Soil analysis is an interesting idea which we have yet to experiment with. This may be done in the future by either us or by the SCiO developer community using our SCiO DevKit.
The DevKit allows users to create and analyze their own data collections and then model and test them using our custom built SCiO Lab environment. The Mobile API including in the DevKit enables them to build their own mobile apps from the models.
In any case, SCiO can detect materials in concentrations of 1% or higher. So, if a model and an app is indeed developed for soil analysis, the concentrations of the micro-nutrients of interest must be higher than 1% in order to be detected.
(Relevant Product: SCiO DevKit)