Renewable Farming

Crop watch: Rain makes fungus grow too, notes consultant Streit

By Bob Streit Sept. 26, 2016 — Early harvest has started and in most cases is being delayed due to very wet soils. Rains amounts of up to 16 in. in the past week fell in parts of the Midwest, with the worst being in NE Iowa.
1. Very few people who walked corn fields this season believe the USDA/NASS corn yield figures. There were too many weather challenges this season that worked to limit plant growth and overal yields.  The exception would be with the growers who did their best to boost plant health. These fields stayed greener longer and grain fill in them is looking great. See the Schwartz story for details with one grower who went to extremes to push our knowledge boundary.
So far here is what I have been hearing.
Yields in NW IA: corn is about 20-30 Bu/A less than expected.
               SW IA. not much taken out but less than projected due to early death
               Illinois: their expected yields of 250 to 270 are turning out to be 210 to 225
               MO: where the mineral and BE applications were made yields are very good and up to expectations
               IND: from 100 to 200 with no clear trend obvious. Another tough year.
SB yields so far: pod counts after the leaves fell off are very good. Best I have heard so far have been 79 in central IA. High fertility, foliars and management paid.    
3. We began working with JR Santos this summer after we were referred to him as he worked to get his Brazilian company’s products introduced. We have been impressed so far. Combining their nutrient based products and biologicals there is great promise in working to control diseases without using so many fungicides. They have many trials with both growers and at Universities with good looking results so far. They are planning a November workshop in DM. I will try to keep you posted. I have included a PPT from their team. The advantages with this approach are: cheaper costs, longer effectiveness, preservation of the regular fungicides effectiveness by having less reliance on them, better results in disease control. 

After a large percentage of the state endured a wet May, a very dry June and early July, a very rainy last half of July and August, September may well end up going into the record books as one of the wettest on record. The poor citizens from different parts of NE and eastern Iowa have gotten pounded with rainfall amounts of up to 15 inches in the last week. Unfortunately Rule #2 in plumbing says that water runs downhill, so many towns and cities along the Cedar River have to endure another round of flooding similar to recent years. Sand bagging , cleaning out mud, and repairing the damage is what they will be faced with after the waters recede. Many of the crop acres have been harmed by running water with plants now tougher to harvest.

In a related note, in September we had the chance to listen to a presentation by a scientist from the National Lab for the Soil and Environment. His team is focused on soil health and its factors of nitrogen management and water retention. Here’s what worries him and fuels his thoughts: Many Iowa soils and fields can now hold as little as one inch of rain before run-off begins. In comparison Gabe Brown’s fields of small grain, pasture or cover crops hold an 8-in. rain without eroding. Now when we get a 3, 4 or 13.6-in. rain on sloping ground, many towns downstream have problems.

The first combines have been running where conditions are dry enough. The early reports tell of corn that is yielding double digit bushels under last year and also below what was expected by traders. Soybeans are doing better than people thought. The people who actually walked the fields knew that the record bushels predicted were never there. So much for the accuracy of modeling. The aerial vegetation index ratings from late July through mid August predicted the same shortfall in production. While that will be disappointing to individuals most growers are hoping that nationwide yields fall below expectations since a 15 bu. per acre corn shortfall is predicted to cut the burdensome carryout by half.


Soybean Podding

Soybean yields are still tough to predict. What has become more apparent after the leaves have abscised is that podded node count might be the best we have seen with the same trend showing up on branch number. The higher podded node count is typically more common with early planted beans, but not common with beans planted after May 20th. Lots of the bean plants grew tall and formed a few nodes more than normal. Usually if bean plants produce 17 to 19 podded nodes, yields of 60 to 65 Bu/A can be expected. This year those counts are very common. Then we have seen that the more recently commercialized varieties often form three to five side branches. These additional side branches add more podded nodes without contributing to plant height and accompanying lodging problems.

I talked to Keith this morning in eastern Iowa and he had found some Apex plants that had formed 31 podded nodes on the main stem, which is 5 more than I saw in Kip’s agronomist’s Apex plants. The deciding factor will likely be if full and adequate nutrition was present in the field to keep the plant supplied with the minerals needed for grain fill and pod fill. The early yellowing and damage from SDS will have its normal effect of lowering yields by 15 to 20 Bus/A.    

