An overview of the defects on tested field sprayers in Belgium

In Belgium, the compulsory inspection is based on the analytical principle and focuses on safety, clear and suitable measuring instruments, spray instrumentation and hydraulic equilibrium. The inspection method consists in measuring separately and independently the performances of the different parts of the sprayer (pressure gauge, nozzles, boom stability, pressure regulator, mixing of the tank, spray computer,…) to determine possible defects and to establish a precise diagnosis.
The defects noted during the diagnosis are divided into three different categories.
Category I defects are defects that automatically entail a rejection. Faults within this category must be repaired within four months and the sprayer should be submitted for retesting.
Category II defects do not result in rejection, but should be repaired by the next inspection during the inspection interval. This means that the user has three years time (= one inspection cycle) to repair these defects.
Defects of category III are only added for comment and are aimed to improve the general operation of the sprayer. The user is completely free to follow these comments.
After every three year inspection cycle, the classification of all defects is revised in a steering committee. So category II defects could end up in category I defects but also vice versa is possible.
After processing the test results of the year 2008, on only 12% of the tested sprayers a category I defect was identified. The largest number of rejections were caused by leakages (29%)followed by malfunctioning gauge (20%). Worn nozzles and a torn air bell diaphragm shared the third place (both 12%). Furthermore we find rejections for the pressure balance between the different spray boom sections (8%) and spray boom problems (9%).Those items represent about 90% of all rejections.
Concerning category II defects, small leakages and different problems with the spray boom (hinges, curvature…) are clearly causing most of the remarks (85%).
The farmers are as much as possible involved in the actual inspection and advice is given to the farmers about possible effects. All test results are registered in an official test report.
Since the start up of the inspection in Belgium, farmers became far more aware of the negative effects of a badly maintained sprayer resulting in a significant decrease of the number of rejections. Anyway, continuous information and training of farmers is still necessary to maintain or even improve the current maintenance level of the sprayers