A few key management decisions can be the difference between profits and losses for silage corn growers.
Quality, yield and profit depend on proper hybrid selection, planting date, plant density, soil fertility and pest control, says Joe Lauer, University of Wisconsin Extension corn agronomist.
“Growers doing a good job with all of these will maximize their yields,” he says. “But it can go the other way pretty quickly.”
The agronomist presented 17 years of corn silage data during a talk at World Dairy Expo.
Hybrid selection is the first and foremost factor growers should consider, he says. As breeders develop more hybrids and offer more choices, growers should be sure to select seed with high potential yield and quality.
“Don’t just let the company pick it for you,” he stresses. To find the best local option, Lauer suggests using performance data from the surrounding region and states, which can be found online from land-grant universities.
If selecting solely for silage, a grower should look for a hybrid with high forage yields and digestible stover. If the field may be harvested for grain, hybrids should deliver high grain and forage yields. Quality silage hybrids also have high grain yields, because the grain is highly digestible.
“You can swing yield 39% based on a decision you make at your kitchen table picking hybrids,” Lauer says.
Also pay attention to maturity. Silage hybrids can be about five to 10 days later than grain hybrids and typically yield more forage.
Lauer sifted through years of corn silage data to show how much yield differed between the best and worst performers in a variety of trials. The highest-yielding hybrid averaged 3.2 tons/acre more dry matter than the lowest-producing one, a 39% difference. The average difference in milk per acre was about 11,500 lbs between the highest- and lowest-yielding hybrids.
Planting date is also critical in maintaining corn silage yield, especially this year, when growers in Northern states were still planting in June and July.
Corn planted in Wisconsin trials in late April averaged 2.2 tons/acre more silage dry matter than corn planted in mid-June. Lauer found that April 24 was the planting date that produced the maximum yield in Arlington, WI. When the agronomist factors in the average 110-lb milk/ton difference in quality of corn silage planted in April compared to that planted in June, he calculates that early planted silage produces roughly 7,800 lbs of milk/acre more.
Late-planted fields harvested before plants are fully mature can cost a producer about 4.4 tons/acre of corn silage, or about 12,000 lbs of milk/acre. “There’s nothing they can do about it this year because of the late planting dates. All we can hope for is a delayed killing frost.”
Plant density is an interesting factor in his research. A minimum seeding rate of 34,000-38,000 plants per acre is required to reach maximum yields, depending on the region. The yield of fields planted at rates higher than 38,000 plants/acre continues to increase, but milk/acre begins to plateau and eventually drops due to a decrease in milk/ton. “It’s a little odd compared to other factors, in that a trade-off exists for this input.”
Good agronomic management, including soil testing and fertilizing as needed and monitoring pest economic thresholds, can pay off as well. Pest thresholds are lower for silage hybrids than for grain hybrids, because more value can be added to milk than with grain. But that changes as grain prices fluctuate, Lauer cautions.
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