This study is based on the work of Professor Alfredo Scheid Lopes, Emeritus Professor at the Federal University of Lavras (UFLA), Lavras, Minas Gerais, Brazil and Technical Consultant of the National Association for Fertilizers Diffusion (ANDA), São Paulo, SP, Brazil.
The study benefited from the contributions of C.A.P. Silva (ANDA), L.R.G. Guilherme (UFLA), K. Isherwood, J. Poulisse and T. van den Bergen (FAO).
The background photograph is from the FAO Mediabase (FAO/19379/R. Jones) and the other photographs were provided by B.E. van Wik (sugar cane) and J. Flémel (coffee). The source of these photographs is EcoPort (Portal to Ecology Management) and Pioneer.com Web site for soybean.
