Plant species richness promotes soil carbon and nitrogen stocks in grasslands without legumes
Plant species richness promotes soil carbon and nitrogen stocks in grasslands without legumes
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DOI：
10.1111/1365-2745.12280
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发表时间：
2014-09-01
影响因子：
5.5
通讯作者：
Hoffland, Ellis
中科院分区：
文献类型：
--
作者：
Cong, Wen-Feng;van Ruijven, Jasper;Hoffland, Ellis
1. 土壤碳、氮的储存是重要的生态系统功能。草地生物多样性试验表明，植物多样性对土壤碳氮储量有积极影响。然而，这些试验都包括豆类，豆类通过固氮构成重要的氮输入。事实上，这些实验结果表明，豆科植物对氮的固定是土壤碳氮储存的主要驱动因素。研究了在没有豆科植物的情况下，植物多样性对土壤碳氮储量的影响。在不含豆科植物的11年草地生物多样性试验中，测定了土壤碳氮储量。我们进一步测定了地上生物量生产力、立根生物量、土壤有机质分解和氮矿化率，以了解土壤碳氮储量变化与植物多样性的关系及其对植物生产力的反馈机制。结果表明，8种混交林的土壤碳和氮储量比同一种混交林的平均水平分别增加了18%和16%。土壤C和N储量的增加主要是由于植物生产力的提高导致的C输入和N滞留的增加，超过了分解导致的C损失的增加。重要的是，较高的土壤C和N储量与土壤N矿化率的提高有关，这可以解释在实验的最后几年观察到的正多样性-生产力关系的加强。合成。我们还证明，在没有豆科植物的情况下，植物物种丰富度通过提高植物生产力来促进土壤碳(C)和氮(N)储量。反过来，土壤碳氮储量的增加通过氮矿化的增强对植物生产力有正反馈作用，这可以进一步加速土壤碳氮的长期储存。
1. The storage of carbon (C) and nitrogen (N) in soil is important ecosystem functions. Grassland biodiversity experiments have shown a positive effect of plant diversity on soil C and N storage. However, these experiments all included legumes, which constitute an important N input through N-2-fixation. Indeed, the results of these experiments suggest that N-2 fixation by legumes is a major driver of soil C and N storage.2. We studied whether plant diversity affects soil C and N storage in the absence of legumes. In an 11-year grassland biodiversity experiment without legumes, we measured soil C and N stocks. We further determined above-ground biomass productivity, standing root biomass, soil organic matter decomposition and N mineralization rates to understand the mechanisms underlying the change in soil C and N stocks in relation to plant diversity and their feedbacks to plant productivity.3. We found that soil C and N stocks increased by 18% and 16% in eight-species mixtures compared to the average of monocultures of the same species, respectively. Increased soil C and N stocks were mainly driven by increased C input and N retention, resulting from enhanced plant productivity, which surpassed enhanced C loss from decomposition. Importantly, higher soil C and N stocks were associated with enhanced soil N mineralization rates, which can explain the strengthening of the positive diversity-productivity relationship observed in the last years of the experiment.4. Synthesis. We demonstrated that also in the absence of legumes, plant species richness promotes soil carbon (C) and nitrogen (N) stocks via increased plant productivity. In turn, enhanced soil C and N stocks showed a positive feedback to plant productivity via enhanced N mineralization, which could further accelerate soil C and N storage in the long term.