Indicating soil quality using urease and saccharase activity in abandoned grassland and differently managed crop fields

In order to ascertain and make a comparison of bioactivity variation during vegetation period, soil (Hapli–EpihypogleyicLuvisol (LVg-p-w-ha), Albi–EpihypogleyicLuvisol (LVg-p-w-ab), and Hapli–AlbicLuvisol (LVA-Ha)samples collected in fields of different fertilizing and farming systems: extensive (ExF), conventional (CF) and organic (OF).The aim of this study was to determine the saccharase and urease activityresponses to different land management systems and main soil quality indices such as soil genesis type, content of soil organic carbon (SOC), total nitrogen (N), and C/N ratio. The trial was comprised of eight experimental plots (three land management systems and two crops groups: legumes and gramineous). Assessed hydrolases were observed as sensitivity-able indicators suitable to evaluate parameters of soil quality. The highest decrease and the lowest rates of urease (1.13 mg NH4 +–N g-1) and saccharase (8.40 mg CG g-1 24 h-1) activities were observed in abandoned grassland soil where mineral fertilizers were not applied.Enzyme activity correlated stronger with SOC (r=0.7) or ratio C/N (r=0.6) than that with total nitrogen content (r=0.5-0.6). Significantly higher 3 year mean value of saccharase (27.00 and 12.6 mg CG g-1) and urease (5.78 and 4.16 mg NH4 +–Ng-1 24 h-1) were observed insoil under conventional and organic management in compare with abandoned grassland. Consequently, it can be concluded that enzyme activities might be responsible to the different level of soil fertilityVytauto Didžiojo universitetasŽemės ūkio akademij