Most growers with good memories can instantly recall the weird weather years in which storms, tornados, blizzards, floods or droughts ruled the weather and greatly determined how great or how poorly the crops responded. Weather, whether good or bad, wet or dry, sunny or cloudy, or cool, frigid or hot rules the day and, as it said determines the crowd size at our funerals. So how will we remember the 20-18 growing season? In trying to categorize it we might have to say “all of the above”. By late June people in the northern half of the state were wishing for the rain to quit for a while. Then we ended up with the 5th driest July on record in the central part of the state. North of Hwy 30 the rainfall amounts N of that line have been adequate and the crops received as much moisture as most of them needed. S of Hwy 30 the rainfall has been miniscule and this past week even more of the fields began or continued to give up the ghost, turn their ears down, and turn brown or tan.
I have yet to run into a knowledgeable crops person who believes the happy talk about the expected record yields. Instead most have driven far enough in different directions and gotten a first hand look at the different areas form their own opinion. We are continual told about how the surveys are being improved to lend more accuracy and up to date forecasts in them. Then why do they continue to predict huge corn and bean yields while we look at corn fields that were bright yellow and then brown in early August and bean fields still lacking in pods and decent node counts.
So far I have not seen any ears where the kernels have formed a black layer, but have seen some with a distinct brown layer. The moisture lines are moving down, confirming that the high 80 degree temperatures are speeding the development of the ear and kernels along and maybe two weeks ahead of last season. This reduction in the fill time could easily shorten the grain fill time by two to three weeks. This would point to a 20 to 25 percent reduction in fill season versus normal. Consider that the grain fill in 2016 ended on Sept 6th and last year there really no stress day of 90 degree temperatures with a strong south wind until October. This year every week of August so far has continued to have a few stress days North to Hwy 20.
Last week I mentioned that about 30 percent of the fields along and south of Hwy 30 were already brown or white with shrunken kernels and their ears flipped down. Having zero rainfall throughout the week sped up the crops physiological maturity timetable and pushed the corn plants closer to or into senescence.
In Missouri, much of southwest Iowa and In Kansas grain harvesting and silage making are beginning or well underway.
Between I80 and Hwy 20 the crops are now showing the effects of the heat lack of rain. More rings of kernels are disappearing at the ear tips and the dent is both earlier and deeper than anticipated. Reports from parts of Missouri are now telling of cases where the grain terminals are not accepting some loads due to underweight test weight.
During this dry spell many of the bean fields have held plants where the pods have stayed flat and need rain to puff those kernels up. The minerals most needed at this time to bolster grain matter fill are K, S and Mg. With the soils being very dry those minerals are more likely to be tightly held within the top few inches of soil and are not being transmitted to the bean plants.
About the only way for a no-till grower to get those minerals into the plant would be with a foliar application where the three minerals are included and the pH has been adjusted close to 5.5, or a Y-dropped application along with expected dews to carry it into the shallow feeder root zone.
As of early afternoon of Sunday Aug 19th there is a large front that stretches from near Clovis, New Mexico up to Mobridge, South Dakota that is getting closer and promises needed rain to the drier sections of the Midwest. It will be during our large Guthrie Center field day, which may limit the number of people touring the plots. But when the corn and bean plants on the lower ground are still green, but need rain to fill the grain, each inch of rain could contribute 12 to 14 Bu/A onto corn yields. We will gladly accept any moisture as it comes.
We walked the plots on Saturday afternoon, taking ear size measurements, noting plant and leaf color and sizes, and Spad readings to measure chlorophyll and N content. The different plots were treated with different fertilizers, additives, foliar fertilizer, plant health promoting compounds, and signaling or elicitor compounds. Just looking and measure ear size tells us we are going to see big differences at harvest time. When combined with plot results from other sites we should have enough information as to say ‘yeah or nay’ when advising farmers about using those products in future seasons. Our goal was to find products that would add to soil and plant health, minimize the effect of drought or heat stress, and boost fertilizer efficiency. We have about 5 new products on display versus last year, so it will be an exciting harvest.
We will be having the event recorded and could supply thumb drives with the program on it to people that could not attend.
Next week is the big Farm Progress Ag Show scheduled for the middle days of the week. It was moved up a month on the calendar years ago to avoid any conflicts with harvest, but with some of the combining in the drought areas and some silage chopping starting, there may be a few conflicts. So far the corn fields appear green enough around the site that harvest demos should be on schedule. May your visit go well if it is on your agenda.
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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