Corn Yields

A few things can be learned by going down a corn row, pulling the husks back and examining the tightness of the kernels, their shapes, seeing if there was much tip back and looking for any ear molds. Most of the fields that showed leaves that were streaking, indicating one or multiple nutrient deficiencies, were the fields that died early from disease. Many of those plants showed noticeable tip back from kernels that aborted due to less green tissue to form the photosynthates to fill the kernels, looser kernels due to the kernels having shrunk, and kernels that show a deep dent. In comparison, ears on plants that stayed green until mid to late Sept are very firm and heavy with little to no dent.

Poor grain quality appears to be an increasing issue. Docks of 5% at elevators are now common and could increase in amount due to Diplodia and other fungi. Excessive rains and weathering coupled with ears that often stayed upright created an environment conducive to fungal growth.  

Stalk quality is becoming an issue in certain fields, in particular where the plants have been dead already for a month or more. It is normal for soil microbes to degrade residue. Dead stalks can be considered residue and are more prone to pre-harvest stalk degradation based on when the plant died and the late season plant health. The course of action now is to inspect all fields for soft stalks, especially hybrids rated as having questionable stalk strength. Any fields known to have been attacked by Clavibacter are especially prone to stalk rots. Fusarium will also be problematic

Last week I mentioned several corn fields near Guthrie Center that were managed very well for soil and plant health. The grower’s cropping program in his very disease fields included in-furrow and foliar micronutrients, hormonal triggering compounds, the new Bio Empruv plant health product, and nitrogen stabilizers with the pre and sidedressed N. As of 6:47 PM Monday evening Sept 26, the plants on that farm were still green and have been adding extra bushels for about 20 days beyond neighboring fields. It will be interesting to study and understand how each of those products interacted to produce the favorable and profitable results. Check our website for Jerry Carlson’s recent article on this.

Editor’s note: Direct access to the article Bob references is at this link:  


Non-Bt Acres in 2017

Due to better plant health observations and budget limitations, there is a high likelihood that more acres will be planted to conventional hybrids in 2017.

That is all dandy, but too many growers seem to have forgotten that those acres will need to be scouted for European corn borer shotholes, eggs and early tunneling from both the first and second brood infestations. ISU’s Bill Showers and Les Lewis long ago realized the five year cycle in their population was caused by the presence of a fungus and a protozoa that parasitized the overwintering larvae. Make sure if you are planting such hybrids next year that you re-educate yourself on this insect pest’s life cycle, how to scout for them, and are then able to calculate the economic thresholds that good IPM standards dictate. Negligence concerning this pest could get costly as 2017 is due to be a peak year for this insect pest.

Soil Sampling

As you sit waiting for the fields to dry it would be a great time to look over your records to see which of your fields are up for soil sampling this fall. Having that current information and being equipped with a complete analysis including base saturation and micronutrients is the best information every crop farmer can assemble in deciding what fertility products and programs are needed for determining their 2017 plans. If you have not done this year, try to get prepared. Know which if any inputs or programs need to be changed to add greater returns.

 The Plant Disease Situation

While attending a genetics field day last week, I pulled a few corn leaves to put them under a magnifying glass to view all of the major diseases on them. Each square centimeter was covered with multiple serious diseases, some fungal and some bacterial. The warm and wet conditions of September created an incubation chamber in most fields.

While there are many advertised products, there are only three major hard chemistry families to choose from. We are likely to see overuse of those families result in resistance problems. As a counter to that trend there are trials underway in test plots and in university trials this year where mineral mixes were applied in-furrow or foliarly with results looking as good as or superior to the fungicides. This included those mineral/amino acid mixes being compared to strobe mixes on corn to control foliar diseases and on soybeans to fend off SDS. Checking for their effectiveness and having them available for famers to use in the future is the best insurance against fungicide resistance and harming soil health.  

Crop Consultant Bob Streit   Sept. 26, 2016    (515) 432-0907