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为了解不同降雨条件下碳在常绿阔叶林和针叶林内部的迁移特征,对亚热带米槠次生林和杉木人工林在不同降雨量下林冠层可溶性有机碳(DOC)浓度的变化特征进行分析。结果发现:降雨量大于10mm时,米槠和杉木树干径流量与胸径呈幂函数正相关(R2>0.81和R2>0.88),米槠树干径流中DOC浓度与胸径呈幂函数负相关(R2>0.37);相反,杉木树干径流中DOC浓度与胸径呈幂函数显著正相关关系(R2>0.69,P<0.05)。米槠次生林穿透雨中DOC浓度相对大气降雨中DOC浓度平均增量大于杉木人工林,且前者增量的变化幅度也远大于后者,表明降雨量对米槠次生林穿透雨DOC浓度的影响较杉木人工林大;总体而言,米槠次生林树干径流DOC浓度(48.8mg/L)显著低于杉木人工林(23.4mg/L)(P<0.05)。随着降雨量增大,米槠次生林树干径流DOC浓度呈现下降趋势,而杉木人工林则呈现一定的递增趋势,说明树种的差异可引起树干径流DOC浓度对降雨变化的响应不同,降雨历时同样对穿透雨和树干径流DOC浓度具有显著性影响。
In order to understand the migration characteristics of carbon in the evergreen broad-leaved forest and the coniferous forest under different rainfall conditions, the changes of dissolved organic carbon (DOC) in the secondary canopy forest and the Chinese fir plantation at different rainfalls were analyzed . The results showed that when the rainfall was more than 10 mm, the runoffs of rice and fir were positively correlated with the DBH (R2> 0.81 and R2> 0.88), and the DOC concentrations were negatively correlated with the DBH (R2> 0.37). In contrast, the DOC concentration in trunk creek runoff showed a significant positive correlation with DBH (R2> 0.69, P <0.05). The mean concentration of DOC in rice secondary forest through rain is higher than that under atmospheric rainfall. The increase of DOC concentration is larger than that of Cunninghamia lanceolata plantation, indicating that the effect of rainfall on the concentration of DOC in secondary forest is lower than that of the latter In general, the DOC concentration (48.8 mg / L) was significantly lower than that of Chinese fir plantation (23.4 mg / L) (P <0.05). With the increase of rainfall, the DOC concentration in the trunk runoff of M. mongolicata showed a declining trend, but the Cunninghamia lanceolata plantation showed a certain increasing trend, indicating that the differences in tree species could cause the response of the trunk stream DOC to rainfall to vary, Penetration of rain and trunk runoff DOC concentration had a significant effect.