黄土丘陵区水蚀坡面土壤碳排放影响因素及模拟
发布时间：2019-02-13 09:11
【摘要】：土壤侵蚀是普遍存在的环境问题,由此引起的土壤有机碳迁移和再分布强烈影响碳循环过程和碳排放。当前关于侵蚀条件下土壤碳排放和控制机理认识还不统一,相关研究很少涉及土壤碳排放多因素综合影响及碳源汇关系转换条件,对于侵蚀影响下陆地生态系统碳源汇效应评估仍具有较大的不确定性。本研究以黄土丘陵区水蚀坡面为研究对象,通过野外采样测定、土壤呼吸监测以及室内矿化培养试验,利用相关分析、通径分析等方法,分析了土壤碳排放影响因素作用机制,通过模型模拟不同有机碳水平下侵蚀坡面碳排放多因素综合影响,对水蚀坡面土壤碳源汇转换临界条件进行探讨。主要结论如下:1)本研究区侵蚀坡面土壤呼吸速率影响因素的主次关系为:土壤温度土壤含水量土壤有机碳水平坡位,温度是影响该区土壤呼吸速率的最主要因素。土壤温湿度主要通过对土壤呼吸的直接作用对土壤呼吸速率产生影响,通径系数分别为0.619和0.257。土壤有机碳含量与土壤呼吸速率密切相关,0.5 mm土壤团聚体含量和容重的间接作用主要通过土壤有机碳对土壤呼吸产生影响,间接通径系数分别为0.292和-0.158。2)不同有机碳背景下水蚀坡面表现出不同的有机碳矿化特征。在侵蚀区,坡面侵蚀加速了土壤有机碳矿化;在沉积区,低碳(C1)水平下坡面侵蚀促进了土壤有机碳矿化,中碳(C3)和高碳(C4)水平下土壤有机碳矿化受到抑制。3)土壤有机碳水平、温度和含水量对土壤有机碳矿化潜力(Cp值)有明显影响,土壤温湿度的影响随有机碳水平的降低而减小。Cp值能综合反映土壤有机碳水平、温度和含水量对有机碳矿化的影响,可以用来解释土壤有机碳矿化影响因素的作用机理。在一级动力学方程的基础上,通过Cp值修正,得到土壤有机碳矿化多因素方程,可以很好地拟合不同有机碳水平下土壤有机碳矿化动态。4)土壤温湿度双因素模型对水蚀坡面土壤呼吸速率的拟合度较好(0.385R20.709),在C0水平下,其决定系数R2较大(0.612-0.709),土壤呼吸速率对土壤温湿度的变化较为敏感。在土壤温湿度双因素模型的基础上,得到土壤呼吸速率多因素方程,可以很好地拟合不同有机碳水平下土壤呼吸速率(0.457R20.573)。不同有机碳水平下的沉积区和侵蚀区的源汇转换条件有较大差异。在沉积区,土壤有机碳水平越高,土壤源汇临界温湿度越高,沉积区土壤碳源汇功能变化与土壤有机碳水平密切相关;在侵蚀区,临界温湿度未表现出明显的随有机碳水平的变化规律。
[Abstract]:Soil erosion is a common environmental problem. The migration and redistribution of soil organic carbon strongly affect the process of carbon cycle and carbon emissions. At present, the understanding of soil carbon emission and control mechanism under erosion conditions is not uniform, and few related studies are related to the comprehensive effects of soil carbon emissions and the conversion conditions of carbon sources and sinks. There is still considerable uncertainty about the assessment of carbon sink effects in terrestrial ecosystems under erosion. In this study, the mechanism of influencing factors of soil carbon emission was analyzed through field sampling, soil respiration monitoring and indoor mineralized culture test, correlation analysis, path analysis and so on. The critical conditions of carbon sink conversion in soil on eroded slope were studied by simulating the influence of multiple factors on carbon emission from erosion slope under different organic carbon levels. The main conclusions are as follows: 1) the main and secondary relationships of soil respiration rate on erosion slope in this study area are as follows: soil temperature soil moisture content soil organic carbon level slope position temperature is the most important factor affecting soil respiration rate. Soil temperature and humidity mainly affect soil respiration rate through direct action on soil respiration. The path coefficient is 0.619 and 0.257 respectively. Soil organic carbon content was closely related to soil respiration rate. The indirect effect of soil aggregate content and bulk density on soil respiration was mainly through soil organic carbon. The indirect path coefficients are 0.292 and -0.158.2 respectively) the slope surface of water erosion shows different characteristics of organic carbon mineralization under different organic carbon background. In the erosion area, slope erosion accelerates the mineralization of soil organic carbon. In sedimentary area, slope erosion promoted soil organic carbon mineralization at low carbon (C1) level, while middle carbon (C 3) and high carbon (C 4) levels were inhibited. 3) soil organic carbon level. The effect of temperature and water content on soil organic carbon mineralization potential (Cp value) was obvious, and the effect of soil temperature and humidity decreased with the decrease of organic carbon level. Cp value could reflect soil organic carbon level comprehensively. The effect of temperature and water content on organic carbon mineralization can be used to explain the mechanism of soil organic carbon mineralization. Based on the first-order kinetic equation, the multi-factor equation of soil organic carbon mineralization was obtained by modifying the Cp value. Soil organic carbon mineralization dynamics can be fitted well under different organic carbon levels. 4) soil temperature and humidity double factor model has a good fit (0.385R20.709) for soil respiration rate on water erosion slope, and at C 0 level, soil respiration rate is better than that at C 0 level. The coefficient of determination R2 is larger (0.612-0.709), and the soil respiration rate is more sensitive to the change of soil temperature and humidity. Based on the two-factor model of soil temperature and humidity, the multi-factor equation of soil respiration rate can be obtained, which can fit soil respiration rate (0.457R20.573) well under different organic carbon levels. The source and sink conversion conditions of sedimentary and erosion areas are different under different organic carbon levels. In the sedimentary area, the higher the soil organic carbon level, the higher the critical temperature and humidity of the soil source and sink. The change of soil carbon sink function is closely related to the soil organic carbon level. In the erosion zone, the critical temperature and humidity did not show obvious change with the organic carbon level.
