1. Dep. of Soil ScienceNorth Dakota State Univ.FargoND58105
2. Dep. of Environ. SciencesUniv. of CaliforniaRiversideCA92521
3. Dep. of Biosystems Eng. and Environ. SciencesUniv. of TennesseeKnoxvilleTN37996–4531
4. Animal Metabolism: Agricultural Chemicals Research, Biosciences Research Lab.USDA‐ARSFargoND58105‐5674