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More can be achieved on shore with resilient onions
"With resilient onions you can get more kilos off shore. Measures that strengthen resilience are therefore quickly worth implementing." This is what Jan Koelmans of George Pars Graanhandel in Sint Jacobiparochie (Friesland) says.
He sees that growers are increasingly recognizing the importance of a stable growing, resilient crop. "There is now much more attention for targeted fertilization than before. And products that make plants more resistant to diseases and pests and stimulate or support growth can now also count on serious interest," says the advisor. An important 'crop booster ' with which good results were achieved last season Serenade. "This product has the potential to develop into a beautiful, green link in onion cultivation."
"No, it will probably not be a great year for onions anymore. There has simply been too much water in most places." Jan Koelmans says it with some caution, because he also knows plenty of plots where the onions are doing quite well now (mid-June). "The differences here in the North are simply great. We have plots with only a few percent loss, but also plots that have been thinned out by half due to heavy showers. And what will happen if we have a few weeks of drought in the summer? onion roots are high in the ground, because they haven't had to look for water yet. We may need the reels again soon."
Change in thinking
Koelmans' words are indicative of the bizarre spring in which the onions have had a hard time so far. Due to the soaking wet weather, fungal diseases - and especially downy mildew - are once again lurking. The advisor recalls the 2021 season, when the disease spread considerably. "Then, after a number of dry summers, we were woken up again and we knew again how quickly the fungus can rage through the crop and how extensive the damage can be. The realization also emerged that with the disappearance of mancozeb -containing products, the problems with downy mildew could become much greater in the 2022 season. There will then be no option to resort to the disease."
According to Koelmans, this intense mold year has caused a major change in thinking. "Where we previously relied almost entirely on chemical disease control, we have worked hard in recent years to make cultivation more resilient. For example, more attention is now paid to fertilization, such as dividing the NPK dose into three or four parts instead of one part before and one part after sowing. We are now also looking more at the need for trace elements such as calcium, sulfur and manganese, although it remains a quest to provide these nutrients effectively and at exactly the right time. In any case, the focus is now more on a stable growing and resilient crop in which diseases and pests have less chance."
Focus on Serenade
For this reason, biological fungicides have also become increasingly popular. As far as Koelmans is concerned, the drug is Serenade - based on the bacterial strain Bacillus amyloliquefaciens QST 713 - currently the main representative within this segment. "We know from Serenade that it has been seriously researched for years in many different crops and that the results are not made better than they are. That gives us confidence to use it on the farm in a down-to-earth and realistic way," says the advisor.
In recent years, experience has mainly been gained in seed potatoes, where the product is used to improve peel quality. "Good results have been achieved, especially with scab-sensitive varieties, with visibly less scab."
Although the results over the years may be somewhat erratic, Koelmans knows that there is now a permanent group of growers who work with it every year. Last season, Serenade was also used on a trial basis on two onion plots in Pingjum (variety: Red Tide). The results were downright good. In the section where Serenade was applied, the yield was no less than 10% higher (nationally: 4%). In addition, the net weight (taring) was also slightly better. Koelmans emphasizes that although these results give a good indication of the effect of Serenade in onions, more tests are needed over several years and on several grounds for 'harder figures'. For that reason, this year there will be further trials with Serenade among onion growers in Oldambt, Groningen.
Green link in onion cultivation
Koelmans does not yet dare to say whether Serenade will take off in onion cultivation in the coming years. "Growers in our work area are fairly down-to-earth and do not immediately change their minds after a presentation with good test results. It is mainly: first see, then believe. Moreover, we have many rich soils here where onions can grow well. So Serenade will really add something extra. have to offer,” he says. Nevertheless, the advisor notices that growers are becoming more curious about organic products such as Serenade and that some are also willing to experiment with it.
"If it turns out in the coming years that crops with Serenade grow better and become resistant to diseases and pests, then enthusiasm for the product will certainly grow. And if it turns out that - especially in years with difficult growing conditions - you can also gain even more kilos with it on shore, then things will start to move even further. Especially on that point, I see potential for Serenade: measures that give just a little more return on an expensive crop such as onions are quickly worth implementing Serenade could well grow into a beautiful, green link in onion cultivation."
