Soil conservation efforts can help maintain healthy soils for thousands of years, in contrast to nearly a fifth of soils worldwide that have less than a century of life in them, according to a new study.

The major new report from a global collaboration of scientists, including the UK’s Lancaster University, found that 90 per cent of conventionally farmed soils were thinning, and 16 per cent had lifespans of less than a century.

The authors said the findings affirmed the need for “urgent action” to ensure the health of soils for future generations.

The study, led by Lancaster University in collaboration with researchers from Chang’an University in China, and KU Leuven in Belgium, brought together soil erosion data from around the globe, spanning 255 locations across 38 countries on six continents.

Their research included soils that are conventionally farmed, as well as those managed using soil conservation techniques, to find out how changes to land use and management practices can extend the lifespans of soils.   

Rapidly thinning soils were found all over the world, including countries such as Australia, China, the UK, and the USA. 

Co-author of the study, Professor Jess Davies, Lancaster University, said: "Whilst 16 per cent of soils with lifespans shorter than 100 years is a more optimistic estimate than '60 harvests left', soil is a precious resource and we can't afford to lose that much over a human lifetime.

"But importantly what our study also shows is that we have the tools and practices to make a difference - employing the appropriate conservation methods in the right place can really help protect and enhance our soil resource and the future of food and farming."

In January this year the government included protecting soil health in its new Agriculture Bill, currently nearing ratification in Parliament.

Gareth Morgan, head of farming and land use policy at the Soil Association, said: “This study underlines the gravity of the soil crisis – but it also gives us a reason to hope. Agroecological farming can support healthy soil formation, produce healthy food and encourage biodiversity at the same time.

"Government must recognize that healthy soils are critical to the future of UK food and farming by setting clear baseline standards and rewarding farmers for protecting soils through measures in the agriculture and environment bills, and future farm support schemes.”

According to the authors, converting arable land to forest was found to be the best way to lengthen soil lifespans. 

Other approaches that give soils a longer lifespan, such as cover cropping, where plants are grown between cropping seasons to protect the soil, were also shown to be highly effective. 

The ploughing of land along contours rather than down slope, and hillslope terracing were similarly suggested as beneficial for lengthening soil lifespans.

Lead author of the study Dr Dan Evans, Lancaster University, said: "Our soils are critically important and we rely on them in many ways, not least to grow our food. There have been many headlines in recent years suggesting that the world's topsoil could be gone in 60 years, but these claims have not been supported with evidence. This study provides the first evidence-backed, globally relevant estimates of soil lifespans. 

"Our study shows that soil erosion is a critical threat to global soil sustainability, and we need urgent action to prevent further rapid loss of soils and their delivery of vital ecosystem services."