Soil Secrets That Could Save the Climate

In 1859, Charles Darwin published On the Origin of Species, forever changing how we understand life on Earth. Few people know that his final book, published in 1881 just months before his death, was about earthworms. Darwin spent decades studying how these creatures transform soil, concluding that "it may be doubted whether there are many other animals which have played so important a part in the history of the world." He was onto something. The soil beneath our feet holds more carbon than all the world's forests combined, and right now, 40% of it is degraded—no longer able to support plant growth, retain water, or store carbon effectively.

The Carbon Crisis Hiding Underground

Soil ranks as the second-largest active carbon pool on the planet after the oceans. When healthy, it acts as a massive carbon sink, pulling CO2 from the atmosphere and locking it away in organic matter. But conventional agriculture has reversed this process. Excessive tillage, monocultures, and chemical-heavy farming have turned agricultural soil into a carbon source rather than a sink. Each time a plow cuts through earth, it tears apart the delicate fungal networks and soil aggregates that hold carbon in place, releasing it back into the atmosphere.

The irony cuts deep: agriculture, which depends entirely on healthy soil, has become the leading driver of soil degradation globally. Yet this same system could be part of the climate solution. A growing body of research shows that specific farming practices can rebuild soil health while simultaneously capturing atmospheric carbon—effectively reversing decades of damage.

What Makes Agriculture "Regenerative"

Regenerative agriculture isn't a single technique but a collection of practices that work with natural systems rather than against them. Seven approaches have emerged as particularly effective at restoring soil carbon: cover crops, mulching, crop rotation, intercropping, minimum tillage, managed fallowing, and rotational grazing.

Each practice addresses a different aspect of soil health. Cover crops act as armor between growing seasons, preventing erosion while their roots pump carbon into the ground year-round. When legumes serve as cover crops, they fix atmospheric nitrogen, reducing the need for synthetic fertilizers. Mulching creates a protective layer that feeds soil microbes as it decomposes. Crop rotation maintains fertility by alternating plants with different nutrient demands—nitrogen-hungry corn following nitrogen-fixing beans, for instance.

The most counterintuitive practice might be minimum tillage. Farmers have plowed fields for millennia, but leaving soil undisturbed allows carbon to accumulate in stable forms. Without the plow's disruption, fungal networks can spread and soil aggregates can form, creating structures that trap carbon for decades or longer.

A recent analysis of 345 soil carbon measurements across arable cropland and vineyards found that all seven practices effectively increased carbon sequestration rates, with no statistically significant differences among them. More importantly, combining multiple practices appears to enhance results beyond what any single approach achieves alone.

Testing Regeneration Where It Matters Most

In February 2026, the National Geographic Society and PepsiCo announced five new research grants targeting regenerative agriculture in climate-stressed regions. The projects span continents and crops, from coffee farms in Ethiopia to wheat fields in Spain, but they share a common goal: building scientific evidence for practices that can scale.

Hewan Degu is studying intercropping systems in Ethiopia's coffee-growing regions, where coffee originated. By planting potatoes between coffee trees, farmers can potentially improve soil health while diversifying income. In Indonesia, Al Greeny S. Dewayanti is testing whether intercropping sacha inchi—an omega-3-rich vine—with maize can rebuild degraded soil. She's using DNA metabarcoding to track microbial changes and developing an AI-powered app to help farmers interpret results.

The choice of locations reflects agricultural reality. These aren't demonstration farms with ideal conditions. Ahan Dalal is working in Spain's Mediterranean region, testing how biochar and cover crops perform under drought scenarios. Jamie Spychalla is examining whether nitrogen-fixing alfalfa can help Wisconsin potato farmers cope with climate-induced moisture stress. The research deliberately targets major crops—wheat, maize, potato, soy, and coffee—in places where climate change is already disrupting yields.

The Livestock Question

Rotational grazing complicates the regenerative agriculture narrative. Conventional wisdom treats livestock as environmental villains, and for good reason: confined animal feeding operations concentrate waste, produce methane, and require massive feed inputs. But rotational grazing operates differently.

The practice mimics wild herds, moving animals between paddocks before they overgraze. This stimulates plants to grow deeper root systems, which pump more carbon into soil and improve its structure. The animals' hooves break up soil crusts, allowing water infiltration. Their manure feeds soil microbes. In Wisconsin, Omar de Kok-Mercado is testing whether native prairie plantings on marginal farmland can create biodiverse corridors across corn, soy, and wheat operations—essentially building a "wild grid" that supports both wildlife and soil health.

The distinction matters because it challenges the binary thinking that dominates food system debates. The question isn't whether animals belong in agriculture, but how they're managed.

From Research to Ten Million Acres

PepsiCo's involvement raises inevitable questions about corporate influence in agricultural research. The company, which generated nearly $94 billion in revenue in 2025, has committed to spreading regenerative practices across 10 million acres by 2030. That scale of adoption could meaningfully shift agricultural carbon emissions, but it also means a major food corporation is helping shape what "regenerative" means in practice.

The European Commission has set a target of 75% healthy soils by 2030, recognizing that soil organic carbon serves as the main indicator of soil health. Beyond carbon sequestration, healthy soil affects human nutrition through the microbiome-gut-brain axis, the pathway by which soil microbes influence the microbes in our gut, which in turn affect brain function and mental health.

The challenge now is moving from research plots to working farms at scale. Cover crops increase yields for some farmers and decrease them for others, depending on local conditions. Minimum tillage requires different equipment and different timing. These practices demand knowledge and adaptation, not just new seed or equipment purchases. The research projects funded through partnerships like National Geographic and PepsiCo's collaboration will help identify which practices work where, but implementation will ultimately depend on farmers having the support and incentive to change methods that have defined agriculture for generations.