退耕地土壤呼吸的年际变化及其温度敏感性
发布时间：2018-11-03 12:09
【摘要】：土壤呼吸是生态系统碳循环过程中的重要环节之一,深入研究陆地生态系统土壤呼吸的动态变化及其影响因素有着重要意义。目前对土壤呼吸日变化、季节变化的研究相对较多,而对其年际变化的研究相对很少。为深入研究土壤呼吸的年际变化,我们在天龙山地区对一个退耕地和一个裸地的土壤呼吸及其土壤温度和土壤水分进行了为期10年每月1-3次的定位测量。旨在:1)研究退耕地和裸地不同年份土壤呼吸及土壤温度、土壤水分的季节变化以及他们之间的关系;2)研究2个样地土壤呼吸及其温度敏感性的年际变化及其与土壤温度、土壤水分年际变化之间的关系;3)估算2个样地的年土壤呼吸总量;4)量化退耕地的根系呼吸对总土壤呼吸的贡献率。主要研究结果如下:2个样地土壤呼吸及其土壤温度均呈现出明显的季节变化规律:初春偏低、夏季初秋达到最高、秋季逐渐降低、冬季达最低。高斯3参数方程可以很好地模拟土壤呼吸及土壤温度随天数的变化规律。就单个测定年而言,2个样地的土壤水分的季节变化规律不明显,主要取决于降雨量及其季节变化,但是就10个测定年的各月测定的土壤水分平均值而言,土壤水分呈现出“横置S”型特征,即夏末秋初较高、春末夏初较低。退耕地和裸地10年的土壤呼吸均值分别为4.11±3.12μmol·m~(-2)·s~(-1)和2.74±2.35μmol·m~(-2)·s~(-1)。最小值均出现在冬季,且均在1μmol·m~(-2)·s~(-1)之下。10个测定年退耕地和裸地的年碳释放量平均值分别为1208.7 g C m~(-2) a~(-1)和805.8 g C m~(-2) a~(-1),不同测定年不同。10年间退耕地根系呼吸对土壤呼吸的贡献率变化范围为21.73%~42.13%。退耕地与裸地的土壤温度与土壤呼吸的关系均可以用指数方程来描述,在多数测定年,退耕地和裸地的土壤温度对土壤呼吸的解释率分别为55%至92%和40%至84%之间,这表明,退耕地土壤呼吸对土壤温度的依赖性要高于裸地。大多数年份两样地土壤呼吸与土壤水分的关系不显著,但是裸地受土壤水分的影响大于退耕地。与单变量模型相比,包含土壤温度和水分因子的双变量方程可以更好地模拟两样地土壤呼吸的季节变化。拟合模型中的幂指函数模型的拟合效果均优于乘积函数模型。基于5 cm、10 cm、15 cm深度土壤温度计算的退耕地土壤呼吸的温度敏感性值(Q_(10))分别为2.32、2.59、2.75,裸地分别为1.92、2.05、2.18。当进一步把10个测定年土壤水分进行排序分级后进行分析时,退耕地三个测定深度的最大Q_(10)值均出现在土壤水分含量大于21%的区间,而裸地三个深度的最大Q_(10)值出现在土壤水分为16%~21%的区间。基于不同深度的土壤温度计算的土壤呼吸的温度敏感性(Q_(10))值、土壤温度10℃时的土壤呼吸值(R_(10))不同。随着土壤温度测定深度的增加,Q_(10)值呈增加趋势。除个别测定年,退耕地和裸地十年间R_(10)的变化分别在2.2μmol·m~(-2)·s~(-1)左右和1.3μmol·m~(-2)·s~(-1)左右。退耕地Q_(10)值与土壤水分的关系显著,但裸地关系不显著。
[Abstract]:Soil respiration is one of the important links in the process of ecosystem carbon circulation, and it is of great significance to further study the dynamic changes of soil respiration and its influencing factors in terrestrial ecosystem. At present, there are relatively many studies on soil respiration diurnal variation and seasonal variation, but the study of inter-annual variation is relatively rare. In order to further study the inter-annual variation of soil respiration, we measured 1-3 times a month for a 10-year period of soil respiration, soil temperature and soil moisture in Tianlongshan area. aims to: 1) study soil respiration and soil temperature, seasonal variation of soil moisture and their relationship among different years of uncultivated land and bare ground; 2) study the inter-annual variation of soil respiration and its temperature sensitivity in two samples and its relative soil temperature, 3) estimating the annual soil respiration of 2 samples; 4) quantifying the contribution rate of root respiration of cultivated land to total soil respiration. The main results are as follows: 2 samples of soil respiration and soil temperature show obvious seasonal variation: the first spring is low, the first fall of summer reaches the highest, the autumn decreases gradually, and the winter reaches the lowest. The Gauss 3 parameter equation can simulate the change of soil respiration and soil temperature with the number of days. For a single measurement year, the seasonal variation of soil moisture in two samples is not obvious, mainly depending on the rainfall and its seasonal variation, but the soil moisture content is presented in terms of the mean soil moisture mean value measured in every month of ten measurement years. "Transverse S" It is characterized by high early summer and late summer, low early spring and early summer. The average soil respiration of the cultivated land and bare land was 4.11, 3.12. mol 路 m ~ (-2) 路 s ~ (-1) and 2.74 ~ 2.35 umol 路 m ~ (-2) 路 s ~ (-1) respectively. The minimum values appeared in winter and were below 1. m ~ (-2) 路 s ~ (-1). The average annual carbon release in 10 measured years was 1208. 7 g C m ~ (-2) a ~ (-1) and 805. 8 g C m ~ (-2) a ~ (-1), respectively. The contribution rate of respiration to soil respiration was 21.73% ~ 42. 13% in 10 years. The relationship between the soil temperature of the uncultivated land and the bare ground and the soil respiration can be described by exponential equation. In most measures, the rate of soil respiration is 55% to 92% and 40% to 84%, respectively. The dependence of soil respiration on soil temperature was higher than bare ground. In most years, the relationship between soil respiration and soil moisture was not significant, but the effect of soil moisture on bare ground was greater than that of cultivated land. Compared with the single variable model, the double variable equation containing soil temperature and moisture factor can better simulate the seasonal variation of soil respiration. The fitting effect of the power finger function model in the fitting model is better than that of the product function model. The temperature sensitivity of soil respiration (Q _ (10)) calculated on 5 cm, 10 cm and 15 cm depth soil temperature was 2.32, 2.59, 2.75, respectively. The bare ground was 1.92, 2.05, 2.18, respectively. The maximum Q _ (10) value of the three measuring depths of the uncultivated land appeared in the interval of more than 21%, while the maximum Q _ (10) value of the three depths in bare land appeared in the interval of 16% ~ 21%. Temperature sensitivity (Q _ (10)) of soil respiration calculated based on soil temperature at different depths is different from soil respiration value (R _ (10)) at 10 鈩，
