Today it’s almost impossible to turn on the television, browse the web, or read the newspaper without stumbling over the topic of climate change. Many scientists believe the answer to climate change is buried in the soil—could the solution be right beneath our feet?
Most of us know by now that science has identified certain molecules in the air which cause the atmosphere to hold heat (aka greenhouse gases), and that the largest overall contributor to climate change is carbon dioxide (CO2). We’ve surpassed what many believe to be a sustainable threshold of CO2 in our atmosphere. The question is: What solutions are available to help reduce carbon dioxide levels and help get the world back to a “safe” level?
What does soil have to do with all of this? Soil has the ability to hold large amounts of carbon for very long periods of time. An article by Yale University states there, “More carbon resides in soil than in the atmosphere and all plant life combined.” In a process known at the carbon cycle, plants take in carbon dioxide. After a plant dies, carbon is returned to the soil as it decomposes.
Over the last century, humans increasingly worked the soil to the point of depletion, which resulted in large amounts of carbon released into the atmosphere. Soils have lost an estimated 50 to 70 percent of their original carbon. Poor agricultural practices such as intensive tilling of farmland and over-grazing are major contributors to the loss of soil organic matter worldwide.
As destructive as agriculture can be if done irresponsibly, when done well, it has the potential to be a solution to climate change. For example, well-managed grasslands have been proven to be “carbon sinks” (a natural environment that absorbs carbon dioxide from the atmosphere). Areas managed as perennial grasslands or grazed pastures are less prone to soil erosion and build up soil organic matter, whereas annual, mono-cropping systems never replace the carbon they take out.
Grazing animals, such as cattle help promote new growth in pastures by recycling their carbon-rich food (grass) into nutrient-dense manure, which becomes a fertilizer when the animals “spread” it out in the field. Some farmers mimic nature by using rotational grazing programs in which they move cattle to and from small sections of the pasture. Researchers have found that this practice improves grassland productivity, increases soil carbon, and even reverses the adverse effects of desertification (the transition of productive soils into deserts).
Farmers can also increase carbon in the soil by planting cover crops to replenish the soil after harvesting annual crops like corn or soybeans, and reducing the number of times they cultivate (or till) fields. Excessive cultivation using heavy equipment disturbs the soil more than is often necessary, thus increasing loss of carbon. However, grassland management reduces the amount of carbon released in the atmosphere and increases the amount of carbon returned to the soil.
Soil carbon is extremely beneficial to farm productivity, but also to society and nature as well. Carbon rich soils are less prone to runoff, have increased ability to hold water in periods of drought, and the benefits of healthy soil goes on. Most importantly, soil is a readily abundant resource that, when properly managed, is a key component in addressing the issue of climate change. If we improve upon our land practices we could help balance the carbon levels in our atmosphere, making the earth a “cooler” place to live.
Maybe it’s time we stop treating our soils like dirt.