Nitrogen transformation rates are affected by cover soil type but not coarse woody debris application in reclaimed oil sands soils

Abstract

This study was conducted to test if applying coarse woody debris (CWD) can increase nitrogen (N) transformation rates and N availability in cover soils, forest floor mineral soil mix (FMM) and peat mineral soil mix (PMM), commonly used for reclamation of open-pit oil sands mining disturbed land in northern Alberta, Canada. Mean rates of net N mineralization and nitrification rates were greater (p<0.05) in FMM than in PMM due to greater microbial and enzyme activities in FMM. Applying CWD increased gross N mineralization and nitrification rates as well as N immobilization rates, resulting in lack of difference in net N mineralization and N supply rates between near and away from CWD. Using FMM as a cover soil for land reclamation post open-pit oil sands miningis better choice relative to PMM. Applying CWD for land reclamation is recommended to create spatial variability and diverse microsites.