By Jamie Martin
Cover crops play an important role in protecting farmland during months when major crops are not growing. They reduce erosion, help the soil hold water, improve soil structure, support nutrient cycling, and suppress weeds. They can even offer habitat for beneficial insects and provide feed for livestock.
To manage these crops well, scientists and farmers need accurate temperature data to predict how they grow. Until recently, many cover crop species did not have well-documented temperature limits.
A research team from the University of Arkansas System Division of Agriculture studied eight common cover crops to determine their “cardinal temperatures.” These include base, optimal, and maximum temperatures. The base temperature is the lowest point where a plant can still grow. The optimal range supports the highest growth rate, and the maximum temperature is where growth stops due to heat.
The study examined crimson clover, Austrian winter pea, balansa clover, barley, black-seeded oats, common vetch, cereal rye, and hairy vetch. Researchers identified 14 new temperature values and found several differences compared to older scientific records. One important change was the base temperature for cereal rye, which was discovered to be nearly 9°C lower than what earlier studies reported. Using the old values would have caused major errors in predicting how fast rye grows.
Because the growth chamber used in the study reached a limit of 34°C, maximum temperatures for some crops had to be estimated. Still, these values are especially important for farmers in warmer southern regions where spring temperatures rise quickly.
The project was led by researcher Mila Pessotto as part of her master's work. Her findings helped refine or define 18 of the 24 temperature values studied and earned her the 2025 Outstanding Paper Award from major agricultural science societies. The research was supported by commodity boards representing corn, grain sorghum, and soybeans.
These updated temperature values will help scientists create better crop models, improve nutrient cycling predictions, and give farmers clearer information for managing cover crops effectively.
Photo Credit: gettyimages-eugenesergeev
Categories: National