Preparation And Application Effect Of Biochar Inoculated Pseudomonas Putida Rs-198

In recent years,due to the large evaporation of water and unreasonable use of chemical fertilizers in Xinjiang,the soil salinization is becoming more and more serious.The strain Pseudomonas putida Rs-198(Rs-198),was screened by our research group in the early stage,has good salt tolerance and growth promotion performance.However,the complex soil environment causes the low stability and poor effectiveness of the free Rs-198.Since biochar is a kind of functional material with rich nutrient elements,developed pores,large specific surface area and low cost,it can be used as the carrier of Rs-198.In this paper,biochar inoculated Pseudomonas putida Rs-198(BIRs198)was prepared by mixing biochar and Rs-198 in a certain proportion,and the effects of physical and chemical properties of biochar and on Rs-198 loading were studied.The salt-tolerance and growth promoting effect of BIRs198 was investigated through the application experiments of pepper pot and grape in the field,and the effects on soil physicochemical properties and bacterial diversity were investigated.The main research results are as follows:(1)The effect of different carrier properties on bacterial agent loading.The elemental analysis of bamboo charcoal(BB),apricot shell charcoal(ACAS)and walnut shell charcoal(ASWS)showed that the carbon content of ACAS,ACWS and BB increased successively,while the polarity and aromaticity decreased successively.The roughness increases in turn.Surface area: ACWS>ACAS>BB.The point of zero charge of the three materials is very similar.EDS analysis showed that the carbon materials contained potassium,calcium,magnesium,silicon and other nutrients,and SEM confirmed that Rs-198 was loaded on the surface of biochar.FTIR indicated that there was no chemical change between the three carbon materials and Rs-198.Immobilized cells count order for ACWS>BB>ACAS.The three types of carbon are close in size and have little relation with the load.The contact angle has an effect on the number of loaded cells.Zeta analysis showed that ACAS was the most stable after loaded Rs-198,the bacteria number of ACWS loading was the most because the lower potential difference was more conducive to loading.Correlation analysis shows that pH,EC,contact angle and Zeta of biochar had an impact on the Rs-198 load.This study provides a research idea for PGPR to select an appropriate carrier and understand th e interaction between PGPR and carrier.(2)The salt-tolerant and growth-promoting effect and mechanism of biochar,Rs-198 and BIRs198 on pepper.The results of pot experiment show that under 0.5%NaCl salt stress,compared with blank,the plant height,root length,fresh weight and dry weight of pepper treated with BIRs198 increased by 26.43%,24.27%,42.59% and 50.00%,respectively.Stem diameter,leaf area,leaf number and RWC increased by 23.41%,14.03%,12.79% and 3.54%,respectively.Chlorophyll a and b increased by 47.22% and 62.5 0%,respectively.The soluble protein,soluble sugar,proline and electrolyte leakage decreased by 33.07%,57.78%,62.20% and 36.88%,respectively.The SOD,PPO and POD decreased by 35.68%,31.85% and 37.20%,respectively.The results showed that BIRs198 alleviated salt stress and promoted pepper growth by reducing the accumulation of osmotic substances and antioxidant enzymes.(3)The effect of carbon-based agents on plant,soil and microorganism.Application of carbon-based agents in grape field was carried out.The results show that the length diameter,width diameter and weight of grapes treated with BIRs198 increased by 3.8%,3.8% and 7.6%,respectively,compared with the control treatment(P<0.05).The soluble protein,hardness of grape treated with BIRs198 was increased by 28.6% and 10.8%,while the total acid content decreased by 15.8%.The EC,AN,AP,AK,OM,urease activity,sucrase activity increased by 87.3%,24.28%,73.2%,78.17%,71.6%,17.50% and 82.11%,respectively.16 S rRNA showed that the application of BIRs198 resulted in an increase in the number of Gemmatimonadetes,Actinobacteria,Bacteroidetes,and Planctomycetes in the soil(P<0.05),while a decrease in the number of Acidobacteria,Chloroflexi,Rokubacteria,and Nitrospirae in the soil(P<0.05).RDA analysis showed that the BIRs198 amendment had significant effect on soil microbial community structure,and key environmental factors included AN,AP,AK,urease activity and sucrase activity.This provides a basis for the sustainable application of carbon-based agents in agriculture.