By Jonathan Zettler CPA, CMA, CCA-ON and Patrick Lynch CCA-ON

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Crop Conditions

Weather - last 7 days of so have been sunny and hot. Great for drying down crops. Then on Tuesday some areas got a lot of rain. We have had enough moisture across Ontario to get the wheat off to a good start. This weather is conducive to aphids in the wheat spreading Barley Yellow Dwarf virus (BYD). But most varieties have good tolerance to BYD (we did see increased incidence of it in the 2025 wheat crop, check for aphids in your wheat).

Things to do This Week

Things to Do This Week

1.      Review marketing plan for corn and soybeans.

2.     Check winter wheat emergence and weeds. Check for aphids.

3.     Plan termination of cover crop.

4.     Do population counts in your corn hybrid plots that will be harvested for comparison. You want to make sure you are measuring hybrid differences not differences in population.

5.     Check for corn ear moulds.

6.     Plan fall fertilizer. More time to spread fertilizer in the fall than in the spring. More time for VR scripting and safer for high rates of potash if they are being applied.

Soybeans

Harvest is not very pretty this year. Probably the worst harvest in the current era of soybean production in Ontario. Early planted beans harvested early were not bad if you received rain. But the last two weeks has been somewhere between not good and awful. Yields are so-so but moisture is low. One grower commented that moisture is really low but higher number than yields. And the harvest is dustier and dirties than anyone can remember. The issue is saprophytic fungi that have built up. These fungi break down residues. That is what they are supposed to do, otherwise we would have many feet of crop residue on the land. They break down residue after the plant dies. They are decomposers and include Alternaria, Diaporthe and Fusarium. They do not initiate disease in living plants but colonize and digest dead organic matter such as soybean leaves, stems, and pods. They help return nutrients to the soil. And this year we had ideal conditions for them to multiply. The spores of these organisms are in the air, and all over the place, they land on dead tissue. Some of this dead tissue was due to early maturation of soybeans. Then we had moisture to really get them going, then heat. Ideal environment for these fungi.

The biggest issue is the material they will leave in combines. These small particles are like flour dust in a flour mill. Any heat and they can easily start to burn. Combine fires are more apt to happen under these conditions. Be sure to have lots of fire extinguishers and use air to blow off buildup around any part of the combine that gets heated. Parts of the engine, bearings that heat etc.

One reader commented that growers in his are trying to combine from 9 in the morning until 1:00 pm when the moisture really starts to drop. Not much more that you can do. There are some growers done so there maybe be extra combines available in your area. Spreading soybean residue is harder this year than other years. A number of growers are resorting to some tillage after soybean harvest to get rid of the trash that was not spread evenly.

What to look for when choosing a soybean variety

(PJL and JZ)

1.      Maturity (earlier than full season if planting winter wheat or planting into a mould prone field) – use the Ontario Soybean Trials to see how maturity vs yield compares for your area. Timing of rain can impact these trials relative to maturity depending on the year.

2.     Herbicide tolerance. This means you have to know your weed spectrum.

3.     Disease spectrum. Specifically, phytophthora and SDS resistance. (Is it in the field you are planting?)

4.     SCN - how bad is SCN in your field?

5.     White mould tolerance - after SDS/SCN this is the number one yield robber.

6.     Yield, but this is not as important as the other factors since all the other factors affect your yield.

7.     Planting date – if planting early, plant a longer than normal maturity for your area. There is minimal benefit to planting early if you do not increase your maturity slightly beyond what you would normally plant for acres going to wheat.

8.     Match soybean canopy size (bushy, semi-bush, slender) to row width/management/soil type.

Sample now for Soybean Cyst Nematodes (SCN) (JZ)

SCN is spreading across Ontario. August is the best time to sample. Now is the 2^nd best time before ordering seed and seed treatment. You can do a general test by splitting your soil sample that you are taking for nutrient levels and having one part tested for SCN. In major SCN areas it is suggested that you sample for SCN in fields that will be planted to soybeans in 2026. Or, if you have an area in your soybean field that did not yield as well as you thought it should, sample that area separately.

Understanding your SCN test results.

There are two items reported on SCN soil test results. Cysts and Eggs.

Cereals

Thoughts on using 2,4-D in the fall for in-crop winter wheat weed control? (JZ)

1.      It is not labelled

2.     Grain yield reductions of 14-24% based on Ontario research vs untreated or using crop safe products

3.     There are better products on the market for the weeds typically present during the fall application of winter wheat.

Chart from https://fieldcropnews.com/2016/10/should-24-d-be-used-to-control-weeds-in-emerged-winter-wheat-during-the-fall/ check out this page if you would like more background and information on this research.

