Controle de qualidade de irrigação e fertirrigação por gotejamento em horta urbana

Abstract

The drip irrigation system stands out among other irrigation methods because of its high efficiency and uniformity. One of the advantages of the drip system is that pressurizing the system can be performed by gravity, avoiding costs with energy and equipment. In urban gardens, one should expect small irrigation systems and little technology involved; still, however simple it may be, the system must have a good uniformity of application. Thus, the objective of this work was to verify the uniformity of the system under different hydraulic loads using quality control tools. The experiment was carried out in an urban garden of the municipality of Cascavel, PR. The dripping tube used was of the brand Siplast, model P1. The uniformity of the system was evaluated by the method of Keller & Karmeli (1975), using irrigation and fertigation under hydraulic loads of 1.20, 1.40, 1.60, and 1.80 mca. The CUD, CUC, CUE, and CV were calculated and classified to verify uniformity. The quality control tools used were the Shewhart Individual, MMEP, and CUSUM control charts, as well as the process capability index. Regression analyzes were also performed, to know the effect of the change of hydraulic load on the flow and the uniformity of the system. In all regression analyzes, the fittest model was the exponential, and the higher the hydraulic load, the higher the system flow and uniformity. In all the cases studied, the different coefficients of uniformity were classified as excellent, and the coefficient of variation as low. The excellent uniformity of application was further confirmed by the control charts and process capability indices, which in all cases classified the uniformity of the system as adequate. The individual Shewhart control chart was less sensitive to possible changes, while the MMEP and CUSUM charts were more accurate, the latter being more sensitive to variation.