The influence of litter on soil hydro-physical characteristics in an area of Acuri palm in the Brazilian Pantanal

Abstract

The hydraulic properties of the soil surface strongly depend on the physical attributes of the soil and, understanding such hydro-physical soil dynamics is both economically (e.g. recharging of the water table) and ecologically (e.g. maintenance of available moisture for the vegetation) important. The objective of this work was therefore to characterize the hydro-physical characteristics of the soil in an area dominated by Acuri palms in the northern Brazilian Pantanal. Transects of 50m was delimited and two treatments with six replicates were demarcated. In one treatment, soil litter accumulated on the soil was collected monthly during a period of two years. In the other treatment, soil litter was left under natural conditions. Data were collected on: soil density, particle density, total porosity, volumetric humidity, texture, hydraulic conductivity (saturated and unsaturated) and infiltration. Soil density was higher when soil litter was absent, and had deeper layers, greater volumetric moisture and higher total porosity when soil litter was present. Infiltration rate was significantly higher in the absence of litter, probably due to the lower matrix potential when the soil is drier. Significantly, saturated hydraulic conductivity was higher in the litter treatment and had a positive correlation with volumetric moisture (0–5cm depth), indicating that soil water fluxes are enhanced by natural vegetation cover. In contrast, unsaturated hydraulic conductivity was significantly higher in the absence of litter. These results clearly demonstrate that soil litter exerts a strong influence on the hydro-physical characteristics of the soil, improving physical quality leading to greater water flow.