Consultant Bob Streit's fall crop update

By Bob Streit 

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

The Growing Season

October 1, 2021 After surviving the first part of the 2020 growing season where two thirds of the state had a substantial drought, then following it with the Aug 19th Derecho, many of us were quite apprehensive about what 2021 might bring. Would our moisture profile be filled with April rains; would sunshine be close to normal; how about GDU accumulation; and might strong Derechos blasting thru major crop growing areas become the norm? That leaves us questioning the ability and accuracy of the meteorologists we listen to each day when we listen to their forecasts. 

My view of the weather and what gets thrown at our crops was polluted by reading a few articles from James Franklin Lee and his column entitled China’s Mind Blowing Weather Modification. His web page gives the details and shows pictures of what the three major countries have developed in the arena of modification and management of weather on a regional and global scale. Each person has their own one or two climate forecaster who provide predictions and expected weather swings. Throw in any such manipulation and a person has to ask what is normal and which is not. One perspective not often mentioned is the effect of energy and solar eruptions on the surface of the sun. These influence what is going on the earth’s surface. Two good examples were ‘The Carrington Event from 1859’ and ‘Larger than the Carrington Event in 2011’. Those were twin and triplet flares which occurred in the 19th and 21st century. The first lit up the skies for 72 straight hours with enough electricity flowing across telegraph offices setting a number of them on fire. #2 was a triple flare jumping 135,000 miles off the sun’s surface and would have fried the grid if we had been one week further in our rotation.

Yields So Far - Soybeans

Most farmers are further ahead with bean harvest than with corn and have a better handle on yields. What most operators are seeing is yields are much better than anticipated in a summer that was hotter and drier than normal. Many fields never had rain clouds pass that dropped more than 1”. The lack of moisture stymied the development of fungal lesions to until late August or early September. The same dryness caused stress hormones to be produced, causing pod abortion while poor K uptake during seed fill tempered yields Commonly heard yield levels are in the mid 50s to high 60Bu/A range, and up to mid 70s, where rains fell. Much better than expected.

The beans that were highly managed for optimum bean size and health stayed green and filled longer and most of those have not been harvested yet. Looking at pod retention and seed size, the gamblers appear to have won their bet. 

Editor's note:  Here is an inserted comment from Renewable Farming, to offer an example of Bob's paragraph just above which mentioned "beans that were highly managed for optimum bean size and health..."  Please see the photo at the bottom of Bob's column. The photo was sent to Renewable Farming by a north central Iowa grower who "highly managed for optimum bean size and health." His combine monitor was registering soybean yields over 100 bu. in sections of a 160-acre field where soil types offered good biological activity and a full response to several season-long foliar nutrient and biological sprays. Best yield was a section of 120-bu. soybeans. In a low section of that field where soil was saturated in early spring and biological activity was drowned out, yields sagged. The point: Foliar-applied biological yield boosters work best where soil conditions can respond to season-long nutrient management.

Yields So Far – Corn

 Given the fact that many fields never had a general rain front or cloud pass over their location, getting any decent corn yields over 100 and even 150 Bu/A is totally amazing. The July 5th situation in central Iowa found many corn fields had their leaves rolled tight by 10 AM, had taken on the grayish color, and never seemed to get any moisture relief until August. The yields seen so far are very surprising. There are still fields that died very early due to root feeding or lighter soils and will be producing sub 100 Bu/A yields. Fields on more biologically active with higher OMs, and with adequate mineral supplies will be significantly. Some will be in the 220+ range.

What is surprising is that corn growers in states east of Iowa received much more rain, but are now disappointed in how their corn yields have been much lower than predicted by the Pro Farmer tour participants. It appears that our dry climate lessened the chance of fungal diseases increasing in incidence and severity. Some are speculating that one cold rain during the early V stages allowed crown rot pathogens to invade the crowns. Might they be able to plate crown tissue to see which if any root rots were present. They should also have growers and agronomist look at tissue test levels to see if any nutrient levels were low and see if any deficit in minerals can be correlated with higher incidence of foliar diseases.

One commodity advisor and analyst did a phone survey of growers and ag people who actually get into the fields. The horror stories of major disease issues becoming big yield reducers was too often true. They still have to develop the answers as to what happened. Were Mn-Bo-Cu-An-Fe- S, or Mo levels too low or not available if they gained entry into the plant? Was coverage lacking if applied by air? Were applications made during a time period of rising thermals? Were applications made too early or too late? Should two applications have been made? Are certain actives losing their long residual compared to a few years ago?

 Tar Spot

Our eastern neighbors are mentioning Tar Spot, GLS, Goss’s Wilt, Anthracnose and NCLB as being problems. Either one of those, if unchecked, can weaken plants to make them more susceptible to another disease. Right now guidance from an experienced pathologist may lead to her recommending two applications of Veltyma spaced three weeks apart.

I will have to travel to Wisconsin soon to check out 600 acres sprayed with mixes of two systemic products that have very long residuals. They looked great when I was out there last.

Post Harvest Plans

Now that harvest is here you may want to consider a disease control plan that begins with applying a microbial mix, like Meltdown, to aid in the biological degradation of corn residue this fall. Besides minimizing the amount of inoculum being carried into the 2022 crop, it will produce more rapid release of minerals held in those stalks and increasing water infiltration into the soil rather than washing off the field. Recognize that a number of these mixes have been or will include soil dwelling nitrogen fixers that turn atmospheric nitrogen into plant available N. At an ISU Lab Farm they have plats where Envita was applied to seed, in-furrow, or post emerge following a 120 or 140 lb. application at planting. As of late August those plots were all very dark green and looking great. 

This was the exception in that there were no heavy rains to cause leaching. But it is relevant in a year where the N prices are extremely high and extra nitrogen may not be available. Tackling this paradox become a surer science if you have at your disposal a SPAD meter to use in monitoring N levels in the plants at select times.

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

Yield monitor evidence of how "full-season management" described by Bob Streit can work for you. That's 109-bushel soybeans being harvested at 2 miles per hour.