13C-CPMAS-NMR is used in the following papers:

FT-IR was used in this paper:

Interesting attached files.

Thanks Irene Fernandez for your nice sharing articles and Thanks Suresh K Malhotra

Dr. Kubar, you may use reflection spectroscopy or FTIR-AR Spectroscopic data for directly map the SOC which minimizing analytical cost and time. Please go through the publication by Rial et al. (2015). A novel approach to map soil organic carbon content using Spectroscopic and Environmental data, Procedia Environmental Sciences 27: 49-52.

Thanks Dr. J.C.Tarafdar for your nice suggestions and sharing a good reach article.

Nic ediscussion ..very informative indeed...

Spectroscopic Determination of Soil Organic Carbon and Total Nitrogen Content in Pasture Soils by  ZHENGGUO SUN, YONG ZHANG, JIANLONG LI, AND WEI ZHOU published in Communications in Soil Science and Plant Analysis, 45:1037–1048, 2014(DOI: 10.1080/00103624.2014.88362)..

Abstract : To explore a convenient and efficient approach for determining the content of soil organic carbon (SOC) and total nitrogen (TN), this study focused on capturing the features value of SOC and TN by applying the method of wavelet analysis and wavelettransformation. The soil used in the study was sampled from the pastures in Fukang Cityof Xinjiang Uygur Autonomous Region, China. The soil samples were tested by using a combined approach of chemical analysis and spectroscopy measurements. It was foundthat reflectance at 400–2500 nm was more strongly correlated to SOC than to TN. The maximum negative r values between reflectance and SOC + TN at 2309 nm was –0.81 (P < 0.01), and SOC/TN at 1693 was –0.48 (P < 0.05). The maximum correlation coefficient between SOC, TN, and wavelet coefficient was more than 0.96 comparedto the relationship among SOC, TN, and spectral reflectance. By using continuous wavelet transformation (CWT), it was found that the maximum correlation coefficientswere 0.981 at 2328 nm of scale 13 for SOC and 0.968 at 1741 nm of scale 6 for TN.These results also suggested that wavelet analysis was a better method for capturing the absorption features of soil properties and determining SOC and TN content.( PDF enclosed for further reading )

Thanks Anoop Kumar Srivastava very informative paper regarding the concerned question.