A farmer has hundreds of corn hybrids from which to choose, and those are just the ones within the relative maturity (RM) range appropriate for where he or she farms. An acceptable range in maturity is usually about 10 days of RM – for instance, a range of 100 to 110 days RM.
In this case, you’d expect a 100-RM hybrid that’s planted timely to mature every year, while a 110-RM hybrid would mature almost every year but would provide a bit more yield potential during a year with more heat units than normal.
We’re starting with the impact of weather because this has more influence than any other single factor on the yield and quality of corn silage. The other “biggie” is harvest timing, but when the crop is ready for harvest is also related to environmental conditions, since the weather influences when you can plant and crop development.
Getting started
I think you should buy corn hybrids for silage only from seed companies that evaluate their hybrids for silage use. This doesn’t necessarily mean they sell silage-only corn hybrids, but they should have silage yield and quality data, including fiber digestibility. In some seed company catalogs, corn silage is mentioned only in passing – or not at all.
This isn’t surprising, since typically only 6 to 7 percent of U.S. corn acreage is harvested for silage, but how much does a grain-oriented seed company know about the performance of their hybrids when harvested for whole-plant silage?
It might actually have one or more hybrids well suited for silage, but if the company isn’t willing to evaluate its hybrids for silage, including both yield and quality, you should look elsewhere for your seed.
Silage-only hybrids
Some silage-only hybrids are higher in neutral detergent fiber digestibility (NDFd) than just about any dual-purpose hybrid (intended for harvest as silage or grain), but many dual-purpose hybrids are higher in NDFd than some silage-only hybrids. Got that?
And just because a silage-only hybrid is higher in NDFd doesn’t guarantee it’s a better hybrid than a dual-purpose one. There’s also yield, starch content, disease and drought resistance, standability, etc. There’s simply no one hybrid type that fits all situations.
The two major types of silage-only hybrids are BMR and leafy gene. Almost all BMR seed corn is sold by two large multinational companies, while leafy hybrids are sold by a number of companies.
University trials comparing BMR hybrids are few and far between, but both companies have BMR hybrids reliably higher in NDFd than conventional hybrids but (usually) slightly lower in yield.
There are many situations where a farmer would be willing to sacrifice some yield for increased NDFd, but this depends on the herd’s milk production level, rate of corn silage feeding, willingness to pay a premium price for BMR seed, and how upset they’d be if their BMR corn didn’t look as pretty as their neighbor’s conventional corn.
BMR corn may not be impressive-looking in the field, but BMR silage puts milk in the tank and, as mother used to say, “Pretty is as pretty does.”
Leafy gene hybrids are almost the opposite of BMR corn. “Leafies” have up to 50 percent more leaves above the ear than do conventional hybrids and, because of this, they look great in the field. Most leafy hybrids are priced similar to conventional hybrids.
In spite of their good looks, university trials have found leafy hybrids don’t have a consistent advantage in yield or forage quality. Some leafy hybrids are top-notch performers, combining high yield and good forage quality – while others are just so-so. Therefore, farmers should buy leafy hybrids based on proven performance, not just because they have the leafy gene.
Back in the 1990s through the “aughts” when I managed Miner Institute’s crop operation (Chazy, New York), we planted a fair amount of leafy corn, but that was because a couple of leafies were at or near the top of Cornell University’s silage hybrid trials.
Traits
Farmers now have the choice of no fewer than six genetic traits: tolerance to the herbicides glyphosate (Roundup), glufosinate (Liberty) and 2,4-D plus drought tolerance and resistance to corn rootworms and European corn borers. Several traits can be “stacked” in a hybrid, and it’s important to choose the traits needed for each field situation. Don’t pay for traits you don’t need.
For instance, if you won’t apply glyphosate to your corn, then you don’t need hybrids with the Roundup Ready trait. And there’s no need for a rootworm resistance trait in first-year corn coming out of forage production. It’s now more important than ever for farmers to keep excellent records so they know what hybrid with which traits is planted where.
Many of us have heard of the farmer who had his corn sprayed with glyphosate thinking it was a Roundup Ready hybrid. Then all the corn started to die … oops.
Disease resistance isn’t a genetically modified trait, but it’s something you should be able to find listed with hybrid descriptions in the seed catalog. If not, ask your seed dealer to get this information, since it may be available even if it’s not in the catalog.
Most seed companies rate their hybrids for resistance to northern corn leaf blight and gray leaf spot, but some seed companies include hybrid ratings for several other corn diseases. When a disease such as northern corn leaf blight is present in a field, the difference between a hybrid with a high rating for northern corn leaf blight resistance versus one with a low rating can be tremendous – literally a matter of life and death for the corn plant.
And there usually isn’t any price premium for a hybrid with high resistance to a particular disease.
Finally …
There’s not nearly as much yield and quality data available from land-grant university silage trials as there was even five years ago. Part of this is from cutbacks at the universities, but some seed companies have stopped entering hybrids in university trials, so farmers have to look for other sources of information.
These may include crop management association trials and recommendations, seed company trials, and the advice and experience of seed dealers and your neighbors.
How a particular hybrid does in a university trial three states away is interesting; how it does in your county or on your farm in a side-by-side trial with other hybrids is much more useful.
Everett D. Thomas
- Oak Point Agronomics Ltd.
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