| Front page | | Contents | | Previous |

Cleaner Technology Projects in Denmark 1996

Automatic Systems for Row-Specific Weed Control

The report consists of four main sections. In section one the prospects and limitations of various mechanical weed-control methods and band spraying are reviewed. In section two various principles of positioning field machinery are described. In section three the financial feasibility of mechanical weed control in beets together with band spraying is assessed and compared with conventional spraying. The last section includes a general discussion of factors that are important for farmers if they are going to adopt mechanical weed control supported by automatic guidance systems. The discussion is mainly focused on weed crops.

The available information on automatic guidance systems is mainly based on Swedish research and experiences, but also in the Netherlands and England technical research on guidance systems is currently being carried out.

Tractor hoeing and band spraying are hardly used by Danish farmers. Therefore, little incitement for technical refinement of machinery for row specific weed control has been demanded. In general, Danish farmers are not aware of the possibilities of adopting new technologies to improve row cultivation and spraying.

In Sweden automatic guidance systems have been adopted by farmers and approximately one third of the sugar beet area is tractor hoed and band sprayed. However, only a small proportion of this area is hoed and sprayed with machinery provided with automatic guidance. The positioning of the commercial guidance system in Sweden is based on a furrow created between rows at sowing. This is a so-called relative location technique relying on specially provided marks.

In several countries plant guidance systems are currently being developed. Many systems are computer vision-based and are capable of detecting crop rows directly by sensors. Also site oriented guidance systems are currently being developed. A Swedish system currently being developed uses a revolving laser system and a few reflectors around the field.

Development of automatic guidance systems for row specific weed control will make it possible to improve competitiveness of weed-control methods based on mechanical weed control. However, farmers do not have to wait before they replace conventional spraying with band spraying and mechanical cultivation in row crops. Economic assessments show that many Danish farmers can improve profitability immediately if they quit spraying the total area in crops with high herbicide expenses and instead use mechanical cultivation and band spraying.

The report concludes that it is already now technically possible to use automatic systems for weed control in connection with hoeing and band spraying. The available systems are based on guidance by furrows that are established in the sowing process, but other systems are being developed. Automatic systems have a number of advantages over hoeing and band spraying manually carried out. The advantages are a better exactness, which provides a reduced usage of herbicides, a greater capacity and a better work environment. In row crops the usage of herbicides can be reduced by up to 80% compared to broad spraying, which makes the method remunerative in many cases. The method is not remunerative in cereals.

The disadvantage is that it takes longer time to hoe and band spray than to broad spray. This requires the necessary time in each farm to use this method. It also requires an investment. But the greatest disadvantage is that the method is subject to some uncertainty regarding the effectiveness of it, because there is no Danish experience to draw on in the field.

Author/ institution

Jesper Rasmussen.
Statens Planteavlsforsøg. Afdeling for Ukrudtsbekæmpelse og Pesticidøkologi.

This report is subsidised by the National Council for Recycling and Cleaner Technology.

ISSN no. 0908-9195
ISBN no. 87-7810-717-2

| Front page | | Contents | | Previous | | Top |