PARENT SESSION
Wednesday, August 9, 8:00-11:30 am
COS 49 - Biogeochemical processes and dynamics
L-13, Lobby Level, Cook Convention Center
Presiders: J Edwards and C Cleveland

SOM changes following planting of cedar and pine plantations on sandy native prairie.

Mellor, Nathan^*,1, Hellenrich, Jeff ², Drijber, Rhae ², Morris, Sherri³, Paul, Eldor¹, ¹ Colrado State University, Fort Collins, CO² University of Nebraska Lincoln, Lincoln, NE³ Bradley University, Peoria, IL

ABSTRACT- The Nebraska National Forest at Halsey consisting of cedars and pines planted on sandy native prairie was sampled to measure the amounts and distribution of SOM under cedars and pines planted on native-sandy prairie. The cedars contained a large amount of soil carbon in the top 5cm that appeared to be due to large input of fine roots and litter. Pine stands contained a large reservoir of litter C but lower levels of soil C and had a more negative ¹³C. These data suggest that the pine soils are degrading prairie carbon faster than cedar soils. This observation is supported by soil ¹³C and ¹³C-CO₂ values. Cedar soils contained the largest amount of total soil C and had a ¹³C more similar to that of the prairie than the pine soils. Cedar soils also contained a larger amount of soil Ca in the top 5cm. A strong correlation between Ca contents and soil C storage was found using structural analysis. The ¹³C-CO₂ data of the prairie soils showed a change of -2‰ during the 400 day incubation. This was attributed to the decomposition of more aromatic materials with time as there was no known previous change in species composition of the prairie. Our research suggests changes in soil C and nutrient content following land conversion from prairie to forest are dependent on the species planted on specific sites. If ecosystems are to be used as sinks for atmospheric C, then we must know the relative impacts of different management strategies on soil C pools and its microbiology so that we can prescribe management options that are likely to have the greatest C storage in the biomass, litter, and soils.

Key words: Ecosystem Processes, Soil Carbon, Afforestation