Water uptake from tropical soils

BUCCI SJ, SCHOLZ FG, GOLDSTEIN G, MEINZER FC

Simposio; 23rd New Phytologist Symposium; 2009

Tropical savannas cover about one-eighth of the global land surface and are characterized by high plant species diversity. Both, herbaceous and woody plants are adapted to frequent fires, extremely poor soils and a long dry season of about 5 months duration. Tree species tend to have deep root systems that allow them to use deep soil water sources and exhibit a large diversity also in terms of life history traits. Deciduous and brevideciduous Cerrado trees, for example, that have a dimorphic root system with both shallow and tap roots, are involved in lifting water from deeper soil layers. Despite its geographical extent, biotic richness, and vulnerability to impacts by human activities, this biome has received relatively little attention from researchers in comparison to tropical rain forests. We will examine seasonal patterns of soil water utilization in Neotropical savannas of Central Brazil (Cerrado). The effects of relative abundance of woody plants, leaf phenology and root architecture on the soil water partitioning will be shown. We will also discuss about the effects of conversion of Neotropical savannas to plantations and pastures as well as the consequences of soil fertilization on soil water use.