Little to no change in grain moisture, increased stalk rots and yield loss prove disadvantages with delayed harvest

New research from Ohio State University concludes that yield losses and stalk rot are greatly increased when harvest is delayed. The research also confirms that delayed harvest, after mid-November, does little to reduce grain moisture.

"With the increase of farm size and more acres to manage, growers need to know when harvest delays begin to affect yield and by how much," says Tom Doerge, Pioneer Hi-Bred International, Inc., agronomy research manager. "Farming is a balancing act, and this research confirms there are few advantages, and likely disadvantages, to delaying harvest. Research shows growers should target early October through mid-November for harvest."

Pioneer sponsored the research through the company's Crop Management Research Award Program.

Harvest delays impact yield

The research conducted by Ohio State University evaluated four hybrids at three different locations. Four Pioneer® brand corn hybrids were planted at four plant populations – 24,000, 30,000, 36,000 and 42,000 plants per acre – for three years. Plots were harvested on three dates – early to mid-October, early to mid-November and on or after mid-December.

The research found there was an 11 percent decrease in yields between mid-November and mid-December. There was only a 2 percent decrease in yield from mid-October to mid-November.

"We also found yield losses caused by harvest delays were greater at the two higher plant populations, 36,000 and 42,000 plants per acre," says Peter Thomison, corn cropping systems extension specialist for Ohio State University. "Yields decreased by 15 percent and 18 percent from early to mid-October and mid-December."

Stalk scores prove to be useful

Harvest delays did result in increased stalk rot and lodging. The greatest increase in stalk rot – 40 percent – occurred between early to mid-October and early to mid-November, whereas the greatest increase in stalk lodging occurred after mid-November.

"This research concluded there is a delay in stalk lodging, although stalk rot may have occurred earlier in the fall," says Doerge. "This research also confirmed stalk scores associated with hybrids are an effective tool. Growers should keep stalk scores in mind when staging the harvest of their fields and harvest the ones with lower stalk score hybrids first."

Don't delay harvest to improve grain moisture

With higher energy costs, growers may delay harvest to wait for additional grain drydown. Grain moisture, averaged across site years, hybrid and plant population decreased 6.3 percent from early October to on or after mid-December. Most notably, the majority of that decrease came between mid-October and early November – 5.8 percent.

"After mid-November there is little advantage to delaying harvest to improve grain moisture content," says Thomison. "Growers who plan to rely on field drying or expect some of their distant fields will be harvested late, should only plant hybrids with good disease resistance and stalk quality to minimize potential grain losses associated with harvest delays."

They also should carefully consider recommended hybrid seeding rates and avoid final populations exceeding 30,000 plants per acre to limit stalk lodging, adds Thomison.

This research into the impact of delayed harvest is one of 14 research projects funded by Pioneer through its Crop Management Research Awards Program. Each year Pioneer awards more than $100,000 in research funds to scientists at universities or other institutions in the United States and Canada. Each research project is focused on finding more cost-effective, technologically advanced and environmentally friendly ways to produce and manage crops.

Pioneer Hi-Bred International, Inc., a subsidiary of DuPont, is the world’s leading source of customized solutions for farmers, livestock producers and grain and oilseed processors. With headquarters in Des Moines, Iowa, Pioneer provides access to advanced plant genetics, crop protection solutions and quality crop systems to customers in nearly 70 countries. DuPont is a science company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 70 countries, DuPont offers a wide range of innovative products and services for markets including agriculture, nutrition, electronics, communications, safety and protection, home and construction, transportation and apparel.

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