南方红壤区3年生茶园土壤呼吸特征

为探讨南方红壤区茶园的土壤呼吸特征,采用LI-Cor8100开路式土壤碳通量测定系统观测3年生茶园系统的土壤呼吸速率,对茶园土壤呼吸速率的季节变化和在茶行尺度上的空间异质性进行了研究。结果表明,茶园土壤呼吸速率的月动态变化呈明显的单峰曲线特征,峰值出现在8月;茶园土壤呼吸速率的月动态变化与温度呈极显著相关(P<0.01),土壤10 cm的温度能够解释茶园不同观测区域土壤呼吸速率月动态变化的67.79%~88.52%;用指数方程计算的茶园不同观测区域土壤呼吸Q10值为1.58~1.86。在茶行尺度上,茶园土壤呼吸速率存在明显的空间异质性,土壤呼吸速率通常在距离茶树基部较近的位置较高;根系生物量能够解释茶园土壤呼吸速率在茶行尺度上空间变异的82.68%。因此,根系分布的空间差异是造成茶园土壤呼吸速率空间异质性的主要原因。

Soil Respiration Characteristics of 3-year-old Tea Garden from Red Soil Region in South China

In order to understand soil respiration characteristics of tea garden from Red Soil Region in South China, soil respiration rate in a 3-year-old tea garden were investigated with LI-Cor8100 open soil carbon flux system from January to December in 2011. The seasonal variation and spatial heterogeneity of soil respiration rate were studied. The results showed that monthly dynamic changes of soil respiration rate in the tea garden correlated significantly with temperature (P<0.01). Soil temperature at 10 cm depth could explain 67.79%-88.52% of monthly dynamic changes of soil respiration at four observation areas in the tea garden. The Q₁₀ value of soil respiration derived from the exponential equation at different observation areas in tea garden ranged from 1.58 to 1.86. There was obvious spatial heterogeneity for soil respiration at tea line scale in tea garden, the soil respiration rate was higher close to tea tree base. The spatial variation of root biomass could explain 82.68% of spatial heterogeneity of soil respiration rate. So, the difference in spatial distribution of roots was main reason for spatial heterogeneity of soil respiration rate.