Q: We often hear about business practices that are negatively affecting our environment. What can horse farms (private and commercial) do that might have a positive impact on the environment?

A: Scientists primarily attribute climate change, or the ongoing increase in average global temperatures, to an increase in carbon dioxide (CO₂) in the atmosphere, but how do horses and horsekeeping contribute? The burning of fossil fuels stands as a leading cause of increased CO₂ in the atmostphere , but many agricultural practices also increase the amount of greenhouse gases accumulating in earth’s lower atmosphere.

The carbon cycle is nature’s way of reusing carbon. Carbon travels from the atmosphere into organisms on Earth and then back into the atmosphere repeatedly. Experts recommend reducing the burning of fossil fuels and actively removing some of the CO₂ in the air to mitigate climate change. This is where horse owners with pastures can assist.

The Role of Photosynthesis in Horse Pastures

As part of photosynthesis, all plants pull carbon dioxide out of the atmosphere and use it to manufacture their food. In a process called carbon sequestration, plants store CO₂ in the form of sugars, in stems, leaves, and roots; natural areas that utilize CO₂ from the atmosphere are called carbon sinks.  A productive, grassy pasture with at least three to four inches of plant growth acts as a carbon sink, pulling the harmful CO₂ out of the atmosphere.

When horses overgraze a pasture, chomping grass plants down to soil level, the plants can no longer photosynthesize and take in carbon from the atmosphere. In fact, an overgrazed pasture with bare soil releases carbon back into the air. If the amount of carbon the plants and soil release is greater than what the plants can capture through photosynthesis, then the pasture system loses carbon to the air, becoming a carbon source.

Take-Home Message

When owners manage horses properly on grassy pastures, the leafy grass plants remove carbon dioxide from the atmosphere and sequester it in their roots. Ensure healthy pastures by avoiding overgrazing, mowing consistently to reduce weeds and encourage healthy grass growth, and testing the soil to confirm it can support healthy pasture growth. Soil in well-managed pastures contains greater organic material (from manure and urine) and therefore offers a more stable, sustainable soil community of beneficial insects and microbial life. That in turn creates climate-friendly, resilient horse pastures that can help fight climate change by sequestering atmospheric CO₂ to manufacture more food for pasture plants.