ABSTRACT The formation of phosphorus (P) compounds including iron-P, aluminum-P and calcium-P in highly weathered tropical soils can be altered upon biochar addition. We investigated the effect of corn cob biochar (CC) and rice husk biochar (RH) pyrolyzed at three temperatures (300°C, 450°C and 650°C) on phosphorus (P) fractions of three contrasting soils. A 90d incubation study was conducted by mixing biochar with soil at a rate of 1% w/w and at 70% field capacity. Sequential P fraction was performed on biochar, soil and soil-biochar mixtures. Increase in most labile P (resin-Pi, NaHCO3-Pi) and organic P fraction (NaHCO3-Po + NaOH-Po) in CC and RH biochars were inversely related to increasing temperature. HCl-Pi and residual P increased with increasing temperature. Interaction of CC and RH with soils resulted in an increase in most labile P as well as moderately labile P (NaOH-Pi) fractions in the soils. CC increased most labile P in the soils more than RH. The increase in most labile P fraction in soils was more significant at relatively lower temperatures (300°C and 450°C) than 650°C. However, the increase in HCl-Pi and residual P of the soils was more predominant at high temperature (650°C). The study suggested that biochar pyrolyzed at 300–450°C could be used to increase P bioavailability in tropical soils.

中文翻译：

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玉米芯和稻壳生物炭改良的三种热带土壤中磷含量的变化

摘要 添加生物炭可以改变高度风化的热带土壤中磷 (P) 化合物的形成，包括铁-P、铝-P 和钙-P。我们研究了在三种温度（300°C、450°C 和 650°C）下热解的玉米芯生物炭 (CC) 和稻壳生物炭 (RH) 对三种对比土壤的磷 (P) 部分的影响。通过将生物炭与土壤以 1% w/w 的比率和 70% 的田间容量混合进行 90 天的孵化研究。对生物炭、土壤和土壤-生物炭混合物进行连续 P 分数。CC 和 RH 生物炭中大多数不稳定 P（树脂-Pi、NaHCO3-Pi）和有机 P 部分（NaHCO3-Po + NaOH-Po）的增加与温度升高呈负相关。HCl-Pi 和残留 P 随温度升高而增加。CC 和 RH 与土壤的相互作用导致土壤中大多数不稳定磷和中等不稳定磷 (NaOH-Pi) 部分的增加。CC 比 RH 增加了土壤中的大部分不稳定磷。与 650°C 相比，在相对较低的温度（300°C 和 450°C）下，土壤中大多数不稳定磷比例的增加更为显着。然而，土壤中 HCl-Pi 和残留 P 的增加在高温（650°C）下更为显着。该研究表明，在 300-450°C 下热解的生物炭可用于提高热带土壤中磷的生物有效性。土壤中 HCl-Pi 和残留 P 的增加在高温（650°C）下更为显着。该研究表明，在 300-450°C 下热解的生物炭可用于提高热带土壤中磷的生物有效性。土壤中 HCl-Pi 和残留 P 的增加在高温（650°C）下更为显着。该研究表明，在 300-450°C 下热解的生物炭可用于提高热带土壤中磷的生物有效性。