Adjusting Forage Management for Summer Heat July 18, 2017
The current heat wave is taking a toll on forage plants, particularly cool-season plants. Alfalfa and clovers, bromegrass, orchardgrass, fescues, needlegrasses, and wheatgrasses all struggle during hot weather, but adjusting your management can limit the stress from stressful weather.
If you’re old enough, do you remember – before air conditioning – how drained you used to feel after spending a night when the temperature never dropped below 80? The same thing happens to cool-season forages, resulting in very slow growth, lower forage quality as plants burn up the good nutrients, and limited recovery of root reserves after defoliation. And if it also is dry these conditions can even become deadly.
Warm-season grasses are just the opposite. Millet, sudangrass, sorghums, and our native bluestems, gramas, switchgrass, and other warm-season grasses thrive when the temperature is around 90°F. Their metabolism runs at peak efficiency when it is hot so they grow rapidly while maintaining reasonable forage quality and good root growth.
This is assuming these plants have adequate moisture. Once they dry up, these grasses will overheat too, just like cool-season grasses do at lower temperatures.
As you graze or hay, be aware of the stress that high temperatures put on your forage. Allow plants to recover for a longer time before the next use and don’t expect high feed values or good animal gains when the nutritional goodies are burned right out of the plants.