Miscanthus x giganteus leaf senescence, decomposition and C and N inputs to soil
Miscanthus x giganteus leaf senescence, decomposition and C and N inputs to soil
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DOI：
10.1111/j.1757-1707.2012.01192.x
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发表时间：
2012-11-01
影响因子：
5.6
通讯作者：
Recous, Sylvie
中科院分区：
文献类型：
--
作者：
Amougou, Norbert;Bertrand, Isabelle;Recous, Sylvie
能源作物目前被宣传为潜在的替代能源，有助于缓解温室气体（GHG）引起的气候变化。多年生作物芒草因其在低投入条件下生物质生产的巨大潜力而被认为是有前途的。然而，为了评估其温室气体减排潜力，需要更好地量化作物在各种管理系统下对土壤有机物回收的贡献。这项工作的目的是研究芒草种植园中脱落的叶子对碳 (C) 和氮 (N) 循环的影响。在法国北部的田间条件下，对衰老叶落的动态、叶子分解率（使用垃圾袋方法）和土壤表面的叶子积累进行了两个为期一年的跟踪。落叶平均每年输入 1.40 Mg C ha-1 和 16 kg N ha-1。由于分解，脱落的叶子在一年内损失了大约 54% 的初始质量；种植后 5 年，作为覆盖层积累在土壤表面的剩余质量相当于 7 毫克干物质 (DM) ha-1。根据估计的年叶碳回收率和添加碳的 35% 的稳定率，在芒草作物的 20 年寿命中，衰老叶对土壤碳的年贡献估计约为 0.50 Mg C ha-1yr-1 或 10 Mg C ha-1 总量。这一发现表明，对于芒草来说，脱落的叶子比根茎或根对土壤碳积累的贡献更大。相比之下，叶子氮向土壤的再循环少于其他氮通量，特别是涉及氮从植物顶部转移到根茎的氮通量。
Energy crops are currently promoted as potential sources of alternative energy that can help mitigate the climate change caused by greenhouse gases (GHGs). The perennial crop Miscanthus x giganteus is considered promising due to its high potential for biomass production under conditions of low input. However, to assess its potential for GHG mitigation, a better quantification of the crop's contribution to soil organic matter recycling under various management systems is needed. The aim of this work was to study the effect of abscised leaves on carbon (C) and nitrogen (N) recycling in a Miscanthus plantation. The dynamics of senescent leaf fall, the rate of leaf decomposition (using a litter bag approach) and the leaf accumulation at the soil surface were tracked over two 1-year periods under field conditions in Northern France. The fallen leaves represented an average yearly input of 1.40 Mg C ha-1 and 16 kg N ha-1. The abscised leaves lost approximately 54% of their initial mass in 1 year due to decomposition; the remaining mass, accumulated as a mulch layer at the soil surface, was equivalent to 7 Mg dry matter (DM) ha-1 5 years after planting. Based on the estimated annual leaf-C recycling rate and a stabilization rate of 35% of the added C, the annual contribution of the senescent leaves to the soil C was estimated to be approximately 0.50 Mg C ha-1yr-1 or 10 Mg C ha-1 total over the 20-year lifespan of a Miscanthus crop. This finding suggested that for Miscanthus, the abscised leaves contribute more to the soil C accumulation than do the rhizomes or roots. In contrast, the recycling of the leaf N to the soil was less than for the other N fluxes, particularly for those involving the transfer of N from the tops of the plant to the rhizome.