When we think of field margins, in the first place we think of flowering margins that attract beneficials (insects that eat pests, pollinators). In contradiction to the name, a field margin doesn’t necessarily have to be at the border of the field. Since the effect of a flower strip can be average about 50 m to 100 m, a strip in the middle of the field can provide a benefit in both directions. Just like for hedgerows also for field margins an informed choice needs to be made concerning the species to avoid the attraction of harmful insects.
A second important function of the field margins is the use as a buffer strip. This is a strip between the field and the watercourse which is not fertilized and the use of plant protection products is not allowed. Aim of the strip is to avoid the leaching of nutrients or plant protection products to the watercourse. This strip is sown, so also here an informed choice of the used species, which have a positive influence on the rest of the field, must be made.
Interesting links:
Report on social cost-benefit analysis of field margins (RIVM) (English)
Report on promotion of beneficial organisms for pest control and pollination in open crops. (Dutch)
Field guide natural enemies, development and characteristics (HoGent and PC Sierteelt) (Dutch and English)