PARENT SESSION
Oral Session #35: Carbon and Nitrogen Cycling.
Presiding: D. Rothstein
Tuesday, August 6. 8:00 AM to 11:30 AM. Palo Verde Room, Radisson.
Increasing soil carbon and nitrogen stocks under tallgrass prairie: Influence of soil type.
MATAMALA, ROSER*,1, JASTROW, JULIE1, AMTHOR, JEFF2, GARTEN, CHARLIE3, MILLER, MICHAEL1, 1 Argonne National Laboratory, Argonne, IL2 US Department of Energy, Germantown, MD3 Oak Ridge National Laboratory, Oak Ridge, TN
ABSTRACT- Conversion from native vegetation to cropland leads to a rapid depletion of soil organic matter (SOM). Restoration of degraded soils and ecosystems is a major strategy for reversing SOM losses and enhancing soil carbon sequestration. Because the restoration of SOM is a slow process, chronosequence approaches offers unique opportunities to study the dynamics of SOM accrual. The series of prairie restorations at Fermilab (IL) was initiated in 1975 on soils that had been cultivated for over 100 years. The vegetation is dominated by C4 grasses with significant numbers of C3 forbs and grasses. We measured carbon and nitrogen stocks to a depth of one meter for two parallel chronosequences consisting of cultivated soil, 10 restored prairies and a virgin prairie remnant that differed in soil type as defined by microtopography, texture, and soil moisture. Preliminary results show that the prairie was highly effective at rebuilding soil carbon stocks. Carbon accrual, in the wetter soil type, was exponentially increasing at a rate of 0.5 gC Kg soil-1 y-1 in the surface 10 cm. Carbon inputs were dominated by root production. We expect the drier soils will have a lower rate of C accrual, but conclude that tallgrass prairies can rapidly restore SOM lost through cultivation and have the potential to sequester relatively large amounts of C in the soil.
KEY WORDS: SOIL CARBON AND NITROGEN STOCKS, TALL GRASS PRAIRIE, CARBON ACCRUAL, PLANT PRODUCTION