Abstract: 【Objective】To select the cementing and coating agents of slow-or controlled-release fertilizer. 【Method】 The natural kaoline and abandoned foam plastics were used to prepare nano-subnanocomposites using the methods of organic material intercalation, emulsification, and cut at high velocity. Besides, two kinds of nano-subnanocomposites were tested via several instruments including the scanning electron-microscope(SEM), the X-ray diffraction(XRD), the infrared ray spectrum(IR) and the laser granularity in this study. 【Result】(1) The organic material had been intercalated in the layers of kaoline clays, and the natural kaoline was exfoliated into nanometer sized layers. The organic material and clays formed nanocomposites through hydrogen bond combination. (2) The SEM pictures of plastic-starch nano-subnanocomposites showed that many pores and rugas ranged on the surface of film at size of 10-20 nm. 【Conclusion】 These nano-subnanocomposites can be used as the cementing and coating agents of solw- or controlled-release fertilizer.

Key words: Solw- or controlled-release fertilizer, Nano-subnanocomposites, Preparation, Testing