Improved process understanding of CO2-induced mechanisms on yield and yield quality of selected field-grown wheat genotypes
Final Report Abstract
In project P4, the effects of changing climatic conditions, in particular the ongoing rise in atmospheric carbon dioxide (CO2) concentrations, the increase in ambient temperature and the occurrence of extreme temperatures have been investigated by means of experimental approaches. We selected wheat (Triticum aestivum L.) as our test crop and grew wheat canopies under future climatic conditions to be expected in the coming decades. We used both strictly controlled conditions in climate chambers and field experiments. Climate chambers were operated in a way that guaranteed growing conditions very closely matching field conditions. For field experiments with different levels of CO2, we employed a new and sophisticated exposure system, a so-called free air carbon dioxide enrichment system (FACE). We could demonstrate that an increase in CO2 concentrations by 150 µmol mol^-1 above todays ambient concentrations (i.e. an increase from current c. 400 µmol mol^-1 to ca. 550 µmol mol^-1) will increase the yield of wheat by approximately 10%. At the same time, subtle, but important changes in the quality of wheat grains took place, such as reduced protein concentrations, which amounted c. -10%, reduced concentrations of important minerals (e.g. iron), and, as we could demonstrate for the first time, considerable changes in the protein composition. Thus, the potentially positive effect of increasing CO2 concentrations (higher yield) will most probably be counteracted by reductions in grain quality and disturbances of the protein and mineral element metabolism. Heat stress had the opposite effect on grain yield compared with CO2 enrichment – there was a clear reduction in yield. By comparing the effects of long-term temperature increases with those of shorter heat waves, we could also demonstrate the importance of shorter episodes of very high temperatures which will occur much more frequently in the future. Unfortunately, the positive effects of CO2 enrichment on grain yield could not fully counteract the negative effects of heat stress. Thus, under future climate conditions, no net increase of yield due to CO2 enrichment can be expected since the impact of CO2 as greenhouse gas and the climatic extremes arising from it will counteract the basically positive physiological effect of CO2. Furthermore, the problem of altered quality traits will have to be covered, i.e., there is a demand for new crops and/or varieties that can cope with more extreme climatic conditions and, at the same time, would not be subjected to losses in yield quality due to rising CO2 concentrations. Besides being published in scientific journals, the results obtained in P4 created substantial attention in public media. This concerns television reports as well as interviews in radio broadcasting and newspapers.
Publications
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2014. Incorporating dynamic root growth enhances the performance of Noah-MP at two contrasting winter wheat field sites. Water Resour. Res. 50, 1337-1356
Gayler, S., Wöhling, T., Grzeschik, M., Ingwersen, J., Wizemann, H.-D., Warrach-Sagi, K., Högy, P., Attinger, S., Streck, T., Wulfmeyer, V.
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2015. CO2 dose-response functions for wheat grain, protein and mineral yield based on FACE and open-top chamber experiments. Environ. Pollut. 198, 70-77
Pleijel, H., Högy, P.
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2015. On the use of the post-closure method uncertainty band to evaluate the performance of land surface models against eddy covariance flux data. Biogeosciences 12, 2311–2326
Ingwersen, J., Imukova, K., Högy, P., Streck, T.
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2015. Simulation-based projections of crop management and gross margin variance in contrasting regions of Southwest Germany. J. Agric. Studies 3, 79-98
Parker, P., Reinmuth, E., Ingwersen, J., Högy, P., Priesack, E., Wizemann, H.-D., Aurbacher, J.
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2015. Threeyear observations of water vapor and energy fluxes over agricultural crops in two regional climates of Southwest Germany. Meteorol. Z. 24, 39-59
Wizemann, H.D., Ingwersen, J., Högy, P., Warrach-Sagi, K., J., Streck, T., Wulfmeyer, V.
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2016. Design and performance of a new FACE (free air carbon dioxide enrichment) system for crop and short vegetation exposure. Env. Exp. Bot. 130, 151-161
Fangmeier, A., Torres-Toledo, V., Franzaring, J., Damsohn, W.
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2016. Simulating regional climateadaptive field cropping with fuzzy logic management rules and genetic advance. J. Agric. Sci. 154, 207-222
Parker, P.S., Ingwersen, J., Högy, P., Priesack, E., Aurbacher, J.
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2017. Contrasting effect of elevated atmospheric CO2 on the C/N ratio of faba bean and spring wheat residues exert only minor changes in the abundance and enzyme activities of soil proteolytic bacteria. Pedobiologia 62, 9-15
Rasche, F., Kramer, S., Enowashu, E., Mackie, K., Högy, P., Marhan, S.
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2017. Modeling perceptions of climatic risk in crop production. PLOS ONE, 0181954
Reinmuth, E., Parker, P.S., Aurbacher, J., Högy, P., Dabbert, S.
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2018. Coupling the land surface model NOAHMP with the generic crop growth model GECROS: Model description, calibration and validation. Agric. For. Meteorol. 262, 322-339
Ingwersen, J., Högy, P., Wizemann, H.-D., Warrach-Sagi, K., Streck, T.
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2018. How well does Noah-MP simulate the regional mean and spatial variability of topsoil water content in two agricultural landscapes in southwest Germany? J. Hydrometeorol. 19, 555–573
Poltoradnev, M., Ingwersen, J., Imukova, K., Högy, P., Wizemann, H.-D., Streck, T.
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2018. Physiological and proteomic evidence for the interactive effects of post-anthesis heat stress and elevated CO2 on wheat. Proteomics
Zhang, X., Högy, P., Wu, X., Schmid, I., Wang, X., Schulze, W., Jiang, D., Fangmeier, A.
