Institute of Environmental Science and Technology (ICTA), Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain.
Institute of Environmental Science and Technology (ICTA), Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain; Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA; Department of Earth System Science, Stanford University, Stanford, CA, USA.
Sci Total Environ. 2021 Mar 10;759:143535. doi: 10.1016/j.scitotenv.2020.143535. Epub 2020 Nov 5.
Secondary succession on abandoned agricultural lands can produce climate change mitigation co-benefits, such as soil carbon sequestration. However, the accumulation of soil organic carbon (SOC) in Mediterranean regions has been difficult to predict and is subject to multiple environmental and land management factors. Gains, losses, and no significant changes have all been reported. Here we compile chronosequence data (n = 113) from published studies and new field sites to assess the response of SOC to agricultural land abandonment in peninsular Spain. We found an overall SOC accumulation rate of +2.3% yr post-abandonment. SOC dynamics are highly variable and context-dependent. Minimal change occurs on abandoned cereal croplands compared to abandoned woody croplands (+4% yr). Accumulation is most prevalent within a Goldilocks climatic window of ~13-17 °C and ~450-900 mm precipitation, promoting >100% gains after three decades. Our secondary forest field sites accrued 40.8 Mg C ha (+172%) following abandonment and displayed greater SOC and N depth heterogeneity than natural forests demonstrating the long-lasting impact of agriculture. Although changes in regional climate and crop types abandoned will impact future carbon sequestration, abandonment remains a low-cost, long-term natural climate solution best incorporated in tandem with other multipurpose sustainable land management strategies.
废弃农业土地上的次生演替可以带来气候变化缓解的共同效益，例如土壤碳固存。然而，地中海地区土壤有机碳 (SOC) 的积累一直难以预测，并且受到多种环境和土地管理因素的影响。报告称 SOC 既有增加、减少，也有无显著变化。在这里，我们汇集了来自已发表研究和新野外站点的时间序列数据（n = 113），以评估 SOC 对西班牙半岛废弃农业土地的响应。我们发现，废弃后 SOC 的总体积累率为+2.3% yr。SOC 动态高度可变且依赖于背景。与废弃木本作物相比，废弃谷类作物的变化最小（+4% yr）。在13-17°C 和450-900 mm 降水的“金发姑娘气候窗口”内，积累最为普遍，在 30 年内增加了>100%。我们的次生林野外站点废弃后积累了 40.8 Mg C ha（+172%），SOC 和 N 深度异质性大于天然林，表明农业具有长期影响。尽管废弃的区域气候和作物类型的变化将影响未来的碳固存，但废弃仍然是一种低成本、长期的自然气候解决方案，最好与其他多用途可持续土地管理策略同时采用。
