Technical accuracy of orchard sprayer used in intensive fruit and vineyard production in Republic of Serbia

The technical accuracy of the machine is a prerequisite for the effective implementation of chemical protection in fruit and grapevine production. The paper presents the results obtained during the control testing of 50 different models of orchard sprayers, with different period of exploitation in growers throughout Serbia that are used in intensive fruit and grapevine production. During the control testing, a large number of parameters were monitored, using standardized methods and test procedures. Comparison of the obtained data was applied to four groups of orchard sprayers (defined by the period of the exploitation). The technical accuracy of the individual orchard sprayer is expressed by the coefficient of the technical correctness (Cta) according to individual marks of the tested parameters of orchard sprayers. Out of the total number of investigated orchard sprayers, 12% of the orchard sprayers are in exploitation for less than three years, while the largest number of orchard sprayers, and 42% is in exploitation for seven years or more. The technical accuracy of Group 1 orchard sprayers was sufficiently high, except for the parameters related to the Measuring regulatory system (Cta = 0.80) and the Nozzles (Cta = 0.86). In Group 2, a decrease in the coefficient of technical accuracy in all parameters was observed with respect to the sprayers from Group 1, which was particularly pronounced for Agitators (Cta = 0.50) and Nozzles (Cta = 0.68). The orchard sprayers from Group 3 are characterized by a low coefficient of technical accuracy for the Nozzles (Cta = 0.37), while Group 4 orchard sprayers have a very low coefficient of technical accuracy in all tested parameters. The level of technical accuracy of the orchard sprayers used in intensive fruit and grapevine production is directly dependent on the period of their exploitation