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CROP WATCH

By Staff | Jul 22, 2011

The summer of 2011 continues and everyone who gets out in the fields to check their crops is looking at the thermometer each day and wondering how much longer this intense heat will last.

While 95-plus degrees is normal for the southwest Corn Belt, it is unusual for us.

Is anyone else keeping track of all the different cropping problems around the nation and globe and wondering what the actual grain production might be in this cropping year.

It look more each day like all the grain bins might not end up full at the end of harvest.

For weeks we have been hearing of feed mills and major livestock feeders in the eastern Corn Belt paying up to 80 cents per bushel over Chicago to buy the actual grain for their feed needs.

The big wind

Because we have gotten used to at least one major storm roaring through the state each summer at just the wrong time none of us were surprised when last week’s big windstorm showed up. While the first reports showed damage from just south of Ames to Cedar Rapids as the details were released we learned it begin in southwest Nebraska on Sunday night, made its way into Northwest Iowa, then into central and east central Iowa and continued on a path through the Chicago to Detroit, into Canada clear to the Atlantic.

One Iowa grower said that he saw downed corn through Indiana and Ohio.

The affected growers, of which there are many, are now wondering how that corn that blew down or snapped might produce.

Based on what I have seen in similar big winds, it is too early to tell. So much depends on weather conditions through the rest of the season. In both 1987 and 2004 we had big winds along U.S. Highway 30. The 1987 wind was followed by hot, sultry weather and calm conditions.

The collapsed stalks had little wind moving through the canopy and the plants got extremely hot and stressed.

Ears placed close to the ground did not pollinate on the bottom side. Plot and field weighings that fall told of yield decreases in the 50 to 70 percent range.

Now in 2004 near Marshalltown and west a big swath of corn was blown down just after pollination. It was a very cool year with lots of small showers and gentle breezes most of the days. The corn plants were never stressed. Final yields didn’t seem to be affected much as many fields ended up yielding over 200 bushels per acre.

One of the worrisome aspects of this storm is in fields where roots were torn loose. In a wet year the plants should be able to get by on having only half of the original roots. In a dry year it will need most if not all of the roots for moisture uptake.

Plants that stand up mostly upright should fare better, but for the plants to complete the task of growing new roots, energy had to be devoted away from the ear formation process.

In one to two weeks we should be able to go into the affected fields, pull the husks down, and see how many of the kernels on each ear pollinated.

Silks hanging straight down are not great targets for the heavy pollen grains to land on.

So in another week or two there will likely be lots of growers who normally would have considered spraying with fungicides to protect yield will be saying the heck with any additional expenses and letting their insurance company write the checks.

It is human nature to try to save things, but isn’t that why they bought the policies.

Soybean status

From what I have seen the soybean crop suffered no damage from the storm. They got whipped around but were short enough that the wind blew over them.

Normally on July 20 it is time to make the last pass through the R3 beans to apply any fungicides, insecticides and possibly foliar fertilizers.

The lowest pods should be about 3/4-inch long and the plants have about two weeks of flowering left. This year most of the beans are still in the R1 to early R2 stage.

It is interesting to read all the articles from the experts who profess that foliar applications of fertilizer do not raise yields. It’s a good thing that guys like Ray Rawson don’t pay attention.

Experience and lots of trial and error by such growers has helped to blaze some paths that others can follow. One good rule to recognize is that such applications need to be made using the right recipe and timed to when the plants are most receptive, rather than when it is convenient to spray.

If one thinks about how a researcher who adheres to banker hours will time their applications it becomes easy to see why failure is their rule. Rain at the right time is also very important. A person can set the stage for tremendous results, but rain in August is still needed to fill those pods.

New ideas

I did get the chance to enter a greenhouse complex where new products were tested on several crops to see if their use could increase plant growth and grain production.

It was a complex belonging to an international supplier of plants grown to supply food for the country and very well recognized for their testing ability.

The hydroponic tests were recently completed on the different crops and the best of them showed the soybean yields had been increased 233 percent above the check yields. Now the trick will be to make the work and products applicable to dryland farming. Stay tuned.

The heat

There are many farmers and outside people who are asking what the heat is or will be doing to the corn and bean crops. It has been about seven years since we have had such a burst of heat and the plants will give clues as to how they are faring.

Temps in the high 90s are well tolerated by the corn plants as long as they have adequate moisture and have enough deep moisture reserves to meet transpiration needs.

It is when reserves run short and the plants begin to show signs of wilting that they can begin to lose yields.

There have been different figures discussed over the years, but it is possible that a day of extreme leaf rolling can result in losing 5 percent to 6 percent of the potential yield. If they can recover some at night that is a great help in retaining the young kernels.

A few farmers have purchased the infrared automotive temperature guns to take the plant temperature.

By comparing the plants surface temp with the ambient air temperature they can quantify the lack of cooling ability.

Sensitive research potentiometers can measure stress and express those readings in terms of negative bars of pressure.

There could soon be evidence of which fields have deep root systems and which ones are struggling. At this point most growers are seeing the benefits of good freeze/thaw action over winter that opened the soils up once more.

In greenhouse trials where several different biological have been tested several different fungi (such as the trichoderma in U.S. and Israeli trials) and bacteria have proven to be great aids in helping different crops tolerate stress.

They seem to allow the plants to maintain a higher turgor pressure during times of low moisture availability.

So far most fields are still looking good during midday. Having a full profile just a few weeks ago on soils with a high moisture holding capacity is often why this part of the world has gained such a reputation for being good corn growing country.

As to the heat affecting disease occurrence, such conditions typically reduce the number of hours where moisture films exist on the plants, reducing the disease threat.

Check each crop near sunset and early in the morning to see if heavy dews are still forming. One doesn’t need rain to keep the interior part of the canopy moist for 12-plus hours each day.

If the leaves are staying dry, then try to determine if that will be the case over the next several weeks during grain fill.

Bug watches

To this date aphids are appearing in northern and part of central Iowa. The numbers remain low, plus we know they don’t reproduce well in 90-plus temperatures.

European corn borer larvae were still tunneling in the whorled leaves. They are present about two weeks later than normal in non-Bt hybrids and should be watched to see if ETs are reached. Now is when the first moths of the second brood should be starting to fly.

The last insect of consequence might be the stinkbugs in beans that could cause feeding problems once the pods begin to form.

In Illinois the CRW populations seem to be making a rebound.

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

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