Tested soils (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(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 C org (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 CO 2 /h/ 100 g dry soil) and potential nitrification with (NH 4 ) 2 SO 4 (6.7-18.4 mg N-NO 3 /8 days/100 g dry soil). Studied luvisols reached typical levels: C org (0.97-1.22%), C MB (398-503 µg/g dry soil), control respiration (0.46-0.57 mg CO 2 /h/100 g dry soil), potential nitrification with (NH 4 ) 2 SO 4 (3.2-9.9 mg N-NO 3 /8 days/100 g dry soil). Lower levels of organic carbon and a medium level of microbial biomass raised in higher ratio C MB /C org (average 4.0%). Highly significant differences (p < 0.01) between cambisols and luvisols were determined for C org , N t , pH(KCl), C MB , C MB /C org , C E , control respiration and potential nitrification, while the difference in potential ammonification with peptone was at level p < 0.05. With the exemption of ratio C MB /C org all cambisol characteristics were higher than luvisol ones. Studied soils were evaluated by six biological criteria (C MB ; ratios: C MB /C org , C E /C MB , 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 C org (1.40, respective 1.76%) and simultaneously with the highest biomass of micro-organisms from all tested soils (C MB , 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 C MB /C org (2.71-3.77%).

Microbial activities and counts of microorganisms were monitored as a part of research projects at 11 localities on arable land of different soil types during the years [2002][2003][2004][2005][2006]. The counts of microorganisms (total bacteria count, actinomycetes, micromycetes, Azotobacter, oligotrophic and spore-forming bacteria) and microbial activities (respiration, ammonification and nitrification tests) were evaluated using summary statistics, analysis of variance and correlation coefficients. The average counts of microorganisms corresponded with usual counts of microbes in arable soils. There were only some differences among localities in Azotobacter counts. Soil respiration is very often used as an indicator of soil microflora activity. Average values of basal respiration were slightly lower (0.45 mg CO 2 /h per 100 g dry soil) than usual values, potential respiration with glucose (G) or with ammonium and G (NG) responded to usual values (average G 4.27, NG 9.53 mg CO 2 /h per 100 g dry soil). All activities (except actual ammonification) were higher in spring season, but the differences were not significant. There were significant differences in correlation coefficients among the selected criteria; 66% from the total number of correlation coefficients were non-significant, 34% were significant (13% of them was at the significance level 0.05, 10% P < 0.01, and 11% P < 0.001).

During the years 19982000 soil chemical (C org , N t , pH), textural (sand, silt clay) and microbiological (microbial biomass carbon C MB , microbial extracellular carbon C EX , respiration, ammonification, nitrification) characteristics were tested on grassed chernozem [mollisol] after arable land setting-aside. Different harvest management was also tested: black and green fallow, one or two mulching per year, three cuts with plant biomass removal. For the evaluation of the influence of management and plants we have used three main criteria: (1) µg C MB /g dry soil, (2) ratio C MB /C org (%), (3) µg C EX /mg C MB or eight criteria respectively: (4) ratio of measured and model values of C MB , (5) ratio of measured and model values of C EX /C MB , (6) potential respiration with glucose, (7) potential ammonification with peptone and (8) potential nitrification with (NH 4 ) 2 SO 4 . According to these criteria, the best harvest management after arable land setting-aside from 5 different systems, which were tested, could be based on one or two mulching per year. It could be stressed that the two mulching was evaluated as the best in sum of dry mass yield (27.5 for mixtures, 20.1 for legumes and 14.2 for grasses in t/ha/3 years).

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