A demonstration garden was designed in order to demonstrate the impact of ReSoil technology on soil quality. Experiments at the demonstration garden were designed to compare plant growth on original and remediated soil. The demonstration garden is located in the immediate vicinity of the Demonstration plant and is accessible to interested visitors.
Demonstration garden is used for research and scientific experiments by University of Ljubljana.
The garden consists of 9 raised beds filled with originally contaminated soil and ReSoil remediated soil. The soil was from the immediate surroundings of the garden and, due to the flooding of the Meža river, which deposited contaminated river sediments, it was contaminated with an average of 1734 mg/kg Pb, 3313 mg/kg Zn and 24 mg/kg Cd.
Uptake of heavy metals in plants grown on remediated soil was 5 to 14-times and 4 to 8-times lower for Pb and Cd, respectively. According to the legislation**, the concentration of Pb and Cd in plants grown on remediated soil, were below the limit values. The concentration of Pb and Cd in plants grown on contaminated soil exceeded the limit value for both metals. The results of the research have confirmed safe vegetable production on remediated soil. Results were also confirmed by laboratory extraction methods for determination of bioavailability of pollutants in soil.
Quality of the soil after remediation was intensively observed in cooperation with University of Ljubljana within a research project (ARRS J4 – 8219):
- Insignificant changes in chemical properties (pH, soil organic matter, soil N, P, Fe, Ca content) of remediated soil.
- Minor changes in soil texture and soil-water properties (mainly due to loss of soil structure and disaggregation of soil silt into clayish fractions).
- Transitional changes in soil biological properties (soil enzyme activities, microbial abundance and structure of population).
- No effect on the rate of mineralization of organic material.
- No or minor (and transitional) effects of remediation on visual plant growth, biomass, and physiological processes (photosynthesis, stomatal conductance and evapotranspiration of water).
- Concentration of Pb in edible parts of vegetables cultivated on remediated soil was significantly reduced, below the threshold value of legislation.
The demonstration garden is regularly visited by groups from educational institutions (schools, faculties …) and other interested visitors.
**Commission Regulation 1881/2006/EC, 2015/1005, 488/2014, setting maximum levels for certain contaminants in foodstuffs