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Title: Phosphorus stress effects on growth and seed yield responses of nonnodulated soybean to elevated carbon dioxide

Journal Article · · Agronomy Journal; (USA)
 [1]; ;  [2]
  1. Duke Univ., Durham, NC (USA)
  2. North Carolina State Univ., Raleigh (USA)

The influence of P availability on plant responses to elevated atmospheric CO{sub 2} concentrations has received limited research attention. Therefore, an experiment was conducted to examine the effect of a wide range of P availabilities on plant response to enriched atmospheric CO{sub 2}. Nonnodulating soybean (Glycine max (L.) Merr., Lee) plants were grown from germination to maturity in controlled environment chambers at 350 or 700 {mu}L L{sup {minus}1} CO{sub 2}, respectively. Growth and yield were significantly increased by CO{sub 2} enrichment at all except the lowest P concentration. The stimulation of growth at high CO{sub 2} was consistently associated with increased leaf area, net assimilation rate, P uptake, and P utilization efficiency in the production of dry matter. When averaged over the four highest P levels, total root mass was increased 63% by CO{sub 2} enrichment, but P uptake efficiency per unit root mass was decreased 22%. The yield enhancement of 23 to 57% at high CO{sub 2} was associated with increases in the number and size of seed. Carbon dioxide enrichment had no significant effect on harvest index. The results indicate that CO{sub 2} enrichment can result in stimulation of growth and yield of nonnodulated, NO{sub 3}{sup {minus}}-fed soybean plants, even at concentrations of P that limit plant growth at ambient CO{sub 2} concentrations.

OSTI ID:
5923288
Journal Information:
Agronomy Journal; (USA), Vol. 80:6; ISSN 0002-1962
Country of Publication:
United States
Language:
English