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太原晋祠地区曾经是著名的稻米之乡,随着晋祠泉的断流,区内土地利用从之前的以水稻田为主转变为以玉米和果园为主.因此,研究土地利用变化后土壤呼吸对于准确估算区域碳循环具有一定意义.基于此目的,本研究以原来为稻田、现为果园利用方式的样地为对象,对其土壤呼吸进行了7 a(2006~2012年)、每月1~3次的定位观测,分析了土壤呼吸的年际、季节变化及其与环境因子年际、季节变化的关系.结果表明,土壤呼吸与土壤温度的季节变化与天数的关系可以用3参数高斯方程模型进行拟合.土壤呼吸的季节变化与土壤温度的季节变化关系为极显著的指数关系,但其与土壤水分季节变化的关系不显著.土壤呼吸速率年平均值为(5.32±3.31)μmol·(m~2·s)-1;碳通量年平均值为1 690.2 g·m-2,在1 294.0~2 006.0g·m~(-2)之间变化,年际均值差异不显著.土壤呼吸的温度敏感性指数(Q_(10))值的年际变化以5、10和15 cm温度测定深度计算分别在1.54~2.20、1.68~2.48和1.82~2.46之间;土壤温度10℃对应的土壤呼吸(R_(10))值的年际变化在2.37~2.81、2.43~3.13和2.59~3.47μmol·(m~2·s)-1之间;Q_(10)和R10值均随土壤温度测定深度增加而增加.Q_(10)的年际变化与10 cm深度的土壤温度(T_(10))的年际变化关系极显著(P=0.016),与其它因子的关系不显著;在拟合方程中增加土壤水分因子不能提高对Q_(10)年际变化的预测精度,说明在本样地水分对Q_(10)的影响较小.R10值的年际变化与环境因子的年际变化关系不显著.与土壤呼吸与土壤温度的单因素模型相比,土壤温度和土壤水分的双变量指数模型可以提高预测土壤呼吸季节变化的准确性.研究结果可以为本地区及同类地区的土壤呼吸估算提供一定参考.
As the famous Jinci area in Taiyuan, Jinci was once the famous land of rice. With the cutoff of Jinci Spring, the land use in the area changed from mainly paddy fields to corn and orchards. Therefore, after studying land use change, Accurate estimation of the regional carbon cycle is of some significance.For this purpose, this study aimed at the plots that used to be paddy fields and presently used as orchards for soil respiration for 7 years (from 2006 to 2012) The results showed that the relationship between the seasonal variation of soil respiration and soil temperature and the number of days could be described by the 3-parameter Gaussian equation The seasonal variation of soil respiration and seasonal variation of soil temperature were highly significant exponential relationship, but the relationship between seasons and seasonal variation of soil moisture was insignificant.The average annual soil respiration rate was (5.32 ± 3.31) μmol · (m ~ 2 · s) -1. The average annual flux of carbon flux was 1 690.2 g · m-2, which varied from 1 294.0 ~ 2 006.0 g · m -2. Soil respiration temperature sensitivity index (Q_ (10)) value The interdecadal variations of soil respiration (R_ (10)) at 5, 10 and 15 cm were 1.54 ~ 2.20, 1.68 ~ 2.48 and 1.82 ~ 2.46, respectively. ~ 2.81, 2.43 ~ 3.13 and 2.59 ~ 3.47μmol · m ~ 2 · s -1, respectively.The Q_ (10) and R_ (10) values all increased with the depth of soil temperature increasing.The annual variation of Q_ (10) The interdecadal variation of soil temperature (T_ (10)) at 10 cm depth was significant (P = 0.016), which was not significantly related to other factors. Increasing soil moisture factor in the fitting equation did not improve Q_ (10) years The results show that the water has little effect on Q_ (10) in this plot.The inter-annual variation of R10 is not related to the interannual variability of environmental factors.Compared with the single factor model of soil respiration and soil temperature The bivariate exponential model of soil temperature and soil moisture can improve the accuracy of predicting the seasonal variation of soil respiration.The results of this study can provide reference for estimating soil respiration in this area and similar areas.