湖北省主要水稻产区水稻土硝化、反硝化潜势及其与铁、锰的关系

发布时间：2018-05-31 20:00

本文选题：水稻土 + 硝化潜势　；参考：《华中农业大学》2017年硕士论文

【摘要】：农业土壤硝化、反硝化过程引起的氮素损失和温室气体N2O排放问题是学者们一直以来关注的热点。铁、锰作为土壤中性质极为活泼的变价元素,在稻田土壤中复杂的氧化还原条件变动的情况下,以得失电子的形式参与到土壤氮转化过程,使之与N2O排放的关系成为生物地球化学循环研究的热点之一。本研究通过对湖北省主要水稻产区的24个不同水稻土样本(咸宁市4个土样:X1、X2、X3、X4,武汉市东西湖区4个土样:W1、W2、W3、W4,天门市2个土样:T1、T2,枝江市1个土样:Z,鄂州市5个土样:E1、E2、E3、E4、E5,潜江市5个土样:Q1、Q2、Q3、Q4、Q5,华中农业大学校园试验场3个土样:H1、H2、H3)进行了硝化潜势、反硝化潜势的研究,分析了不同土样间硝化、反硝化潜势的差异,并探讨了土壤硝化、反硝化潜势与土壤铁锰含量及其他影响因子(土壤pH值、质地、可溶性有机碳、有机质、全氮、无机氮含量)的耦合关系。该研究有利于深入认识土壤氮转化机理,揭示铁锰含量及形态对土壤氮素循环的影响,为研究提高长江中下游平原稻田土壤氮素利用率提供理论基础。该研究得出主要结论如下:(1)供试土样间的硝化潜势存在极显著性差异(p0.001),24个土壤样品净硝化速率变化范围为0.11~17.22 mg N kg-1 d-1。供试土壤中,pH值较高、质地较轻的土样(T1、T2、Q1、Q2、Q3、Q4、Q5)硝化潜势较高一些,而pH值相对较低的土样(X2、X3、X4、E3、E4、E5、H1),其硝化潜势比较低。但部分(W2、W3、W4)土样即使其pH值均在7以下,硝化潜势却也较高。(2)土壤硝化潜势与土壤中无定形铁含量呈显著正相关关系(p0.05),无定形铁含量高有利于土壤硝化作用的进行。在pH值小于6.5的土壤中,无定形铁含量对硝化潜势有显著影响(p0.01),在pH值大于6.5的土壤中无定形铁含量对硝化潜势的影响不显著。在质地黏重、无定形铁含量高的土壤中,能加速硝化过程的进行,促使NH4+-N转化为NO3--N。(3)供试土样间的反硝化潜势存在一定差异,24个土壤样品中反硝化潜势变化范围为0.13 mg N kg-1 h-1~0.97 mg N kg-1 h-1。土壤有机质含量较高的土样(X2、W2、W3、E3)反硝化潜势更高一些,而有机质含量较低的水稻土(T2、H1、H2),其反硝化潜势也比较低。(4)土壤中络合铁和无定形铁的含量对反硝化潜势有显著影响,而锰的含量与反硝化潜势之间关系不显著。在仅考虑铁锰对反硝化潜势影响的前提下,络合铁和无定形铁含量是影响反硝化潜势的最主要的因子(n=24,p0.01,R2=0.454)。
[Abstract]:The nitrogen loss caused by agricultural soil nitrification and denitrification and the emission of greenhouse gas N _ 2O have been a hot topic for many scholars. Iron and manganese, as the most active variable value elements in soil, participate in the process of soil nitrogen transformation in the form of gain and loss electrons when the complex redox conditions change in paddy soil. The relationship between N2O emission and biogeochemical cycle has become one of the hotspots in biogeochemical cycle research. In this study, 24 different paddy soil samples from the main rice producing areas of Hubei Province (4 soil samples in Xianning City, 4 in X1, X2, X3, X4, 4 in Dongxihu District, Wuhan City, 4 in the Dongxi Lake District, Wuhan City, 2 soil samples in Tianmen City, 2 in T1 / T2, 1 in Zhijiang City, 1 in ZZ, 5 in Ezhou City, 5 in E1E1, E2, E3, E3, E5, respectively) were studied in this paper. The nitrification potential of 5 soil samples of Qianjiang City, 5: Q1Q2Q2Q3Q4Q5 and 3 samples of WH1H1H2H2H3), has been carried out in the campus test site of Huazhong Agricultural University. The difference of nitrification and denitrification potential among different soil samples was analyzed, and the soil nitrification, denitrification potential, soil iron and manganese content and other influencing factors (soil pH value, texture, soluble organic carbon, organic matter, soil pH value, texture, soluble organic carbon, organic matter) were discussed. The coupling relationship between total nitrogen and inorganic nitrogen content. This study is helpful to understand the mechanism of soil nitrogen transformation, to reveal the effect of iron and manganese content and form on soil nitrogen cycling, and to provide a theoretical basis for the study of improving soil nitrogen utilization efficiency in paddy fields in the middle and lower reaches of the Yangtze River. The main conclusions of the study were as follows: (1) the nitrification potential of the soil samples was significantly different, and the change range of the net nitrification rate of 24 soil samples was 0.11 ~ 17.22 mg N kg-1 路d ~ (-1). The nitrification potential of the soil samples with higher pH value and lighter soil texture was higher than that of the soil samples with lower pH value. The nitrification potential of the soil samples with relatively low pH value was lower than that of the soil samples with lower pH value. The nitrification potential of the soil samples with lower pH value was higher than that of the soil samples with lower pH value. The nitrification potential of the soil samples with a relatively low pH value was higher than that of the soil samples with a lighter texture. The nitrification potential of the samples was lower than that of the soil samples with lower pH value. However, the nitrification potential of some soil samples was higher even if the pH value was below 7.) the nitrification potential of the soil was significantly positively correlated with the content of amorphous iron in the soil, and the high content of amorphous iron was beneficial to the nitrification of the soil. In soil with pH < 6.5, amorphous iron content had a significant effect on nitrification potential, while in soil with pH > 6.5, the effect of amorphous iron content on nitrification potential was not significant. The nitrification process can be accelerated in soils with high amorphous iron content and viscous texture. The denitrification potential of 24 soil samples varied from 0.13 mg N kg-1 h-1 to 0.97 mg N kg-1 h-1. The denitrification potential of soil samples with higher organic matter content was higher, while the denitrification potential of rice soil with low organic matter content was also lower. (4) the contents of complex iron and amorphous iron had a significant effect on denitrification potential. However, the relationship between manganese content and denitrification potential was not significant. On the premise of considering the effect of iron and manganese on denitrification potential, the content of complex iron and amorphous iron is the most important factor affecting denitrification potential.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S153

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