Changes in phosphorus fractions in three tropical soils amended with corn cob and rice husk biochars |
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| Authors: | Joseph Osafo Eduah Mark Kofi Abekoe Mathias Neumann Andersen |
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| Institution: | 1. Department of Soil Science, School of Agriculture, University of Ghana , Legon, Ghana;2. Department of Geosciences and Natural Resource Management, University of Copenhagen , Copenhagen, Denmark;3. Department of Soil Science, School of Agriculture, University of Ghana , Legon, Ghana;4. Department of Agroecology and Environment, Aarhus University , Aarhus, Denmark |
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| Abstract: | 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. |
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| Keywords: | Corn cob biochar phosphorus fractions pyrolysis temperature rice husk biochar soil |
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