Evaluation of the transformation of organic matter to humic substances in compost by coupling sec-page

Humic acids (HAs) from soil and compost at the beginning (SO) and at the en d of the stabilization process after 130 days (5130) have been fractionated by coupling size exclusion chromatography (SEC) and polyacrylamide gel ele ctrophoresis (PAGE). Preparative quantities of HA fractions (HAFs) with dif ferent molecular sizes (MSs) and exactly defined electrophoretic mobility ( EMs) have been obtained from all samples and the HAFs weight content has be en studied. A high degree of similarity in HAFs weight content between soil HA and a stabilized compost HAsS130 has been observed. Such data seem to b e reliable for monitoring the evolution of the compost organic matter to hu mic substances for their agricultural uses. (C) 2001 Elsevier Science Ltd. All rights reserved.