Agronomic Response of Winter Rapeseed to Rate and Date of Seeding
- Mary K. Moore and
- Stephen O. Guy
In northern Idaho, winter rapeseed (Brassica napus L.) usually is seeded on summer fallow in early to mid-August at 4.5 to 13.5 kg seed ha−1. A 2-yr study was conducted at Moscow, ID, to quantify crop performance as influenced by date of seeding and seeding rate. In the 1991–1992 and 1992–1993 growing seasons, high-erucic-acid winter rapeseed cultivars, ‘Dwarf Essex’ and ‘Bridger’, were seeded on four dates at 2-wk intervals from early August to mid-September at four seeding rates from 0.9 to 2.7 × 106 seeds ha−1. Greatest yield for the four dates ranged from 1974 to 2675 kg ha−1. Optimum spring plant stands for attaining those yields were between 61 and 112 plants m−2, obtained at different seeding rates, depending on the date of seeding. The lowest seeding rates (0.9 and 1.5 × 106 seeds ha−1) produced optimum spring plant stands for the mid-August and early September seeding. Higher seeding rates in early August and mid-September were necessary to achieve optimum spring plant stands.
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