Study finds key temperature limits to improve cover crop management
Understanding how temperature affects plant growth is important in agriculture, especially for cover crops grown between major planting seasons. These crops protect the soil from erosion, improve moisture retention, add nutrients, support soil structure, and help suppress weeds. They also provide habitat for insects and can be used as livestock forage.
However, accurate temperature limits for many cover crops were not known earlier, making it difficult for scientists to create reliable growth models.
Researchers from the University of Arkansas System Division of Agriculture, led by soil fertility expert Dr. Trent Roberts, studied eight widely used cover crops to identify their “cardinal temperatures.” These include the base temperature, where growth begins; the optimal temperature, where growth is fastest; and the maximum temperature, where growth stops due to heat.
The team used controlled growth chambers to test plants such as crimson clover, Austrian winter pea, balansa clover, barley, black-seeded oats, common vetch, cereal rye, and hairy vetch. They recorded 14 newly identified cardinal temperatures, including several values that were different from earlier published data. For example, the base temperature for cereal rye was almost 9°C lower than what scientific literature previously reported. This finding is important because incorrect values can cause major errors in predicting plant growth.
Some maximum temperatures had to be estimated due to chamber limits, but these values remain useful for regions like the Mid-South and Southern states, where temperatures may rise quickly in late winter and early spring.
The research, led by scientist Mila Pessotto during her master’s program, refined or identified 18 out of 24 possible temperature values. Her work earned the 2025 Outstanding Paper Award from the Tri Societies for agronomy, crop science, and soil science. The project was supported by the Arkansas Corn and Grain Sorghum Board and the Arkansas Soybean Promotion Board.
This study marks an important step toward better growth modeling, improved nutrient cycling estimates, and stronger decision-making tools for farmers using cover crops.
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