This will be a poster presentation on biochar effects on substrate and plant response on a green roof substrate. Participants will learn the benefits of biochar amendment and its applications in erosion-prone fields, such as green roofs.
Full Presentation Abstract Green roofs have been suggested to provide ecosystem services in cities, but plant growth on rooftops is challenging due to the harsh environment. Biochar has recently been promoted as an ideal substrate additive on green roofs due to its light weight, high nutrient and water holding capacity, and recalcitrance. However, biochar is generally susceptible to water and wind erosion, which may result in biochar loss and environmental pollution. Amending biochar in granulated forms or as large particles may enhance biochar erosion resistance; however, research has not addressed this on green roof substrates. In this study, we compared properties of biochars processed with two distinct methods (conventional versus granulated biochars) at a wide particle size range (0.25 – 6.3 mm) and investigated their influences on green roof substrate properties and plant performance of the drought-tolerant forb Agastache foeniculum. We found that granulated biochars strongly improved plant growth and physiological performance, acting to neutralize pH and increase water retention capability of the substrate. In contrast, although conventional biochar enhanced substrate properties by reducing bulk density and increasing total porosity and water retention capacity, it suppressed plant performance. This is possibly due to the presence of mobile organic compounds, liming effects on an already alkaline substrate, and the high C:N ratio of the conventional biochar. In addition, our results show that granulated biochar at intermediate particle sizes best improved plant performance. Our results suggest that the applications of granulated biochar on green roofs, in addition to reducing biochar erosion, can enhance substrate property and plant performance.
Learning Objectives:
Learn about biochar and the reasons why apply biochar on green roofs.
Understand why and how post-processed biochars can mitigate biochar and substrate erosion loss, particularly on green roofs.
Understand how can biochar post-processing treatments influence biochar and substrate property and plant performance on a green roof substrate and what are other potential applications of our findings.
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