NMR-STUDIES OF SOIL, SOIL ORGANIC-MATTER AND NUTRIENTS - SPECTROSCOPYAND IMAGING

A shea general review of all aspects of the NMR technique, in both the spectroscopic and imaging modes, as applied to the study of soil, is presented from a mainly technical point of view. Illustrations, in the form of spectra and images, are reproduced for whole soils, solids, s olid fractions, and liquid extracts from material in the authors' grou p. Nuclides covered are H-1, C-13, N-15, Al-27, and P-31. For solid sa mples the techniques employed include CP/MAS with and without TOSS, an d for liquid-state studies the first high field (14.1 T) examples for soils in both one and two frequency dimensions are presented. For imag ing further results from the first application of the stray field (STR AFI) technique applied to water in soil are given showing distortion-f ree images of both bound and free water. Finally, the first electron n uclear double resonance (ENDOR) and pulsed EPR results on soils will b e illustrated. This paper is a slightly expanded version of an introdu ctory talk of 35 minutes and so is not discursive. In particular the b enefits of the techniques presented to soil science are only touched o n. Other speakers present papers elsewhere in this issue which expand on particular aspects of the utility of NMR studies of soils. (C) 1997 Elsevier Science B.V.