Preliminary data shows that sugar beet can increase yield during campaign by between 30 and 45%. Data indicates that the extent of the yield increase is partially determined by variety although there may be an interaction between variety with soil type. The implication that some varieties may be more suited to early and later harvest has significant commercial implications. This trial will test this hypothesis and indicate how BBRO can give guideline on choice of variety in relation to harvest date. Additionally, our understanding on how the canopy growth characteristics of different varieties are related to yield performance at different harvest dates would allow to us assess new varieties in RL trial on their harvest date suitability at an early stage without extensive multi-site/annual testing.
Preliminary trials in 2017 and 2018 have identified difference between varieties. In 2017, the range of yield increase between varieties on BBRO Demo Farm varieties strips was recorded as 35-46% between September and December. Limited canopy assessments indicated that varieties with more upright canopies, better canopy ground cover (%) and fewer senescing older leaves increased yield more in the period tested. These yield estimates were based on replicates digs along each variety strips, but variety strips were not replicated. This was an average across three sites and site differences were apparent.
In 2018, the severe drought affected canopy growth substantially in plots designed to gather some more pre-liminary data both at the BBRO Bracebridge site and on BBRO Demo farms. At Bracebridge, over 50% of the canopy was lost due to drought stress. The Lincolnshire brash soil type was relatively thin and very free-draining. Following rain in September, extensive canopy re-growth occurred, and few differences were recorded between varieties in their canopy re-growth characteristics. Whilst yields increased substantially in the autumn 33% (Bracebridge) there were no consistent differences between varieties. Across the Demo farm strips in 2018, the range of yield increase was considerably greater (12-52%) as was the range of canopy development in the autumn. This largely reflected the range of soil types. The results indicated that in general, yield increases were greater at sites recovering from drought stress and where lots of canopy re-growth occurred compared to sites where there was little re-growth. Differences were recorded between varieties at each site, but these were not consistent across the different sites. The response of a variety to stress at this stage of the season maybe an important determinant of it’s potential to subsequently increase yield.
Outcomes / Key Message For Growers And Industry
- Previous trial work has shown differences between varieties and their yield at different harvest dates.
- Earlier work has indicated that this may be related to their canopy growth characteristics with upright canopies associated with greater yield progression at later harvest dates than varieties with more prostrate growth habits.
- The replicated trial in 2018/19 highlighted the differences between the growth habit of varieties but showed that this was not related to yield progression although the levels of yield increases was lower than average due to the drought conditions.
- Variety demonstration plots on an adjacent site but more severely droughted soil type, showed that differences between varieties was related to the extent of canopy recovery after drought stress and this was a linked to yield progression.
- The relationship between varieties, their growth habits was possibly masked in 2018 and the effect of the drought on variety yield progression was more important.