Recent advances in the application of 13C and 15N NMR spectroscopy to soil organic matter studies

Abstract

Nuclear magnetic resonance (NMR) spectroscopy has been applied to many studies in soil science, geochemistry, and environmental science. In recent years, the study of soil organic matter (SOM) using NMR techniques has progressed rapidly. NMR spectroscopy has been used to study chemical changes of SOM during decomposition, and also of soil extract fractions such as humic acid and fulvic acid. NMR spectroscopy of soils has improved rapidly in recent years with the introduction of pre-treatment and particle-size fractionation. In addition to routine liquid- and solid-state ¹³C NMR applications, ¹⁵N NMR spectra of natural abundant samples have been reported, but ¹⁵N-enriched material is more convenient to use due to the low natural abundance of ¹⁵N. Some newly developed NMR techniques have also been utilised, such as 2-dimensional NMR spectroscopy and improved ¹H NMR techniques. These are reviewed and commented on in this paper.