Seeding cover crops to protect your soils, fix nutrients and extend your grazing program is the right thing to do. As a publication we do our best to highlight the value of cover crops as a management tool, while being realistic about the learning curve involved in their adoption.
Still, I like to scan the headlines of various publications to see what they say about cover crops, as adoption of covers is still a major challenge in the U.S. This week I was left shaking my head: On a single Google search result I found two articles that contradict each other about the effect cover crops supposedly have on the environment:
- The National Center for Atmospheric Research (NCAR) says cover crops, despite their soil-building qualities, may be warming winter air temperatures as they absorb sunlight, at least in the area they’re growing. Scientists used computer modeling to find that fields with crop cover showed significantly warmer winter temperatures than fields with no cover or just short stubble.
“On average, that increased air temperature by 5.5 F — a significant temperature rise,” says Danica Lombardozzi, a plant ecophysiologist with NCAR. The organization admits it’s new research and the applications for this data are limited, “but this localized warming could change anything from precipitation in the area, to increasing the melting time for snow cover in the fields.”
- A different study published in the journal Science Advances says “natural climate solutions” such as trees and cover crop seeding on farms could offset the equivalent of 21% of the U.S. net annual carbon emissions. Researchers say 63% of the potential natural climate-change mitigation would come from increasing the ability of plants to store carbon instead of it going into the air as a polluting greenhouse gas.
First off, one of the things I learned several years ago from a speaker at our National No-Tillage Conference is that estimating the soil organic carbon sequestration abilities of soils and plants is not an exact science, and many studies of this topic have significant flaws.
More importantly, how can it be possible that seeding cover crops is both good and bad for the atmosphere?
Should no-tillers in the southern Plains ignore the moisture-saving, soil-cooling benefits of a cover crop canopy and let their soils be fried by the sun? And do you think no-tillers in the northern Plains are going to complain about a little more moisture and warmth in their fields during the winter as they look ahead to spring seeding?
What’s most important is managing your farm operation more sustainably and profitably, and cover crops are, or can be, a major part of that — along with low- or zero-disturbance no-till and proper grazing methods.
Managing no-till to please every environmental group or respond to every newfangled study is a no-win situation. It’s all about what works on your farm. Period.
