That the dry weather would lead to a lower harvest in the Netherlands is no surprise. The harvest estimates of the CBS (Statistics Netherlands), however, exceed previous estimates. The harvest of consumption potatoes is 24 percent lower than in 2017, onions are expected to yield 44 percent less, according to the figures. “For onions it’s a proper crop failure,” says LTO-Akkerbouw chairperson Jaap van Wenum during the Dutch NOS Radio 1 news. The sector expected a 30 to 40 per cent lower onion harvest.

Onions
On average, the average yield is about 60 tonnes per hectare (in 2000: 62 tonnes; 2015: 57.4 tonnes; 2017: 55.7 tonnes). This contrasts sharply with the estimates for 2018, which amounted to 32 tonnes per hectare. The expected gross seed onion yield therefore amounts to 0.8 million tonnes, while this was historically high in 2017: 1.5 million tonnes. Throughout Northwestern Europe, the effects of the dry weather can be seen in the onion harvest. The UK expects a 40 per cent lower yield, Germany expects to harvest 35 percent less.

Potatoes
The average yields of potatoes are generally around 50 tonnes per hectare (in 2000: 53.1 tonnes; 2015: 46.4 tonnes; 2017: 52.8 tonnes). For this season, this means an expected yield of 3.1 million tonnes. That is 0.8 million tonnes less than the yield of 2017.

Normally, lower harvests translate into higher prices. onion growers might compensate for the bad harvest, but a lot of potato growers won’t be able to do so because they often work with supply contracts. That’s why Van Wenum thinks the potatoes won’t become much more expensive in shops, as opposed to the onions.

Yields per hectare: the difference between preliminary figures and definitive figures
Every year, the CBS provides the harvest estimates for the European agricultural accounts. The definitive figures will be announced late in January and often differ from the preliminary harvest figures. The definitive harvest estimates (gross yield) of 2018 will be published in January 2019 and is based on a survey among 5,000 farmers. based on this survey, the actual yield per hectare is determined, as is which part of the farmed land actually led to the yield (the harvested surface).

In 2010-2017, the definitive yield per hectare for consumption potatoes was lower than the preliminary (estimated) yield per hectare for three years. The biggest difference was in 2015, when the actual harvest was nearly nine per cent lower than initially estimated. In the other five years, the definitive yield per hectare was higher than initially estimated. In 2010, the yield was nearly three percent higher than estimated. During that same period for seed onions, the definitive yield per hectare was lower than the estimated yield for four years, and it was higher for four years. The difference varied from -6.5 percent (2014) to +7.4 percent (2011).

Harvested surface versus farmed surface
The harvested surface of consumption potatoes was lower than the farmed surface for four years during the past eight years. The biggest difference was in 2016 (three percent). For seed onions, the harvested surface was lower than the farmed surface for five of those eight years. The difference in seed onions was the biggest in 2016 as well (2.4 percent). During the other years, the harvested and farmed surfaces were the same for both crops.