Preparation and application properties of sustainable gelatin/chitosan soil conditioner microspheres

Traditional soil conditioners can be used as drugs to regulate elements in soil due to overuse or pollution. There are some negative effects such as low efficiency, hard to degrade and harmful to the environment when they are used. Soil conditioners prepared from sustainable macromolecules can reduce or eliminate these negative effects. In this work, gelatin (GL), chitosan (CS), magnesium ammonium phosphate (MAP) and fulvic acid (FA) were combined and prepared into GL/CS/MAP-FA soil conditioner microspheres with core-shell structure through emulsion crosslinking method. Scanning electron microscopy (SEM) and Fourier infrared spectroscopy (FT-IR) analysis results clarified the surface composition of the microspheres and revealed the good coating performance of GL/CS shell materials. The thermal stability of the microspheres was measured by thermogravimetric analysis (TGA). Water-retention, degradation and crop cultivation showed that these microspheres owned good biocompatibility, which can extend the water-retention time of the soil, settle free heavy metal ions and promote crop growth. The load of fertilizer in the microsphere can effectively prolong the release cycle and improve the utilization rate of fertilizer.