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Dirk Bakker (Van Iperen) and grower Dennis Grootscholten talk about biostimulants in radish cultivation

"Either chemical or organic: there is no middle road"

Is there still a place for small crops in the Netherlands with current legislation and regulations? Can you make it work with the limited amount of available chemicals and fertilizers? Take radishes, for example, which in the Netherlands have a total area of about 120 hectares. That's too small for manufacturers to invest a lot of money in the approval of the necessary resources. How do radish growers deal with this? We spoke to Dirk Bakker from Van Iperen and Dennis Grootscholten from Daily Fresh Radish in Naaldwijk, one of the largest players in the Netherlands.

300 million radishes
Together with his brother John, Dennis Grootscholten started with the cultivation of radishes in 1992, and last year they celebrated their 25th anniversary. "John did an internship at a radish grower at school. That's how it all started." Over the years, Daily Fresh Radish grew considerably. Every year about 300 million radishes travel to dozens of countries around the world. "We distinguish ourselves by always delivering a good product and by responding flexibly to the wishes of our customers when it comes to types and, for example, packaging."

Radish cultivation is a short-term crop. In the summer it lasts three weeks, while there are 10 weeks in the winter. And although radishes have relatively few diseases and pests, the number of approved products is very limited.

Dennis: "Some growers have tried to switch to organic in the past, but they didn't survive. To be completely bio and to also deliver top quality is simply impossible. We need an integrated approach, but there is no legislation that allows for that, let alone a certification. It is either chemical or completely organic. There is no middle road."

Downy mildew
Three years ago they did a trial to see if downy mildew could be biologically controlled. "We started with a small plot. Because things went well, we increased the surface time and time again until we even had a test area of one and a half hectares. That also went very well. At the end of the summer of 2016 we decided to do the entire garden this way. Unfortunately that only lasted two months: there was downy mildew everywhere! We didn't know exactly what the cause was. Either way, we had a very big problem."

Dirk: "Only one remedy for downy mildew is permitted in radish cultivation, and that can really only be used preventively. If you'd had a back-up solution at such a moment so you could intervene, the problem would have been much less great. Then as a grower you would also feel like experimenting more."

Grootscholten suffered considerable damage because of this, and the willingness to experiment with going organic again has gone away a lot.

Environmental certification
In the same period, the retail sector explicitly asked for an environmental label (On the way to PlanetProof). And the two brothers wanted to participate, but the question was whether it was feasible with radishes. The answer was 'no'. It turned out that the requirements for the use of plant protection products were based on the surface area of the nursery. Dirk: "Of course that is strange. The more crops per year, the fewer resources available per crop."

The Grootscholtens therefore refused to participate. "In the end, this led to them reversing the regulations and the amount of resources to be used is now allocated per product. That made it feasible for us, so we now have the certificate "On the way to PlanetProof."

Fertilizing
There are also rules about fertilizing. For example, the phosphate figure (PAI number) in the soil at Grootscholten was above the new standard. "That means that we are no longer allowed to administer phosphate. But with every bunch of radishes you do use up phosphate. Eventually you will end up with a shortage."

Dirk: "The Grootscholtens have paid a lot of attention to the soil here for a number of years. This means that a stock of phosphate has been built up. By applying four centimeters of high quality organic matter every year, that phosphate has not been rinsed out. The problem, however, is that the plant can't always absorb the phosphate that's present. That is why we now use a biostimulant to ensure that the plant can use the phosphate."

On the advice of Van Iperen, a biostimulant was chosen based on selected humic acids. It's now known that this makes the stored phosphate absorbable for the plant. Dennis: "By analyzing the tuber and leaf, we know that sufficient phosphate is being released. So far things are going well and we hardly see any differences in the values. We also keep a close eye on the amount of phosphate in the soil. At a given moment, the phosphate supply stored in the soil will fall below a critical value. Then we will review the phosphate fertilization again. Oddly enough, it's permitted to use organic phosphate, but we prefer to not do this as it brings other problems."

Small crops
Grootscholten is pleased with the attention that Van Iperen gives to the small crops and the support they receive. "It would not be all that bad if we were dealing with a level playing field. Take Germany. If there is a problem there, they can use the regional resources that are available for this. But here that's out of the question. As a grower, you're at a disadvantage right away."

Despite the limitations, both men do see a future for small crops in the Netherlands. "It forces us to be mainly preventive, in a systemic approach. We expect that the use of biostimulants will increase. If the plant becomes more vital, we can use plant protection products more selectively. However, it would be very helpful if things were more flexible. In an integrated system you should be allowed to intervene once in a while. This awareness must also sink in with authorities."

For more information:
Van Iperen
www.iperen.com
info@iperen.com

 

Daily Fresh Radish B.V.
www.dailyfreshradish.nl
info@dailyfreshradish.nl

 

 

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