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Simulation Studies on Temperate Forest Soil CO2 and N2O Emissions and Nitrogen Net Mineralization after Water and Thermal Changes

Author: WangYing
Tutor: LiTuanSheng；XuXingKai
School: Chang'an University
Course: Physical Geography
Keywords: Changes in the hydrothermal CO2 N2O Nitrogen net mineralization qCO2
CLC: S714
Type: Master's thesis
Year: 2011
Downloads: 50
Quote: 0
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Abstract


In this paper, the Changbai Mountain in broadleaved Korean pine forest, secondary poplar birch, ginseng cultivation in three different vegetation types in different soil depth, soil (0-10 cm ,10-20 cm and 20-30 cm) for the object, by laboratory simulation to study the impact of changes in hydrothermal library of the soil activated carbon nitrogen, two greenhouse gases CO2, N2O emissions and nitrogen net mineralization. The paper consists of three parts: the first study hydrothermal changes include frequent freezing and thawing process, air-dried soil re-wetting of this wet and dry process on the soil activated carbon nitrogen library. After frequent soil freezing and thawing process in the first part of the second use of research in the case to add or not to add a nutrient source, add the acetylene gas nitrogen pool of soil active carbon, C02 and N20 emissions, as well as net nitrogen transformation process. The third use of air-dried topsoil regulate different water content, and to study the different air-dried soil wetting intensity, and different temperatures on the library of the soil activated carbon nitrogen, C02 and N20 emissions as well as the impact of nitrogen transformation. The main conclusions are: (1) experience frequent freezing and thawing process, the soil organic carbon and microbial carbon and nitrogen solubility decreased, allelopathic TN content increased. Frequent freezing and thawing alternately of these indicators have a very significant impact. Different vegetation types, soil net mineralization Korean pine forest of, gt; Yang birch, gt; ginseng cultivation. With the increase of soil depth, soil net mineralization gradually reduced. (2) air-dried soil re-wetting, that regulate different water content, compared with the original soil that is not air-dried, DOC, TN content increased microbial carbon and nitrogen content decreased. Korean pine forest and Young birch KCI net nitrogen mineralization system reached maximum moisture content of 60%, while ginseng cultivation KCI net nitrogen mineralization system reached maximum 80% moisture content. Net nitrogen mineralization Young birch gt; Korean pine forest gt; ginseng cultivation. (3) not add soil nutrient source, add the acetylene gas CO2 emissions, while in the case of a sufficient source of nutrition, add acetylene gas CO2 emissions reduction. The results show that the study of qCO2 elevated make qCO2 value of acetylene gas by reducing microbial carbon content. Inhibitory effect of acetylene on soil autotrophic nitrification in the soil not add nutritional source more obvious, and acetylene gas reduced net nitrogen mineralization. Different treatment, the CO2 cumulative emissions and salt extraction DOC, microbial carbon and nitrogen was significantly positively related; to add nutritional source and acetylene gas in soil, N20 cumulative emissions of soil active carbon nitrogen indicators has nothing to do. (4) under the same conditions of humidity, doc, TN The content and CO2 emissions with increasing temperature increases, the microorganisms carbonitride content is reduced as the temperature rises. N2O emissions is not consistent regularity. The temperature is 15 ℃ and 25 ℃, the temperature is qCO2, CO2 emissions of the main factors of the Q10 value. When the temperature rises to 35 ° C, the water has an important influence on the two indicators. Correlation analysis showed: under different temperature conditions, CO cumulative emissions and flooding mentioning DOC, microbial carbon and nitrogen was significantly positively related to soil moisture. N2O cumulative emissions and soil moisture was a significant positive correlation was significantly negatively correlated with the amounts of mineralized. Only in 25 ℃, qCO2 the soil moisture content was a significant positive correlation.

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