Fungal Community Succession Under Influence Of Biochar In Cow Manure Composting

There are many disadvantages in traditional manure composting,such as slow fermentation efficiency,serious nitrogen loss and low quality and unstable property of product.Biochar has the characteristics of stable property,rich pore structure on surface and capacity of adsorption,so it can be used as amendment to ameliorate composting process and improve the quality of compost products.Fungi are important component of microbial community in composting process,which play an important role in fermentation of composting and effect the quality of compost product.However,the research on the community structure and succession of fungi in the compost with biochar is insufficient.In this study,cow manure and corn straw were used as raw materials,10%rice straw biochar was added to compost,and the physicochemical properties,nutrient content and fungal community structure during composting process were detected.The results have theoretical and practical value for enriching the knowledge of composting microorganisms under the influence of biochar and improving composting technology.The main findings are as follows:?1?The composting process lasted for 43 days.Temperature of two treatments varied in similar trend.The thermophilic phase began on the 3d and lasted for 24 days.Temperature was highest on 4d,which was 74.9?and 73.8?,respectively in BC and CK.Compared with CK,addition of biochar reduced the loss of moisture by about 10%;increased p H value by 0.01-0.19;decreased EC by 0.22-0.47;increased DOM by 1.70-7.44%;and increased GI by 22.58%.?2?Adding biochar enhanced the nitrogen retention and carbon transformation of composting.After composting,TN of biochar treatment was about 17%higher than that of CK,and the NO₃^--N content was lower about 40%,however biochar had little effect on NH₄⁺-N.Additionally,biochar was conducive to the formation of humus and the degradation of cellulose,so as to improve the quality of compost product.At the end of composting,TC and humic acid content of BC were34.1%,15.1%,increased by 14%and 5%respectively compared with CK.The degradation rate of cellulose,hemicellulose and lignin was 57.20%,49.71%,10.17%,reapectively,and cellulase activity was 34.41 mg glucose·g^-1 after composting process,respectively,which were higher than that of the CK.?3?The dominant fungal community of the two treatments belong to Ascomycete or Basidiomycete,and Sordariomycetes,Eurotiomycetes,Agaricomycetes were main dominant fungal communities.Morever,biochar has the most obvious effect on the community structure of fungi on genus level.In mesophilic phase,the dominant fungal communities of BC were Aspergillus and Gibberela,whereas Aspergillus occupied most dominant position in CK treatment,biochar decreased the relative abundance of Aspergillu significantly;In thermophilic phase,dominant fungi community in BC were Aspergillus,which in CK were Penicillium and Aspergillus;In the cooling phase,the dominant communities of BC included Myriococcum,Thermomyces and Mycothermus.For CK,besids these,unclassified Microascaceae also were dominant fungal community.Meanwhile,the relative abundance of Myriococcum in BC was significantly higher than that of CK.Although the dominant fungal communities of thermphilic phase remained high relative abundance in mature phase,Scedosporium quickly enriched and became one of main fungi.Biochar had a positive impact on the fungal diversity in the thermophilic phase,while had little effect on the fungal community structure in this phase.?4?The community structure of fungi changed significantly during composting,and there were significant differences between the two treatments in the indicator in each stage of composting.There were 15 and 14 fungal communities in CK and BC treatment,respectively,which can be used as indicators to indicate the composting process.Particularly,norank Pleosporales,norank Tremellales,Gibberella,Coprinopsis,Scedosporium and unclassified Sordariales were specific indicators in biochar treatment.?5?FUNGuild analysis showed that the main trophic mode of fungi in composting were saprotroph,pathotroph and symbiotroph,furthermore,saprotroph were main fungi promoting composting process.Biochar had the most significient effect on the distribution of trophic mode in thermophilic phase and cooling phase,and biochar had negative effect on saprotroph.Additionally,most of the pathotroph in material were killed acrossing composting.?6?The addition of biochar affected the correlation between fungal communities and environmental factors significiently.CCA analysis showed that the order of correlation between fungal community structure and phychemical factors was moisture concent>TC>DOM>C/N>p H>TN in BC;moisture concent>TC>DOM>C/N>p H>temperature>TN in CK.Biochar significantly reduced the correlation between fungal community structure and temperature,however,increased the correlation between fungal community structure and TC.Pearson correlation analysis showed that Aspergillus?amstelodami and Myriococcum?thermophilium were main fungi with high relative abundance during composting.Morever,Aspergillus?amstelodami were positively correlated with moisture content and DOM and negatively correlated with p H and TN.Myriococcum?thermophilium were positively correlated with p H,while were negatively correlated with C/N,moisture content,and DOM.