Carbon/Nitrogen Status Including Protease Activities of Arctic Soils Associated with Shrubs of Varying Height around Toolik Field Station, Alaska 2009.

Organic and mineral soil cores were collected from 18 transects differentiated by shrub height into three replica groups: high (average 64 cm ± SE 1.01); medium (39 ± SE 1); and low (18 ± SE 0.4); and percent plant functional group cover. Replica sample cores were taken from each transect, and after homogenization and K2SO4 extraction, if required, samples were analyzed for % C (carbon) and N (nitrogen); non-purgeable organic C (NPOC); total N (TN); dissolved inorganic and organic N (DIN, DON); microbial biomass C (MB-C) and N (MB-N). As a measure of N status, protease activity (native and potential) was determined together with total free amino acids and total soluble protein. Bulk density and pH values were also measured. K2SO4 extracted samples from a three-month incubation were analyzed as above and net mineralization was assessed.