厌氧和好气条件下作物秸秆的腐解特征研究

发布时间：2018-07-02 22:59

本文选题：作物秸秆 + 厌氧和好气条件　；参考：《安徽农业大学》2015年硕士论文

【摘要】：秸秆还田是维持和提高土壤肥力和作物产量的有效途径之一。土壤水分状况是作物秸秆腐解过程中最重要的影响因子,秸秆还田对土壤肥力的提升虽已有研究,但对于厌氧和好气条件下作物秸秆腐解差异的研究少有报道。本研究采用网袋培养方法,通过室内培养结合田间试验研究小麦、水稻、玉米和油菜秸秆在厌氧和好气条件下的质量残留量与碳、氮释放量及纤维素、半纤维素和木质素的残留量的变化特征,运用傅里叶变换红外光谱(fourier transform infrared spectroscopy,FTIR)技术,定性分析作物秸秆在厌氧和好气条件腐解过程的组分及结构变化特征。主要结果如下:1、作物秸秆的腐解均呈前期腐解快,中期变慢,后期稳定的趋势。在培养开始的前30天内,秸秆残留质量均显著性降低(P0.05),在30~(-1)80天内,缓慢下降,在180-360天,秸秆残留质量变化保持稳定。厌氧条件秸秆累积腐解率在56.52%-75.23%,好气条件秸秆累积腐解率在75.61%-83.63%。秸秆碳、氮残留量均随培养时间延长而降低,厌氧和好气条件秸秆碳释放率分别在80.77%-91.11%和86.56%-97.16%,秸秆氮释放率分别在62.23%-92.14%和69.64%-92.15%之间。秸秆中半纤维素、纤维素和木质素残留量整体呈下降趋势。由于秸秆在田间和室内的腐解规律呈现一定相似性,本文以室内结果为代表着重分析。2、小麦秸秆在好气和厌氧条件的残留质量、碳和氮残留量均随培养时间的延长而降低,且呈前期(0~3个月)降解较快,而后(3~12个月)逐渐减缓的趋势。用一级动力学方程(y=y0+a·e-kt)对小麦秸秆在好气和厌氧条件的残留质量随时间变化进行拟合(决定系数R2均大于0.957),质量腐解半衰期分别为72.8和121.9 d,腐解速率常数(k)分别为0.022 0和0.014 0/d。在好气条件,小麦秸秆中碳和氮元素释放速率常数分别是其在厌氧条件的1.79和1.67倍,小麦秸秆中碳和氮元素的释放率分别是其在厌氧条件的4.39和1.40倍,且在培养至1个月时处理之间呈显著性差异(P0.05)。小麦秸秆中的纤维素、半纤维素和木质素残留量均随培养时间延长呈下降趋势。以上结果表明,好气条件更有利于小麦秸秆碳氮元素的释放,及纤维素、半纤维素和木质素的降解,从而更有利于小麦秸秆的降解。4、水稻秸秆还田后,腐解速率表现为前期快、后期较慢的规律。在360 d培养时间内,厌氧和好气条件下的水稻秸秆腐解率分别为66.44%和71.41%,一级动力学对水稻秸秆质量残留进行拟合,腐解速率常数(k)分别为0.019×d~(-1)和0.020×d~(-1),腐解半衰期分别为71.41 d和58.8 d。在厌氧和好气条件下,水稻秸秆的碳释放率分别为76.89%和83.81%,碳释放半衰期别为56.90 d和54.20 d。水稻秸秆中氮的释放率分别为66.37%和72.16%,水稻秸秆在厌氧条件下的氮残留量比其在好气条件下高20.81%。随着培养时间的延长,水稻秸秆的纤维素、半纤维素和木质素残留量呈降低趋势,培养结束时,厌氧条件下秸秆半纤维素、纤维素和木质素腐解率分别为91.06%、90.00%、63.09%,均低于好气条件(95.06%、91.34%、66.76%)5、玉米秸秆各种组分的残留量随培养时间延长呈下降趋势,且前期(0~90天)腐解快,后期(90~360天)变慢。一级动力学方程对玉米秸秆质量残留率的拟合结果表明,厌氧和好气条件下玉米秸秆腐解半衰期分别为79.87天和52.89天。厌氧条件下玉米秸秆碳释放速率常数k0(0.545/天)低于其在好气条件下的k0(0.565/天),好气条件下玉米秸秆氮的累积释放率(74.20%)高于厌氧条件(71.42%)。随着培养时间的延长,玉米秸秆的纤维素、半纤维素和木质素残留量呈降低趋势。在360天内,好气条件更有利于玉米秸秆碳、氮元素的矿化和纤维素、半纤维素和木质素的腐解,且随着时间的延长差异减小。3、油菜秸秆还田后,腐解速率表现为前期快、后期较慢的规律。在360 d培养时间内,厌氧和好气条件下的油菜秸秆腐解率分别为60.50%和68.20%,腐解速率常数(k)分别为0.004×d~(-1)和0.010×d~(-1),腐解半衰期分别为229 d和117 d。在厌氧和好气条件下,油菜秸秆的碳释放率分别为70.33%和77.43%,厌氧条件下的释放速率常数(0.025×d~(-1))低于好气条件(0.026×d~(-1))。油菜秸秆中氮的释放率分别为82.20%和87.48%,油菜秸秆在厌氧条件下的氮残留量比其在好气条件下高38.25%,且达到显著性差异水平(P0.05)。厌氧条件下的氮残留率始终高于好气条件下,且在60~90 d培养期内差异最大。6、不同作物秸秆腐解培养之前的红外光谱在波数为3417cm~(-1)、2922cm~(-1)、1376cm~(-1)、1052cm~(-1)处均有的吸收峰,不同秸秆吸收峰的吸收强度虽有不同,但都表明小麦、油菜、玉米、水稻秸秆中含有水溶性物质,包括单糖、多糖、蛋白质、氨基酸等。随培养时间的延长,秸秆红外光谱图在波数为3 430~3 410 cm~(-1)(羟基的伸缩振动)、2 930 cm~(-1)(亚甲基的伸缩振动)处、2855cm~(-1)(甲基的伸缩振动)处的吸收峰吸收强度均有降低,表明秸秆中的碳水化合物减少,脂肪族特征下降。波数为1740 cm~(-1)、1 419~1 425 cm~(-1)处吸收峰吸收强度的降低,秸秆木质素含量略有下降,且厌氧条件下的吸收强度整体高于其在好气条件下。厌氧条件下,在780~800 cm~(-1)和468-475 cm~(-1)处(硅酸盐和Si O2等无机硅化物的吸收带)的吸收强度均高于好气条件的值。以上结果表明,秸秆腐解过程中脂族性下降,芳构化程度增强。好气条件下有利于秸秆中纤维素、半纤维素和脂肪族化合物的分解,提高其芳香性。
[Abstract]:Straw returning is one of the effective ways to maintain and improve soil fertility and crop yield. Soil moisture is the most important factor in the process of crop straw decomposition. Although straw returning to soil fertility has been studied, there are few reports on the difference of crop straw decomposition under anaerobic and aerobic conditions. This study is used in this study. In the field experiment, the quality residue of wheat, rice, corn and rape straw under anaerobic and aerobic conditions and the change characteristics of carbon, nitrogen release and cellulose, hemicellulose and lignin residues were studied by indoor culture and field experiments. Fourier transform infrared spectroscopy (Fourier transform infrared spectroscopy) was used. FTIR) technology, qualitative analysis of the components and structural changes of crop straw in anaerobic and aerobic conditions. The main results are as follows: 1, the decomposition of crop stalks is fast, slow