Over a pint in Oxford, we may have stumbled upon the holy grail of agriculture | George Monbiot

IIt didn’t feel like I was climbing a mountain during a temperature inversion. You struggle through fog so dense you can barely see where you’re going. Suddenly you break through the top of the cloud and the world opens up before you. It was that rare and remarkable thing: a eureka moment.

For the past three years, I have been struggling with a significant and frustrating problem. While researching my book Regenesis, I had worked closely with Iain Tolhurst (Tolly), a pioneering farmer who had achieved something extraordinary. Almost everywhere, high-yield agriculture causes major environmental damage, due to the amount of fertilizers, pesticides, and (sometimes) irrigation water and deep plowing required. Most farms with seemingly low environmental impact produce low yields. In reality, this means significant impacts, because more land is needed to produce a given amount of food. But Tolly has found the holy grail of agriculture: high and increasing yields with minimal environmental damage.

It uses no fertilizers, no animal manure and no pesticides. His techniques, the result of decades of experimentation and observation, appear to enrich the crucial relationships between crops and soil microbes, through which soil nutrients must pass. It appears that Tolly has in effect “trained” soil bacteria to release nutrients when his crops need them (a process called mineralization) and to lock them away when his crops are not growing (immobilization), ensuring that they do not escape from the soil.

So why this frustration? Well, Tolly has inspired many other producers to try the same techniques. Some have succeeded, with excellent results. Others did not. And no one can understand why. This probably has something to do with the properties of the soil. But what?

This was not the first time I came across a knowledge gap so large that humanity could cross it. Soil is an incredibly complex biological structure, like a coral reef, built and maintained by the creatures that inhabit it. It provides 99% of our calories. Yet we know less about it than about any other identified ecosystem. It’s almost a black box.

Many brilliant scientists have devoted their lives to its study. But there are major obstacles. Most soil properties cannot be observed without digging, and if you dig a hole, you damage the structures you are trying to study. As a result, the study of even fundamental properties is tedious, time-consuming and is either very expensive or simply impossible on a large scale. To measure the volume of soil in a field, for example, hundreds of cores must be taken. But because soil depth can vary significantly from meter to meter, your figure is based on extrapolation. This makes it very difficult to know whether you are losing or gaining land. Measuring bulk density (the amount of soil in a given volume, which shows how compacted it can be), or connected porosity (the tiny catacombs created by life forms, a crucial measure of soil health), or soil carbon – on a large scale – is even more difficult.

So farmers have to guess. Partly because they can’t see exactly what the soil needs, many of their inputs – fertilizer, irrigation, deep tillage – are wasted. About two-thirds of the nitrogen fertilizer they apply and between 50 and 80 percent of their phosphorus are lost. These lost minerals cause algae blooms in rivers, dead zones at sea, costs for water users and global warming. Huge amounts of irrigation water are also wasted. Farmers sometimes “subsoil” their fields – deep, damaging plowing – because they suspect compaction. Suspicions are often wrong.

Our lack of knowledge also hinders the development of new agriculture that could, as Tolly did, allow farmers to replace chemical augmentation with biological enhancement.

So when I decided to write the book, I made a statement so vague that it read like an admission of defeat: we needed to spend massively on “advanced soil science” and use it to lead a “greener revolution.” While we know almost nothing about the surface of our own planet, billions are being spent on the Mars Rover program, aimed at exploring barren regolith. What we needed, I argued, was an Earth Rover program, mapping the world’s agricultural soils at much finer resolution.

I might as well have written “something must be done!” The necessary technologies simply did not exist. I was sinking into a Stygian darkness.

AAt the same time, Tarje Nissen-Meyer, then a professor of geophysics at the University of Oxford, was grappling with a different challenge. Seismology is the study of waves passing through a solid medium. Thanks to billions coming from the oil and gas industry, it has become very sophisticated. Tarje wanted to use this powerful tool for the opposite purpose: ecological improvement. He and colleagues had already deployed seismology to study elephant behavior in Kenya. Not only was it very effective, but his team also discovered that he could identify animal species roaming the savannah by their signatures.

