Dinara Grasiela Alves

Desenvolvimento de um sistema para o controle do pH da água para microirrigação

ABSTRACT The aim of this work was to develop an electronic system for control of water pH in microirrigation. Thestudy was accomplished in the Hydraulics Laboratory of Biossystems Engineering Department, EscolaSuperior de Agricultura “Luiz de Queiroz” (ESALQ/USP). The water pH control system has a device foracid injection controlled by a solenoid valve. This valve is switched on by electric pulses from amicrocontroller. The system was evaluated for different water pH values (ranging from 6.2 to 9.2) underconstant (264 L h -1 ) and variable flow. The pH was measured immediately on system downstream, andalong the lateral line at 1, 14, 29, and 44 m from the lateral inlet, tests were also accomplished for differentintervals of time. The obtained results proved the efficiency of the system on maintaining water pH indesired range for constant and variable flow conditions. Meaningful temporal or spatial variations alonglateral irrigation line were not observed. Key words: clogging control, ions precipitation, treatment water