Measuring Soil Organic Matter

Measuring the organic matter in soil by traditional methods is slow and labor intensive. Using an NIR field spectrometer for in situ measurements is faster, easier, accurate and less expensive. SPECTRAL EVOLUTION offers a wide range of field portable spectroradiometers with high resolution and sensitivity, including the SR-6500, NaturaSpec™, RS-8800, PSR+, RS-3500 and PSR-1100f.

Soil organic matter (SOM) is the basis for healthy vegetation. Soil organic matter greatly influences physical and chemical soil properties. As soil organic matter decreases, growing plants becomes increasingly difficult due to problems with fertility, water availability, compaction, erosion, parasites, diseases, and insects.

Measuring soil organic matter begins with taking a spectra of your samples using a contact probe or benchtop probe with compactor. DARWin SP Data Acquisition software controls our spectroradiometers and displays the spectra you have taken. DARWin also provides first and second derivatives for highlighting important features in your spectra. Key wavelengths for soil organic matter include 433, 587, 1380, 1431, 1929, 2200 and 2345nm. DARWin saves your spectra as ASCII files for use with analysis software such as chemometrics programs like Unscrambler from Camo Analytics. Unscrambler allows you to build, optimize and test your model. The coefficients from your model are used in the prediction engine built into our DARWin software to identify soil organic matter quantities in new samples.

A SPECTRAL EVOLUTION PSR+ field spectroradiometer being used to take a soil measurement.

An example of multiple soil scans plotted together on DARWin SP Data Acquisition software and saved as ASCII files.