Landscape position and land use effects on nitrogen and phosphorus cycling within a riparian-agricultural system in cental Alberta

The objective of this study was to examine the effects of landscape position (forage upland vs. forage riparian) or land use (native vegetation riparian vs. forage riparian) on rates of (a) phosphorus mineralization, (b) nitrogen mineralization/nitrification and (c) denitrification within an agricultural system in central Alberta. Phosphorus and nitrogen mineralization followed a seasonal pattern of net immobilization during the winter to net mineralization throughout the growing season ranging from an average of -0.06 kg P ha -1 d-1 in the winter to 2.54 kg P ha-1 d-1 in August 2006 for P and 0.06 kg N ha-1 d-1 in the winter to 0.88 kg N ha-1 d -1 in June 2006 for N. The denitrification rates were higher during spring snowmelt especially in the forage riparian treatment (485 mug N 2O-N m-2 d-1) compared with either the forage upland (222 mug N2O-N m-2 d -1) or the native vegetation riparian (129 mug N2O-N m-2 d-1) treatments.