本文選題：土壤有機碳 + 礦化　； 參考：《西南大學》2015年碩士論文

【摘要】：采用野外采樣和室內(nèi)培養(yǎng)試驗,研究了不同土地利用類型(林地和旱地)下的石灰土和黃壤(旱地)表層土壤有機碳(SOC)礦化對溫度變化的響應(yīng)。三種供試土樣分別采自貴州省普定縣天龍山區(qū)域的典型林地和旱地的0～10cm表層。針對3種供試土壤,設(shè)置2種溫度培養(yǎng)模式：①恒溫模式,包括25℃、20℃、15℃,分別簡稱為HT-25、HT-20、HT-15;②變溫處理,范圍：15℃～25℃,變溫間隔12h,每24h為1個周期,簡稱為BT-15/25,其中變溫處理和20℃恒溫處理的積溫相同,培養(yǎng)時間為56d。利用培養(yǎng)過程中測得的相關(guān)數(shù)據(jù),系統(tǒng)研究溫度變化對土壤有機碳礦化及其動力學特征的影響,為全面認識土壤有機碳礦化的溫度效應(yīng)以及有機碳礦化模型的構(gòu)建提供基礎(chǔ)資料和科學參考。研究結(jié)果如下：(一)相同培養(yǎng)溫度條件下,3種土壤相同培養(yǎng)時間段內(nèi)的日均礦化量和累積礦化量大小順序為：森林石灰土旱地石灰土黃壤,且差異均達到顯著性水平(P0.05)。不同培養(yǎng)溫度條件下,3種土壤前14d的有機碳平均礦化速率顯著高于其后42d的礦化速率,培養(yǎng)前14d釋放的CO2量約占總礦化量的60%～68%,這表明前14d的礦化速率決定了整個培養(yǎng)期內(nèi)的有機碳累積礦化量。恒溫培養(yǎng)條件下,3種土壤的累積礦化量和礦化強度隨著培養(yǎng)溫度的升高而顯著增加。森林石灰土BT-15/25處理的有機碳累積礦化量和礦化強度顯著低于HT-20處理,黃壤BT-15/25處理的有機碳累積礦化量和礦化強度則顯著高于HT-20處理,旱地石灰土2種溫度處理之間的累積礦化量和礦化強度則無明顯差異,說明培養(yǎng)溫度模式(恒溫和變溫)的變化顯著影響土壤有機碳的礦化,通常利用恒溫培養(yǎng)下獲得的土壤礦化數(shù)據(jù)來預(yù)測和衡量田間土壤碳礦化水平的方法是有待商榷的,判定有機碳礦化對變溫環(huán)境的響應(yīng)程度是準確估算土壤CO2排放量的關(guān)鍵。(二)土壤有機碳累積礦化量與有機碳含量呈顯著或極顯著正相關(guān)(P0.05、P0.01),表明土壤有機碳含量是控制礦化過程的重要因素。3種土壤變溫處理的累積礦化量和礦化強度總是介于HT-25和HT-15處理之間,說明變溫處理的有機碳礦化受到溫度變化范圍的限制。受土地利用和植被類型的影響,森林石灰土和2種旱地土壤的表層有機碳含量和組成差異顯著,結(jié)合土壤有機碳含量和組成、Q10值和礦化強度之間的關(guān)系分析可知,有機碳含量和組成等自身屬性可能是影響其礦化過程對外界溫度變化響應(yīng)的重要原因。(三)森林石灰土變溫處理的潛在礦化量顯著低于HT-20處理,且C0/SOC明顯小于旱地石灰土和黃壤,說明變溫環(huán)境中森林石灰土微生物分解有機碳的能力減弱,微生物對碳源的利用效率降低。(四)培養(yǎng)過程中土壤的κs隨著溫度的升高而升高,這表明隨著溫度的升高土壤微生物利用難分解碳庫的能力逐漸增強。整個培養(yǎng)期內(nèi),3種土壤的難分解有機碳含量與累積礦化量的比值達到近40%,這顯示在有機碳礦化過程中難分解碳庫與易分解碳庫有著同等重要的作用。通過比較分析變溫處理和恒溫20℃處理條件下森林石灰土、旱地石灰土和黃壤有機碳礦化動力學方程中各參數(shù)的變化規(guī)律,發(fā)現(xiàn)變溫環(huán)境主要通過改變易分解碳庫的含量和難分解碳庫的礦化速率常數(shù)來影響土壤有機碳礦化過程。(五)整個培養(yǎng)期間,由于土壤可溶性有機碳的溶出量與有機碳含量的關(guān)聯(lián)性,有機碳含量較高的森林石灰土的可溶性有機碳含量始終高于旱地石灰土和黃壤。土壤類型和所處溫度條件的不同,使土壤可溶性有機碳的溶出量亦有差異,這主要與土壤有機碳的溫度敏感性和不同溫度條件下土壤微生物群落活性有關(guān)。3種土壤不同溫度條件下的可溶性有機碳含量與有機碳日均礦化量均呈極顯著正相關(guān),表明制約土壤可溶性有機碳生成是溫度影響有機碳礦化的一個重要途徑。(六)由于土壤微生物量碳與土壤有機碳含量的相關(guān)性,森林石灰土的微生物量碳含量顯著高于旱地石灰土和黃壤。除HT-25處理條件下黃壤的微生物量碳含量與日均礦化量顯著相關(guān)外,各處理的土壤微生物量碳含量與有機碳的日均礦化量均無顯著相關(guān)性；土壤微生物量碳也不能有效反映升溫過程中以及恒溫和變溫處理之間土壤有機碳礦化的差異,該現(xiàn)象表明,溫度條件不能通過顯著改變土壤微生物數(shù)量來影響有機碳礦化過程。溫度變化可能通過影響土壤微生物群落的組成、結(jié)構(gòu)和活性從而改變微生物利用有機碳的能力,進而對土壤有機碳礦化過程產(chǎn)生影響。結(jié)合礦化動力學分析可知,土壤微生物群落活性的變化是影響有機碳礦化的關(guān)鍵,溫度能通過改變土壤微生物群落的活性來影響有機碳礦化過程。
[Abstract]:The response of soil organic carbon (SOC) mineralization in calcareous soil and yellow soil (dryland) under different land use types (Woodland and dry land) to temperature changes under different land use types (Woodland and dry land) was studied by field sampling and indoor culture test. Three samples were collected from typical woodland and 0 ~ 10cm surface of dry land in Tianlong mountain area of Puding County, Guizhou province. 3 kinds of soil samples were provided. 2 temperature cultivation modes were set up in the test soil: (1) constant temperature mode, including 25, 20, 15 C, respectively for HT-25, HT-20, HT-15, and variable temperature treatment, range: 15 C to 25 C, variable temperature interval 12h, 1 cycles per 24h, which was called BT-15/25, in which the temperature treatment was the same as that of the constant temperature treatment at the same temperature, and the incubation time was 56d. utilization and culture process. The influence of temperature change on soil organic carbon mineralization and its dynamic characteristics is systematically studied in this paper, which provides basic information and scientific reference for a comprehensive understanding of the temperature effect of soil organic carbon mineralization and the construction of organic carbon mineralization model. The results are as follows: (1) 3 kinds of soil Xiang Tongpei under the same incubation temperature. The order of daily average mineralization and accumulated mineralization in the period of the cultivation period is: the forest calcareous lime soil yellow soil in the forest calcareous soil, and the difference reached significant level (P0.05). The average mineralization rate of the organic carbon in the 3 kinds of soil before the different culture temperatures is significantly higher than that of the subsequent 42d, and the CO2 amount released by the 14d before the culture is about the total ore. The mineralization rate of 14d was 60% ~ 68%. The cumulative mineralization of organic carbon in the whole culture period was determined by the mineralization rate of the whole culture period. The cumulative mineralization and mineralization intensity of the 3 soils increased significantly with the increase of incubation temperature. The cumulative mineralization and mineralization intensity of organic carbon in the forest calcareous soil BT-15/25 treatment was significantly lower than that of HT-2. 0 treatment, the cumulative mineralization and mineralization intensity of organic carbon in the yellow soil BT-15/25 treatment was significantly higher than that of HT-20 treatment. There was no significant difference in cumulative mineralization and mineralization intensity between 2 temperature treatments in dryland, indicating that the change of incubation temperature model (constant temperature and variable temperature) significantly affected the mineralization of soil organic carbon, usually using constant temperature culture. The method to predict and measure the soil carbon mineralization level in the field is debatable. The determination of the response degree of the organic carbon mineralization to the variable temperature environment is the key to the accurate estimation of soil CO2 emissions. (two) the cumulative mineralization of soil organic carbon has significant or extremely significant positive correlation with the organic carbon content (P0.05, P0.01). The content of organic carbon in soil is an important factor in controlling the mineralization process. The cumulative mineralization and mineralization intensity of.3 soil temperature treatment are always between HT-25 and HT-15 treatments. It shows that the mineralization of organic carbon in the variable temperature treatment is limited by the range of temperature change. There are significant differences in the content and composition of the surface organic carbon. According to the relationship between the soil organic carbon content and composition, the relationship between the Q10 value and the mineralization strength, it is found that the organic carbon content and composition may be the important reasons for the response of the mineralization process to the external temperature change. (three) the potential mineralization of the forest calcareous soil temperature change treatment is obvious. It was lower than HT-20 treatment, and C0/SOC was obviously less than calcareous soil and yellow soil in dry land, which indicated that the ability of microorganism to decompose organic carbon in forest calcareous soil decreased and the efficiency of microbial utilization of carbon