CHARACTERIZING THE SURFACE-PROPERTIES OF SOILS AT VARYING LANDSCAPE POSITIONS IN THE OZARK HIGHLANDS

Surface runoff of nutrients after land application of animal manures i s influenced by climate, physical and chemical properties of the soil, and land use. The objective of this study was to characterize the sur face soil properties from a riparian forest to an adjacent ridge top a t a site in the Ozark Highlands. Sampling transects (60 m long) were e stablished in five soil map units, 7.6-cm-diameter x 10-cm-deep cores extracted at 3-m intervals, and samples analyzed to determine relevant soil physical and chemical properties. Ponded infiltration measuremen ts were also completed on four of the transects. Soil test phosphorus and phosphorus saturation ranged from 10 to 31.4 mg kg(-1) and 9.1 to 18.4%, respectively, and reflect the recent history of limited poultry litter or fertilizer application. Soil samples from each transect had similar average silt content (range 67.2-73.9%), but the soil in the riparian forest (Razort silt loam) had more clay and significantly les s sand and coarse fragments. The Razort soil also had a higher cation exchange capacity (CEC) (20.7 cmol kg(-1)) and infiltration rate (5.29 cm h(-1)). Trends in clay content, infiltration rate, and CEC suggest that the riparian forest and adjacent alluvial pasture may act as nut rient sinks in this landscape. Results of this study will be comb:comb ined with grazing management and hydrologic analyses to develop best m anagement practices for poultry litter applications and to provide bas eline data for the assessment of long-term effects of litter applicati on on soil properties. (Soil Science 1998;163:907-915).