The effect of drilling date on the growth and yield of oil-seed rape (Brassica napus L.)

Abstract

SummaryThe effects of drilling date (18 August–22 September) on the growth and yield of oil-seed rape (Brassica napus) was studied in a series of five experiments over three seasons. Autumn and winter growth of the crop, as measured by dry weight of tops and leaf area, was severely reduced by delayed drilling, especially if it was later than 10 September. However, during the spring and early summer the differences in crop weight due to drilling date declined and in four of the five experiments there were no detectable differences in seed yield between early- and late-sown crops. The yield decline in the fifth trial was small. Measurements of components of yield showed that later-sown crops had fewer pods per plant and slightly smaller seeds but apparently more seeds per pod. The practical significance and reasons for the recovery of late drilled crops from early poorer growth are discussed.