黏土基氮·磷·钾缓释肥的制备及其释放特征

Preparation of Clay based Slow-release Fertilizers Containing Nitrogen,Phosphorus and Potassium and its Release Characteristics

[目的]利用黏土作为载体制备黏土基氮、磷、钾缓释肥,是提高化肥利用率的有效途径。[方法]以膨润土和高岭土为载体,采用研磨法制备了多种黏土基氮、磷、钾肥及复合肥,并用淋溶试验评价了肥料的释放性能,得到了氮、磷、钾的释放特征曲线。[结果]相比于传统化学肥料,使用高岭土和膨润土复合的氮、磷、钾肥对氮、磷、钾元素都起到了较好的缓释效果。膨润土对氮、磷、钾的缓释性能要优于高岭土,其原因在于膨润土单元层内电荷不平衡及边缘大量断键的存在,并且其水合膨胀后具有较大的层空间,能够将氮、磷、钾锁定在膨润土层间,不会轻易流失。制得的膨润土基复合肥CLAY-N-P-K中氮、磷、钾都具有较好的缓释性能,就释放速率而言,氮的释放速率最快,钾次之,磷最慢。[结论]研究膨润土基氮、磷、钾肥的缓释特征对缓释肥的生产和使用有重要价值。

[ Objective] It was an effective way to improve the utilization efficiency of release fertilizer using clay as a carrier for preparation of nitrogen,phosphorus,and potassium fertilizer. [ Method] A variety of clay-based nitrogen,phosphorus,potassium fertilizer and their complex fer- tilizers were prepared by grinding methods using bentonite and kaolin as supporters. Release characteristic curves of nitrogen,phosphorus and po- tassium were obtained by the leaching experiments. [ Result] Compared with the traditional fertilizers,the release performances of nitrogen,phos- phorus and potassium using bentonite and kaolin as supporters were better. Moreover,bentonite was superior to kaolin. The reason was that the charge disbalance within layer sheets of bentonite, and there was a large number of broken bonds in the edge of bentonite,then a large expansion space after hydration, which made nitrogen, phosphorus and potassium were locked in the interlayer of bentonite, and wouldn＇t lose easily. Nitro- gen,phosphorus and potassium of bentonite based complex fertilizer CLAY-NPK had a good slow-release property. The release rate of nitrogen was the fastest ,followed by potassium ,and phosphorus was the slowest. [ Conclusion] Research on the slow-releasing characteristics of nitrogen, nhnsnhnms~ and nntAgalum fartillzar hAaerl hantnnit~ hs^rl , o＇r^t vAlup far th,~ nrtw]ll^tinn rtnr] the 1,aaa~ nf ~1~ f~.-t;I;~o~