If one word could be used to characterize the 2019 season, the label would be stressful. The types of stress from field to field include water stress, which leads to nitrogen loss and then fertility stress.
Then there’s compaction stress that leads to issues with root development and root structure. Add overall plant health, variable maturity stages and insect pressure to the list of stressors and you’ll see there are several issues that can negatively impact yield potential.
If temperatures are high and moisture is limited following pollination, yield loss during grain fill may be upwards of 3% to 5.8% per day of stress. Even with sufficient moisture, high temperatures can cause a high degree of stress on the corn plant and affect corn yield potential.
Iowa State University reports that a 1% corn yield loss can occur after four consecutive days of temperatures at 93 degrees or greater. A fifth day of high temperatures may cause another 2% yield loss, and on the sixth day another 4% reduction can be expected.
While higher overall temperatures are welcome to help push along a crop that is behind, excessive heat poses a near-term threat to yield potential.
There are few options to minimize heat stress during the grain fill stages, but growers can mitigate yield loss by planning ahead for adequate fertility to maintain late-season plant health and manage disease.
Disease occurrence varies greatly from season to season, and by the maturity stage the best option to preserve yield may be to apply a fungicide.
Through early September, farmers should closely monitor stressed fields for compromised stalk strength and adjust harvest schedules to first remove crops at high risk of stalk lodging.
Consult with your local Channel Seedsman about determining a harvest schedule for your fields. Visit Channel.com for more information.