Precipitation pulls main crop to average

In the most recent figures – for week 35 – is coming Aviko Potato for all varieties at more than 55 tons per hectare gross. This means that the growth has been almost 5 tonnes in one week. Only in 2017 and 2019 was the yield (significantly) higher. Given the trend, growth will level off after next week, working towards an end.

Coarse and high OWG
The underwater weight has remained stable since the rainy period. At 390 grams in the 40 millimeters upwards, it is relatively high for this time of year. An image that has been visible for several weeks. What is also characteristic of this season is how large the potatoes are. More than 85% have already reached the size 50 millimeters upwards. That level is the same as 2017. Especially in a variety like Innovator, this is due to a smaller number as a result of the dry spring.

Compared to Belgian potato crops, Dutch plots are in better condition on average. With our southern neighbors, the Innovator yield in particular is still well below the multi-year yield average. There was also less precipitation there during August compared to the Netherlands. This also applies to France and Belgium.

Fontane withstands heat well
At the end of August, Fiwap, Carah, PCA and Inagro again sampled 31 Fontane plots and 18 Challenger plots in Belgium. After an average of 129 growing days, Fontane's net yield is 42 tons per hectare. This is 1 ton above the 5-year average and 2 ton above last year's result. Challenger reaches 38 tons after 127 growing days. This is 3 tons below the 5-year average.

The difference between Flanders and Wallonia is large in terms of yield, which is partly caused by irrigation. The yield in Flanders is higher for both varieties, although for Challenger it is only 1 tonne. For Fontane the difference is 6 tons. Just like in the Netherlands, the Fontane parties are already quite coarse at 80%. At Challenger this is much less at 63%. The underwater weight is high, at over 400. Especially in the Challengers.

Regrowth after rain
If we look at the graphs, the growth curve is now above the average for this time of year. In most years, except 2017, growth has now started to level off with a small increase in the September weeks. The crops have clearly benefited from rainfall and especially moderate temperatures and resumed their growth. As a result, the OWG has decreased. Significant hedge growth is noticeable in a single Fontane plot. The foliage has now died for 40% of the Fontane variety and for a third it is already 50% or more. The heat wave has clearly accelerated aging.

At Challenger the picture is variable, with a spread of 20% to 80%. On average that is 44%. An almost equal percentage also fails to meet his grossness. The variety has clearly not benefited sufficiently from the rainfall, as Fontane did. The expectation is that the variety will end the season below average, but better than in 2018.

Large precipitation differences
After a record-long heat wave, many Dutch areas have been treated to a lot of precipitation, with enormous regional differences. For example, this shows a detailed map of Flevoland, which varies from 70 millimeters to almost 230 millimeters. Little rain fell during the month, especially in the southeast and east. In addition to Flevoland, a fair amount of rain has also fallen in the southwest, west and north, so the potatoes do not lack moisture for the last weeks of growth.

Weeronline – which was taken over by Weerplaza this month and is a partner of Boerenbusiness Agricultural weather – recently published a forecast for the weather this autumn. For September, meteorologists expect a dry and cool month with occasional showers. The weather models now indicate a lot of precipitation, especially in October and November. The comparison with last autumn is made here. Drier and colder weather is expected towards winter.

Precipitation or lots of sun?
However, the weather institute is keeping an eye on things. There are also weather models that predict a very dry and sunny October, after which November in particular will be very wet. After a mild September, expectations quickly become uncertain.