粒径和包膜厚度对控释肥氮素释放特性的影响

通过静水溶出率试验探讨粒径和包膜厚度对控释肥料初期溶出率、微分溶出率以及氮素累积溶出率的影响,筛选出适宜的粒径和包膜厚度的控释肥料,以此达到节省包膜材料用量、降低包膜控释肥生产成本的目的。试验结果表明,小粒径(2.5~3 mm)处理的包膜效果优于中粒径(3~4 mm)和大粒径(4~5 mm)处理的包膜效果。当包膜厚度在60~70 g/m2范围内时,中粒径处理的释放速度平缓,释放期长,控释效果优于小粒径和大粒径处理的控释效果;随着厚度的增大,初期、微分溶出率以及氮素累积溶出率都有显著减小的趋势。其中,包膜厚度对中粒径处理的影响最为显著,而对大粒径处理的影响相对较小。

Effect of Granular Diameter and Coating Thickness on Characteristics of Nitrogen Release of Controlled Release Fertilizer

This paper studied the effects of the coating thickness and granular diameter on the nitrogen release rate to select a treatment of controlled release fertilizer(CRF) which consumed less coating material but had better controlling effect to realize the purpose to reduce the cost of CRFs.The results of this experiment showed that,CRF of 2.5~3 mm diameter had the best coating effect than 3~4 mm and 4~5 mm diameters;When the coating thickness was 60 g/m2 and 70 g/m2 respectively,the release rate of CRFs of 3~4 mm diameter was mild,and its release period was longest than others diameters(2.5~3 mm,4~5 mm diameter).The capability of nutrient-controlling release of 3~4 mm diameter was better to that of 2.5~3 mm diameter and 4~5 mm diameter too;The result of effect of coating thickness on characteristics of nitrogen release was that preliminary solubility,differential solubility and nitrogen accumulated release rate all had decrease tendency remarkably with the increase of coating thickness.Among the results,effect of coating thickness on 3~4 mm diameter was best than other two diameter treatments,however on 4~5 mm diameter was smallest.