Contrasting approaches for estimating soil carbon changes in Amazon and Cerrado biomes - Maia, Stoécio Malta Ferreira; Carvalho, João Luis Nunes; Cerri, Carlos Eduardo Pellegrino; Lal, Rattan; Bernoux, Martial; Galdos, Marcelo Valadares; Cerri, Carlos Clemente (Soil & Tillage Research, 2013)