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于2007年10月—2008年9月,利用Li-6400便携式光合作用仪配合土壤呼吸气室对南京中山植物园内草坪、疏林和近自然林3种植被类型的土壤呼吸速率的季节变化及其影响因子进行了测定。结果表明:不同植被类型土壤呼吸速率具有明显的季节变化,夏季(8月)较高,近自然林、疏林和草坪类型分别为3.28、4.07和7.58μmol.m-2.s-1,冬季(12月)最低,近自然林、疏林和草坪类型分别为0.82、0.99和1.42μmol.m-2.s-1;不同植被类型的年均土壤呼吸速率有显著差异(P<0.05),平均土壤呼吸速率大小排序为草坪>疏林>近自然林;不同植被类型的土壤呼吸速率与土壤温度呈显著性指数相关关系,与土壤含水率无显著相关关系;Q10值均随着土层深度的增加而增加;不同植被类型的Q10值存在一定程度的差异,近自然林类型的Q10值大于草坪和疏林类型的Q10值。研究表明,城市如果大量发展草坪可能增加土壤CO2的排放。
From October 2007 to September 2008, the seasonal variations of soil respiration rate in the three vegetation types of turfgrasses, sparse forests and near-natural forests in Zhongshan Botanical Garden of Nanjing, China were measured using a Li-6400 portable photosynthesis system coupled with a soil respiration plenum Influencing factors were determined. The results showed that the soil respiration rate of different vegetation types had obvious seasonal changes, which were higher in summer (August), and were 3.28, 4.07 and 7.58μmol.m-2.s-1 in winter, near natural forest, sparse forest and turf (December) and 0.82, 0.99 and 1.42 μmol.m-2.s-1 for the natural forests, sparse forests and turfgrasses, respectively. The average annual soil respiration rates of different vegetation types were significantly different (P <0.05) The average soil respiration rate ranked in the order of lawn> sparse forest> near natural forest. The soil respiration rate of different vegetation types had a significant exponential relationship with soil temperature, and had no significant correlation with soil moisture content. Q10 values varied with soil depth Q10 values of different types of vegetation have some degree of difference, Q10 values of near-natural forest types are higher than those of lawn and sparse forest types. Research shows that large-scale urban development of turfgrass may increase soil CO2 emissions.