Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates

• DOI: 10.3390/soilsystems4010006
• Publication Date: 2020-01-15T15:30:27Z
• Authors: Michael V. Schaefer; Nathaniel A. Bogie; Daniel Rath; Alison R. Marklein; Abdi Garniwan; Thomas Haensel; Ying Lin; Claudia C. Avila; Peter S. Nico; Kate M. Scow; Eoin L. Brodie; William J. Riley; Marilyn L. Fogel; Asmeret Asefaw Berhe; Teamrat A. Ghezzehei; Sanjai Parikh; Marco Keiluweit; Samantha C. Ying
• Keywords: Soil carbon; Crop Rotation; Carbon fibers

Increasing soil organic carbon (SOC) stocks in agricultural soils can contribute to stabilizing or even lowering atmospheric greenhouse gas (GHG) concentrations. Cover crop rotation has been shown increase SOC and provide productivity benefits for agriculture. Here we used a split field design evaluate the short-term effect of cover on distribution chemistry using combination bulk, isotopic, spectroscopic analyses size-and density-separated aggregates. Macroaggregates (>250 µm) incorporated additional plant material with as evidenced by more negative δ13C values (−25.4‰ compared −25.1‰ without crop) increased phenolic (plant-like) resonance NEXAFS spectra. Iron EXAFS data showed that Fe pool was composed 17–21% oxide remainder mix primary secondary minerals. Comparison oxalate dithionite extractions suggests may also crystallinity, especially dense (>2.4 g cm−3) fraction. were across density fractions bulk soil, indicating presence less processed carbon. Although no significant difference observed mass per basis between fields after one season, isotopic reveal enhanced movement aggregates soil.