Renewable Farming

Corn used to be one of our healthiest crops. Now what?

Here’s a summary of crop consultant Bob Streit’s observations as August wound down — and the suspense is building:  How will corn and soybean health hang in there without robbing what (until now) has looked like a huge crop?  This is Bob’s take on it in his report to clients:


August is over with and harvest will be here before we know it. It seems like just yesterday we were getting the equipment ready for the spring work and wondering what the optimum time to start field work was going to be. March was so warm that we could not quite believe the snow would disappear so quickly. Everyone was in the mood to get things started early and get as much done as quickly as possible. Everything seemed so early, and then reality hit us in the face with a cool, wet late April and a very wet May. The planting season that started so early quietly morphed into a long drawn out battle with Mother Nature. Farmers gradually got all the crops in but it took until early June before the planters would be parked for the first time. Many had to pull their planters into the fields once or twice more to replant the low areas in many fields.

Crop Size

We have seen the USDA crop production prediction numbers as well as the results of the Pro Farmer Crop tour. Who do we believe? So far what I have seen is that nearly every grower, especially those who walk their fields or operate a high clearance sprayer and got a bird’s eye view of the crop, believe the numbers are too high. They have a variety of reasons for those thoughts. First of all the prognosticators seem to have forgotten how hot the daytime and nighttime temperatures were in June and July. Heat early can be a good thing in that GDUs are needed for plant growth, but high temps demand adequate moisture to keep the plants from getting moisture stressed. In about three-fourths of Iowa it was extremely dry until mid July. The corn leaves rolled severely with many of the plants showing signs of the proteins being denatured and being extremely stressed. Similar heat returned when the plants were in the early grain fill stages. The heat was a factor during both the day and at night, which is poor for grain fill. Where are the experts factoring in those negatives?

Two questions that should be asked of any person who helps on the crop surveys or supplies info for the NASS figures are:

1. The USDA percentage of the bean crop rated Good to Excellent for soybeans in Iowa in early July was 82%. Now we see many fields with major problems because yield-cutting SDS is infecting plants. Since we know that SDS can be a major yield robber, why does the Good to Excellent category for Iowa soybeans stay at 82%. Where is the SDS accounted for?

2. How many NASS statisticians have flown over the crop in a small plane at a low altitude in late July to late August to see all the warts in the crops? Both crops can and do look good from the road, but show a much different face when viewed from above.

I had the opportunity, courtesy of a Webster Co Farmer, to take a leisurely two-hour flight over several counties in central Iowa on Monday. All bad spots and problems are fully visible. Poor stands, Goss’s Wilt, SDS, greensnap, lost or misapplied N, planter or clutch problems, drowned out areas and twice replanted ponds are all highly visible. Nothing can be hidden from the air while it is often hidden from the road. Given, we were over an area with glacial till soils where water can stand and cause problems, but pilots and growers from other areas are thinking the same thing. The goal of the record high yield predictions seems to be to cast a negative light on prices for commercial interest. There will be some big yields. But there will also be disappointing yields for many growers for reasons that were often out of their control.  

Brown and Not Green Crops

I have continually harped on the fact that the corn crop has been dying 4 to 6 weeks early the last 7 years and predicting it would happen again this year. Well, what is it doing this year? Play it again Sam. Then we hear the ridiculous rantings about it being the new normal and see the guidebooks where the authors sub substitute a disease picture showing diseased plants as the new normal.

Give us a break. Just like in humans and animals, most diseases occur because the patient lacks the minerals to maintain a fully function immune system response. Chronic shortages of important minerals create chronic diseases. Fields that were managed for a complete mineral profile are the fields that have stayed greener, will have a healthy stalk thru harvest and should put more grain in the bin.

From the air we saw the circular spots in the brown corn fields where the disease spread outwards from the epicenter. Right now there are more corn fields that show a ghastly shade of yellow than are dark green. There are also fields where the top leaves have turned a copper color. This can be some cannibalization of those leaves as the plants are scavenging for nitrogen. The text books still state that the first leaves to turn brown on healthy plants are the leaves that form the husks.


The symptoms of SDS continue to worsen in infected fields. Also over the area we flew it was common to see where 50% or more of the area in many fields was going to be affected by the leaf scald disease. Wetter areas and sidehills seemed to be most affected. Those areas were either more saturated or had the valuable nutrients eroded away over the years.

Because the seed-applied fungicide that solution-seeking-growers had applied to their seed did not last thru the season, as it was never guaranteed to, those bean farmers will be asking what their next step might be. A new paper out of a research group in Argentina gave the details of their study where they applied a mineral mix of Cu, Mn and sometimes Zn along with a phosphite plus a Pseudomonas fl and saw season long control of a problem disease. Research in the UK using a similar mix also showed good results.

In examining farmer’s SDS problems the approach has to consider that if they are fighting a biological battle they need to involve a proven microbe, which is the Pseudomonas fl. ISU scientist acknowledge that this bacteria produces multiple compounds that kill the Fusarium fungus.

 Conservation Acres

I happened to attend a rural estate auction last weekend and guess what the topic of conversation was? About how they and many neighbors were offered the chance to enter wet and unprofitable acres into CRP type and pollinator plots. The payments seemed very attractive given the low commodity prices. Now they have received the notice that a portion of the seed which was government-approved for the plots was contaminated with Palmer Amaranth. Now they are supposed to scout the entire fields vigilantly to see if any tall pigweed type plants show up. The territory we flew over today contained lots of 80 to 160 to 320 acre tracts. Being able to identify any Palmer in such a large field is going to be very difficult. Walking those fields is not something they are looking forward to doing. I won’t mention some of their comments.

By Bob Streit, crop consultant, Sept. 1, 2016         515-709-0143