Ohio’s southeastern region has been hit hard by drought this summer, with pastures and hayfields showing significant damage. At this point, many fields are in poor or very poor condition, with slow to no plant growth due to dry conditions and higher-than-normal temperatures.
Even with excellent management practices, drought conditions will cause visible damage to fields well into the fall season.
One of the emerging concerns from this summer’s drought is potential toxicity developing in forages. For example, the risk of prussic acid poisoning has increased with the severe drought conditions in stands containing Johnson grass, sudangrass and sorghum-sudangrass, even though this condition is typically associated with frost or nitrogen applications.
Many forage and weed species can also accumulate nitrates, which can be deadly for some livestock. When in doubt about toxicity, submit forage samples for testing — many labs offer this service.
Measure pasture recovery following a drought by monitoring stand density and height of plants. There are several methods to evaluate a stand, including measuring forage height, clipping and weighing forages, and utilizing a grazing stick or rising plate meter. In general, thick and tall stands are good indicators of a quickly recovering pasture.
When pasture stands are only slightly affected by drought and contain more than 70% of their original height and density, the stand is still considered functional and is likely to recover quickly with continued management.
In contrast, if a stand is operating well below its usual capacity, recovery will require time and patience. Overgrazed (sometimes unavoidable during drought years) and overstocked pastures will struggle more than those with managed grazing at the appropriate stocking density.
Forages grazed too short will have a more difficult time recovering, reducing stand density and height and leading to an increase in weed pressure.
You should approach the management of overgrazed pastures as you would a newly established field. Begin by conducting a soil test and applying amendments based on the results. This practice will provide the desired plants with the best possible start, enhancing their chances of successful reestablishment.
Fields low in phosphorus will benefit from P applications since phosphorus is important for cell division, plant tissue growth and, subsequently, root growth and development.
Weed control is crucial in these recovering pastures and should be implemented aggressively and in a timely manner. If left unchecked, weeds can quickly dominate a field due to the reduced competition from weakened forages.
For effective weed management, use post-emergent herbicides labeled for use on pastures. It’s important to apply these herbicides when weeds are still small and actively growing.
Waiting until weeds have gone to seed significantly reduces the effectiveness of control measures and can exacerbate the problem in subsequent growing seasons.
If stands appear thin, it may be beneficial to consider frost seeding clover this winter to prevent weeds from taking over.
By addressing weed issues promptly, you create a more favorable environment for the recovery and growth of desirable forage species in your pastures.
Keep in mind, you can do everything right, but if rainfall continues to be less than adequate, expect recovery to be minimal.
According to National Oceanic and Atmospheric Administration, fall is predicted to be warmer-than-average September through November, with equal chances of above or below-normal precipitation levels across Ohio. So, it’s hard to tell at this point how much longer these dry conditions will last.
