Research progress on nano-materials application in slow/controlled-release fertilizers

Slow/controlled-release fertilizers refer to those fertilizers which are modified by physical, chemical, or physico-chemical methods to slow or control nutrients release. Slow/controlled-release fertilizers have been proved of better meeting the nutrient requirements of plants, improving the utilization efficiencies of nutrients, and reducing environmental risks, so their application is an important way to the attainment of agricultural green development. Nano-materials have the characteristics of small size, large surface area and significant interfacial effect, so as to be used for slow/controlled-release fertilizers. We separately overviewed the research and application of slow/controlled-release fertilizers containing nano-oxide, nano-cellulose, nano-carbon and nano-clay, etc. Physical blending, chemical grafting and impregnation-adsorption are the main methods for producing slow/controlled-release fertilizers containing nano-materials. The important functions of nano-materials are hydrophobicity, adsorption, water retention, environmental responsiveness, and self-repair in slow/controlled-release fertilizer. Abundant functional groups, physical cross-linking points and micro/nano bulges of nano-materials are the key factors to improve the slow/controlled-release effect. Developing low-cost natural organic nano-materials, exploring simple and efficient modification methods, and clarifying performance regulation mechanism of nano-materials are still needed in the future.