ARS | Publication request: Ultraviolet-visible absorptive features of water extractable and humic fractions of animal manure and compost

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 1, 2010
Publication Date: August 8, 2011
Citation: Zhang, M., He, Z. 2011. Ultraviolet-visible absorptive features of water extractable and humic fractions of animal manure and compost. In: He, Z., editor. Environmental Chemistry of Animal Manure. Nova Science Publishers. p. 61-81.

Technical Abstract: UV-vis spectroscopy is a useful tool for characterizing water extractable or humic fractions of natural organic matter (WEOM). Whereas the whole UV-visible spectra of these fractions are more or less featureless, the specific UV absorptivity at 254 and 280 nm as well as spectral E2/E3 and E4/E6 ratios have been used for characteristic parameters of dissolved organic matter fractions. Similar to other organic matter research, these spectroscopic parameters are used to describe molecular weight, aromaticity and polarity of water soluble organic matter fraction from animal manure. In addition, these parameters are also used in manure-related studies to monitor the decomposition and humification of manure, compost maturity and compost quality. In two case studies, we found that the ratio of E4/E6 is effective for showing differences in dairy manures arising from different feed sources, and in soils with different poultry litter application histories. The simulated spectral slope values from 300 to 375 nm were not statistically different between the two types of dairy manures. However, they differ in WEOM from soils with different histories of poultry litter application. Future studies in this area should emphasize optimal wavelength for simulation and spectral model evaluation.