吸附性矿物膨润土对肥料的控释作用初探

利用吸附性矿物膨润土来制备控释肥料是当前农业生产和环境保护领域的重要课题．采用钠基膨润土作为包裹剂，以正硅酸乙酯（TEOS）黏结保护层，将氮、磷、钾肥在不同分散剂中进行包裹处理，通过滴淋实验测试了控（缓）释性能及作用特征．结果显示，钠基膨润土对氮、钾肥等易溶肥有良好的缓释效果，且土样的含量越高效果越明显；而对磷肥等难溶肥有促释效果．红外光谱分析结果，初步表明包裹过程是对肥料的物理性质上的调整与改善，并未破坏肥料的有效成分。

Preliminary study on features of controlled release of bentonite-coated compound fertilizers

Using natural Na-bentonite minerals and conventional fertilizers to produce the controlled-release compound fertilizer is of great significance in the field of agriculture and environment preservation.Here Nabentonite was used as wrapping reagent,and tetraethyl orthosilicate(TEOS) as adhesive to link layers of bentonite,and thus the compound fertilizers of bentonite-coated nitrogenous,phosphate and potassium fertilizers were prepared in different dispersants.The controlled release property was tested and analyzed by means of drop-leaching experiment.The results show that the Na-bentonite exhibits slowly releasing effect for the soluble N and K fertilizers,and the effect can be improved by the increase of the bentonite content.However,the Na-bentonite promotes the release of insoluble P fertilizer.The infrared spectra(IR) measurements reveal that the coating of Na-bentonite on fertilizers is a physical process without destroying the chemical structure of the fertilizers.