Urban biochar improves nitrogen and phosphorus availability in growing media

Abstract

The purpose of this study was to substitute sphagnum peat from plant growing media with urban biochar (UB) and evaluate its impact on nitrogen (N) and phosphorus (P) availability. The UB was produced from the pyrolysis (650°C) of a 2: 1 ratio of biosolids to green waste. We compared three mixes-20% sphagnum peat mixed with composted pine bark (B0), 20% UB mixed with composted pine bark (B20) and 60% UB mixed with composted pine bark (B60)-for their ability to promote plant growth and minimise leaching losses in a greenhouse experiment using silverbeet (Beta vulgaris ssp. cicla). Plants were grown in 4.0-L custom-made chambers with the capacity to collect leachate and measure nitrous oxide ga..