Common Ivy (Hedera helix L.) Derived Biochar's Potential as a Substrate Amendment: Effects of Leached Nutrients on Arabidopsis thaliana Plant Development

Abstract

Common ivy, Hedera helix L., could be a potential feedstock for biochar production based on its physicochemical characterization. However, this has not been supported by plant-growth experiments yet. Therefore, this study aims to provide insight into possible correlations between common ivy biochar's physicochemical characteristics and plant development, for the first time. Lab-scale 96-well plant growth experiments were performed on Arabidopsis thaliana seedlings, using common-ivy based biochars produced at 400 and 700 degrees C and with and without valuable compound extraction before pyrolysis. Potassium leaching from the biochars caused the growth medium's pH and conductivity to increase significantly after 7 cultivation days. This leaching caused the plants to express initial growth stress responses (Pearson = 0.930), which was proven by changes in their cell cycle regulation. Further cultivation, 7-10 days, showed total recovery of the seedlings subjected to biochars produced at 400 degrees C. Moreover, significant increases in plant fresh weight were established at 1% biochar concentration. Besides that, biochars produced at 700 degrees C did not significantly affect plant development compared to the control group due to the decreased phosphate availability of the growth medium. In conclusion, low-temperature (400 degrees C) outperform high-temperature (700 degrees C) biochars, and valuable compound extraction before pyrolysis does not impact the biochar performance.