This study aims at developing a technique to detect differences in the type of soil organic matter (SOM) using diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy in combination with cluster analysis. Research to understand the dynamics and distribution of SOM is limited by the current techniques of fractionation and analysis which are un-standardized, time consuming, costly and irreproducible. The diffuse reflectance Fourier transform mid-infrared spectroscopy can be rapid and relatively cheap alternative of these techniques. It has a potential to be used in the characterization studies without the need of fractionation because it is sensitive to structure and composition of SOM. Samples from a long-term (>35 years) crop rotation by fertility trial taken in 2004 and 2005 will be used (N=384). Organic matter signature will be isolated from the DRIFT spectra and cluster analysis will then be applied on the isolated portion of the spectrum to group samples in different clusters based on the type of organic matter. The technique if found valid and useful will provide an excellent tool in the environmental and soil research studies where the researchers are interested in investigating if a particular management practice is producing changes in the quality of organic matter.