1. Centre for Ecology and Hydrology, Maclean Building, Crowmarsh Gifford,
Wallingford, U.K.
2. Department
of Crop, Soil and
Environmental Sciences, Division of Agriculture, University of Arkansas, Fayetteville, Arkansas, United States
3. Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, U.K.
4. Agricultural Research Service,
Pasture Systems and Watershed Management Research Unit, U.S. Department of Agriculture, University Park, Pennsylvania,
United States