Two phosphorus (P)-rich biowastes, sewage sludge (SS) and bone dreg (BD), were selected to clarify P footprints among biowaste, biochar, soil, and plants by introducing a novel " 3R " concept model. Results showed that pyrolysis resulted in P transformation from an unstable-organic amorphous phase to a stable-inorganic crystalline phase with a P retention rate of 70-90% in biochar ( P reservation ). In soil, SSBC released more P in acid red soil and alkaline yellow soil than BDBC, while the opposite result appeared in neutral paddy soil. The P released from SSBC formed AlPO 4 by combining with Al in soil, whereas P from BDBC transformed into Ca 5 (PO 4 ) 3 F(or Cl) in conjunction with Ca in the soil ( P replenishment ). Various plants exhibited an uptake of approximately 2-6 times more P from biochar-amended soil than from the original soil ( P reception ). This study can guide the application of biochar in various soil-plant systems for effective nutrient reclamation.