When one of our eastern Corn Belt clients asked us that question, we quizzed a few specialists with inside knowledge of the seed corn business. The essence of their answers: Killing seed fields before seed maturity can lower test weight, cut germination and reduce seedling vigor.
Aug. 2, 2018 — Your seed rep may tell you that terminating seed corn fields by spraying the corn with salt water is done to assure that seed escapes freeze damage. A quick, uniform harvest is a logistical goal. It’s hard to accomplish where a single seed processing plant must harvest, dry, shell and inventory 10,000 acres or more in a tight time window.
But as crop consultant Bob Streit points out, killing the cornstalk before seed reaches mature black layer compromises the finishing flow of minerals and oils into the seed. Test weight may fall by a third. The percentage of smaller seed rises. Germination rate can suffer. Bob has several years’ experience in the seed breeding industry.
If cold germination drops too low, the weakened kernels are unsaleable for seed. One of our Iowa WakeUP clients who fed cattle scouted seed plants for low-germ seed and bought it — before fungicide treatment — at a discount for cattle feed.
Gilbert Hostetler, president of Prairie Hybrids at Deer Grove, IL, confirms Bob’s experiences and adds more specific reasons some seed companies kill seed corn fields a couple of weeks before black layer: Seed corn companies pay growers by weight. If test weights are lower, each 80,000-kernel unit of seed corn costs the company less.
Prairie Hybrids, which raises and markets only non-GMO and organic seed, does not terminate seed fields before full black-layer maturity. Here’s a summary of what Gilbert told us about this practice:
“Critical minerals like manganese and molybdenum flow into the seed the final two weeks before black layer. It’s no secret that some of these seed companies have gotten caught with their pants down when their seed didn’t germinate well.
“A seed is like a baby. If a mother gives a baby too much salt, it’s not a good day. Does killing seed corn with salt hurt yields from that seed? I’m convinced it does. How much it hurts is debatable.
“We hold off seed harvest until black layer, then hit it. Do we have some big seed? Yes. What we do on the big seed is to sell 40,000-seed units, not the standard 80,000. Of course we have other genetics that makes small seed too, for farmers that want it.
“If seed corn is above 80 pounds per bushel test weight, we allow a discount. Some farmers prefer that.
“One thing that helps Prairie Hybrids with our emphasis on nutrient density is that ten years ago, “biological” was a bad word for many farmers — but today it isn’t. What grandpa H. W. Hostetler promoted back then, more farmers are ready to listen to now. Even the chemical company that helps with our field days is promoting biology.
“We stress in our field days that if seed is short of traces like molybdenum, that corn can’t metabolize nitrate nitrogen and ammoniacal nitrogen into protein and amino acids. That leads to a plant sap composition which attracts aphids — and then disease follows.”
There are usually many dimensions to any “story” — so if you have additional facts, we’d appreciate seeing an e-mail from you telling of your viewpoint and experience. We’ll update with “additions and corrections.” A practice like salting seed corn fields could morph into an overblown modern legend, similar to the myth that Romans salted fields of vanquished peoples to make their land sterile. That was early fake news. A good analysis of that fable is at this link.
Here’s a flyer on the 2018 Prairie Hybrids field day Sept. 6.