Automation of the measurement of time record in determining the hydraulic conductivity of saturated soil¹

Automação da medição de registro do tempo na determinação da condutividade hidráulica do solo saturado

HIGHLIGHTS:

Auto Ksat allows real-time data visualization, enabling discrepant data verification.

The created and tested system improved the precision of the measurement of soil water flux in laboratories of soil physics.

The automated system is a viable option to determine the hydraulic conductivity by the falling head method.

ABSTRACT

The objective of this study was to automate the acquisition of water travel time, as well as the computation of hydraulic conductivity of saturated soil by the falling head method, using water sensors and the Arduino platform. To automate the measurement of travel time, the Arduino Uno board was used, and two water sensors were installed at the initial (h₀) and final (h₁) heights of the water inside the core. When the water flows across the soil and the water level passes the bottom part of the initial sensor (h₀), the time recording starts; it ends when the water is absent from the final height of the second sensor (h₁). The equation for calculating the hydraulic conductivity was inserted into the algorithm so the calculation was automatic. Undisturbed soil samples were taken in a long-term no-tillage area. There were no significant differences for the time and hydraulic conductivity means between the permeameters. The coefficient of the residual mass index showed an overestimation of the time variable; thus, the automated permeameter improves the precision of time recording and saturated hydraulic conductivity estimated by the falling head method.

Key words:
Arduino; water sensors; falling head method