What Is Healthy Soil Made of, Its Importance as a Carbon Sink and More
We’re all aware of the overload of carbon dioxide accumulating in Earth’s atmosphere. Largely due to man-made actions, carbon dioxide is one of the many greenhouse gases that influence the climate patterns around the world. While the oceans do absorb huge amounts of carbon – leading to dangerous ocean acidification – there’s another solution to some of our problems. Did you know that healthy soil could become an efficient carbon sink, as well?
What Is Healthy Soil Made of?
Soil is not just ‘dirt,’ as some tend to think. It’s comprised of water, minerals, organic matter, and air. The result is a vital living ecosystem with crucial influences on plant, animal, and human survival. This ecosystem includes bacteria, fungi, mites, plant roots, algae, worms, insects, and larger animals. Additional organisms are always at work so we can have clean air and clean water, as well as food, forests, diverse wildlife, and beautiful scenery.
Healthy soil can do all this by assisting plant and animal life, regulating water, filtering potential pollutants, absorbing and releasing nutrients (including carbon and nitrogen), and providing support and stability for plant roots and human structures. Therefore, we can define healthy soil as a blend of minerals, rock, water, air, organic matter, microorganisms, including an array of insects and worms. This intricate network is vital for constantly replenishing the soil and supporting long-term soil fertility.
Improving Degraded Soils
As climate science advances, it reveals more and more about the power of carbon sinks. And soil can do just as much as forests and oceans when it comes to carbon storage – that is, if they are healthy. So, we could all be a little more interested in the dirt in our gardens and backyards.
According to Rattan Lal, Director of Ohio State University’s Carbon Management and Sequestration Center, we have already lost 50 to 70 percent of the original carbon stock of the world’s cultivated soils. Much of it has become CO2 as it oxidized upon air exposure. However, the good news is that we can fix this!
We need to improve the degraded soils, including those overgrazed or mono-cropped. Soils which have suffered chemical-intensive agriculture for decades are in dire need of human-assisted improvement. Several regenerative practices could help soils regain their natural powers. Composting, for example, as well as planting cover crops to create green manure. Experts also encourage more permaculture practices and using soil amendments like bio char.
However, it’s also of massive importance that we ensure existing carbon sinks like rainforests and peatlands remain intact. Degrading them any further will only leak even more carbon into the atmosphere.
What’s the Solution?
The National Environmental Education & Training Foundation (NEEF) believes there is a lot of room for improvement. On several occasions, they have stressed the importance of the connection between a healthy soil and the ultimate future of our planet. Extreme climate changes may lower the favorable aspects of soil. The changes translate into raised occurrences of wildfires, severe precipitation, prolonged drought, polar ice caps melting, and extreme heat.
- Wildfires often heat the soil so much that they alters its chemical, physical, and biological abilities.
- Droughts suck the life out of soils by lowering the amount of water necessary for sustaining life in the ecosystem.
- Severe precipitation events lead to soil erosion. This, in turn, causes soils to leak into nearby water bodies, becoming useless for crop growth support.
- Extreme heat boosts the rate of organic matter’s decomposition in soil, which then maximizes the amount of CO2 discharged into the atmosphere.
Soil as Carbon Sink
All the soils in the world contain around 2000 billion tons of carbon in various forms at any time. About 300 billion of those tons exist as detritus in the top soil. This carbon-rich material decomposes at fluctuating rates, depending on various factors, including temperature and soil health. Ecological Society of America presents the environmental issue of carbon sequestration in soils in a comprehensive manner; check out the information they provide here.
Man’s abusive use of agricultural soils has led to massive losses in the worldwide soil carbon sink. Ploughing and other soil disturbances can cause accelerated respiration and the release of large amounts of soil carbon. In the absence of harsh soil treatments, this carbon would decompose a lot more slowly.
The key to balancing the soil carbon storage is employing more sensitive land-use practices. Allowing the soil to recapture its properties might reverse recent trends of substantial loss of carbon from soils. Sustainable farming practices have become more popular in the past few years. “No-till,” for example, encourages farmers to use agricultural land without the soil disturbance and carbon loss caused by ploughing.
Improving Soil Health
Farmers and gardeners can learn to improve even the very poor soil. With their roots in healthy soil, plants and crops grow more productive and more vigorous. Here are some tips that can lead to improved soil.
- Sandy Soil – In sandy soils, the large, irregularly shaped bits of rock allow for large air spaces between the sand particles. This means the water drains rather quickly, draining the nutrients away, too. This often takes place before plants even have a chance to absorb them. What can you do? Add mulch, wood chips, bark, leaves, hay or straw around your plants. This will help retain moisture in the soil.
- Clay Soil – Clay particles are small and tend to pack together too tightly. Therefore, there is hardly any pore space at all for air and water. Wet clay soils are sticky and unworkable because they stay waterlogged for too long. What can you do? Add 2-3 inches of organic matter into the surface of the soil (add it in the fall, if possible). Use raised beds to help with drainage and don’t step in the growing areas.
- Silty Soil – They contain small particles of weathered rock, which means they are rather dense and have poor drainage and poor aeration. However, they are more fertile than either clayey or sandy soils. What can you do? Prevent soil compaction by skipping unnecessary tilling and minimizing foot traffic on garden beds. Consider investing or building raised beds.
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