Automated single ring infiltrometer with a low-cost microcontroller circuit

A method to automate data collection with a compact infiltrometer under constant head conditions was developed. The infiltrometer consists of a containment ring with a small quasi-constant head of water (i.e., 2–3 mm) that is controlled by a Mariotte reservoir and a data acquisition system based on the open source microcontroller platform Arduino and a differential pressure transducer. The presented design can be easily reproduced and operated. The infiltrometer was tested in a citrus orchard on a sandy loam soil. A simple methodology was applied for accurate data acquisition from the initial stage of the process and to minimize the disturbance of the soil surface. A new approach to process the data was proposed for determining an accurate cumulative infiltration curve from transducer output. The BEST algorithm by Lassabatère et al. (2006) was applied to determine the hydraulic properties of the soil. A comparison between the automated procedure and the original BEST procedure was made. Automatic data collection increases measurement speed, permits measurement at shorter time intervals, improves measurement precision, and allows for more efficient data handling and analysis. The proposed electronic data acquisition system based on the open source Arduino board has proved to be accurate and reliable, constituting a very cost effective alternative to previous proposed equipment. The very limited cost could represent a step toward a cheaper and widespread application of accurate and automated infiltration rate measurement. This infiltrometer could be used for situations where a large number of readings need to be collected.