Biochar Yield and Quality Enhancement by Poultry Manure Spiking at Varied Slow Pyrolysis Heating Regimes

Harnessing the high macronutrient in poultry manure (PM) for enhanced biochar yield (BY) and quality through blending with Gmelina arborea sawdust (SD) or Tithonia diversifolia shoot (TD) at slow pyrolysis (350 °C) heating regimes (HRs) was the focus of this work. Twelve biochars were produced from SD and TD with or without PM at three slow pyrolysis HRs of 5, 10 and 20 minutes in completely randomized design with three replications. Dominant biochar parameters contributing to BY and ash content were reported. Results indicated PM spiking and HR significantly (p < 0.001) improved BY and nutrient quality irrespective of plant biomass type. The BY increased by 107% (5 min HR) and 79% (10 min HR) with PM spiking while ash content increased with increasing HR by 599 and 305% following PM spiking in TD and SD respectively. 20 and 10 minute HRs enhanced N and P contents in SD and TD biochar respectively. PM spiking and increasing HR from 10 to 20 minutes reduced biochar organic C by 159% in TD biochar. Reduced organic C, C/N and C/P dominantly influenced BY and ash content. PM when appropriately bulked with SD and TD produces higher BY and quality under slow pyrolysis condition.