Reversing land management from no tillage to conventional tillage (tillage reversal) to deal with weed infestation and accumulation of crop residue in long-term no tillage systems may dramatically alter soil carbon (C) dynamics. We studied the impact of nitrogen (N) fertilization and tillage reversal on the quantity and quality of water-extractable organic C (WEOC) and N (WEON) in the 0-10cm soil layer in two contrasting soil types located at Ellerslie (high organic matter content) and Breton (low organic matter content) in central Alberta, Canada. We used a split-plot design with N assigned to the main plot and tillage to the subplot. Each treatment had two levels which included addition of 0 (N0) vs. 100kgNha-1yr-1 (N100) N fertilizer and long-term no tillage (NT) vs. tillage reversal (TR); straw was retained on site in all treatments as part of the management regime. Our results showed that soil organic C and N storage were not affected by long-term N fertilization or tillage reversal at Ellerslie but were increased at Breton. Soil WEOC was significantly higher under N100 than under N0 at both sites. Soil WEOC was TR
