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Unsprayed field margins: effects on environment, biodiversity and agricultural practice

A management strategy has been developed for field margins to reduce pesticide drift to non-target areas and to promote biodiversity on arable land. To this end, 3 and 6 m wide strips along the edges of winter wheat, sugar beet and potato crops have been left unsprayed with herbicides and insecticides and compared with sprayed edges. The effects on pesticide drift, arable flora, inverte-brates, vertebrates, costs and acceptance to the farmer were studied. This article reviews the most important results.

G.R. de Snoo
01 januari 1995
Thesis in Leiden Repository

Interviews with farmers show that field margins were sprayed intensively. Drift measurements demonstrated that the creation of unsprayed buffer zones of 3 m wide proves to be a very effective way of reducing pesticide drift to the ditch (by about 95%) and risks to aquatic organisms. In the unsprayed edges presence and abundance of arable plants increased substantially. The impact on epigeïc soil invertebrates was relatively minor. However, there was a pronounced effect on insects living on plants. The number of visits by Motacilla flava flava, an insectivorous bird, to the unsprayed edges was also higher.

Cost-benefit analysis based on the yield losses shows that in winter wheat and potatoes unsprayed crop edges can well be adopted in agricultural practice. In sugar beet, however, the cost is too high. However, for agronomic, farming equipment related and socio-psychological reasons farmers prefer unsprayed cereal edges or grass strips in stead of potato edges. From their perspective a flexible width of the unsprayed crop edges is the most important aspect for acceptance in farming practice.