29 Mar 2023
An Agronomist's View on Enhanced Weathering - UNDO
Through enhanced weathering, we are committed to removing 1 billion tonnes of carbon dioxide by 2030. It’s an ambitious target and to achieve it, we need to work with farmers and landowners. Here we interview Jez Wardman and Ryan Pape, UNDO’s two senior agronomists with a collective 50+ years of experience, to get their views on enhanced weathering and its potential. Their focus is on developing trials to test various hypotheses, among them:
- The effect silicate rock has on soil pH and how it could be used in place of lime to manage soil pH
- How basalt rock increases the presence of various nutrients and the impact this may have on reducing farmer reliance on other inputs
- Does enhanced weathering help improve the organic matter in soil?
Why should we care about enhanced weathering?Ryan: There’s plenty of scientific literature out there extolling the virtues of enhanced weathering as a carbon removal tool. Jez: Yes, it’s considered a much more permanent way of removing carbon from the atmosphere than planting trees, since the carbon is stored for thousands of years whereas a tree only stores the carbon for its lifetime. Ryan: The exciting thing about the technique is that it has the potential added benefit of improving soil nutrient load and pH along with the carbon removal.
How will you be supporting the growth of enhanced weathering?Ryan: Despite the evidence in literature that shows the benefits of enhanced weathering, for farmers to trust it, they want to see local field results. A huge part of what we do is translating lab results into results in the field. I am hugely passionate about the trials process – taking the science into the field. It’s what farmers expect, data produced in the field, in their growing environment.
What will the focus of the trials be?Jez: I’m already working closely with local farmers, research organisations and independent agronomists to establish various trials to demonstrate the agronomic benefits of enhanced weathering to soil health. There is so much potential in enhanced weathering for farmers. I’m particularly interested in exploring how spreading basalt rock can help maintain the soil pH at the correct level. At the moment, if farmers identify a drop in soil pH, they’ll spread lime – that’s the accepted practice. But I really think spreading basalt rock could have a slow-release effect, preventing the soil pH level from dropping in the first place. Farmers then benefit in two ways (1) lime cost savings, and (2) avoiding yield sacrifices linked to a drop in soil pH. Ryan: In my area soil pH is very acidic in places, so economically managing soil pH is a regular concern for farmers. We’re undertaking trials to explore how soil pH responds to our crushed basalt rock, with the ultimate goal to reduce or eliminate the need for other liming agents, providing a cost and crop benefit.
What does your crushed basalt rock contain?Ryan: UNDO work closely with quarry partners to screen the silicate rock we source. We are checking for two things:
- Level of heavy metals in the rock to ensure it’s safe for agricultural use
- Constituent minerals; both for nutrients and to maximise the weathering reaction.