ABSTRACT
The operation of drip lateral lines is affected by the topography of the irrigated area and represent, depending on the type of water applied, changes in the discharge characteristics of the emitters. The research had as objective to evaluate the hydraulic performance of built-in labyrinth drippers, non-pressure compensating, with different waters and slopes of the lateral lines. The experiment was carried out on a test bench and consisted of a randomized block design with split-plots: first factor with four types of water, representing the plots: clean water, water with fertilizers, cassava starch wastewater and poultry slaughterhouse wastewater; second factor with slopes of the lateral line, constituting the sub-plots: upslope, level and downslope. The experimental statistics consisted of analysis of variance with subsequent simple-effect analysis and Tukey test at 0.05 probability level to compare the means of dripper flow rates. Quality control statistics was performed using Shewhart’s control charts with interpretations based on upper and lower control limits, as well as non-random pattern recognition. Waters of inferior quality modified the flow rates of the tested drippers regardless of the variation of internal pressure caused by the slope of the lateral line. Water with fertilizer (300 mg L-1) obtained the best conditions of temporal irrigation quality verified by the control charts. Irrigation with poultry slaughterhouse wastewater obtained the same flow rates in all slopes. Cassava starch wastewater caused the lowest flow rates among all the waters.
Key words:
fertigation; Shewhart’s control charts; labyrinth drippers
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x - Mean flow rate (L h-1), UCL - Upper control limit, LCL - Lower control limit, black dots represent evaluations with flow rates between UCL and LCL, red dots represent evaluations with flow rates outside UCL and LCL