Integrating Physical and Cultural Methods of Weed Control – Examples from European Research

Summary in the original language of the document

Increasing concerns about pesticide use and a steadily increasing conversion to organic farming have been major factors driving research in physical and cultural weed control methods in Europe.
This paper reviews some of the major results achieved with non-chemical methods and strategies especially adapted for row crops (e.g. corn, sugar beet, onion, leek, and carrot) and small grain cereals (e.g. barley and wheat). In row crops, intra-row weeds constitute a major challenge and research has mainly aimed at replacing laborious hand weeding with mechanization. A number of investigations have focussed on optimising the use of thermal and mechanical weeding methods against intra-row weeds, such as flaming, harrowing, brush weeding, hoeing, torsion weeding and finger weeding. And new methods are now under investigation such as robotic weeding for row crops with abundant spacing between individual plants and band-steaming for row crops developing dense crop stands. The strategic use of mechanical weed control methods in small grain cereals has been another area of considerable interest. Weed harrowing and inter-row hoeing provide promising results when they are part of a strategy that also involves cultural methods such as fertiliser placement, variety choice, crop seed vigour, and crop seeding rate. Positive interactions between preventive and cultural factors and direct physical methods have been less pronounced in row crops. Although research in preventive, cultural, and physical methods have improved weed control in row crops and small grain cereals, effective long-term weed management in low-external input and organic systems can only be achieved by tackling the problem in a wider context, i.e. at the cropping system level. Basic principles of this approach, examples of cover crop and intercropping use for weed suppression, and an application in a two-year rotation are presented and discussed.