Own winter wheat variety mixtures – methods and experiences

Together with two organic farmers, the Innovation Centre for Organic Farming has tested two methods for making their own winter wheat mixtures.

By Karen Munk Hansen

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Variety mixtures are generally more robust in terms of disease and yield than single varieties, and if the varieties in a mixture have different growth habit, the mixture may also have better weed competition than the same varieties in pure stands.

There are ready-made mixtures of varieties on the market, but if you have specific requirements for the mixture, you can also mix it yourself. If you buy a ready-made mix from a retailer, the varieties have been evaluated for growing in a mix and the seed is delivered in one go. If you mix it yourself, you have more freedom, but you have to do the variety evaluation yourself and there may be several deliveries to keep track of.

Three varieties in the mix

In a demo trial at two organic farmers, mixtures of the varieties Pondus, Pacman and Fritop were sown in a 1:1:1 ratio. The varieties were chosen on the following basis:

Pondus is marketed for both conventional and organic cultivation and has performed well in terms of yield over the past five years in conventional trials. It has a 'flat' growth form, which potentially shuts out weeds in the autumn.
Pacman has given top yields in the variety trials in the National Trials® in recent years. It gives a very low additional yield for fungal control, indicating good resistance to the most common fungal diseases.
Fritop has a modest yield potential in pure stand, but it is taller than the other two varieties, which gives good weed competition, but also increased risk of lodging. It has a stalk, which makes it easy to recognise already at emergence.

The variety mix is sown with a 6 metre Väderstad Spirit seed drill in both locations. The plots are 30-36 metres wide.

The seed can be delivered to the field and the varieties are layered in the seed drill.

Mixing can also be done with a front bucket on the loading floor. This method gives a uniform mix.

Trial design

Demo trials at two locations
Two treatments: Seed mixed on barn floor and seed mixed by layering in seed box
Plots: four to six side-by-side tracks of each treatment with two replications at each site
Plant numbers and seeding depth as usual with trial hosts.

Two mixing methods tested in practice

The mixes were made in two different ways. Firstly, by mixing the varieties with a front loader on the barn floor, and secondly by placing the three varieties directly in the seed drill in layers and allowing the mixing to take place during sowing. The quality of the two methods was assessed in the crop in the field.

The first method is more labour-intensive and involves some transport when refilling the drill. The second can be done directly in the field, but the experience here is that the seed drill needs to travel about a hundred metres before a cone effect occurs in the seed box and the mixture of varieties is even.

Advantages and disadvantages of the methods

Both mixing methods work in practice with three varieties, except for the slightly uneven start-up when mixing in layers in the seed hopper. If you want to mix more varieties, floor mixing will probably give the best results in the field.
There are advantages and disadvantages to both methods, and the two trial hosts each prefer their own method.

Mixing on the floor	Mixing in seed drill
Extra workflow with floor mixing Transport when refilling Risk of spillage is higher Possible to mix a larger number of varieties	Easy to work with less risk of spillage Seed can be delivered to the field Mixture is only even after about 100 metres of driving Refilling should be done before the seed hopper is completely empty Seed rate on the seed drill should be adjusted after a few passes when the mixture has become even.

Mixing on the floor

Mixing in seed drill

Extra workflow with floor mixing

Transport when refilling

Risk of spillage is higher

Possible to mix a larger number of varieties

Easy to work with less risk of spillage

Seed can be delivered to the field

Mixture is only even after about 100 metres of driving

Refilling should be done before the seed hopper is completely empty

Seed rate on the seed drill should be adjusted after a few passes when the mixture has become even.

The Fritop variety has a stalk and is taller than the other varieties in the mix. Clear varietal differences make it easier to assess the quality of the mix in the field.

The grain in the first sowing pass with mixing directly in the seed box is slightly lighter in colour. The Fritop variety was at the bottom of the seed box and there is a preponderance of this variety until the air pressure mixing gets going properly.

National trials provide further knowledge

The variety mixtures performed very well in both demo trials. There was generally low incidence of fungal diseases in the demo trials and no differences were observed between the mixing methods. With the experimental design used, no final conclusions can be drawn about the health and weed competitiveness of the variety mixtures, but we expect a data basis for this in the National Trials 2025 and 2026, where different variety mixtures and single varieties are examined in terms of yield, weed competitiveness and disease susceptibility.

Memo: Experiences with mixing winter wheat varieties for own variety mixtures (pdf 15 pages)