The role of bocage in reducing interplot spread of crop weeds

Abstract

This document considers how and when field edges can be part of the preventive measures against weeds. Four categories of the mechanical effects of hedge systems on crop weeds spreading between fields are analysed: windbreak, anti-erosion, restraint of agricultural machinery and as an obstacle to autochory. For 8 examples of weed, dispersal agents and the functions of hedge banks are compared in a table. The different functions are reviewed and a biological classification is made of the main weed species concerned, with emphasis on the possibility of curative treatment strategies with respect to the stock of diaspores and on seeking obstacles to the spread of recently introduced weed species. The optimal characteristics of hedge systems to obtain maximum effectiveness are discussed, and some suggestions for the management and design of hedge systems are thus made: height, width, the densities of the tree layer and lower layers of the hedge vegetation, edaphic properties of the hedge bank, spacing between hedges.