Developments in physical weed control

Description

Physical weed control is the key method for reducing negative impacts of weeds in organic cropping systems, and remains important even on many conventional vegetable farms. Inter-row cultivation is generally effective, but controlling intra-row weeds remains a challenge. Well-timed use of torsion, finger and tine weeders can control intra-row weeds, with impressive efficacy observed when the tools are combined or ‘stacked’. However, selectivity of intra-row tools depends in part on maintenance of a size differential between crops and weeds, which is particularly challenging in slow-growing, direct-seeded crops. Recent advances in GPS and camera-based guidance system technologies permit high working rates, and increasingly precise, close-to-the-row tool adjustment. Innovative tool design, parameter-based values for adjustment and choice of tool, and advances in mechanistic understanding of weed seedling mortality and crop injury could elevate physical weed control to a level of performance farmers have grown to expect from modern herbicides.

Table of contents

1 Introduction 2 Tillage 3 Physical weed control: overview 4 Tools, weeds and soil conditions 5 Weed–crop selectivity 6 Fundamental problems with cultivation 7 Future research priorities 8 Where to look for further information 9 References