Hydrophobic and hydrophilic properties of humic acids from soils under shelterbelts of different ages

摘要

A comparative investigation of the hydrophobic-hydrophilic properties of humic acids (HA) extracted with 0.1 M Na4P2O7 at pH 7 from soils under shelterbelts of different ages [14 years old (young) and 200 years old (old)] and adjoining cultivated fields was carried out with the application of ~(13)C NMR spectroscopy and hydrophobic interaction chromatography (HIC). The results determined using both methods were in line with the chemical composition of HA. Shelterbelt age was shown to be the principal factor affecting the composition and hydrophobic-hydrophilic properties of HA. HA from soil under the young shelterbelt was found to be less chemically mature and more hydrophilic than HA from the soil of the adjoining cultivated field. By contrast, HA from soil under the old shelterbelt was considerably more chemically mature and hydrophobic than that of the corresponding cultivated field and HA from the soil under the young shelterbelt.