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Crop watch

By Staff | Jun 28, 2019

Now that summer has officially arrived we can begin by summarizing how the spring went and what we can expect to happen during the first part of the season.

After the delayed start to the 2018 planting season where many of the crops got planted weeks late we were all hoping for an early, consistently normal nice weather period where we could get 80 percent of the corn crop in by May 1st. Once that was complete we could make quick work of getting the bean seed in the ground. No rush, no hassle, just as planned. Instead both the corn and bean planting season drug on much later than in any other season, to the point that a record number of prevent planting acres were registered.

Now our job is to get as much heat as tolerable by the small corn and bean plants so they can complete their growth stages before the summer cool down and fall freeze dates. Having these many cool days is not desirable. There are lots of tasks such as getting any final fertilizer passes done and making the needed herbicide application trips on the soybeans on time that will be required with the hoped for cooperation by Mother Nature.

Unplanted acres

As to the status of the crops across the Midwest, the planting dwindled to a slow stop on about the 15th of June. I was up in Northwest Iowa and Southeast South Dakota early in the week and over the weekend had to attend a nephew’s college graduation out near Chicago.

What I saw in South Dakota west of South Falls was somewhat shocking as there were a lot more Preventive Planted acres than expected right across the border. With their tight clay soils, lack of decent tile and outlet drainage, smaller feed needs, plus earlier frost dates more farmers faced reality and filed for Prevent Plant.

In places at least 80 percent of the fields were and will stay that way until a cover or forage crops is planted. In comparison only the Iowa fields with very poor drainage ended up in that category. Until we see a NASS survey that posts this high figure for that area its accuracy has to be challenged.

What was apparent in Illinois was that while our field conditions improved May 15th – 20th, much of their state got hit hard by heavy rains coming through Missouri, missing most of Iowa. This problem persisted until June 6th. Just as in Iowa, farmers refused to admit defeat and were determined to fix the problem, continuing to plant corn until June 9 or 10. Bean planting continued for another two weeks.

The view to Chicago and back on June 21-23 was that they have few fields beyond V4 to V6 in the northern part of the state. Many are only at V1 to V2 with the cooler weather slowing growth and development. There were also many Preventive Plant fields on flat ground and even rolling fields where the valleys and ponds never dried out.

The soybeans in most areas are lagging much behind normal, as soybean plants require three days to recover from sub 50 degree temperatures. The tallest ones were at the V2 to V3 stage with most at the Vu to V1 growth stages. Since they must reach V5 in order to flower this process has been postponed for two weeks this season.

Tasks at hand

Tissue or sap analyses are the best ways to determine if the minerals in your soil are getting into the plants. The optimum time to pull tissue samples is at V5 as most labs offer quick turn-around so as to facilitate taking action.

The warmer temps should facilitate both soybean plant and weed growth. Thus assessing weed populations and making any post-emerge applications before the weeds reach the 4-inch height is important. I expect the Spray Tech mixtures to be used on more acres as their phosphite, mineral and amino acid mixtures used as surfactants offer both weed and disease control benefits. Spray Tech and Redox Chem are the two companies leading the pack on new mineral technologies that improve weed control, plant health, produce quality and minerally enhanced final products.


A number of seasoned agronomists and grain handling staffs at the major grain terminals are doing their calculating now to project several things: the race to get the corn crop to maturity; the harvest moisture of the grain; any steps to coax higher yields on all the late planted bean fields; and how to keep these late plants jeorpardizing the timing of the 2020 crops.

Knee high corn by July 4th used to be the standard in order to beat the frost. In the last 10 to 15 years we have seen many early planted fields tasselling near that date. In 2019 many growers are hoping their late planted corn fields reach that mark by July 4th. The slow rate of GDU accumulation and the rapid cool off during most days in June has slowed plant development. While in 2018 the record hot temps in June created the fastest growing corn crops most of us have ever seen, this year we have seen the opposite.

A colleague from the Iowa City area worked through the calculations and came to the same conclusions of other agronomists. For example a V4 corn variety on June 20th that typically forms a total of 18 leaves will require another 7 weeks if the temperatures stay cool to reach the VT tasselling stage by Aug 8th. The tasselling through black layer stage typically requires 60 days, so this field will black layer near Oct 8th.

The grain moisture will be around 33 to 34 percent. Corn plants that have not yet reached V4 will be later to reach all of those marks. Several different events could help the later planted corn, warmer than normal temps from now on, varieties that put on fewer than 18 leaves, more clear days rather than diffused sunlight or a later than normal frost. If a person can increase RUE or radiation use efficiency it would also help treated fields. Increasing the sugar content of the leaves will help to frost proof them. Having a high level of biological activity in the soil should also speed plant development.

An idea that a mineral researcher has been experimenting with for a few years has developed a mineral, sugar and biological mix that he applies in furrow at planting time. He has measured a 15 degree increase in soil temp as a result. He has also seen foliar applied silica increase leaf thickness, improve energy capture, and lowered the freeze tolerance of the leaves. If the 58 year Maudner minimum continues to become more apparent we may have to resort to different tricks in order to raise coarse feed grains.

Additional nitrogen

The first response by lots of corn growers is to apply more N when a field takes on a yellowing appearance. That may be the proper choice, but a more judicious path would be to take a tissue test to determine if a shortage of Moly or Zn/Bo/Cu may be present. Remember than Moly is short in 95 percent of the tissue samples sent to the major testing labs.

Because the weather trend in recent years has been for wetter and cooler springs with extended period of saturated soil, more growers will have to take proactive steps to stabilize their applied N. This can be done with a number of minerals, sugar containing, humates or soil microbe affecting stabilizers. Later sidedressing also makes sense since most of the N utilized by the plants is needed after the V6 growth stages.

I should mention that we expect to be testing a nitrogen fixing Glucono-acetobacter that can be applied to allow each of its cells to extract N from the air. About six year worth of work in the U.S. and Europe has been conducted so far. We hope to have it on display in a few plots this fall.

Soybean plant stimulation

The bean plants have many of the same challenges as the corn plants, but they need to be managed differently since they are a C4 hormonally driven plant. When they reach V3 to V4 a foliar application of minerals/microbe food/respiration promoter will spur rapid growth and plant development. Applying a low salt liquid P will help spur plant growth as well. If possible any means to apply a cytokine hormone will increase branch number. After that we like to see a 17 product mix called Seed Set applied to shorten the internodes, strengthen the branches, and do a number of other things. We have seen such steps improve mid June planted bean yields from low to mid 20s by 30 Bu/A. Improved and high bean yields don’t happen by accident. They are usually carefully planned and managed for.

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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