Ap. Everaarts et Cp. Demoel, THE EFFECT OF PLANTING DATE AND PLANT-DENSITY ON YIELD AND GRADING OFBRUSSELS-SPROUTS, Journal of horticultural science & biotechnology, 73(4), 1998, pp. 549-554
During three seasons the effects of planting date and plant density, a
nd their interaction, on marketable yield and grading of Brussels spro
uts (Brassica oleracea var. gemmifera) were studied in field experimen
ts. The marketable yield, as an average of three or four successive me
chanical harvests, decreased with delay in planting from the end of Ap
ril-early May to the end of June-early July. Final marketable yield le
vels varied between 29.4 tonnes per hectare when planting was early, t
o 17.4 tonnes per hectare when planting was late in the season. A decr
ease in yield with an increase in plant density from 2.7 to 4.4 plants
per m(2) was found in only one year. Grading (percentage of buds >31m
m) was not consistently influenced by planting date, but increasing th
e plant density increased the proportion of small buds. There were no
or interactions of only limited importance between the effects of plan
ting date and plant density on yield and grading, indicating that, wit
hin one year, for the whole range of planting dates the effects of den
sity on yield and grading are similar. For a high yield of small buds,
plant density should be increased and the harvest date delayed. For h
arvest planning, better use should be made of variation in maturation
time between cultivars, rather than of variation in the date of planti
ng. Maturation time within a cultivar can be manipulated by varying th
e plant density.