Effects of Soil Development on Hydrological Properties and Flow Paths:
Consequences for Nutrient Losses

Kathleen Lohsel

Runoff pathways strongly influence hydrologic and biogeochemical losses and landscape evolution.  On an evolving landscape, soil development may alter hydrologic properties and thereby change through time the relative importance of various pathways.  In this talk, I explore the role of soil development with time in shaping hydrologic properties and flow paths.  I evaluate in-situ soil-water retention, unsaturated and saturated hydraulic conductivity, and flow path characteristics of a 300 year old Andisol and a 4.1 million year old Oxisol, located at the extreme ends of a soil substrate age gradient across the Hawaiian Islands, and then place these findings within the context of the chronosequence. In the second portion of my talk, I explore the consequences of these changes for nutrient losses following N additions. I suggest that differences in hydrological properties and flow paths due to soil development, rather than nutrient status, will be the dominant controls determining the residence time and routing of water and nutrients.