Soil organic matter, biota and aggregation in temperate and tropical soils - Effects of no-tillage Johan Six, Christian Feller, Karolien Denef, Stephen M. Ogle, Joao Carlos de Moraes Sa and Alain Albrecht Agronomie, 22 7-8 (2002) 755-775 DOI: 10.1051/agro:2002043