ASSESSMENT OF SINGLE-NOZZLE PATTERNATION AND EXTRAPOLATION TO MOVING BOOMS

The extrapolation from measurements of static deposition patterns produced by single nozzles to multi-nozzle booms was investigated for a wide range of agricultural nozzles, using a non-intrusive patternator. The spray deposit pattern was determined for seven nozzle types for single-nozzle pattern or on a three-nozzle boom at 0.198 km h-1, and for one nozzle (an XR8003VS) at a typical field speed (6.4 km h-1) in a track-room. A method for statistically separating coefficients of variation (CV) for the patterns was derived. For low throughput nozzles, there were statistically significant differences between computer simulations derived from single-nozzle patterns and the patterns produced by multiple-nozzle booms. For the XR8003VS, there were no significant differences between the computer simulation, the statistically derived pattern, or the pattern produced at 6.4 km h-1. The spray deposit patterns produced by the various nozzle combinations were examined with respect to biological efficacy using theoretical dose-response curves covering a wide range of dose responses. A CV of < 10% for a swath pattern can be biologically efficient, but 4.5% of the spray is wasted in overdosing. To compensate for uneven application, increasing dose was shown to be an inefficient means of achieving the biological result desired.