370-9 Land Application of Biochar and Phosphorus Retention: "an Inconvenient Truth".
See more from this Division: SSSA Division: Soils and Environmental Quality
See more from this Session: Soils and Environmental Quality Oral II
Wednesday, November 9, 2016: 10:20 AM
Phoenix Convention Center North, Room 126C
Abstract:
The paradox of biochar with high cation exchange capacity and at its ability to adsorb phosphorus (P) at the same time has puzzled scientists. Our research has shown that: i) biochars can constitute a P source when applied to minimally P-impacted sandy soils, and ii) biochar- enhanced P sorption at elevated solution concentrations may be reversible as concentrations revert to background levels. X-ray diffraction analysis did not identify any newly formed crystalline phase in wood-based, poultry litter or biosolids biochars of our studies, though the poultry litter biochar contained a P mineral (Whitlockite, beta-tricalcium phosphate, with or without Mg), a slow P release form. The solution phase in a biochar-soil environment contains Ca, Mg and Fe further indicating that any association of biochar-P with these metals is not stable. Soil, rather than biochar properties dictate environmentally sound P loading rates; the soil P storage capacity (SPSC) could be used as a tool to evaluate “safe” biochar applications at a given site.
See more from this Division: SSSA Division: Soils and Environmental Quality
See more from this Session: Soils and Environmental Quality Oral II