Effect of protective shields on drift and deposition characteristics of field sprayers

Abstract

Field trials were conducted to determine the effectiveness of shields in reducing off-target droplet drift from ground-rig sprayers. Sprayer booms ranging in width from l0 to 13.5 m and equipped with com--e.ciully avaltitti shields *ere operated along a 150-m swath in a field of approximately 2O-cm-tall spring wheat in wind speeds ranging from lb to 35 km h-r. Airborne drift was measured using aipiriteO air samplers. ihe ure of an 80" flat fan tip (8001) at a pressure of 275 kPa and a ground speed of 8 km h -I resulted in 7 .5% of the 50 L ha -r spray solution drifting off the target area. The ule of protective cones with 8fi)1 tips without lowering the boom reduced airborne drift by 337o at_ a 20 krir h-r wind speed, while a Si-gSn drift reduction was accomplished with the combination of solid or perforated s-hielding and lowering the sprayer boom. Increasing the application rate to 100 L ha -r by using 8002 tips reduced drift of the unshielded sprayer by 65% . Decreasing application rate to 15 i ha-riy using tOOOtZ tips increased drift by 29% despite the use of a shield. Off-target drift increased withincreaiing wind speeds for all sprayers, but the increase was less for shielded sprayers and coarser sprays. The decreased droplet size of spray from 1 10" tips increased drift when the boom height was the same as for 80o tips. High wind speeds, lower carrier volumes and finer sprays, 110" tipJ, and solid shields tended to dicrease on-swath deposit uniformity, whereas a perforated shield or cones did not affect deposit uniformity.

Evaluation of 2,4-D-Choline Based Herbicide Systems in 2,4-D Tolerant Soybean (<i>Glycine max</i> L.)

“…Nozzles that produce coarser size droplets will minimize 2,4-D particle drift and subsequent injury to sensitive crops in adjacent fields [23]. However, application instruction, including nozzle types, time of day of application along with other ways to mitigate drift injury are accompanied with the new herbicides technologies to help reduce misuse by growers and commercial applicators [22].…”

“…Tolerance was achieved through the insertion of bacterial genes into soybean that allows the plant to metabolize 2,4-D. [21]. Previous research has documented that up to 16% of spray solution can physically drift from the intended application area [22]. Therefore, growers will need to exercise caution when applying these new herbicide technologies to avoid injury to sensitive crops in adjacent fields.…”

The Effect of Dicamba on Peanut When Applied during Vegetative Growth Stages

“…Herbicide drift can be linked to many different factors: nozzle type, boom height, wind speed, pressure, spray formulation, sprayer speed, volume per area, and other environmental variables (Wolf et al, 1993). Grover et al (1978) reported that herbicide drift amounts can range from 1 to 8%, and Wolf et al (1993) indicated drift, without spray nozzle shielding, can reach 16% off target.…”

Airborne off-target losses and deposition characteristics from a self-propelled, high speed and high clearance ground sprayer

“…The field layout, similar to that of previous field trial series Wolf et al 1993), was a set of four rectangular swaths, each 18 m wide and 150 m long . These were oriented 45°apart, so as to handle any potential wind direction within ±22.5°.…”

“…More recently, the need for continuing information on field application technologies, including drift reduction, has again been stressed (Crutchley 1995). New devices and operating systems are continually being introduced to improve application efficiency or to reduce off-target spray drift (Grover and Reed 1990;Wolf et al 1993). One of these innovations is the "low-drift" tip, which has been suggested for improved drift management (Anonymous 1995).…”