Impact of drainage on hydrophobicity of fen peat-moorsh soils
2010
Szajdak, L., Polish Academy of Sciences, Poznan (Poland). Inst. for Agricultural and Forest Environment | Szatylowicz, J., Warsaw Univ. of Life Sciences (Poland). Dept. of Environmental Improvement
Investigations of the chemical and physical properties of three different peat-moorsh soils located in the Biebrza River Valley, in the north-east part of Poland, were performed. All examined soils were used as meadows. Soil samples were taken at two depths: 5-10 cm (moorsh) and 50-80 cm (peat). Total organic carbon (TOC), dissolved organic carbon (DOC), and humic acids (HA) extracted from these samples were measured. Basic physical properties such as the ash content and bulk density were also measured. Wetting behaviour of soils was quantified using water drop penetration time test and the values of the soil-water contact angle. Significant differences were observed in the concentration of TOC, DOC and properties of HA between the two investigated depths of peat and moorsh samples. The concentrations of TOC in the soils ranged from 37.2% to 45.6%. Generally, the deeper the profiles were taken, the smaller were the TOC concentrations. The concentrations of DOC in the soils ranged from 5.3% to 19.4%, and the deeper the profiles were taken, the smaller were the quantities of dissolved organic carbon and E4/E6 values. However, an increase of the depth was accompanied by a decrease in the degree of humification or an increase in the chemical maturity of HA of the investigated peat. It was shown that the examined soils can be classified as severely or strongly water-repellent because the contact angle in most cases exceeded 90 degrees. The highest correlation between WDPT (water drop penetration time) and soil properties was obtained for the relationship between WDPT and the ash content in the examined soils. Furthermore, significant correlations between bulk density and WDPT, TOC and WDPT time, organic matter and WDPT, humic acids and WDPT, absorbance E4 and WDPT, pH and the contact angle were revealed.
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