'Onion cultivation offers food for thought'

At the end of a new onion growing season, Syngenta onion expert Kees Jacobs is looking back and forth. Some storage facilities are concerned about the 2021 harvest. And cultivation will not get any easier in 2022. But Kees traditionally ends positively and constructively.

With the first half of the storage and marketing season behind us, there is little reason for the growers of yellow seed onions to rejoice. And that is not only due to the pricing, says Syngenta onion expert Kees Jacobs. "Some growers have problems with storage with thick necks and water skins. The thick necks arose because many plots had a thin position. This had several causes. The onions were on the road for a long time due to the cold spring. And there is hail on a relatively large number of plots. - or there has been dust damage, resulting in plant loss. Due to the thinner position, you get large, looser onions. And such a batch contains a relatively large amount of moisture."

Thin position gives more thick necks
If an onion can grow solitary or with a lot of space, it becomes a colossal plant that remains vegetative for a long time and starts to bulb late. Large loose onions and a greater chance of thick necks (bolts) are the result. Such a batch is more sensitive to diseases and more difficult to store because of the high amount of moisture. A regular and not too thin stand is therefore crucial for good quality onion.

water sheets
The end of the growing season also had a surprise in store that deteriorated the storability of batches: water sheets. "That can be traced back to too rapid dieback", Jacobs knows. "You saw that many fields died at an accelerated rate in August. Not only because of the downy mildew, but also without a directly identifiable cause. The natural gradual drying process was disrupted and the neck closed before the onion was really dry. The chimney for the drainage of moisture was too high. close soon." Water skins are more likely to occur in skin-resistant breeds because they have more difficulty with the drainage of moisture. Lots with a lot of moisture due to thick necks and/or water skins require more attention in storage, but with the right approach problems remain manageable, according to the onion expert: "You should not only continue heating for longer after storage, but also return more often with drying actions. If the RH of a batch exceeds 80%, I recommend that you simply start firing again." Jacobs is a strong supporter of the use of an electronic RH meter in onion storage.

He also has a practical storage tip for the coming period: "Put out about fifty onions regularly in moist potting compost at room temperature and cut them through after about two weeks. When you see roots and a sprout appear, you know that the MH has worn off and that the time of delivery is approaching."

Priming grows
Looking ahead to the new season, Jacobs notes that the advance of primed seed is not over yet. "Last year we went from 20% to 40% and this year that will increase to about 50%, I expect. Growers must bear in mind that they must be able to irrigate, because a primed seed must be able to go through in one go. "Irrigation does fit into your job picture. Don't forget that irrigation has become considerably more expensive due to the increased diesel prices. But that does not alter the fact that priming offers many advantages due to the more homogeneous crop status."

Jacobs is less enthusiastic about another trend and that is non-inversion tillage (NKG). "Don't get me wrong", says Jacobs, "I have nothing against the system in principle, but I just find it less suitable for fine-seeded crops. Especially on the somewhat heavier soils, all kinds of extra treatments are sometimes necessary with NKG to incorporate an overwintered green manure. and to get a nice seed bed. All those extra working passes give more chance of compaction and an onion is sensitive to that."

Cultivation is becoming more challenging
For the 2022 cultivation season, the Syngenta advisor sees a number of significant challenges that have already received a lot of attention in the trade journals and winter lectures. Jacobs: "Weed control is becoming more difficult; we have lost quite a few herbicides in recent years. And with disease control, the approach is not only more difficult but also more expensive. We have lost Mancozeb and all the resources that it contained. The schedules that are possible with the remaining resources are more expensive. And in difficult periods it will be quite a struggle to get the schedules around. We will need everything."

Risk perception greater
All in all, the risk perception of onion cultivation will have increased among many arable farmers. Because in addition to potential complications in storage and the greater challenges in weed control and disease control, there are known risks related to emergence, insect problems and the timing of MH spraying. Cutting back on cultivation measures is not the way to deal with this, says Jacobs. "Of course, it is an expensive crop and you always have to keep counting your cost price. But cutting back on fertilization and crop protection tends to have the opposite effect. It soon comes at the expense of yield or quality. But you can minimize the risks as much as possible. Choose the better plots for onion cultivation. It is an expensive crop that does not lead to a good result on every plot. Leveling, drainage and water availability must be in perfect order. And choose the right variety. I sometimes see varieties that falling bare quickly on light plots. That is asking for problems. And also adapt your variety to your storage purpose. If you are going for longer storage, then choose a hard and skin-resistant variety with a high storage yield. sell, choose a banger as our Promotion."

Jacobs advises growers not to make ad hoc decisions about whether or not to sow in response to the 2021 season. "Aim for continuity in your company and in your onion cultivation. Don't settle the crop on one less good season, but look at it over several years Because every year, in all the risks and challenges, there is also an opportunity for the professional onion grower!"

Do you want to know how best to manage the risks of your onion cultivation? Watch the video below: