‘Per plant farming’ is the rationale that underlines the creation and ongoing development of the Small Robot Company based near Salisbury in the UK.

Rather than look at a tractor and work out how to automate it, the company has started with the question of how farming would look if we started all over again with a blank canvas and present technology.

The tractor as we know it would probably not exist suggests Sarra Mander, communications officer for the company. This may not be an entirely original thought, but the company has actually taken on the challenge of changing the way that crops are managed and tractors are used.

Based on pioneering work undertaken at Harper Adams University over the last 20 years, the concept of using ever bigger tractors to ensure timeliness of operation is being challenged.

Instead, the company is promoting the idea of precision, which it sees as managing each plant on an individual basis, or ‘per plant farming’, as they refer to it.

Wilma map
The system is capable of locating individual weeds within a field

The idea may sound rather unrealistic to many, but it does open up huge possibilities. This was recently illustrated by the survey of a 6ha field of wheat.

A total of 12.7 million separate crop plants were counted within the area. In addition, there were 250,000 weed plants in a field that was recognised as having a weed problem.

Given such a situation, the normal remedy would be to douse the whole field and all the plants, crop and weed, with a herbicide.

What the Small Robot Company is aiming to do is remove each of those weeds one at a time, rather than waste chemicals on the plants that the farmer wishes to keep.

Zapping weeds
Electrocution of individual weeds is one option being explored

This task may not necessarily involve the use of chemicals at all. Once the type and position of a weed is discovered, a robot with a multifunctional arm, may be guided to it for electrocution, or it may simply be dug out rather than spot sprayed.

A bonus of weed species identification is that beneficial weeds, such as clover or flowering plants visited by bees, could be left alone if they did not pose a significant threat to yields.

Tom in field
The primary robot is named Tom

Although it is the issue of weeds that the company is addressing at present, its road map into the future envisages disease control, spot application of fertiliser and the real time assessment of soil health, including organic matter content and nutrient status.

Per plant farming; the next green revolution?

All of these ideas are being actively pursued by the company and its associates, and with good reason.

In trial plots, a doubling of yields has been obtained through plant micromanagement, although they are not getting carried away by this, noting that scaling up such an achievement faces many hurdles.

Should such yield increases become a reality, then history may view the advent of field robotics as a further revolution in agriculture.

This would be similar in scale to that of the green revolution of the 20th century. Yet Sarra Mander is adamant that, for now, it is a matter of evolution, one step at a time, in realising the huge potential.

Visual sensors and GPS accurate to within 1mm are located on the robot's boom
Visual sensors and GPS accurate to within 1mm, are located on the robots boom

Meet Tom, Dick and Harry

The Small Robot Company has taken a long hard look at the question of how to translate these ideas into practice.

Its solution is to divide the various tasks up between three robots named Tom, Dick and Harry.

These three are joined by a fourth entity by the name of Wilma, but she is the software that sits in the office and on the robots, coordinating all the data and action.

The farming system envisaged places Tom on the farm all of the time. He is the eyes and the ears of the group, constantly patrolling the fields looking for problems and assessing soil conditions.

Dick treats the individual plants
Dick is equipped to eradicate weeds identified by Tom

Where action is required, he can call upon either Dick or Harry. The former is charged with weed control using the methods described above, while the latter is planned to be the haulier, taking nutrients and other inputs out to the field.

It is worth noting that only the first robot need be present on the farm all of the time. The other two can be moved between farms as and when required.

Running on-farm generated electricity, the energy cost would be zero at point of use.

Harry concept
Harry in the concept stage

Naturally there is a cost to all of this and the final figure is still open to debate. The company does not see itself as a manufacturer of tractors in the traditional way, rather, it is a supplier of a new farming method; it is offering a service rather than a machine.

However, it is possible to start pencilling in a few figures. The primary limitation is the present cost of weed control which stands at around £400 (Approx. €465) per hectare.

The system would hardly attract customers if it were any more. There would also be different ways of fine tuning the bill, by taking into account the number of weeds killed, for instance.

Such a crude comparison with present methods may be misleading, as the extra yield, reduced soil damage and cut in inputs would further increase the profitability of the farm overall.

Robot and tractor
Robots and tractors are likely to be working together well into the future

Currently, the company does not see itself as replacing the mainline tractor anytime soon; harvesting is one operation that is still beyond the reach of this type of machine.

Yet there are many other opportunities which this clean sheet approach will present, and the company is fully open to new ideas brought to them by both technicians and farmers themselves.