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Accumulation And Maintenance Of Soil Organic Carbon And Fragments In Different Successional Series Of Broadleaved Korean Pin Forests In The Temperate Zone In China

Posted on:2019-05-13Degree:DoctorType:Dissertation
Country:ChinaCandidate:L ZhangFull Text:PDF
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The soil carbon balance in forest ecosystems plays an irreplaceable role in the global carbon cycle.It not only maintains a stock of vegetation carbon,but also maintains a huge soil carbon pool,which is an important part of the global carbon cycle.Forest succession plays a very important role in the process of carbon sequestration in forest ecosystems.The research on the mechanism of soil organic carbon changes during forest succession is sporadic and scattered.There is still no accepted framework to explain the factors affecting the SOC accumulation during forest succession.The research results have not yet formed a unified and complete theoretical system..Most studies focus on a single soil type or location,and direct studies of soil carbon pools during community succession are very limited.It is necessary to further study the characteristics of soil organic carbon pools across the entire ecosystem and succession stages within different ecosystems,and determine the factors controlling these changes.Quantitative analysis of the natural processes of organic carbon accumulation and maintenance mechanisms in different successional series,revealing the accumulation and regulation of various components of soil organic carbon pools by forest succession changes,and accurately assessing the carbon cycle of forest ecosystems in temperate broad-leaved Korean pine forests.The source-sink function is extremely crucial,and it is also of great significance for effective management of soil carbon,scientific evaluation of the dynamic trend of soil carbon pools,and their function and status in the global carbon cycle.In this study,space was used the chronosequence methods(space-for-time substitution aqqroach)to select different succession series of broad-leaved Korean pine forests in the Xiaoxing'an mountains of Liangshui National Nature Reserve,including the mesosere series,hydrosere series,and xerosere series.The six typical community types in the succession series represent the different stages of the secondary succession series of broad-leaved Korean pine forests(the climax stage and secondary stage).1.The soil bulk density of the three successional series showed top community>secondary community(P<0.05);the soil moisture content was significantly different on the whole(P<0.01);the soil sand/grain ratio was significantly different(P<0.05),The porosity of soil capillary porosity is extremely significant,and the soil porosity of the same succession series is expressed as the top community<secondary community.The total phosphorus content in the soil was significantly different between mesosere series,hydrosere series,and xerosere series.The total potassium content in the soil was significantly different between the mesoseres successional succession series and the hydroseres and the xeroseres.2.The soil total organic carbon accumulation were 32.26±3.13g/kg-40.90±1.93g/kg,which was characterized by hydrosere succession series>mesosere succession series>xerosere succession series.The accumulation of soil organic carbon in the succession process of the middle-successive succession series community to the secondary community showed a downward trend;the wet succession series had been an upward trend;the drought-producing succession series had been a downward trend.The correlations between soil organic carbon accumulation and soil physical and chemical properties in different successional series were relatively large,among them,the correlation with soil total nitrogen and total phosphorus content is the largest,indicating that succession has a certain influence on the physical and chemical properties of soil,and community succession could change the status of soil nutrients.3.The soils mineralizable carbons which the xerosere succession series(413.48±77.87g/kg)were greater than hydrosere succession series(410.65±49.52g/kg)and mesosere succession series(345.56±88.61g/kg).The total soil mineralizable carbon accumulation was generally expressed as climax community more than secondary community.The mineralization carbon mineralization rates showed the same trend with time,ie,the rapid decline in the early culture and the gradual stabilization in the later period.Soils with different succession series of broadleaved-Korean pine forests were affected by soil water content,biomass of forest litter and soil total nitrogen content,soil bulk density,pH value,sand-grain ratio.4.The soil easily-oxidizable organic carbon gradually decreased along with the increase of the soil layer,and the climax communities in the successional series and the hydrosere succession series were represented as climax communities in the succession process of the secondary communities.In the community,the accumulation of carbon monoxide in the same soil layer of the three successional series was significantly different.Community types,soil sand/grain ratio and soil water content were the main factors affecting the succession of soils in the mesosere successional series of soils.Community types,soil capillary porosity,soil pH,soil total nitrogen content are the main factors affecting the succession of hydrosere.The main factors for the accumulation of easily-oxidizable organic carbon,community type,biomass of forest litter,and soil total nitrogen content were the main factors affecting the accumulation of easily-oxidizable organic carbon in soils from the xerosere successional series.5.The soil soluble organic carbon in the meosere succession series and the xerosere succession series showed a wave-like trend,the 0-10cm layer was the largest,the 10-20cm layer showed a downward trend,and the 20-40cm layer began to gradually increase,trend.The performance of the hydrosere succession series decreases with the increase of soil layers.The factors affecting the mesosere successional soil series and the hydrosere succession series of soil soluble organic carbon were not yet clear.The main influencing factors of the soil water-soluble organic carbon accumulation in the wet-successive succession series were the biomass of forest litter and soil total nitrogen.6.The comparative analysis of the recalcitrant carbon accumulation showed that the mesoere succession series were greater than hydrosere succession series and xerosere succession series.Accumulation of Soil recalcitrant Carbon in the same succession process were the mesoere succession series than Secondary community;hydrosere succession series was Betula platyphylla-Pinus koraiensis forest than the broadleaved Koraiensis forest.Xerosere succession series was Quercus mongolica-Pinus koraiensis forest than Butula dayurica-Betula dahurica forest.Soil recalcitrant carbon accumulation showed a significant linear positive correlation with soil water content and soil capillary porosity,and a significant linear negative correlation with soil bulk density.7.The contribution of soil mineralizable carbon to total organic carbon was 1.78%-2.17%.The contribution of soil soluble organic carbon to total organic carbon was about 0.52%-1.88%.The contribution rate of primary broad-leaved Korean pine forest and secondary forest of Betula platyphylla was the largest.The total contribution rate of soil organic carbon to the easily-oxidized organic carbon was 3.08%-12.35%,and the contribution rate of the top-level community Quercus mongolica-Pinus koraiensis forest was the largest.The contribution of soil recalcitrant carbon to total organic carbon was 12.75%to 41.47%,of which the contribution rate of primary broad-leaved Korean pine forest was the largest.In summary,the succession of broadleaf-Korean pine forest communities affected soil physicochemical properties,and there were significant differences in soil organic carbon and various components in different successional series.The environmental factors that regulate the accumulation and maintenance of soil organic carbon components in different succession series Community type,community succession stage(history,time).The results of this study reveal the mechanism of accumulation and maintenance of soil organic carbon components in different successional series of broad-leaved Korean pine forests,which could provide scientific reference for accurately predicting the dynamics of carbon sinks in forest ecosystems in the Xiaoxing'an Mountains in China and rationally formulating forest management measures...
Keywords/Search Tags:The broadleaved Korean pine forest, Mesosere series, Hydrosere series, Xerosere series, Soil physical and cheimical properties, Soil mineralizable carbon, Easily-oxidized carbon, Soil water-soluble organic carbon, Soil recalcitrant carbon
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