Effects of seed advancement and sowing date on establishment, bolting and yield of sugarbeet

SUMMARY An advancing and devernalizing treatment for sugarbeet seed has been developed which, in England, allows sowing to be brought forward safely by c. 10 days to around 10 March. Experiments done each year from 1988 to 1991 were used to assess the value of this change. They showed that sugar yield increased by 0·048 t/ha/day because seed advancement resulted in more rapid emergence, and by 0·042 t/ha/day as a result of earlier sowing. As an average of all appropriate data from experiments in England since the 1950s, the advantage of sowing in March is 0·035 t/ha/day. However, the actual change in sowing date which the farmer might achieve will depend on soil type and rainfall. Daily rainfall and evaporation data for eastern England in March and April were used to predict the number and distribution of available machinery work days. On this basis, the average sowing date was predicted to advance by 9 days. Thus the sugar yield improvement which could be produced by advancing and devernalizing beet seed is equivalent to 9 days at 0·035 t/ha/day, plus 0·19 t/ha, or c. 0·5 t/ha. In practice, this should translate into an increase of 0·35 t/ha, or c. 5% of the average yield.