Abstract Phosphate fixation is a main factor limiting phosphate availability and reducing crop production in acidic soils. Although biochar addition has been suggested as a means of ameliorating acidic soils, questions remain about the impacts of biochar on phosphate fixation and availability in these soils. To address these questions, a biochar produced from sugarcane bagasse was added at four different levels (0, 1, 3, and 6% w/w) to an acidic soil. After 30 days of incubation, comparisons were made between the chemical properties of the biochar-amended soils and those of the original one. Sorption isotherm experiments were also conducted to estimate soil phosphate sorption capacity and affinity parameters under biochar amendment. Results showed that biochar application improved such soil chemical properties as pH and cation exchange capacity as well as exchangeable calcium, magnesium, sodium, and potassium cations. Biochar was also observed to increase phosphate sorption capacity of the soil but reduce its phosphate sorption strength, indicating that biochar-amended soils were potentially able to fix lower amounts of phosphate than the original acidic soil was. Moreover, soil phosphate buffering capacity indices decreased as a result of biochar incorporation, indicating the easier release of phosphate from the solid to the solution phase in biochar-amended soils. Biochar addition was also observed to reduce effectively (up to 62%) the standard phosphorus requirement of the soil. In conclusion, biochar amendment was found to induce positive changes in phosphate sorption properties of acidic soils, thereby providing conditions more favorable to plant growth through sufficient phosphate availability.

中文翻译：

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使用生物炭作为减少酸性土壤磷酸盐固定和外部磷需求的可能手段

摘要 固磷是酸性土壤中限制磷酸盐可用性和减少作物产量的主要因素。尽管已建议添加生物炭作为改善酸性土壤的一种手段，但关于生物炭对这些土壤中磷酸盐固定和可用性的影响仍然存在问题。为了解决这些问题，将甘蔗渣生产的生物炭以四种不同的水平（0%、1%、3% 和 6% w/w）添加到酸性土壤中。培养 30 天后，对生物炭改良土壤的化学性质与原始土壤的化学性质进行了比较。还进行了吸附等温线实验以估计生物炭修正下的土壤磷酸盐吸附能力和亲和力参数。结果表明，施用生物炭改善了土壤化学性质，如 pH 值和阳离子交换能力以及可交换的钙、镁、钠和钾阳离子。还观察到生物炭会增加土壤的磷酸盐吸附能力，但会降低其磷酸盐吸附强度，表明生物炭改良的土壤可能比原始酸性土壤固定更少数量的磷酸盐。此外，由于生物炭的掺入，土壤磷酸盐缓冲能力指数降低，表明在生物炭改良的土壤中，磷酸盐更容易从固相释放到溶液相。还观察到添加生物炭可有效降低（最多 62%）土壤的标准磷需求量。综上所述，