An evolving understanding of cover crops with a regenerative perspective
Many growers approach cover cropping with a narrow objective, such as erosion control. They ask, “What are the best planting methods?” and “What mix should I use?”
However, new research has led to a growing awareness of the many benefits of cover crops: weed suppression, nutrient cycling, improved soil structure, enhanced biodiversity, and more. This broader understanding has led to a shift in mindset and strategy. Recently I’ve observed growers starting to use cover crops as a panacea — to increase biological life in the soil; balance its physical, chemical, and biological aspects; and ultimately improve plant health, crop yields, and nutrient integrity.
Because of all these benefits, more growers are managing their cover crops with the same attention they give to their cash crop. This includes amending and preparing the soil, inoculating the seed, and foliar spraying to correct nutrient deficiencies.
Amidst all this, it’s vital not to lose sight of cover crop fundamentals — selecting the right plant species, mixing appropriate families, planting at the right time, having a termination plan, and aligning everything to your goals and cropping cycle. If you’re already familiar with these concepts but want to understand more deeply how cover crops can impact plant and soil health, then this article is for you.
Establishing Covers
Before diving beneath the soil surface, let’s take a step back.
Growers often face challenges establishing cover crops. For those approaching cover crops with fresh eyes, it’s worth pausing to consider the root causes of unsuccessful establishment. These issues are usually the result of a complex interplay between soil health, environmental conditions and management practices.
First, it’s essential to examine possible systemic problems. Poor soil health stems from imbalances in the soil’s physical, chemical and biological dimensions. This often manifests as degraded structure. Compaction — whether caused by machinery or natural settling — can limit root penetration, reduce water infiltration and create anaerobic zones, all of which impede seed germination and seedling growth. Environmental stressors such as prolonged drought, excessive rainfall, late frosts or extreme temperatures also hinder establishment.
Second, there are management-related challenges. These include suboptimal planting practices, species mismatches, biotic pressures, excessive or insufficient residue, and lack of diversity. Poor timing — planting too early or too late — can result in inadequate biomass development. Poor seed-to-soil contact due to improper soil prep, planting depth or moisture conditions can prevent seeds from absorbing enough water to germinate. Incorrect seeding rates can lead to poor coverage or self-suppression.
Seed quality also matters; some growers opt for lower-cost seeds without understanding the importance of nutrient integrity, epigenetics or endophytic communities. Choosing species that don’t align with your soil type, pH, drainage, climate or objectives (e.g., using non-legumes when N-fixation is the goal) is another common mistake. Excessive residue can delay germination, introduce allelopathic compounds or cause mineral imbalances. Conversely, too little residue may expose the soil to moisture loss, erosion or temperature extremes.
Finally, always plan your termination strategy. Failing to terminate a cover crop correctly can result in it competing with or even overtaking your cash crop — a costly mistake.
Cover Your Goals
It never ceases to amaze me how well-rounded growers must be to succeed. They’re land stewards, but also need to know finance, biology, chemistry, mechanics, human resource management and more. Fortunately, much of the know-how needed for effective cover cropping mirrors what growers already understand about their cash crops. Once you understand the “why,” the “how” and “when” fall into place more easily.
Among the first questions to ask yourself are, “What are my goals? What problems am I trying to solve with cover crops?” Your answers will shape the species you select. Are you trying to build short-chain carbon to feed microbes? Or is your focus on stable long-chain carbon for water retention and ion homeostasis? Are you looking to increase nitrogen? Provide ground cover with high biomass? Feed microbes? Break compaction? Attract pollinators and beneficials? Suppress pathogens with plant secondary metabolites from root exudates? Remediate soil contaminants through bioremediation? Reduce salinity or sodicity? And if you plan to graze or harvest the cover crop, are you avoiding species that produce alkaloids such as solanine?
Cover crops can do all these things and more, but each plant species has its specialty, so I strongly recommend doing in-depth research or consulting with a cover crop specialist to choose the right mix. A good starting point is the work of Keith Berns, founder of Green Cover. Nature is marvelously complex, but when we work with it rather than against it, we unlock its full potential.
Underground Cover
Now let’s journey underground. Cover cropping plays a foundational role in regenerating soil, supporting plant health and stabilizing agro-ecosystems.
