Automated Soil Physical Parameter Assessment Using Smartphone and Digital Camera Imagery

Matt Aitkenhead,David Donnelly,Malcolm Coull,Richard Gwatkin

doi:10.3390/jimaging2040035

Abstract

Here we present work on using different types of soil profile imagery (topsoil profiles captured with a smartphone camera and full-profile images captured with a conventional digital camera) to estimate the structure, texture and drainage of the soil. The method is adapted from earlier work on developing smartphone apps for estimating topsoil organic matter content in Scotland and uses an existing visual soil structure assessment approach. Colour and image texture information was extracted from the imagery. This information was linked, using geolocation information derived from the smartphone GPS system or from field notes, with existing collections of topography, land cover, soil and climate data for Scotland. A neural network model was developed that was capable of estimating soil structure (on a five-point scale), soil texture (sand, silt, clay), bulk density, pH and drainage category using this information. The model is sufficiently accurate to provide estimates of these parameters from soils in the field. We discuss potential improvements to the approach and plans to integrate the model into a set of smartphone apps for estimating health and fertility indicators for Scottish soils.

Highlights

Soil structure is the term given to the arrangement of differently-sized mineral particles and organic material into larger, more complex arrangements in the soil
Our aim is to show that in the last two and a half decades technological, statistical andrather modelling the laboratory, the quantification of soil itstructure andtosoil texturesoil canstructure be achieved through developments mean that because is possible measure in the field ratherimage than analysis directlythelinked to field-based structure environmental the laboratory, quantification of soilsoil structure andassessment soil textureparameters can beand achieved through conditions
Sand percentage values were approximately evenly distributed between 0% and 80%, while silt values were skewed towards higher values

Summary

Introduction

Soil structure is the term given to the arrangement of differently-sized mineral particles and organic material into larger, more complex arrangements in the soil. Soil texture is the proportional distribution of particles of different sizes, commonly divided into sand (>50 μm), silt (2–50 μm) and clay (

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