- The quality of emergence depends on the sowing depth.
- When do we sow shallowly, when should we sow deeper?
We will adjust the depth to the soil and humidity.
Very generally, we can say that rapeseed should be sown at a depth of 1-3 cm, in extreme conditions we are talking about a maximum of 4 cm. However, this is such a wide range that it requires a slightly more precise explanation.
Thus, in heavy sites, but with good moisture, it is possible to sow a little more shallowly, i.e. 1-2 cm. In lighter sites, we sow 2-3 cm. At the same time, we use deeper sowing in a situation where moisture conditions are not the best. In such cases, about 2 cm is generally assumed in heavier soils, and about 3 to 3.5 cm in weaker, more airy and permeable soils.
The emergence depends on how moist the soil is. The seeds must swell first, but due to their small volume, rapeseed seeds do not need a lot of water to swell.
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Not only humidity, but also light
It is worth noting here that a sowing depth of 3.5 – 4 cm is already an extreme value. We must remember that rapeseed germination occurs as a result of a light impulse, which is why sowing at a greater depth than 3.5 – 4 cm is definitely not recommended. The seeds then have less access to light, which results in uneven germination and, as a result, emergence. This is only the beginning of problems, because such an uneven plantation is difficult to protect – both from the perspective of insecticides and – perhaps above all – autumn regulation.
Generally, on good soils, rapeseed is sown at a depth of 1-2 cm, with the optimum being the range of 1.5-2 cm. On the one hand, in optimal conditions, the seeds should then be placed in soil with good moisture, on the other hand, they still have good access to light.
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How much rapeseed to sow per hectare? How to calculate the seeding rate?
On weaker ones, the standard in good humidity conditions is the already mentioned range of 2 – 3 cm.
The extreme values apply to completely different soil conditions. Sowing to a depth of 1 cm applies only to those situations when the soil is very well supplied with water at the time of sowing, and 4 cm applies to very poor water supply. Especially the second value (4 cm) should be used as rarely as possible. The standard and a certain optimum for all soils will be the range of 1.5 – 3 cm.
Rapeseed is generally sown at shallower depths than, for example, cereals. One can also conclude that sowing too deep has more negative consequences than too shallow, because it not only prolongs emergence, but also exposes plants to infection, for example, with seedling blight. And of course – one cannot go to extremes, but as a rule rape "does not like" deep sowing.
