Bang-Andreasen Toke, Nielsen Jeppe T, Voriskova Jana, Heise Janine, Rønn Regin, Kjøller Rasmus, Hansen Hans C B, Jacobsen Carsten S
Department of Environmental Science, Aarhus UniversityRoskilde, Denmark.
Department of Biology, University of CopenhagenCopenhagen, Denmark.
Front Microbiol. 2017 Jul 28;8:1400. doi: 10.3389/fmicb.2017.01400. eCollection 2017.
Recirculation of wood ash from energy production to forest soil improves the sustainability of this energy production form as recycled wood ash contains nutrients that otherwise would be lost at harvest. In addition, wood-ash is beneficial to many soils due to its inherent acid-neutralizing capabilities. However, wood ash has several ecosystem-perturbing effects like increased soil pH and pore water electrical conductivity both known to strongly impact soil bacterial numbers and community composition. Studies investigating soil bacterial community responses to wood ash application remain sparse and the available results are ambiguous and remain at a general taxonomic level. Here we investigate the response of bacterial communities in a spruce forest soil to wood ash addition corresponding to 0, 5, 22, and 167 t wood ash ha. We used culture-based enumerations of general bacteria, and sporeforming bacteria combined with 16S rRNA gene amplicon sequencing to valuate soil bacterial responses to wood ash application. Results showed that wood ash addition strongly increased soil pH and electrical conductivity. Soil pH increased from acidic through neutral at 22 t ha to alkaline at 167 t ha. Bacterial numbers significantly increased up to a wood ash dose of 22 t ha followed by significant decrease at 167 t ha wood ash. The soil bacterial community composition changed after wood ash application with copiotrophic bacteria responding positively up to a wood ash dose of 22 t ha while the adverse effect was seen for oligotrophic bacteria. Marked changes in bacterial community composition occurred at a wood ash dose of 167 t ha with a single alkaliphilic genus dominating. Additionally, spore-formers became abundant at an ash dose of 167 t ha whereas this was not the case at lower ash doses. Lastly, bacterial richness and diversity strongly decreased with increasing amount of wood ash applied. All of the observed bacterial responses can be directly explained by the wood ash induced changes in pH, electrical conductivity and the addition of wood ash inherent nutrients.
将能源生产过程中产生的木灰再循环至森林土壤，可提高这种能源生产形式的可持续性，因为回收的木灰含有养分，否则这些养分在收获时就会流失。此外，木灰因其固有的酸碱中和能力而对许多土壤有益。然而，木灰具有多种扰乱生态系统的效应，如土壤pH值升高和孔隙水电导率增加，这两者都已知会强烈影响土壤细菌数量和群落组成。研究土壤细菌群落对木灰施用的反应的研究仍然很少，现有结果不明确，且仍停留在一般分类水平。在此，我们研究了云杉林土壤中细菌群落对分别相当于0、5、22和167吨木灰/公顷的木灰添加量的反应。我们使用基于培养的方法对一般细菌和产芽孢细菌进行计数，并结合16S rRNA基因扩增子测序来评估土壤细菌对木灰施用的反应。结果表明，添加木灰会显著提高土壤pH值和电导率。土壤pH值从酸性（22吨/公顷时为中性）升高到167吨/公顷时为碱性。细菌数量在木灰剂量达到22吨/公顷之前显著增加，随后在167吨/公顷木灰时显著减少。施用木灰后土壤细菌群落组成发生变化，富营养型细菌在木灰剂量达到22吨/公顷之前呈正向反应，而贫营养型细菌则受到不利影响。在167吨/公顷的木灰剂量下，细菌群落组成发生显著变化，单个嗜碱菌属占主导地位。此外，在167吨/公顷的灰分剂量下产芽孢菌变得丰富，而在较低灰分剂量下则不然。最后，细菌丰富度和多样性随着木灰施用量的增加而强烈下降。所有观察到的细菌反应都可以直接由木灰引起的pH值、电导率变化以及木灰固有养分的添加来解释。
