A 30 m long experimental center-pivot was used for field tests. The sprinkler package was sized to simulate the end spans of larger machines with low-pressure spray sprinklers. The sprinklers were mounted on the drop-pipes of the center-pivot, 1.2 m above the ground. Sprinklers used in this study and corresponding operating pressures, nozzle sizes, flow rates and sprinkler wetted diameters are listed in Table 2. The R3000 sprinklers (Nelson Irrigation Corp., Walla Walla, WA) used rotating plates with grooves to break-up the nozzle jet and create discrete streams of water leaving the plate
edge. The R3000 sprinkler with the red-plate had six grooves of equal trajectory angle (12◦) and width. R3000 sprinkler with the orange-plate had eight grooves with multiple trajectories angles and widths. This type of sprinklers is currently used on low pressure center-pivot sprinkler irrigation systems.