January 9, 2012
Danish scientists focus on reducing herbicide use
The amount of pesticides applied by farmers to control weeds, insects and diseases can be reduced by using new technology that Danish scientists are developing with support from The Danish National Advanced Technology Foundation.
"We expect that by using an intelligent spraying boom with an integrated camera, a vision system and a module for treating the photographs, as well as individual control of the closing and opening of each nozzle, the farmer can reduce the use of herbicides by over 50%," says senior scientist Peter Kryger Jensen from the Department of Integrated Pest Management at Aarhus University.
The idea is simple: to spray only when there are weeds present. In a previous project supported by the Environmental Protection Agency the scientists developed a robotic spraying machine that could self-drive and spray in the field. Now the task at hand is to get the robot to "think" so that it only opens the nozzles when there are actual weeds to be found on the spot a€" and when the scientist talk about the "spot" they are talking about cell areas measuring a few square centimetres.
"In the earlier project we developed a sprayer that could drive on its own and spray very small cells," says Jensen.
The next step is to produce a prototype for an intelligent spraying boom that can register the need to spray and, if there is a need, then to carry out the task- all of it within a very short space of time.
First the system takes a picture of the crop and any weeds in the area. The system must then differentiate between crop and weed, identify the weed species and decide which nozzles on the spraying boom to open.
Since the driving speed in the field is typically 2-3 m per second, there is only a very short time span from the picture is taken until the nozzles open and the weed is treated.
"We have found a valve that can react within six milliseconds," says Jensen.
Studies will be carried out with the intelligent spraying boom in the corn fields belonging to the Department of Integrated Pest Management in the upcoming growing season. The scientists will investigate how well the weeds are hit and they will test various nozzles for their opening and closing speeds and their ability to atomise correctly.