Going underground: How roots could hold the answers to our soil health problem

Caroline Stocks
5 min readMar 22, 2019

From managing residues to applying manures, for years advice around improving soil quality has focused on the surface of soil.

But for soil health expert Joel Williams, it’s what’s happening below ground that should be capturing farmers’ attention if they really want to make a difference to soil organic carbon.

Root matter — often ignored as a simple by-product of surface-protecting cover crops — is being uncovered as the unlikely hero in the battle to improve soil quality.

And by keeping soils covered year-round with living plants, encouraging root growth could be the key to replenishing soils and nurturing them back to health.

Soil health has been in decline thanks to intensive farming practices

“There have been several concrete studies now which indicate that root matter is more important than shoot matter when it comes to improving soil quality,” says Mr Williams of independent consultancy Integrated Soils.

“Research shows that roots are five-times more likely to be converted into stable organic carbon than the equivalent of above-ground carbon.

“That really shifts the focus to below ground, when for so many years we’ve focused on what’s happening on top.”

Cover crops

In practical terms, that means farmers should be taking a fresh look at cover crops, Mr Williams says — perhaps just not for the reasons they have in the past.

“Organic matter above ground does important things like mulching the soil and protecting it from wind erosion and rainfall impact.

“It’s also very important for conserving soil moisture, which is critical when we have dry summers like we had last year. And of course it provides an important habitat for wildlife and food for the earthworm.

“There’s definitely a lot to be said for maintaining litter on the surface, it’s just emerging that it’s not a key driver for building soil organic carbon; it’s root matter that offers more.”

Going back to the roots

While the benefits of root matter may have been proven, new research looking into the impacts of living root exudates on the soil suggest that they have an even greater role in soil…

--

--

Caroline Stocks

UK journalist via Spain and the US • Writes about food, agriculture and the environment • Agtech nerd •