Abstract：
Biochar has been recognized as a promising practice for ameliorating degraded soils, yet the consensus on its effects remains largely unknown due to the variability among biochar, soil and plant. This study therefore presents a meta-analysis synthesizing 92 publications containing 987 paired data to scrutinize biochar effects on salt-affected soil properties and plant productivity. Additionally, a random meta-forest approach was employed to identify the key factors of biochar on salt-affected soil and plant productivity. Results showed that biochar led to significant reductions in electrical conductivity (EC), bulk density (BD) and pH by 7.4%, 4.7% and 1.2% compared to the unamended soil, respectively. Soil organic carbon (by 55.1%) and total nitrogen (by 31.3%) increased significantly with biochar addition. Moreover, biochar overall enhanced plant productivity by 31.5%, and more pronounced increases in forage/medicinal with higher salt tolerance than others. The results also identified that the soil salinity and biochar application rate were the most important co-regulators for EC and PP changes. The structural equation model further showed that soil salinity (P < 0.001), biochar pH (P < 0.001) and biochar specific surface area (P < 0.01) had a significant negative effect on soil EC, but it was positively impacted by biochar pyrolysis temperature (P < 0.05). Furthermore, plant productivity was positively affected by biochar pH (P < 0.001) and biochar feedstock (P < 0.01), while negatively influenced by biochar pyrolysis temperature (P < 0.01). This study highlights that woody biochar with 7.6 < pH < 9.0 and pyrolyzed at 400-600 °C under 30-70 t ha-1 application rate in moderately saline coarse soils is a recommendable pattern to enhance forage/medicinal productivity while reducing soil salinity. In conclusion, biochar offers promising avenues for ameliorating degradable soils, but it is imperative to explore largescale applications and field performance across different biochar, soil, and plant types.
摘要：
生物炭被认为是改善退化土壤的一种有前途的做法，然而，由于生物炭之间的可变性，对其影响的共识在很大程度上仍然未知，土壤和植物。因此，这项研究提出了一项荟萃分析，综合了92份出版物，其中包含987份配对数据，以审查生物炭对盐影响的土壤特性和植物生产力的影响。此外,采用随机元森林方法来确定生物炭对盐影响土壤和植物生产力的关键因素。结果表明，生物炭导致电导率(EC)显著降低，堆积密度(BD)和pH值降低7.4%，与未改良土壤相比，分别为4.7%和1.2%，分别。添加生物炭后，土壤有机碳（55.1％）和总氮（31.3％）显着增加。此外，生物炭整体提高植物生产力31.5%，牧草/药用的增加更明显，耐盐性比其他更高。结果还确定，土壤盐分和生物炭施用率是EC和PP变化的最重要的共调节剂。结构方程模型进一步表明,土壤盐分(P<0.001),生物炭pH值(P<0.001)和生物炭比表面积(P<0.01)对土壤EC,但受生物炭热解温度的影响较大(P<0.05)。此外，植物生产力受生物炭pH值(P<0.001)和生物炭原料(P<0.01)的影响，同时受生物炭热解温度的影响(P<0.01)。这项研究强调，在中度盐渍粗土中，在30-70tha-1的施用量下，7.6
