不同温度和水分培养对黑土有机碳含量及组成的影响

发布时间：2018-05-24 01:27

本文选题：温度 + 土壤含水量　；参考：《吉林农业大学》2015年硕士论文

【摘要】：全球变暖是如今人类社会广泛关注的焦点议题,由此引起的温度与降水的变化也必将对土壤有机碳含量及组成产生影响。本文通过室内培养试验,研究了未添加和添加玉米秸秆条件下不同温度(10、30和50℃)和水分(30%WHC、60%WHC、250%WHC),对土壤有机碳及其组分(团聚体有机碳、水溶性有机碳及腐殖质碳)含量以及腐殖物质结构特征的影响。为增强土壤固碳功能、缓解大气CO2浓度升高、促进农业可持续发展提供理论依据,主要研究结果如下:1、与未添加玉米秸秆的对照相比,添加玉米秸秆后,土壤总有机碳含量显著增加。随培养温度的增加,未添加和添加玉米秸秆处理的土壤总有机碳的顺序为10℃30℃50℃,这表明高温不利于土壤总有机碳的积累。随培养时间的延长,未添加和添加玉米秸秆处理的土壤总有机碳含量均降低。2、与未添加玉米秸秆的对照相比,添加玉米秸秆后,土壤易氧化有机碳含量显著增加。随培养温度的增加,未添加和添加玉米秸秆处理的土壤易氧化有机碳含量的顺序为10℃30℃50℃,这表明高温不利于土壤易氧化有机碳的累积。3、与未添加玉米秸秆的对照相比,添加玉米秸秆后,土壤中2~0.25 mm粒级团聚体的含量、土壤团聚体的平均重量直径(MWD)和几何平均直径(GMD)均显著增加,不稳定团粒指数(ELT)降低,这表明添加玉米秸秆能增加土壤团聚体的稳定性。随培养温度的增加,未添加和添加玉米秸秆处理的土壤中2~0.25 mm粒级团聚体的含量、土壤MWD和GMD的顺序10℃30℃50℃,土壤ELT依次为50℃30℃10℃,这表明高温不利于土壤大团聚体的形成,破坏了土壤团聚体的稳定性。随培养时间的延长,未添加玉米秸秆的处理,在10和30℃培养条件下,2~0.25 mm粒级大团聚体的含量、MWD和GMD均增加,土壤ELT降低;相反,在50培养条件下,土壤中2~0.25 mm粒级大团聚体的含量、土壤MWD和GMD均降低,而土壤ELT增加。添加玉米秸秆的处理,随培养时间的延长土壤中2~0.25 mm粒级大团聚体的含量、土壤MWD和GMD均降低,而土壤ELT增加。与未添加玉米秸秆的对照相比,添加玉米秸秆显著增加了土壤各粒级团聚体有机碳含量;随培养温度的增加,未添加和添加玉米秸秆处理的土壤各粒级团聚体有机碳含量呈降低的趋势,这表明高温不利于土壤团聚体有机碳的累积。随培养时间的延长,未添加和添加玉米秸秆处理的土壤各粒级团聚体有机碳含量均降低。4、与未添加玉米秸秆的对照相比,添加玉米秸秆以后,土壤水溶性物质(WSF)和腐殖质组分(可提取腐质物质-HE、胡敏酸-HA、富里酸-FA)碳含量均显著增加。随培养温度的增加,未添加玉米秸处理的WSFC含量均表现为50℃处理要显著高于10和30℃处理,添加玉米秸秆处理均表现10和50℃处理要显著高于30℃处理。随培养温度的增加,土壤HEC、HAC和FAC的含量依次为10℃30℃50℃,这表明,高温不利于土壤腐殖质有机碳的累积。随着培养时间的延长,除HAC有增加的趋势外,未添加和添加玉米秸秆土壤中水溶性物质和腐殖质组分的碳含量均有降低的趋势。添加玉米秸秆同时也增加了土壤腐殖物质的胡富比(CHA/CFA)、胡敏酸(HA)的logK和E465/E665值;随培养温度的增加,土壤腐殖物质的CHA/CFA、HA的logK和E465/E665值均有降低的趋势,这表明高温培养条件加快了HA分子结构的老化、减弱了它的胶体功能并降低了活性,同时使HA的分子结构变得复杂。随培养时间的延长,土壤腐殖物质的CHA/CFA有增加的趋势。5、不同水分培养试验研究结果表明,土壤总有机碳含量和腐殖质组分含量均随培养水分含量的增加而降低。其中250%水分处理和其他水分处理之间达到了差异的显著性水平。然而,土壤水溶性有机碳的含量随着土壤含量水量的的增加而显著增加。从固态C NMR波谱,可以看出土壤腐殖质中烷基C/烷氧C,脂族C/芳香C,疏水C/亲水C的比值,其中胡敏酸的这一比值表现为250%WHC30%WHC≈60%WHC,30%WHC≈60%WHC250%WHC和250%WHC60%WHC≈30%WHC;而胡敏素分别是:250%WHC30%WHC≈60%WHC,60%WHC≈250%WHC30%WHC和30%WHC≈250%WHC60%WHC。以上研究结果表明,土壤水分含量过高不利于土壤总有机碳和腐殖质组分的积累,促进了土壤水溶性有机碳的累积。虽然土壤水分含量对胡敏酸和胡敏素的化学成分的影响结果不一致,但这两种腐殖物质的烷基C/烷氧C的比值,均为高水分培养条件下要高于低水分培养条件。含水量较低的土壤水溶性有机碳含量更高,土壤胡敏酸和胡敏素分解程度更高,致使含水量较低的土壤有机碳含量高于含水量较高的土壤。我们的研究结果将会为理解土壤腐殖物质在特殊的土壤水分条件下的行为和机制提供理论依据。
[Abstract]:Global warming is the focus of widespread concern in human society. The changes in temperature and precipitation will also affect the content and composition of soil organic carbon. In this paper, the different temperatures (10,30 and 50 C) and water (30%WHC, 60%WHC, 250%WHC) and water (30%WHC, 60%WHC, 250%WHC) under the condition of adding and adding corn straw are studied in this paper. The content of soil organic carbon and its components (aggregate organic carbon, water soluble organic carbon and humus carbon) and the structural characteristics of humus can provide a theoretical basis for enhancing soil carbon sequestration, alleviating the increase of atmospheric CO2 concentration and promoting the sustainable development of agriculture. The main results are as follows: 1, as compared with the control of no corn straw added, the main results are as follows After adding corn straw, the total organic carbon content of