A comparative study of the soil solution chemistry of two Amazonian forest soils (Central Amazonia, Brazil)

Abstract

Abstract. Analyses of the chemical composition of rapidly percolating soil water were used to study the genesis of a shallow podzol in a Campinarana forest and a clayey ferralsol from a typical rainforest located in North Manaus (Amazonia, Brazil). The samples were collected in lysimeters and analysed for Ca2+, Na+, K+, NH4+, SO42-, NO3-, Fe, Si, and Al. A large percentage of the nutrients was recycled in the upper 40 centimetres of both soils. The soil water concentrations in nutrients were very similar for both environments but levels of Si, Fe and AI were higher in the podzol than in the ferralsol. In the podzolic environment, the waters were enriched in Si, Fe and AI when passing through the organic layer and the top 10 cm of the soil. The concentrations decreased between 10 and 40 cm depth due to variations in mineralogy of this soil. In the ferralsol, the Si concentrations increased considerably on reaching the soil top-horizons while small increases occurred for AI and Fe. Thermodynamic equilibrium calculations indicate that most of the dissolved AI and Fe in both soil environments were in the form of organometallic complexes and that the waters were under-saturated in respect to kaolinite and gibbsite.

Influence of soil pattern on matter transport in and from terrestrial biogeosystems—A new concept for landscape pedology

“…6, because of missing DOC data (details in Sommer, 2002). DOC mobility (compare Cornu et al, 1997) as well as lateral flow regime, because spodic B often is developed as hardened horizon (= "humuscrete", Thompson et al, 1996). If no immobilization zone is developed downslope, these soils must be the source areas for high DOC fluxes observed in black water rivers (compare data of Richey et al, 1990;Grip et al, 1994;Aitkenhead and McDowell, 2000).…”

Behaviour of chemical solutes during a storm in a rainforested headwater catchment

“…In both throughfall and overland flow, the silica and aluminium are at least partly derived from the dissolution of mineral particles. Nevertheless, it is established that these two constituents also take part in the biological cycle in tropical forest, being leached from the canopy or the litter (Lucas et al, 1993;Rose et al, 1993;Alexandre et al, 1994;Cornu et al, 1997). Lorieri and Elsenbeer (1997) noted relatively high Al contents in the overland flow under tropical forest.…”

Fluxes of dissolved organic carbon in two tropical forest ecosystems of East Kalimantan, Indonesia

“…ferralitization) may be less than in boreal and temperate soils. The higher concentrations of DOC do occur in the tropical regions, however (Jamet et al, 1996;Cornu et al, 1997). It seems likely that the roles of DOC in tropical forests may vary with vegetation and soil types.…”

“…The concentrations of DOC are less in Oxisols of tropical regions (Cornu et al, 1997;Schwendenmann and Veldkamp, 2005). Therefore, the contribution of DOC leaching to SOC cycle and pedogenesis (e.g.…”