本文编号：2307746
[Abstract]:Soil respiration is one of the important links in the process of ecosystem carbon circulation, and it is of great significance to further study the dynamic changes of soil respiration and its influencing factors in terrestrial ecosystem. At present, there are relatively many studies on soil respiration diurnal variation and seasonal variation, but the study of inter-annual variation is relatively rare. In order to further study the inter-annual variation of soil respiration, we measured 1-3 times a month for a 10-year period of soil respiration, soil temperature and soil moisture in Tianlongshan area. aims to: 1) study soil respiration and soil temperature, seasonal variation of soil moisture and their relationship among different years of uncultivated land and bare ground; 2) study the inter-annual variation of soil respiration and its temperature sensitivity in two samples and its relative soil temperature, 3) estimating the annual soil respiration of 2 samples; 4) quantifying the contribution rate of root respiration of cultivated land to total soil respiration. The main results are as follows: 2 samples of soil respiration and soil temperature show obvious seasonal variation: the first spring is low, the first fall of summer reaches the highest, the autumn decreases gradually, and the winter reaches the lowest. The Gauss 3 parameter equation can simulate the change of soil respiration and soil temperature with the number of days. For a single measurement year, the seasonal variation of soil moisture in two samples is not obvious, mainly depending on the rainfall and its seasonal variation, but the soil moisture content is presented in terms of the mean soil moisture mean value measured in every month of ten measurement years. "Transverse S" It is characterized by high early summer and late summer, low early spring and early summer. The average soil respiration of the cultivated land and bare land was 4.11, 3.12. mol 路 m ~ (-2) 路 s ~ (-1) and 2.74 ~ 2.35 umol 路 m ~ (-2) 路 s ~ (-1) respectively. The minimum values appeared in winter and were below 1. m ~ (-2) 路 s ~ (-1). The average annual carbon release in 10 measured years was 1208. 7 g C m ~ (-2) a ~ (-1) and 805. 8 g C m ~ (-2) a ~ (-1), respectively. The contribution rate of respiration to soil respiration was 21.73% ~ 42. 13% in 10 years. The relationship between the soil temperature of the uncultivated land and the bare ground and the soil respiration can be described by exponential equation. In most measures, the rate of soil respiration is 55% to 92% and 40% to 84%, respectively. The dependence of soil respiration on soil temperature was higher than bare ground. In most years, the relationship between soil respiration and soil moisture was not significant, but the effect of soil moisture on bare ground was greater than that of cultivated land. Compared with the single variable model, the double variable equation containing soil temperature and moisture factor can better simulate the seasonal variation of soil respiration. The fitting effect of the power finger function model in the fitting model is better than that of the product function model. The temperature sensitivity of soil respiration (Q _ (10)) calculated on 5 cm, 10 cm and 15 cm depth soil temperature was 2.32, 2.59, 2.75, respectively. The bare ground was 1.92, 2.05, 2.18, respectively. The maximum Q _ (10) value of the three measuring depths of the uncultivated land appeared in the interval of more than 21%, while the maximum Q _ (10) value of the three depths in bare land appeared in the interval of 16% ~ 21%. Temperature sensitivity (Q _ (10)) of soil respiration calculated based on soil temperature at different depths is different from soil respiration value (R _ (10)) at 10 鈩，
本文编号：2307746
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