Influence of no‐till furrow opener and seed treatment on ultra‐early wheat seeding systems

Abstract Ultra‐early planting is an alternative practice that involves planting based on soil temperature, initiated once the trigger temperature of >0°C is observed, regardless of calendar date. Our previous research concluded that spring wheat ( Triticum aestivum L.) grain yields are maintained or improved with enhanced yield stability when adopting this practice. However, a knowledge gap remains around the influence of furrow opener configuration and seed treatments to mitigate abiotic stressors related to cold soil and ambient temperatures. Thus, a 5‐year experiment was conducted in Lethbridge, AB, to examine the effects of planting dates triggered by soil temperatures of 0°C, 2.5°C, 5°C, 7.5°C, and 10°C; seed treatment (tebuconazole, prothioconazole, metalaxyl, and imidacloprid vs. untreated); and furrow opener (knife vs. disc) on ultra‐early planted spring wheat. Optimal grain yield was achieved when wheat was planted at a soil temperature of 0°C, irrespective of seed treatment and furrow opener type. A significant yield reduction was observed when wheat was planted at a soil temperature of 10°C. Wheat planted at soil temperatures of ≤7.5°C with a disc opener often resulted in high and stable yields, regardless of seed treatment. Grain protein concentration responses to soil temperature trigger were less consistent, but wheat planted at 10°C accumulated low and unstable concentrations. Seed treatment delayed emergence, flowering, and maturity; reduced head density; and ultimately lowered grain yield. Overall, spring wheat grain yield and protein concentration were optimized when planted at soil temperatures of ≥0 and ≤7.5°C using a disc opener, regardless of seed treatment adoption.