Lobell, D. B. and Hammer, G. L. and McLean, G. and Messina, C. and Roberts, M. J. and Schlenker, W. (2013) The critical role of extreme heat for maize production in the United States. Nature Climate Change, 3 (5). pp. 497-501. ISSN 1758-678X
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Article Link(s): http://dx.doi.org/10.1038/nclimate1832
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Statistical studies of rainfed maize yields in the United States(1) and elsewhere(2) have indicated two clear features: a strong negative yield response to accumulation of temperatures above 30 degrees C (or extreme degree days (EDD)), and a relatively weak response to seasonal rainfall. Here we show that the process-based Agricultural Production Systems Simulator (APSIM) is able to reproduce both of these relationships in the Midwestern United States and provide insight into underlying mechanisms. The predominant effects of EDD in APSIM are associated with increased vapour pressure deficit, which contributes to water stress in two ways: by increasing demand for soil water to sustain a given rate of carbon assimilation, and by reducing future supply of soil water by raising transpiration rates. APSIM computes daily water stress as the ratio of water supply to demand, and during the critical month of July this ratio is three times more responsive to 2 degrees C warming than to a 20% precipitation reduction. The results suggest a relatively minor role for direct heat stress on reproductive organs at present temperatures in this region. Effects of elevated CO2 on transpiration efficiency should reduce yield sensitivity to EDD in the coming decades, but at most by 25%.
|Business groups:||Crop and Food Science|
|Additional Information:||Lobell, David B. Hammer, Graeme L. McLean, Greg Messina, Carlos Roberts, Michael J. Schlenker, Wolfram NSF [SES-0962625]; NOAA [NA11OAR4310095]; Australian Research Council [LP100100495] We thank J. Jones and M. Burke for helpful comments. D.B.L., M.J.R. and W.S. were supported by NSF grant SES-0962625, and D.B.L. also by NOAA grant NA11OAR4310095. G.L.H. and G.M. were supported by grant LP100100495 from the Australian Research Council. Nature publishing group London|
|Keywords:||crop production climate-change simulation-model trends yield temperature field photosynthesis impacts deficit|
|Subjects:||Plant culture > Field crops > Corn. Maize|
Agriculture > Agriculture (General) > Agricultural meteorology. Crops and climate
|Deposited On:||17 Sep 2013 03:19|
|Last Modified:||17 Sep 2013 03:19|
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