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www.ilvo.vlaanderen.be [email protected] +32 9 272 27 82 Comparison between novel and traditional spray application techniques in strawberries Can spray boom systems improve the spray results in a strawberry crop compared with the traditional spray gun? What is the effect of nozzle type and setting on spray boom deposition results? D. NUYTTENS, P. BRAEKMAN & D. FOQUE Institute for Agricultural and Fisheries Research (ILVO) – Technology & Food Science Unit – Agricultural Engineering Burg. Van Gansberghelaan 115, bus 1, 9820 Merelbeke (BELGIUM) Elsanta strawberry crop Average height ± 0.40 m Growth stage: end of fruit production Approx. 8300 running metres ha -1 Canopy spray deposition measurements Mineral chelates (Fe, Co, Cu, Mn, Mo, Zn; 100 mg L -1 ) • Same collectors for the different applications • Analysis: Inductively Coupled Plasma (ICP) Deposition measurements • were normalised to a concentration of 100 mg L -1 in the tank and an application rate of 1000 L ha -1 ground surface • are expressed as relative values (%) compared to the maximal feasible deposition, assuming a perfectly uniform distribution of the spray liquid on the contours of the crop canopy Filter paper collectors (7.6 x 2.6 cm²) • Three collectors on the crop canopy → spray distribution • Two inside the crop → crop penetration • Five plants were selected as repetitions Research questions Materials and Methods Results and discussion Reference : Braekman P, Foqué D, Messens W, Van Labeke M-C, Pieters J G, Nuyttens D. 2010. Effect of spray application technique on spray deposition in greenhouse strawberries and tomatoes. Pest Management Science. 66(2): 203-212 Spray application techniques 3-nozzle vertical spray boom Handheld spraygun application VMD: Volume median droplet diameter v vol50 : Average droplet velocity Deposition (%) on the crop contours for the different techniques Deposition (%) on the inside of the crop for the different t Deposition (%) on the crop contours for the ≠ collector positions Deposition (%) on the inside of the crop for the ≠ collector positions Conclusions (automated) vertical spray booms are a valuable alternative for the traditional spray gun: operator exposure↓, labor-intensity↓, spray deposition and uniformity ↑ Nozzle choice significantly affects spray deposition and penetration Highest depositions with the air inclusion or extended range flat fan nozzles at their recommended spray pressure Significant effect of collector position on deposition (2 > 3 > 1) Important variability of the deposits measured at each sample point Significant effect of collector position on deposition (4 > 5) → Deeper position in the crop Important variability of the deposits measured at each sample point Clear effect of spray system on deposition: boom ~22-60% vs. gun ~20% Difference most pronounced on top of canopy: boom 13.1% vs. gun 4.5% Highest deposits with ID 12002, Albuz AVI-Twin 11002 & TeeJet XR 11003, all at their recommended working pressure of 6.0, 6.0 and 2.5 bar Deposition with gun was only significantly lower than boom for ID 12002 nozzle Best crop penetration with the ID 12002 nozzle: big and fast droplets Increasing spray pressure above the recommended one and spray angling did not improve penetration
