不同有机质含量土壤CO_2排放季节变化规律及差异研究

Study on seasonal variation of soil carbon dioxide emissions under different contents of soil organic matter

为探究不同耕层土壤有机质含量条件下土壤CO2排放通量变化特征与有机质含量关系,设计耕层土壤6个不同有机质含量处理。通过对土壤CO2排放定位连续观测,研究耕层土壤不同有机质含量条件下土壤CO2排放季节变化规律,分析土壤CO2排放与耕层土壤有机质含量关系。结果表明,土壤CO2通量呈单峰曲线季节变化,与地温和气温变化一致;一次方程、二次方程和指数方程均可模拟土壤CO2通量与地温和气温关系,指数方程拟合效果优于一次方程和二次方程。土壤CO2排放最大通量、平均通量、排放总量与耕层土壤有机质呈单峰曲线变化关系,二次方程拟合效果良好;当耕层土壤有机质含量分别为64.50、54.32、59.80 g·kg-1时,土壤CO2排放最大通量、土壤CO2排放平均通量、土壤CO2排放总量达到最大值。

In order to explore the variation of soil carbon dioxide fluxes under the condition of different topsoil organic matter and the relationship between soil carbon dioxide emissions and the content of soil organic matter, six levels of organic matter treatments was designed. The law of soil carbon dioxide emissions＇ seasonal vitiation and the effects of the topsoil organic matter content were explored by investigating the soil carbon dioxide emissions with different level of topsoil organic matter, and continually monitoring at fixed sample plots, and then the relationship among soil carbon dioxide emissions and the topsoil organic matter content was analysed. The results showed that soil carbon dioxide emission flux had obvious seasonal, showing a single peak curve. It was same as ground temperature and air temperatura＇s seasonal variation. Linear equation, quadratic equation and exponential equation could simulate the relationship between soil carbon dioxide flux and temperature. The exponential equation was better than the linear equation and quadratic equation. The relation of topsoil organic matter content to soil carbon dioxide emission maximum flux, soil carbon dioxide emission average flux, soil carbon dioxide total emissions were expressed in a single curve, and quadratic equation fit with good results. Soil carbon dioxide emission maximum flux, soil carbon dioxide average flux, soil carbon dioxide total emissions reached the maximum with topsoil organic matter content of 64.50, 54.32 and 59.80 g ·kg-1, respectively.