秸秆直接还田与炭化还田下稻田土壤性质、水稻生长及温室气体排放变化

发布时间：2018-04-24 21:54

本文选题：秸秆还田 + 生物质炭　；参考：《南京农业大学》2015年硕士论文

【摘要】：生物质炭是各类生物质在缺氧状况下热裂解产生的一类高度芳香化难溶固态物。生物质炭施入土壤后可以改善土壤性质、提高作物产量,并且减少温室气体排放,但生物质炭的影响因土壤类型、气候条件和生物质炭的性质而呈现较大差异。本文以太湖地区稻田土壤生态系统为对象,研究了秸秆直接还田及其炭化生成生物质炭后再还田对稻田生态系统土壤性质、作物生长和温室气体排放的影响。试验设置4个处理,分别为:常规对照(CK),秸秆还田(SR),小麦秸秆生物质炭(WBC)和水稻秸秆生物质炭(RBC)还田。秸秆还田为全量还田,生物质炭用量为20thm-2。同时,为了研究生物质炭与氮肥施用的交互作用,试验还设置了氮肥处理(氮肥用量为0和300 kghm-2)。主要研究结果如下:①与常规管理模式(CK)相比,秸秆直接还田(SR)和炭化后再还田(WBC和RBC)对水稻穗粒数和千粒重等产量构成因子没有显著影响,但通过增加水稻分蘖数或单株生物量改变了水稻收获时期地上部生物量和水稻产量。氮肥施用对水稻穗粒数和千粒重也没有影响,但显著增加了水稻地上部生物量和产量。在施用氮肥处理中,RBC处理增加了水稻地上部生量和产量,而WBC只增加了水稻地上部生物量。②秸秆还田和生物质炭还田显著改变了土壤性质。与常规对照(CK)相比,施用生物质炭处理提高了土壤有机碳含量、速效钾含量,但降低容重。氮肥施用,对土壤有机碳含量、速效钾含量、容重和土壤铵态氮含量没有显著影响。在不施氮素(N0)情况下,秸秆还田处理的硝态氮显著高于其他处理。③秸秆还田和生物质炭还田对温室气体排放通量的影响因气体种类不同而有所差异。秸秆还田处理显著提高了稻田土壤CH4和CO2的排放,与秸秆还田处理相比,施用水稻生物质炭和小麦生物质炭处理显著降低了 CH4和N2O排放。与常规对照相比,其它处理均降低了土壤N2O的排放。炭化还田显著降低了稻田温室气体排放强度(GHGI)。综上所述,与常规管理模式(单纯施用化学肥料)相比,秸秆直接还田和经炭化后再还田会改变土壤理化性质、作物产量和温室气体的排放量。本研究结果表明,尽管秸秆直接还田是目前秸秆处理的主要方式,但其对土壤增肥、作物增产的贡献十分有限,且秸秆还会显著促进温室气体,特别是甲烷的排放。与之相比,作物秸秆经炭化制成生物质炭后再还田,可以显著提高土壤肥力水平,增加作物产量,并显著降低温室气体的排放量。
[Abstract]:Biomass charcoal is a kind of highly aromatizing and insoluble solid matter produced by pyrolysis of various biomass under anoxic condition. Applying biomass carbon into soil can improve soil properties, increase crop yield and reduce greenhouse gas emissions. However, the effects of biomass carbon on soil types, climate conditions and biomass carbon properties vary greatly. In this paper, the effects of straw returning directly to the paddy field and its carbonization to biomass carbon and then returning to the field on the soil properties, crop growth and greenhouse gas emissions of paddy field ecosystem in Taihu Lake region were studied. Four treatments were set up in the experiment, which were CK, SRC, WBCand RBC, respectively. The total amount of straw was returned to the field, and the amount of biomass carbon was 20thm-2. At the same time, in order to study the interaction between biomass carbon and nitrogen fertilizer, the treatment of nitrogen fertilizer (0 and 300kghm-2) was set up in the experiment. The main results were as follows: (1) compared with the conventional management model (CK), the direct return of straw to the field (SRS) and carbonization before returning to the field (WBC and RBC) had no significant effects on the yield components such as grain number per panicle and 1000-grain weight. However, the aboveground biomass and rice yield were changed by increasing the number of tillers or biomass per plant. Application of nitrogen fertilizer had no effect on grain number per spike and 1000-grain weight, but significantly increased the aboveground biomass and yield of rice. In the application of nitrogen fertilizer, RBC treatment increased the aboveground growth and yield of rice, while WBC only increased the aboveground biomass of rice. 2. 2 straw and biomass carbon significantly changed the soil properties. Compared with CK, biomass carbon treatment increased soil organic carbon content and available potassium content, but decreased bulk density. Nitrogen application had no significant effect on soil organic carbon content, available potassium content, bulk density and soil ammonium nitrogen content. In the absence of N _ 0), the effects of straw returning on greenhouse gas emission flux were significantly higher than that of other treatments. 3. The effects of straw returning and biomass carbon returning on greenhouse gas emission fluxes were different with different gas types. Compared with straw returning treatment, rice biomass carbon treatment and wheat biomass carbon treatment significantly reduced CH4 and N 2O emissions. Compared with the conventional control, the other treatments reduced the emission of N 2O from soil. The intensity of greenhouse gas emission in paddy field was significantly reduced by carbonization. To sum up, compared with the conventional management mode (simple application of chemical fertilizer), the direct return of straw to the field and the return to the field after carbonization will change the physical and chemical properties of the soil, crop yield and greenhouse gas emissions. The results showed that straw returning directly to the field was the main way of straw treatment at present, but its contribution to soil fertilizer and crop yield was very limited, and straw could significantly promote the emission of greenhouse gas, especially methane. In contrast, crop straw can be carbonized into biomass carbon and then returned to the field, which can significantly improve soil fertility, increase crop yield and significantly reduce greenhouse gas emissions.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511;S141

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