Study On The Improvement Effect Of Soil Amendment Based On Biochar On Sandy Soil

Biochar is considered to be a high-quality soil amendment due to its porous,alkaline,high stability and huge specific surface area.Applying biochar to soil can not only improve the physical and chemical properties of soil,but also affect the microbial community structure of soil,thereby promoting plant growth.In this study,the sandy soil of Dalad Banner in Ordos was used as the improvement object,and the biochar was prepared from the crop straw planted by Yitai Beimu Pastoral Company,and the field plot experiment of’straw carbonization-soil improvement’technology was carried out.In April 2021,the soil of Zhaojun Town,Dalad Banner,Ordos City,was applied,and the application amount was set at five levels:control group Z0(0 kg biochar/hm~2),Z1(10 kg biochar/hm~2),Z2(30 kg biochar/hm~2),Z3(50 kg biochar/hm~2),Z4(70 kg biochar/hm~2).Sorghum was planted from April 20,2021,and no other influencing factors were added during sorghum growth except for normal field management.The soil and crop samples were collected in October 2021,and the physical and chemical properties of the soil and the growth and development of the plants were measured after the application of biochar.The effects of different amounts of biochar on the absolute abundance and community structure(relative abundance)of bacteria,nitrogen-fixing bacteria and fungal communities in sandy soil were analyzed by real-time fluorescence quantitative PCR and Illumina Miseq sequencing.The relationship between biochar and soil physical and chemical factors and microbial community structure was analyzed.The main results are as follows:(1)The sandy soil in this study was neutral,and the soil p H value increased slightly after the application of biochar,but the effect was not obvious.Biochar can significantly increase soil water content,and gradually increase with the increase of biochar content.(2)The application of biochar can greatly improve the content of organic matter in soil,and the greater the amount of biochar applied,the higher the content of organic matter.Low application of biochar can increase the content of available phosphorus in soil.(3)The application of biochar promoted the growth of roots and stems of sorghum,and also had a significant effect on the fruit yield of sorghum crops,mainly reflected in the size and quality of sorghum grains.After the application of biochar,the content of water and tannin in sorghum fruit decreased,and the content of crude protein,crude fat and crude ash increased significantly after the application of biochar.The changes after biochar treatment were not significant.The total starch content in sorghum was not affected by biochar,and the amylopectin content decreased.(4)The application of biochar had a significant effect on the absolute abundance of bacteria in the soil.The overall performance was that with the application of biochar,the species richness and community diversity of bacteria in the soil increased,but it was not proportional to the amount of biochar.In this study,the changes of bacterial community structure were more closely related to soil available phosphorus than soil organic matter,available nitrogen and p H.(5)The application of biochar has no significant effect on the absolute abundance of nitrogen-fixing bacteria in soil.Only the application of a large amount of biochar can promote the reproduction of nitrogen-fixing bacteria.The diversity index analysis showed that the diversity and richness of nitrogen-fixing bacteria in the soil after biochar application did not change significantly under lower biochar treatment.The nitrogen-fixing bacteria in the experimental soil were mainly Proteobacteria,while the proportion of other nitrogen-fixing bacteria was small.(6)Biochar application inhibited the absolute abundance of fungi in soil.The fungal species richness and community diversity of the soil after the application of biochar were higher than those of the control group,which could be promoted at low dosage and inhibited at high dosage.Because the application of biochar changed the physical and chemical properties of the soil,it also caused changes in soil fungal community structure.This study provides a theoretical basis for the use of biochar.