Tuesday 13 September 2011

Crops with deeper roots capture more carbon, fight drought

Creating crops with deeper roots could soak up much more carbon dioxide from the air, help mankind fight global warming and lead to more drought-tolerant varieties, a British scientist says in a study. Douglas Kell of the University of Manchester says crops can play a crucial role in tackling climate change by absorbing more of mankind's rising greenhouse gas emissions from burning fossil fuels.

Doubling root depth to two metres would also make crops more drought resistant, improve soil structure and moisture, store more nutrients and reduce erosion, Kell says in the study published online in the Annals of Botany journal. Plants use carbon dioxide (CO2) and sunlight to grow and carbon is stored in the roots and leaves. Deeper and more bushy roots would store more carbon underground.

Many crop varieties have root systems that don't extend beyond one metre, limiting their access to water during drought but ensuring rapid growth above ground and bumper yields when the weather is good.

"Doubling root biomass to a nominal two metres is really the key issue, together with the longevity of the carbon they secrete and sequester below-ground," Kell says in the study.

He said previous studies have doubted the benefits of deep roots locking away large amounts of carbon. But this was because the studies did not take soil measurements much below a metre.

"What matters is not so much what is happening now as what might be achieved with suitable breeding of plants with deep and reasonably long-lived roots. Many such plants exist, but have not been bred for agriculture," he says.

Read more from Reuters here.