Meadow plant litter species diversity – impact on organic matter accumulation.

We evaluated the effect of plant litter species diversity on the on humus accumulation in the underlying substratum and on soil microbial communities composition in experimental field study.. Sandy loam (sand mixed with loam) mesocosms of were examined over the course of 2.5 years. Plots contained simplified substratum –. Five litters composed of meadow plants; both grasses and herbs (weed species) were used. Litters were composed of single species (I - Dactylis glomerata, II - Festuca rubra and III - Trifolium pratense) or were species mixtures IV (mixture of 3 species I, II and III); V (mixture of 12 species - IV and 9 other grasses and meadow weeds). Results baased mainly on the last year of the experiment show that most of the differences among treatments found in the substratum below the litter cover resulted from the litter diversity. Soil respiration, microbial biomass and numbers of fungi and bacteria did not differentiate between mono- and multispecies treatments. Despite of that the soil respiration and algal biomass were significantly correlated during the study period. The biomass of algae as well as carbon and nitrogen increases in the substratum, depended on the litter diversity and were higher when litter composition was more complicated. In general, our results suggest that algae may participate in the process of humus formation...