秸秆还田对土壤有机质元素组成及化学结构的影响

发布时间：2018-06-18 06:46

本文选题：秸秆还田 + 有机质　；参考：《安徽农业大学》2016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重要措施之一。近年来,秸秆还田措施的推广促进了农田土壤有机质(Soil Organic Matter)水平的快速增长,但是农作物秸秆还田不仅可以促进土壤有机质积累,还会影响土壤有机质的结构变化。因此探究秸秆还田后对土壤有机质化学结构方面的影响对我国的农业资源的可持续利用具有重要意义。本研究采用田间试验和室内模拟相结合的方法,运用傅里叶变换红外光谱(Fourier Transform Infrared Spectroscopy,FTIR)和固态核磁共振技术技术(Solid State Nuclear Magnetic Resonance,NMR)分析作物秸秆在不同还田模式下对土壤碳氮含量,土壤有机质元素组成及其化学结构的影响。主要结果如下:1)田间试验结果表明,秸秆还田能够显著增加土壤碳、氮含量。与空白处理相比较,秸秆还田后土壤有机质的含量提高了4%-16%,土壤全氮含量提高了3%-17%。农作物秸秆还田对土壤有机质的化学结构产生明显的影响。傅里叶变换红外光谱结果显示,小麦和玉米秸秆还田增加了SOM中的酰胺物质的含量(1655cm-1/1550cm-1),且玉米秸秆还田后SOM中酰胺物质的含量要明显高于小麦秸秆还田后SOM中酰胺物质的含量。固态核磁共振图谱表明,小麦和玉米秸秆还田能够增加SOM中烷氧碳的相对含量,降低SOM中芳基碳的相对含量。玉米秸秆还田后SOM的芳香度要高于小麦秸秆还田后SOM的芳香度。2)室内试验结果表明,与0天相比较,在好氧和厌氧条件下小麦秸秆还田360天后土壤有机碳的含量分别提高了37.8%和48.1%。但是土壤全氮的含量分别降低了5%和9%。元素分析结果表明,好氧和厌氧条件下小麦秸秆还田后SOM、POM(Particulate Organic Matter)500-53μm的C/N比下降。POM 500-53μm的C/N比值要明显高于POM 53μm的C/N比值。固态核磁共振图谱表明,在好氧条件下SOM、POM 500-53μm和POM 53μm中烷氧碳的相对含量较高,而烷基碳的相对含量较低。而在厌氧条件下,小麦秸秆还田后SOM、POM 500-53μm和POM 53μm中烷基碳的相对含量较多,烷氧碳的相对含量较少。小麦秸秆和玉米秸秆还田能够提高土壤有机质中烷氧碳的相对含量,并且玉米秸秆还田后SOM中的酰胺含量和芳香度都要高于小麦秸秆还田后SOM中的酰胺含量和芳香度。不同的水分管理条件下小麦秸秆降解影响了SOM和POM的化学结构。好氧条件下,秸秆还田后增加了SOM,POM 500-53μm,POM 53μm中烷氧碳的相对含量,而厌氧条件下,秸秆还田后增加了SOM,POM 500-53μm,POM 53μm中烷基碳烷氧碳的相对含量。
[Abstract]:Straw returning is one of the important measures to maintain and improve soil fertility and crop yield. In recent years, the promotion of straw returning measures has promoted the rapid growth of soil organic matter (Soil Organic Matter) level in farmland, but crop straw returning can not only promote the accumulation of soil organic matter, but also affect the structure change of soil organic matter. Therefore, it is of great significance to explore the effects of straw returning to the chemical structure of soil organic matter to the sustainable utilization of agricultural resources in China. This study uses the method of combining field experiments and indoor simulation, using Fourier transform infrared spectroscopy (Fourier Transform Infrared Spectroscopy, FTIR) and solid-state nuclear magnetic resonance technique. Solid State Nuclear Magnetic Resonance (NMR) was used to analyze the effects of crop straw on the soil carbon and nitrogen content, the composition of soil organic matter elements and its chemical structure in different returning fields. The main results are as follows: 1) the field test results show that straw returning can significantly increase soil carbon and nitrogen content. Compared with the blank treatment, the straw is compared with the straw. After returning to the field, the content of soil organic matter increased by 4%-16%. The total nitrogen content of soil increased by 3%-17%. crop straw returning to the chemical structure of soil organic matter. The results of Fourier transform infrared spectroscopy showed that wheat and corn straw returning to the field increased the content of amides in SOM (1655cm-1/1550cm-1) and corn straw. The content of amides in SOM after returning to field was significantly higher than the content of amides in SOM after wheat straw returned to field. The solid-state nuclear magnetic resonance spectrum showed that the relative content of alkoxy carbon in SOM could be increased and the relative content of aryl carbon in SOM was reduced. The aromatic degree of SOM after returning to field of maize straw was higher than that of wheat straw. After returning to the field, the aromaticity of SOM.2) laboratory test results showed that the soil organic carbon content increased by 37.8% and 48.1%. after 360 days of aerobic and anaerobic conditions, but the total nitrogen content of soil decreased by 5% and 9%. elements respectively, and the wheat straw was returned to the field under aerobic and anaerobic conditions after returning to the field SOM. The C/N ratio of POM (Particulate Organic Matter) 500-53 mu m is significantly higher than the POM 53 micron m C/N ratio. The solid-state nuclear magnetic resonance spectrum indicates that the relative content of the alkoxy carbon is higher and the relative content of alkyl carbon is lower in the aerobic condition, and the relative content of alkyl carbon is lower. In the anaerobic condition, the wheat straw is in the anaerobic condition. After returning to the field, the relative content of alkyl carbon in SOM, POM 500-53 and POM m is more, the relative content of alkoxy carbon is less. The relative content of alkoxy carbon in soil organic matter can be increased by wheat straw and corn straw returning, and the content and aromaticity of amides in SOM after returning to field of corn straw are higher than those in SOM after wheat straw returning to the field. The chemical structure of SOM and POM was affected by the degradation of wheat straw under different water management conditions. Under aerobic conditions, the relative content of alkoxy carbon in SOM, POM 500-53 mu m, POM 53 mu m was increased after the aerobic condition was returned to field, and the relative content of SOM, POM 500-53 Mu m, POM 53 Mu and alkyl carbon oxygen carbon in POM 53 Mu under anaerobic conditions Quantity.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S141.4

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