After the 2018 and 2019 seasons when planting was delayed for most Midwest crop producers and rain washed out some of their best laid plans they were hoping for a ‘normal’ season where the planting season went well, the GDUs were adequate, and the rainfall came at the right times and in normal amounts. It has not worked out that way for the producers in many of the cornbelt states. We sit at the end of the first week in September, with both the corn and bean crops succumbing to lack of moisture across an area from SW Colorado and east into Pennsylvania. It will be a month now since the inland hurricane blew through with a fury unseen by any living person outside those who lived thru the Midwest F5 twisters. The towns, cities and farms are still cleaning up from the storm that destroyed crops, bins and buildings. In a few instances the insurance companies have begun to settle claims and recommend to growers as to what should be done to flat or semi-flat fields. Farmers in the central one third of the state are apprehensive about this upcoming harvest which they know will be long and stressful as tackle the combining of partially or fully lodged plants that will be waving wildly as they move up the snouts in a dizzying fashion.
Someone reminded me on July 12th that it was the 49th anniversary of an F2 twister hitting my home farm back in 1971. I was an active participant as I had to outrun it on foot and hang on to a fencepost in the swirling debris as it knocked down one grove and two silos while sending five building skyward. I had nightmares every night the next few months and woke up thinking it was just a dream, until I look out to see the place all torn up. That same feeling has to be how many people from Carroll to Davenport have to feel as they pick up the pieces.
As to how the combination of drought and the derecho might affect the national crop yields most people in the Ag world believe the outside marketing people under estimate how the lack of rain from June thru September have impacted the crops. Now with the corn reaching blacklayer and the beans yellowing and dropping leaves there is a finality to the growing season. All of their modeling assumed that moisture conditions in the late summer will return to normal and the plants would recover from early season dryness. Not this year. For the many fields where corn stalks are bent or laid down in multiple directions the bushels left in the field could be much greater than thought. If growers have a choice of having to harvest a field laid flat in 30 – 50% of the area, with the remainder leaning bad enough that one direction combining will be required, or having the field totaled most operators would just as soon disk it under and collect the crop insurance check, especially if their storage facilities are gone now. In recent days we are seeing more fields rolled or disked. The bushels not harvested could well be 300 to 400% of the forecast.
Late Season Cropping Issues
Walking into a derecho lodged corn fields is akin to sticking your finger into a Chinese finger trap as walking against a thick stand of plants pointing towards you is nearly impossible. In a high % of the badly lodged fields the plants turned brown as a combination of dry soils and ripped off roots left them unable to access non-existent moisture. Having temps in the high 80ss to mid-90s exceeded what the plants could endure and they died. The smell of plant death has been in the air in recent evenings.
The kernels have been forming their brown or black layer, so grain fill is over with. The ear sizes in the driest areas have been reduced and range from 14-18 by 28 to 38 long. In parts of the state where decent rains fell the yields will be decent to good. Parts of N and NE Iowa will have the best crops. Kernel depth in general is reduced compared to that seen in 2018 and 2019. Again full season plant health was important to an optimum grain fill period.
A high % of the fields turned an off to bright yellow color before browning. Part of the yellowing was due to Anthracnose die back while in other cases was due to the plant having to denature the protein in the upper leaves as it scavenged for nitrogen late in the season. Families of hybrids that form shallower root systems demonstrated that such a characteristic was a large negative in a dry season. Goss’s Wilt susceptibility was another noticeable factor in stay green and final kernels fill.
The arrival of Southern Corn Rust spores and lesions were noted in Extension Newsletters for growers in Nebraska and S Dakota during late July and early August. The severity of the disease increased in irrigated fields and areas where rainfall amounts were meaningful. Rust lesions increase when moisture films persist on the leaf surfaces. The Southern version can cause an entire field to turn from having a few lesions to completely brown in eight to ten days, reducing yields by double digits. I pulled the trigger recently on some irrigated acres 1.5 hours south of Iowa City where we sprayed with a systemic mineral product that shows great promise with its curative activity. I plan to head down to see those fields this week to check on the treatment results.
