侧柏林土壤呼吸速率对不同模拟降雨量的响应

为了研究不同林龄的森林土壤呼吸速率对不同降雨量的响应规律,选取北京市鹫峰国家森林公园内的30年生和10年生侧柏林作为代表树种,进行了模拟降雨控制试验,并采用碱液吸收法,对5,10,20和50mm降雨量及连续相同频率降雨条件下不同林龄侧柏林的土壤呼吸速率进行了测定。结果表明,林龄对侧柏林的土壤呼吸速率影响有显著差异(p0.05)。30年生侧柏林的土壤呼吸速率总体上高于10年生侧柏林。与对照组相比5,10和20mm降雨量对30年生侧柏林的土壤呼吸速率有促进作用,而50mm降雨量及连续相同频率的降雨对30年生侧柏林土壤呼吸则产生抑制作用。10年生侧柏林与30年生侧柏林相比需水量较小,只有5mm降雨量条件下对其土壤呼吸速率产生了促进作用,其余模拟降雨量均对其产生抑制作用。

Response of Soil Respiration Rate to Different Amounts of Simulated Rainfall in Platycladus Orientalis

A simulated rainfall experiment was conducted to detect the response of forest soil respiration to precipitation change in the Jiufeng National Forest Park, Beijing City. Platycladus orientalis was chosen as the representative tree. Soil respiration rate in different stand ages was measured in conditions of 5, 10, 20 and 50 mm rainfall depths and consecutive identical frequency. Results indicated that there was significant variation(p<0.05) in the impact of stand age on soil respiration rate of Platycladus orientalis, and the soil respiration of 30-years-old Platycladus orientalis generally exceed that of 10-years-old. Compared with control group, 5,10 and 20 mm rainfall tests all had auxo-action effects on soil respiration of 30-years-old Platycladus orientalis and 50 mm rainfall and consecutive identical frequency were suppressive on 30-years-old Platycladus orientalis' soil respiration. 10-years-old Platycladus orientalis needed less water than 30-years-old Platycladus orientalis and hence, only 5 mm rainfall could promote soil respiration rate, while the others presented suppressive effect.