Cover crops help moderate soil temperature

The quality of soil is an incredibly important factor in the sustained, healthy growth of our crops. Soil quality can make or break a farmer’s crop yield and the very value of the land it sits on. Characteristics such as the content of organic matter and the moisture of the soil play vital roles in helping plants grow. Now, researchers have found that soil temperature is also of the utmost importance.

Plants rely on certain consistent soil temperatures in order to grow. “Most plants are sensitive to extreme changes in soil temperature,” says Samuel Haruna, a researcher at Middle Tennessee State University. “You don’t want it to change too quickly because the plants can’t cope with it.”

The ability of soil to buffer against temperature change is dependent on a variety of factors. How much the soil is compacted is just one of those factors.

Compacted soil actually causes the soil particles to transfer temperatures much faster, thus increasing temperature change. This can be caused by farmers dragging heavy machinery over the soil – which must happen often, as you can imagine. However, research has shown that cover crops and perennial biofuel crops help relieve soil compaction and moderate temperature.

Haruna set out to determine if these cover crops and perennial biofuel crops could also help soils protect themselves against fluctuating temperatures. He and a team of researchers grew multiple types of these crops in the field and then tested the soil in the lab for its ability to regulate temperature.

“I was amazed at the results,” says Haruna. The team found that both cover crops and perennial biofuel crops help soils become better buffers against extreme temperatures by slowing down how quickly temperatures spread through the soil. The roots of these crops break up the soil, preventing soil molecules from clumping together and compacting. These roots also add organic matter to the soil, which is an additional benefit in temperature regulation.

Furthermore, perennial biofuel and cover crops help soil retain moisture, which keeps soils from heating up too quickly as water itself is a heat buffer.

“Water generally has a high ability to buffer against temperature changes,” explains Haruna. “So if soil has a high water content it has a greater ability to protect the soil.” 

Major temperature fluctuations are in our future as climate change becomes more prominent around the world. Haruna believes that increasing the use of cover crops may help to lessen the effects of climate change on soil quality and ultimately crop production. He looks to continue this research with more field experiments in the future.

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By Connor Ertz, Earth.com Staff Writer