Late Season Insect Issues
In general aphids have not been a major problem the last three years. In parts of NW Iowa there have been scattered fields which for unknown reason attracted very high populations (>2,000 per plant) of aphids two weeks ago. A few of these fields were soybeans and the soybean aphid populations suddenly exploded to numbers way above treatment thresholds. Other places that held high aphid counts were several corn fields. Their populations increased enough that sooty mold growth was so heavy the center leaves turned black and sticky. Very little research has been conducted in the last few decades on corn aphids so establishing treatment thresholds is a guessing game. In the past dry years we have seen cases where heavily affected plants corn was sprayed and certain varieties showed yield increases of 20+ Bu/A.
Nematodes
I had the opportunity to visit with a knowledgeable Ag professional who farms and works with growers who raise irrigated potatoes and sugar beets out in Idaho. Due to the constant threat from damaging cyst and root know nematode populations the average grower spends about $300 per acre for an application of Telone, plus another $200/A for Vydate, a carbamate with a low LD50. By learning from and working with a nematologist from WA State they have learned that they can use the GDU accumulation, as given for their area by Corteva, to recognize when the nematode eggs will hatch and root feeding will increase. There are two products sold by this Georgia based company (Organisan or O2YS), one being a mix of chitin and the other being a knockdown insecticide from a Chilean tree, that have proven to be effective in dissolving the egg cases and the larvae, resulting in residual control of the different stages of the parasite at a fraction of the cost of the hard chemistry. Might this program work here with our SCN?
Recommendations tor Terminated Fields
In the last two weeks we have begun to see fields that have been terminated using either a roller or a large disc after being given clearance by their insurance agent. The question by many growers has been “what is considered the optimum program to turn this disaster into something that could help improve the soil for future years?” Many recommendations given by experts center on chopping silage, but with fewer feedlots around the option is out. After talking to a few colleagues our recs follow two paths, with the variable being if the ground is erosion prone or not. If erosion is an issue the downed corn could be disked to cut the stalks into smaller pieces, then sprayed with a microbial mix such as BioDyne’s Meltdown, containing 29 species of lignin degrading microbes, allowed to incubate for seven to ten days, and disked again to blend the stalks into the soil, which eventually should get rained on. On flat ground the common program used by the organic growers has been to moldboard plow and level the ground with a tined bar attachment, then plant a cover crop that will protect against erosion and build the microbial populations in the soil. The two most commonly recommended cover crops would be oats or rye. Oats will freeze out during the winter plus improve soil tilth while also making Silicon more available. The oat residue would allow for both corn and beans being no-till planted next spring. The rye will survive the winter and its roots will penetrate deeper into the soil. The rye crop could be harvested as hay or forage next spring, or terminated in the best method available. The thick thatch and straw has proven to be a good deterrent to weed germination and growth. (I saw back in 1971 the huge beneficial effect from working in a living crop that shows up for the next four or five years) Rain will be needed to allow germination of all seeds.
Next Level Ag Labs – Alpena, S Dakota
One pertinent question by leading farmers focused on optimum yields and profits is “How should they make decisions on fertility based on tissue and sap analysis they have either been doing or acknowledge they need to start doing?” In many operations the macro-nutrient levels are good, but there has been no strong guidance from their normal fertilizer retailer or their Ag University covering their crop’s micro-nutrients needs or sufficiency. A number of high yield growers have questioned if the recommendation charts are valid or left lacking. The second question is “How much work has been done to verify thru follow up testing that the minerals entered the plant and moved thru the entire vascular system, especially to the areas of need?” Are EDTA or sugars the optimum chelating agents, or will phosphites and amino acids be the preferred choice? If the foliar trials performed by any group or company were done in a faulty or inadequate manner, will they redo their work using what has been learned by successful growers or researchers?”
At the BioDyne/Wells Ag meeting in Davenport meeting last week several top fertility people revealed what their testing has revealed. I know of only one other collection of data like this has ever been made and publicized, although it was not available to the farming public. The work was done at Michigan State in cooperation with the Atomic Energy Commission in the 1955 thru 1965 era. I will cover more of this in the future.
Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143 or www.CentralIowaAg.com.