Mixed afforestation of young subtropical trees promotes nitrogen acquisition and retention
Mixed afforestation of young subtropical trees promotes nitrogen acquisition and retention
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DOI：
10.1111/1365-2664.12157
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发表时间：
2014-02-01
影响因子：
5.7
通讯作者：
Haerdtle, Werner
中科院分区：
文献类型：
--
作者：
Lang, Anne C.;von Oheimb, Goddert;Haerdtle, Werner
全球范围内的植树造林活动不断增加，不仅可以生产木材和纸浆木材，还可以增强碳封存、养分保留或地下水补给等生态系统服务。在中国，已经并将大面积造林，以补偿以前砍伐的负面影响，并利用与造林相关的生态系统服务。为了进一步优化这些关于平衡养分（特别是氮）循环的服务，重要的是要了解造林项目中使用本地树种的混合物与目前建立的大规模单一栽培相比是否促进氮的获取和保留。为了测试物种丰富度对系统氮保留和树苗氮吸收的影响，我们在幼树人工林中进行了N-15示踪剂实验。为此，四种丰富的早期演替树种的树苗被种植在单一栽培、两种和四种混合物以及单树中。由于树苗生物量中氮库的增强，氮保留随着物种丰富度的增加而增加。这些物种丰富度效应随着时间的推移而增强。随着时间的推移，N-15 回收率的物种特异性差异揭示了氮吸收方面的地下生态位差异，这可能导致共存物种之间的资源利用互补。合成和应用。这项研究提供了混合造林促进幼苗期氮保留的证据。为了进一步改善与造林相关的生态系统服务，我们强烈建议使用本地树种的混合物而不是单一栽培。四种物质的混合物可以减少系统氮损失，从而可以减少由于氮淋滤造成的地下水污染。我们鼓励进一步调查，寻找最佳物种组合，促进与更封闭的养分循环和尽量减少土壤侵蚀相关的广泛生态系统服务。在我们的研究中，可以通过增加树种丰富度和选择最佳物种组合来优化人工林的氮保留能力。这项研究提供了混合造林从幼苗阶段就促进氮保留的证据。为了进一步改善与造林相关的生态系统服务，我们强烈建议使用本地树种的混合物而不是单一栽培。四种物质的混合物可以减少系统氮损失，从而可以减少由于氮淋滤造成的地下水污染。我们鼓励进一步调查，寻找最佳物种组合，促进与更封闭的养分循环和尽量减少土壤侵蚀相关的广泛生态系统服务。在我们的研究中，可以通过增加树种丰富度和选择最佳树种组合来优化人工林保留氮的能力。
Afforestation is globally increasing to produce timber and pulp wood, but also to enhance ecosystem services such as carbon sequestration, nutrient retention or groundwater recharge. In China, large areas have been and will be afforested in order to compensate for the negative impacts of former clear-cuttings and to make use of the ecosystem services associated with afforestation. In order to further optimize these services with regard to balanced nutrient (particularly nitrogen) cycles, it is important to know whether the use of mixtures of native tree species in afforestation projects promotes the acquisition and retention of nitrogen compared with the currently established large-scale monocultures.To test the effect of species richness on system N retention and tree sapling N uptake, we conducted a N-15 tracer experiment in a young tree plantation. To this end, saplings of four abundant early successional tree species were planted in monocultures, in two- and four-species mixtures and as single trees.Nitrogen retention increased with higher species richness due to enhanced N pools in sapling biomass. These species richness effects strengthened over time.Species-specific differences in N-15 recoveries over time revealed below-ground niche differentiation with regard to N uptake, which is likely to result in complementary resource use among coexisting species.Synthesis and applications. This study provides evidence that mixed afforestation promotes N retention from the sapling stage. To further improve ecosystem services associated with afforestation, we strongly suggest the use of mixtures of native tree species instead of monocultures. Mixtures of four species may reduce system N losses and thus may lessen groundwater contamination due to N leaching. We encourage further investigations to find optimal species combinations that promote a wide range of ecosystem services related to more closed nutrient cycles and minimized soil erosion. In our study, the plantations' capability to retain N could be optimized by means of both increasing tree species richness and by choosing the optimal species combinations.This study provides evidence that mixed afforestation promotes N retention from the sapling stage. To further improve ecosystem services associated with afforestation, we strongly suggest the use of mixtures of native tree species instead of monocultures. Mixtures of four species may reduce system N losses and thus may lessen groundwater contamination due to N leaching. We encourage further investigations to find optimal species combinations that promote a wide range of ecosystem services related to more closed nutrient cycles and minimized soil erosion. In our study, the plantations' capability to retain N could be optimized by means of both increasing tree species richness and by choosing the optimal species combinations.