soil increased significantly. With the increase of culture temperature, the order of total organic carbon in soil without adding and adding corn straw was 10 C 30 C 50 degrees C, which indicated that high temperature was not conducive to the accumulation of soil total organic carbon. With the extension of culture time, the total organic soil organic organic matter treated with corn straw was not added and added. The content of carbon decreased by.2. Compared with the control of corn straw, the content of oxidized organic carbon in soil increased significantly after adding corn straw. With the increase of culture temperature, the order of easy oxidation organic carbon content of soil without adding and adding corn straw was 10 C 30 C 50 degrees C, which indicated that high temperature was not conducive to soil easy to oxidize organic carbon. After adding corn straw, the content of 2~0.25 mm particle aggregate in soil, the average weight diameter (MWD) and the geometric mean diameter (GMD) of soil aggregate increased significantly, and the unstable aggregate index (ELT) decreased, which showed that adding corn straw could increase the stability of soil aggregates. The increase of culture temperature, the content of 2~0.25 mm particle aggregate in soil without adding and adding corn straw, the order of soil MWD and GMD at 10 degrees centigrade 30 and 50 degrees C, and the soil ELT in turn at 50 C 30 C 10 centigrade, indicating that the high temperature is not conducive to the formation of soil aggregates, and the stability of soil aggregates is destroyed. With the prolongation of the incubation time, no addition has been added. With the treatment of corn straw, the content of 2~0.25 mm particle size large aggregate, MWD and GMD increased, and the soil ELT decreased. On the contrary, the content of 2~0.25 mm grain grade large aggregates in the soil, the soil MWD and GMD decreased, and the soil ELT increased, and the treatment of corn straw added with the cultivation time extended soil under the 50 culture conditions. The content of 2~0.25 mm particle size large aggregate in soil, soil MWD and GMD decreased, and soil ELT increased. Compared with the control of corn straw, adding corn straw significantly increased the content of organic carbon in soil aggregates; with the increase of culture temperature, no adding and adding corn straw treated soil aggregates organic carbon. The content showed a decreasing trend, which indicates that high temperature is not conducive to the accumulation of organic carbon in soil aggregates. With the prolongation of culture time, the organic carbon content of soil aggregate aggregates in soil without adding and adding corn straw all decreased by.4. Compared with the control of no corn straw, the soil water soluble substance (WSF) and humus after Tian Jiayu straw were not added. The carbon content of the components (-HE, Hu Min acid -HA, -FA of fulvic acid) increased significantly. With the increase of culture temperature, the content of WSFC in the treatment without