This work was carried out at Moreno's farm, located in Barreiras, west of Bahia State, Brazil with the objective to evaluate the performance of a center pivot of irrigation, regarding the irrigation efficiency due to climatic and hydraulic variable during three periods of the year and under two lateral line rotation speeds. The three-field test was conducted, during the year 2002, in May 12 and 18; July 27 and 28; and September 28 and 29; the center pivot was operated with 100 and 50% of maximum rotation speed. The results were analyzed considering a randomized complete block design for lateral rotation speed factor, and with time factor as a split plot on lateral rotation speed. Results showed that the operating pressure at the lateral end was lower than the recommended one allowing an irrigation water depth below the average at that place. Values of irrigation efficiency were smaller than the ones recommended in the literature (80%). The irrigation depth of water was reduced from the first to the third time of evaluation, due to climatic changes. Relative humidity and specially wind speed had more influence on the application efficiency.
Christiansen uniformity coefficient; distribution efficiency; application efficiency
