The earth under our feet is too often ignored – and yet there can be no life without it
Healthy soils are essential for our food security: 95% of our food comes from the earth. It is also the planet’s largest natural water filter, helping supply the world with clean water. Soil even helps regulate the climate – storing more carbon than all the world’s forests put together.
Soils are also one of the most active ecosystems on earth. A handful of soil contains more organisms and micro-organisms than the planet’s entire human population. Worldwide soils encompass one quarter of the planet’s biodiversity, including billions of microbes that are the foundation of today’s antibiotics.
In short, soil is integral to keeping the world healthy. But healthy soil is being lost at a worrying rate – soil fertility is declining, and soil erosion and land overdevelopment is seeing us lose potentially productive land forever.
The scale of the situation
The numbers are stark: Erosion carries away around 24 billion tons of topsoil every year, leading to annual cereal production losses of around 7.6 million tons. If action is not taken to reduce erosion, we could see a total loss of over 253 million tons of cereals by 2050. This yield loss would be equivalent to removing 1.5 million square kilometers of land from crop production – or roughly all the arable land in India.
Much of the reason for the loss of fertile soil comes from the escalating competition for land and how we currently manage it.
A rapidly growing, increasingly urban global population is demanding more food – and more land to build on. In response, farming has had to become increasingly intensive to help feed the ever-expanding populace. There has been a focus on specialization through monocultures (single plants or crops), which can deplete the soil of vital nutrients, and increase vulnerability to erosion by wind and rain.
The Food and Agriculture Organization (FAO) predicts that if this trend continues at its current rate, we have about 60 years of harvests left. As US President Franklin D Roosevelt once said, “The nation that destroys its soil destroys itself.”
“Buy land, they’re not making it anymore” – Mark Twain
The issue is fertile soil is a finite resource. We can’t just go about creating a fresh batch whenever we need to. Once it’s gone, it’s gone.
The process of creating soil is complex, involving the physical and chemical weathering of rock over time into mineral particles – of sand, silt and clay – combined with water, air and organic matter that has been broken down by microbes and chemical reactions over hundreds of years.
It takes around 2,000 years to create just 10 centimeters of topsoil and yet it can be destroyed in an instant. So preventing soil erosion is vital.
“If you just have rock, no matter how much fertilizer or how many microbes you have, you won’t be able to get a plant to grow,” says Magalie Guilhabert, Head of Crop Efficiency for Biologics Research at Bayer.
So is the situation irreversible or can we do something to change it?
Science and a sustainable solution for soil
The world has been slow to wake up to the critical need to conserve our soils but the good news is that there is now a concerted effort to tackle the problem. The UN is urging governments to introduce policies that encourage farmers, through education, regulation and financial incentives, to farm more sustainably and prevent further degradation.
Scientific advances are also making a big difference in restoring the health of soil.
Over the last decade or so, advances in genetic sequencing have helped identify ever more microbes that can help soils recover their fertility – and help plants use the nutrients in soil more effectively.
“The science of using microbes to help crops isn’t new,” says Guilhabert. “What is new are the tools we have to understand the complexity of their genetics, to better target their use to maximize the productivity of soil without causing long-term harm.”
Today, a vast array of microbes are being used by farmers to help optimize fertilizer application (meaning less fertilizer needs to be used), to stimulate root growth (helping plants thrive in soils traditionally seen as substandard), and to clean up pollutants in both soil and water. These tiny organisms are increasingly bringing the earth back to health.
Digital agriculture is also playing its part - helping farmers not only to increase yields to meet our growing demand for food but to do so in a more sustainable way. Farmers are using precision farming techniques to constantly monitor the condition of both their crops and the soil from which they grow, helping to maintain healthier, more productive land.
In the future, the increased use of sensors and even more specialist microbes promises the potential to micro-target the use of fertilizer, irrigation and microbes to maximize the revitalization of soil health, helping to increase crop yields and ensure our future food security.
For now, providing farmers with the technology and support to best manage their land both sustainably and productively is vital. As Josse Peeters from the Hof ten Bosch farm, Belgium, says: “For every farmer, one of the principal challenges is maintaining soil fertility and reducing soil erosion. There has to be a balance between raising productivity and protecting biodiversity.”