Net primary production and light use efficiency in a mixed coniferous forest in Sweden
Net primary production and light use efficiency in a mixed coniferous forest in Sweden
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DOI：
10.1111/j.1365-3040.2004.01280.x
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发表时间：
2005-03-01
影响因子：
7.3
通讯作者：
Lindroth, A
中科院分区：
文献类型：
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作者：
Lagergren, F;Eklundh, L;Lindroth, A
净初级生产力(NPP)的简单光能利用效率(Epsilon)模型最近受到了极大的关注(NPP=epsilon x吸收的光合作用有效辐射)。然而，在不到一个月的时间步长上，对潜在关系的研究还不多。在这项研究中，日净初级生产力被估计为瑞典松云混交林的净生态系统交换(NEE)和异养呼吸(R-h)的总和。NEE由涡旋相关技术测量，R-h由森林地被呼吸(R-f)和R-f的根份额估算。年均NPP为810gCm(-2)a(-1)，年平均NPP为0.58~0.71gCmJ(-1)，与其他研究相比偏高。Epsilon在4~9月有一个相对恒定的水平，约为0.90g C mJ(-1)。日截获辐射大于6mJ m(-2)d(-1)时，日净初级生产力没有增加，表明净初级生产力的年际变化不直接依赖于总Q(I)。白天的平均温度约为15摄氏度时，光的利用效率最高。在白天，1400帕以上的蒸汽压力差大约减少了50%。
Simple light use efficiency (epsilon) models of net primary production (NPP) have recently been given great attention (NPP = epsilon x absorbed photosynthetically active radiation). The underlying relationships have, however, not been much studied on a time step less than a month. In this study daily NPP was estimated as the sum of net ecosystem exchange (NEE) and heterotrophic respiration (R-h) of a mixed pine and spruce forest in Sweden. NEE was measured by eddy correlation technique and R-h was estimated from measurements of forest floor respiration (R-f) and the root share of R-f. The total yearly NPP was on average 810 g C m(-2) year(-1) for 3 years and yearly epsilon was between 0.58 and 0.71 g C MJ(-1), which is high in comparison with other studies. There was a seasonal trend in epsilon with a relatively constant level of approximately 0.90 g C MJ(-1) from April to September Daily NPP did not increase for daily intercepted radiation above 6 MJ m(-2) d(-1), indicating that between-years variation in NPP is not directly dependent on total Q(i). The light was most efficiently used at an average daytime temperature of around 15 degreesC. At daytime vapour pressure deficit above 1400 Pa epsilon was reduced by approximately 50%.