FellowshipS Seminar 2016

Poster ABSTRACTS
Effect of row spacing and seed rate on the
growth and development of Winter oilseed
rape
Roisin Byrne 1,2 , Tom McCabe 1 and Dermot Forristal 2
1 School of Agriculture and Food Science, UCD, Belfield, Dublin 4
2 Crops, Environment and Land-Use Research Centre, Teagasc, Oak Park, Co. Carlow
Winter oilseed rape (Brassica napus) is the most widely grown oilseed crop in northern Europe. Oilseed rape is typically
sown at 125mm row spacing at seed rates of 50-80 seeds m -2 . Recent interest in low soil disturbance strip-tillage
for establishing oilseed rape has resulted in commercial growers seeding at 600mm row widths with relatively little
research available to support this practice. Experimental field trials to determine the impact of row width (125, 250, 500
or 750mm), seed rate (10, 15, 30 or 60 seeds m -2 respectively) and variety biomass type (standard and semi-dwarf) on
crop establishment, growth and yield were carried out over two growing seasons. These treatments were established
in conventionally cultivated plots in a factorial arrangement with four replications. Crop establishment was determined
post emergence, while biomass, leaf area, total green area and crop light interception were measured at regular
intervals during the season. The components of the crop at harvest were analysed and final yield values determined.
When sown at a wider (750mm) row width, poorer establishment was recorded at higher seed rates compared to
narrower row spacings. The wider row spacing’s also limited leaf area production with a 31% reduction in green area
index compared to 125mm row spacing at 60 seeds m -2 . However, the differences in emergence and overall biomass
development were not carried through to yield at harvest, as there was no significant difference between the treatments
(P=0.651). There was no significant effect of row width and variety type on yield (P=0.263). This suggests that there is a
limit to the impact of increasing canopy size on oilseed rape yield, allowing it to achieve a stable yield in a wide number
of sowing combinations.
35