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CROP WATCH

By Staff | Aug 4, 2017

As we and our crops enter the month of August, when the majority of the grain fill is supposed to occur, and in the southwest 75 percent of the state, most of the enthusiasm about the last part of the growing season and the upcoming harvest is gone. Sixty days with very little rain was the cause and all we can do is hope that a major front will deliver the needed showers into the dry areas. But for most the damage is done and the top end or much more of the yield will not materialize. This is a-typical in that most of our droughts are supposed to come in from the south and east. This one came in from the west, northwest and southwest. Yet states to our east received rain that skipped over western Iowa that rematerialized once it reached the eastern third of the state. As to individualized areas the fields along and east of Hwy 65 have fared much better than to the west.

As to news from the Streit Ranch it was a busy week where we had to attend a first cousin’s wake up in Osage, a college friends son’s wedding in Manchester and a class reunion in Stacyville. I did a quick count and tallied 11 close relatives that have been affected by cancer with about one third surviving. More people are recognizing this trend and wondering what the causes are. Is it coming from the air, food, water or environment?

The status of the crops

While we have been watching the corn curl up most days and many of the plants west of Hwy 169 only reaching fence post high it seems no one in Chicago is hearing the real story. To the market watchers the cropping situation is all roses. Last week when the impending 2 to 3 inch rain fizzled to a .2-inch dust settler the word in Chicago was that the western half of Iowa had received one to two inches and everything was dandy. If only that was the case.

There are a few scattered pockets like around Carroll and Marshalltown where the conditions are better and more similar to the northeast quarter of the state where conditions have been wet enough that some fields operations were delayed. The area that received the 10 to 12 inch rain was very near the area that got the 18 inches close to the same time as last year. Whoever is in charge just needs to spread the rain out a bit more.

So how is the corn crop fairing across the Midwest? Locally, there is corn that tasseled between the 15th and 20th of July and some due to tassel this week. In places the ear length looks good but the average rows around seems to be down two to four rows. The rows long varied dramatically and the final tally will change. There were pictures of ears from different states where the ears were a nice 18 by 42-46 kernels, but the dry and very hot conditions had caused about a 45 percent rate of kernel abortion already. The loss of tip kernels typically occurs thru the blister stage and this year the problem could be huge. Still to be seen yet is the depth of kernels. If we don’t get much more rain in the near future expect shallow kernels. One thing that became more apparent last weekend was the change in color of many cornfields across the state. They switched from a decent green color to various shades of yellow. Several of us were speculating on the cause. The number one idea was the that in many fields the nitrogen had been applied and was being held in the top foot of the profile. Now that the top 12 inches of soil was bone dry, it was no longer releasing the nitrogen to the roots. Idea number two, was that in recent years the corn has died completely around Aug 18- 24, but the first color change associated with this development became noticeable to the most observant students around the 10 to 15th of July. This could have been the case again and it was much more noticeable in northeast Iowa this past weekend. The number three proposed idea was that the plant in many fields have had no moisture recharge and have been short of moisture typically used to cool the leaves by evapo-transpiration. Unable to cool off the leaves are scaling and having the proteins denatured. Take your pick about which description fits.

But in many areas the corn can still appear to be tolerating the drought fairly well. The deeper the roots, the higher the organic matter, the more adequate the mineral balance in the plant and the better the water infiltration into the soil, the better the condition of the corn crop.

Several different parties have advanced the theory that planting very high corn populations is the way to super high yields. It may work sometime, but my bet is to work in developing a deeper and healthier root system that is able to grow into a higher organic matter soil that is more biologically active.

The soybean crop

If you compare the stage and condition of the bean crop to other years the 2017 plants are still running about 3 to 2.5 weeks behind normal with much shorter plants. There are many fields where 30 inchrowed beans are not closed and places where 15 inch beans are just barely doing so. The podded node count is 9 to 12 on average and not the 17 to 19 needed for 65 Bu/A yields. While the R3 growth stage where the lowest pods should be nearly an inch long many plants have barely formed pods so far. We know that beans have a high recovery ability, but this season they will have to recover a lot to even reach low trend line yields.

In retrospect a high percentage of the late planted beans could have benefitted from a strong foliar program beginning about V3. Mixes containing P, sugar and minerals could have boosted growth as well as branch numbers to help compensate for the later planting dates.

The number of fields and the extent of the severity of the IDC were very noticeable earlier this summer. While the name indicates it is solely an iron problem the mineral levels and plant available levels of Mn and Mg have to be discussed. More on this later.

Field observations

A crop consultant from central Nebraska was telling me last week about his battle to control Palmer amaranth in fields he was consulting on. The strain they have near Kearney has proven to be resistant to Banvel, ALS, SUs, post HPPDs, PPOs and Rup. They are pulling what hair they have left out trying to mange it and are settling on using 2,4-D, as the bad fields were planted to corn. I don’t think any of us are looking forward to this battle.

While on this topic it might be time to mention the Dicamba drift problem. More news stories came out last week. First were the stories about the bean growers from Arkansas who had intended to spray one of the approved products on their bean fields to control broadleaves but were not able to spray with the intended products. The ban prevented them from doing so and they expected more cost and less yield as a result. So they were initiating a class action suit against the seed and herbicide suppliers.

The other happenings were the availability of the 100 page court transcript which detailed the story of two very good state extension weed specialists and knowledgeable experts who had request samples of the major Dicamba formulations for testing them to see if their vapor pressures were lower than the products from years ago. They were prevented from doing so. Their eventual conclusions were that their findings would have been that high vapor pressures and the regular occurrence of air inversions were bound to cause problems to the offending chemicals. If court cases are decided on strong evidence and proof of ignoring warning opinions, a few companies will be forking over some major cash.

This still leaves questions about how to control tougher weeds that our management strategies have selectively bred. More than one person is thinking that some combination of cover cropping and cultivation might be in their future. Will it be optically control cultivators as they use in Europe.

Plant diseases

The last three weeks in July have now become the season of fungicide applications on many acres in the Midwest. What I have learned over the past five years, while often suggesting the use of fungicides, is that growers need to be expanding their thinking so they are asking why their crops are now so susceptible to so many different diseases. Have the diseases gotten more virulent or the plants more susceptible for another reason. The reason appears to be the latter. Thus most fungicide applications should be preceded by tissue analyses. A fungicide application can wipe out the fungal population but does not remediate the underling mineral deficiency.

I did begin to see the 4 to 5-inch long brown slimy lesions from 6-inches to 2.5 feet above the soil line that I have been seeing in recent seasons. That never ends well and will need to be addressed shortly.

Next week I will cover some of the findings of the early fungicide trials conducted in Brazil, Argentina and Paraguay that went way beyond those in the U.S. that provided answers to their huge disease problems.

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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