Plant community mediated vs. nutritional controls on litter decomposition rates in grasslands
Plant community mediated vs. nutritional controls on litter decomposition rates in grasslands
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DOI：
10.1890/02-0712
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发表时间：
2003-12-01
期刊：
影响因子：
4.8
通讯作者：
Beltman, B
中科院分区：
文献类型：
--
作者：
Aerts, R;De Caluwe, H;Beltman, B
草地是地球上主要的生物群落之一，是重要的土壤碳汇。这些草地的养分富集可以通过分解过程对碳损失产生重大影响。我们研究了长期（12年）实验增加N和/或P供应对凋落物生产和化学和分解的散装凋落物从两个草原不同的土壤养分status.Potential地上凋落物生产的控制中的P丰富的低生产力河岸草地低于在N丰富的高生产力泥炭草地，并增加与增强N供应。养分处理没有提高凋落物的生产力高的泥炭草地。以莎草科植物为主的泥炭草地凋落物中酚类物质含量是以草本植物为主的河岸草地的2-3倍。在这两个网站增加养分供应没有检测到酚类化合物浓度的影响。所有与磷相关的凋落物化学参数反映了河岸带草地土壤磷含量较高的状况。磷施肥有更大的影响凋落物化学在磷缺乏泥炭草地比在磷丰富的河岸草地。在这两个网站，有没有变化，整体凋落物化学响应N施肥，除了较高的木质素浓度的泥炭草原凋落物。短期（8周）在实验室和3年的垃圾袋在现场的研究表明，河岸草地凋落物分解速度比泥炭草原凋落物。长期养分添加对各草地类型凋落物分解无显著影响。对两个地点的综合数据的回归分析表明，酚类物质，在较小程度上，与P相关的凋落物化学参数，对凋落物呼吸和凋落物质量损失都有很强的控制作用。长期试验性养分添加不会导致草原分解速率的增加，初始植物群落凋落物质量是分解过程中碳损失的主要决定因素过程这项研究的结果表明，养分富集可能会影响生态系统的碳平衡，影响凋落物产生比影响凋落物分解速率。
Grasslands are one of the major biomes on earth and can serve as important soil carbon sinks. Nutrient enrichment of these grasslands can have a significant impact on carbon losses through the decomposition process. We investigated the effects of long-term (12-yr) experimentally increased N and/or P supply on litter production and on the chemistry and decomposition of bulk litter from two grasslands differing in soil nutrient status.Potential aboveground litter production in the controls of a P-rich low-productivity riparian grassland was lower than that in a N-rich high-productivity peat grassland and increased with enhanced N supply. Nutrient treatments did not enhance litter production in the high-productivity peat grassland. The concentrations of phenolics in bulk litter from the peat grassland, dominated by sedges, were 2-3 times higher than those in the riparian grassland that was dominated by herbs and grasses. At both sites increased nutrient supply had no detectable effect on phenolics concentrations. All P-related litter chemistry parameters reflected the higher soil P status of the riparian grassland. P fertilization had a greater effect on litter chemistry in the P-deficient peat grassland than in the P-rich riparian grassland. At both sites, there was no change in overall litter chemistry in response to N fertilization, except for higher lignin concentrations in the peat grassland litter. Both short-term (8 wk) litter incubations in the laboratory and a 3-yr litter bag study in the field showed that riparian grassland litter decomposed faster than litter from the peat grassland. The long-term nutrient additions had no significant effects on the decomposition of the bulk litter of each grassland type. Regression analysis on the combined data of the two sites showed that phenolics, and to a lesser extent, P-related litter chemistry parameters, exerted a strong control on both litter respiration and litter mass loss.Our study shows that long-term experimental nutrient additions do not lead to increased decomposition rates in grasslands and that the initial plant community litter quality is the main determinant of carbon losses through the decomposition process. The results of this study suggest that nutrient enrichment will likely affect ecosystem carbon balance more by affecting litter production than by affecting litter decomposition rates.