## 2 Materials and Methods
### Experimental Design  
The experiment was conducted in June 2021 at the Training Center for Plant Protection Techniques of the Faculty of Technical Sciences at the University of Warmnia and Mazury in Olsztyn. The experiment was conducted under laboratory conditions to maintain a stable air temperature of 25 \(\pm\) 1 \({}^{\circ}\)C and eliminate the effect of wind [26]. Each experimental variant was tested in triplicate, and the results were calculated based on the mean values of the analyzed parameters. Figure 3: Configuration and basic dimensions of diffusers on the boom of an over-row sprayer with a secondary air blower (SAB): (**a**) each diffuser is connected to two nozzles; (**b**) each diffuser is connected to one nozzle; (**c**) side view (1—diffuser; 2—nozzle). Figure 2: Diffuser spacing on the boom of an over-row sprayer with a secondary air blower (SAB); 1–5—diffuser numbers. The experiment consisted of two stages. The uniformity of the air velocity distribution in an over-row sprayer equipped with an SAB was analyzed in the first stage of the study. Airflow velocity was measured using a Smart Sonda Testo 410i vane anemometer (Testo Sp. z o.o., Pruszkow, Poland) with a measurement range of up to 30 m s\({}^{-1}\), a velocity resolution of 0.1 m s\({}^{-1}\), and \(\pm\)3% accuracy. The anemometer was placed in a holder to stabilize the sensor and it was mounted parallel to the boom at a distance of 10 cm to 50 cm (at intervals of 10 cm), measured vertically from the air outlet in each diffuser. Each series of measurements began from the axis of the outermost diffuser and the anemometer was moved 5 cm along the spray boom each time. This procedure was used to measure airflow velocity along the axis of each diffuser and at equal distances from these axes of 5, 10, 15, 20, 25, 30, 35, 40, and 45 cm (for the largest distance between diffusers). In the second stage of the experiment, the horizontal distribution of the spray liquid was analyzed in configurations that differed by the type of spray nozzle, the number of nozzles, and the nozzle position relative to the diffusers' axes of symmetry. These measurements were conducted using a portable patternator (BBtechnika, Dzierzazenko, Poland). The patternator had a length of 3.1 m and a width of 1.5 m, and the gutter width was 10 cm. The liquid flowing in each gutter was collected into 500 mL measuring cylinders (Figure 4) with 10 mL graduations. The experimental factors were as follows. 1. Constants:  
* Distance (height) between the boom of the over-row sprayer with an SAB and the patternator--50 cm;
* Working pressure--0.3 MPa. 2. Independent variables:  
* Type of nozzle--a Lechler 110-03 flat-fan nozzle and a Lechler TR 80-03C hollow-cone nozzle for viticulture and orchard crops;
* Nozzle position--one nozzle positioned along the diffuser's axis of symmetry and two nozzles positioned on both sides of the diffuser's axis of symmetry at a distance of 9 cm from that axis;
* Configuration of the spray boom--without an SAB, with an SAB and the fan operating in first gear, and with an SAB and the fan operating in second gear. The following procedure was applied to measure the horizontal spray distribution:  
* The working parameters of the sprayer were set, including the working pressure of the spray liquid, the airflow rate controlled by the fan's rotational speed (two speed settings), the height (distance) of the sprayer boom above the patternator, and the type and number of nozzles (nozzle position relative to the diffuser's axis of symmetry);  
Figure 4: Measuring cylinders collecting the spray liquid from the patternator.