The trial harvest figures from the end of July and the beginning of August show a very large variation in the results. This is mainly due to the leg data. The Fontane variety is lagging behind and still has a long way to go. It is striking that the early varieties achieve above-average yields, although the question remains how the late-planted plots will develop.
This is shown by the most recent trial harvest figures from the Belgian Viaverda (formerly PCA). The Belgian Trial Center for Potato and Vegetable Growing has published trial harvesting figures for various varieties. These show a large spread in yields, which is attributed to the different planting dates.
Large spread
On July 31, the early Amora variety was sampled for the third time on eight plots. On average, the gross yield is 47,9 tons per hectare, after an average of 92 growing days. The spread is large and varies from 30 to 66 tons per hectare. The difference between the plots planted in early April and mid-May remains clearly visible. The earliest planted plots average 60 tonnes per hectare (88% 50mm+) and later planted plots average 38 tonnes per hectare (72% 50mm+). Given that the plots planted later miss an average of 35 growing days, this large difference is not surprising.
The average yield of this season is above average compared to other years. The multi-year average is 92 tons after 35 growing days. If you only look at the planting dates, Viaverda expects an average yield of 42 tons based on other years. The first two plots had already been cleared and the maturity of the early planted plots was 75% to 80%. The plots planted later have a ripening rate of 34%.
Sinora above average
In addition to Amora, the early chip variety Sinora was also sampled on seven plots, by Viaverda, on July 31. The average gross yield is 34 tons per hectare after an average of 75 growing days. Compared to other years, this is also an above-average yield. Usually the first trial harvest takes place around 85 to 90 days and this averages out to 28 tons per hectare, a difference of 6 tons. Last year the yield averaged 24 tons per hectare after a comparable number of growing days.
Looking at the leg data, there is something to note. With the exception of one plot, everything was planted between May 11 and 20. The average yield from these plots even amounts to 38 tons per hectare. The plot that was dug up on June 12 has a yield of only 6 tons. That clearly drags the average down. Ripening on all plots is limited to a maximum of 20%.
Fontane has a long way to go
The Fontane variety shows a different picture at Viaverda compared to the early varieties. A total of 36 plots were sampled, spread across Belgian territory in Flanders and Wallonia. The planting dates are on average May 19, just a few days later than in 2023. The first potatoes went into the ground on April 18 and the last on June 17. In Walloon, due to persistent rainfall, planting took place last, with an average of June 1 as the planting date. In the plots planted later, there were hardly any potatoes of 50 mm+ to be found. In the previously planted plots, the percentage of 50 mm+ was 67%.
It is not surprising that the spread in yields is also large here. A yield of 4 to 68 tons per hectare was measured, with one plot not even requiring a trial harvest, given the small tubers. On average, the first trial harvest after 72 growing days amounts to 21 tonnes. An average of 2023 tons per hectare was also measured in 21, after an average of 75 growing days. Nevertheless, this yield was ultimately the highest since the last five years at Viaverda. The five-year average is 37 tons per hectare in the first week of August.
No comparison
The Belgian trading company Bruwier Potatoes also conducts trial harvests of the Fontane variety every year in week 31. The planting dates for their growers vary from May 5 to June 12, they announced on August 8. The average net yield (gross -15%) of the test harvests amounted to 24,1 tonnes, of which 35% was in 50 mm upwards. In the five previous years, the average yield was always above 30 tons per hectare, although no measurements were taken last year in week 31 due to the very late planting dates. That is why no comparison can now be made with that year. They also usually include the Challenger variety in the test harvests, but the planting dates are too late to show results yet.
Season continuation uncertain
Given the results from the test harvests and the comparison of the Fontane variety at Viaverda last year, the yield does not necessarily have to be low or below average. The early varieties that were planted on time also show a good yield on average according to the trial harvest figures. However, this is very different for the plots planted later. Last season we had very growing weather in July and August with sufficient moisture, which allowed us to grow many kilos. This is different with today's high temperatures and limited moisture. In addition, the crops are showing signs of signs earlier due to the root system, which is less well developed in this swampy year. Some regions have had some water, but the crop also needs a lot at this stage of growth.
Seed potato quality
In addition, Viaverda's trial harvest figures show high tuber formation, which is also seen in the Netherlands by a large proportion of growers this season. That requires more energy to get coarse potatoes and therefore the final kilos. Finally, water damage and poor seed potato quality (including late planting) should not be overlooked.
Viaverda also reports that there were attendance problems in the plots sampled. Plants are missing and there are losses in the field. However, additional percentages of the test grubs have been deducted from the sampled plots to compensate for this effect.