Cool, wet spring could affect yields later in the season

by | Jun 2, 2017 | Crop Watch

After another wet week, it is time to recognize the meteorologists who read their tea leaves and observed the galactic cycles to predict a cooler and wetter planting season. Kudos to them and their willingness to stick their necks out. To the brave shall belong the subscriptions and followers. Lots of Ag wives, mine included, ask why we have to watch the 10 p.m. weather. We tell them that everything we do depends in the weather. And depending what happens the rest of this season an applicable phrase might be ‘A man who has lots of food has lots of problems. A man who has no food has one problem’.

What make this season different to us is the enormity of the planting delays. The Van Trump report listed the percentages and the corn acres not planted for the 21 major corn growing states as of May 21. In the major corn growing states of Iowa, Illinois, Indiana, Ohio, Nebraska, Minnesota, Wisconsin and increasingly Kansas, North Dakota and Missouri, planting delays can have a huge impact. The figures for percentages and numbers of acres are: Iowa at 8 percent and 1.064 million; Illinios at 11percent and 1.23 million: Indiana at 24 percent and 1.34 mil; Ohio, 27 percent and .95 mil; Nebraska at 13percent and 1.24 mil: Minnesota at 6 percent and .48 mil: Michigan at 35 percent and 1.4 mil: Missouri at 7 percent and .227 million, Wisconsin at 35 percent and 1.4 mil; and .227 mil: Kansas 30 percent and 1.56 mil: North Dakota at 12percent and .648 million.

The acreage tally has not changed for this week as most of the farmers were shut down except in the more rolling fields. Planters were operating on Friday in south Marshall county and a few eastern Iowa counties. Rain on Saturday put a halt to that progress.

Those figures don’t account for the 6 to 10 inches of rain that fell in late April across Illinois, Indiana, Ohio, Missouri and Kansas and replanting once or twice was necessary for many acres. Market analysts assumed the new seed would get delivered by the seed companies and replanted on time. Since then there have been areas where there have been no opportunities to replant. Now the replanting charts suggest that an even stand of 20 – 25K has more yield potential than a perfect stand planted around June 1.

It was time to pull out the old date of planting studies that have used numerous times in the last three decades. It was printed in the Wallace’s Farmer May issue showing the projected yield of stands from 10 – 45k as percent of maximum yield given planting windows from April 20 May 5 thru June 5-15. It is easy to compare between the different dates and pops. A person also needs to figure in his replant costs as well as fertilizer and herbicides that have already been applied and any expected insect or disease problems and costs for them. When making this decision to move to an earlier hybrid, the best chance of producing a decent yield requires corn growers to acquire any information showing the hybrid (s) possessing the ability to move south tolerating hotter summer temperatures and more disease pressure.

I’ve been at meetings where the Sec of Ag said their price support program was to pray for a crop failure in the states to the east and hope it doesn’t hit their area. In the case of 2017 markets there have been analysts who felt in their bones that an unexpected event was going to trigger higher commodity prices. If trend line yields aren’t produced, those able to get good yields could capitalize on weather events. It may be time to be more on offensive and try a few more yield boosting ideas and products on fields with good stands. Most of those in Iowa have good stands. Any U.S. corn acreage under 90 mil. is predicted so send a strong bull signal. Wet and cool still brings yield robbing diseases later in the season which could reduce yields even further.

Soybeans

There are still a high percent of soybean acres left to plant. The urgency to get them in the ground was not as great since the ground stayed cool thru May 20. The April planted beans emerged early but are still in the unifoliate growth stage. I have been in April planted fields near lots of CRP acres and trees where the plants were chewed up badly by the bean leaf beetles, enough to reach the treatment threshold (TT) because the beetles spread pod mottle virus. Test work showed this virus reduces bean yields by 17 percent alone or greater than 50 percent if combined with PMV. I have to check to see if those beans had systemic neo-Nics applied. Look for them on a sunny 72 degree day between 10 a.m. and 3 p.m. The skitterish beetles quickly dart into any cracks in the soil when disturbed, but leave signs of feeding damage to the leaves and cotyledons.

GDUs

We have fallen behind on GDUs and the worst time to do so is when vegetative growth is tops on the priority list for corn. The projected tasselling and filling period has been delayed by 10 to 15 days. Soybeans have to reach V5 before they can flower. In 2016 many corn fields were nearly knee high by June 4. This year as of May 28 the earliest planted corn late V3 to early V4. It should form two leaves per week and if with temps in the upper 80s could add 2.5 leaves per week. Most varieties will form 18 – 19 leaves total in an average growing season. In 2016 the average was 16 to 17. Thus a person can calculate how many weeks have to pass to grow the plant to VT.

The height of the plants planted in late May will be taller than April or early May corn by 18 to 24 inches. Those planted after June 5 stay shorter. With the taller plants come higher ear placement and stalks lacking in structural stalk strength. In a year with expectations for peak ECB populations the second brood needs to be monitored on a regular basis in conventional hybrids. Fresh pollen and fresh silks attract many insects including ECB moths and emerging CRW beetles.

Weed Control

Now when early post applications need to be made to corn, growers are pressed to find any time and dry soils to complete such work. The value of applying residual products to corn and beans becomes more apparent. Most Amide chemistries appear to be doing an acceptable job and will continue to give control. Many broadleaf weeds have emerged and will have to be sprayed within two weeks. The choice of products to use in corn includes a wide variety of products.

In soybeans the main emerged problem weed appears to be marestail. It emerges in late winter or early spring and is typically more of a problem in no-till fields. It has shown the ability to tolerate applications of several different herbicide families and can be tough to control. With this and now waterhemp plants choosing the accompanying surfactants can make a huge difference in degree of control. I was impressed with the SprayTec product results as they offered improved control while minimizing leaf burn. With too much oil the actives remain on the leaves which then fall off. Not enough get translocated into the plant to kill it and regrowth occurs. In dry weather it can take two to three weeks for new leaf tissue to form reducing the fill time period.

Haney and PLFA Testing

Because more growers are recognizing that the clearest path to higher yields and a major component to healthy crops are good soil health, as measured by the Haney or PLFA testing. The Haney or Solvita tested relies heavily on measuring the CO2 being respired by microbes. The PLFA (Polylipid Fatty Acid) test works by detecting and categorizing the soil microbe population by testing for the fats in their outer cell walls. It can do the same by testing for their chromosomal constituents (peptides).

Nitrogen losses and monitoring plant sufficiency

This is shaping up to possibly be a season where leached of nitrogen to deeper soil depth will make us question its presence or location. Buying a low priced ($269)’At Leaf Spad Meter’ to measure leaf greenness at all growth stages could be a good decision.

The V5 growth stage on corn will be here shortly. This is when mineral deficiencies become obvious and tissue or sap analysis test should be run on the leaf samples you have gathered/sent in. Herbicide applications of chelating herbicides also can factor into this. Be sure to request tests for Bo and Moly since those two minerals are important components in the plants’ metabolism. Recognize that cool and wet conditions when combined with mineral deficiencies are going to lead to fungal and bacterial diseases. Be thinking first about how the nutritional approach could help manage these problems. Then be planning what, if any, preventative could help, lastly what rescue chemistry would be effective.

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