Uniformidade de aplicação em sistemas de irrigação por gotejamento pulsante

Abstract

The objective of this work was to investigate pulsed application in drip irrigation, evaluating the pressure and flow values using analysis of variance (ANOVA), comparing the distribution uniformity coefficient (DUC) with the Christiansen uniformity coefficient (CUC) using Shewhart control charts, and ranking the process using the process capability index. The experiment was conducted in a laboratory setting with two different systems, one with and another without self-compensating emitters. Each of these systems underwent 25 tests for each treatment, with constant pressure and pumping controlled by timers. For the test data, four different pulse times were simulated: six applications of two minutes, four applications of three minutes, two applications of six minutes, and one application of 12 minutes, for a total of eight treatments. The pressure values in the distribution line did not change with the pulse time variation for either emitter. The flow rate of the system with standard emitters remained constant with pulse application until a minimum pulse of three minutes. The flow rate of the system with self-compensating emitters remained constant regardless of the pulse time. Christiansen's coefficient of uniformity (CUC) was more sensitive in the comparison of means for the dripper system than the distribution uniformity coefficient (DUC). However, the DUC was more sensitive than the CUC in the statistical control analysis using the Shewhart control chart. The reduction in pulse times had no effect on the behavior of the irrigation system with normal standard drippers under control. All treatments with standard drippers were rated excellent for both CUC and DUC. The average of the uniformity coefficient values and the process capability index have a directly proportional behavior, with a linear regression determination coefficient of 88.9% for CUC and 89.3% for DUC. According to CUC and CUD, irrigation systems with self-compensating drippers are classified as excellent and good, respectively.