Influences Of Soil Microbial Community And Organic Nitrogen Under The Long-term Application Of Biochar And Three Organic Resources

Organic fertilizer or mineral fertilizer application separately cannot efficient and sustainable maintain soil productivity has been proved by many studies.The soil is becoming barren after long-term mineral fertilizer application,soil fertilized with mineral fertilizer and organic manure could promote soil nutrient becoming more and more consensus.Because of well structure and properties,being one kind of new type of soil conditioners and also used as the good matrix of slow release fertilizer,Biochar(BIO)attracts strongly impact.Traditional organic fertilizer piggery manure(PMC)and corn straw-returning(CS)as controls,based on the brown soil improvement field trial which in Shenyang Agriculture University,4 treatments is set,including biochar-based compound fertilizer(BF)and PMC,CS,BIO with NPK mineral fertilizers for the nutrient equally.This study by contrasting soil microbial community structure,inter-annual variability of different brown soil organic nitrogen components and changes of soil nutrients along with growth period explores the biological mechanisms of soil fertility,soil nutrient release and soil nitrogen supply potential by BIO and other organic fertilizers application for 7 years,to provide the theoretical basis of BIO and BF's large area promotion.The main results show that:1.Compared with the pre-test,BF and BIO increase soil chemical nutrient and pH,BF has an advantage in soil porosity and BIO in yield.In the northeastern typical brown soil peanut for growing crops conditions with the same amount of total NPK,treatment BF and CS showed a similar trend and change on most indexes.Treatment BIO performed better than CS and BF on Olsen P,available K,total P and yield that means biochar is better than CS which is the source of biochar in improving soil such like P,K and increasing yield(the amount of biochar input in this experiment is determined by the amount of straw applied).The pig manure compost was applied to improve the soil can play a role in water retention on one side,on another the available NPK will not decline when moisture content reduce,that's saying pig manure compost has benefit on water and fertilizer retention.2.Different organic matters for long-term fixed fertilization make the soil biomass marked by PLFA of different types of micro flora differentiation,the treatment PMC have the highest biomass of different types of micro flora and total biomass,BIO increase the biomass of bacteria and actinomycetes and BF increase the biomass of fungi and actinomycetes too contrasting with CS.Puting in order through redundancy and correlation analysising,there is a significant correlation between soil microbial biomass and soil physical and chemistry properties i.e.pH,total N(TN),soil organic matter(SOM),moisture content and total K(TK).Different amount and types of biochar can cause different soil microbial community biomass,treatment BF is good for accumulating fungi and gram negative bacteria and abundant the soil microbial comrmunity.3.Compared with the year 2009,for seven years' fixed application of different organic resources,acid hydrolysable organic N(AHON),ammonia N(AN),amino acid N(AAN)and amino sugar N(ASN)has been significantly improved,hydrolysable unknown N(UN)and non hydrolysable N(NHN)do not change significantly.Long-term application of organic fertilizers can improve the content of soil organic nitrogen components,the effect on different components of organic nitrogen depends on fertilizer species,treatment BF contributes to the improvement of AN and AAN reducing NHN meantime,treatment BIO and PMC contributes to the improvement of AAN,and BIO reducing HUN,BIO or BF could increase soil organic nitrogen storage capacity and update soil nitrogen by long-term applied,illustrating that BIO and BF long-term mechanism of fertilizing soil;all treatments contribute to the improvement of ASN:ASN could be improved by long-term's organic fertilizer application including BIO and BF,and has significant correlation with bacteria,actinomycetes,gram positive bacteria and gram negative bacteria PLFAs,the enhance of ASN increases soil organic nitrogen capacity;the contents of different components of organic nitrogen fractions in all treatments displayed an order of AN>AAN>NUN>HUN>ASN.