Home » Issue 26-2023 » Company insights » Solus – The sowing method of the future? Potentials and limits (Philipp Horsch)

Solus – The sowing method of the future? Potentials and limits

The future topics in the seeding sector are mainly centred on placement precision. HORSCH is working on a new seed drill which is to meet current and future requirements. Philipp Horsch explains the special features and potentials of the new narrow seed drill Solus and where the limits are.

One of the future topics that plays a major role in the sector of seeding is precision, i.e. depth, standing area and embedding of the seed. HORSCH has been dealing with and improving these points intensively for many years. Over the years, a better and better placement level of cereals and rape seed has been achieved with disc coulter technology. In the course of time, new challenges were added, like for example the reduction targets in chemical crop care, the discontinuation of agents or the changing climatic framework conditions are things we have to react to.
“The most precise coulter technology we have at our disposal today is the single grain row of our Maestro line”, Philipp Horsch summarises. The precision comes from the combination of a double disc coulter with a lateral depth control at the point where the seed is placed. “We can maintain the depth much better and more constantly if two control wheels do not run behind the row, but directly at the seed disc”, he explains the principle. Moreover, the regular consolidation effect of the two lateral depth control wheels on the left, the right and below the seed furrow creates a perfect, even germination zone for the seed. This and the better depth control are two essential factors for the regular and safe emergence we know from maize seed drills.
To benefit from the precision of a single grain unit, larger row spacings are required. With the Pronto DC row spacings of 15 cm were established. “But for narrow sowing with single grain units, we are talking about row spacings starting at 22.5 cm. The experiences of the past years showed that a larger row spacing works in many regions from an agronomic point of view and that the yields do not decrease. In this respect, we feed on a lot of knowledge “, Philipp Horsch explains.


Already 17 years ago, HORSCH started to deal more intensively with the topic of singulation. The first system that was built at that time was an overpressure system with a flexible shoot line and a perforated disc. The objective was to singulate and to apply small seeds like cereals and rape as well as the traditional row seed maize, soya, beets and sunflowers. This was when HORSCH started to work with overpressure and shoot systems.
“However, during the development process we decided to start with a mechanical system for the singulation of only maize and sunflowers which at that time we bought from an American manufacturer“, Philipp Horsch describes the development path.
At the same time, HORSCH started to develop and launch the SingularSystem. The core of the development is a metering device that uses centrifugal force to singulate cereals, especially rape and wheat, with a high frequency. To guarantee an optimum embedding of the seed the well-proven TurboDisc double disc coulter was extended by a drop tube, a skid and a catching roller. “We gathered a lot of experience with the SingluarSystem which we now benefit from in our new project. We are especially working on the coulter technology so that we are less dependent on perfect seedbed conditions!”
The next big step was the development of the current single grain metering device. HORSCH developed a vacuum and an overpressure metering device on a technically very similar basis. The AirVac and AirSpeed technology is based on the idea of realising utmost precision with a very low adjustment effort on the one hand and highest possible flexibility with regard to crops on the other hand. “Today we can meter all current single grain crops with utmost precision as well as in addition rape, wheat, rye and barley“, Philipp Horsch specifies the success. “However, due to their considerably higher seed sizes the last crops only make sense with the AirSpeed metering system. Overpressure allows for transporting significantly higher grain frequencies precisely into the seed furrow.”

First tests

About four years ago, HORSCH carried out first tests with the AirSpeed metering device on the Avatar. They had already gathered a lot of experience in the range of 25 cm row spacing, but with a single disc coulter. Disillusionment came quickly: It was not possible to catch the grains precisely enough behind the single disc coulter as the furrow was not homogeneous enough. The reason was that there was a disc on one side and a skid on the other side. Thus, it was not possible to shoot the grains precisely enough right to the centre below the catching roller.

HORSCH was not satisfied and made further efforts in this direction. “Already at that time, we started to develop a narrow seed body for maize and soybeans for the Chinese market”, Philipp Horsch states. “A slim unit that allowed for row spacings smaller than 25 cm. It has been used as standard in China since 2019.“


The next step was to place the AirSpeed metering device on the slim Maestro body and build a machine with a coulter spacing of 22.5 cm. “This follows a logic, decades of logic. New side topics constantly spur the whole matter”, Philipp Horsch says. The wide row with evenly developed plants and a more regular plant distribution in the standing area in the row can be useful for several future topics at the same time.
Among others mechanical weed control. With wider rows the space between the rows is more easy to hoe. The share of rows per metre working width is less and so is the area that cannot be hoed today. If, in the future, you want to hoe in the row, it can be realised more easily from a technical point of view provided that the plant spacings are regular resp. the space between the plants can be predicted with utmost probability. Camera technology and AI can, thus, provide significantly better results.

An improved aeration of the rows and shorter periods of wet leaves allow for achieving healthier plant populations – an essential point with regard to the reduction of chemical crop care.

In addition, there is the option for a more precise nutrient supply of the plant. Moreover, the band application of herbicides involves further potential for reducing chemical crop care measures.  
All in all, it is, of course, always about the clever use of yield reserves in arable farming. If we manage to establish regular, optimally placed populations, this will certainly be another key to higher resp. stable yields.
“Last summer we started to carry out first tests in Germany with all-over sowing“, Philipp Horsch explains. The first tests with a 6 m 3-point tool were very promising. “The new narrow seed body works. Of course, there is some need for adjustment, but basically it works”, Philipp Horsch confirms.

Solus – large area machine

The name for the new HORSCH large area product is Solus. “With this machine, we want to meet the requirements of the farmers”, Philipp Horsch explains. At the moment a 10.6 m wide, 47-row prototype of the Solus is being built. This year in autumn, the first tests are to be carried out with sowing wheat, rape, rye and barley. Beans and beet will follow next spring. Based on the experience gathered in these tests HORSCH will decide how to proceed with this line and what has to be adapted.
With the combination of the narrow seed body and the AirSpeed shoot metering device HORSCH is taking a new path that is based on the experiences and components of the past years. The central questions are if this method has what it takes to become a new trend in sowing, where the limits of the machine are and for which conditions it is suitable. “We are dealing intensively with these questions“, Philipp Horsch explains. “You always have to question the whole matter critically”, he emphasises. Late sowing or wet soils for example, can be restrictions for this method. There will again and again be situations where the parallelogram-controlled seed unit will reach its limits.  

Potentials and limits

In certain regions and arable conditions, the machine will work very well, in others less so. Because of the weight of the Solus, wet regions are particularly challenging. At good times, it will be possible to work in a highly precise way, but there will also be times when you will need an alternative. "Actually, even machines that we already have today are occasionally too heavy," Philipp Horsch adds.

On the other hand, he sees great potential in dry regions. With the Solus line, sowing depth for example can be regulated more easily than with the Pronto. This is a huge advantage, especially in view of the future and the changing weather conditions. This guarantees an ideal use of resources such as water or nutrients. 
Which markets will be the appropriate ones for the Solus line, remains to be seen. “We know the potentials. And we also know the limits“, Philipp Horsch explains. “We must not be so naïve and claim that this machine is equally suitable for all regions and conditions. But we have to take the specific requirements and conditions of the respective regions into account”. However, he is convinced that the Solus and the combination of narrow seeding and the AirSpeed system has the potential to become an “important form of sowing in the future”. Especially with the changing framework conditions in mind. But it will remain a challenge to react to volatility.
In November, at this year’s Agritechnica, the narrow seeding topic as well as the new sowing method with the combination of narrow sowing and the advantages of the AirSpeed metering device which is based on many years of experience and development will be presented at the HORSCH stand.