Comparative spray deposits by manually pulled trolley sprayer and a spray gun in greenhouse tomato crops

Abstract

The aim of this work was to evaluate spray deposition and losses to the soil in a greenhouse tomato crop during the use of a manually pulled trolley, equipped with two vertical spray booms, each with four nozzles spaced 0.50 m apart and oriented 15° upwards, in comparison with a reference treatment with a manual spray gun. The test conditions for the spray gun were established taking into account the routine practiced by farmers, consisting of treating high crops at spray volumes of nearly 1500 l ha −1 at pressures of about 2000 kPa. For the trolley, two types of nozzles were tested (standard flat fan nozzles and air-induction flat fan nozzles), at a pressure of 1200 kPa, distributing approximately the same volume as with the spray gun. Artificial targets (strips of filter-paper) fixed to upper and lower leaf surfaces in 12 zones of the tomato plants (3 heights and 4 depths) were used to collect deposits of the tracer Tartrazine. The results indicated that the deposits with the spray trolley were significantly greater than those with the spray gun. The trolley resulted in an overall deposition 40.6% and 33.9% greater than with the gun, using the standard flat fan nozzles and air-induction flat fan nozzles, respectively. Also, the spray boom reduced losses to the soil by roughly 54% compared to the spray gun. With respect to the tests made with the manually pulled trolley, the results show that the standard flat fan nozzles and air-induction flat fan nozzles behaved similarly. No significant differences were found between nozzles in the mean deposition on the canopy nor in losses to the soil.