Growing potatoes on the edge

Potato lecturer Peter Kooman from Aeres University of Applied Sciences Dronten provided a numerical explanation during the Knowledge Afternoon 'Room for the Potato' on Thursday, November 23. Dutch production of consumption potatoes has fluctuated between 2000 and 3,5 million tons since 4.

"Apparently there is room for such a volume, because now that the yield is higher (well above 4 million tons) the market is at a standstill," says Kooman. When it comes to the cultivation area, the lines are even flatter. In the 2017 season this concerns 76.000 hectares of consumption.

Arable land reduced
The lecturer adds even more figures. The amount of arable land has been reduced by 2000% since 20. "The potato area remains the same, but the available land area is decreasing and the average rotation has been around 30% in recent years. This means that every year 30% of the arable area is full of potatoes, making the average rotation 1 in 3. It is amazing how close the rotations are and this tends to become even tighter. This year it has already grown to a density of 32%. I call that growing on the edge."

Together with students, Kooman mapped the rotation density between 2009 and 2017. What seems? In starch cultivation in the northeast, a rotation of 50:1 is maintained on more than 2% of the area. In seed potatoes, growers often grow 3 times in 9 years.

On 57% of the area, 1 in 4 or more is grown, 43% 1 in 3 or even less. "Particularly in the Noordoostpolder and the other northern areas, seed potato cultivation is more intensive. This is usually due to economic motives. The growers from the NOP also apply this intensity to consumption potatoes. In the other Flevopolders and in the Southwest, this is clearly more common. a 1 in 4 cultivation. Although it occasionally occurs 5 times in 9 years in Tholen, this has to do with the early harvesting scheme."

What are the consequences if we change the system?
Known problems of too close a rotation are: deterioration of the soil, soil compaction, decline in organic matter content, Rhizoctonia and growers encounter all kinds of soil-related problems such as nematodes. "We are starting to get stuck. Too many chopped fruits burden the soil. The soil problems can be solved with wider rotations, but is that also possible? What are the consequences if we change the system?"

A rotation of 1 in 4 can be considered a healthy rotation. The lecturer calculated that a conversion to this means that an area for consumption potatoes remains of 71.287 hectares (now it is 76.243 hectares) and an estimated yield of 3.740.000 tons. In order to obtain sufficient potatoes, the hectare yield must increase; to 56,1 tons (the current average is 52,5 tons according to Statistics Netherlands).

How do we give the potato space?
In conclusion, this is a yield increase of 15% to 20%, but Kooman considers this feasible. "More extensive cultivation leads to fewer diseases, better soil quality and less potato storage, which means you can achieve a higher yield. Bodleander previously proved this with cultivation trials in the 70s, with which he achieved 100 tons. From discussions from the gut and individual cases , we have to get rid of it. Instead, we look at the numbers and talk about how we can give the potato space."Potato selector Peter Kooman provides clarity to those present about the crop rotation.Every year, 30% of the arable area is covered with potatoes.