Combined effects of ozone and water stress on alfalfa growth and yield. [Medicago sativa L]
A 2-yr study (1984 and 1985) designed to determine the interactive effects of ozone (O/sub 3/) and water stress on alfalfa (Medicago sativa L. cv. WL-514) was conducted in Shafter, CA. The objectives of this study were to develop O/sub 3/ dose-yield response functions for alfalfa, to determine how water stress could alter these functions, and to describe the cumulative effects of multiple-year exposures to O/sub 3/ on this perennial crop. Field-grown alfalfa, raised under normally irrigated (NI) or water-stressed (WS) conditions in open-top chambers, was exposed to five O/sub 3/ treatments including charcoal-filtered (CF), nonfiltered (NF), and NF plus an additional 33, 67, or 100% of ambient O/sub 3/ concentrations. Ambient O/sub 3/ concentrations averaged 0.049 ..mu..L L/sup -1/ in 1984 and 0.042 ..mu..L L/sup -1/ in 1985 for the seasonal 12-h (0900-2100) means from April to October. Water stress reduced total seasonal yield about 10% in 1984 and 27% in 1985. Ozone significantly reduced yields in both years, and the interactions between O/sub 3/ and water stress was statistically significant in 1985 and for combined 1984 and 1985 years. Ozone dose-alfalfa yield loss functions were homogeneous between 1984 and 1985 and no evidence of a cumulative effect of multiple-year exposure to O/sub 3/ was found on top growth. However, crown (underground stem) weights were significantly reduced by O/sub 3/, suggesting that continued exposure to O/sub 3/ could shorten the productive life of alfalfa stands, in addition to its effect on yield.
- Research Organization:
- Univ. of California, Riverside (USA)
- OSTI ID:
- 5336278
- Journal Information:
- J. Environ. Qual.; (United States), Vol. 17:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
ALFALFA
PLANT GROWTH
DROUGHTS
BIOLOGICAL STRESS
OZONE
TOXICITY
CHRONIC EXPOSURE
CONTROLLED ATMOSPHERES
YIELDS
ATMOSPHERES
BACTERIA
GROWTH
LEGUMINOSAE
MICROORGANISMS
PLANTS
RHIZOBIUM
560300* - Chemicals Metabolism & Toxicology
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)