Effect of smart phone cameras on color-based prediction of soil organic matter content

•Smart phone photos show excellent ability to predict SOM content under ideal lighting and soil preparation conditions.•Differences in the spectral response of phone cameras have an impact on color measurement results.•The correlation between soil color and SOM content is influenced by color measurement results.•The photo-based SOM content prediction model shows poor shared capacity.•There are some potential ways to enhance the shared capacity of prediction models.