You reap what you sow. That's a well-known saying. But attention during sowing and proper sowing technique do play an important role and are crucial for a successful start! Onion magazine asked 2 contractors about their experiences and tips and tricks for a successful sowing.
Kees Claassen - Crop consultant and planner contract work at Heyboer
We know from research and through experience that the sowing system is not all-important for onion cultivation, says cultivation consultant and planner of contract work Kees Claassen of Heyboer BV in Biddinghuizen. The biggest gains are to be made in preparing the land well and ensuring proper water management, he says. "If you take poor care of your land and have to deal with poor soil structure, this is much more decisive than the type of sowing system."
Claassen often sees the land being prepared too finely. "Last year, we have also seen again that the land becomes has more soil crusting earlier. With today's sowing machines, we can sow onions just fine if the sowing bed is a bit coarser."
Of all the onions we sow, 70 per cent are with an additive, says Claassen, for example with a starter fertiliser or insecticide granules. "In terms of sowing machines, we have different systems: 1.5-metre beds with five rows and 2.25-metre beds with eight rows. We also sow for organic growers. At a 4-row bed, we sow with double-steered GPS, so we can also hoe more accurately here. 75 cm rows on ridges is also possible, then it is 75 cm wide-couter."
Martijn Derikx of Derikx Akkerbouw Contractor in Ysselsteijn
Martijn Derikx of Derikx Akkerbouw from Ysselsteijn in Northern Limburg started contract work in onions about 10 years ago. The company is in a growth area as far as onion cultivation is concerned. In the beginning, the contracting company sowed at a few onion growers, now it sows about 500 ha of onions.
The contracting company sows with a 3-metre seeder directly behind the power harrow that loosens the soil slightly. We then sow on a nice moist surface, where the seed in the row is well pressed and lies in the moisture, says Derikx. Last year, an additional machine was purchased, which can also be used to lay drip hoses at the same time as sowing.
Determining the sowing depth is done by feel, looking at the soil conditions combined with weather conditions. In our region, we mostly sow on sandy soils, but sometimes also on heavy river clay, says Derikx. "On those, you have to deal with the conditions very differently again. On sandy soils, we prefer to sow a bit deeper (maximum 2.5-3 cm) in a dry spring, because these soils heat up faster and become drier."
In terms of sowing quantity, there has been a lot of experimentation in recent years, from three to over four units per ha. Derikx: "In my opinion, you have to start with enough plants and take into account that some may drop out. Also, we are in a scoop region in terms of earliness. We sow 4.1 units/ha with primed seed. This gives a nice even emergence, ensures enough plants and you are nice and early in terms of harvest time."
According to the contractor, there is more and more knowledge about the different varieties on offer. "In my view, there was sometimes too much focus on the maximum tonnes/ha and not always whether this variety is suitable for (especially) sandy soils. With better advice and new, better varieties for sandy soils, I see more and more room for the Hy-varieties in our region," Derikx concludes.
