發(fā)布時(shí)間：2018-03-10 03:14

  本文選題：土壤有機(jī)碳　切入點(diǎn)：土壤無(wú)機(jī)碳　出處：《新疆大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：探討干旱區(qū)土壤-植被生態(tài)系統(tǒng)碳來(lái)源與轉(zhuǎn)化是干旱區(qū)碳循環(huán)研究的一個(gè)重要領(lǐng)域,該研究可進(jìn)一步為干旱區(qū)碳資源的合理管理和保護(hù)提供參考。本研究以亞洲中部干旱區(qū)準(zhǔn)噶爾盆地南緣荒漠區(qū)為研究區(qū),根據(jù)荒漠距離綠洲的遠(yuǎn)近,分別在荒漠的邊緣(距離綠洲約5 km)、荒漠中部(距離綠洲約45 km)和荒漠腹地(距離綠洲約70 km)設(shè)置三條樣帶,并采集200cm深的土壤剖面樣品,研究土壤有機(jī)碳(SOC)、土壤無(wú)機(jī)碳(SIC)含量及其穩(wěn)定碳同位素的分布,探討土壤碳變化與距離綠洲遠(yuǎn)近的關(guān)系,探討土壤碳及其同位素分布規(guī)律。研究表明,SOC含量隨深度加深而減少,受距離綠洲遠(yuǎn)近的影響,SOC均值含量為荒漠邊緣荒漠中部荒漠腹地。SOC的δ~(13)C值范圍為-25.199‰~-17.418‰,隨深度變化先增后減,80cm左右富集,由此推斷準(zhǔn)噶爾盆地南緣荒漠區(qū)地表植被以C3植物為主,但綠洲邊緣又經(jīng)歷了從C3植物為主到C4植物為主的演替過(guò)程。受碳酸鹽淀積作用影響,80%的采樣點(diǎn)SIC累積量隨深度加深而先變大后變小,80cm左右富集;SIC的δ~(13)C值隨深度變化先變小后變大,底層富集,主要受原生碳酸鹽含量和剖面土壤CO2的影響。土壤C同位素變化對(duì)植被演替過(guò)程和成土程度的強(qiáng)弱有一定的指示意義。利用克里金插值對(duì)研究區(qū)采樣點(diǎn)各個(gè)深度有機(jī)碳同位素和無(wú)機(jī)碳同位素進(jìn)行空間分析,探討研究區(qū)碳及其同位素空間分布特征,找出其變化規(guī)律,這對(duì)其未來(lái)的變化趨勢(shì)有一定的預(yù)測(cè)作用。研究表明在0~20cm土壤有機(jī)碳δ~(13)C值整體的空間分布大體呈西南高,東南低,變化相對(duì)較緩和。有機(jī)碳δ~(13)C值的較低值對(duì)應(yīng)的面積比例逐漸增大即有機(jī)碳δ~(13)C值較低值所占面積百分比逐漸增大。在中部30~80cm范圍內(nèi)的有機(jī)碳δ~(13)C值變化較大,最大值重心也在不斷的遷移,從最開始的西南遷移到西北地區(qū),又遷移到東南地區(qū),上下層變化差異較大,空間分布相對(duì)不穩(wěn)定。80~200cm有機(jī)碳δ~(13)C值變化幅度最大,有機(jī)碳δ~(13)C值含量大體呈東北和東南區(qū)高,同時(shí)隨著深度的加深,最大值向中部靠近并有向西蔓延的趨勢(shì),低值區(qū)面積相對(duì)較大。研究表明在0~20cm整體的空間分布與表層空間分布相似,無(wú)機(jī)碳δ~(13)C值含量大體呈西部高,東部低,但均值比表層大,變化相對(duì)較緩和,較低值對(duì)應(yīng)的面積比例逐漸增大即無(wú)機(jī)碳δ~(13)C值較低值所占面積百分比逐漸增大。30~80cm范圍內(nèi)的無(wú)機(jī)碳δ~(13)C值變化較大,最大值重心也在不斷的遷移,且面積不斷增大,低值區(qū)不斷向東南角蔓延,面積越變?cè)叫?僅占所有面積的5%,與有機(jī)碳δ~(13)C值分布趨勢(shì)相反。80~200cm無(wú)機(jī)碳δ~(13)C值變化幅度較小,含量大體呈西南區(qū)高。
[Abstract]:The study of carbon source and transformation of soil-vegetation ecosystem in arid region is an important field in the study of carbon cycle in arid region. This study can be used as a reference for the rational management and protection of carbon resources in arid areas. In this study, the desert area of the southern margin of Junggar Basin in central Asia is taken as the study area, according to the distance from the desert to the oasis. Three samples were set up at the edge of the desert (about 5 km / m from the oasis), the middle part of the desert (about 45 km / m from the oasis) and the desert hinterland (about 70 km / m from the oasis), and the soil profile samples were collected at a depth of 200cm. The contents of soil organic carbon (SOC), inorganic carbon (sic) and the distribution of stable carbon isotopes were studied. The relationship between soil carbon change and the distance from oasis was discussed, and the distribution of soil carbon and its isotopes was also discussed. The results showed that the content of SOC decreased with the deepening of soil depth. Under the influence of the distance from oasis, the average content of SOC in the desert hinterland of desert center of desert margin was -25.199 鈥，

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