SOIL MICROBIAL BIOMASS-C AND MATHEMATICAL-MODEL FOR TOPSOIL MICROBIALEVALUATION

The methodological procedure ''Bioindication of soil fertility'' compr ising a mathematical model for topsoil microbial evaluation was used i n investigation of a wide range of localities in the territory of the Czech Republic in the years 1990 to 1994 with an aim to assess the imp act of anthropogenic activity on the topsoil environment. As indicator s for defining the quality of soil environment and the effect of anthr opogenic activities on soil environment, the following values were cho sen: the values MB-C (microbial biomass-C), above all expressed in per centage to the model-calculated minimum and the values EX-C (extracell ular extractable organic-C), including percentage to the model-calcula ted maximum. The above procedure had confirmed the high quality of soi ls in the foothill region of Orlicke hory (Eastern Bohemia; 108 to 145 % of model minimum), especially stagno-gleyic cambisols in the microre gion Cervena Voda-Kraliky, followed by albic and orthic luvisols and r endzinas in protected landscape regions of Krivoklatsko and Cesky kras (Central Bohemia; 88 to 99% of model minimum). Within the long-term p olyfactorial experiment conducted at Humpolec (Southern Bohemia) a pos itive effect of double rates of manure and calcium materials applied i n three to five year interval (90 to 92% of model minimum; unfertilize d control 66%) has been confirmed. In addition, a high sensitivity of the values EX-C on the impact of anthropogenic activity on the topsoil environment was confirmed.