Soil, Weeds & Weather: Takeaways From ’24

Monday, March 24, 2025

Agronomists Outline Strategies for The 2025 Season.

By Paul Hermans

There is so much emotion in farming that sometimes we forget what happened during the growing season. The 2024 growing season has come and gone. There are always a few things from the previous growing season we can learn from and apply to the next one.

I recently polled some fellow agronomists to see what big agronomic factors they would consider when preparing for the 2025 cropping season.

Here is a summary of those key agronomic ideas.

Soil condition over planting date

Delays in planting last spring had many growers wondering if they would ever get a crop planted. Early May rains caused delays. Looking at the science behind planting delays versus mudding the crop in shows us that patience always wins.

Research data would suggest we gain two to five per cent yield with earlier planting dates. Compare this to the impact of even emergence, where we can gain five to nine percent more yield. Uniform spacing within the row accounts for one to two per cent yield gain.

The take-home message is ‘do not mud the crop in.’ Focus on uniform plant emergence in corn. Patience wins the race every time. Is there a date when switching out of corn makes economic sense? Yes, but rarely does Mother Nature force us to make that call.

I looked at corn plot average yields, planting dates and what yields were, on average, from the first-planted to the last-planted corn plots across Eastern Ontario.

Interestingly enough, in 2024, we averaged the same yield in corn plots compared to the 2023 season. However, our planting window in 2024 was much longer and ran later into the calendar year.

Soybean plot averages were higher in 2024 compared to 2023. This occurred with a longer extended planting window and later planting dates. A crucial factor for this was weather and lower white mould pressure (I will discuss this later in this article). Planting date is more important in soybeans than corn. However, the principles of avoiding mudding the crop in still apply to soybeans.

Effective weed control

Across the board, effective weed control and sound management strategies were echoed by the Pioneer agronomists interviewed. Having a residual herbicide down early, followed by a post application, was voted the No. 1 strategy growers can utilize to achieve higher yields while fending off herbicide-resistant weeds.

Growers tell me this extra herbicide application costs more to the bottom line. Research work by Mike Cowbrough at OMAFA would suggest a two-pass system, compared to a one-pass system, achieves on average about 13 per cent more yield. This more than covers the extra costs of this herbicide pass while increasing yields, allowing growers to use multiple modes of action to assist in managing herbicide resistance.

A prime example of this is fleabane. In Eastern Ontario, we have observed a shift in weed pressure due to glyphosate-resistant biotypes and the continued use of just a one-pass herbicide system.

Weather and diseases

If you were to ask Albert Tenuta, OMAFA’s extension field crop pathologist, what the biggest influences on diseases in crops are, I am sure he would mention the disease triangle. All crop diseases result from interactions of three factors that make up the disease triangle: A pathogen, the right environment, and a susceptible host.

In Eastern Ontario, we had limited white mould in soybeans this year, following a high white mould year in 2023. Even with an increase in soybean on soybean planted acres planted in 2024 – a result of delayed corn planting and rotation changes. Looking at the environmental factors for disease incidence in white mould, key environmental conditions must be present during the critical flowering period of soybeans. This includes favourable weather and temperatures in the 20 to 26 C range.

During the 2024 growing season, during the last week of June and the first week of July, hot temperatures and reduced rainfall patterns decreased the risk for white mould.

Flipping to corn, tar spot was rampant across most of Southern Ontario and made its way east of Toronto into the Belleville area and into most regions of Quebec.

Why is this?

Again, looking at the disease triangle for tar spot, we had high incidences of leaf wetness greater than seven hours, which is key for tar spot development. The ‘new tar spot areas’ in Eastern Canada had hurricanes and major windstorms bringing spores in from both Southern Ontario and the U.S.

Going forward, crop models will help take some of the guesswork out of disease predictions. These tools will be a welcome addition in the agronomy toolbox as we battle diseases like tar spot and white mould down the road.

Well-balanced fertility plan

With tighter margins people may be thinking about cutting fertilizer. Caution: We need to feed our crop, especially considering the higher yields we have experienced over the last five years. An effective way to lower yields is to starve the crop of nutrients.

Look at soil test levels and do a field-by-field, or better yet, sub-field management zone strategy.

At bare minimum crop removal rates are encouraged.

The next step is variable rate fertility plan to achieve higher yields. Over the past two months I have had many enquiries on variable rate applications, including seeding and fertility. Placing the right product, at the right time, in the right form, on the right acre bodes well for higher yields.

Agronomists also advised that having reduced compaction allows crops to get to the fertilizer in the soil. Proper soil health and reduced compaction layers are vital to providing an optimal root zone where roots can reach their maximum size utilizing the nutrients available in the soil. Picking the right tillage tool if you are in a conventional system is important to avoid issues described above.

Trying to not sound like a broken record but … soil test, soil test, soil test. At a minimum, soil tests should be taken every three years with some form of geo referenced system so you can compare changes over time.

In most regions of Ontario and Quebec there are still large livestock operations present. The utilization of manure in a timely fashion aids in the reduction of fertilizer requirements while increasing organic matter and improving soil health. One common comment from my counterparts was that there is a need to do more sampling of manure to get true nutrient values of manure to accurately offset fertilizer inputs and costs.

Every year has its up and downs. Looking back to the roller coaster ride of 2024 helps us become better agronomists and crop managers. As we enter March and spring approaches, take some time to review the 2024 season – what worked and what did not? – as you make plans for the upcoming season. BF