If the farmer can make do with spraying a single droplet of herbicide on a single weed plant instead of covering the whole field in a cloud of herbicide droplets, then most people would probably be quite pleased. Precision spraying, as it is called, is easier on the farmer’s wallet and the environment.

Theoretically, it is already feasible. The technology for precision spraying is available in several EU countries – including Denmark. The best of the systems only need to be tested in the real world. An EU project is paving the way for doing just that.

Together with scientists from several other EU countries, academic employee Ivar Lund from the Department of Agricultural Engineering, Faculty of Agricultural Sciences, University of Aarhus, is in the process of surveying the available technologies, calculating how much can potentially be saved using the new technologies, and investigating how they can be carried out in the real world. This is all part of the EU project ENDURE.

Gathering knowledge

To start with, the scientists are gathering information about products, equipment and use of precision spraying in order to get an idea of what is already in place. The Danish contribution to the project will be – in addition to the role of coordinator – to gather available knowledge about precision spraying in field crops. The Dutch partner in the project will collect knowledge about precision spraying in orchards and the Spanish partner will do likewise in vineyards.

Besides ploughing through available literature and products, the scientists will investigate how much pesticide can actually be saved using selected systems in case studies. At the Faculty of Agricultural Sciences the studies will concentrate on cell spraying of weeds in maize.

- We have developed a sprayer that can divide the field into cells that are smaller than a cell phone – they can actually be as small as 3 x 11 cm. The sprayer is equipped with a special camera that can detect when the sprayer moves over a cell that has a certain amount of green growth in it. The sensor can also discriminate between weed and crop. If there is a certain amount of weed growth, then the sprayer is activated to spray precisely where the weeds are. That means that only parts of the field are sprayed (where the weeds are) instead of the whole field, explains Ivar Lund.

Spring studies in maize

Demonstration of the spraying system in maize will start this spring. The aim is to measure how precisely the sprayer hits the weeds, i.e. the treatment accuracy. The scientists will also calculate how great the potential is for reducing the amount of herbicides.

- We know that some techniques can cut herbicide use by half, depending on weed density. Spot spraying has in some cases reduced herbicide use by over 80 percent. And in the weed spots themselves there are also ”bare spots” where even more herbicide can be saved using ultra-precise spraying systems, says Ivar Lund.

Until now, the problem has been that the farmer first has to go out and count the weeds in the field, then go back to his computer to prepare a spraying map, and then get into the tractor and spray. In order to be efficient things must be done in one smooth operation, for example using a system that automatically collects information about the position of the weeds whilst driving the tractor with the sprayer.

In order to optimise the technology it is necessary to develop systems that are good at detecting and recognizing not only weeds but also diseases and pests. Once the good systems are identified and documented, the next step will be to test them in practice – but that will not be up to the scientists.

- We can document that the systems work, but we don’t do product development and design. If and when the farmers can buy the systems depends on whether the systems can catch a company’s interest, says Ivar Lund.

ENDURE, European Network for the Durable Exploitation of Crop Protection Strategies, is a so-called “network of excellence (NoE)” which is financed by EU’s 6th Framework Programme.

The aim of ENDURE is to create a European research network that will also exist after the funding of ENDURE ceases at the end of 2010. The research activities aim to achieve a better understanding of pest biology and the interaction between plants and their pests and, based on this knowledge, to develop new, innovative control strategies in which dependence on effective pesticides is reduced compared to the present. This can be achieved by combining analytical and system-based approaches and by promoting collaboration between biologists, agronomists, economists and sociologists. Another important goal of ENDURE is to ensure that new knowledge is communicated to all relevant parties: farmers, advisers, the industry, politicians and, not least, consumers.

Read more about ENDURE at www.endure-network.eu .

For more information please contact: Academic employee Ivar Lund, Department of Agricultural Engineering, Faculty of Agricultural Sciences, University of Aarhus, telephone: +45 8999 3030, e-mail: Ivar.Lund@agrsci.dk

Text: Janne Hansen