Growing cover crops is not a passive practice.
That was the message that Dr. Marcelo Wallau, forage Extension specialist with the University of Florida’s Institute of Food & Agricultural Sciences, aimed to drive home during his presentation at the 2024 American Forage & Grassland Council’s annual conference.
Cover crops – or winter forages, as Country Folks columnist Paris Reidhead prefers they be called – are plants grown to improve soil health and benefit other crops. However, Wallau still sees a lot of farmers not utilizing the practice of growing cover crops because he believes “a lot of ‘it doesn’t work’ turns into not using it.”
So how do we make it work better? Wallau said the production of row crops is usually better when integrated with grazing (where it makes sense to do so). “If I treat my cover crop as a crop, I get a lot more benefit out of it,” he said.
One big bonus of using both cover crops and livestock grazing? “There’s much less nitrogen leaching … and that’s very good for my pocket,” he said.
But not all grazing is good grazing. Wallau emphasized that moderate grazing can extend the growing period at the end of the season, with more forage and more carbon being stored in the ground.
Dr. Marcelo Wallau
The math is simple. Better pasture = better cattle, Wallau said. He cited a study done in 2020 that looked at an integrated crop/livestock system. Whole-system fertilization can increase total forage production by 36% and crop yield by 13%.
Grazing contributes to improvements in soil chemical quality in no-till systems too. Wallau said if there’s no grazing, soil pH increases only reach about three inches deep and base saturation only reaches three inches. With moderate grazing, pH improvements can go eight inches deep and base saturation can go as far down as 16 inches.
But what about soil compaction when grazing cover crops? Some studies show a small increase in compaction, but these were on operations with high stocking rates, high utilization and low stubble/residual growth.
“Harvesting more doesn’t mean higher efficiency in grazing – let the pasture grow!” Wallau said.
In general, there will be some slight compaction on the surface layer but research has shown no reduction on grain yields resulting from this.
Interested in planning and managing grazing in your cover crops? Wallau said to look at three things:
- Grazing intensity and your forage allowance, stocking rate and canopy height
- Grazing frequency and your stocking method, days between grazing events and length of utilization
- Timing of grazing and your days after planting and plant maturity
This all circles back to the concept that growing cover crops is not a passive practice. You plant them and eventually you’ll either cut them for forage, till them in as green manure or – as Wallau suggests – with proper management, you can let your livestock graze them.
by Courtney Llewellyn
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