TENSIÔMETROS ELETRÔNICOS INTEGRADOS A PLACA MICROCONTROLADORA ARDUINO NO MANEJO DA IRRIGAÇÃO DE ALFACE EM DIFERENTES POTENCIAIS MATRICIAIS CRÍTICOS E TIPOS DE SOLO

Abstract

The rational use of water in irrigation is fundamental for the conservation of water resources. Irrigation automation based on the variation of the soil matrix potential can be used as a tool for the efficient water use in irrigation. This study aimed to evaluate lettuce, cv Wanda responses to soil water potentials for irrigation controlled by electronic tensiometers. The tensiometers were integrated with an Arduino microcontroller to control an irrigation automation system. A randomized complete block design with four replications was adopted, with critical potentials of -15, -20, -25, and -30 kPa in Red Yellow Latosol and -10, -15, -20, and -25 kPa in Regolitic Neossol. At 33 days after transplanting, lettuce phenometric parameters, chlorophyll Falker index, and water use efficiency (EUA) were obtained. The automation system monitored and recorded the potentials throughout the lettuce cycle and triggered and stopped the irrigation according to the critical potentials adopted. The soil water potentials showed average variations to the critical values for starting and stopping irrigation between 1.45% and 5.50% in the Oxisol and between 2.90% and 15.50% in the Regolitic Neossol respectively. The adoption of critical potentials above -15 kPa in Neossolo significantly reduces the frequency of irrigation. The highest fresh matter weight was obtained at the matrix potential of -10 kPa in Regolitc Neossol and the highest EUA was obtained in -15 kPa in the Red Yellow Latosol.