Breeding crops with roots a metre deeper in the ground could lower atmospheric CO2 levels dramatically, with significant environmental benefits, according to research by a leading University of Manchester scientist.
Writing in the Annals of Botany, Professor Douglas Kell argues that developing crops that produce roots more deeply in the ground could harvest more carbon from the air, and make crops more drought resistant, while dramatically reducing carbon levels.
In principle, any crops could be treated in this way, giving more productive yields while also being better for the environment.
Although the amount of carbon presently sequestered in the soil in the natural environment and using existing crops and grasses has been known for some time, Professor Kell’s new analysis is the first to reveal the benefits to the environment that might come from breeding novel crops with root traits designed to enhance carbon sequestration.
Professor Kell, Professor of Bioanalytical Science at the University as well as Chief Executive of the Biotechnology and Biological Sciences Research Council (BBSRC), has also devised a carbon calculator that can show the potential benefits of crops that burrow more deeply in the ground.
With this, he has calculated that — depending on the time it takes them to break down -breeding crops that could cover present cropland areas but that had roots a metre deeper in the soil could double the amount of carbon captured from the environment. This could be a significant weapon in the fight against climate change.
The soil represents a reservoir that contains at least twice as much carbon as does the atmosphere, yet mainly just the above-ground plant biomass is harvested in agriculture, and plant photosynthesis represents the effective origin of the overwhelming bulk of soil carbon.
Breeding crop plants with deeper and bushy root ecosystems could simultaneously improve both the soil structure and its steady-state carbon, water and nutrient retention, as well as sustainable plant yields.
Professor Kell argues that widespread changes in agricultural practice are needed, in an environment in which edible crop yields also need to increase substantially and sustainably, and where transport fuels and organic chemicals will need to come from modern (rather than fossil) photosynthesis.
It is known that massive CO2 reductions in the atmosphere over geological time have happened because of the rise of deep-rooted trees and flowering plants.
Most cultivated agricultural crops have root depths that do not extend much beyond one metre. Doubling this, Professor Kell argues, would dramatically reduce CO2 levels.
