Soil carbon, nitrogen, and aggregate stability are the main indicators of soil quality. These properties are controlling factors in the success of sustainable agricultural production. The objective of this study was to evaluate the changes of soil C, N, C/N ratio, and aggregate stability under typical agroecosystems in western Kentucky. Composite soil samples were collected from selected counties at depths of 0-10 cm and 10-20 cm. The agroecosystems utilized for this study were conventional tillage, no tillage, organic farming, livestock pasture, and forests. Soil organic matter was determined using the method of loss of ignition (LOI). Soil total N was analyzed using the Kjeldahl method.  Soil aggregates were measured using a wet sieving procedure.  The results showed that the soil organic C was high in wooded areas and forage fields for the topsoil layers. Crop fields had a comparably lower amount of soil organic C in both top soil and sub soil layers. The percent aggregation is easily identifiable in every agroecosystems. The wooded areas tested had the greatest aggregate stability followed by the forage fields and finally the crop fields. Further details and discussion about this study will be presented in the poster.

Keywords: Aggregation, Agroecosystem, Carbon, Nitrogen, Soil Quality