南京城市公园绿地不同植被类型土壤呼吸的变化

子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7.58 μmol·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1.42 μmol·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;Q_(10)值均随着土层深度的增加而增加;不同植被类型的Q_(10)值存在一定程度的差异,近自然林类型的Q_(10)值大于草坪和疏林类型的Q_(10)值.研究表明,城市如果大量发展草坪可能增加土壤CO_2的排放.

Abstract：

By using Li-6400 portable photosynthetic apparatus connected to soil chamber,the soil respiration rate under three vegetation types(lawn,open woodland,and close-to-nature forest)in Nanjing Zhongshan Botanical Garden was measured from October 2007 to September 2008,with related affecting factors analyzed.The soil respiration rate had obvious seasonal fluctuation,being the highest in summer(August)and the lowest in winter(December).For the close-to-nature forest,open woodland,and lawn,their soil respiration rate in summer was 3.28,4.07,and 7.58μmol·m~(-2)·s~(-1),and that in winter was 0.82,0.99,and 1.42μmol·m~(-2)·s~(-1),respectively.The annual mean soil respiration rate differed significantly with vegetation type(P＜0.05),which was in order of close-to-nature forest＜open woodland＜lawn.The soil respiration rate had significant exponential correlation with soil temperature,but no correlation with soil moisture.The Q_(10) value increased with increasing soil depth,and was larger in close-tonature forest than in open woodland and lawn.Our results indicated that the rapid development of lawn in urban green space could increase the urban soil CO_2 emission.

Soil respiration under different vegetation types in Nanjing urban green space

By using Li-6400 portable photosynthetic apparatus connected to soil chamber,the soil respiration rate under three vegetation types(lawn,open woodland,and close-to-nature forest)in Nanjing Zhongshan Botanical Garden was measured from October 2007 to September 2008,with related affecting factors analyzed.The soil respiration rate had obvious seasonal fluctuation,being the highest in summer(August)and the lowest in winter(December).For the close-to-nature forest,open woodland,and lawn,their soil respiration rate in summer was 3.28,4.07,and 7.58μmol·m~(-2)·s~(-1),and that in winter was 0.82,0.99,and 1.42μmol·m~(-2)·s~(-1),respectively.The annual mean soil respiration rate differed significantly with vegetation type(P＜0.05),which was in order of close-to-nature forest＜open woodland＜lawn.The soil respiration rate had significant exponential correlation with soil temperature,but no correlation with soil moisture.The Q_(10) value increased with increasing soil depth,and was larger in close-tonature forest than in open woodland and lawn.Our results indicated that the rapid development of lawn in urban green space could increase the urban soil CO_2 emission.