ASSESSING SOIL DEGRADATION AFTER CONVERSION OF NATIVE ECOSYSTEMS TO AGRICULTURAL PRODUCTION

Authors: MARQUEZ, C - IOWA STATE UNIVERSITY; GARCIA, V - IOWA STATE UNIVERSITY; Cambardella, Cynthia; ISENHART, T - IOWA STATE UNIVERSITY; SCHULTZ, R - IOWA STATE UNIVERSITY

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2001
Publication Date: 10/25/2001
Citation: Marquez, C.O., Garcia, V.J., Cambardella, C.A., Isenhart, T., Schultz, R. 2001. Assessing soil degradation after conversion of native ecosystems to agricultural production [abstract]. American Society of Agronomy Meetings. s03-marquez210736-0.pdf.

Interpretive Summary:

Technical Abstract: The purpose of this study was to evaluate the effect of row crop agriculture on soil degradation through the quantification of total, light, and heavy soil carbon fractions and to study soil aggregate dynamics and carbon associated with aggregates in a long established riparian cool-season grass filter and a non-buffered annual row cropped riparian zone in central Iowa, USA. The soil aggregate dynamics model was used to analyze aggregate dynamics and carbon associated with aggregates. Soil degradation in the annual row cropped system resulted in the disruption of 19% of the macroaggregates. This disruption of macroaggregates exposes previously protected labile organic carbon to decomposers, resulting in a loss of 11.3 mg C g-1 and further destabilization of macroaggregates. The amount of total particulate organic C was three times greater in cool-season grass vs. cropped and accounted for 16% of the total organic carbon under cool season grass and 7% under cropped field. The results indicate that macroaggregates under cool-season grass are more stable and provide an important mechanism for C sequestration and support the higher amounts of light and heavy particulate organic matter C than cropped systems.