Today let's play a little game of 'what if'. As in 'what if it rains'? What if your pastures and hay meadows green up and grow. Should you graze? Will you succumb to the temptation?
As tempting as it may be to give your animals some nice green grass, resist that temptation. If you do graze, it might do more harm to your grass than if it did not rain at all.
How can that be? To understand this risk, we need to review what happens when a dormant plant starts to grow. When a dormant plant starts to green up and grow, like in the spring following winter or after a rain during a drought, the plant mobilizes nutrients from its root system to energize the initial growth. This process actually weakens the root system and the plant temporarily. As the plant grows and produces more leaves, those leaves eventually harvest enough sunlight energy to replace the nutrients used during the green up process.
However, if some of the leaves are removed by grazing before they replace the nutrients used during green up, the plant will try to mobilize even more root nutrients to restart the process. At this time of year though (going into fall), the plant actually needs to increase root nutrients for winter survival. If grazing prevents that from happening, plants will go into winter in a very weakened condition. Some may die. And those that survive to next spring will grow very slowly until they have recovered from the multiple stresses of drought and untimely grazing.
So do yourself and your pastures a favor. Decide right now that no matter what happens this fall, you will not graze green growth again until next year. Pasture survival may depend on it.
Mark Sulc adds the following note: In Ohio, we probably would be OK to top graze tall fescue pastures late in the fall IF they have been actively growing for at least 5 weeks after release from drought stress. If at least 5 to 6 weeks of active growth has occurred, the plants will probably have accumulated sufficient energy reserves for winter survival and spring regrowth. But if the pasture is weak and continues in drought stress well into the fall, following Dr. Anderson's advice will improve persistence and pasture vigor next year. It's tough, but take the long view on this one, or you may have a worse situation next year.