CO2 enrichment at night affects the growth and yield of common beans

Authors: Bunce, James

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2014
Publication Date: 7/1/2014
Citation: Bunce, J.A. 2014. CO2 enrichment at night affects the growth and yield of common beans. Crop Science. 54:1-4.

Interpretive Summary: The concentration of carbon dioxide in the atmosphere continues to increase rapidly, and could have a large effect on future crop yields. Some experiments to determine the crop yield increase expected with rising atmospheric carbon dioxide concentration added carbon dioxide only during the daytime, without tests of whether elevation of carbon dioxide at night affected plant growth. In this experiment, we tested whether providing the elevated carbon dioxide treatment at night as well as during the daytime affected the growth and yield of beans. The results indicated that daytime only carbon dioxide enrichment greatly underestimated the yield increase likely to occur with rising atmospheric carbon dioxide concentrations. This work will be of importance to scientists attempting to predict crop yields at future atmospheric carbon dioxide concentrations.

Technical Abstract: Some experiments to determine the crop yield increase expected with rising atmospheric carbon dioxide concentration added carbon dioxide only during the daytime, without tests of whether elevation of carbon dioxide at night affected plant growth. In this experiment, two cultivars of common bean were grown in the field for four years in open top chambers in which carbon dioxide was added during the day or the night, both day and night, or not at all. Carbon dioxide was added to increase the concentration by 180 ppm above that of the ambient outside air, which averaged 392 ppm during the daytime and 503 ppm at night. In the two cultivars the average increase in seed yield over the ambient carbon dioxide treatment was 42% with daytime carbon dioxide enrichment, and 77% with continuous enrichment. In both cultivars, continuous carbon dioxide enrichment increased the area of individual leaflets by about 40% compared with daytime enrichment. Leaflet size was the same with daytime carbon dioxide enrichment and with no enrichment. In one of the cultivars, night time carbon dioxide elevation alone increased leaflet size and seed yield. The results indicated that carbon dioxide enrichment at night had important consequences for the growth and yield of these bean cultivars, and that daytime only carbon dioxide enrichment greatly underestimated the yield increase likely to occur with rising atmospheric carbon dioxide concentrations.