Restoring soils fit for future generations

Combining the lessons of agricultural history with the insights of modern biotechnology is the key to reversing the lethal degradation of the world's soil base, which is now threatening humanity's ability to feed a growing global population.

SoilThis was the powerful message Sheffield's researchers gave to leading policy makers on the eve of a crucial climate change gathering in Paris – the 21st Conference of Parties on Climate Change (COP21).

Speaking at Chatham House in the run up to COP21, plant and soil scientist Professor Duncan Cameron, and his colleague Professor Colin Osborne, an expert in the evolutionary and environmental physiology of plants, warned that time is rapidly running out for a change in direction. Failure to act quickly could trigger food shortages around the world, with knock on effects in increased mass migration, political and social instability and conflict.

"The current system of agricultural intensification, which consumes 5% of the world’s natural gas and 2% of its energy, is not sustainable," says Professor Cameron, who heads the P3 Plant Production & Protection research group at Sheffield, a 2022 Futures initiative backed by £8.5 million of university investment. "Even with the current levels of intensification, the yields from a number of key crops have been flatlining for the last fifteen years. The model doesn't work."

Their research shows the degraded status of the world's soil is largely responsible for this yield plateau. "Soil is lost rapidly but replaced over millennia and this represents one of the greatest global threats for agriculture."

Cameron and Osborne have discovered that elite modern crops, which are optimised to a system of high nutrient inputs and chemical control of pests and disease, have lost their natural partnerships with microbes to extract complex nutrients from the soil and build up their defences against natural enemies.

"Soil is becoming a hydroponic system: a physical substrate to support plants, but providing little else. Deep ploughing has caused a decline of soil organic carbon, with adverse effects for water-holding abilities and the natural supply of nutrients, and a loss of structure that allows rapid soil erosion," says Professor Osborne, Associate Director of the Grantham Centre for Sustainable Futures.

Despite this gloomy backdrop, the Sheffield team believe that all is not lost. "Our nineteenth century farming forebears had little access to artificial fertilisers, and consequently had to manage the soil well. The combined application of manures and the rotation of annual crops with grass and nitrogen-fixing legume cover crops, recharged soil carbon and nutrients as well as rebuilt the soil physical structure."

While this method is still practised on organic farms, the yields are too low to be able to sustain a growing global population. "But a combination of the lessons of history with the benefits of modern technology could provide a sustainable model of intensive agriculture,” Cameron and Osborne argue. The clever rotation of annual and cover crops, plus the application of manure, will restore the vitality of the soil.

A combination of the lessons of history with the benefits of modern technology could provide a sustainable model of intensive agriculture

Professor Duncan Cameron and Professor Colin Osborne

Biotechnology, meanwhile, could be used to wean crops off the addictive chemical cocktails they have become all too dependent upon. And, in a Back to the Future scenario, we could even recycle sewage in industrial scale biorefineries to create a modern example of a sustainable, circular economy.

"A sustainable soil-centric reengineering of the agricultural system then leads to lower requirements for fertiliser inputs and pesticide application, as well as reduced irrigation, thus safeguarding finite natural resources," the two researchers told the gathering of policy makers and fellow researchers.

Perhaps the biggest hurdle to adopting this approach, however, is not the technical and scientific challenges, but the political, economic and social obstacles. "To facilitate such a wholesale redesign of the agricultural system, we need to assess the potential scientific, economic, cultural and political impediments to this happening, and resolve the potential benefits of this redesign for sustainability. In doing so, we could create a soil fit for future generations, reducing our dependence on energy-intensive and non-renewable inorganic fertiliser supplies as well reducing pollution in watercourses as a result of fertiliser run-off."

Grantham Centre for Sustainable Futures

Sheffield's £2.6 million Grantham Centre for Sustainable Futures brings together a powerful collection of interdependent, multidisciplinary teams whose research is breaking new ground in finding solutions to the grand challenges of climate change, food and energy security, water scarcity and environmental resilience.

"Grantham gives us both the research tools and the voice through which to communicate our research to policy makers in a way that enables us to maximise our impact on these big environmental challenges," says Grantham’s Associate Director Professor Colin Osborne.

"Grantham brings together research teams from every possible discipline, from the social to the physical sciences, giving our partners easy access to the thought leaders in their fields, and enabling excellent fundamental research to be more rapidly translated into real world solutions to real world problems," he added.

P3 - Plant Production and Protection

Translating our basic plant and soil sciences research into practical solutions to feed the world’s expanding population.

More people die each year from hunger and malnutrition than from AIDS, tuberculosis and malaria combined and the question of how we will feed our rapidly expanding global population is urgent and non-trivial. The UK is committed to leading a new Agricultural Revolution that will feed the world whilst protecting our landscapes and preserving environmental assets.

In response, we're pioneering a translational approach that builds on our internationally recognised research in plant sciences, to address agricultural challenges experienced by real world producers and land carers.