Effects of Carbon Dioxide Enrichment and Soil Water on Maize1
- K. M. King and
- D. H. Greer2
The current global rise in atmospheric CO2 concentration may lead to changes in yield and water use of crops. This study was done to determine the effects of increased CO2 in combination with soil water levels on the growth, yield, transpiration, and water use efficiency of maize (Zea mays L.). Corn plants (cv. PX74) were grown in Opiki humic silty clay loam (fine, illitic, mesic Histic Humaquepts) soil in 22-L pots from emergence to maturity (111 days) in controlled-environment rooms at CO2 concentrations of 350/360,600/ 650, and 850/900 µL L−1 (day/night). Within each room, at a given CO2 concentration, the plants were subjected to one of three soil water treatments: complete replacement of weekly transpiration (control) and 75 and 50% replacement of the control transpiration. The 350 µL L−1 treated plants produced an average of 401 g dry matter across all water treatments and the 600 and 850 µL L−1 treated plants produced an average of 431 and 436 g dry matter per plant, respectively. The differences in total dry matter between the 600 and 850 µL L−1 treated plants remained nonsignificant throughout the experiment. There were significant differences between all soil water treatments in dry matter production with the low soil water level averaging 284 g and the medium and high water level averaging 440 and 544 g plant−1, respectively. Transpiration was reduced with increased CO2 concentration and was 80.5 and 70.4% at 600 and 850 µL L−1, respectively, of that at 350 µL L−1 averaged across water treatments. The water use efficiency (WUE) increased markedly with increased CO2 concentration. At 600 and 850 µL L−1 the WUE was 34 and 55% greater, respectively, than at 350 µL L−1. Further work is needed on the applicability of this controlled environment experiment to the real world.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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