Uniformidade de vazão em mangueira gotejadora autocompensante utilizando água salina.

Abstract

The implementation of efficient irrigation systems becomes a necessity in regions where water is scarce, so the use of lower quality water is a viable alternative for irrigation besides evaluating its smooth operation, aiming at providing elements for system operation. The objective of this study was to evaluate uniformity of flow in self-compensating drip hose using different electrical conductivity (EC w) water in a twelve month period, specifically determined the coefficients Christiansen uniformity (CUC), distribution (CUD), statistical (CUE), coefficient of manufacturing variation (CVF), degree obstruction(GE), application efficiency (AE), individual Shewhart charts and process capability index in self- compensating drippers in waters of different salt concentrations. The research was conducted in a greenhouse belonging to the Academic Unit of Agricultural Engineering, Federal University of Campina Grande, latitude 07 º 13 'S, longitude 35 º 53' W and an average altitude 550 m. We used an analysis of variance in a completely randomized block with scheme factorial with five levels of electric conductivity (EC wi) (0.6, 1.5, 2.5, 3.5 and 4.5 dS m-1 a 25 ° C) end under four different operating pressures (60, 100, 140 and 160 kPa), with three replications in two consecutive crops of sunflower, totaling 60 experimental plots. For statistical quality control we used the five salinity levels of water and set the pressure in 160 kPa of 15 trials irrigation the emitters new for , with 210 and 350 hours of operation. Flow variation of self-compensating emitters were considered low analyzed over time being within the recommendation of ± 7% of the nominal flow. emitter obtained exponent values between 0.02 to 0.09, classified as self-compensating being in accordance with the manufacturer's data. The flow that is closer to that recommended by the manufacturer on new issuers occurred in pressure of 60 kPa and salinity of 0.6 dS m-1, when it increased uptime for 210 and 350 hours, the behavior was similar to new issuers. The values of the coefficients found CUC, CUD, CUE, FVC, GE and EA, were considered excellent and were not significantly influenced by the levels of salts in the irrigation water and the interaction between salinity and pressure when new, and are influenced by pressure service applied. The interaction between (S x P) influenced significantly the coefficients analyzed for evaluations carried out with 210 and 350 hours of operation, except for the CVq with 350 hours of operation. The performance was considered satisfactory emitters using saline water, the pressure of 60 kPa which resulted in better cost benefit. The Shewhart charts is a tool capable of diagnosing changes in the irrigation system showing the time to do maintenance. The emitters were considered capable when new, after 210 and 350 hours operation need of maintenance so you can keep within the limits of control making the emitter able. The process capability index is a tool to diagnose whether the irrigation system is able to keep under control, ie, whether it will be able to maintain acceptable levels of uniformity, helping the irrigator decision making.