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The Seasonal Dynamics Of Soil Nitrogen Mineralization On Fertilization In Soils Of Cinnamomum Camphora And Pinus Elliottii

Posted on:2013-02-12Degree:MasterType:Thesis
Country:ChinaCandidate:D Y ZhaoFull Text:PDF
GTID:2213330371499045Subject:Ecology
Abstract/Summary:PDF Full Text Request
We made a continuous investigation of soil N availability and N mineralization from July2010to April2011in Cinnamomum camphora and Pinus elliottii ecosystem in Hunan Botanical Garden by using resin-core method. In order to reveal the effects of different carbon input and nitrogen input on soil nitrogen mineralization, we executed some treatments to the trees investigated including carbon input and nitrogen input, a. fertilizing soil with different Concentration gradient N (LN:5g·m-2, MN:15g·m-2,HN:30g·m-2). b. litter exclusion to control carbon input. c. litter redouble to add carbon input. The results were as follows:(1) Available nitrogen content was significantly different in different seasons both in Cinnamomum camphora and Pinus elliottii communities. Available nitrogen content climbed to the top at October and declined to the bottom at April in Cinnamomum camphora, and at January in Pinus elliottii. Ammonia showed a dominant part in gross available nitrogen of this two forest types, which was69.6%-96.4%and73.2%-92.3%of Cinnamomum camphora and Pinus elliottii, respectively.(2) Seasonal differences between two forest types in the soil net nitrogen mineralization rate were significant. Available soil nitrogen net accumulation at October and April in Cinnamomum camphora, amount of net nitrogen mineralization was positive. Available soil nitrogen net consumption at January and July, amount of net nitrogen mineralization was negative. Nitrogen mineralization showed a net accumulation in all over the year except October in Pinus elliottii. Annual amount of net nitrogen mineralization of this two forest types was66.06kgN·hm-2and42.73kgN·hm-2(for0cm-15cm soil layer)(3) After nitrogen fertilizer treatment, the nitrogen mineralization increased with fertilizer concentration at January, April and July. The declining trend appeared when the fertilizer of high nitrogen concentration on October, but still higher than the control. It indicated that nitrogen fertilizer can increase soil nitrogen mineralization rate in Cinnamomum camphora. It also showed that fertilization increased the soil ammonium nitrogen content and ammonification rate significantly in the two forest types.(4) Litter exclusion and litter redouble treatments significantly increased ammonium and available nitrogen concentration. Ammonium and available nitrogen concentration of litter exclusion were higher than litter redouble.However, there was no effect of nitrate nitrogen on Litter exclusion and litter redouble.
Keywords/Search Tags:Cinnamomun camphora, Pinus elliottii, nitrogen mineralization, litter, fertilizer
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