Efforts to sequester atmospheric carbon in soil require effective monitoring methods. Soil water content confounds the conventional application of infrared absorption. Raman spectroscopy contends well with water, but suffers from the overwhelming fluorescence typically encountered in the analysis of soil samples. Here we
propose to combine an modulated two-colour illumination scheme with antiphase lock-in detection that will serve to suppress fluorescent backgrounds and uncover Raman signatures of organic substances captured in soils.