2. Comparison against provisional estimates
Yields have generally been revised downwards since the release of initial estimates in early October. Yields for oilseed have been revised slightly upwards.
- Overall cereal production is estimated at 2.86 million tonnes; 226,000 tonnes or seven per cent below provisional estimates.
- The estimated increase in production of spring barley (up 11 per cent) is less than suggested by provisional estimates (16 per cent).
- Winter barley production rose by 23,000 instead of 42,000 tonnes.
- Wheat production was down four per cent rather than the increase of seven per cent initially estimated.
- Oats have seen an fall of eight per cent, rather than the similarly sized increase initially estimated.
- Oilseed production increased 41 per cent, rather than 38 per cent.
Overall, in the past the difference between provisional and final estimates has been typically around five per cent or lower. Chart 3 shows the differences in yields between the two estimates over the last ten years. Yield estimates of individual cereal crops do sometimes vary by more than five per cent.
This year the revision to overall cereal yield was higher than normal, at seven per cent. Discussions which produced the initial estimates occurred at the end of September, and were based on data from about 250 farms. While these farmers had been affected by the wet weather, they had nevertheless been able to find windows of a dry few days to get the harvest in. For many of them, yields had been exceptionally high, which led to the very positive initial estimates.
However, it seems that as the harvest continued it became increasingly difficult to find those windows of opportunity, and so much of the later crop was spoiled.
Barley estimates were five per cent out, but wheat production was considerably poorer than initially estimated, with a ten per cent difference. As frequently occurs due to the smaller numbers involved, the estimate for oats differed markedly, this year by 15 per cent.
Chart 3: Cereal Production, Comparison of Provisional v Final Estimates, 2008 to 2017
(below the line means final estimates lower than initial estimates)
Global supply of cereals is set to surpass 2.6 billion tonnes, according to the Food and Agriculture Organization of the UN  , with total supplies exceeding projected demand and stocks on the rise.