The Effect Of Wheat-derived Biochar On The Respiration And Nitrogen Conversion In Soil

Biochar is mainly a carbon-rich solid with stable properties and complex structure prepared by limiting crop cracking of crop straw.Due to its rich functional groups and microporous structure,it is also used for environmental remediation of soils and waters,and it can adsorb heavy metals and organic pollutants in soil and water.Also.Due to its special physical and chemical properties and structural characteristics,biochar is often used as a soil amendment to increase soil carbon sinks,improve soil physical and chemical properties and related soil activity processes,such as increasing soil pH,inhibiting soil greenhouse gas emissions and Affect soil nitrogen conversion and so on.However,the quantitative research on the carbon and nitrogen conversion of soil by biochar is still very rare.In addition,the impact of biochar on soil carbon and nitrogen conversion after aging in soil is rarely seen.In this paper,wheat straw was used as biomass source to prepare biochar produced at different temperatures and the following studies were carried out:biochar was added to soil and sterilized soil,oxidized biochar was added to soil.Effects of respiration,denitrification,total nitrification rate,and rate of release of gaseous nitrogen oxides in the soil.The main conclusions are as follows:(1)The physical and chemical structure characteristics of wheat straw biochar are closely related to the cracking temperature.With the increase of preparation temperature,the pH value increases,the ash content decreases,the carbon aromaticity increases,the structure becomes clearer,and the pore structure develops more perfect.(2)The effect of biochar on soil is affected by soil microbes.Low temperature(?200?0C)pyrolysis of biochar will reduce soil pH,while higher temperature(?400?)dissociation of biochar can enhance soil.pH,and promote the increase of soil respiration rate,inhibition of soil nitrification,denitrification rate.This promotion or inhibition of biochar production at higher temperatures is stronger.The effect of biochar on respiration,nitrification and denitrification in sterilized soil was not significant in soil.(3)The alkalinity of biochar oxidation decreases,and the effect of oxidizing biochar into the soil decreases the pH of the soil.The oxidation of biochars at temperatures above 400? into the soil will still increase the pH of the soil.The biochar oxidation at 300? will increase the aeration of the soil and promote the improvement of soil respiration rate after 24 and 48 hours of oxidation;600? and The oxidation of biochar at 700? can significantly inhibit soil nitrification,denitrification rate and release rate of gaseous nitrogen oxides.(4)The addition of biochar to the soil can alleviate the decline of soil aeration caused by fertilization.WS500,WS600 and WS700 can significantly increase the respiration rate of fertilized soil and inhibit the release rate of gaseous nitrogen oxides;WS600 and WS700 enhance the soil.Organic nitrogen content.Low temperature(?300?)pyrolysis of biochar and nitrogen fertilizer will promote soil nitrification and denitrification,while higher temperature(?400?)dissociated biochar and nitrogen fertilizer significantly inhibit soil nitrification and denitrification.Although the effect of biochar oxidation on fertilized soil decreased after 24 hours,it still inhibited the release of gaseous nitrogen oxides from fertilized soil,and OWS600 could still increase the content of organic nitrogen in soil.