SOMnmR: An R Package for Analyzing CP MAS ¹³C NMR Spectra of Environmental Samples

Cross-polarization (CP) magic angle spinning (MAS) ¹³C NMR spectroscopy is a versatile tool for studying organic matter (OM) in soils. Despite its versatility, the extensive post-processing required—including spinning-sidebands (SSB) correction and integration—limits its broader use. We present a new open-source R package, “SOMnmR” (accessible on CRAN and GitHub), designed to quickly process a large number of spectra, correcting for SSBs if required. The package computes the relative abundance of functional groups and can also model organic matter composition using end-member compounds. We describe the package's installation and functionalities and provide examples that (a) compare the results of two different spectrometers and (b) model the results of a large CP MAS ¹³C NMR data set. Overall, the presented package is a valuable tool for the fast analysis of ¹³C NMR data sets.