Consistency of the Threshold Phosphorus Saturation Ratio across a Wide Geographic Range of Acid Soils

B. Dari, Aberdeen Research and Extension Center, Dep. of Plant Sciences, Univ. of Idaho, Aberdeen, ID 83210; V.D. Nair and W.G. Harris, Univ. of Florida, Soil and Water Sciences Dep., Gainesville, FL 32611; A.N. Sharpley, Univ. of Arkansas, Crop, Soil and Environmental Sciences, Fayetteville, AR 72701; P. Kleinman, USDA-ARS Pasture Systems and Watershed Management Research Unit, University Park, PA 16802; and D. Franklin, Univ. of Georgia, Crop and Soil Sciences, Athens, GA 30602.