Abstract
Abstract A 2‐yr study (1984 and 1985) designed to determine the interactive effects of ozone (O 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 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 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 3 treatments including charcoal‐filtered (CF), nonfiltered (NF), NF plus an additional 33, 67, or 100% of ambient O 3 concentrations (NF × 1.3, NF × 1.7, and NF × 2.0, respectively). Ambient O 3 concentrations averaged 0.049 µ L L −1 in 1984 and 0.042 µ L L −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 interaction between O 3 and water stress was statistically significant in 1985 and for combined 1984 and 1985 years. Seasonal yields for 1985 in NI plots were reduced 0, 14.9, 24.3, and 24.9% in NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively. Comparable seasonal yield reductions in WS plots were 5.9, 7.2, 13.5, and 18.1%. 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 3 was found on top growth. However, crown (underground stem) weights were significantly reduced by O 3 , suggesting that continued exposure to O 3 could shorten the productive life of alfalfa stands, in addition to its effect on yield.
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Claims 15
Claim · model-written summary
Water stress reduced seasonal yield about 10% in 1984.
- Taxon
- Alfalfa
Medicago sativat0 - Treatment
- Water stresse0
- Outcome
- total seasonal yielde0
- Direction
- reducede0
- Value
- 10%e0
- Qualifier
- 1984e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water stress reduced total seasonal yield about 10% in 1984”
t0“Alfalfa”
Claim · model-written summary
Water stress reduced seasonal yield 27% in 1985.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- Water stresse0
- Outcome
- total seasonal yielde0
- Direction
- reducede0
- Value
- 27%e0
- Qualifier
- 1985e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water stress reduced total seasonal yield about 10% in 1984 and 27% in 1985”
t0“Alfalfa”
Claim · model-written summary
Ozone significantly reduced yields in both years.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone significantly reduced yields in both years”
t0“Alfalfa”
Claim · model-written summary
Ozone and water stress interacted significantly in 1985 and combined years.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- O 3 and water stresse0
- Outcome
- interaction between O 3 and water stresse0
- Qualifier
- 1985 and for combined 1984 and 1985 yearse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the interaction between O 3 and water stress was statistically significant in 1985 and for combined 1984 and 1985 years”
t0“Alfalfa”
Claim · model-written summary
In normally irrigated plots, NF × 1.3 reduced 1985 yield 14.9%.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- NF × 1.3e0
- Outcome
- Seasonal yieldse0
- Direction
- reducede0
- Value
- 14.9e0
- Qualifier
- 1985 in NI plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal yields for 1985 in NI plots were reduced 0, 14.9, 24.3, and 24.9% in NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively”
t0“Alfalfa”
Claim · model-written summary
In normally irrigated plots, NH × 1.7 reduced 1985 yield 24.3%.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- NH × 1.7e0
- Outcome
- Seasonal yieldse0
- Direction
- reducede0
- Value
- 24.3e0
- Qualifier
- 1985 in NI plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal yields for 1985 in NI plots were reduced 0, 14.9, 24.3, and 24.9% in NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively”
t0“Alfalfa”
Claim · model-written summary
In normally irrigated plots, NF × 2.0 reduced 1985 yield 24.9%.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- NF × 2.0e0
- Outcome
- Seasonal yieldse0
- Direction
- reducede0
- Value
- 24.9%e0
- Qualifier
- 1985 in NI plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal yields for 1985 in NI plots were reduced 0, 14.9, 24.3, and 24.9% in NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively”
t0“Alfalfa”
Claim · model-written summary
In water-stressed plots, NF reduced 1985 yield 5.9%.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- NFe1
- Outcome
- seasonal yielde0
- Direction
- reductionse0
- Value
- 5.9e0
- Qualifier
- WS plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Comparable seasonal yield reductions in WS plots were 5.9, 7.2, 13.5, and 18.1%”
e1“NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively”
t0“Alfalfa”
Claim · model-written summary
In water-stressed plots, NF × 1.3 reduced 1985 yield 7.2%.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- NF × 1.3e1
- Outcome
- seasonal yielde0
- Direction
- reductionse0
- Value
- 7.2e0
- Qualifier
- WS plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Comparable seasonal yield reductions in WS plots were 5.9, 7.2, 13.5, and 18.1%”
e1“NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively”
t0“Alfalfa”
Claim · model-written summary
In water-stressed plots, NH × 1.7 reduced 1985 yield 13.5%.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- NH × 1.7e1
- Outcome
- seasonal yielde0
- Direction
- reductionse0
- Value
- 13.5e0
- Qualifier
- WS plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Comparable seasonal yield reductions in WS plots were 5.9, 7.2, 13.5, and 18.1%”
e1“NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively”
t0“Alfalfa”
Claim · model-written summary
In water-stressed plots, NF × 2.0 reduced 1985 yield 18.1%.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- NF × 2.0e1
- Outcome
- seasonal yielde0
- Direction
- reductionse0
- Value
- 18.1%e0
- Qualifier
- WS plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Comparable seasonal yield reductions in WS plots were 5.9, 7.2, 13.5, and 18.1%”
e1“NF, NF × 1.3, NH × 1.7, and NF × 2.0 treatments, respectively”
t0“Alfalfa”
Claim · model-written summary
Ozone dose-yield loss functions were homogeneous between years.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- yield loss functionse0
- Direction
- homogeneouse0
- Comparator
- 1984 and 1985e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ozone dose‐alfalfa yield loss functions were homogeneous between 1984 and 1985”
Claim · model-written summary
No cumulative multiyear ozone effect on top growth was found.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- multiple‐year exposure to O 3e0
- Outcome
- top growthe0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no evidence of a cumulative effect of multiple‐year exposure to O 3 was found on top growth”
t0“Alfalfa”
Claim · model-written summary
Ozone significantly reduced crown weights.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- O 3e0
- Outcome
- crown (underground stem) weightse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“crown (underground stem) weights were significantly reduced by O 3”
t0“Alfalfa”
Claim · model-written summary
The authors suggest continued ozone exposure could shorten productive stand life.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- continued exposure to O 3e0
- Outcome
- productive life of alfalfa standse0
- Direction
- shortene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“continued exposure to O 3 could shorten the productive life of alfalfa stands”
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See all 5 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.