|MANJUNATHA, PRIYANKA - Oklahoma State University|
|Turner, Kenneth - Ken|
Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/3/2017
Publication Date: 12/11/2017
Citation: Wagle, P., Manjunatha, P., Gowda, P.H., Northup, B.K., Neel, J.P., Turner, K.E., Steiner, J.L. 2017. CO2 dynamics in winter wheat and canola under different management practices in the southern Great Plains [abstract]. American Geophysical Union. Available at: http://adsabs.harvard.edu/abs/2017AGUFM.B11E1703W.
Interpretive Summary: Abstract only
Technical Abstract: Rising atmospheric carbon dioxide (CO2) concentration and increased air temperature and climatic variability concerns have prompted considerable interest regarding CO2 dynamics of terrestrial ecosystems in response to major climatic and biophysical factors. However, detailed information on CO2 dynamics in winter wheat (Triticum aestivum L.) and canola (Brassica napus L.) under different agricultural management practices is lacking. As a part of the GRL-FLUXNET, a cluster of eight eddy covariance (EC) systems was deployed on the 420-ha Grazinglands Research on agroEcosystems and the ENvironment (GREEN) Farm at the United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Grazinglands Research Laboratory (GRL), El Reno, OK. The GRL is also one of 18 USDA-ARS Long-Term Agroecosystem Research (LTAR) network sites in the United States. A 4-year crop rotation plan at the farm includes winter wheat for grain only, graze-grain, and graze-out, and canola under conventional till and no-till management conditions. Biometric measurements such as biomass, leaf area index (LAI), canopy cover %, canopy height, and chlorophyll content were collected approximately every 16 days to coincide with Landsat satellite overpass dates. As expected, biomass and LAI were highest in the grain only wheat fields followed by graze-grain and graze-out wheat fields, but they were similar for till and no-till wheat fields within the same grazing practice. Biomass and LAI were similar in till and no-till canola in fall 2016, but both were substantially lower in no-till compared to tilled canola during spring 2017 due to more severe winter damage. Because net ecosystem CO2 exchange (NEE) is strongly regulated by vegetation cover, the magnitudes of NEE were highest in the grain only wheat fields due to more biomass and LAI, followed by graze-grain and graze-out wheat fields. Similarly, the magnitudes of NEE were also higher in tilled canola (i.e., higher biomass and LAI) than in no-till. Moving forward, our clustered and paired EC towers can provide insights into the effects of tillage and different grazing management practices on CO2 dynamics in winter wheat and the effects of tillage on CO2 dynamics in canola production systems.