Impact of the degree of secondary transformation on acid–base properties of organic compounds in mucks

The differences in the water adsorptivity index, variable surface charge, surface dissociation constants, and the content of hydrophobic and hydrophilic bound amino acids were studied in 14 peat muck soils at various phases of the mucking process. In general, the total concentration of bound amino acids was the highest in secondary transformed mucks. The lowest content of amino acids was found in peat muck characterized by the lowest values of the water adsorption index. Among all amino acids present in soil samples, the content of neutral amino acids was the highest, whereas sulphur-containing amino acids were present at the lowest concentrations. The concentrations of β-alanine and lysine were higher in strongly and very strongly secondary transformed soils, which indicated a higher microbial biomass content in these soils. Linear correlations were found between the total amount of amino acid as well as the amount of hydrophobic amino acids and the water adsorption index. Significant relationships were also revealed among some physical and chemical properties of investigated soils. In particular, the process of secondary transformation of peat muck soils was strongly connected with water holding capacity, surface charge, and differentiation of bounded amino acids.