Professor Guido Ranzanni was one of the founders of SBCS in 1947 and was an active member for over 30 years. Of the 31 founding members, he was the last to pass away, in 2011, at the age of 96. He was a member of SBCS Board of Directors between the following periods: 1947-1951, 1957-1961, 1965-1969 and 1979-1983. He was vice-president of the SBCS and president of the Organizing Committee of the VII CBCS – Brazilian Congress of Soil Science, held in July 1959, in Piracicaba, and president of the Organizing Committee of the X CBCS, also held by Esalq, in July 1965. Guido Ranzani received the title of Honorary Member of the SBCS during the XXVI Brazilian Congress of Soil Science held in Rio de Janeiro, in 1997.

As President of the Latin American Society of Soil Science (SLACS), he held the II Latin American Congress, together with the X CBCS. Born in 1915, Ranzani was born in Serra Azul – SP, but was raised in Santa Rosa do Viterbo – SP. He began his professional activities at Esalq as an assistant in the Chair of Agricultural Chemistry, in 1944. In 1957 he became a full professor. While still at Esalq, he was responsible for the creation and management of the Center for Soil Studies between 1965 and 1973. He brought the models for soil analysis from the United States. He retired from Esalq in 1977. Between 1981 and 2002, he was head of the Department of Agricultural Sciences at the National Institute for Amazonian Research (INPA). He was an advisor to the Inter-American Institute of Agricultural Sciences (IICA). At Embrapa, he was a consultant and head of the Center for Agricultural Research of the Cerrados. He also worked as a visiting professor and consultant for the Foundation of the University of Tocantins.