Evaluation of SLAKES, a smartphone application for quantifying aggregate stability, in high-clay soils

The measurement of aggregate stability is widely used for establishing quantified soil condition ratings. These ratings can inform managers and scientists on effective soil management practices and identify regions where poor soil conditions are jeopardizing the environment and soil productivity. However, many current methods for quantifying soil conditions are complicated and time-consuming, and require specialized equipment, especially the measure of aggregate stability. SLAKES is a smartphone application created by the University of Sydney, Australia, that quantifies aggregate stability through a simple experiment. The experiment requires three pea-sized soil peds, a petri dish of water, and a smartphone running the SLAKES application. The application takes 10 min to produce an on-screen measurement of aggregate stability and a downloadable text file of the ped dissolution over time. SLAKES, along with the Cornell Wet Aggregate Stability Test, was used on seven conventional tillage, seven no-till, and eight perennial grass fields to determine whether the application showed sensitivity to different management practices. All 22 sites were on Vertisols (Typic Haplusterts). The SLAKES results showed higher significant separation of means (p < .0001) between each management type than the Cornell method, which was only able to differentiate between conventional tillage and perennial grass management at a lower significance (p = .06). SLAKES proved to be a legitimate method for quantifying aggregate stability based on slaking. With this simplified aggregate stability measurement method, rating and quantifying soil health is viable for anyone with a portable electronic device and is much less tedious than traditional lab-based methods.