source decreased. (four) the kappa s of soil increased with the increase of temperature during the process of culture, which indicated that the soil microorganism was used with the increase of temperature. The ability to decompose carbon pool is gradually enhanced. The ratio of the organic carbon content to the cumulative mineralization of the 3 soils in the whole culture period is nearly 40%, which shows that the decomposition of carbon pool and the decomposable carbon pool in the process of organic carbon mineralization has the same important role. By comparing and analyzing the forest stone under the temperature treatment and the constant temperature at 20 degrees C The variation of various parameters in the kinetic equation of mineral carbon mineralization in lime soil, dryland calcareous soil and yellow soil found that the temperature changing environment mainly influenced the mineralization process of soil organic carbon by changing the content of the decomposable carbon pool and the mineralization rate constant of the refractory carbon pool. (five) the dissolution of soil soluble organic carbon and the amount of soluble organic carbon in the whole culture period The soluble organic carbon content of forest calcareous soil with high organic carbon content is always higher than that of dryland calcareous soil and yellow soil. The difference of soil type and temperature conditions makes the soluble amount of soluble organic carbon dissolve in soil, which is mainly due to the temperature sensitivity of soil organic carbon and soil under different temperatures. The content of soluble organic carbon in different temperature conditions of.3 species was significantly correlated with the daily average mineralization of organic carbon, indicating that the restriction of soil soluble organic carbon formation was an important way for temperature to affect the mineralization of organic carbon. (six) the correlation between soil microbial biomass carbon and soil organic carbon content was related. The microbial biomass carbon content of forest calcareous soil was significantly higher than that of dryland calcareous soil and yellow soil. In addition to the HT-25 treatment, the microbial biomass carbon content was significantly correlated with the daily average mineralization, and there was no significant correlation between the soil microbial biomass carbon content and the daily average mineralization of organic carbon, and the soil microbial biomass carbon could not be effectively reversed. The difference in soil organic carbon mineralization between temperature and temperature treatment is shown, which indicates that temperature can not affect the mineralization process of organic carbon by significantly changing the amount of soil microorganism. The temperature change may change the organic carbon by influencing the composition, structure and activity of soil microbial community. The ability to affect the mineralization process of soil organic carbon, combined with the analysis of mineralization kinetics, the change of soil microbial community activity is the key to influence the mineralization of organic carbon, and the temperature can affect the mineralization process of organic carbon by changing the activity of soil microbial community.
【學位授予單位】：西南大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S153.6

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