Effect of edge of field shields on spray drift of a boom sprayer

Spray drift experiments were performed under practical circumstances to quantify the effect of a field edge barrier on airborne spray drift and spray drift ground deposit in front and behind the barrier. A bare soil surface was sprayed using a conventional boom sprayer operating at 0.50 m spray boom height, and standard flat fan nozzles (XR11004). Screens covered with 30% wind-closed windbreak shield was used to model a hedgerow and screens covered with anti-root growth cloth as a closed fence. The use of screens at the field edge reduces spray drift ground deposit as well as airborne spray drift behind the screens. Spray drift reduction was 73%-78% for ground deposition at 4-5 m distance behind the screens. Airborne spray drift at 5 m distance behind the screens over 0-3 m height was 68%-83% when measured with passive collectors. Using active sampling techniques measuring airborne spray drift almost no spray drift reduction or small increases in airborne spray drift were measured at the same distance. Spray drift deposition at the wall of the (green)house at 15 m distance from the last nozzle was on average 0.25%. When screens are positioned at 5 m distance from the last nozzle spray deposit at the wall was similar for the closed screen and 57% lower using a 30% wind-closed windbreak screen.