To get a handle on soil erosion while increasing organic matter, producers will often look to the use of cover crops to lock in moisture and maintain a healthy environment.
In a recent study by the Agricultural Research Service (ARS) through the United States Department of Agriculture, producers can take advantage of cover crops for moderate grazing by cattle, while leaving the organic matter within soil unharmed.
“Conventional wisdom holds that grazing would remove the nitrogen and carbon otherwise left on the soil in the cover crop plant residue,” states the ARS research report. “Allowing cattle to tread on the soil could also compact it, preventing air and water from passing through the soil to reach plant roots. But if grazing wouldn’t harm the soil, it might encourage more growers to try using cover crops.
According to the report, the seven-year study was the first of its kind to be conducted in northeast Georgia to assess soils primarily found in the southeast part of the United States in the Piedmont region. Lead researcher, Alan Franzluebbers, ARS ecologist from the Plant Science Research Unit in Raleigh, N.C., set up a model that stocked cow-calf pairs four acres/head, on a variety of no-tilled and tilled cover crops planted during the off-season for winter and summer grains. Soil samples were collected a depths of one foot.
“The results showed that the relatively low rate of grazing did not significantly affect the amount of organic matter in soil and did not cause soil compaction. Additional studies should be conducted to determine a stocking threshold that increases compaction,” the report says. “The findings also showed that cover crops make for high-quality forage. Organic matter lost by allowing cattle to graze on cover crops is likely made up in the organic input from manure. As in previous studies, the team found that using no-till generally keeps more carbon and nitrogen in soil than using conventional tillage.”