Calibração de sensores capacitivos e tensiômetros em diferentes tipos de substratos e viabilidade do uso em manejo de irrigação de plantas ornamentais

Abstract

The objective of this work was the calibration of capacitive sensors (models, EC-5 and 5TE), and tensiometers in different substrates and analysis of the viability of the irrigation management of the cultivar Pimenta Iracema Biquinho, grown in a greenhouse. The calibration of capacitive sensor models, EC-5 and 5TE and tensiometers were conducted in the hydraulic laboratory of the Federal University of Pampa-Campus, Alegrete / RS. Carolina Soil® soil and substrate calibration are used for calibration. Different mixtures were tested, being these: T1 (100% substrate); T2 (100% Solo); T3 (90% soil + 10% substrate); T4 (80% soil + 20% substrate); T5 (70% only + 30% substrate); T6 (60% only + 40% substrate); T7 (50% soil + 50% substrate), T8 (40% soil + 50% substrate); T9 (30% soil + 70% substrate) and T10 (20% soil + 80% substrate) in order to verify its feasibility of use in more porous materials. The sensors and tensiometers were installed in plastic vessels with a diameter of 0.3 m, height of 0.2 m and capacity of 2.6 L. Where weighings of the set (container containing soil, sensors and tensiometers) and daily data readings were performed sensors and tensiometers. After the calibration was finalized, the soil water mass, soil volumetric moisture and soil volume were determined in each vessel. The experiment was conducted in greenhouse, located in the experimental area of the Agricultural Engineering course, Federal University of Pampa - Campus Alegrete / RS. The experimental design was a completely randomized 4x3 bifatorial, with twelve treatments and four replicates in each, totalizing 48 experimental units. Being the substrate type factors and irrigation rates. The seeds of Pimenta Iracema Biquinho were seeded in styrofoam trays with their cells filled with commercial substrate. After the seedlings were transplanted to plastic containers with capacity of 2.6 L, filled with mixtures of soil with commercial substrate. Throughout the experiment were evaluated the viability of the use of sensors in the management of Pimenta, through observation of the growth and development of the crop. The tensiometers were efficient to characterize the water retention curve in all substrates tested. The calibration curves obtained for the capacitive sensors on the different substrates presented high values of determination coefficient (r2), indicating that, when properly calibrated, they can be used with good results in the determination of the moisture of the substrates.