Woodchips biochar versus bone char in a one-year model soil incubation experiment: the importance of soil/char pH alteration on nutrient availability in soil

BACKGROUND: Biochars have become one of the most intensively and extensively investigated soil amendment materials in terms of their production, application and fate in the soil because of benefits such as increased soil quality and fertility. Biochar from wood chips and bone char from meat bone waste from a poultry slaughterhouse were prepared at 300 and 500 degrees C and then thoroughly mixed with two soils (cambisol and luvisol) that differed in their physicochemical parameters in ratios of 2% and 5% (w/w).RESULTS: The impact of bone and biochar amendments on nutrient availability was assessed during a one-year model laboratory experiment. The feedstock origin and pyrolysis temperature affected the prepared materials' physical properties and nutrient (Ca, Cu, K, Mg, Mn, P, S, Zn) availability. With increasing temperature, the structure of woodchip biochar changed from macroporous to microporous, and bone char changed from non-porous to mesoporous. However, when mixed with soil, the biochar-derived change in soil pH was revealed to be the most crucial parameter affecting soil nutrient mobility. Of all the tested elements, Only Cu, Fe and Zn were unaffected by biochar addition. Furthermore, temporal changes in element mobility during incubation were also elucidated.CONCLUSION: The changes over time in element mobility indicated that soil properties were more important than bone and biochar characteristics.

Automated summary

This study compared the effects of woodchip biochar and bone char on soil nutrient balance and found that soil properties were more important than the characteristics of biochar and bone char in determining element mobility.