Optimization of plant spacing and fertilizer dose for high-yielding mustard varieties

Abstract:

Here is a paradox in canola-type mustard agronomy: breeders keep releasing varieties with higher yield potential, but average on-farm yields in the Maritime provinces haven’t budged in a decade. The disconnect often traces back to planting density and fertiliser calibration that still target older, shorter-statured cultivars. This research optimised plant spacing and fertiliser dose for two high-yielding Brassica juncea varieties (AAC Condor, AAC Summit) at Truro, Nova Scotia, and Guelph, Ontario, during 2023. Five spacings (30×10, 30×15, 30×20, 45×15, 45×20 cm) and three fertiliser rates (80%, 100%, 120% of recommended dose) were arranged in a factorial split-plot design. Seed yield peaked at 30×15 cm with 120% RDF (2.04 t ha⁻¹ for AAC Condor at Truro), 21.3% above the widest spacing at base fertiliser. The spacing–fertiliser interaction was significant (p = 0.003) for yield but not for oil content. AAC Condor outyielded AAC Summit by 6–8% at all combinations. These data support narrowing row spacing to 30 cm and raising the fertiliser rate by 20% as a practical package for new-generation mustard in eastern Canada.