Ž . Geoderma 99 2001 245–260 www.elsevier.nlrlocatergeoderma Decomposition of maize straw in three European soils as revealed by DRIFT spectra of soil particle fractions R. Spaccini a , A. Piccolo a, ) , G. Haberhauer b , M. Stemmer b , M.H. Gerzabek b a Dipartimento di Scienze Chimico-Agrarie, UniÕersita di Napoli A Federico II B ` 80055 Portici, Italy b Austrian Research Centre Seibersdorf, Department of EnÕironmental Research, 2444 Seibersdorf, Austria Received 1 June 1999; accepted 22 June 2000 Abstract Ž . Diffuse Reflectance Infrared Fourier Transform DRIFT technique was used to investigate decomposition of maize straw residues in particle-size fractions of three European soils in a 1-year incubation experiment that simulated both incorporation and mulching practices. The aliphatic bands in the 2920–2860 cm y1 regions were used to derive decomposition curves and mineraliza- tion rates of maize residues. Evaluation of soil organic matter changes by DRIFT in particle-size fractions depended on soil texture and soil aggregate stability. Decomposition could be followed over the full incubation period only in three size-fractions of the silty German soil because of its intermediate aggregate stability. DRIFT spectra were not useful in the least stable sandy Danish soil and in the most stable clayey Italian soil. Decomposition 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 or particle-size fractions in some soils provided that adequate soil dispersion is obtained. q 2001 Elsevier Science B.V. All rights reserved. Keywords: DRIFT spectroscopy; soil organic matter; decomposition; particle-sizes; fractionation; sonication ) Corresponding author. Fax: q 39-081-7755130. Ž . E-mail address: alpiccol@unina.it A. Piccolo . 0016-7061r01r$ - see front matter q 2001 Elsevier Science B.V. All rights reserved. Ž . PII: S0016-7061 00 00073-2