Renewable Farming

How a few corn growers are overcoming “early die-down” — and adding bushels to yield

Dr. Michael McNeill of Algona, IA is one of the most seasoned Midwest crop consultants we know. His firm is Ag Advisory, LTD, serving farmers for 22 years. For the past several years, he has expressed concerns about early die-down of corn. At field days we’ve heard Dr. McNeill asks: “What’s different — what’s causing this to happen? Corn used to be one of our healthiest crops.”

Sept. 25, 2017 — An upcoming field day hosted by Dave Schwartz Monday, Oct. 2 near Guthrie Center will show farmers a second year of “keeping corn green” with a wide-ranging array of techniques, starting with healthy soil and supplementing with foliar nutrients and biologically based products which keep corn healthier longer. Download the PDF to see details.  

When late rains arrived across parts of Iowa this August, we had hoped that corn would have a better chance to keep on deepening kernels and adding test weight. But by early September, most cornfields switched from green to amber — almost over a weekend. “Die-down” hit again. Drought was a significant factor, but not every field in drought areas browned off early. In the dry season of 2012, our “biological” fields of non-GMO corn remained green into late summer. Nearby traited and conventionally fertilized fields had fired severely (see comparison photos below).

So why are a few fields of corn still green, here at the end of September? Genetics and fertility and chemicals must be part of the web of factors involved. The 2017 season wasn’t an especially tough year for Goss’s wilt, or waves of any well-known fungal disease. Yet, nutrition starvation and vascular plugging from some source lurked as visible symptoms.

In September, consultant Bob Streit made these observations in his weekly summaries posted on his firm’s website:

Crop consultant Bob Streit’s observations on the Corn Crop in the Midwest
Sept: 15: “The condition of the corn in the state rates from completely dead to still green and filling. Over the first weekend in September the appearance of many fields in central Iowa changed dramatically in that many turned brown on a high % of the leaves and came close to complete senescence. This occurred before the normal timing of maturity and before the normal grain fill had completed. The kernels on those plants shrunk down and have now formed a black layer. Yields declined from what should have been and there is a high chance of poor stalk quality.
“Some of those fields that died early were in the extreme drought areas, while others were close to fields that have stayed green and factors other than lack of moisture were involved. One management step that appears to have helped was the application of foliar ammonia based nitrogen which helped to keep the plants from cannibalizing the upper leaves. A larger factor would have been the plugging of the vascular system of the plant which blocked the flow of water and nutrients to the leaves and developing ears.

Sept: 22: “When a person has driven an hour down the road in the past few weeks it should have been apparent that the plant health again was some level of poor to terrible in quite a few fields, especially south of Hwy 3. Some of it was due to dry weather, but much was due to disease issues resulting from poor mineral nutrition. The application of fungicides helped in some cases, but didn’t solve the underlying issue of lack of the minerals needed to fuel the immune system function and attain top yields. Then after last weekend the death of a high % of the remaining somewhat green fields became even more apparent. Those two days and this past Thursday with 90+ degree temps and a dry south wind with low humidity levels was the final blow. As a result the grain from those fields will be shrunken and lighter in weight.

Sept. 24: “The trend that seems to be developing is that fields with better moisture holding capacities, better biological activity, and managed such that the plants stayed greener longer have been forming kernels that filled much longer and much deeper versus varieties and fields that died early. The point that good soil health is important is being driven home more with every field that has been harvested. Growers seem to be recognizing this axiom. I stopped to visit with Ray and Lance at Ward Labs on Monday of last week. Two years ago they were accepting maybe 12 to 15 soil samples per week for a Haney Analysis. On Monday they received over 200 samples for the same test.”

The power of soil biology and season-long nutrition — fed with foliars — is showing up. Our reports earlier this month, here and here, showed evidence that stimulating soil biological activity helps feed those nutrients to corn deep into the summer.

Here’s a photo of our test-farm corn… back in 2012, when early die-down of fields began to invade the agronomic scene. What we’re seeing this fall isn’t new. But the immature die-down phase appears to be shifting a little earlier each season.