施氮水平对风沙土和冲积土有机碳组成及化学稳定性的影响

发布时间：2018-02-27 09:35

本文关键词： 风沙土和冲积土土壤有机碳稳定性氮肥　出处：《吉林农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：土壤有机碳是土壤肥力的重要指标,其固定和储备受土壤有机碳的稳定性影响。土壤有机碳稳定性是由土壤本身特性与外在的环境因子相互作用决定的。氮元素与碳元素同为生态系统中最基本的两大生命要素,在自然界的循环过程中不仅各自对全球变暖做出重要贡献,而且两者的循环过程显著耦合,互相影响各自的作用和效果。因此对不同施氮水平下土壤有机碳稳定性的影响进行研究,具有重要的理论和实践意义。本论文以农田风沙土和冲积土为研究对象,采用大田试验和室内分析相结合的方法,对不同施氮处理风沙土和冲积土中有机碳总有机碳水溶性有机碳、微生物量碳以及腐殖质的组分及其光谱性质进行研究,从而进一步阐明不同施氮处理对风沙土和冲积土有机碳稳定性的影响,为土壤碳库储备及有机碳的调控制定有效措施,从而减少土壤中二氧化碳的排放,同时也为实际农业生产提供技术措施和理论依据。研究结果表明:长期施用不同量的氮肥对土壤有机碳有一定的影响,随着施用氮肥量的增加,土壤有机碳总量呈现出先增加后降低的趋势,在冲积土中,当氮肥用量为270kg/hm2时,土壤有机碳含量最高,而风沙土中当氮肥用量为240处kg/hm2时,土壤有机碳的含量最高;随着氮肥施入,土壤中易氧化有机碳的含量先增加后降低,冲积土中在N168处理时达到最大值为4.54g/kg,风沙土中易氧化有机碳含量最高的处理为N240达到了3.48g/kg。不同用量氮肥对土壤有机碳氧化稳定性有一定的影响。风沙土有机碳氧化稳定系数在0.43~0.57之间,N270处理氧化稳定系数最高位0.75,N168处理氧化稳定系数最低位0.43。在冲积土中土壤有机碳氧化稳定系数变化区间为0.29~0.66之间,在N270处理出现最大值0.66,N312处理出现最小值0.29,不同处理间差异显著(P㩳0.05)。不同施氮水平对水溶性有机碳和微生物量碳有一定影响,风沙土和冲积土均在在N240达到最大。这说明施氮水平对土壤中有机碳活性有影响,在一定范围内能增加有机碳的活性,但随着施氮量增加有机碳的活性降低,有机碳的氧化稳定性增强,有利于土壤有机碳的固定,氮肥用量过高又会使土壤有机碳的稳定性降低。不同用量氮肥处理对土壤腐殖质组成及光学性质有一定的影响。腐殖质中粗胡敏素(HM)含量,在风沙土和冲积土中随施氮量的增加变化不是很明显,但也有一定程度的增加;腐殖质(HE)含量测定结果同HM趋势相同,含量也有小幅度的增加;随着施氮量的增加,胡敏酸含量有小幅的增加。风沙土和冲积土在N240处理达到最高;富里酸有机碳含量随着施氮量的增加反而出现了下降,但都在高施氮量时出现了上升,说明施氮量对富里酸含量的相应机制不显著。在风沙土中,适量的施氮肥能使脂肪族化合物以及多糖类及固醇类物质含量增加;而在冲积土中施入氮肥反而使脂肪族化合物和多糖类以及固醇类物质减少。不同氮肥用量对土壤有机碳化学稳定性有一定的影响。不同处理间,经H2SO4水解的风沙土和冲积土N240处理的总可溶性组分含量最高,为2.72g/kg,冲积土较风沙土明显,HCl水解法获得的可溶性组分与H2SO4水解法获得的可溶性组分变化规律基本一致,但在总体上HCl水解法获得的总可溶性组分高于H2SO4水解法获得的总可溶性组分。土壤有机碳活性指数,随着氮肥用量的增加,表现出先降低的趋势。风沙土在N0处理有机碳活性指数最大,N270处理最小;冲积土在N240处理最大,N312处理最小。不同用量氮肥处理中,冲积土土壤有机碳难降解指数在N312处理最大,N240处理最小,风沙土中土壤有机碳难降解性指数在N270处理最大,N0处理最小。施用氮肥通过增加土壤活性有机碳含量来增加土壤有机碳的含量,合理的氮肥用量可以使土壤中难降解有机碳指数增加,提高有机碳的化学稳定性。因此可以通过合理施用氮肥调控土壤有机碳含量及其稳定性。
[Abstract]:Soil organic carbon is an important indicator of soil fertility, which affected the stability of fixation and reserve by soil organic carbon. Soil organic carbon stability by soil characteristics and external environmental factors. The nitrogen and carbon elements with two life the most basic elements of ecological system, in the cycle of nature not only to make an important contribution to their global warming, and the two cycle significant coupling, mutual influence and effect each other. So the research on the effects of different nitrogen levels on soil organic carbon stability, has important theoretical and practical significance. In this paper, the farmland of aeolian sandy soil and alluvial soil as the research object, method based on the field test and laboratory analysis, the different nitrogen treatments of aeolian sandy soil and alluvial soil organic carbon and total organic carbon? Water soluble organic carbon, microbial biomass carbon and Study on composition and spectral properties of humus, so as to further elucidate the effects of different nitrogen treatments on Aeolian Sandy Soil and alluvial soil organic carbon stability, formulate effective measures for the control of soil carbon reserves and organic carbon in the soil, thereby reducing carbon dioxide emissions, as well as the actual agricultural production to provide theoretical basis and technical measures. The results showed that long-term application of different amount of nitrogen fertilizer had some effects on soil organic carbon, with the increase of nitrogen fertilizer amount, soil total organic carbon showed a trend of decrease after the first increase, in the alluvial soil, when nitrogen fertilizer was 270kg/hm2, soil organic carbon content was the highest, and the wind sand when n at the dosage of 240 kg/hm2, the highest content of soil organic carbon; with nitrogen fertilizer, the content of soil labile organic carbon increased and then reduced, alluvial soil in N168 treatment to achieve the most The large value of 4.54g/kg, in sandy