Department of Geography, Environmental Sciences Institute (IUCA), University of Zaragoza, Spain; Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, The Netherlands.
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, The Netherlands.
Sci Total Environ. 2016 Oct 1;566-567:741-752. doi: 10.1016/j.scitotenv.2016.05.031. Epub 2016 May 27.
The effects of land use changes on soil carbon stocks are a matter of concern stated in international policy agendas on the mitigation of greenhouse emissions. Afforestation is increasingly viewed as an environmental restorative land use change prescription and is considered one of the most efficient carbon sequestration strategies currently available. Given the large quantity of CO2 that soils release annually, it is important to understand disturbances in vegetation and soil resulting from land use changes. The main objective of this study is to assess the effects of land abandonment, land use change and afforestation practices on soil organic carbon (SOC) dynamics. For this aim, five different land covers (bare soil, permanent pastureland, secondary succession, Pinus sylvestris (PS) and Pinus nigra (PN) afforestation), in the Central Spanish Pyrenees, were analysed. SOC dynamics have been studied in the bulk soil, and in the fractions separated according to two methodologies: (i) aggregate size distribution, and (ii) density fractionation, and rates of carbon mineralization have been determined by measuring CO2 evolution using an automated respirometer. The results showed that: (i) SOC contents were higher in the PN sites in the topsoil (10cm), (ii) when all the profiles were considered no significant differences were observed between pastureland and PN, (iii) SOC accumulation under secondary succession is a slow process, and (iv) pastureland should also be considered due to the relative importance in SOC stocks. The first step of SOC stabilization after afforestation is the formation of macro-aggregates promoted by large inputs of SOC, with a high contribution of labile organic matter. However, our respiration experiments did not show evidence of SOC stabilization. SOC mineralization was higher in the top layers and values decreased with depth. These results gain insights into which type of land management is most appropriate after land abandonment for SOC.
土地利用变化对土壤碳储量的影响是国际温室气体减排政策议程关注的问题。造林越来越被视为一种环境恢复性土地利用变化的方法，被认为是目前最有效的碳封存策略之一。鉴于土壤每年释放的大量 CO2，了解土地利用变化导致的植被和土壤干扰非常重要。本研究的主要目的是评估土地废弃、土地利用变化和造林实践对土壤有机碳（SOC）动态的影响。为此，分析了西班牙中部比利牛斯山脉的五种不同土地覆盖（裸地、永久性牧场、次生演替、欧洲赤松（PS）和欧洲黑松（PN）造林）。SOC 动态在原状土壤和根据两种方法分离的分馏中进行了研究：（i）团聚体大小分布，和（ii）密度分馏，并通过使用自动呼吸计测量 CO2 释放来确定碳矿化速率。结果表明：（i）表层土壤（10cm）中 PN 地点的 SOC 含量较高，（ii）当考虑所有剖面时，牧场和 PN 之间没有观察到显著差异，（iii）次生演替下的 SOC 积累是一个缓慢的过程，（iv）由于 SOC 储量的相对重要性，牧场也应该被考虑。造林后 SOC 稳定的第一步是由大量 SOC 输入促进的大团聚体的形成，其中含有大量的易分解有机物。然而，我们的呼吸实验并没有表明 SOC 稳定的证据。SOC 矿化在上层较高，随深度降低。这些结果深入了解了土地废弃后哪种土地管理类型最适合 SOC。
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