Combined effects of ozone and water stress on alfalfa growth and yield. [Medicago sativa L]

Journal Article · · J. Environ. Qual.; (United States)

OSTI ID:5336278

Temple, P J; Benoit, L F; Lennox, R W; Reagan, C A; Taylor, O C

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), Journal Name: J. Environ. Qual.; (United States) Vol. 17:1; ISSN JEVQA
• Country of Publication: United States
• Language: English

Related Subjects

500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALFALFA
ATMOSPHERES
BACTERIA
BIOLOGICAL STRESS
CHRONIC EXPOSURE
CONTROLLED ATMOSPHERES
DROUGHTS
GROWTH
LEGUMINOSAE
MICROORGANISMS
OZONE
PLANT GROWTH
PLANTS
RHIZOBIUM
TOXICITY
YIELDS