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Effect Of Simulated Nitrogen Deposition On The Soil Respiration And Photosynthesis Of Schima Superba And Cinnamomum Camphora

Posted on:2012-11-13Degree:MasterType:Thesis
Country:ChinaCandidate:M N YouFull Text:PDF
GTID:2213330368979281Subject:Ecology
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The increasing human activities and the extensive using of fossil fuels and fertilizer as well as development of animal husbandry emit a large number of nitrogen compounds, causing more and more serious environmental stresses such as affecting the normal growth of plants. At present, nitrogen deposition has become a hot topic in the international ecological and environmental research. Nitrogen is the essential for the growth of plant and is the element of material in leaf. Nitrogen deposition changes N cycle of ecosystem and influence the structure and function of ecosystem, the productivity of plant, pattern of competition of plant as well as compositions and diversity of species. The subtropical forest region in China seriously impacted by the nitrogen deposition due to the atmosphere pollution which caused as economic development rapidly. Cinnamomum camphora and Schima superba are typical subtropical evergreen trees, In general, S.superba grows in relatively nutrient-poor soils, whereas Cinnamomum camphora grows in relatively nutrient-rich soils. In an effort to understand the impacts of nitrogen deposition on ecophysiology of Cinnamomum camphora seedling and Schima superba seedling and compare this effect between the two tropical tree species of different species-N-requirement, we reported the results of an experiment, which is the two-years old seedlings treated with N as NH4NO3 at CK(0gNm-2yr-1),Lower Nitrogen (LN: 6gNm-2yr-1), Medium Nitrogen (MN: 12gNm-2yr-1)Higher Nitrogen(HN: 24gNm-2yr-1), to character ecophysiological parameters(photosynthesis, soil respiration and growth ), the Conclusions are below:Firstly, the photosynthetic response of the two subtropical tree species of different species-N-requirement to nitrogen deposition is different, For Schima superba seedling, the addition of nitrogen deposition promotes the photosynthesis in June 2009, September 2009, and has no influence in December 2009, decreasing its photosynthesis in April 2010; while Cinnamomum camphora seedling is highly sensitive to N deposition under the quantity of current atmospheric nitrogen deposition, In September 2009 and April 2010, the addition of nitrogen deposition decreased its photosynthesis, In June 2009 and December 2009, nitrogen deposition has no influence on the photosynthesis of Cinnamomum camphora seedling. Secondly, For the two subtropical tree species of different species-N-requirement, the change of gas exchange parameters across multiple nitrogen deposition is line with the change of photosynthesis across multiple nitrogen deposition.Thirdly, the response of soil respiration of Schima superba and Cinnamomum camphora to nitrogen deposition rate is different in different seasons.Fourthly, the effect of temperature and moisture on photosynthesis of the two subtropical tree species of different species-N-requirement is different in the certain nitrogen deposition rate. With the increasing of nitrogen deposition rate, the effect of temperature and moisture on photosynthesis of Schima superba increase. While, for Cinnamomum camphora, the response of photosynthesis to temperature and moisture is the highest value in LN.Fifthly, the effect of soil temperature on soil respiration of Schima superba is greater than Comprehensive effect of temperature and moisture of soil. It is contrary to Cinnamomum camphora.
Keywords/Search Tags:nitrogen deposition, Cinnamomum camphora, Schima superba, Photosynthesis, soil respiration
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