Microbial characteristics, carbon and nitrogen content in cambisols and luvisols

Tested soils (1991-2002) were defined by chemical, textural and microbial characteristics. From the tests which describe cambisols, the following parameters have to be stressed. The higher level of Corg (1.20-1.76%), which resulted in quite high microbial biomass carbon content (396-625 µg/g dry soil), high control respiration (0.45-0.80 mg CO2/h/100 g dry soil) and potential nitrification with (NH4)2SO4 (6.7-18.4 mg N-NO3/8 days/100 g dry soil). Studied luvisols reached typical levels: Corg (0.97-1.22%), CMB (398-503 µg/g dry soil), control respiration (0.46-0.57 mg CO2/h/100 g dry soil), potential nitrification with (NH4)2SO4 (3.2-9.9 mg N-NO3/8 days/100 g dry soil). Lower levels of organic carbon and a medium level of microbial biomass raised in higher ratio CMB/Corg (average 4.0%). Highly significant differences (p < 0.01) between cambisols and luvisols were determined for Corg, Nt, pH(KCl), CMB, CMB/Corg, CE, control respiration and potential nitrification, while the difference in potential ammonification with peptone was at level p < 0.05. With the exemption of ratio CMB/Corg all cambisol characteristics were higher than luvisol ones. Studied soils were evaluated by six biological criteria (CMB; ratios: CMB/Corg, CE/CMB, potential/control respiration, potential/control ammonification, potential/control nitrification). These criteria distinguished tested soils into three groups. The first one includes two localities in the mountain region (Červená Voda 809, 810; altitude 565-590 m) defined as stagnic cambisols with higher content of Corg (1.40, respective 1.76%) and simultaneously with the highest biomass of micro-organisms from all tested soils (CMB,625, respective 621 µg/g dry soil). It is not surprising that microbial activities (respiration, nitrification) at these localities were also high. The majority of the studied localities (one eutric cambisol and four luvisols) belongs to the medium group. The third group includes two localities (Neumětely - haplic luvisol, Čistá u Rakovníka - eutric cambisol) where biological criteria was mostly the worst. In the period 1993-2002 microbial biomass carbon was for both sites in the range of 357-458 µg/g dry soil which are not so bad values, but in comparison with localities in mountain wet region they are low. This status was issued in the lower ratio CMB/Corg (2.71-3.77%).