【学位授予单位】：中国科学院研究生院(教育部水土保持与生态环境研究中心)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S157;S154.1
本文编号：2421390
[Abstract]:Soil erosion is a common environmental problem. The migration and redistribution of soil organic carbon strongly affect the process of carbon cycle and carbon emissions. At present, the understanding of soil carbon emission and control mechanism under erosion conditions is not uniform, and few related studies are related to the comprehensive effects of soil carbon emissions and the conversion conditions of carbon sources and sinks. There is still considerable uncertainty about the assessment of carbon sink effects in terrestrial ecosystems under erosion. In this study, the mechanism of influencing factors of soil carbon emission was analyzed through field sampling, soil respiration monitoring and indoor mineralized culture test, correlation analysis, path analysis and so on. The critical conditions of carbon sink conversion in soil on eroded slope were studied by simulating the influence of multiple factors on carbon emission from erosion slope under different organic carbon levels. The main conclusions are as follows: 1) the main and secondary relationships of soil respiration rate on erosion slope in this study area are as follows: soil temperature soil moisture content soil organic carbon level slope position temperature is the most important factor affecting soil respiration rate. Soil temperature and humidity mainly affect soil respiration rate through direct action on soil respiration. The path coefficient is 0.619 and 0.257 respectively. Soil organic carbon content was closely related to soil respiration rate. The indirect effect of soil aggregate content and bulk density on soil respiration was mainly through soil organic carbon. The indirect path coefficients are 0.292 and -0.158.2 respectively) the slope surface of water erosion shows different characteristics of organic carbon mineralization under different organic carbon background. In the erosion area, slope erosion accelerates the mineralization of soil organic carbon. In sedimentary area, slope erosion promoted soil organic carbon mineralization at low carbon (C1) level, while middle carbon (C 3) and high carbon (C 4) levels were inhibited. 3) soil organic carbon level. The effect of temperature and water content on soil organic carbon mineralization potential (Cp value) was obvious, and the effect of soil temperature and humidity decreased with the decrease of organic carbon level. Cp value could reflect soil organic carbon level comprehensively. The effect of temperature and water content on organic carbon mineralization can be used to explain the mechanism of soil organic carbon mineralization. Based on the first-order kinetic equation, the multi-factor equation of soil organic carbon mineralization was obtained by modifying the Cp value. Soil organic carbon mineralization dynamics can be fitted well under different organic carbon levels. 4) soil temperature and humidity double factor model has a good fit (0.385R20.709) for soil respiration rate on water erosion slope, and at C 0 level, soil respiration rate is better than that at C 0 level. The coefficient of determination R2 is larger (0.612-0.709), and the soil respiration rate is more sensitive to the change of soil temperature and humidity. Based on the two-factor model of soil temperature and humidity, the multi-factor equation of soil respiration rate can be obtained, which can fit soil respiration rate (0.457R20.573) well under different organic carbon levels. The source and sink conversion conditions of sedimentary and erosion areas are different under different organic carbon levels. In the sedimentary area, the higher the soil organic carbon level, the higher the critical temperature and humidity of the soil source and sink. The change of soil carbon sink function is closely related to the soil organic carbon level. In the erosion zone, the critical temperature and humidity did not show obvious change with the organic carbon level.
【学位授予单位】：中国科学院研究生院(教育部水土保持与生态环境研究中心)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S157;S154.1
【参考文献】
相关期刊论文 前10条
1 魏守才;张晓平;陈学文;;土壤水蚀对土壤有机碳动态及全球碳循环平衡的影响[J];土壤与作物;2015年04期
2 王菁;陈防;刘毅;;不同粒级土壤团聚体呼吸特征及其对碳排放的贡献[J];植物科学学报;2014年06期
3 胡婵娟;刘国华;郭雷;刘宇;;土壤侵蚀对土壤理化性质及土壤微生物的影响[J];干旱区研究;2014年04期
4 王君;宋新山;严登华;陈燕;;多重干湿交替格局下土壤Birch效应的响应机制[J];中国农学通报;2013年27期
5 朱凌宇;潘剑君;张威;;祁连山不同海拔土壤有机碳库及分解特征研究[J];环境科学;2013年02期
6 汪张懿;宗良纲;褚慧;谢少华;杨旎;罗敏;;有机肥分解及其对土壤有机碳矿化影响的模拟研究[J];农业环境科学学报;2013年01期
7 裴会敏;许明祥;李强;脱登峰;;侵蚀条件下土壤有机碳流失研究进展[J];水土保持研究;2012年06期
8 杨倩;张清平;蒋海亮;杨德雄;王先之;沈禹颖;;保护性耕作对黄土旱塬玉米土壤呼吸及微生物数量的影响[J];草业科学;2012年12期
9 马昕昕;许明祥;杨凯;;黄土丘陵区刺槐林深层土壤有机碳矿化特征初探[J];环境科学;2012年11期
10 裴会敏;许明祥;脱登峰;;黄土丘陵区坡地侵蚀对土壤呼吸的影响[J];水土保持通报;2012年04期
相关硕士学位论文 前1条
1 贾红丽;黄河三角洲典型湿地表观土壤呼吸通量及有机碳矿化动态模拟[D];中国海洋大学;2014年
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