黑土区生物黑炭对土壤碳、氮转化及相关功能菌群多样性影响机制的研究

When applied to soil, biochar has the characteristics of higher stability against decomposition and excellent ability to absorb ions as compared to other forms of soil organic matter, due to its greater surface area, negative surface charge, and charge density. Recent research found that biochar was of great importance in increasing soil carbon storage, improving soil fertility, as well as maintaining the balance of soil ecosystems, and it could act as a kind of soil fertilizer or amendment to increase crop yield and plant growth by supplying and retaining nutrients. In the event that biochar becomes widely applied to agricultural soils as a soil conditioner, Hypothesized mechanisms for such a potential improvement are mainly enhanced water and nutrient retention (as well as improved soil structure and drainage). Furthermore, there is experimental evidence that soil microbial communities and their activity, which hold key roles in sustaining soil health and functioning, are directly affected by the addition of biochar to soils. The full range of mechanisms and consequences behind these effects remain poorly elucidated. Mollisols is taken for the experiment in the Heilongjiang Province. A controlled field experiment is designed to investigate carbon and nitrogen availability in soil microbial community structure in the presence and absence of biochar. Different sources of straw of wheat, corn, soybean, and maize will be used for the effects of biochar on carbon, nitrogen transformation and the related functional bacteria community structure, as well as the different amounts of biochar, 0, 20, 40, 60t ha-1. Bacterial communities were investigated in both the rhizosphere and bulk soil using biolog, PFLA coupled with a 454 new generation sequencing database. The key functional bacteria community will be investigated. The results will detect the effect mechanisms of biochar application to the soil on carbon and nitrogen availability, providing the basic knowledge for the mechanism that increase the soil carbon sequestration and decrease the amount of nitrogen fertilizer input under biochar application to the Mollisols.

生物黑炭（Biochar,BC）是作物秸秆经过高温热解而成的一种高度碳化的多孔物质，其施入土壤能够提高土壤肥力并能减少温室气体排放。BC被作为土壤改良剂应用逐渐被人认可，但其应用机制特别是BC对氮素有效性和根际微生物的影响机理尚不明确，影响其推广应用。本研究采用不同来源秸秆（小麦、玉米、大豆和水稻）制成BC，采用不同的施用数量，研究黑土区BC对土壤碳、氮转化速率、转化过程生化强度和最终有效态积累量的影响；并基于BC对NH4+-N吸附、淋溶及NO3-N淋溶累积损失的影响和对土壤中活性有机碳的影响探讨导致生物黑炭对土壤碳、氮有效性产生影响的原因；同时采用Biolog、PFLA结合454焦磷酸高通量测序技术分析土壤与碳、氮转化相关的功能菌群多样性的变化，揭示碳、氮转化过程中起主导作用的菌群及其功能。该研究为黑土区BC的"增碳减氮"效应提供科学理论依据，并促进BC的深入开发利用。

黑龙江省黑土区是我国重要的粮食生产基地，但随着开垦年限的增加黑土有机质下降问题越来越严重，耕作层中的有机质更以每年0.01%的速度下降（赵兰坡, 2006）。同时，大量秸秆资源未被利用，就地焚烧现象时有发生。如何利用秸秆资源又培肥地力，针对这一问题科研工作者提出了生物炭转化秸秆还田技术（潘根兴等, 2010;陈温福等, 2011; Luo et al.2013）。.生物炭（Biochar），也称为生物黑炭，是有机质（包括作物秸秆、畜禽粪便等）在缺氧条件下热分解的产物，会影响营养物质的转化（DeLuca et al. 2009; Major et al. 2010），但机制尚不明确。以不同来源秸秆制备生物炭为材料，研究黑土区生物炭添加对土壤碳氮转化过程强度、碳氮的最终积累量及其相关微生物数量、多样性的影响，探讨生物炭对土壤碳氮积累影响的可能原因，并通过高通量测序技术研究生物炭施用后土壤细菌群落结构的变化。主要研究结果如下：采用不同秸秆类型制备的生物炭对土壤碳氮转化过程的影响研究发现，生物炭的不同来源影响其在土壤中作用的发挥，同时，这种影响因大豆生育时期的不同呈现不同的规律，水稻源生物炭较同样数量的小麦源和玉米源生物炭对土壤有机质的提升更为显著；生物炭主要影响大豆生育前期土壤活性有机碳水平，对生育后期（结荚期、鼓粒期和成熟期）土壤活性有机碳的影响不显著；生物炭对土壤轻组有机质的影响与秸秆来源无关；随着生物炭施用数量的增加土壤有机质含量显著增加，其中10%质量比添加生物炭对土壤有机质的提升最为显著，但不同施用数量进行比较时发现，生物炭对土壤养分转化具有一定剂量效应，5%质量比对土壤氮素的活化最为有利；生物炭减缓土壤铵态氮、硝态氮的淋溶，铵态氮和硝态氮主要集中在0-20cm；生物炭添加改变根际土壤微生物的组成比例，改变细菌和真菌门水平和属水平的种类比例，显著促进如伞菌等有益微生物的比例，说明生物炭对构建健康土壤环境更为有利。.项目提供大量翔实数据，建立土壤碳氮转化过程的数据网络，为建立黑土区生物炭转化还田技术奠定坚实的理论基础。