This study was conducted to investigate the effect of slope position on amidohydrolase (urease, L-glutaminase and L-asparaginase) activities, kinetic and thermodynamic parameters of L-glutaminase. Also, abundances of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in soil aggregates of different slope positions were quantified by real-time PCR. Besides, the effects of slope aspect and position on microbial biomass C (MBC) and hydrolytic enzyme activities in soil were investigated. In each slope position, amidohydrolase activities decreased as the size of aggregate decreased. Considering the mass fraction of each aggregate Keywords : Amidohydrolase activity, kinetic and thermodynamic parameters, ammonia-oxidizing bacteria, ammonia-oxidizing archaea, slope position
