Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/1998
Publication Date: N/A
Interpretive Summary: In the Ozarks, soil properties change as you move from the ridge tops to the valley bottoms. Some of these changes are due to the types of rocks beneath the soils or the type of vegetation (grass or trees) that grew on the soil before it was farmed or logged. Since World War II, increased poultry production in the area has resulted in repeated applications of poultry litter to most pasture lands. There is now concern that phosphoru levels have built up in soils of the Ozarks to the point that too much phosphorus is dissolved in runoff during rainstorms causing algal and weed growth in lakes and streams. This study measured several properties of soils at a site adjacent to the Illinois river. The results indicate that the forest soil nearest the river may be able to absorb nutrients transported in runoff from the surrounding uplands. This finding has implications for advising growers on which soils poultry litter may be safely applied.
Technical Abstract: Surface runoff of nutrients after land application of animal manures is influenced by climate, physical and chemical properties of the soil, and land use. The objective of this study was to characterize the surface soil properties along a toposequence from a riparian forest to a grazed ridge top at a site in the Ozark Highlands. Sampling transects (60 m long) were established in five soil mapping 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 measurements were also completed on four of the transects. Soil test phosphorus and percent 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. All soils had similar silt content (range = 67.2-73.9% but the riparian forest soil (Razort silt loam) had more clay and significantly less sand and coarse fragments. The Razort soil also had higher cation exchange capacity (5.14 cmol kg**-1) and infiltration rate (5.29 cm h**-1) suggesting that the riparian forest may act as a nutrient sink in this landscape. Results of this study will be combined with forage production and hydrogeologic analyses to develop best management practices for poultry litter applications and to provide baseline data for the assessment of poultry litter effects on soil properties.