This publication was prepared by Alexandra Bot, FAO consultant, and José Benites, technical officer, Land and Plant Nutrition Management Service (AGLL), FAO. It is based on contributions from: Gunter Englisch, Germany; Anthony Juo of Texas A&M University, the United States of America; William Payne of the International Crops Research Institute for the Semi-arid Tropics, Sahelien Centre, Niger; Maria de Fátima Ribeiro dos Santos, Ademir Calegari and Francisco Skora Neto of Paraná State Agricultural Research Station, Brazil.
The authors would like to acknowledge the valuable comments provided by: Parviz Koohafkan, chief, AGLL; Sally Bunning, land management officer, AGLL; Juan Jimenez, consultant, AGLL; Alessandro Piccolo of the University of Naples; Francis Shaxon, consultant; Martin Bwalya of the African Conservation Tillage Network; Peter Brinn, consultant; Christian Pieri, consultant; Bob Stewart of Texas A&M University; Norman Uphoff of the Cornell International Institute for Agricultural Development; Rachid Mrabet of the Institut National de la Recherche Agronomique Centre Aridoculture, Morocco; and Kurt Steiner of the German Agency for Technical Cooperation (GTZ).
Invaluable help on draft versions of this document was provided by R. Brinkman, FAO consultant; Telmo Amado of the Federal University of Santa Maria, Brazil; and Des McGarry of Queensland Government, Australia. In the production of this publication, the authors have been assisted effectively by Lynette Chalk.