Study On Preparation And Application Of Natural Source Soil Conditioner

The soil degradation caused by human activities is becoming more and more serious,which seriously affects the sustainable production capacity of the land.Although the existing soil conditioners have slowed down the continuous decline of soil,they are also difficult to meet the needs of modern agriculture,and they also have problems such as high cost,difficult degradation,and secondary pollution.In the future,soil conditioners should develop in the direction of environmentally friendly,sustainable,and intelligent controlled release.While pursuing the high efficiency of conditioners,they should also reduce production costs.Natural-source macromolecules have high natural abundance,sustainable regeneration,good biocompatibility and biodegradability,and would not cause secondary pollution to the environment.The preparation of natural source macromolecules into microcapsules to solve soil problems has practical and theoretical research significance.（1）In this paper,natural source macromolecular GL and CS were used as carriers to support MAP and FA,and the emulsion cross-linking method was used to prepare porous drug-loaded sustained-release GL/CS/MAP-FA microspheres.Numerous micropores existed on the surface of GL/CS/MAP-FA microspheres,and the inside of GL/CS/MAP-FA microspheres was interconnected channels.These structures are conducive to the exchange of substances between the microspheres and the environment.The release cycle of GL/CS/MAP-FA microspheres in aqueous solution reached 200h.The sustained release process conformed to the parabolic diffusion model（R~2>0.95）.The control step was the outer surface/edge diffusion process.The release process was also accompanied by the dissolution of macromolecules and the dissociation of MAP.The Cu²⁺adsorption ratio of GL/CS/MAP-FA microspheres exceeded 80%,and the adsorption process was dominated by chemical adsorption.GL/CS/MAP-FA microspheres were not toxic to microorganisms and plants in the environment,and they could also promote plant growth.（2）In this paper,natural source macromolecular methylcellulose was used as a carrier to load ATP,FA,Mg SO₄ and K₂SO₄,and spray drying was used to prepare heat-sensitive methylcellulose microcapsules with a core-shell structure.A large number of holes existed on the surface and inside of the microcapsule,which was conducive to the rapid water absorption of the microcapsule.Methylcellulose microcapsules showed good heat sensitivity during water absorption process,the water absorption ratio was more than 10times of its own weight at 25℃,and the swelling ratio was 5-7 times of its own weight at35℃.The release period of FA of the methylcellulose microcapsules reached 48h,and the release process conformed to the parabolic diffusion model.The release process of the microcapsules at 25℃ was accompanied with the dissolution of methylcellulose.Methylcellulose microcapsules reduced the loss of FA nearly 50%during the leaching process,and reduced the loss of FA nearly 20%during the surface migration process.Methylcellulose microcapsules also have good biocompatibility and degradability,and can effectively promote plant growth.