Recent efforts to reduce the amount of pesticides being applied via sprayers tend to centre on identifying individual weed plants in a crop and eliminating them with a directed dose of herbicide.

While attention is being focused on this aspect of field hygiene, there still remains the need to apply fungicides and insecticides to the whole crop, and this does not generally receive as much attention.

Band spraying and beyond

Yet, there are companies looking at this and one such is Herbert Dammann GmbH of northern Germany.

row crop sprayer by Dammann
Nozzles providing a narrow spray cone ensure direct application of the pesticide to the target

The technique of applying a band of spray along single rows is not a new idea by any means, yet, as has been noted by other researchers, it does depend on the accuracy of application if it is to work well.

Horsch, is one company that is exploring this technique and, in conjunction with the Julius Kuhn Institute, has found that while a reasonable degree of accuracy can be obtained on level fields, hilly ground can pose problems.

Lines that are less than optimal

The issue is as much one of keeping the drill straight during sowing, as it is trying to follow the resulting crop rows. Even when auto steering was used, the lines deviated from the optimum.

One approach to overcoming this problem is to adjust the position of the nozzle in real time as the sprayer passes through the crop.

It is the approach that Dammann is taking with a rail mounted underneath the boom that may be moved horizontally in response to the changing position of rows relative to the tramlines.

Dammann camera guidance

The company refers to its development as ‘Row-Specific Nozzle Positioning’. The nozzle is guided precisely over the row by active control, using a camera.

This way, it claims that the pesticide is only applied to the necessary area, reducing the potential for drift and significantly reducing pesticide consumption.

The system is most suitable for cultivation in row crops, such as field-scale vegetables, although it is suggested that when used as part of a total weed control plan, it will work well alongside interrow hoeing.

Setting up

The first adjustment is made manually before application with the nozzle width being adjusted manually to match the row width, the boom is then set in position above the crop as required.

Dammonn spray boom rail
The secondary rail is moved laterally under camera guidance

During application, the movable rail and sensors take over the positioning of the nozzles to ensure precise distribution of the crop protection agents.

Dammann notes that the system enables band spraying in row crops with large working widths and is an ideal complement to mechanical weed control.

Dammann develops for row crops

Although there is no suggestion at present that the company is looking to extend the concept to the major cereal crops, there is pressure within tillage farming to reduce all herbicide use.

More precise control over how these liquids are applied to the target is obviously desirable and the technology being developed for the treatment of row crops will, at some point, spill over to the major field crops as well.

Although experiments with adjustable nozzle position date back nearly 20 years, Dammann presented its system for the first time at Agritechnica 2019 and development is still ongoing.