Fine root biomass and the associated C and nutrient pool under the alder (Alnus spp.) plantings on reclaimed technosols

Abstract

In the study we have analysed the increment of fine-root biomass (FRBI) and the associated pool of carbon and nutrients (N, S, P, K, Ca, Mg, Na) under alder plantings (Alnus incana, A. glutinosa and A. viridis) growing on technosols developed from combustion wastes and extremely poor quaternary sands excavated by sand mining. The control sites were located in natural habitats in the Bieszczady Mountains within the natural range of the occurrence of the investigated alder species. The fine root biomass depended on the type and properties of the technosols substrate but did not differ between the alder species. The highest fine root biomass (>1000 g m−2) was found in the nutrient-poor sandy soils (SS) of a former sand pit, whereas technosols formed from combustion waste was <301 g m−2, and the lowest (below 264 g m−2) was in natural soils. The results indicate an important role of fine roots in the development of the carbon and nutrient pools in technosols. This is particularly important in the case of barren sandy soils where a deficit of nutrients is balanced by an efficient circulation and release of elements in the decomposition process of dead organic matter, largely connected to the fine roots biomass.