Biogeochemical dynamics following land use change from forest to pasture in a humid tropical area (Rondônia, Brazil): a multi-element approach by means of XRF-spectroscopy - Herpin, Uwe; Cerri, Carlos Clemente; Carvalho, Maria da Conceição Santana; Markert, Bernd; Enzweiler, Jacinta; Friese, Kurt; Breulmann, Gerd (The Science of the Total Environment, 2002)