NCAR Study Finds Cover Crops Can Heat Up Surrounding Atmosphere
Cover crops — plants that are grown in order to nourish and protect soil during the winter that provide a host of benefits to farmers and the environment — have a downside. A new study shows the crops can heat up the surrounding atmosphere.
Cover crops “create a darker surface than a snow-covered field, absorbing more heat from the sun and producing a local warming effect,” according to a news release from the National Center for Atmospheric Research and the University Corporation for Atmospheric Research. The release highlighted the results of an NCAR study recently published in the journal Geophysical Research Letters .
The findings stand in contrast to the many benefits of cover crops, which have been shown to improve the nutrient density of soil, prevent erosion and even help to reverse the effects of climate change by capturing and storing carbon in the earth.
David Lawrence, a scientist at NCAR and co-author of the study, said the findings emphasize the unforeseen consequences of land management techniques.
He said that with the study, scientists were trying to “get a bit more attention to the fact that you do need to consider this full cycle of consequences.”
But while the research provides valuable perspective on the practice of planting cover crops, according to Lawrence, more detailed analysis and research must be performed before policy decisions can be made.
“It’s premature for that,” he said. “You’d want to do this with more models and more detailed models, and accounting for some of the details about cover crops that are very broad-brush in our study.”
Gordon Bonan, a NCAR senior scientist and another co-author of the study, said it highlights the other effects plants can have on the environment.
“In this case what we saw was if cover crops are really good for fertility and productivity and even carbon storage, they could have this detrimental effect of warming the wintertime climate,” he said.
The study, performed using the Community Earth System Model, a computer model created by NCAR for the purpose of researching the Earth’s atmosphere, observed the effects of cover crops with three different sets of characteristics.
Tall and leafy plants, tall plants with sparse leaves and short and leafy plants were all tested under conditions found in the central and northern United States and southern Canada.
After running the simulation, NCAR scientists concluded that, while all three plant types warmed the atmosphere, tall and leafy plants produced the most significant effect, heating up the surrounding area by almost 5.5 degrees Fahrenheit.
“When the crop went from 10 centimeters up to 50 centimeters, that’s when we saw a really big impact,” said Danica Lombardozzi, a plant ecologist at NCAR who co-authored the study.
She also said that leafiness was a big factor, but “the crop height is really what had the biggest impact, because that determined whether or not it was sticking up above the snow.”