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Seasonal changes in the biomass and length of fine roots and their growth into ingrowth cores were measured in a chronosequence of post-mining sites represented by 6-, 16-, 22-, and 45-year-old study sites, located on spoil heaps after brown coal mining in the Sokolov coal mining district. The depth distribution of roots differed between herbs and woody species and also with succession age. At the 22-year-old site, the greatest root biomass was found in the fermentation layer (248.9 ± 113.4 g m2) and decreased with depth. In the case of herbaceous root biomass, the greatest root biomass was found in the 16-year-old site (63.7 ± 15.2 g m2), again in the fermentation layer, which decreased with depth. Overall root biomass increased with succession age, reaching its highest value in the 45-year-old site. In younger sites, the root biomass was dominated by herbs and grasses, whereas woody roots dominated in older sites. After one year, the root biomass in ingrowth cores reached up to one quarter of in situ biomass, which would suggest a low turnover rate. However, the difference between the minimum and the maximum value during the course of one year represents more than half of the mean value. Analysis of the number of arbuscules on roots of Plantago lanceolata sown in soil from all succession stages revealed extensive colonization by arbuscular mycorrhizal fungi in early succession (14.2 ± 0.3 mm root−1), decreasing with succession age, and reaching the lowest value in the 22-year-old site (2.4 ± 0.08 mm root−1) before increasing in the oldest site. Colonization of roots by ectomycorrhizal fungi increased with succession age, reaching a maximum in the 16-year-old site. In comparison with the extent of ectomycorrhizal colonization in relation to root length, the greatest length of ectomycorrhiza-colonized roots was found in the 22-year-old site; hence, the pattern was the opposite of the one observed in arbuscular mycorrhiza-colonized roots. [ABSTRACT FROM AUTHOR]

The development of plant and soil microbial communities is one of the basic preconditions for the restoration of functional ecosystems. However, nutrients are concurrently used by plants and microbes, and the dynamics of this interaction during ecosystem development have seldom been studied. The aim of our study, thus, was to describe the dynamics of nutrient availability in soil and, at the same time, the nutrient accumulation in plant and microbial biomass along an unassisted primary succession heading toward broadleaf forest. The growth of the understory plant Arrhenatherum elatius on soils originating from three (16, 22, and 45 years' old) successional stages of a post-mining area and the development of the microbial community in the presence or absence of this plant were studied in a pot experiment. Both, the plant biomass and carbon (C) in microbial biomass in intermediate and late middle successional stages were higher than those in the early stage. In soil, extractable organic C, extractable organic nitrogen (N), and inorganic N increased with proceeding succession, but Olsen phosphorus (P) peaked in the intermediate successional stage. The amounts of N and P in plant and microbial biomass increased during succession. In the late middle successional stage, the amount of P in microbial biomass exceeded that of plant bound P approximately twice, and this increase was higher in pots with plants than without. The results imply that the competition between plants and microbes for available P may increase microbial P uptake and, thus, hinder plant growth in later successional stages. [ABSTRACT FROM AUTHOR]