The Effect of Climate and Management on Carbon Fluxes of Three U.S. Southern Plains Ecosystems
Abstract
The Southern Great Plains are characterized by a fine-scale mixture of different land cover types, predominantly winter-wheat and grazed pasture, with relatively small holdings of other crops, native prairie, and switchgrass. Recent droughts and predictions of increased drought in the future have created concern for these ecosystems. We measured ecosystem carbon, water, and energy fluxes with eddy covariance systems in three different ecosystems characteristic to the Southern Great Plains: cultivated cropland, lightly grazed prairie, and new switchgrass fields, for 2 to 10 years. We identified three parameters dominating carbon and water exchange. First, precipitation during the growing season had a larger effect on plant productivity than annual precipitation. Second, summer-growing native prairies and switchgrass observed more seasonal droughts than winter-wheat because of the higher likelihood of dry soil conditions during summer. Third, management practices for crops were effective in suppressing evapotranspiration and decomposition after senescence (harvest and removal of secondary growth), and increased carbon uptake during the growing season (fertilization). Under severe drought conditions, these practices are not sufficient to maintain plant productivity. In light of future projections for wetter springs and drier summers in the Southern Great Plains, our study indicates increased native-ecosystem vulnerability to climate change over time.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.B43F..02R
- Keywords:
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- 0400 BIOGEOSCIENCES;
- 0428 BIOGEOSCIENCES Carbon cycling;
- 0429 BIOGEOSCIENCES Climate dynamics;
- 0402 BIOGEOSCIENCES Agricultural systems