Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/1996
Publication Date: N/A
Technical Abstract: Liquid sewage sludge from local wastewater treatment plants was applied to a 16-ha terraced watershed in Minnesota over a 20-yr span. Sludge-amended and non-amended soils and selected freeze-dried sludge samples were exhaustively extracted with 0.1M Na4P2O7/NaOH under N2. Humic acids (HAs) and fulvic acids (FAs) were isolated from the extracts using a modified IHSS procedure. Characterization included: yield, elemental composition, CEC, sugar and amino acid contents, and fluorescence, FTIR, and NMR spectra. The soil HAs were alike in chemical composition and had aromatic structures. The sludge HAs were similar to each other, but different from the soil HAs in content and were aliphatic in structure. The FAs of soils and sludges exhibited a similar trend. The addition of sludge humic substances appeared to have little impact on the chemical composition of soil HAs and FAs.