As luck would have it, we were both attached, in different ways, to Wolfson College, Oxford, where we met in February 2022. I immediately saw that he was a thoughtful man – a visionary. I suggested a pint at the Magdalen Arms.

I explained my problem and we talked about the limitations of existing technologies. Was seismology used to study the soil, I asked. He had never heard of it. “I guess it’s not appropriate technology then?” No, he told me, “the soil should be a good medium for seismology. In fact, we need to filter out the noise from the soil when we look at the rocks.” “So if it’s noise, it could be a signal?” “Certainly.”

We looked at each other. Time seemed to have stopped. Could this really be true?

Over the next three days, Tarje conducted desk research. Nothing happened. I wrote to Professor Simon Jeffery, a leading soil scientist at Harper Adams University, whose advice I had found invaluable when researching the book. I set up a Zoom call. He would surely explain that we were barking up the wrong tree.

Simon is generally a reserved man. But when he finished questioning Tarje, he became very animated. “All my life I’ve wanted to ‘see’ into the ground,” he said. “Maybe now we can do it.” I was introduced to a brilliant operations specialist, Katie Bradford, who helped us build an organization. We created a non-profit organization called Earth Rover Program, to develop what we call “soilsmology”; build open source hardware and software cheap enough to be useful to farmers around the world; and create, with farmers, a self-improving global database. We hope this could one day integrate all soil ecosystems: a sort of human genome project for soil.

We later discovered that some scientists had actually sought to apply seismology to the ground, but that this had not been developed into a program, in part because the approaches used were not easily scalable.

My role was mainly to repair, find money and other help. We received $4 million (£3 million) in seed money from the Bezos Earth Fund. This may cause some discomfort, but our experience was entirely positive: the fund helped us do exactly what we wanted. We also benefited from the pro bono assistance of the law firm Hogan Lovells.

Tarje, now at the University of Exeter, and Simon began putting together their teams. They would need to develop a variant of ultra-high frequency seismology. A major obstacle was cost. In 2022, suitable sensors cost $10,000 (£7,500) each. They managed to reuse other kits: Tarje discovered that a geophone developed by a Slovak experimental music group worked just as well and cost only $100. Today, one of our scientists, Jiayao Meng, is developing a sensor for around $10. Over time, we should be able to use cell phone accelerometers, reducing the cost to zero. As for generating seismic waves, we get all the signal we need by hitting a small metal plate with a welder’s hammer.

During its first deployment, our team measured the volume of a peat bog that scientists have been studying for 50 years. After 45 minutes in the field, they produced a preliminary estimate suggesting that previous measurements were off by 20%. Instead of extrapolating peat depth from grab samples, they could see the wavy line where the peat met the subsoil. The implications for estimating carbon stocks are enormous.

We were also able to measure the apparent density on a very fine scale; monitor soil moisture (as part of a larger team); start building the AI ​​and machine learning tools we need; and see the different impacts of different crops and agricultural treatments. We will then work on measuring the porosity, texture and carbon of the soil; an extension to the hectare level and beyond; and on testing the use of phones as seismometers. We now have additional funding from the UBS Optimus Foundation, hubs on three continents and a large international team.

We hope that eventually any farmer, rich or poor, will be able to get an almost instant reading of their soil. As more people use these tools and build the global database, we hope that these readings will translate into immediate useful advice. These tools are also expected to revolutionize soil protection: the EU has published a law on soil monitoring, but how can it be implemented? Farmers are paid for their contributions “to improve soil health and resilience”, but in practice this means just ticking a box on a grant form: there is no sensible way to check.

We are not replacing the excellent work of other soil scientists, but, by developing our methods alongside theirs, we believe we can fill some of the considerable knowledge gap. As one of the farmers we work with, Roddy Hall, notes, the Earth Rover program could “take the guesswork out of farming.” One day, it might help everyone reach that happy point: high returns with low impacts. Seismology promises to make things happen.