and stable in the middle period. The residue quality of straw is decreased significantly in the first 30 days of culture (P0.05), and in 80 days of 30~ (-1). In the 180-360 day, the residue quality of straw remained stable. The accumulation rate of straw accumulated in anaerobic condition was 56.52%-75.23%, and the accumulation rate of straw accumulation was in 75.61%-83.63%. straw carbon, and the residue of nitrogen decreased with the prolongation of culture time. The carbon release rate of straw in anaerobic and aerobic conditions was in 80.77%-91.11% and 86.56%-97.16%, respectively. The nitrogen release rates of stem nitrogen were between 62.23%-92.14% and 69.64%-92.15%, respectively. The residue of hemicellulose, cellulose and lignin in straw showed a downward trend as a whole. Due to the similarity of the decomposition rule of straw in the field and indoor, the residue quality of.2 and wheat straw in aerobic and anaerobic conditions was emphatically analyzed in this paper. The residue of carbon and nitrogen decreased with the prolongation of the incubation time, and the degradation was faster in the early period (0~3 months) and then gradually slowed down (3~12 months). The residual mass of wheat straw in the aerobic and anaerobic conditions was fitted with time (y=y0+a. E-kt) with the first order kinetic equation (the determining coefficient R2 was greater than 0.957), and the mass decay was semi decaying. The decomposition rate constants (k) were 0.0220 and 0.014 0/d. respectively at 0.0220 and 0.014 0/d., respectively, and the rate constant of carbon and nitrogen release rate was 1.79 and 1.67 times in the anaerobic condition, respectively. The release rate of carbon and nitrogen in wheat straw was 4.39 and 1.40 times in the anaerobic condition, respectively, and during the incubation to 1 months. There was a significant difference between the treatments (P0.05). The cellulose, hemicellulose and lignin residues in wheat straw were all decreased with the prolongation of the culture time. The above results showed that the aerobic condition was more beneficial to the release of carbon and nitrogen elements of wheat straw, and the degradation of cellulose, hemicellulose and lignin, which was more beneficial to the reduction of wheat straw. After the rice straw was returned to field, the rate of decomposition of rice straw was fast in the early stage and later slower in the later period. In the 360 d culture time, the decomposition rate of rice straw under anaerobic and aerobic conditions was 66.44% and 71.41% respectively. The first order kinetics fitted the residue of rice straw mass, and the rate constant of decomposition rate (k) was 0.019 * d~ (-1) and 0.020 * d~ (-1), respectively. The carbon release rates of rice straw were 76.89% and 83.81% in the anaerobic and aerobic conditions, respectively, with the half-life of 71.41 D and 58.8 D. respectively. The release rates of nitrogen in the carbon release half-life of 56.90 D and 54.20 D. rice straw were 66.37% and 72.16% respectively. The nitrogen residue of rice straw under the anaerobic condition was higher 20.81%. than that under the aerobic condition. The cellulose, hemicellulose and lignin residue of rice straw showed a decreasing trend. At the end of culture, the decomposition rate of cellulose and lignin was 91.06%, 90%, 63.09%, respectively, under anaerobic conditions, respectively, which were lower than those of aerobic conditions (95.06%, 91.34%, 66.76%) 5, and the residue of various components of corn straw was followed by culture. The