Nozzle choice for autumn weed control
Where the target is the soil, inclining the spray from both sides using a Twin spray or alternating nozzle spray direction will offer the best spray distribution especially where soil surfaces are uneven. Where good coverage is important the Defy 3D is the ideal choice recording between 3 and 6% improvement in blackgrass control in Syngenta trials snd also offering 60-75% drift reduction.
Looked at from above, even a high population of blackgrass plants does not present very much leaf area to receive spray droplets. A fine flat fan spray is essential for coverage and inclining the spray is also an advantage here.
Hypro's Defy 3D nozzle is also suitable for this target. It is important to follow label recommendations on water volume and use between 2 and 3 bar to achieve the spray quality that is required.
Research carried out by Silsoe Reasearch Institute (TAG) has shown that an inclined spray deposits 8% more spray onto metal rods chosen to represent 1 leaf blackgrass plants.
The photo above shows blackgrass regrowth in the following crop of Linseed. Alternate boom widths were sprayed with the same product and water volume but through either a standard VP nozzle or one that was inclined at 40 degrees (Syngenta's Hawk nozzle). There is much less re-growth in the areas where the inclined nozzle was used, indicating that blackgrass control was much higher in these area - remember the only difference was the spray incline!
For advice on autumn spraying see also the FWI academy.