Assessing soil aggregate stability with mobile phones

A new methodology for the assessment of soil slaking using a mobile app named SLAKES was developed. The app uses an image recognition algorithm that measures the increasing area of soil aggregates immersed in water at regular intervals over a 10 minutes period. This method measures the kinetics of the slaking process and returns a continuous stability index from 0 (very stable) to higher numbers (higher than 7 as very unstable with 14 as a commonly observed maxima).

The methodology was originally presented in  Fajardo et al. (2016) using a dataset covering a great part of the agro-ecological variability of New South Wales (NSW), Australia. By 2020 the app is already present in 36 countries from 6 continents in its Android version (released in 2017) and the iPhone version is gradually reaching an increasing audience (released in December 2019).

This work presents a study made in a medium sized farm in New South Wales, Australia. Top-soil (0-10 cm) samples were surveyed and analysed by undergraduate students using the app. Different maps of soil aggregate stability were created showing evident aggregate stability geographical patterns at medium scale. The use of SLAKES has shown reliability compared with traditional methods as shown in third party scientific publications. The simplicity of SLAKES makes this app a simple yet powerful way to assess aggregate stability and shows great potential to be included in both citizen and open science educational programs.

Fajardo, M., McBratney, A.B., Field, D.J., Minasny, B., 2016. Soil slaking assessment using image recognition. Soil and Tillage Research 163, 119-129.