PARENT SESSION
Poster Session 30: Soil Ecology.

Wednesday, August 4 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.

Changes in ecosystem carbon following afforestation of native sand prairie.

Mellor, Nathan^*,1, Paul, Eldor², Drijber, Rhae³, Hellerich, Jeff³, Morris, Sherri¹, ¹ Bradley University, Peoria, IL² Colorado St. University, Fort Collins, CO³ University of Nebraska, Lincoln, Nebraska

ABSTRACT- Determining the amount of carbon stored and storage time as a function of land-management is important for predicting changes in the global carbon cycle. Soil carbon is stored in pools that differ in residence times: the active pool stores carbon for several hundred days, the slow pool stores carbon for tens to hundreds of years, and the resistant pool stores carbon for thousands of years. Carbon distribution throughout these pools is determined using long-term incubations. The Bessey Forest, a conifer forest planted on native sand prairie, was sampled to evaluate changes in carbon following land-use change. Litter and soil samples were taken from different vegetation types: native prairie, plantations of young cedar, old cedar, pine, and from mixed cedar/pine plantations. Cores were taken at depths of 0 to 5, 5 to 15, and 15 to 30 cm and long-term incubations were initiated. Respired CO₂ was determined periodically using an infrared gas analyzer. Respiration rates in the top 5 cm were greatest in the young cedar plantations (15.11 g CO₂-C/g soil) and lowest in pine (7.06 g CO₂-C/g soil) on day 7. These rates declined to 12.11 and 5.19 g respectively by day 52. Overall, this indicates greater active fraction carbon in the cedar than pines. Old cedar and prairie followed patterns of young cedar while mixed sites followed patterns of pine. Litter was greatest in pine stands and least in prairies. It is possible that pine stands have appreciable non-soil carbon sinks (e.g. litter). If ecosystems are to be used as sinks for atmospheric carbon, then we must know the size, location and residence times of carbon in these systems. Non-soil carbon components, such as litter, may be more easily lost to the atmosphere than belowground sinks.

Key words: afforestation, carbon storage, sand prairie