Humic Acids Properties of the Wroclaw Chernosems and Phaeozems

摘要

This work describes the physical-chemical and chemical properties, fractional composition of humus acid and chemical and physicochemical properties of the humic acids formed in different humidity conditions of the Wroclaw black earths. The emphasis was put on the chemical properties of the humic acids from the Ap horizon. Samples from 8 profiles of the arable soils of different subtypes (proper, browned, eluviated and degraded) were analyzed. From the Ap horizon in the neighborhood of the profiles located, 5 additional samples were taken to the statistical verification of the results. The investigated profiles was include in Chernosems and Phaeozems soils groups according FAO-WRB 2006 reference. In collected soils samples following analyzes were performed: soil texture, pH in 1mol KCl . dm~(-1) , hydrolytic acidity (Hh), C total, N total, CaCO3, S total, the contents of exchangeable cations in alkaline character (Ca~(+2) , Mg~(+2) , K~+ , Na~+ ) and fractional composition of humus compounds with the Tiurin method. Humic acids extracted according to generally accepted IHSS method (Dziadowiec and Gonet) and were analyzed: elemental composition with the CHNS EA 1110 Analyser by CE Instruments. The values of the atomic rations H:C, N:C, O:C, as well as the internal oxidation degree according to the equation: ω=(2O+3N-H)/C, were calculated on the basis of the elemental composition expressed in atomic percentage points, IR spectra with the FTIR Spectrum BX spectrometer by Perkin-Elmer. IR spectra of humic acids were produced in the range 400-4000cm~(-1) , for tablets of 3mg HA w 800mg KBr, spectrometric properties in the UV-VIS. On the basis of absorbance values, determinate at the wavelengths 465nm (A_(465)) and 665mn (A_(665)) were calculated the values A_(4/6).