soil easily oxidized organic carbon content was the highest in N240 treatment reached 3.48g/kg. different nitrogen fertilizer has certain effects on the oxidation stability of soil organic carbon. Sandy soil organic carbon oxidation stability coefficient between 0.43~0.57, N270 oxidation stability coefficient of the high of 0.75, N168 0.43. in the low oxidation stability coefficient alluvial soil changes in soil organic carbon oxidation stability coefficient range is between 0.29~0.66, in the N270 maximum value of 0.66 N312, the minimum value of 0.29, there were significant differences between different treatments (P? 0.05). Different levels of nitrogen fertilizer on the water has a certain effect of organic carbon and microbial biomass carbon, sandy soil and alluvial soil in the N240 reached the maximum. This shows that the nitrogen level had influence on the activity of soil organic carbon, organic carbon increased activity in a certain range, but with the increase of nitrogen organic carbon activity Reduce, enhance the oxidation stability of organic carbon, is conducive to soil organic carbon fixation, excessive nitrogen fertilizer will make the stability of soil organic carbon decreased. Different amount of nitrogen fertilizer had a certain influence on the composition and optical properties of soil humus. Hu Minsu crude humus (HM) content in aeolian sandy soil and alluvial soil with fertilizer the increase of nitrogen is not obvious changes, but also increased to a certain extent; humus (HE) determination results with HM the same trend, content is also a small increase; with the increase of nitrogen, increase Hu Min acid content with small amplitude. The aeolian sandy soil and alluvial soil treatment reached the highest in N240; fulvic acid organic carbon content with the increase of nitrogen fell, but in high nitrogen when rising, indicating the amount of nitrogen on the corresponding mechanism of fulvic acid was not significant. In the sandy soil, suitable amount of nitrogen fertilizer can make The increase of aliphatic compounds and polysaccharides and steroids content; while in alluvial soil nitrogen fertilizer instead of aliphatic compounds and polysaccharides, steroids reduce. Nitrogen fertilizer had a certain influence on the stability of soil organic carbon chemistry. Among the different treatments, the wind sand soil and alluvial soil total soluble N240 treatment group H2SO4 the hydrolysis of 2.72g/kg, the highest content was significantly higher than alluvial soil sandy soil, soluble group group HCl soluble hydrolysis and hydrolysis of H2SO4 to obtain the variation of basically the same, but the total soluble group HCl hydrolysis in the whole of the total soluble group was higher than that of H2SO4 hydrolysis obtained. Soil organic carbon activity index, with the increase of amount of nitrogen, shows a decreasing trend. Soil organic carbon activity in the N0 index is the largest, the lowest in N270 treatment; alluvial soil in N240 at most Large, N312 treatment is the lowest. Different amount of nitrogen fertilizer, soil organic carbon alluvial refractory index in N312 treatment, N240 treatment is the lowest in sandy soil, soil organic carbon refractory index in N270 treatment, N0 treatment is the lowest. Nitrogen fertilizer by increasing the activity of soil organic carbon content to increase the content of soil organic carbon the reasonable amount of nitrogen fertilizer can make soil refractory organic carbon index increase, improve the chemical stability of organic carbon. Therefore the soil organic carbon content regulation of reasonable application of nitrogen fertilizer and its stability.

【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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