Take important steps such as corn tissue sampling

by | Jun 9, 2017 | Crop Watch

June is here and we are left wondering where the first part of May went. Lots of cold days and rainy weather eliminated many of those very pleasant and first warm days that typically mark the beautiful conditions we typically experience while everyone is intent on getting their two major crops in the ground. Now by June 4th we get slammed with the first 90 degree day where we begin to wish for cooler temperatures again. Every indication so far seems to indicating that this growing season is going to be erratic for most Midwest growers during a period where we don’t need many surprises.

The tough part about the season is that the same amount of work with tillage, planting and spraying had to get done, but in a shorter amount of time any only when field conditions allowed it. Most growers would take dry conditions over a wet spring in nearly every instance.

Observations of the crop so far

My travels last week took me into Illinois on Thursday and Friday. The earlier reports told of many wet fields and corn and bean fields that were still unplanted or had plant stands that may require replanting. Earlier reports stated that up to 5 million acres would have to be replanted. What I saw was reminiscent of three or four years ago when incessant rains left many fields along Hwy 30 and much of northern Illinois with plants that were barely fence post high and very yellow by mid- August. There were areas where waterholes had formed and drowned out the emerged plants. About half to two thirds of the bean fields had been planted for the first time around June 1. Most of them had not emerged yet.

The progress of the corn plants in nearby fields was slightly better, but not by much. The height of the plants ranged from V5 or early V6 down to still not emerged. The average was late V3 to early V4 and much of it was very yellow. In a lot of cases the growers early inclination was to replant, but when the fields finally got dry enough to do the physical part of replanting the long term guidelines suggested they were likely bushel and financially ahead leaving the lighter stands. It is always tough to dismiss all of the heat units that have been accumulated by late May and start completely over. In cases the scarcity of adapted seed varieties and supply came into the decision making process.

Their progress on soybean planting has been a lot like ours in that much of it took place two to four weeks later than preferred. And any fields that did get planted in late April, like ours the plants were still only in the late unifoliate growth stage. Not enough heat or sunlight was gained in those lost 3 to 4 week to let the bean plants advance beyond the earliest stages. Their challenge is the same as ours in that later planted beans will stay shorter, have fewer branches, and form fewer podded node and total pod county unless very aggressive management steps are put into play to counter act those negatives.

From what I have heard second hand or gleaned by viewing the crop ratings from the major 10 grain producing states is that the progress of the corn and bean crops get progressively worse as one goes east and south in the corn/bean belt. It has been a while since a person could read where Indiana and Ohio had only half of their crops rated good to excellent. One comment from a very sharp grower was that after viewing the scenery in those states he thought their crops were over rated. We shall see.

Crop Progress

So how do things look in the state and nearby surrounding areas? The corn must have been forming root tissue even when it was not adding much height. Much of it is now in the V4 and early V5 growth stage, which is when it normally begins to add lots of height. The very yellow color is noticeable and is likely to become more pronounced depending on which herbicide they have or will be applying. Any that are broad spectrum chelators that tie up specific minerals for two to three weeks will cause more yellowing, based on which of those minerals are already deficient in the soil. It takes time for the roots to counteract the chelating effect and recover from the spray application.

The yellowing is more pronounced on the sidehills where the organic matter levels are lower and the reserve supply of the crucial minerals is lower. One related effect it that many of the safteners that are contained in more of the herbicide mixes don’t act as completely as they would do if the organic matter and mineral levels were higher. Remember that herbicide degradation problems can be cumulative. Thus operators that may have to view such problems will have to review which of the products they use are contained in the same action class of chemistry.

Like in Illinois some of the emerging stands in different parts of the state were not as good as planned. Some of the worst were replanted. There were also some that would have been replanted if they weather had allowed it, but in the end the late replant date squelched those reaction plans.

The soybeans have mostly emerged as expected and with the recent heat have begun to advance. Will any of them be at the V5 growth stage by June 21, which is when flowering typically begins? A lot will just barely be that far along.

The bean growers who have a concrete plan on how to force more branching on their plants is likely to benefit from such knowledge this season. Getting each plant to add two to four more branches will help compensate for fewer podded nodes.

In making estimates we have to conclude that a high percentage of the plants are scheduled to reach the tasselling stage between July 20 and early August. The ears need to reach late blister before they begin to accumulate dry matter, which would be around Aug 10. That places a lot of importance in helping the plants stay healthy and supplied with minerals through all of August and into late September.

Important Steps

Even though it would be nice to take a deep breath and relax, there are several tasks that need to be done. First would be to take to the corn fields with sample bags and cut off and bag about a dozen plants from each field, in a representative area of each, and then send them to a soils lab for a nutrient analysis. The two most popular labs are Midwest Lab in Omaha, followed by Ward Labs in Kearney, Nebraska. Request a mineral analysis and consider asking for a Moly reading as well. The last is a separate test and needs special extraction fluid. It adds cost, but that could be recovered many times over.

Each mineral fills a specific role in the plants metabolism and construction process. If that mineral is less than adequate, meaning low, very low or non-existent there will be consequences such as greater disease susceptibility, greater heat and drought stress susceptibility, or lacking in the ability to photosynthesize sugars to promote high yields.

If you sample this next week you should be able to get the results back in time to procure the better foliar fertilizer products apply them in time to remedy most of the nutrient deficiency problems. Leaving those plants deficient in minerals such as Mn, Cu, Bo and Zn much longer opens the plant up to fungal or bacterial attack. Applying and getting adsorbtion into the plant that can then help the plants resist the pathogen attack.

One thing that plant scouts have been noticing is that in many fields between 5 and 10 percent of the small plants emerged but died when the roots rotted. Seed treatments helped, with the best ones containing both minerals and biologicals.

Weed Control

The grass control from the pre-emerge herbicides looks good so far. The broadleaves in most fields will need to be addressed. Over the next ten days those will be appearing in more fields and we will see how well everyone’s residual program performed. Hopefully the preplant PPOs continue to stay effective and stay around as a viable class. Remember to treat emerged weeds early as there are very few reliable rescue products.

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