We often hear that diversity is key in cover cropping, and that’s absolutely true. Diversity of root structure — whether fibrous or deep tap roots — is one objective. But there’s more to it than that.
Consider quorum sensing. In microbiology, this is the process by which bacteria, upon reaching a certain population density, change their gene expression and behavior — acting less like individuals and more like a coordinated multicellular organism. This process underlies phenomena like biofilm formation, bioluminescence in dinoflagellates, and pathogen virulence.
Plants exhibit similar cooperative potential. In monocultures or isolated environments, they must perform all survival functions independently. But diverse multispecies plant communities allow for specialization. Some excel at phosphorus solubilization, others at nitrogen fixation or salt tolerance. Just as microbes can shift behavior when densely populated, plants can collaborate instead of compete — creating synergies that mimic natural ecosystems. Combine this with beneficial microbial partnerships, and you begin to see how nature can sustain itself without external inputs.
Soil structure deserves a deeper conversation, but suffice it to say that healthy soil depends on a balance between the physical, chemical and biological realms. Texture and mineralogy are important, but the biological activity — driven by root exudates and photosynthetic energy — is what keeps the system dynamic. We can grow plants without soil, but we can’t maintain soil structure without plants and microorganisms.
Plants and microbes together regulate key soil parameters: redox potential (Eh in mV), pH (hydrogen potential), and electroconductivity (E.C. in dS/m), all of which govern nutrient availability. It’s also important to consider metrics like the clay:carbon ratio, organic matter, organic carbon to organic nitrogen ratio, and microbiologically active carbon. These and other metrics from tests like the Haney Soil Health Test help inform targeted actions. Misinterpreting them can lead to misguided strategies and worsen issues such as nitrogen loss through denitrification.
A particularly exciting discovery is the rhizophagy cycle, as described by James White. We now understand that plants can actively recruit and internalize beneficial microbes to extract nutrients, enhance stress tolerance or produce phytohormones.
Understanding these principles allows us to develop strategies that bring soil back to life. Take nitrogen: most growers understand its importance, but not everyone realizes that whether nitrogen exists as nitrate (NO3–) or ammonium (NH4+) is dictated by redox conditions. Even if you apply ammonium, an oxidized soil environment will shift it toward nitrate — and vice versa.
When agronomic decisions are grounded in sound principles, the outcomes speak for themselves. Benefits include better water retention, erosion control, infiltration, soil aggregation, fertility, pest and disease suppression, and ultimately, healthier crops and more nutrient-dense food. If you are interested in knowing more about how plant nutrition can increase resistance to diseases, look into Don Huber’s work in Mineral Nutrition and Plant Disease. And if you want to know why insects only are attracted to weak plants, you might find Tom Dykstra’s work fascinating.
A Cover Story
To illustrate what’s possible, I want to share an example from a vineyard in Southern California. Greg Pennyroyal, the vineyard manager, has spent over six years implementing a regenerative system. He’s used plant sap analysis for nutrient management, addressed physical and chemical soil limitations, managed compaction and mineral imbalances, incorporated diverse cover crops, introduced livestock, optimized irrigation quality, applied biostimulants and inoculants, and even factored in epigenetics and endophyte presence in genetic selection.
The results are remarkable. Water usage has dropped by 30 percent. Water infiltration is four times faster than in a control block. According to the Haney Test, his soil shows 60 percent more organic nitrogen, double the organic-to-inorganic nitrogen ratio, five times higher soil respiration, 40 percent more organic carbon, and 3.4 times the microbiologically active carbon — all within optimal ranges. Overall soil health is 2.6 times higher than a conventional vineyard just two miles away.
Regeneration means bringing life back into the soil. When done right, cover crops are a powerful tool in this journey. There is a wealth of science and tradition behind using the right plants, microbes and techniques. Understanding these concepts is the first step toward becoming a better steward of the land.
The most important message I can share is this: be grateful for the privilege of working the land. Be humble, yet diligent, in the pursuit of excellence. As growers, we hold the power to transform agriculture and leave a thriving legacy for future generations.
Pedro Rioseco Escudero is a consultant with Advancing Eco Agriculture.
