Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/1999
Publication Date: N/A
Technical Abstract: Chemical and physical fractionations were used to study the effect of cover-crop management practice on soil organic matter (SOM) characteristics. We isolated SOM from: a) Vetch/Rye, b) Rye alone, and c) Check (no cover crops) with various nitrogen fertilizer rates. Six humic acids (HA) and six fulvic acids (FA) were analyzed using solid-state **13C nuclear magnetic resonance (NMR) and diffuse reflectance fourier-transform infrared (DR-FTIR) spectroscopy techniques. The preliminary **13C NMR results indicate that HA from rye cover alone becomes more aromatic and less aliphatic than other 2 sites. Although DR-FTIR cannot be used to quantify the absolute C contents of structural groups, it can be used to generate peak ratios from which we can assess the relative enrichment or depletion of specific functional groups. We also examined elemental composition changes of the humic substances. These spectroscopic and elemental data will provide valuable information for assessing the effect of cover-crop systems on SOM quality.