中文摘要：

采用野外定点观测和统计分析的方法,对宝鸡市疏林地和草地土壤CO2通量进行了观测研究。结果表明,疏林地、草地的土壤表层呼吸日动态变化为单峰曲线,草地土壤呼吸速率大于疏林地,分别为2.37、1.83μmol/（m2獉s）。土壤表层温度与土壤呼吸速率之间呈指数函数关系,而土壤含水率与土壤呼吸的日动态相关关系不显著,水分并非是限制城市绿地土壤呼吸的关键因子;土壤呼吸与土壤全N、土壤容重、总孔隙度、土壤质地极显著正相关（P〈0.01）,而与土壤速效P、全P、有机质和p H值之间无显著相关性。因此,在城市绿地环境建设中,应通过适当的种植措施来改善土壤理化性质,熟化土壤的同时,采用人工灌溉和发展复合型疏林结构植被来减少城市土壤CO2的排放量。

英文摘要：

The soil CO2 fluxes of urban open forest land and grassland in Baoji city were studied by adopting the methods of field fixed-point observation and statistical analysis. The daily dynamic change in surface soil respiration of open forest land and grassland showed an unimodal curve, and the surface soil respiration rate of grassland and open forest land was 2.37 and 1.83 μmol/（ m2· s）, respectively. The relationship between surface soil temperature and soil respiration rate was of exponential func- tion. The soil moisture content had no a significant correlation with the daily dynamics of soil respiration, so the key factor restric- ting the soil respiration in urban green land was not the soil moisture content. Soil respiration rate was positively correlated with soil total nitrogen content, soil bulk density, soil total porosity, and soil texture （P〈0.01）, while it had no a correlation with soil a- vailable phosphorus, total phosphorus, organic matter content, and soil pH-value. Therefore, in the construction of urban green land, some proper planting measures should be taken to improve soil physical and chemical properties, and the urban soil CO2 e- mission should be reduced by adopting artificial irrigation and developing forest-grass composite vegetation system.