黃土丘陵區(qū)水蝕坡面土壤碳排放影響因素及模擬
發(fā)布時間：2019-02-13 09:11
【摘要】：土壤侵蝕是普遍存在的環(huán)境問題,由此引起的土壤有機碳遷移和再分布強烈影響碳循環(huán)過程和碳排放。當前關(guān)于侵蝕條件下土壤碳排放和控制機理認識還不統(tǒng)一,相關(guān)研究很少涉及土壤碳排放多因素綜合影響及碳源匯關(guān)系轉(zhuǎn)換條件,對于侵蝕影響下陸地生態(tài)系統(tǒng)碳源匯效應(yīng)評估仍具有較大的不確定性。本研究以黃土丘陵區(qū)水蝕坡面為研究對象,通過野外采樣測定、土壤呼吸監(jiān)測以及室內(nèi)礦化培養(yǎng)試驗,利用相關(guān)分析、通徑分析等方法,分析了土壤碳排放影響因素作用機制,通過模型模擬不同有機碳水平下侵蝕坡面碳排放多因素綜合影響,對水蝕坡面土壤碳源匯轉(zhuǎn)換臨界條件進行探討。主要結(jié)論如下:1)本研究區(qū)侵蝕坡面土壤呼吸速率影響因素的主次關(guān)系為:土壤溫度土壤含水量土壤有機碳水平坡位,溫度是影響該區(qū)土壤呼吸速率的最主要因素。土壤溫濕度主要通過對土壤呼吸的直接作用對土壤呼吸速率產(chǎn)生影響,通徑系數(shù)分別為0.619和0.257。土壤有機碳含量與土壤呼吸速率密切相關(guān),0.5 mm土壤團聚體含量和容重的間接作用主要通過土壤有機碳對土壤呼吸產(chǎn)生影響,間接通徑系數(shù)分別為0.292和-0.158。2)不同有機碳背景下水蝕坡面表現(xiàn)出不同的有機碳礦化特征。在侵蝕區(qū),坡面侵蝕加速了土壤有機碳礦化;在沉積區(qū),低碳(C1)水平下坡面侵蝕促進了土壤有機碳礦化,中碳(C3)和高碳(C4)水平下土壤有機碳礦化受到抑制。3)土壤有機碳水平、溫度和含水量對土壤有機碳礦化潛力(Cp值)有明顯影響,土壤溫濕度的影響隨有機碳水平的降低而減小。Cp值能綜合反映土壤有機碳水平、溫度和含水量對有機碳礦化的影響,可以用來解釋土壤有機碳礦化影響因素的作用機理。在一級動力學(xué)方程的基礎(chǔ)上,通過Cp值修正,得到土壤有機碳礦化多因素方程,可以很好地擬合不同有機碳水平下土壤有機碳礦化動態(tài)。4)土壤溫濕度雙因素模型對水蝕坡面土壤呼吸速率的擬合度較好(0.385R20.709),在C0水平下,其決定系數(shù)R2較大(0.612-0.709),土壤呼吸速率對土壤溫濕度的變化較為敏感。在土壤溫濕度雙因素模型的基礎(chǔ)上,得到土壤呼吸速率多因素方程,可以很好地擬合不同有機碳水平下土壤呼吸速率(0.457R20.573)。不同有機碳水平下的沉積區(qū)和侵蝕區(qū)的源匯轉(zhuǎn)換條件有較大差異。在沉積區(qū),土壤有機碳水平越高,土壤源匯臨界溫濕度越高,沉積區(qū)土壤碳源匯功能變化與土壤有機碳水平密切相關(guān);在侵蝕區(qū),臨界溫濕度未表現(xiàn)出明顯的隨有機碳水平的變化規(guī)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.
【學(xué)位授予單位】：中國科學(xué)院研究生院(教育部水土保持與生態(tài)環(huán)境研究中心)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：S157;S154.1
本文編號：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.
【學(xué)位授予單位】：中國科學(xué)院研究生院(教育部水土保持與生態(tài)環(huán)境研究中心)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：S157;S154.1
【參考文獻】
相關(guān)期刊論文 前10條
1 魏守才;張曉平;陳學(xué)文;;土壤水蝕對土壤有機碳動態(tài)及全球碳循環(huán)平衡的影響[J];土壤與作物;2015年04期
2 王菁;陳防;劉毅;;不同粒級土壤團聚體呼吸特征及其對碳排放的貢獻[J];植物科學(xué)學(xué)報;2014年06期
3 胡嬋娟;劉國華;郭雷;劉宇;;土壤侵蝕對土壤理化性質(zhì)及土壤微生物的影響[J];干旱區(qū)研究;2014年04期
4 王君;宋新山;嚴登華;陳燕;;多重干濕交替格局下土壤Birch效應(yīng)的響應(yīng)機制[J];中國農(nóng)學(xué)通報;2013年27期
5 朱凌宇;潘劍君;張威;;祁連山不同海拔土壤有機碳庫及分解特征研究[J];環(huán)境科學(xué);2013年02期
6 汪張懿;宗良綱;褚慧;謝少華;楊旎;羅敏;;有機肥分解及其對土壤有機碳礦化影響的模擬研究[J];農(nóng)業(yè)環(huán)境科學(xué)學(xué)報;2013年01期
7 裴會敏;許明祥;李強;脫登峰;;侵蝕條件下土壤有機碳流失研究進展[J];水土保持研究;2012年06期
8 楊倩;張清平;蔣海亮;楊德雄;王先之;沈禹穎;;保護性耕作對黃土旱塬玉米土壤呼吸及微生物數(shù)量的影響[J];草業(yè)科學(xué);2012年12期
9 馬昕昕;許明祥;楊凱;;黃土丘陵區(qū)刺槐林深層土壤有機碳礦化特征初探[J];環(huán)境科學(xué);2012年11期
10 裴會敏;許明祥;脫登峰;;黃土丘陵區(qū)坡地侵蝕對土壤呼吸的影響[J];水土保持通報;2012年04期
相關(guān)碩士學(xué)位論文 前1條
1 賈紅麗;黃河三角洲典型濕地表觀土壤呼吸通量及有機碳礦化動態(tài)模擬[D];中國海洋大學(xué);2014年
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