Reducing Herbicide to Tackle Weeds on Arable Land

A study from France has shown that it is possible for farmers to reduce the amount of herbicide they apply to their fields, and still tackle weeds effectively. Herbicides are commonly applied to crops to manage weeds but can be expensive, get into water courses and have adverse impacts on non-target species.

Over six years, the researchers compared the effectiveness of four different ‘Integrated Weed Management’ (IWM) cropping systems, varying in terms of crop rotations; soil tillage; mechanical and chemical weeding and crop management, with a standard system.

Unsuprisingly the researchers found that the mean annual number of herbicide treatments in the IWM fields was lower. They also found contamination levels in ground and surface water, the air and the effects on non-target organisms were lower in these fields. Significantly, the researchers found that IWM systems are about as effective at weed control as control by herbicides and therefore farmers should be able to successfully reduce reliance on these chemicals.

Although the benefits of using an IWM system, for both the climate – due to reducing the need to make, prepare and apply herbicides, and so associated greenhouse gas emissions – and biodiversity, should be positive, the researchers conclude that the complexity of managing fields using an IWM system may make it difficult for farmers to do so. They also suggest that some of the management techniques may increase soil erosion, although they do suggest a way this could be tackled.

Chikowo, R., Faloya, V., Petit, S. and Munier-Jolain, N.M. (2009). Integrated Weed Management systems allow reduced reliance on herbicides and long-term weed control. Agriculture, Ecosystems and Environment. 132:237-242.