Centre for Environmental and Marine Studies (CESAM), Department of Environment and Planning, University of Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro, Portugal.
Agriculture and Environment Department, Harper Adams University, Newport, Shropshire TF10 8NB, United Kingdom.
Sci Total Environ. 2023 May 1;871:161860. doi: 10.1016/j.scitotenv.2023.161860. Epub 2023 Feb 8.
Biochar application to soil has the potential to affect soil and vegetation properties that are key for the processes of runoff and soil erosion. However, both field and pot experiments show a vast range of effects, from strong reductions to strong increases in runoff and/or soil erosion. Therefore, this study aimed to quantify and interpret the impacts of biochar on runoff and soil erosion through the first systematic meta-analysis on this topic. The developed dataset consists of 184 pairwise observations for runoff and soil erosion from 30 independent studies but 8 of which just focused on soil erosion. Overall, biochar application to soil significantly reduced runoff by 25 % and erosion by 16 %. Mitigation of soil erosion in the tropics was approximately three times stronger (30 %) than at temperate latitudes (9 %); erosion reduction in the subtropical zone was 14 %, but not significantly different from either the tropical or temperate zones. Fewer reported field observations for runoff resulted in larger confidence intervals and only the temperate latitudes showed a significant effect (i.e. a 28 % reduction). At topsoil gravimetric biochar concentrations between 0.6 % and 2.5 %, significant reductions occurred in soil erosion, with no effect at lower and higher concentrations. Biochar experiments that included a vegetation cover reduced soil erosion more than twice as much as bare soil experiments, i.e. 27 % vs 12 %, respectively. This suggests that soil infiltration, canopy interception, and soil cohesion mechanisms may have synergistic effects. Soil amended with biochar pyrolyzed at >500 °C was associated with roughly double the erosion reduction than soil amended with biochar produced at 300-500 °C, which potentially could be related to the enhancement of hydrophobicity in the latter case. Our results demonstrate substantial potential for biochar to improve ecosystem services that are affected by increased infiltration and reduced erosion, while mechanistic understanding needs to be improved.
生物炭施用于土壤可能会影响到径流和土壤侵蚀过程中的关键土壤和植被特性。然而，无论是田间试验还是盆栽试验都表明，生物炭对径流和土壤侵蚀的影响范围很广，从强烈减少到强烈增加都有。因此，本研究旨在通过首次对该主题进行系统的荟萃分析，量化和解释生物炭对径流和土壤侵蚀的影响。所开发的数据集包括 30 项独立研究中关于径流和土壤侵蚀的 184 对观测值，但其中 8 项仅关注土壤侵蚀。总的来说，生物炭的施用使土壤的径流量减少了 25%，侵蚀量减少了 16%。在热带地区，生物炭对土壤侵蚀的缓解作用大约是在温带地区的三倍（30%）；亚热带地区的侵蚀减少了 14%，但与热带或温带地区没有显著差异。由于对径流的报道较少，置信区间较大，只有温带地区显示出显著的效果（即减少 28%）。在表土质量比为 0.6%至 2.5%的生物炭浓度范围内，土壤侵蚀显著减少，而在较低和较高浓度下没有影响。有植被覆盖的生物炭试验比裸土试验减少土壤侵蚀的效果大两倍，分别为 27%和 12%。这表明土壤入渗、冠层截留和土壤团聚体机制可能具有协同作用。与在 300-500°C 之间生产的生物炭相比，在 500°C 以上热解的生物炭对土壤侵蚀的减少作用大约增加了一倍，这可能与后者疏水性增强有关。我们的研究结果表明，生物炭具有很大的潜力，可以改善受入渗增加和侵蚀减少影响的生态系统服务，而机制理解需要进一步提高。
