Author: Jeremy Johnson, Agronomist
Soil Sampling
A significant number of soil samples have been submitted across the province this spring, likely driven by growers looking to optimize input costs wherever possible. Given the persistently cold soil conditions this season, it is advisable to include nitrate testing as part of the sampling program, as nitrogen mineralization has likely been delayed.
Many soil tests are also reporting low Boron (B) and Sulphur (S) levels. It is important to recognize that both B and S soil tests have limitations and are not accredited tests, meaning results should be interpreted carefully and within the context of crop responsiveness and field history.
Boron management requires particular caution, as the range between deficiency and toxicity is relatively narrow:
- 0.5 ppm = deficient
- 1.0 ppm = adequate
- 2.0 ppm = potentially toxic
Where soil tests indicate low B levels, crops such as alfalfa, corn, root vegetables, and canola are more likely to respond positively to Boron applications. Other crops are generally less responsive, even when soil test levels appear low.
In winter wheat, tissue test-driven Boron applications have not consistently demonstrated a documented yield response. Similarly, soybean research has shown only minimal yield increases that were not statistically significant following Boron applications based solely on tissue test results.
Sulphur testing should also be approached carefully. Accurate sulphate-S assessment requires a 12-inch soil sample depth. Standard 6-inch samples often underestimate available sulphur, which can lead to unnecessary or excessive S applications.
Forage Crops
Many rye and triticale forage fields have now been harvested and placed into bunkers or silos. Due to the advanced harvest timing — often prior to boot stage — forage quality is expected to be exceptionally high in energy relative to typical years. As a result, feed testing is highly recommended to properly balance rations and account for changes in nutritional composition.
These early-harvested fields are also at increased risk for compaction damage due to the wet spring conditions. Growers should consider management practices that help alleviate or minimize compaction impacts ahead of the next crop.
Winter Canola
Several growers have experienced frost events during the budding and flowering stages of winter canola, resulting in concerns regarding potential yield loss.
Fortunately, canola is generally quite frost tolerant. Unless temperatures remain below freezing for an extended duration, frost typically has minimal impact on buds. Flowers are somewhat more sensitive, and some flower abortion may occur following frost events.
In most situations, fields that experienced frost during flowering are expected to see only minor yield reductions.
IP Soybeans
Fields with significant fleabane pressure require an effective burndown strategy. The addition of 0.5 L/ac of 2,4-D Ester is recommended for adequate fleabane control, as the Ester formulation provides superior activity compared to amine formulations.
When using 2,4-D Ester in the tank mix, applications made immediately after planting are often safer than spraying immediately prior to planting. If less than 10 days separate application and planting, incorporated residue can increase the likelihood and severity of crop injury.
Proper application timing remains critical to balancing weed control and crop safety.
Winter Wheat
To date, stripe rust has not been widely confirmed across southern Ontario, although other rust species have been observed. Where rust symptoms are present and samples have not been submitted for diagnosis, fields should be re-scouted within three days. Rapid spread is a strong indicator that stripe rust may be present.
Stripe rust can spread extremely quickly under favorable conditions and should be addressed promptly once identified.
Winter wheat growth stages across southern Ontario currently range from GS 32–39, placing many fields at the tail end of T1 fungicide timing and approaching T2 application timing. With elevated daytime temperatures, crop staging can advance rapidly, making timely scouting and fungicide applications increasingly important.
Tillage
In some situations, high-speed disc operations have contributed to shallow compaction due to the shearing action created during tillage. This has resulted in a soil profile where the top 2 inches appear dry and fit for planting, while soils beneath remain cold and wet.
Planting into this lower “muck layer” can negatively impact emergence, and root development. Soybeans are particularly sensitive to poor seedbed conditions and can experience yield losses of up to 5 bu/ac under these circumstances.
Maintaining proper planting depth and avoiding sidewall or smear compaction will be critical this spring.
Insects
Large populations of Black Cutworm and Armyworm moths have recently been identified south of the Ontario border, which may indicate elevated pest pressure later this season as migration progresses northward.
High concentrations of Alfalfa Weevil have also been observed in some areas. Early and consistent scouting is essential to identify hotspots before significant feeding damage occurs.
Timely monitoring and threshold-based management decisions will be important throughout the coming weeks.
