Eze Samuel, Magilton Matthew, Magnone Daniel, Varga Sandra, Gould Iain, Mercer Theresa G, Goddard Matthew R
Department of Life Sciences, School of Life and Environmental Sciences, University of Lincoln, LN6 7DL Lincoln, UK.
Department of Life Sciences, School of Life and Environmental Sciences, University of Lincoln, LN6 7DL Lincoln, UK.
Sci Total Environ. 2023 Feb 20;860:160484. doi: 10.1016/j.scitotenv.2022.160484. Epub 2022 Nov 25.
The restoration of degraded lands and minimizing the degradation of productive lands are at the forefront of many environmental land management schemes around the world. A key indicator of soil productivity is soil organic carbon (SOC), which influences the provision of most soil ecosystem services. A major challenge in direct measurement of changes in SOC stock is that it is difficult to detect within a short timeframe relevant to land managers. In this study, we sought to identify suitable early indicators of changes in SOC stock and their drivers. A meta-analytical approach was used to synthesize global data on the impacts of arable land conversion to other uses on total SOC stock, 12 different SOC fractions and three soil structural properties. The conversion of arable lands to forests and grasslands accounted for 91 % of the available land use change datasets used for the meta-analysis and were mostly from Asia and Europe. Land use change from arable lands led to 50 % (32-68 %) mean increase in both labile (microbial biomass C and particulate organic C - POC) and passive (microaggregate, 53-250 μm diameter; and small macroaggregate, 250-2000 μm diameter) SOC fractions as well as soil structural stability. There was also 37 % (24-50 %) mean increase in total SOC stock in the experimental fields where the various SOC fractions were measured. Only the POC and the organic carbon stored in small macroaggregates had strong correlation with total SOC: our findings reveal these two SOC fractions were predominantly controlled by biomass input to the soil rather than climatic factors and are thus suitable candidate indicators of short-term changes in total SOC stock. Further field studies are recommended to validate the predictive power of the equations we developed in this study and the use of the SOC metrics under different land use change scenarios.
退化土地的恢复以及尽量减少生产性土地的退化，是全球许多环境土地管理计划的首要任务。土壤有机碳（SOC）是土壤生产力的一个关键指标，它影响着大多数土壤生态系统服务的提供。直接测量SOC储量变化的一个主要挑战是，在与土地管理者相关的短时间内很难检测到。在本研究中，我们试图确定合适的SOC储量变化早期指标及其驱动因素。采用元分析方法综合全球关于耕地转为其他用途对总SOC储量、12种不同SOC组分和三种土壤结构特性影响的数据。耕地转为森林和草地占用于元分析的可用土地利用变化数据集的91%，且大多来自亚洲和欧洲。耕地的土地利用变化导致不稳定（微生物生物量碳和颗粒有机碳 - POC）和被动（微团聚体，直径53 - 250μm；以及小宏团聚体，直径250 - 2000μm）SOC组分以及土壤结构稳定性平均增加50%（32 - 68%）。在测量了各种SOC组分的试验田中，总SOC储量也平均增加了37%（24 - 50%）。只有POC和储存在小宏团聚体中的有机碳与总SOC有很强的相关性：我们的研究结果表明，这两种SOC组分主要受土壤生物量输入控制，而非气候因素，因此是总SOC储量短期变化的合适候选指标。建议进一步开展田间研究，以验证我们在本研究中开发的方程的预测能力以及在不同土地利用变化情景下SOC指标的使用。
