It’s another week into the grain fill period and for about 75 percent of the farmers in Iowa the situation gets worse. We and the crops waited and waited and waited hoping for a major front to drop enough moisture on the ground with the 2 inch wide cracks so that the moisture demands of a decent looking crop could be met and we would be able to produce and harvest near trend line yields. More than a few growers saw how the degree of dryness was categorized as very dry, abnormally dry, early drought or mild drought, and the people making those ratings seemed to be smoking something, because one only has to take a quick look at many of the fields in the western half and much of southeast and south central Iowa that the corn crop in many of those areas is on its last legs.
A number of climatologists have been predicting rainfall being closer to normal beginning in the second week of the month, but those predictions don’t put more rain into the gauges or quench the thirst of the plants. The time to get the rain for many of the corn fields was two to three weeks ago and for the soybean fields it is now. And after viewing the crop status in the major corn growing states and recognizing that the Dakotas, Kansas and Nebraska are now growing many millions of acres and are no longer considered fringe, the shortfall in grain will be felt on many farms, in the grain handling channels, and when feed plans for the livestock across the country are being assembled.
If all the happy news is meant to scare farmers into selling early the buying parties have to realize that growers recognize the game that is being played. Meanwhile we all have to see what history can tell us about droughts that come from the west and northwest.
The corn crop
My travels last week took me first through northern Illinois to south of Peoria. The southern location is quite dry and any rains of more than .5 to .9 inches have been rare since planting. The tipping back of the ears is easy to see and thus far the kernel fill is shallow. The first denting of the kernels could be seen, which is ahead of schedule by several weeks. When this process begins the amount to kernels will enlarge becomes limited. Staying dry could cause more of the tip kernels to abort or get small enough that they may not be knocked off in the combine.
The fields along I-80 considered in northern Illinois look good but don’t look like record breakers. Kernel fill looks decent but only time will tell if the depth comes close to that seem in 2016. Being out there on June 10 and seeing so many acres of corn just in the V1 to V3 growth stage tells me it would have been silking around Aug. 1 and will be at risk of any early frost or being behind on grain fill if the corn crop dies around Aug, 18 to Aug. 25 as we have seen in recent years.
My travels later in the week took me west to around Storm Lake and west. Once I got about 5 miles west of Ft. Dodge and Humboldt the crop looked a lot drier with many fields partially brown, rolled leaves, shrunken in size and fired up as high as the ears. To me it sure looked like a drought. I didn’t get as far west as Remsen and LeMars where silage chopping has begun. That is a testament as to the state of the crop. The yields will be just a little below tend line yield by a few bushels. Quite a few and the degree will be determined over the next few weeks.
As to soybeans, the pod and branch counts look good, but nearly all the pods remain completely flat with no moisture to fill them and the minerals in the top soil no longer available due to ultra dry soils.
What was surprising was how much variation there was in the conditions of the plants in individual fields. So what variables exist or existed to cause one field to still look good and the next a half mile down the road to look poor?
If a person was the state medical examiner for each field what might be the cause of slight, moderate or extreme moisture stress? This might be worth considering as one looks toward 2018 if dry conditions remain. Things that come to mind would be:
1. Rotation as to corn following beans or following corn.
2. Depth of planting, tillage or any hard pan.
3. Potential compaction from last year’s harvest or created during a wet spring.
4. Genetic ability of that hybrid family to tolerate dry conditions.
5. I have seen the Artesian and AquaMax hybrids looking very good so far. Natural breeding using multiple traits looks good. There is no one drought gene.
6. Mineral status of the plant, in that sufficient mineral levels permit the plants to withstand drought conditions much better. In this arena the main soil fertility researcher in Brazil has uncovered the important role of two rarely mentioned minerals that are important in forming a deeper and fully functioning root system. These pewny, brown root systems that have become common in the last twenty years just don’t cut it in a dry year.
7. Higher organic matter and better biological activity meaning that higher levels of humus in the soil as well as microbial bodies serve as moisture reservoirs for late season dry spells. This is also where mycorrhizal fungal populations from long term no-till or seed inoculants such as Scheppelle’s VAM mix can help extract moisture soil from a wider area. What other microbe mixtures can help raise your Haney scores and convert residue into a larger soil sponge? Keep your ears open to field proven product that work well this season.
8. Better moisture infiltration because of residue cover or the use of gypsum to leave the top inch of soil more porous so it captures more of the rain that might fall is important. The better residue cover when no-tilling or strip tilling keeps soil temps cooler and lowers moisture demands.
9. One arena that will raise a few feathers, but as documented in work by a Brazilian PhD researcher working under a USDA/ARS researchers at a Midwest Land Grand University, trait insertions lower the water use efficiency of plants. More research should shed more light on this?
10. In an observation by perhaps the sharpest ag consultant I know, he speculates that certain pesticides may have decimated the soil microbial populations that are instrumental to high silicon availability which determines the structural integrity of the water conducting tissues in the corn plants.
As to item number10, I will be out in Utah and Idaho later this week looking at plots at the research farm of Redox Chemical Company. In documented work done both in North and South America, farmers and researchers create higher levels of drought tolerance and disease resistance in grass plants by applying foliar silicon in the correct form. By looking at the plants treated and untreated in a desert climate their managers have said we should see dramatic differences between those plants.
Diseases and insects
In field scouting I am finding very few serious fungal disease infections. Air delivered fungal spores generally need dew on the leaves to germinate and penetrate. We have not had much dew over 75 percent of the state. Those growers who have been receiving rain have to be alert to common and southern rust, GLS, Goss’s and Bacterial Leaf Streak and perhaps NCLB on corn and Septoria on soybean plants. If the weather in dry areas switches to a wet pattern the later maturity varieties may benefit from a late Strobe application.
Farmers with conventional corn planted need to be alert to second generation corn borer moths which are now flying and will be for another two weeks or so. Looking for the small egg masses on the leaf undersides in the middle of the plants is the best way to scout for them. Verification via light trap catches can help pinpoint when the heaviest flights are occurring. UNL may be the closest place still running light traps and posting the information.
One other insect that may eventually become a soybean pest is the Dectes stem borer. It is a 3/8 inch long, grayish black beetle that lays eggs in the soybean stems. Their larvae tunnel up, girdle and collapse the stems prior to harvest. They have been a pest in Kansas and Nebraska and were recently found in southeast South Dakota. A long egg laying period makes them tough to control.
Everyone needs to do their rain dance ASAP.
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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