Biosolids can be blended with edaphic components to formulate customized soil mixes (Technosols), where specific nutrient levels, moisture content, and other factors are tailored to support plant growth. The aim of this work was to evaluate constructed Technosols regarding specific physical, rheological, and biochemical characteristics, as well as for their ability to meet the growth requirements of rye grass. Soil horizons A and C, and quarry waste, were examined both individually as controls and in binary combinations with biosolids, maintaining a ratio of 70:30 in a replicated pot experiment. After 35 days, half of the pots were seeded with ryegrass (Lolium perenne ssp). After 3,5 months, the following physical, chemical, and rheological properties were measured: bulk density; plastic limit; liquid limit; saturated hydraulic conductivity; aggregate stability, organic matter and total Kjeldahl nitrogen. Enzyme activities were determined using fluorogenic substrates, whereas total bacterial and fungal composition was assessed through qPCR and amplicon sequencing using respectively 16S rRNA gene and ITS gene primers. Biosolids-based Technosols exhibited soil-like behavior across various examined variables, such as aggregate stability, microbial community composition and the yield of harvested plant biomass. Changes in the physical and chemical characteristics of mixtures containing biosolids were accompanied by corresponding changes in enzyme activities, as well as by shifts in absolute bacterial and fungal abundance. Biosolid-based Technosols possess the capability to establish sustainable and effective aggregation conditions, maintaining satisfactory water retention levels, and fostering favorable microbiological and biochemical conditions to fulfill essential soil functions, including biomass production.

AimsOpencast lignite mining causes significant disturbances to the natural environment. It isn't only the plant cover that is destroyed, also the soil cover is damaged. Soils are replaced by dumps with material composition that properties differ significantly from natural soils. Reclamation of these areas is necessary.MethodsThis study presents the effect of forty-three years of agricultural reclamation involving alternating winter wheat and winter rapeseed in three fertilization treatments: 0- (without fertilization), I-NPK and II-NPK on the chemical properties of Technosols.ResultsThe investigation demonstrated that the Ap-horizon emerged in the case of I-NPK and II-NPK treatments. There was an improvement in chemical properties for the Ap-horizon as compared to 1978: soil organic carbon (SOC), total nitrogen (TN), available phosphorus (P) and potassium (K) increased. The CaCO3 decreased, and SOC/TN ratio declined, while pH and cation exchange capacity (CEC) remained unchanged. For the Technosols' surface horizon of the 0-NPK, there were also temporal increases in TN and SOC with a decrease in the SOC/TN ratio, whereas P, K, pH, CEC and CaCO3 values did not change significantly.ConclusionIn the 43-year-old post-mining Technosols, under the effect of fertilization and cultivated plants, the Ap horizon has formed, while in the non-fertilized soil the AC and CA horizons. Soil that were fertilized had significantly higher SOC, TN, P and K values in the surface horizon than minesoils without fertilization. In the subsurface horizons, the properties of minesoils were similar regardless of fertilization.