Soybeans
Soybeans are the most widely grown field crops in Ontario and are a key part of many crop rotations. On an average year approximately three million acres of soybeans are grown in Ontario. They were originally introduced to Ontario as a forage species by Charles A. Zavitz of the Ontario Agricultural College, referred to as the “Father of Soybeans in Canada”. What sets soybeans apart from corn & soybeans is their ability to fix atmospheric nitrogen.
Soybeans follow vegetative (V) and reproductive (R) growth stages
- Vegetative stages (VE to Vn): Emergence through canopy development
- Reproductive stages (R1 to R8): flowering through full maturity
Key periods that influence yield include emergence and stand establishment, flowering and pod set, and seed fill. Stress during flowering and pod development can reduce yield, especially under hot and/or dry conditions.
Soybean performance is influenced by several factors:
- Planting conditions – Soil temperature, moisture, and seedbed preparation affect emergence and early growth
- Soil properties – Texture, drainage, and structure influence root development and water availability
- Weather conditions – Rainfall and temperature during flowering and pod fill are especially important
- Plant population and spacing – Seeding rate and row width affect canopy closure and light interception
- Weed control – Early-season competition can reduce yield potential if not managed effectively
As mentioned, soybeans have the ability to fix atmospheric nitrogen through a symbiotic relationship with rhizobia bacteria. Important considerations include proper inoculation where needed (fields without a history of soybeans), soil conditions that support nodulation, adequate phosphorus and potassium levels. While soybeans supply much of their own nitrogen, overall fertility still plays a role in achieving consistent yields.
Soybeans are commonly in rotation with corn and wheat, their rotational role can influence nitrogen availability for the following crop, residue levels and field conditions, pest and disease cycles. Soybeans are a low residue crop, which can help with field management and planting conditions for the next crop.
Successful soybean production depends on a multitude of factors:
- Achieving a uniform plant stand
- Managing weeds early in the season
- Monitoring for pests and diseases
- Maintaining good soil conditions for root development
- Managing harvest timing to reduce losses
Soybeans can be a flexible crop, but yield is still shaped by conditions early in the season and during flowering & pod development. Consistent stands, effective weed control, and favorable growing conditions all contribute to final yield.