Site-specific weed control

Abstract

Spatial and temporal variations in weed seedling distributions in arable fields are analysed. It is described how weed distributions can be assessed by manual grid sampling and by using sensor technologies from the near range. The potential for herbicide savings using site-specific weed management in different crops is calculated. Two different approaches for site-specific weed control are presented. First, an offline-approach based on georeferenced weed distribution maps and secondly a real-time approach combining sensor- and patch spraying technologies. The decision rules for patch spraying should take into account density, coverage and yield loss effects by weed species, its growth stages and costs of weed control. Herbicide savings using precision weed control varied from 20 to 70 %. Real-time patch spraying is the most economic treatment followed by map-based site-specific weed control. Uniform herbicide applications and uncontrolled treatments gave the lowest economic return. Several studies showed that weed species distribution remained stable over time when site-specific herbicide applications were realized based on economic weed thresholds.