Results from the first ever scientific study of biochar by researchers at the University of Southampton have been released. Plant growth was stimulated (up to 100%!) but,
the positive impacts of biochar were coupled with negative findings for a suite of genes that are known to determine the ability of a plant to withstand attack from pests and pathogens. These defence genes were consistently reduced following biochar application to the soil, for example jasmonic and salcyclic acid and ethylene, suggesting that crops grown on biochar may be more susceptible to attack by pests and pathogens. This was a surprising finding and suggests that if reproduced in the field at larger scales, could have wide implications for the use of biochar on commercial crops.
The researchers concluded:
Our findings provide the very first insight into how biochar stimulates plant growth — we now know that cell expansion is stimulated in roots and leaves alike and this appears to be the consequence of a complex signalling network that is focused around two plant growth hormones. However, the finding for plant defense genes was entirely unpredicted and could have serious consequences for the commercial development and deployment of biochar in future. Any risk to agriculture is likely to prevent wide scale use of biochar and we now need to see which pest and pathogens are sensitive to the gene expression changes.
Thanks to Michael Tortorello for the tip.