Stone industry waste and Biochar as an Element of the Circular Economy: Application in Soil Regeneration and Fertilization

MINIATURA 9

Funding Organization: National Science Centre

Project title: Stone industry waste and Biochar as an Element of the Circular Economy: Application in Soil Regeneration and Fertilization

Agreement number: DEC-2025/09/X/ST10/00808

Project implementation period: 01.12.2025 – 30.11.2026

Principal Investigator: dr Justyna Szerement

Project value: 49 851,00 PLN

Funds granted for Lublin University of Technology: 49 851,00 PLN

Abstract: The stone processing industry in Poland (granite and marble processing) generates approximately 60–150 thousand tonnes of waste annually. Some of this waste is landfilled or used as construction aggregate; however, due to its high content of micro- and macronutrients, it may also find applications in agriculture, horticulture and land reclamation. A particularly interesting material is stone slurry produced at the final stage of stone processing, which after drying forms a fine mineral fraction. Available studies suggest that stone industry waste may serve as an alternative to traditional liming materials or as a fertilizer additive; however, knowledge regarding its effects on the physicochemical and biochemical properties of soils remains limited. A novel aspect of the proposed research is combined use of stone slurry and biochar. Mineral materials may increase soil nutrient availability, while biochar may promote carbon and water accumulation and improve the physical, chemical and enzymatic properties of soils. The application of these amendments is consistent with the concept of the circular economy and directly addresses research problems within the discipline of environmental engineering, mining and energy, addressing issues related to waste management and soil protection.The aim of the study is to determine the effects of stone industry waste, biochar and their mixture on the changes in physicochemical and biochemical properties of degraded soil. It is expected that the application of these amendments will reduce soil acidity, increase nutrient availability and enhance soil enzymatic activity. Conducting the experiment at several time points will allow assessment of the rate and intensity of changes in the investigated soil properties.
A laboratory incubation experiment will be carried out using soil characterized by low pH and low nutrient content. Stone slurry will be obtained from a facility processing tombstone slabs, while biochar will be produced from the pyrolysis of hardwood residues at 500°C. The experiment will include four treatments: control soil, biochar (30 t/ha), stone slurry (10 t/ha), and a mixture of both amendments. Analyses will be performed after 1, 7, 30 and 60 days of incubation.
The scope of the study will include measurements of soil pH, EC, TOC, DOC, dissolved nitrogen content, macro- and micronutrient content, exchangeable base cations, hydrolytic acidity, and soil enzymatic activity. The obtained physicochemical data will be correlated with the enzymatic activity of the investigated soils over the incubation period.