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Crop watch

By Staff | Sep 26, 2019

My, how our weather fortunes have changed in the past ten days. After going since late July without a substantial rain over much of the upper Midwest, we were blessed with enough moisture to close the cracks in the ground and replenish some of the subsoil moisture that was sucked out by the thirsty crops. Any of the corn or bean plants and fields that remained green should benefit with deeper kernels and filled pods.

Several noted meteorologists who recognize how both local and global events are shaped by the weather, and that there are norms and outliers, commented on how Tropical Storm Imelda increased in intensity by about 500 times when actual energy levels in the atmosphere were at normal levels. What is that part of the country best known for? Oil refining and refineries. The lifeblood of most advanced economies. When you get 30-plus inches of moisture versus the original prediction was for 4 to 6 inches, things refinery activities grind to a halt, which was during the exact week of the Saudi drone attacks.

Fall arrived this past Monday. It is when the daylight and night time hours are equal on both sides of the globe. From now until Dec 21 the daylight hours will decrease until the earth tips in the opposite direction and we make the climb back to June 21st with maximum daylength. In northern countries like Finland a high percentage of the people use blue light boxes in their houses to avoid the blues that come with reduced sunlight exposure. The best way to combat them is to spend time in a greenhouse or a tropic plant where sunlight levels are higher.

The crops in the field

In many ways this is not a normal year. A high percentage of the corn crop east of the Mississippi is still a long ways away from being mature. In Purdue’s ICM newsletter they included graphs from other delayed planting years in a comparison to 2019. The closest year they could compare to was 2009, when only 70 percent of the crops reached maturity by Oct 12th and 86 percent did not reach it until Oct 26th.

Most of the late planted corn I have been in lately benefitted greatly by the warm temps of the past two weeks. 85 degrees and sunny with a south breeze pushed the crops along, increasing the chance of reaching maturity. There are still fields where the success rate of beating the frost is still in question. Weather maps this morning showed temps in the 30s in the four corner area of South Dakota, Nebraska, Wyoming and Colorado. If the building trough stays in place the cold temps could be ushered into the upper Midwest in another week or so.

The quality and quantity of the corn crop will vary a lot, with controllables and uncontrollables creating the variance. In the second category, moisture and temperatures are the main factors. Being too wet early or too dry midseason cost bushels. The controllables are what growers can concentrate on as they aim for 2020 and beyond.

We held a tour of the corn at the Guthrie Center research farm on Sept 16th. Like on most farms this year there are three different corn crops present, with one planted in mid May, one late May and one in mid June. All are further along and have larger ears than expected. While the P and K levels are low and the ground has low CSR ratings, sufficient nutrient amounts are applied in furrow at planting, stabilized with polymers. The Take Off elicitor compound to boost plant uptake, BioEmpruv to minimize the New Goss’s Wilt, stabilized micronutrients and a fungicide were applied. All the different planting date areas were dark green and the plants had huge ears. 20 – 22 X 46 – 52 long with kernels to and over the tip of the ear being the norm. The yield potential now and expected to be added to for another 10 to 14 days is still 300+.

Nebraska and Indiana

I was out in Nebraska a few days last week to see a few growers and their fields. They had enough rain through the season that most ran their pivots around two or three times. We saw dryland corn near Grand Island that will be yielding 210 to 220 Bu/A. That minimized irrigation expense even though they will still incur the fixed costs. In most areas their corn crop was greener than our fields are. It was rare to see the fields brown with dropped ears as is the case in central Iowa.

As an aside Bob Nielson, well known agronomist from Purdue University, commented on the ears that dropped earlier due to drought or poor plant health. His commented that it signaled a reduced flow of photosynthates to the ear and kernels, reducing their weight and completeness of grain fill. In the fields I have checked on in this state a high percentage of the fields that are 80 to 90 percent brown the kernels have not black layered yet.

In north central Nebraska, most of South Dakota, northwest Iowa and all of Minnesota need more time and more GDUs are needed to help the crop reach maturity. Planting that late was a gamble more than planting the crops in April or May is a gamble.


This Sept. moisture will benefit the beans still showing much green tissue. Harvest typically begins three weeks after the first yellowing appears. The yields I have heard so far were those out in Nebraska that were in the high 70s. Illinois reports tell of beans yield ranging from the mid 40s to high 70s.

The wet weather and high humidities of the last month created the ideal environment for white mold to appear. At first it appeared in scattered plants, then as spots in the field where the humidity levels stayed higher. With the sclerotia remaining viable for 7+ years all heavily managed, full canopy beans have been susceptible in cool soil years.

Corn diseases

The learning curve on Tar Spot still exists. It is now known that 60 to 70 F along with humidity levels at 75 percent and higher for 30 days are conducive to the fungus. The current map of where the Tar spot has been detected includes about one third of Iowa, from Allamakee in the northeast down to Louisa in the southeast and west to Story and Boone Counties. In most cases it would have been a late occurrence where most growers would have decided against making a late fungicide trip.

The only product mixes deemed effective by Damon Smith at the University of Wisc were those which included a carboximide plus the new Lucento.

In all of my 2018 scouting I found only one infected plant. When specialists looked at the preserved leaf tissue the small lesions looked exactly like someone sprayed an aerosol can of tar on the leaf. Keep an eye out for this disease and check out the U of Wisc ICM newsletter.

A MicroBiome conference

There was a high level conference (the Bard Conference) at a small college out in NY State last week involving a group of top scholars from the human immune sciences, microbiome science, DVMs, the plant pathology world, the human medical community, and farmers as invited speakers. This college is the epicenter of the East Coast think tanks and is now the place to discuss the topic of how the food production system interacts with human health. An Iowan and several people well known in Iowa were there as speakers and experts. We will get a chance to visit with a few of the attendees to learn which topics were discussed and if any policy decisions will result from it. The increasing incidence of chronic illnesses due to mineral shortages or presence of AIs residue in diets was likely the focal point.

Quick Question: Which fields of yours need to be soil sampled this fall? And how are you planning to manage your corn residue so it becomes a valuable resource?

Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143 or www.CentralIowaAg.com.

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