1. Dep. of Crop, Soil, and Environmental SciencesUniv. of Arkansas115 Plant Sciences BuildingFayettevilleAR72701
2. Dep. of Soil ScienceUniv. of Wisconsin1525 Observatory Dr.MadisonWI53706‐1299
3. Environmental Resources CenterUniv. of Wisconsin1450 Linden Dr.MadisonWI53706