Tuesday, November 6, 2007
204-5
Topo- and Chrono-sequence Effects on Soil Carbon Dynamics of Tall-grass Prairie and Cropland.
Jose G. Guzman and Mahdi Al-Kaisi. Agronomy, Iowa State University, 2104 Agronomy Hall, Ames, IA 50010
In recent years, conversion of crop and marginal land to reconstructed prairie has been gaining momentum due to the prairies’ aesthetic and environmental values. However, little attention has been given to the belowground biogeochemical processes, which has potential to reduce soil erosion and sequester significant amounts of atmospheric CO2 in the soil. In 2006, three reconstructed tall-grass prairies established during 1993, 1998, and 2003, as well as cropland (1870), and native tall-grass prairie sites were chosen under relatively close proximities and similar soil properties. The focus of the study was to examine slope positioning and time of establishment of tall-grass prairies and cropland effects on soil physical, chemical, and biological properties. Furthermore, aboveground parameters such as plant biomass, vegetation type, and photosynthesis were evaluated to establish linkages with soil surface CO2 efflux. Preliminary results show soil carbon dynamics affected by topography, due to its impact on soil carbon distribution, root and soil microbial populations and other related properties as influenced by time. Additionally, early model results indicate that certain type of grasses can affect soil surface CO2 efflux depending on growing conditions. Evaluating these parameters will help us understand the impacts of landscape position, time, and management practices on soil carbon sequestration.