Fertility

Red clover value if ploughed down (PJL)

Q If I harvest red clover that I under seeded in winter wheat is there still a nitrogen credit for next year’s crop?

Ans, I have searched through various research articles. The research is a bit vague. There is nitrogen in both the roots and top growth of red clover. The top growth contains nitrogen but also carbon so some of the nitrogen is tied up. The nitrogen in the nodules is more available to next year’s crop. But the total nitrogen credit from a red clover plough down, in the various research reports is for 50-100 lbs actual nitrogen. The weather plays an important role. If you terminate red clover in the fall the nitrogen is available sooner than if you terminate it in the spring. You need rain and heat to break down the plant to have nitrogen available. This slow release of nitrogen is why I give a nitrogen credit of 50 lbs/acre to the following crop of corn but no value to winter wheat. The nitrogen is not released in time for winter wheat. I believe there is 50 pounds of available nitrogen from the roots even if you harvest the crop.

Q Patrick, one of my customers sent me this picture. He worked the ground after wheat harvest and then planted alfalfa and grass. He obviously did not spray off the volunteer wheat. What should he do now?

Ans (PJL)

He has no choice but to spray off the wheat now. He will also kill the grass that he planted. It is too late to plant grass now so will have to reseed grass real early next spring.

Q From a reader. One of my customers had a custom sprayer spray the volunteer wheat in his summer seeding of alfalfa plus grass, but did not indicate it would kill the new seeding grass. What do you think?

Ans (PJL)

That is unfortunate. The herbicide to kill wheat will also kill the seeded grass. I would check and see if there is a late flush of grass. And check again next spring but he will probably have to reseed the grass next spring.

How much nitrogen does corn need after alfalfa (PJL)

Notes from University of Minnesota, (Minnesota is the 5^th largest corn producing state in the US)

Alfalfa–corn rotations offer a valuable opportunity to significantly reduce or eliminate a major production cost — nitrogen (N) — without sacrificing corn yield. To help growers fully capitalize on alfalfa’s N‑credit potential, land‑grant universities have developed decision tools that help mitigate the economic risk of under‑fertilization when applying little or zero N.

Field trials throughout the Upper Midwest show that, when alfalfa stands are terminated, they typically eliminate the need for supplemental fertilizer or manure N in the first year of corn — with certain caveats. Exceptions occur on sandy soils, on clayey soils under prolonged, wet early‑season conditions, and in medium‑textured soils when alfalfa is terminated in the spring.

Alfalfa also frequently (in about half of observed cases) eliminates the N requirement for second‑year corn.

Fertility

What should I use for removal rates? (JZ)

When it comes to rates, I like to use either the Ohio State University or the Ontario rates (Agronomy Guide - Publication 811). I tend to shy away from using removal rates generated from other areas of North America, as they are not consistent with our soils/growing conditions, which may have resulted in luxury consumption.

Precision Ag

Precision Ag Notes (JZ)

Last week I had the opportunity to be a guest speaker at John Sulik’s Precision Ag class at the University of Guelph, here is a Coles Notes summary from my presentation.

1.      Like many of my peers, I am an agronomist practicing the use of GIS tools, while we help our clients make better decisions using precision ag tools, in many ways we still rely on GIS specialists to do our work.

2.     When it comes to thinking about variable rates, focus on the big rocks in the crop input budget to adjust. In corn, this is seed and nitrogen rates. Much of the industry has focused on P&K and Lime, which may still have variability but are also a smaller part of the input budget. You should rank your inputs and fields by where there is a mismatch in rates vs. flat rate figure out where to focus. Will need a soil test to do this.

3.     You need to vary your rates by more than the noise generated by the machine. i.e., most equipment can hold an applied rate within 5-10% of the target rate. You need to vary by more than that to actually adjust the rate beyond normal machine performance.

4.     As you scale the VR capabilities on the farm, how do you remove unneeded decisions from the process? Can you build ranges into recommendations rather than getting lost in the data?

5.    Fundamentals are fundamentals for a reason. Master them.

6.     There are times you will spend money to acquire data to determine how much variability there is in the field, but it may not be worth trying to adjust for (i.e., cheaper to flat rate and no additional crop response). That is okay. i.e., low fertility fields just need more fertilizer, which may not make sense to VR the rates.

7.     What does digital agriculture mean to me? It is the ability to lever my knowledge into a greater number of decisions/acres vs the old pen and paper method and reduce the friction in sharing information with my clients.

Life is not a matter of holding good cards, but of playing a poor hand well.

-Robert Louis Stevenson