烟秆生物质炭缓解连作植烟土壤间苯三酚积累和烟草黑胫病菌增殖的机制研究

Autotoxicity of phenolic acids play an important role in soil microenvironment imbalance which are main reason contributed toward the occurrence of continuous cropping obstacle. Biochar has greatly potential to alleviating continuous cropping obstacle, however alleviation mechanism of biochar on accumulation of autotoxicity of phenolic acids is unknown. Phloroglucinol, a typical autotoxins and accumulation character in tobacco-growing soil of different continuous cropping years, is selected as test material according to pervious research conclusions. And This project is proposed to study effect of tobacco stem biochar of different addition amount on adsorption and retention of phloroglucinol characters and some micro-ecological environment factors including root exudates, soil microbial quantity and structure of rhizosphere soil, and to discuss the accumulation law of phloroglucinol and its correlation with factors of soil microenvironment. Meanwhile, we will also measure the impact of tobacco stem biochar in different addition amount on growth of phytophthora parasitica var. nicotinanae which is a model soil-borne disease. and others some indexes in rhizosphere soil including bacterial population, communities structure, leaching liquor component and microbial population and communities will be evaluated. And we attempt to discuss between the effect of biochar on pathogen growth and its correlation with factors of soil microenvironment. In conclusion, the subject will be pinpoint an alleviating mechanism of soil microenvironment of tobacco stem biochar on accumulation of phloroglucinol in tobacco-growing soil and pathogen growth, enrich the research in alleviating mechanism of continuous cropping obstacle, and provide some theoretical support for practical application of tobacco team biochar.

土壤微环境失衡是连作障碍发生的主要原因，酚酸类自毒物质积累在其中扮演重要角色。生物质炭在缓解连作障碍方面具有较大潜力，但其缓解自毒物质积累的相关研究尚待加强。为此，本研究在前期研究结果基础上，选择连作植烟土壤中具有显著积累特征和自毒潜力的间苯三酚作为研究对象，拟通过外源添加方法，研究烟秆生物质炭不同添加量对间苯三酚在土壤中的吸附滞留特性、根系分泌物组分、土壤微生物数量及群落结构的影响，探讨生物质炭对间苯三酚积累规律及其与微生态环境因子的相关性。同时以烟草典型土传病害（烟草黑胫病）为例，研究烟秆生物质炭不同添加量对病原菌增殖、根系分泌物组分和微生物区系的影响，探讨烟秆生物质炭对病原菌增殖的影响及其与根际环境的相关性。通过项目实施，以期明确烟秆生物质炭对间苯三酚在连作植烟土壤中的积累特性和病原菌增殖的微生态缓解机制，丰富生物质炭缓解连作障碍机理，并为今后开展烟秆生物质炭的实际应用提供理论支撑。

土壤微环境失衡是连作障碍发生的主要原因，酚酸类自毒物质积累在其中扮演重要角色。生物质炭在缓解连作障碍方面具有较大潜力，但其缓解自毒物质积累的相关研究尚待加强。为此，项目在前期研究结果基础上，假设烟秆生物质炭可通过缓解土壤中自毒物质间苯三酚积累和黑胫病菌增殖进而缓解烟草连作障碍发生，通过定量控制间苯三酚添加量模拟连作后自毒物质积累土壤，探讨了烟秆生物质炭对间苯三酚的吸附滞留特性、土壤微生态主要环境因子以及黑胫病菌增殖的影响。主要研究结果表明：烟秆生物质炭能有效吸附土壤中的间苯三酚，其中以2.5%质量比的生物质炭施用量对间苯三酚的吸附量最高，10%生物质炭吸附率最大；烟秆生物质炭可显著改变原生土壤微生态环境，提高土壤酶活性，降低间苯三酚、对羟基苯甲酸等6种酚酸积累量，显著促进可培养细菌数量，提高微生物群落丰富度和多样性；烟秆生物质炭有利于改善烟株根际微生态环境，施用后根际土壤间苯三酚、对羟基苯甲酸、香草酸等自毒物质大幅度降低，根际土壤可培养细菌、真菌和放线菌数量增加，微生物丰富度、丰度和均匀性显著提高，有益微生物增多；综合研究结果提出烤烟施加烟秆生物质炭的最佳质量比为1%；室内抑菌试验表明，烟秆生物质炭可不同程度抑制黑胫病菌的生长、孢子囊产生量及游动孢子释放率；通过接种试验发现烟秆生物质炭可通过影响土壤理化指标，改变土壤中可培养微生物数量，微生物群落组成、结构和功能，间接抑制黑胫病菌的繁殖。研究结果将有助于进一步明确生物质炭缓解连作植烟土壤酚酸类自毒物质积累和土传病原菌增殖的微生态环境机制，同时也为今后科学利用生物质炭缓解连作土壤质量问题提供理论依据。项目共发表论文6篇，其中SCI收录论文1篇，国内一级学报1篇，核心期刊4篇，培养研究生5名。