Healthy soil as carbon sink: a solution to climate change?

Many of us enjoy the outdoors, gardening or even tending to a small farm. But today, we feel the heat — literally — of climate change. It’s a global problem, and we often wonder how we can make a difference. Surprisingly, the answer might be right beneath our feet: the soil.

What is soil, really?Soil is the top layer of the earth where plants grow, often called the “skin of the Earth.” But it’s not just dirt — soil is alive! Just one teaspoon of healthy soil contains more microorganisms than there are people on Earth. These tiny organisms help break down organic matter and make nutrients available to plants.

About 95% of our food, directly or indirectly, comes from soil. Even 95% of antibiotics are derived from soil bacteria. Truly, soil is life.

What is healthy soil made of? Healthy soil is composed of 45% minerals (sand, silt, clay, pebbles, rocks, 25% air, 25% water, and 5% organic matter (plants, animals, and microorganisms).

The most fertile part of soil is the topsoil, especially when it contains humus, which is a dark, rich substance formed from decomposed leaves, twigs, insects, and other organisms. Humus is about 60% carbon, and it’s essential for water retention, nutrient balance, and soil structure.

THE ROLE OF SOIL IN CLIMATE CHANGECarbon in the atmosphere contributes to global warming. But when plants photosynthesize, they pull carbon dioxide from the air and send some of that carbon into the soil through their roots. When the soil is rich in organic matter and microorganisms, it stores or “sequesters” this carbon. This process turns soil into a carbon sink.

Unfortunately, many farming and land use practices destroy this process, including slash-and-burn agriculture, the use of chemical fertilizers and pesticides, tilling and plowing, illegal logging, and overgrazing by livestock. These activities kill beneficial microbes and release stored carbon back into the atmosphere.

So how do we restore soil health? Theseare some simple, powerful ways through which we can support healthy soil, and, in doing so, have healthy plants and even store carbon in the soil and help against climate change:

1. Compost — Kitchen scraps and yard waste can be turned into compost. This adds organic matter to soil, feeds microbes, and reduces landfill waste. Even simple segregation — separating biodegradable (nabubulok) from non-biodegradable (hindi nabubulok) waste —makes a difference. Composting also feeds earthworms, whose castings or vermicast are excellent fertilizers.

2. Mulch — A “blanket” of dried leaves or wood chips protects the soil from heat and erosion. It keeps moisture in, regulates temperature, and slowly releases nutrients as it decomposes.

3. Cover crops — Planting nitrogen-fixing crops like monggo or mung beans between growing seasons keeps soil covered, adds organic matter, and prevents erosion. Cut these crops before flowering and mix into the soil as green manure — this works like a spa treatment for soil!

4. Well-rotted manure — Animal manure from chickens, pigs, cows, goats, or rabbits, when properly composted, is a natural way to enrich the soil with nutrients and organic material.

These are some practices of what’s called regenerative farming or carbon farming — farming in a way that follows nature’s cycles and heals the land.

I used to rely on synthetic fertilizers. But since discovering natural farming — which cares for the microorganisms in the soil — in the mid-2000s, I’ve been hooked. Most of the materials are free and abundant, such as leaves, kitchen waste, animal manure. I also learned about JADAM, an ultra-low-cost organic farming system using leaf mold, or decomposed leaves, which makes one of the best soil conditioners. Nature wastes nothing.

Did you know that humans need more vitamins now than they did decades ago? That’s because our soil has lost nutrients. It’s time to put these nutrients back — and not with chemicals, but with organic matter.

Climate change is real. Carbon in the air is a problem. But carbon in the soil? That’s the solution.

Healthy soil pulls carbon from the air and locks it underground. It feeds our plants. It gives us nutrient-rich food. It holds water, prevents erosion, and helps us fight floods and drought.

Let’s respect the soil. Let’s heal it. What can you do today? Here are some examples:

– Start composting.

– Cover exposed soil with mulch and cover cropping.

– Avoid chemical fertilizers and pesticides.

– Reduce, reuse, and recycle water and electricity.

– Plant, plant, plant! Plant native trees like bamboos.

So, the next time you look down at the ground, don’t just see dirt — see hope. See a solution. See life. Healthy soil makes plants healthy. It leads to healthy people and a healthy planet!

Flor G. Tarriela is a banker by profession and an environmentalist/ gardener.