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阔叶红松(Pinus koraiensis)林是我国东北东部山区的地带性顶极植被,全球氮沉降增加可能影响其碳循环的各个过程。在2010年和2011年的5—10月,对典型阔叶红松林进行了模拟氮沉降实验。实验设置了对照(N_0,0 kg/(hm~2·a))、低氮(N_1,30 kg/(hm~2·a))、中氮(N_2,60 kg/(hm~2·a))和高氮(N_3,120 kg/(hm~2·a))4种模拟氮沉降处理,每隔半个月采用Li-6400-09便携式CO_2/H_2O气体分析仪对土壤呼吸速率进行测定,研究了氮沉降对典型阔叶红松林土壤呼吸的影响。结果表明:1各处理土壤呼吸速率的季节变化与5 cm深度的土壤温度相似,均呈现出明显的季节变化趋势,最大值出现在6月中旬(3.84~4.55μmol/(m~2·s)),最小值出现在5月初(1.37~1.84μmol/(m~2·s)),土壤温度的变化可解释土壤呼吸速率季节变化的499%~692%。2各处理的土壤呼吸速率与土壤温度呈指数相关(R~2=0.499~0.692),土壤呼吸速率与土壤温度、湿度及其相互作用的回归模型可以解释各处理土壤呼吸速率52.2%~73.5%的季节变异;3 N_0、N_1、N_2和N_3样地土壤呼吸温度敏感系数Q10值分别为2.10、1.93、1.97和2.01;4各处理样地土壤呼吸速率的平均值分别为3.09、2.78、3.06和2.90μmol/(m~2·s),与对照样地N_0相比,土壤呼吸速率和凋落物量无明显相关(P>0.05)。
Pinus koraiensis forest is a zonal top vegetation in the eastern mountainous area of northeast China. The increase of global nitrogen deposition may affect the process of carbon cycle. In 2010 and from May to October 2011, simulated nitrogen deposition experiments were conducted on typical Korean pine broad-leaved forests. The experiment set up the control (N 0,0 kg / (hm 2 · a)), low nitrogen (N 1,30 kg / (hm 2 · a)), medium nitrogen (2 60 kg / (hm 2 · a ) And high nitrogen (N 3,120 kg / (hm 2 · a)) were used to measure the soil respiration rate with Li-6400-09 portable CO 2 / H 2 O gas analyzer every half month The effects of nitrogen deposition on soil respiration in a typical broad-leaved Korean pine forest were studied. The results showed that: (1) The seasonal variation of soil respiration rate was similar to that of soil depth of 5 cm, showing a significant seasonal variation. The maximum appeared in mid-June (3.84-4.55 μmol / (m 2 · s) ), And the minimum appeared in early May (1.37 ~ 1.84μmol / (m ~ 2 · s)). The change of soil temperature explained 499% -692% of the seasonal variation of soil respiration rate. The regression model of soil respiration rate and soil temperature exponential (R ~ 2 = 0.499 ~ 0.692), the soil respiration rate and soil temperature, humidity and their interaction can explain the soil respiration rate of 52.2% -73.5% The Q10 values of soil respiration temperature sensitivity in 3 N_0, N_1, N_2 and N_3 plots were 2.10, 1.93, 1.97 and 2.01, respectively. The average values of soil respiration rate in all treatments were 3.09, 2.78, 3.06 and 2.90μmol / (m ~ 2 · s). There was no significant correlation between soil respiration rate and litterfall (P> 0.05) compared with the control plot N_0.