Ecological-hydrothermal assessment of pyrogenic soils of cutover peatlands

Abstract

The morphology, physical and chemical properties, distribution and composition of mesofauna, hydrothermal regime, dynamics of the aeration porosity, and fertility of pyrogenically modified and soddy-pyrogenic soils of worked-out peat deposits were studied in years with different precipitation. The ash and carbonized horizons were constituents of the pyrogenic profiles of these soils. The surface ash horizons contain grains of quartz sand, ferruginous formations, and carbonates and have an alkaline reaction. The lower lying carbonized horizon is represented by thermally transformed organic matter, and it has an acid reaction and a low water-holding capacity. The studies of the hydrological regime have revealed the differences between the pyrogenically modified and soddy-pyrogenic soils and the necessity of their additional moistening. The moisture reserves in the soddy-pyrogenic-sandy soils were much lower than their optimal amount during the whole growing period, whereas, in the pyrogenically modified peat soils, they were optimal. However, the air humidity in the years when the investigations were performed did not exert any significant influence on the hydrological regime of the soils. The analysis of the temperature regime showed that spontaneous burning of the peat soils studied was impossible. Within 2–3 years after the fire, the fertility of the pyrogenically modified and soddy-pyrogenic soils was found to be somewhat higher than that of the soils long used for grass growing due to the enrichment of the organic matter with ash. Some measures are recommended for the optimization of the fertility of the pyrogenic soils.