城市绿地土壤呼吸与土壤温度土壤水分的关系研究

Soil respiration and its relations to environmental factors over three urban vegetation covers

采用LICOR-6400便携式光合作用仪连接6400-09土壤叶室,对山西大学校园内的三种绿地（黑麦草、紫叶小檗和日本黄杨）的土壤呼吸进行了一年的测定。结果表明：土壤呼吸速率具有较明显的季节变化,冬春季较低,盛夏秋初较高,最大值出现在8月,最低值出现在12月。土壤呼吸速率与0-10 cm深度的土壤温度关系显著,黑麦草、紫叶小檗和日本黄杨土壤温度变化分别解释土壤呼吸季节变化的57.3%、65.4%、46.6%（线性函数）和60.6%、71.3%、50.7%（指数函数）;黑麦草地土壤呼吸与土壤水分的关系均为极显著（p〈0.01）;用土壤温度和土壤水分的复合方程可以解释土壤呼吸变化的52%-84%。黑麦草、紫叶小檗和日本黄杨的年土壤呼吸总量分别为1.246 kg C.m^-2、1.822 kg C.m^-2、1.806 kg C.m^-2。

With the development of urbanizations more and more vegetation lands in the city have been built, however, the research on soil respiration for urban vegetation was seldom reported. As one of the important facfors effecting global warming, soil CO2 efflux from different ecosystems have been observed, so it is need to make research about how much soil CO2 released from urban vegetation system. The objectives of this study is to examine seasonal patterns of soil efflux of three kinds of urban vegetation and to estimate the amount of soil CO2 efflux from the soil and to understand the relationships between soil CO2 efflux and soil temperature as well soil water content. From March to December of 2007 we measured soil-surface CO2 efflux from 3 kinds of vegetation ： ryegrass （Lolium perrnne）, Japan Barberry （Berberis thunbergii） and Japan Euonymus （Euonymus japonicus） located in the campus of Shanxi University, with an infrared gas analyzer （IRGA） attaching a 6400 -09 chamber. It was found that soil respiration rate showed an asymmetric seasonal pattern, with the lower values in winter and spring months and the higher values in the middle summer and the beginning of autumn. The maximum value of the respiration appeared in August and the minimum one in December. The relationships between soil respiration rate and soil temperature at 10 cm depth can be described with the linear or exponential equations. Using the data excluding the water stressed, the soil temperature respectively explained 57.3%, 65.4% ,46.6% （linear equation） and 60.6%, 71.3%, 50.7% （exponential equation） of temporal variation in soil respiration. Before and after the standardization by soil temperature the relationship between the soil respiration and soil water content was significant （p 〈0.01 ） for 3 kinds of vegetation. The models including both temperature and soil water content explained 52% - 84% of the variation in soil efflux. Annual soil CO2 emission from the surface of land of ryegrass （Lolium perrnne） , Japan Barberry （Berberis thunbergii） and Japan Euonymus （Euonymus japonicus） was about 1. 246 kg C · m^-2, 1.822 kg C · m^-2 and 1. 806 kg C · m^-2, respectively.