Biochar is considered to enhance numerous soil ecosystem services, but whether it alleviates soil compaction is not well known. This paper: 1) synthesizes the biochar impacts on soil compaction parameters including bulk density, penetration resistance, aggregate tensile strength, Proctor maximum bulk density (soil compactability), and the water content at which the Proctor maximum bulk density occurs (critical water content), 2) discusses potential factors affecting biochar performance, and 3) compares the impacts of biochar on soil compaction with those of other amendments. Literature indicates that biochar generally reduces bulk density, tensile strength, and Proctor maximum bulk density; and increases the critical water content but may or may not reduce penetration resistance. Biochar reduces bulk density from −1% to −20% (-8.8% average), tensile strength from −8 to −72% (-31% average), and Proctor maximum bulk density from −1 to −19% (-9.3% average), whereas it increases the critical water content from 1 to 64% (21% average). The increase in critical water content suggests soils with biochar can be trafficked at higher water content without causing compaction than soils without biochar. An increase in biochar application rate reduces soil compaction and explains 11% to 63% of the variability in compaction parameters, but biochar benefits can be short-lived (<2 yr). It appears that, in general, at least 10 Mg ha⁻¹ of biochar are needed to significantly reduce compaction. Larger application rates (>20 Mg ha⁻¹) can be needed for reducing penetration resistance and Proctor maximum bulk density than for other compaction parameters. Biochar has similar benefits to manure for reducing soil bulk density and can complement other organic amendments for reducing soil compaction. How biochar feedstock, pyrolysis temperature; and companion amendments; and soil texture influence biochar impacts on compaction is still unclear. Overall, biochar has the potential to alleviate soil compaction, but more long-term field data, particularly on penetration resistance, Proctor maximum bulk density, and critical water content for multiple biochar application rates, feedstocks, pyrolysis temperature; and amendments are needed to better elucidate biochar effects, biochar longevity, and optimum levels of biochar application.

生物炭被认为可以增强许多土壤生态系统服务，但它是否减轻土壤板结尚不清楚。本文：1) 综合了生物炭对土壤压实参数的影响，包括容重、渗透阻力、集料抗拉强度、Proctor 最大容重（土壤压实性）和 Proctor 最大容重发生时的含水量（临界含水量） , 2) 讨论影响生物炭性能的潜在因素，以及 3) 比较生物炭与其他改良剂对土壤压实的影响。文献表明，生物炭通常会降低堆积密度、拉伸强度和 Proctor 最大堆积密度；并增加临界含水量，但可能会或可能不会降低渗透阻力。Biochar 将体积密度从 -1% 降低到 -20%（平均 -8.8%），拉伸强度从 -8% 到 -72%（平均 -31%），Proctor 最大堆积密度从 -1% 到 -19%（平均 -9.3%），而它将临界水含量从 1% 增加到 64%（21%）平均）。临界含水量的增加表明，与不含生物炭的土壤相比，含有生物炭的土壤可以在更高的含水量下运输而不会造成压实。生物炭施用率的增加减少了土壤压实，并解释了压实参数变化的 11% 至 63%，但生物炭的好处可能是短暂的（<2 年）。看来，一般来说，至少 10 毫克公顷 临界含水量的增加表明，与不含生物炭的土壤相比，含有生物炭的土壤可以在更高的含水量下运输而不会造成压实。生物炭施用率的增加减少了土壤压实，并解释了压实参数变化的 11% 至 63%，但生物炭的好处可能是短暂的（<2 年）。看来，一般来说，至少 10 毫克公顷 临界含水量的增加表明，与不含生物炭的土壤相比，含有生物炭的土壤可以在更高的含水量下运输而不会造成压实。生物炭施用率的增加减少了土壤压实，并解释了压实参数变化的 11% 至 63%，但生物炭的好处可能是短暂的（<2 年）。看来，一般来说，至少 10 毫克公顷^-1 biochar 需要显着减少压实。更大的施用率（>20 Mg ha ^-1) 与其他压实参数相比，可能需要降低穿透阻力和 Proctor 最大堆积密度。生物炭在降低土壤容重方面具有与粪肥相似的好处，并且可以补充其他有机改良剂以减少土壤板结。生物炭原料、热解温度如何；和配套修正案；和土壤质地影响 biochar 对压实的影响尚不清楚。总体而言，生物炭具有缓解土壤压实的潜力，但需要更多长期现场数据，特别是在渗透阻力、Proctor 最大堆积密度和多种生物炭施用率、原料、热解温度的临界含水量方面；需要进行修正以更好地阐明生物炭的影响、生物炭的寿命和生物炭应用的最佳水平。