The sprayer boom is a large and complex structure, used to support the spray nozzles. It is important to control and minimize the vibration of the structure on the vertical and horizontal planes, in order to insure the uniformity of pulverization over the field. Owing to the large spray boom widths, flexible behaviour of spray booms becomes important. Even small deformations of the structure can cause, by the large spray boom width, considerable displacements at the boom tips. However, there is not a clear correlation between the boom width and the amount of the spray boom motion. Another important factor is whether it concerns a trailed or a mounted sprayer. As spray boom motions play a dominant role on the spray distribution pattern, spray boom stability is important. Theoretical studies, simulations and field experiments have indicated that due to the spray boom vibrations, spray deposit distribution varies between 0 and 80 %. In this paper the static and dynamic study of a sprayer boom structure of about 24 m length is presented. Starting from the CAD model of the sprayer boom structure, a standard mesh procedure as a preprocessing step of a finite element analysis has been followed. Mainly shells, a reduced number of solid elements and rigid connection elements were used. The purpose of the static linear analysis was to determine the state of tension and deformation that develop in the boom during its exploitation. The geometric model made for the linear static analysis using the finite element method comprises several steps and highlights the mechanical response of the structure. An important parameter of the dynamic behaviour is the boom vibration amplitude. This parameter was observed in the finite element analysis of the boom structure considered at a natural scale. Other similar parameters, such as the resonant frequencies, have been observed.

Agroinoculants are alternative products for the agrochemical products, their use reduces environmental pollution and contamination of food. The equipment for microbial inoculants application is designed to the modern technology of sowing and inoculating hoeing plants and vegetables, being used to apply a targeted suspension of bacteria inoculated in the best area for rhizosphere colonization for improve plants nutrition, protection, stimulation and soil structure. This paper presents the results obtained at the tests accomplished in laboratory conditions of the equipment for microbial inoculants application INOC, which has been designed, realized and tested at INMA Bucharest. Performing the laboratory tests it have been determined following qualitative working index: pump debit, nozzles debit, substance norms, stirring system efficiency.

In this paper, sowing rate optimization of grassland drills consisted in finding an optimum combination between the seed flow of the seed metering device and the drill working speed, in order to achieve the sowing rates required by agro-technique for herbs seeds. It was developed a mathematical model that describes the seed flow variation depending on the working speed of the grassland drill and the active length of the groove cylinders. The experimental research was conducted using a grassland drill with eight metering devices and an automated installation, which simulates the working speed of the drill, collects and weighs seeds from each individual metering device. By using MathCad 14.0, it have been drawn the variation diagram of seed flow depending on active length of the groove and working speed. The comparative study of the variation diagrams based on experimental data and the variation diagrams obtained from mathematical modelling highlighted that the downward trend of the seed flow was observed in 66,67% of the results. Based on the mathematical model presented in this paper, it might be developed an algorithm enabling for fast obtain the optimal combination between the adjustment parameters, in order to apply a desired sowing rate.

The article presents the process by which, with the help of 3D printing technology, the piston of the differential injection device was produced using ABS material. It was made with fused filament fabrication (FFF) technology, and the smoothing process was used to improve the surface quality. The piston is part of a complex equipment for underground fertilization of agricultural crops.

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