Resumen
The savannas located in the forest-savanna ecotone in the Venezuelan Amazon have unfertile sandy ultisols and entisols which show a very low crop production unless they are supplemented with large amounts of fertiliser. In spite of this restriction, local farmers have established long-term production systems by using low input doses of organic manure. The use of organic waste in unfertile ultisols and entisols typical of savannas have resulted in increases in organic matter content and biological activities in soils with respect to inorganic fertilised or non-fertilised natural savanna, which, in turn, may be related to increases in crop productivity. These results could be a successful and reliable soil management technique for rehabilitation of the South American savannas.