Long-term agricultural reclamation on the chemical properties of Technosols at lignite postmining site – efficiency of winter wheat and winter rape

Aims
Opencast 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.

Methods
This 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.

Results
The 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.

Conclusion
In 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.