State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, China.
Physical Geography and Environmental Change, Department of Environmental Sciences, University of Basel, Basel, Switzerland.
PLoS One. 2018 Jul 26;13(7):e0200901. doi: 10.1371/journal.pone.0200901. eCollection 2018.
Biomass as a renewable energy source has become increasingly prevalent in Europe to comply with greenhouse gas emission targets. As one of the most efficient perennial bioenergy crops, there is great potential in the Upper Rhine Region to explore biomass utilization of Miscanthus to confront climate change and land use demand in the future. Yet, the impacts of Miscanthus cultivation on soil quality have not been adequately explored. This study investigated the soil profiles of five- and 20-year-old Miscanthus fields (1 m depth) as well as grassland for reference in eastern France and Switzerland. The soil organic carbon (SOC) concentrations and δ13C compositions of four soil layers (0-10 cm, 10-40 cm, 40-70 cm and 70-100 cm) were determined. The CO2 emission rates of the topsoil were monitored for 42 days. Our results showed that Miscanthus, in general, could increase the SOC stocks compared to grassland, but the benefits of SOC sequestration were constrained to the surface soil. Isotopically, the Miscanthus-derived SOC ranged from 69% in the top 10 cm of soil down to only 7% in the 70 cm to 100 cm layer. This result raises the risk of overestimating the total net benefits of Miscanthus cultivation, when simply using the greater SOC stocks near the surface soil to represent the SOC-depleted deep soil layers. The Miscanthus fields had greater CO2 emissions, implying that the Miscanthus fields generated greater ecosystem respiration, rather than larger net ecosystem exchanges. Compared to the grassland soils, the surface soils of the Miscanthus fields tended to have a risk of acidification while having higher concentrations of phosphorus and potassium, calling for the inclusion of soil characteristics and SOC stability when evaluating the impacts of long-term Miscanthus cultivation on both current and future land use changes.
生物质作为一种可再生能源，在欧洲为了符合温室气体排放目标而变得越来越普遍。作为最有效的多年生生物能源作物之一，在上莱茵地区有很大的潜力可以探索利用柳枝稷来应对未来的气候变化和土地利用需求。然而，柳枝稷种植对土壤质量的影响尚未得到充分探讨。本研究调查了法国东部和瑞士的 5 年和 20 年生柳枝稷地（1 米深）以及草地的土壤剖面，以供参考。测定了四个土壤层（0-10 cm、10-40 cm、40-70 cm 和 70-100 cm）的土壤有机碳（SOC）浓度和 δ13C 组成。监测了表层土壤的 CO2 排放率 42 天。结果表明，与草地相比，柳枝稷通常可以增加 SOC 储量，但 SOC 固存的好处仅限于表层土壤。在同位素方面，柳枝稷衍生的 SOC 从表层土壤的 69%下降到 70-100 cm 层的仅 7%。这一结果增加了高估柳枝稷种植总净效益的风险，因为仅仅使用表层土壤中的较大 SOC 储量来代表 SOC 耗尽的深层土壤层。柳枝稷地的 CO2 排放量更大，这意味着柳枝稷地产生了更大的生态系统呼吸，而不是更大的净生态系统交换。与草地土壤相比，柳枝稷地的表层土壤往往有酸化的风险，同时磷和钾的浓度较高，这就要求在评估长期柳枝稷种植对当前和未来土地利用变化的影响时，包括土壤特性和 SOC 稳定性。
