Abstract

The statistical process control applied in the irrigation systems allows the visualization of process to reduce wastage of inputs, such as water and energy quality, which contributes to assessing its proper functioning, and feasibility of implementation and operation. That is why it is necessary to evaluate the self-compensating emitters using saline water at different concentrations. This experiment was applied in the greenhouse, agricultural engineering academic unit, Federal University of Campina Grande. The treatments consisted of five salinity levels of irrigation water (ECwi) (0.6, 1.5, 2.5, 3.5 and 4.5 dS m^-1 at 25°C), set in pressure of 160 kPa during 15 irrigation  trials for new  emitters, with 350 h of operation. The use of statistical process control tool has shown promise in identifying emitters’ problems due to the use of lower quality water for irrigation. The inferior quality of water does not influence the flow and Christiansen uniformity coefficient of self-compensating emitters, but after 350 h of operation, there is need management operations and maintenance of the system to be made. The uniformity coefficient Christiansen (CUC) for new and used emitters above 90% was rated as excellent in all treatments saline. The Shewhart control charts allowed diagnosing of about 350 h of operation which is necessary for the maintenance of the irrigation system when operating with saline water.

Key words: Quality engineering, Shewhart charts, electrical conductivity.