decaying between the early (0~90 days) and the later period (90~360 days) was slower. The fitting results of the first order kinetic equation to the residue of corn straw showed that the half-life of corn straw decomposition under anaerobic and aerobic conditions was 79.87 days and 52.89 days respectively. The carbon release rate constant of maize straw under anaerobic strip was lower than that of K0 (0.545/ days). The cumulative release rate of maize straw nitrogen (74.20%) under aerobic conditions (74.20%) was higher than that of anaerobic condition (71.42%). The cellulose, hemicellulose and lignin residues of corn straw decreased with the incubation time. In 360 days, the aerobic condition was more beneficial to the mineralization of maize straw carbon and nitrogen elements. The decomposition of cellulose, hemicellulose and lignin decreased by.3, and the rate of decomposition of rape straw was fast in the early stage and later in the later period. In the 360 d culture time, the decomposition rate of rape straw under anaerobic and aerobic conditions was 60.50% and 68.20% respectively, and the decomposition rate constant (k) was 0.004 x d~ (-1), respectively. And 0.010 * d~ (-1), the half-life of the decomposition was 229 D and 117 D. respectively under anaerobic and aerobic conditions. The carbon release rate of rape straw was 70.33% and 77.43% respectively. The release rate constant (0.025 x d~ (-1)) under anaerobic conditions was lower than that of aerobic condition (0.026 * d~ (-1)). The nitrogen release rate of rape straw was 82.20% and 87.48% respectively, and the rape straw was in anaerobic strip. The residual nitrogen content under the aerobic condition was 38.25% higher than that under the aerobic condition (P0.05). The nitrogen residue rate under the anaerobic condition was always higher than that under the aerobic condition, and the maximum difference was.6 in the 60~90 d culture period. The infrared spectra of the different crop straw decomposing culture were 3417cm~ (-1), 2922cm~ (-1), 1376cm~ (-1), 1052cm~ (-1), 1052cm~ (- 1052cm~ (-). 1) the absorption peak of the absorption peak, although different absorption peaks of different straw absorption peaks, showed that wheat, rape, corn, rice straw contained water soluble substances, including monosaccharides, polysaccharides, proteins, amino acids, etc. with the prolongation of the culture time, the infrared spectra of straw were 3 430~3 410 cm~ (-1), 2930 cm~ (-1 (Ya Jiaji's telescopic vibration), the absorption peak absorption strength of 2855cm~ (-1) (methyl expansion vibration) was reduced, indicating that carbohydrates in the straw were reduced and the aliphatic characteristics decreased. The wave number was 1740 cm~ (-1), the absorption peak absorption intensity at 1 419~1 425 cm~ (-1) decreased, the straw lignin content decreased slightly and under anaerobic conditions. The absorption strength was higher than that under aerobic conditions. Under anaerobic conditions, the absorption strength of the 780~800 cm~ (-1) and 468-475 cm~ (-1) (silicate and Si O2 and other inorganic silicides) was higher than that of the aerobic condition. The above results showed that the lipid property decreased and the aromatization degree increased in the process of straw decomposition. The condition of aerobic condition was beneficial to the straw. The decomposition of cellulose, hemicellulose and aliphatic compounds in culms improves their aromaticity.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S141.4

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