Biopolymer seed coatings to improve winter wheat establishment when broadcast into standing soybean
A biodegradable, hydrophilic biopolymer seed coating designed to improve germination and winter survival of winter wheat broadcast into standing soybeans. The coating accelerates water uptake and protects seeds from desiccation, enabling timely planting without waiting for soybean harvest and reducing yield losses of approximately 1 bu/ac per day from delayed sowing.
Overview
This solution addresses a critical agronomic challenge in Ontario's corn-soybean-wheat rotations: winter wheat is ideally planted in September or October, but soybean harvest often extends into November, forcing late plantings that cost farmers roughly 1 bushel per acre per day in lost yield. The proposed approach broadcasts winter wheat seed directly into standing soybeans at the R6.5 growth stage using agricultural drones or high-clearance spinner-spreaders, then applies a thin, biodegradable hydrophilic biopolymer coating to each seed. The coating speeds water uptake during germination and shields seeds from drying wind and sun at the soil surface, improving stand establishment and unlocking the agronomic and economic benefits of diversified crop rotations, including improved soil health, nutrient use efficiency, and reduced pest pressure.
Technical specifications
Core innovation: A water-based latex coating made from abundant natural macromolecules such as proteins and starches, with hydrophilicity and degradation timing tailored through grafting techniques.
Key features:
- Hydrophilic biopolymer layer that increases the rate of seed water imbibition and reduces seed desiccation on the soil surface
- Biodegradable formulation designed to break down after supporting germination
- Application via spraying or fluidized bed mixing for uniform coverage and adhesion
- Tunable polymer composition, layer thickness, and coating durability
- Compatible with drone-based or spinner-spreader broadcast seeding into standing soybean canopies
- Scalable to 100-plus acre operations using existing aerial application equipment
Development partners: Polymer chemistry and formulation led by Dr. Tiz Mekonen at the University of Waterloo; germination cabinet stress testing and field trials conducted at the University of Guelph using an XAG P-30 agricultural drone.
Technology readiness level
The project is at an early-to-mid stage of development. Prior two years of field work demonstrated that broadcast wheat into standing soybeans at the R6.5 stage is feasible and produced approximately 70 bu/ac, but stand establishment was inconsistent due to poor germination and seed desiccation. The current work program follows a staged validation path: five months of polymer development and formulation, one month of controlled germination cabinet stress tests, and eleven months of multi-date field trials comparing coated and uncoated broadcast wheat against drilled wheat planted after soybean harvest. Outcomes will quantify germination rates, winter survival, and yield across sowing dates and soybean growth stages to determine commercial readiness.
About University of Guelph
The University of Guelph is a comprehensive, mid-sized public research university in Guelph, Ontario. Industry partners engage through an on-campus research park and the Ontario Veterinary College’s teaching hospitals, which enable product evaluation and clinical translation. The university’s Arboretum and the nearby Agriculture and Agri-Food Canada Guelph Research and Development Centre offer living laboratories and federal linkages that support collaborative R&D. Research is backed by competitive federal funding and strong provincial support via the Ontario Agri‑Food Innovation Alliance. The Research Innovation Office serves as the university’s technology transfer and industry liaison hub, supporting IP, licensing, and co‑funded partnerships.
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