CHARACTERIZATION OF WATER EXTRACTS OF 2 MANURES AND THEIR ADSORPTION ON SOILS

To uncover possible chemical differences between stockpiled and compos ted dairy manures, water extracts of these manures were analyzed by C- 13 nuclear magnetic resonance (NMR) and by pyrolysis-field ionization mass spectrometry (Py-FIMS). Judging from the C-13 NMR, which took int o consideration all of the organic C present, aliphatic and aromatic C in the composted and stockpiled manure extracts were similar but the composted manure extract appeared to be richer in protein C, phenolic C, and carboxylic C and poorer in carbohydrate C than the stockpiled m anure extract. Major components of the extract of the stockpiled manur e extract determined by Py-FIMS, which measured only volatile organics , were N compounds > phenols + monolignins > carbohydrates > alkylarom atics > peptides = lipids > lignin dimers > sterols > fatty acids > su berins. On the other hand, the quantitative order of organic component s of the composted manure extract was phenols + monolignins > N compou nds > carbohydrates > peptides > alkylaromatics > lipids > fatty acids > sterols = lignin dimers > suberins, The relatively low total ion in tensity of the water extract of the composted manure and its greater a romaticity suggested that composting increased polymerization and cros s-linking and so led to the formation of larger molecules. Water-solub le organic C (DOC) extracted from the manures was used to study adsorp tion isotherms on soils varying in clay content from 3 to 54%. The ads orption of the DOC by the soils increased as the clay and organic matt er contents and the surface areas of the soils increased. Increased ad sorption of the DOC extracted from the composted manure appeared to be due to increased molecular weights of the major DOC components.