As sowing season approaches, one question tops the calls we receive: how many kilograms per decare? The question looks simple, but the answer arrives as three different numbers from three different places. The variety’s data sheet gives a range; for our barley varieties, 25-30 kg per decare under rainfed conditions and 22-25 kg under irrigation. The state uses 23 kg per decare as the basis when calculating seed subsidies. Growers, by habit and often without any calculation, sow 30 kg. None of the three numbers is wrong; each tells a different story. The data-sheet range is what the variety genuinely needs in the field, 23 kg is the basis of the subsidy calculation, and 30 kg is the preference that seed should not run short. Our advice is to stay within the data-sheet range and to choose its lower or upper end according to the field’s water. The table below shows these ranges side by side for five of our varieties.
| Variety | Rainfed | Irrigated |
|---|---|---|
| Ramata (six-row barley) | 25-30 kg/da | 22-25 kg/da |
| Manava (two-row barley) | 25-30 kg/da | 22-25 kg/da |
| Sinanbey (two-row barley) | 25-30 kg/da | Not recommended under irrigation |
| Renan (bread wheat) | 22-25 kg/da | |
| Tigre (bread wheat) | 22-25 kg/da | |
The difference between kilograms and plant numbers
The table speaks in kilograms, and there is a reason for that. In maize or sunflower the seed rate is worked out from the number of plants per square metre; because those crops produce a single stem, the number of seeds sown gives the number of plants, and of cobs or heads, obtained. In barley and wheat that arithmetic does not hold. A barley seed does not stay a single stem; in spring it tillers, sending up new stems from its base, and a single seed turns into several ears. How many tillers it produces varies from variety to variety. An attempt to give plants per square metre produces a range so wide, from 300 to 650, that it guides nobody in practice. Kilograms are the only measure that can be weighed in the field and set on the drill, which is why data sheets are written in kilograms.
There is one more allowance hidden inside the data-sheet range. Not all the seed sown becomes a plant. The analysis certificate of certified seed shows a germination rate of 97-98 percent, and in barley seed this rate never falls below 85 percent under any circumstances. In the field, unlike the laboratory, a further 5 to 10 percent is lost. The soil does not give every seed the same moisture, birds and insects take some, some seeds have lower vigour than others and, above all, deep sowing makes the seed exhaust its reserves before it reaches the surface. Why sowing depth should be 3-5 cm is explained in detail in our article on when to sow winter barley. The important point here is that this loss is already included in the data-sheet range. There is no need to add a further allowance on top.
The price extra seed pays in the field
What we see in the field is different. Thirty kilograms per decare is common practice, and so is keeping the drill setting a little wider. Behind this lies an understandable concern: if seed runs short, the field stays bare. Yet extra seed has a cost in the field, and that cost is usually invisible. As the stand thickens, every plant has to share water, light and soil nutrients with its neighbour. As competition rises, nutrients run short, stems thin out and ears come out weak. A dense canopy does not ventilate, so disease takes hold more easily. The result is more seed spent for less crop.
We have also seen the opposite. A grower who sowed 20 kg on a field where we recommended 25 kg even came out more profitable when the crop was well managed; the plants tillered freely and the ears were large. This does not mean, of course, that less seed should be sown. What we mean is that staying within the data-sheet range and not going to its upper limit unless necessary is enough on most fields.
The same logic applies to late sowing. When the sowing calendar slips there is a widespread tendency to add seed; we do not. What late sowing loses is the plant’s time to root before winter, and that cannot be bought back with seed numbers. Extra seed only brings the competition described above. When sowing is late, what needs reviewing is the variety and the date, not the rate.
Deciding by the field: dryland, irrigated and sowing method
One of the main reasons the data sheet gives two figures, for rainfed and irrigated conditions, is water. On dryland the soil moisture depends on rainfall and not every seed may find the water it needs to germinate. To cover that uncertainty a little more seed is sown on dryland, and that is where the upper end of the range comes from. Under irrigation germination is close to guaranteed, seed is sown at the normal rate and the lower end of the range is enough. For Sinanbey, selected for fully dryland fields, we give no irrigated figure because we do not recommend the variety under irrigation.
Method matters as much as rate. In our regions the seed drill is far more common and it is what we recommend, for the sake of control. In broadcast sowing the seed is scattered on the surface by hand or with a fertiliser spreader, the amount going on each decare cannot be controlled and more seed than necessary is generally used. With a drill the amount is set, the seed is placed in rows at the required depth and the kilograms per decare can be checked by weighing. Drill settings vary from machine to machine, so we do not give a specific setting; the machine’s own manual and weighing over the first few decares give the right adjustment.
Finally, the bag count. Our seed comes in 50 kg bags, and at 25 kg per decare one bag covers two decares. For a ten-decare field five bags are enough, six where the upper end of the range is chosen on dryland.
To return to the question we started with: how many kilograms per decare is written on the data sheet, and that range already allows for emergence loss. Where to stand within the range is decided by the field’s water, and hitting the rate is what the drill is for. Extra seed is not a safeguard; more often it is a hidden cost. To see the data sheets of the three barley varieties side by side, the comparison table on our barley seed varieties page can be consulted. Let us know your field size and water situation and our agronomist will work out how many bags are needed for your conditions: +90 506 101 01 50.