How Improved Soil Health Can Mitigate Climate Change
Earth’s ecosystems depend on soil. It hosts essential microorganisms, filters rainwater, stores organic carbon, and allows us to grow and harvest crops. But rapid soil degradation is making healthy topsoil increasingly scarce. According to the World Wildlife Fund, half of the topsoil on the planet has been lost in the last 150 years. And while estimates for the rate of soil degradation vary, a report from the Save Soil movement estimates that 95% of the world’land will be degraded by 2050.
Sustainable farming methods can not only improve soil health but also strengthen our chances of combating climate change. Here, we’ll review soil’s role in carbon sequestration, what causes soil degradation, and how regenerative agriculture can help us replenish our soils.
Soil’s Role in Carbon Sequestration
To understand how soil health impacts climate change, we have to start with carbon dioxide—the greenhouse gas produced by burning fossil fuels, powering transportation, and other natural and human activities. When released, carbon dioxide traps heat in the atmosphere, which then accumulates and contributes to global warming.
Defined as the process of capturing and storing carbon dioxide, carbon sequestration is an approach designed to decrease warming and climate change. There are two main types of carbon sequestration: biological, which involves storing carbon dioxide in forests, soils, and oceans, and geological, which involves storing it in geologic formations. There is also technological carbon sequestration, which researchers use to capture carbon dioxide in engineering and technological materials.
Plants naturally store carbon dioxide during photosynthesis, either in the form of soil organic carbon (SOC) or carbonates. Both prevent global warming contributions and benefit plant life. Carbonates, in particular, can mix with other minerals in the soil and stay stored for more than 70,000 years.
Unfortunately, carbon sequestered in soils is disrupted by aggressive agricultural practices, among other causes, and investment in carbon sequestration techniques is needed now more than ever. According to a 2017 study, “116 billion tons of carbon have been lost” since humans first began plowing land 12,000 years ago, Science reported. And worldwide issues caused by soil degradation continue.
The Causes of Soil Degradation
The Food and Agriculture Organization (FAO) defines soil degradation as a “change in the soil health status resulting in a diminished capacity of the ecosystem to provide goods and services for its beneficiaries.” The United Nations Office for Disaster Risk Reduction (UNDRR) provides its own scientific description, stating soil degradation is “a result of changes in physical, chemical and biological condition[s] that affect the soil's capacity to function as a vital living system and to provide ecosystem services.”
There are several specific causes of soil degradation, many of which we can control through sustainable farming practices that promote carbon sequestration. ● Industrial Agriculture Practices: Aggressive farming methods may yield short-term benefits but ultimately deplete soils in the long run. Particular methods include:
Monocropping: This is the practice of growing a single crop on the same land year after year.
Overreliance on synthetic fertilizers: While fertilizers can replenish soils in need of nutrients, research has shown that excessive synthetic fertilizer use has decreased the soil’s microorganisms.
Heavy tillage: Intense tilling practices at the industrial level can lead to soil compaction.
Deforestation: Defined as the intentional clearing of forested land, deforestation is usually implemented to make space for industrial and other non-natural development.
Overgrazing: Overgrazing is the depletion of vegetation cover and increased ground compaction from extensive periods of livestock grazing.
Pesticides and Pollution: Overuse of pesticides and other agrochemicals damages soil composition over time. Other sources of pollution include industrial spills, mining, agricultural runoff, and more.
Natural Erosion: Essential topsoil can be lost due to water erosion, caused by poor drainage, or wind erosion, when soil is blown away.
Impacts of Soil Degradation
The impacts of soil degradation can be felt not only on farms but everywhere—particularly when considering its tremendous impact on global warming and climate change. Damage to our soils has a domino effect that can lead to losses in food, microorganisms, farming resources, and arable land. Here are some of the significant impacts:
Poor Soil Quality: Soil health can decline in several ways:
Loss of Organic Matter: Organic matter is crucial to optimal soil health, and its loss destabilizes the soil.
Loss of Biodiversity: With the loss of organic matter comes a loss of the microorganisms that depend on a healthy soil environment.
Salinization: Salt content increases to dangerous levels when salts build in the plant root zone due to watering or drainage issues.
Compaction: Soils that are too dense due to compaction prevent plant roots from sprouting.
Acidification: Increased acidity and decreased soil pH can also harm microorganisms. Soil acidification is usually caused by inappropriate crop or fertilizer selection.
Desertification: Desertification is the deterioration of land quality, often caused by climate change and erosion, and leading to the loss of arable land.
Increased Flooding: If soil cannot absorb water, there is a greater chance of rainwater flowing into bodies of water, leading to floods.
Regenerative Agriculture and Soil Health
There are no quick fixes to a problem as large as soil degradation. However, regenerative agricultural practices have been proven to restore soil health over time.
Regenerative agriculture is not a new concept, as the Noble Research Institute notes; it is a traditional practice and mindset that closely aligns with the soil’s natural processes. The results combat soil degradation, in turn increasing organic matter and soil productivity.
Here are some more sustainable farming methods that fall under regenerative agriculture:
Reduced or No-Till Farming: No-till farming keeps soil intact and carbon stored within the soil. Minimal soil disruption through no-till farming can improve soil health and reduce fuel use for equipment.
Cover Crops: Cover crops are used for soil enrichment, covering the ground, and increasing organic matter and biodiversity.
Crop Rotation: Planting different types of crops on the same land over a period of time improves nutrient content in soil and prevents pests and weeds from taking over the land.
Decreased Use of Fertilizers or Pesticides: In addition to reducing the use of fertilizers and pesticides, farmers should choose their products wisely. Organic fertilizers are healthier than synthetic ones.
Adaptive Grazing: To avoid overgrazing, farmers control where and for how long livestock graze in a given area. Rotating grazing animals prevents intensive soil disruption, which in turn keeps carbon sequestered.
How to Support Sustainable Farming Practices
You may be wondering what you can do now that you are armed with information about soil health, soil degradation, and regenerative farming. One of the most effective ways to promote sustainable farming practices is to continually educate yourself and others about the dangers of soil health depletion. You can choose to support organizations dedicated to sustainable practices, such as the Rodale Institute and Regenerative Agriculture Foundation.
Shopping local and buying from farmers’ markets allows you not only to connect with your local community but also to learn about the practices on small-scale farms.
Finally, if you are a farmer or a backyard gardener, consider adopting regenerative practices as you grow your own food. Your soil will thank you.