A field investigation to examine the effects of sprayer type ground speed and volume rate on spray deposition in florida usa citrus

Whitney, J.D.; Salyani, M.; Churchill, D.B.; Knapp, J.L.; Whiteside, J.O.; Littell, R.C.

Journal of Agricultural Engineering Research 42(4): 275-284


Accession: 006942381

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Two sprayers (A and B) were used to spray metallic copper on grapefruit trees at 4.4 kg a.i./ha in a randomized block field experiment. Sprayer A required 97 kW of power and was operated at all combinations of three ground speeds (1.6, 2.8, and 4.0 km/h) and three spray volumes (1170, 2340 and 4680 l/ha); sprayer B required 37.3 kW and was operated at all except the 4.0 km/h and 4680 l/ha combination. Copper depositions was assessed on leaves that were collected from 18 locations in one quadrant of the tree. The 18 locations were combinations of three heights (1.5, 3.2 and 4.9 m), two radii (outer canopy and 0.8 m inside canopy), and three azimuths (0.degree., 45.degree., and 90.degree. to tree row line). On the lower leaf surface, copper deposition was not affected by sprayer, ground speed, or volume. All tree location factors (height, radius, azimuth) did have a significant effect. Deposition was greatest at the mid-height, outer canopy, and 90.degree. azimuth, and lowest at the low height, inside canopy, and 0.degree. azimuth. Upper leaf surface deposition was significantly affected by all factors. Within each factor, the greatest deposits were associated with sprayer B, 2340 l/ha, 4.0 km/h, 1.5 m height, outer canopy, and 90.degree. azimuth. Total leaf surface deposit was significantly affected by sprayer, volume, and ground speed with sprayer B, 2340 l/ha, and 4.0 km/h having the highest mean deposits. Azimuth, height, and radius all had a significant effect on mean deposits with the 90.degree. azimuth, 3.2 m height, and outside canopy having the highest deposits.