Decomposition of maize straw in three European soils as revealed by DRIFT spectra of soil particle fractions

Diffuse Reflectance Infrared Fourier Transform (DRIFT) technique was used t o investigate decomposition of maize straw residues in particle-size fracti ons of three European soils in a 1-year incubation experiment that simulate d both incorporation and mulching practices. The aliphatic bands in the 292 0-2860 cm(-1) regions were used to derive decomposition curves and minerali zation rates of maize residues. Evaluation of soil organic matter changes b y DRIFT in particle-size fractions depended on soil texture and soil aggreg ate stability. Decomposition could be followed over the full incubation per iod only in three size-fractions of the silty German soil because of its in termediate aggregate stability. DRIFT spectra were not useful in the least stable sandy Danish soil and in the most stable clayey Italian soil. Decomp osition rates derived from DRIFT results were similar to those obtained by isotopic techniques. DRIFT spectroscopy may represent a rapid and accurate method to follow fresh organic matter degradation directly in soil matrix o r particle-size fractions in some soils provided that adequate soil dispers ion is obtained. (C) 2001 Elsevier Science B.V. All rights reserved.