We hear so much about the importance of healthy soil, but what does that really mean? Here’s a quick guide to the 3 essential components…

We sustainable gardeners all know that healthy soil is essential for a healthy garden. But what exactly constitutes “healthy” soil, and how do we know if our soil is healthy?

UrbanFarm.org notes that:

According to the Natural Resource Conservation Service, soil health (or quality) refers to “its ability to sustain life while functioning as a vital living ecosystem.” In other words, good soils support life while serving as their own unique environments!

In order to fulfill this definition, healthy soil must have 3 things: good structure, organic matter, and biological activity. Let’s take a closer look at each of these components.

1.) Good Soil Structure

Like the foundation of a well-built house, good structure is essential for healthy soil and healthy plant growth. The topsoils that boast the highest productivity often exhibit a granular structure, reminiscent of crumbled cookies. These rounded clumps of soil settle together in a loose arrangement, creating a network of pores and pockets within the soil. Think of these pores as the bustling streets and cozy alleyways of a thriving city; each one plays a unique role within the intricate ecosystem of the soil.

In this underground world, pores come in a variety of shapes and sizes. Large pores, the spacious boulevards of the soil, act as major highways, swiftly guiding excess water away from the root zone. In addition to this drainage duty, they serve as essential channels for proper ventilation, ensuring that life-sustaining oxygen reaches the roots and soil organisms while allowing carbon dioxide and other waste products to make their exit.

On the flip side, the smaller pores function like efficient water storage containers, patiently holding moisture for when plants need it most. Together, these pores create a harmonious soil environment, fostering the ideal conditions for plant growth and a thriving underground community of soil organisms.

2. Organic Matter

Organic matter, a vital ingredient in the recipe for healthy soils, plays the role of a natural adhesive, effectively binding mineral particles together like a skilled craftsman joining the pieces of a mosaic. This adhesive quality not only promotes the formation of the soil structure we just discussed but also serves as a protective shield against the relentless forces of rain and wind. Thanks to organic matter, soil aggregates remain steadfast even in the face of nature’s disruptions.

But that’s not all – organic matter dons yet another cap in its role as the guardian of soil well-being. It acts as a dependable insulator, shielding the soil system from the extremes of temperature, ensuring it doesn’t become too hot or cold. Without this guardian, the soil environment would often prove too harsh for the majority of its inhabitants.

Beyond its roles as protector and binding agent, of course, organic matter also serves up a delectable buffet for numerous living organisms dwelling beneath the surface. It becomes a source of sustenance and essential nutrients for these subterranean residents. In essence, organic matter acts as both the architect and chef of the soil ecosystem, constructing a comfortable home and providing a nourishing banquet that beckons life to flourish in this vital underground community.

3. Biological Activity

Last but not least, high levels of biological activity are inherent in healthy soils. While most of us aren’t aware of it, the bustling world beneath our feet is a thriving community, where every soil creature, from the towering trees to the tiniest microorganisms, plays an indispensable role in maintaining the delicate ecological balance. Each of these organisms has its unique part to play, but they all share a common thread – they are a wellspring of organic matter, the lifeblood of the soil.

In the cycle of life and death, plants and animals return their essence to the soil upon their demise, enriching it with the very nutrients they had once absorbed. In doing so, they inject a plethora of compounds into the ecosystem. This infusion of compounds, coupled with the physical activities of plant roots and animals, contributes to the coveted “cookie crumble” structure that is the cornerstone of soil quality as discussed above.

But the contributions of soil organisms don’t stop there; they also serve as diligent nutrient cyclers within a complex food web. The photosynthetic champions, such as plants and algae, work their magic by converting atmospheric carbon into organic tissue. In contrast, the decomposers – fungi, fly larvae, ants, bacteria, and their ilk – perform the vital task of liberating nutrients from the deceased or dying, offering them up to a diverse cast of hungry consumers.

Among these microcosmic heroes, microbes reign supreme in the realm of nutrient cycling. Some of these microscopic marvels have the remarkable ability to convert atmospheric nitrogen into forms readily available to plants, while others skillfully extract phosphorus from minerals, delivering it to grateful plant roots. Beyond these essential elements, soil organisms also orchestrate the transformation of substances like iron, sulfur, and potassium, ensuring that life’s fundamental building blocks are in the right place at the right time. In this intricate dance of life, every participant, big or small, wields their unique talents to harmonize the symphony of the soil ecosystem.

The Bottom Line

We, humans, gardeners or not, have still barely begun to scratch the surface of all that lies in the hidden world beneath our feet. We have so much more to discover, and our understanding of soil health is constantly evolving! As this article points out,

The size and variety of life forms that influence soil resources are vast, and in many cases, is still being discovered. In fact, scientists estimate that only 5% of soil-dwelling organisms have been identified thus far! What is known is that nearly all soil organisms play a unique role in promoting soil health.

No matter where we live – desert, rainforest, plains, or mountains, soil is the foundation for nearly all ecosystems. Even aquatic environments depend on healthy soils for purification and sustenance. And soil health is easily impacted by human activity. Poorly managed soils lead to unhealthy crops, lost productivity, and poor water quality.

The good news is, we can help improve the health of our planet and its inhabitants by building soil health and promoting practices that improve soil quality over time. Using organic, biodynamic, regenerative, and sustainable gardening practices in our own gardens is just one step in the right direction.