Effects of ozone and water stress on canopy temperature, water use, and water use efficiency of alfalfa
- Univ. of California, Riverside (USA)
- Univ. of California, Davis (USA)
Ozone (O{sub 3}) and soil water deficit are two environmental stresses that significantly affect the growth and yield of alfalfa (Medicago sativa L). However, little is known of the responses of field-grown alfalfa to O{sub 3}, and the effects of the interaction between O{sub 3} and water stress on canopy temperature and water relations of alfalfa have not been previously reported. The objective of this 2-yr study was to determine the interactive effects of O{sub 3} and soil water deficits on canopy temperatures, water use, and water use efficiency (WUE) of alfalfa. Alfalfa (cv. WL-514) was grown in 30-3- by 5.5-m plots on Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Typic Torriorthents) in Shafter, CA, and was exposed in open-top chambers to five levels of O{sub 3} for 12 h daily, from March to October of 1984 and 1985. Ozone treatments ranged from charcoal-filtered air (CF) to twice ambient O{sub 3} concentrations. Each plot received either normal amounts of irrigation (NI) or 30% less than normal (WS). Canopy temperature-air temperature differentials ({Tc}-T{sub a}) were significantly reduced by water stress an average of 27.9% in 1984 and 44.0% in 1985. Ozone also significantly reduced {Tc}-T{sub a} by 31% in NI and 37% in WS plots in 1984, but in 1985 O{sub 3} had no effect on {Tc}-T{sub a}. Water use, rate of soil water depletion, or depth of effective rooting zone were not affected by O{sub 3}, whereas water stress significantly reduced all three. Water use efficiency was significantly reduced by O{sub 3}, averaging 12% lower in nonfiltered compared with CF plots. The effects of O{sub 3} on WUE were attributed to premature senescence and abscission of older alfalfa leaves.
- OSTI ID:
- 5868872
- Journal Information:
- Agronomy Journal; (USA), Journal Name: Agronomy Journal; (USA) Vol. 80:3; ISSN 0002-1962; ISSN AGJOA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Combined effects of ozone and water stress on alfalfa growth and yield. [Medicago sativa L]
Combined effects of ozone and water stress on alfalfa growth and yield (journal version)
Related Subjects
540110
540310 -- Environment
Aquatic-- Basic Studies-- (1990-)
551000* -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
ALFALFA
BIOLOGICAL EFFECTS
CALIFORNIA
DROUGHTS
FEDERAL REGION IX
GROWTH
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
NORTH AMERICA
OZONE
PLANT GROWTH
PLANTS
SOILS
TEMPERATURE EFFECTS
USA