To ensure control

The efficiency of applying agrochemicals against agents that cause damage to agricultural crops, associated with less environmental contamination and lower cost, depends on several factors, including the correct calibration of the equipment. This can be achieved by mandatory evaluation of application equipment and training of its operators, as is already done in some European countries.

The agrochemicals market in Brazil went from US$600 million in 1994 to more than US$2,1 billion in 1997, surpassing US$6 billion in 2008, according to the Agricultural Inputs Thematic Chamber. These applications, when carried out in excess, can consume up to 400% more of the required amount of product. With this data in hand, it is possible to assess the importance of having control over the condition of the machines that apply most of these products, both from an economic and environmental point of view.

Considering that the identification of the current state of conservation and use of agricultural sprayers can guide new research and investments for adequate maintenance and use, in order to contribute to the reduction of costs and environmental contamination, through lower consumption and lower losses, associated with greater spraying efficiency, researchers have inspected boom sprayers used in the field with the aim of evaluating the condition of use based on the maintenance and calibration status of agricultural sprayers used in the Northern Region of the State of Paraná.

SMALL SAMPLE

One of these works was coordinated by the Research Center for Agrochemical Application Technology and Agricultural Machinery (NITEC) at the State University of Northern Paraná – Campus Luiz Meneghel, in the municipality of Bandeirantes (PR). The assessments were carried out in the Northern Region of the State, from May 2008 to November 2009. In total, 91 machines were inspected in different municipalities in the region (table 1)

Table 1: Location and number of machines evaluated.

Location	Number of machines	Location	Number of machines
Watchtower	14	Ivatuba	02
Cianorte	11	Jussara	09
Dr. Camargo	05	mandaguari	01
Florai	06	Maringa	12
Amazon	10	ourizona	04
Francisco Alves	01	São Jorge do Ivaí	13
Iporã	03

Location

Number of machines

Location

Number of machines

Watchtower

14

Ivatuba

02

Cianorte

11

Jussara

09

Dr. Camargo

05

mandaguari

01

Florai

06

Maringa

12

Amazon

10

ourizona

04

Francisco Alves

01

São Jorge do Ivaí

13

Iporã

03

ITEMS EVALUATED AND RESULTS FOUND

When considering all the variables measured in the work, it was found that 89 pieces of equipment (97,8%) presented at least one operational problem, that is, if the inspection was carried out giving, as is practiced in some countries, approval to the machines without problems , only two units of those evaluated would be capable of carrying out the work for which they were built. Among the most frequent problems are failures related to the pressure gauge, errors in the application rate and also in the flow rate of the spray tips. In table 2 it is possible to check the results of each item evaluated.

Table 2: Occurrence of problems depending on the item evaluated in the inspections.

Item evaluated	% error
Missing, broken or inadequate pressure gauge	84,6
Bad or poorly located hoses	57,1
Missing or non-functional drip guards	22,0
Presence of leaks	28,6
Missing or non-functional power strip	26,4
Missing or non-functional suction filter	11,0
Clogged or worn spray tips	67,0
Clogged spray tips	56,1
Worn spray tips	47,3
Application rate errors	69,2
Errors in application rate for more	23,1
Errors in the application rate for less	46,1
Some irregularity	97,8

Item evaluated

% error

Missing, broken or inadequate pressure gauge

84,6

Bad or poorly located hoses

57,1

Missing or non-functional drip guards

22,0

Presence of leaks

28,6

Missing or non-functional power strip

26,4

Missing or non-functional suction filter

11,0

Clogged or worn spray tips

67,0

Clogged spray tips

56,1

Worn spray tips

47,3

Application rate errors

69,2

Errors in application rate for more

23,1

Errors in the application rate for less

46,1

Some irregularity

97,8

The most frequent occurrence of simultaneous inappropriate items in the machines was seven items, occurring in 22 pieces of equipment. It was also found that 67 pieces of equipment (73,6%) had five or more inappropriate items, which indicates a high rate of simultaneous problems in these pieces of equipment (Graph 1).

Graph 1: Occurrence of the number of machines with the corresponding number of unsuitable items.

FINAL CONSIDERATIONS

The high occurrence of inadequate conditions observed in the results of the work carried out indicates the need for actions that provide better conditions for the use of these machines for the best quality in the application of agrochemicals to crops.

Excluding problems related to pressure gauges, which, even when inadequate, may not interfere with the quality of the application if the sprayers are well calibrated, problems related to the condition of the spray tips and errors in the application rate can mean, in addition to the high occurrence, also the problems that have a greater impact on the quality of agrochemical application. Thus, it is understood that better maintenance to standardize the flow between the tips could provide a more precise calibration and favor the maximization of application efficiency through better distribution of the product in the treated area, minimizing costs through less waste of agrochemicals and reducing the environmental contamination due to the slightest error in the applied dose.

It should also be considered that differences in the dose of agrochemical distributed in the operational range of the equipment related to both differences in spray nozzle flow rates and calibration errors may predispose the crop to a greater risk of phytotoxicity in overdose sites, when if it is a phytosanitary product, such as requiring early reapplications in under-dose sites to reduce the residual power of the products, in addition to limiting the efficiency of the agrochemical against the damage agent.

In addition to the problems mentioned, there is also the loss of the productive potential of crops due to the competitiveness of the crop with damage agents, which will be more intense the lower the efficiency of spraying in the chemical control of these agents. Therefore, there is no point in purchasing the most efficient product if the equipment used to apply it is far from ideal conditions.

This article was published in issue 145 of Cultivar Máquinas magazine. Click here to read the edition.