Sumner's Legacy: Intelligent Tropical Agriculture in Brazil.

Malcolm Sumner’s greatest impacts on tropical soils science were on aluminum saturation and gypsum applications in acid soils. Both have had enormous consequences on the most successful example of intelligent tropical agriculture in the Cerrado of Brazil. The co-discovery (independently with Eugene Kamprath’s)  of   Al saturation as the best metric for liming needs permitted liming to pH 5.5 as the practical approach in much of the 14 million hectares of cropland in the Cerrado, avoiding the fallacy of liming to pH 7. The use of gypsum to move Ca down the subsoil to promote deep root development is now widely practiced in Brazil. A new system—integrated crop-livestock (integraҫão lavoura- pecuária) combine the correction of the soil profile to low levels of Al saturation and sufficient  available Ca, which is paid for by crops and then enable steers to gain weight during the dry season without irrigation, by the pasture roots utilizing subsoil moisture. This system is  really intelligent tropical agriculture.