Simulated effects of a doubling of carbon dioxide on corn production in portions of the central US

One aspect of global change with consequence for agriculture is the greenhouse effect.'' In recent years many of the greenhouse gases'' have been increasing in concentration. The trace gas most often identified as a major contributor to the increased concentration of the greenhouse gases is carbon dioxide. Water vapor, although not a pollutant, remains as the most important greenhouse gas in the atmosphere. Global warming will result in increased evaporization and consequently, the concentration of atmospheric water vapor. Carbon dioxide, in addition to its importance as a greenhouse gas, also supplies the carbon for the photosynthetic reaction in plant growth. There are many reports in the literature which demonstrate that as the concentration of carbon dioxide increases the amount of photosynthate produced at a given light level will be increased. Thus, carbon dioxide acts as a fertilizer'' enhancing the growth process and the levels of grain and forage production. To simulate the effects of increases in carbon dioxide, it is necessary to develop a model of how plants respond to both these changes and any interactions between the two effects. The model must consider the effects of climate change on the water balance and crop development (rates of growth andmore » phenological stages). It must consider how these factors will interact with the changes induced in the plant by the increased carbon dioxide to either increased or decreased carbohydrate production. 16 refs., 15 figs., 7 tabs.« less