Study On Preparation Of Soil Conditioner From Natural Polymer Materials And Application In Planting Experiment

Microcapsulated soil conditioner was a kind of microspheres with sustained-release effect and can be prepared to improve the utilization efficiency of fertilizer and reduce the use amount of fertilizer.It mainly consists of the core material which was conducive to the growth of crops and the shell material which covers the capsule core.Compared with the traditional fertilization method,microcapsulated soil conditioner could control the release of fertilizer,prolong the residence time of fertilizer in the soil,improve the chemical and physical properties of soil,and then improve the total nitrogen and carbon content of soil.Microcapsulation technology was mainly used in food,medicine and textile products such as direction.Different from the above application,used for agriculture in the direction of microcapsulated material not only requires the harmless and the solubility of capsule core material,the slow release time,performance degradation in the environment as well as the particle size and so on all have different requirements.So in the direction of the agricultural research prospect of application is greater.In this paper,the natural material sodium alginate was selected as the capsule-shell material.Urea and fulvic acid,the water-soluble fertilizer,were used as the capsule-core material.And the microcapsulated soil conditioner was prepared by the method of orifice and coagulation bath.The research was mainly carried out from the following two aspects:?1?The microencapsulated soil conditioner was prepared by the rapid cross-linking reaction of sodium alginate and calcium chloride to form microencapsulated capsules,and the urea and fulvic acid solutions were coated.Polarizing microscope?POM?,infrared spectroscopy?FTIR?,thermogravimetry?TG?and other characterization methods were used to test the structure and physical and chemical properties of microcapsulated soil conditioner.The sustained-release properties,degradation properties,ion-exchange properties and water and fertilizer retention properties of microcapsulated soil conditioner were characterized.The results showed that nutrient components were not modified after coated with microcapsulated material,that is,the growth promoting effect of fertilizer on crops was not affected.Moreover,the microcapsule material was almost completely degraded at 350?,which would not cause secondary pollution to the environment.Moreover,SA8P25 has the best sustained-release effect,retaining 50%fulvic acid content at 450h and completely releasing the coated fulvic acid amount at 1000h.Moreover,after degradation for 21d,the mass loss was about 75%,which confirmed the results of TGA that the materials almost did not cause secondary pollution to the environment.After SA8P25 treatment,the content of calcium ions in the soil was 0.97mg/L,much higher than the control group?0.16 mg/L?,and the water retention time was 2815 min,much longer than that in the blank control group?595 min?.?2?On the basis of the above experiments,the experiment of planting Shanghai cabbage was carried out by using the sharp-coagulated bath equipment for mass production of microcapsulated soil conditioner,and Shanghai Sunqiao Agricultural greenhouse was selected as the site of Shanghai cyan planting experiment.Parameters such as NBI content,photosynthesis intensity,root length and leaves area of"Shanghai cabbage"were measured.Crop growth curve,crop yield,soil total nitrogen and carbon content were recorded and analyzed.The results showed that the NBI content of Shanghai cabbage with microcapsulated soil conditioner remained high after 10 days?about 27?,while the traditional fertilizer group and the blank control group showed a significant decrease?about 18?,indicating that the content of chlorophyll in Shanghai cabbage with microcapsulated soil conditioner remained high after 10 days?about18?.The photosynthetic intensity of W4H5 was 19.9?mol·m^-2·s^-1 in the experimental group and5.9?mol·m^-2·s^-1 in the blank control group,indicating that it had higher photosynthetic intensity and was conducive to the growth of crops.Moreover,the root length of W4H5 was 130.5cm,much longer than that of the blank control group?55.6cm?.The yield of W4H5 in Shanghai was6.90g?dry weight?and that of the blank control group was 4.01g?dry weight?,indicating that microcapsulated soil conditioner could effectively improve crop yield and promote production.