ABSTRACT
The present study was carried out with a rotary irrigation sprinkler with the objective of quantifying the influence of rotation rate, operational pressure and oscillation period of the impact arm coupled to the sprinkler, on the spatial distribution of water, in such a way as to simulate, through production functions, the potato crop production under portable irrigation systems. The tests were conducted with the combination of three factors: operational pressure (200, 300, and 400kPa), time for a complete rotation (7, 15, 30, 60 and 90 sec.) and the adjustment level of the spring tension coupled to the impact arm (deflection angle 0°, 60°, 240° e 480°). With the coefficient of uniformity (Christiansen) and the reduction of potato yield for seven sprinkler spacings (6 x 12, 12 x 12, 12 x 15, 12 x 18, 18 x 18, 18 x 24 and 24 x 24m), a multiple range analysis based on the trust interval methodology was conducted. It was observed that the larger the time of sprinkler rotation the better the uniformity coefficient under limiting spacings recommended by the manufacturer, and setting the deflection angle of 240° (spring tension) as the maximum limit to avoid harmful interference on the spatial distribution of the water.
Key words:
irrigation; sprinklers; spacings; adjustments; uniformity