An earlier than usual harvest of organic potatoes started nationwide two weeks ago. The fields in the new potato areas,
ting took place much earlier than in the classic cultivation regions. There were slight quality problems through wireworm infestations. Some farmers have therefore had to clear their organic potatoes for quality assurance in a warehouse - for new potato growers this was an unusual measure.
After the unusual drought in Northern Europe, farmers could only resort to intensive irrigation in order to maintain yield and quality. Facilities without the option to irrigate have had to accept significant yield losses.
Some surfaces even saw a total failure. Even in very good locations, where the soil holds the water for a longer time, there is no more soil moisture, since in many regions it has hardly rained at all for 18 weeks. In addition, there were very high temperatures and there was much wind, which dries out the soil. This combination has not happened like this very often before.
For regular growth, a potato stock needs about 450-500mm of moisture over the entire growing season (source: Wilfried Dreyer Naturland Potato Consulting), which is available through soil moisture, morning dew and rain. Due to the lack of rainfall and the extreme heat over several weeks, since April 2018 in large parts of Germany there was a negative water balance of more than 400mm.
This deficit could only be compensated for conditionally through intensive irrigation. In past dry years, the fields were watered 3-4 times. This year there were up to 10 passes. This large effort, combined with good deep soil structures through sustainable farming in organic farming, could secure the yield of most farms. Nevertheless, there were always light scabs on the peels and holes from wireworm. Starting at temperatures of 25°C, potato plants experience growth stress. Since it was already very warm in May, many varieties have grown significantly fewer tubers than usual.
The soil must not dry out, because otherwise too much oxygen can penetrate, leading to scabs on the peel. Most common varieties tend to grow or "pupate" when dry. In the variety trials of the Chambers of Agriculture, almost all varieties responded to the high temperatures and the lack of water due by creating growth defects.
Most producers had to decide where to use the existing irrigation capacity, as the intervals have had to be significantly shorter. So growers who focused on their potatoes had to let their other crops largely dry up. In many places, the corn is already being chopped, so that nothing remains except for the straw.
In summary; from what we know at the moment, a somewhat below average yield is expected. In view of the extreme growing conditions and the resulting optical deficits, net amounts will be smaller than in previous years.
For more information:
Dr. Heiko Dreyer
Mobil: 0174 64 24 154
Gross Breese 3
Mobil: 0160 78 30