Trial harvesting shows a significant backlog of potatoes

The second test harvesting data from PCA and Fiwap (31 Fontane plots and 18 Challenger plots) shows that the potato crops have only been able to grow slightly in the last 2 weeks. It ensures that the yield falls further below the multi-year average. Also in the Netherlands (new figures from Aviko) the gap with the 5-year average is increasing and the underwater weight is increasing further.

Fontane: growth very limited
The second trial harvesting of the Fontane plots in Belgium was carried out on Monday, August 10, when the plots had reached 116 growing days. The results show a total yield of 37 tons per hectare, with 5 plots not even yielding more than 25 to 30 tons per hectare. There are also 7 plots that have achieved a yield above 40 tons. All in all, however, the yield is well below the multi-year average of 41 tons per hectare (after 116 growing days).

The test harvesting data also shows that growth in the crops is limited. After all, the total revenue is the past 2 weeks only increased by 3,8 tons per hectare. While the multi-year average amounts to a daily growth of 400 kilos per hectare, this figure now remains at 280 kilos per hectare per day.

Due to drought, the underwater weight has increased significantly to an average of 433 grams, but there are even visible peaks of up to 476 grams. In addition, the difficult growing conditions mean that some deformed tubers are found on some plots. So far, throughwash has hardly been found. However, the plots are already starting to show ripening (leaf drop and/or yellowing of lower leaves): approximately 25% of the plots now show 30% to 50% ripening. However, with an average of 20%, the line does not yet deviate from a 'normal growing season'. However, it remains to be seen what effect the heat wave will have on this percentage.

Challenger: sorting remains better
The plots with Challenger had completed 113 growing days during the second trial harvest. This shows that the yield fluctuates between 24 and 41 tons per hectare, with an average of 34 tons per hectare. It is clear that this is well below average, because after 113 growing days it is 43 tons per hectare. In the Challenger variety, growth between the two test harvests was also very limited: 3,9 tonnes per hectare (280 kilos per hectare, per day).

It is striking that only 18 tons per hectare belongs to the sorting 50 millimeters upwards: 37%. This means that the sorting remains a lot finer compared to Fontane's, where this percentage is 73%. Usually around 19 tons per hectare are placed in the coarse grading around August 32. Challenger is currently forming a lot more tubers per bush. The underwater weight is currently 446 grams, with a range of 413 to no less than 478 grams.

Last trial harvest of Sinora
The last trial grubbing of plots with the Sinora variety was carried out on Wednesday, August 12. At that time, the plots had completed 114 growing days. The total yield during the last trial harvesting amounted to 41 tons per hectare, with a range of 36 to 52 tons per hectare. This is barely more than at the beginning of August, which means that growth has been limited. The underwater weight averages 387 grams. The figures clearly show that the plot that was irrigated most often achieved the best results: the highest yield (52 tons) and the lowest underwater weight (354 grams).

But in general, this variety has recorded a yield that is very similar to the multi-year average and the size can also be described as normal (78% in coarse grading). This semi-early variety was therefore able to make grateful use of the temporarily changeable conditions in the month of July.

Aviko also shows a deficit
In the Netherlands too, a considerable gap is visible compared to the multi-year average. From the latest trial harvest figures Aviko shows that the average yield per hectare has dropped further to 46 tons per hectare. The 5-year average is 47,6 tons per hectare. In addition, the average underwater weight at the start of the heat wave increased to 387 grams and the percentage of 50% millimeters increased to 81%. This is slightly below the 2017 level.

All in all, the potato harvest in the Netherlands, Belgium and... North France this season compared to the year 2016. It is clear that it will not be a great event, looking at the high underwater weights. An early ripening is therefore lurking. And in the above test harvesting data, the consequences of last week's heat wave are not even visible. It remains to be seen to what extent the backlog has increased as a result.