赤峰市敖汉旗农田土壤有机碳库变化特征及其固碳潜力研究

发布时间：2018-03-02 06:32

本文关键词： 农田土壤有机碳变化影响因素固碳潜力　出处：《内蒙古农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：土壤有机碳(SOC)含量对维持和提高土壤肥力具有重要作用。本文以内蒙古赤峰市敖汉旗农田土壤为研究对象,通过实地采样并采用相关性、差异性、通径分析、CCA排序分析方法,探讨不同农田下的土壤有机碳垂直变化状况,研究地形因子、土壤理化性质及农田管理措施的差异对农田土壤有机碳的影响,且针对该旗农田土壤碳固定潜力状况进行研究,为合理管理和提高敖汉旗农田土壤碳库提供科学参考和基础数据。主要得出以下结论:1.敖汉旗农田土壤有机碳含量频率呈现正态分布,土壤有机质的均值约为9.07g/kg,处于缺乏状态。有机碳密度的均值为1.66kg/m2,大多处于1.15～2.15kg/m2之间,数据较离散,表明该旗农田土壤有机碳密度分布具有不均衡性。土壤有机碳含量均随土层深度的加深而降低,有明显表聚特点。各土壤类型的不同深度土壤中,土壤有机碳密度均表现为底层最高,底层受长年耕作压实作用大。在土壤60cm深度范围内,有机碳含量和密度最大、最小的土壤类型均分别为:棕壤土、风沙土,水浇地有机碳含量和密度均多于旱地。棕壤农田和水浇地规模的扩大有利于农田SOC的累积。2.各层土壤有机碳含量均随海拔、坡度的增加,呈现先增加后降低的趋势,阴坡的农田土壤有机碳含量显著高于阳坡(P0.05)。农田地形、土壤理化性质、管理措施对SOC含量的影响由大到小分别表现为:海拔坡度坡向,粘粒含水量容重全氮砂粒速效钾,秸秆还田传统耕作覆膜。通过CCA综合性排序分析可知,各主要影响因素中影响有机碳含量大小的排序为:农田管理措施土壤含水量粘粒含量容重海拔坡度。可通过免耕、秸秆还田等措施以提高农田土壤肥力。3.棕壤土耕层固碳潜力较强。农田耕层和60cm深度范围内土壤现有总SOC储量分别为2.77×106t、8.4×106t。农田土壤退耕还林后,耕层和60cm层土壤理想固碳潜力分别为2.70×106t、3.21×106t。考虑到当地人口粮食需求的情况下,可以退耕的农田面积为1216.5km2,现实固碳潜力分别为2.09×106t、2.46×106t。
[Abstract]:Soil organic carbon (SOC) content plays an important role in maintaining and improving soil fertility. In this paper, the farmland soil in Aohan Banner, Chifeng City, Inner Mongolia is taken as the research object. The method of CCA sorting analysis is adopted through field sampling and correlation, difference and path analysis. The vertical variation of soil organic carbon under different farmland was studied, and the effects of topographic factors, soil physicochemical properties and farmland management measures on soil organic carbon were studied, and the potential of soil carbon fixation in this flag was also studied. To provide scientific reference and basic data for rational management and improvement of soil carbon pool in Aohan Banner, the main conclusions are as follows: 1. The frequency of soil organic carbon content in Aohan Banner presents normal distribution. The average value of soil organic matter is about 9.07 g / kg, and the average value of organic carbon density is 1.66 kg / m ~ (2), mostly between 1.15 kg / m ~ (2) and 2.15 kg / m ~ (2). The results showed that the distribution of soil organic carbon density was uneven, and the content of soil organic carbon decreased with the deepening of soil depth. The soil organic carbon density was the highest in the bottom layer, and the organic carbon content and density were the highest in the depth of 60 cm, and the lowest soil types were brown soil and aeolian sandy soil, respectively, in the range of 60cm soil depth, the soil organic carbon density was the highest in the bottom layer, and the soil bottom was compacted by cultivation for a long time. The content and density of organic carbon in irrigated land were higher than those in dryland. The increase of soil organic carbon content in brown soil and irrigated land was beneficial to the accumulation of SOC in farmland. The soil organic carbon content in all layers increased first and then decreased with the increase of elevation and slope. Soil organic carbon content in shady slope was significantly higher than that in sunny slope P0.05.The effects of farmland topography, soil physical and chemical properties and management measures on SOC content were as follows: slope direction of elevation, soil water content, bulk density, available K of total nitrogen sand. According to the comprehensive sequencing analysis of CCA, the order of the main influencing factors on organic carbon content is: soil water content, soil moisture content, bulk density, elevation slope, soil water content, soil moisture content, bulk density, soil water content, soil moisture content, soil moisture content, bulk density, soil water content, The total SOC reserves of cultivated layer and 60 cm depth of farmland were 2.77 脳 10 ~ 6t ~ 8.4 脳 10 ~ (6) t, respectively. After returning farmland to forest, the total SOC reserves of cultivated layer in brown soil were 2.77 脳 10 ~ (6) t ~ (-1) ~ 8.4 脳 10 ~ (-6) t, respectively. The ideal carbon sequestration potential of plough layer and 60cm layer is 2.70 脳 10 ~ (6) t ~ (-1) ~ 3.21 脳 10 ~ (6) t ~ (-1) respectively. Considering the food demand of local population, the farmland area that can be returned to farmland is 1216.5 km ~ (2), and the actual carbon sequestration potential is 2.09 脳 10 ~ (6) t ~ (-1) ~ 2.46 脳 10 ~ (6) t.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S153.6

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