与实测值相差1～3 d。对于25℃常温浸提法测定释放期分别为66 d和84 d的塑料包膜控释复合肥(CRF)和树脂包膜控释复合肥(CRF3),用100℃电导率法预测的养分释放期分别为65 d和81 d,相对误差小于3.5%,可见电导率法也可以准确快速地预测包膜控释复合肥料的养分释放率和释放期。用初期养分释放率、平均释放率和养分释放期等参数,可用于缓控释肥料的综合评价。

Nutrient release rate is the key to quality determination and evaluation of slow/controlled-release fertilizers. Nutrient release characteristics of five slow/controlled-release fertilizers were evaluated according to the industry standard of slow/controlled-release fertilizer （HG/T 3931-2007） and the standard recommended by the Committee of European Normalization （CEN） using water extraction method and soil incubation method. Nutrition release was accelerated when temperature of the solution in the water extraction method was raised from 25℃ to 100℃. The regression equation for prediction and forecast of the 100℃ fast extraction method fit a quadric equation in one variable with a correlative coefficient being 〉 0.98, and could be used to quickly and precisely predict release duration of slow/controlled fertilizers. The difference between the measured value and predicted one was only one to three days. Besides, electric conductivity measurement could also be used to quickly and precisely predict nutrient release rate and duration. By using the electric conductivity measurement at 100℃, the release duration of CRF2 and CRF3 was predicted to be 65days and 81days, less than 3.5% in difference from their measured duration of 66 days and 84. Parameters, like initial nutrient release rate, mean release rate, and release duration, could be used for integrative evaluation of slow/ controlled-release fertilizers.