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The season is achanging

By Staff | Aug 28, 2015

There is now a chill in the air that sure makes it feel like fall is not too far away. Now if that doesn’t send a shudder down your spine nothing else will.

We all enjoy fall, with its pleasant days and brilliant colors, it’s what comes after that we don’t look forward to.

In previous years much of the Midwest went into the fall thinking that if we could just get a good rain, the crops would be able to add bushels.

Then those late rains never came in time. This year is different in that much of the state has received more than 6 inches of rain with all of it soaking in. In some ways we are prepping for the 2016 crop at this point.

Going into the season with a full profile almost guarantees a trendline crop.

Yield potential

The Pro Farmer Crop Tour was conducted last week. There are groups of field scouts that cover the eastern states while the other half heads west.

They stop at fields at predetermined distances, then enter the fields and make their corn and bean yield estimates.

The latter is done via pod counts. What they found were state-by-state estimates which may make waves on the grain markets. They found fields that looked worse than the USDA has guestimated in both halves of the country.

That is qualified by acknowledging that the eastern states plus Missouri and Kansas ratings have been very low while the western states plus Wisconsin have been much higher in ratings.

The first clue to that might be what a marketing person in Illinois has been watching for a few weeks now. He has noticed that the vegetation index for nearly all the states has been lower than in 2014.

Those normalized difference vegetation index ratings typically don’t lie and usually end up being reflected in the final yields.

Plant health

Over a four-day period last week it was apparent that something bad was happening to many corn fields.

In those fields the plants went from very green to having a noticeable percentage of the leaves turn either yellow or brown.

This all happened while there was no shortage of water to the plant. So how many growers were scratching their head asking what was going on, and thinking of how many bushels might that cost them?

It appeared that fields that ran short of nitrogen showed great occurrence of that phenomena. How much will this continue over the next few weeks?

Will it be such that local seed plots will be cut short when the varieties are embarrassing to show? Time will tell.

Will it affect final yields as the plants will lose their ability to fill the kernels as deeply as they should have?

In some cases these fields received several applications of fungicides to maintain plant health.

In cases it has been something outside of a disease causing pathogen like a fungus or bacteria that is causing the change in plant appearance.

What is also apparent is how different microclimates are making a big difference as far as how healthy one hybrid is along Iowa Highway 3 versus U.S. Highway 30.

The first area was drier through mid August than the latter. In grape and veggie country they will have sensors and programs set to alert growers to the need to apply their fungicides after a set number of dew hours based on humidity, temps and dew points.

While we don’t have such sensors in place here, the diseases act by the same environmental rules.

The important question is what percent of the grain fill will have been completed before the effective healthy leaf area index drops below what is needed to complete grain fill plus maintain plant health?

Now that we have a name to put on those caramel-colored lesions that have been showing up for seven years we can build on our knowledge of the disease and potential ways to manage it.

So far the fields that have received the BioImpruv look very good. I have one jug of the improved version to place as of Sunday at 8 p.m. If the results look good and other trials verify its systemic activity it offers the potential to apply early and manage/control late-season disease problems.

Soybean potential

On the Pro Farmer Crop Tour the important observation was the large number of small pods and continued flowering that offered the potential for another 25 to 40 pods per plant that could still fill with seeds if the weather is conducive to filling them. We have the moisture available.

The question will be available nutrition and adequate sunshine and heat. If one has to read their crystal ball it appears the hint of fall in the air is causing the earlier planted fields to show the first signs of yellowing already.

Optimum nodulation and sunny, warm weather will be vital for the potential to be realized.

Ear size

Many corn growers when they are scouting their fields are seeing that their kernels row numbers seem to be lower than normal. What should be 16-18-20 is more likely in the 14-16 range.

What might have happened?

The kernel count is decided during the V4 growth stage and having the cellular phosphorus content at .42 or higher was determined in Purdue research to be important to getting the higher kernel diameter. With conditions being wet and cool in May, plant uptake of P may have been reduced via low uptake due to low evapotranspiration or high dilution within the root zone.

Planter-applied fertilizer or early foliars can be helpful in tweaking this level up.

The other factor can be low zinc levels. A well respected nutrient expert recommends having zinc test levels in the 3 to 5 parts per million range rather than the old 1 ppm standard.

Ag shows

The 3-I granddaddy Farm Progress Show is scheduled for Illinois next week. It is being held a week later than normal, likely because not enough corn was ready for demo harvest last year. The cool spring and slow GDU accumulation left the early relative maturity corn still over 35 percent.

Insects

And now, roughly six weeks late we are seeing the corn rootworm beetles appearing.

They should be emerging closer to July 5 along U.S. Highway 20. It sure suggests that through the continued use of granular insecticides and traits we have been selecting for the late-hatching variants.

Several years ago there were efforts to label several liquid insecticides for a late-season application using the Y-drops to having a freshly applied product closer to the time of egg hatch.

The research dollars and corporate support got pulled away for other uses so the idea never got promoted. Maybe it’s time to re-examine this practice in the heavy rootworm areas.

Luckily the heavy pressure of a few years ago has been reduced by natural factors.

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

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