ORGANIC-MATTER COMPARISON OF WETTABLE AND NONWETTABLE SOILS FROM BENTGRASS SAND GREENS

Previous studies have attributed hydrophobicity in sandy soils to alka line extractable macromolecular complexes, as well as lipid fractions, but have not included wettable soils for comparison. Our study was co nducted to compare the alkaline-extractable and lipid fractions of a n onwettable soul to a wettable soil from creeping bentgrass (Agrostis s tolonifera L. var. stolonifera) sand greens. Samples were collected fr om two sites and several extraction sequences performed on each. Humat es were extracted in 1.25 mol L-1 NaOH.Alkaline-extractable fractions were separated by precipitation with 6 mol L-1 HCI. Acid precipitated and nonprecipitated fractions were purified, lyophilized, and analyzed by Fourier transform infrared spectroscopy. In addition, the acid non precipitated fractions, which included fulvic acids, were analyzed by solid-phase C-13 nuclear magnetic resonance spectroscopy. Lipid fracti ons were extracted with a soxhlet apparatus using either hexane or met hanol as solvent. Lipid fractions were analyzed by gas chromatography- mass spectroscopy. No qualitative differences were observed with Site 1 extracts, and it appeared that hydrophobicity may have been at least partly due to physical or structural differences. Qualitative differe nces were observed with Site 2 extracts when initially extracted with methanol.