| Biochar is mainly carbon-rich particles obtained by high temperature thermal cracking of some animal and plant residues under oxygen-limited or anaerobic conditions.Due to the wide range of raw materials for biochar production and high conversion rate,it has broad application prospects in the fields of bioenergy production,waste recycling,greenhouse gas emission reduction and soil remediation.Biochar has high application value in the fields of soil remediation and improvement due to its excellent physicochemical properties,and which has been widely concerned by the academic community.For example,the acidity and alkalinity of biochar can be used to improve soil pH;the more soil organic carbon content increases soil fertility,and the soil microbial is affected by changing the structure of soil microbial community.The current research focuses on the related transformation of nitrogen and phosphorus in soil by biochar,and there is lack of research on sulfur.Sulfur is an indispensable element in plants and it is the fourth essential nutrient for plant growth after nitrogen,phosphorous,and potassium.It is an important component of some amino acids.Sulfur participates in the synthesis of chlorophyll,vitamin H and B,regulates the activity of enzymes in vivo,affects the nitrogen fixation of nitrogen-fixing bacteria,and it is also closely related to the cold and drought resistance of plants.In this paper,the different amounts of rice straw biochar were added into the soil and mixed evenly.There was set up three replicates for each sample,and it was treatment by flooded anaerobic.Then the samples were incubated at 25 ° C in an incubator for 15 weeks.Soil samples were taken at different times to determine their pH,conductivity,organic matter,urease,catalase,total sulfur,water-soluble sulfur,adsorbed sulfur,hydrochloric acid soluble sulfur and other properties.After 15 weeks the soil samples were taken for high-throughput sequencing to study microbial community structure information.The study had found the basic characteristics of rice straw biochar are directly related to its carbonization temperature.The carbonization temperature is high,the pH became high,the ash content became large,the sulfur element content became small,and the specific surface area became large.After 15 weeks of adding rice straw biochar culture had found:The soil pH increased in the first 6 weeks and decreased in the last 9 weeks.This is because of the high alkalinity of biochar,which has a great influence on the soil at the initial stage.When the times pass,the microbial activity is enhanced,and the anaerobic respiration produces acidic substances released into the soil,so the pH of the system is lowered.Due to the strong adsorption characteristics of biochar,the water-soluble ions in the soil are adsorbed,and the conductivity decreases after 15 weeks of cultivation.Both urease and catalase activities were inhibited.Sulfur is sensitive to the response for biochar.The addition of 1% biochar increased the total sulfur capacity.For adding 3% and 5% of biochar,and the increasing of total sulfur was weakened.The water-soluble sulfur content was decreased,the adsorbed sulfur content was increased,the soluble sulfur content of hydrochloric acid increased by added biochar 1% and 3%,and it became decreased by added biochar 5%.After 15 weeks,the high-throughput sequencing of paddy soil samples revealed that the results were found the total: 71 phylums,83 classes,161 orders,279 families and 615 genera.The Alpha diversity analysis indicated that the microbial community structure analysis found that the addition of rice straw biochar severely inhibited the activity of soil microbes.The high abundance of soil microbial and uniformity were decreased.The activity of proteobacteria was enhanced;the activity of gacteroidetes and gemmatimonadetes was also enhanced,and the activity of the firmicutes and tenericutes,were greatly enhanced.When chloroflex is applied with more amount of biochar,its activity became inhibited.The acidobacteria was directly inhibited by adding biochar.The desulfovibrionales,desulfobacterales and desulfuromonadales were found in soils.The desulfuromonadales were the largest contributor in SRB.The geobacter belong to geobacteraceae has made the biggest contribution to this order.The population is positively correlated with the amount of biochar addition,and the influence of BL600 is stronger than that of BL300.The SRB can transform sulfate,sulfite and thiosulfate in soil to hydrogen sulfide,which is weakly acidic and makes the soil pH value decrease.The watersoluble sulfur provides energy for the SRB,and its own consumption is reduced,which leads to a decrease in the water-soluble sulfur content of the system,and the population of the sulfurreducing bacteria increases,which is consistent with the experimental results. |
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