Biochar Yield Boost Comes at Pest and Disease Risk

Photo by Ischaramoochie. (CC BY-SA 3.0)

Today, Root Simple blogger "Mr. Homegrown" posted about new research done by European scientists on the effects of using biochar as a soil additive, something I found timely after my post last week. The study measured yield and gene expression in two test crops, thale cress and lettuce. While crop yields increased by up to 100%, the plants produced fewer chemicals that protect them from pests and disease – a worrisome risk.

However, 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.

A lead researcher, Professor Gail Taylor, Director of Research at the University of Southampton's Centre for Biological Sciences, commented:

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 focussed around two plant growth hormones. However, the finding for plant defence 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.

I doubt this is the end of the story. There will be more scientific research. But I think that it does show that biochar, while beneficial as a soil amendment for producing rich croplands while sequestering carbon, is not a panacea, especially at industrial scale. I doubt there are any simple, industrial scale solutions to Global Warming, just thousands of small changes that need to be made.

#biochar #agriculture #permaculture #globalwarming #soil