corn straw was significantly higher than that of 10 and 30 C at 50 C. The treatment of adding corn straw at 10 and 50 centigrade was significantly higher than that at 30 C. In addition, the content of HEC, HAC and FAC in soil was 10 C 30 C 50 degrees C, which showed that high temperature was not beneficial to the accumulation of organic carbon in soil humus. With the extension of culture time, the content of carbon in water soluble substances and humus components in the soil without adding and adding corn straw had a tendency to decrease except for the trend of increasing HAC. At the same time, the logK and E465/E665 values of soil humus Hu Fubi (CHA/CFA) and Hu Min acid (HA) were also increased. With the increase of culture temperature, the CHA/CFA of soil humus, logK and E465/E665 of the soil humus decreased, which indicated that the high temperature culture conditions accelerated the aging of the HA substructure, weakened its colloid function and reduced its activity. At the same time, the molecular structure of HA became complex. With the prolongation of the culture time, the CHA/CFA of soil humus had an increasing trend of.5. The results of different water culture tests showed that the total organic carbon content and the content of humus components in soil decreased with the increase of water content. Among the 250% water treatments and other water treatments, the content of soil organic carbon and humus components decreased. However, the content of water soluble organic carbon in soil increased significantly with the increase of soil water content. From the solid-state C NMR spectrum, the ratio of alkyl C/ alkoxy C, lipoid C/ aromatic C and hydrophobic C/ hydrophilic C in soil humus, and the ratio of humic acid to 250%WHC30%WHC 60%WHC, 30% The results of WHC 60%WHC250%WHC and 250%WHC60%WHC 30%WHC, respectively, 250%WHC30%WHC 60%WHC, 60%WHC 250%WHC30%WHC and 30%WHC 250%WHC60%WHC., showed that high soil moisture content was not beneficial to the accumulation of soil organic carbon and humus components, and promoted the accumulation of water soluble organic carbon in soil. The effect of water content on the chemical composition of humic acid and Hu Minsu is not consistent, but the ratio of alkyl C/ alkoxy C of these two humic substances is higher than low water culture condition under high water culture condition. The content of water soluble organic carbon in soil with low water content is higher, and the decomposition degree of soil Hu Min acid and huminin is higher, resulting in the higher degree of decomposition of soil and soil, resulting in the higher degree of decomposition of soil soil and humic acid. The organic carbon content of soil with low water content is higher than that of soil with higher water content. Our research results will provide a theoretical basis for understanding the behavior and mechanism of soil humus under special soil moisture conditions.
【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S153.6

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