Cotrufo M F, Ineson P
Division of Biological Sciences, Institute of Environmental and Biological Sciences, Lancaster University, LA1 4YQ, Lancaster, UK.
Merlewood Research Station, Institute of Terrestrial Ecology, LA11 6JU, Grange-over-Sands, Cumbria, UK.
Oecologia. 1996 Jun;106(4):525-530. doi: 10.1007/BF00329711.
The effect of elevated atmospheric CO and nutrient supply on elemental composition and decomposition rates of tree leaf litter was studied using litters derived from birch (Betula pendula Roth.) plants grown under two levels of atmospheric CO (ambient and ambient +250 ppm) and two nutrient regimes in solar domes. CO and nutrient treatments affected the chemical composition of leaves, both independently and interactively. The elevated CO and unfertilized soil regime significantly enhanced lignin/N and C/N ratios of birch leaves. Decomposition was studied using field litter-bags, and marked differences were observed in the decomposition rates of litters derived from the two treatments, with the highest weight remaining being associated with litter derived from the enhanced CO and unfertilized regime. Highly significant correlations were shown between birch litter decomposition rates and lignin/N and C/N ratios. It can be concluded, from this study, that at levels of atmospheric CO predicted for the middle of the next century a deterioration of litter quality will result in decreased decomposition rates, leading to reduction of nutrient mineralization and increased C storage in forest ecosystems. However, such conclusions are difficult to generalize, since tree responses to elevated CO depend on soil nutritional status.
利用在两个大气CO₂水平（环境水平和环境水平+250 ppm）以及日光温室中的两种养分状况下生长的桦树（垂枝桦）的凋落物，研究了大气CO₂浓度升高和养分供应对树叶凋落物元素组成和分解速率的影响。CO₂和养分处理分别及交互地影响了树叶的化学成分。CO₂浓度升高和未施肥的土壤状况显著提高了桦树叶的木质素/氮和碳/氮比率。使用田间凋落物袋研究了分解情况，观察到两种处理的凋落物在分解速率上存在显著差异，剩余重量最高的与来自CO₂浓度升高和未施肥状况的凋落物相关。桦树凋落物分解速率与木质素/氮和碳/氮比率之间呈现高度显著的相关性。从这项研究可以得出结论，在下个世纪中叶预测的大气CO₂水平下，凋落物质量的恶化将导致分解速率降低，从而导致森林生态系统中养分矿化减少和碳储存增加。然而，由于树木对CO₂浓度升高的反应取决于土壤营养状况，这些结论很难一概而论。
