Last changed: 16 January 2023
Drones flying over leys

Vall-scanner is a proposed tool and method for assessing leys using affordable drones, and is a partnership between SLU and Hushållningssällskapet.

The nitrogen requirements of a mixed ley are affected by the existing proportion of legumes. Making a reasonable estimate of the botanical composition of legumes and grass at field level is crucial for good fertilization planning and obtaining the required yield and quality. Both a deficit and a surplus of nitrogen have a negative effect on the economy and the environment.

Watch the film: "Vallscanner-using cheap drones for scouting leys"

At present, relatively unfounded guesses are often used. It is difficult and time-consuming to assess the proportion of clover in the field. There is also a lack of time to make an assessment of the current situation when it is time to apply fertilizer in grassland, both in the spring and for regrowth.

The vall-scanner system will collect images of the ley with the help of drone and then analyze these to generate useful information. During the flight, the drone will visit selected locations in the field and take photos at low altitude. In early spring, before the crop thickens, image analysis can convey information about botanical composition and density. By using this information, farmers and advisors can view images and compiled information and make more informed decisions about fertilization levels and any need for auxiliary sowing. The system will provide better knowledge of the conditions of individual fields. It must be a time-efficient method to use during a hectic period of the growing season, providing benefits for farmers.

The vall-scanner had a pilot development season during 2021, as part of the Ag-Tech Challenge ( We hope to find funding for further development of the system.