Abstract
We investigated whether drought-induced impairment of grassland species can be explained directly by plant water deficit or by water-driven limitation of nitrogen (N) and/or carbohydrate sources. In a field experiment, a severe drought treatment was applied on monocultures of Lolium perenne L. (cv. Alligator) (Lp) and Trifolium repens L. (cv. Hebe) (Tr) by using rainout shelters excluding all precipitation, and effects were compared to a rainfed control. Three species-fertiliser treatments were set up, crossed with the drought treatment. The two species were fertilised equally with N (200 kg N ha −1 year −1 ), and an additional high N fertilisation treatment was established for L. perenne (Lp highN , 500 kg N ha −1 year −1 ). Severe soil water deficit led to significantly lower leaf water potentials in all species-fertiliser treatments ( P < 0.001) down to approximately −1.2 MPa and, on average, to a 79% reduction in living plant biomass above 7 cm harvest height ( P < 0.001), indicating strong plant water deficits. Under the drought treatment, living plant biomass above 7 cm did not differ among species-fertiliser treatments. Plant-available soil N was 84% lower ( P ≤ 0.01) and plant N concentrations were 24% less ( P < 0.001) under the drought than under the rainfed control treatment, with Lp always being more N limited than Lp highN and Tr. Nitrate concentrations in water-limited plants were generally very low (< 0.85 mg g −1 dry matter), whereas non-structural carbohydrates were distinctly greater under the drought treatment in Lp (+62%), Lp highN (+46%), and Tr (+18%). Restricted biomass production of these forage species under severe drought can primarily be explained by plant water deficits and secondarily by drought-induced limitation of N supply. However, growth seems not to be limited by carbohydrate source activity, as carbohydrates accumulated with water deficiency.
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Claims 11
Claim · model-written summary
Drought lowered leaf water potentials in all species-fertiliser treatments.
- Taxon
- Lolium perenne L.
Lolium perennet0 - Treatment
- Severe soil water deficite0
- Outcome
- leaf water potentialse0
- Direction
- lowere0
- Value
- −1.2 MPae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Severe soil water deficit led to significantly lower leaf water potentials in all species-fertiliser treatments ( P < 0.001) down to approximately −1.2 MPa”
t0“Lolium perenne L.”
Claim · model-written summary
Drought reduced living biomass by 79% on average.
- Taxon
- Trifolium repens L.
Trifolium repenst0 - Treatment
- Severe water deficitt0
- Outcome
- living plant biomass above 7 cm harvest heighte0
- Direction
- reductione0
- Value
- 79%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on average, to a 79% reduction in living plant biomass above 7 cm harvest height ( P < 0.001)”
t0“Severe water deficit restricts biomass production of Lolium perenne L. and Trifolium repens L. and causes foliar nitrogen but not carbohydrate limitation”
Claim · model-written summary
Drought biomass did not differ among species-fertiliser treatments.
- Taxon
- Lolium perenne L.Lolium perennet0
- Treatment
- drought treatmente0
- Outcome
- living plant biomass above 7 cme0
- Direction
- did not differe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under the drought treatment, living plant biomass above 7 cm did not differ among species-fertiliser treatments”
t0“Lolium perenne L.”
Claim · model-written summary
Drought reduced plant-available soil nitrogen by 84%.
- Taxon
- Lolium perenne L.Lolium perennet0
- Treatment
- droughte0
- Outcome
- Plant-available soil Ne0
- Direction
- lowere0
- Value
- 84%e0
- Comparator
- rainfed control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant-available soil N was 84% lower ( P ≤ 0.01) and plant N concentrations were 24% less ( P < 0.001) under the drought than under the rainfed control treatment”
t0“Lolium perenne L.”
Claim · model-written summary
Drought reduced plant nitrogen concentration by 24%.
- Taxon
- Trifolium repens L.Trifolium repenst0
- Treatment
- droughte0
- Outcome
- plant N concentrationse0
- Direction
- lesse0
- Value
- 24%e0
- Comparator
- rainfed control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plant N concentrations were 24% less ( P < 0.001) under the drought than under the rainfed control treatment”
t0“Trifolium repens L.”
Claim · model-written summary
Low nitrogen treatment Lp was more nitrogen limited than high nitrogen Lp and Tr.
- Taxon
- Lolium perenne L.Lolium perennet0
- Outcome
- more N limitede0
- Direction
- more N limitede0
- Comparator
- Lp highN and Tre0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lp always being more N limited than Lp highN and Tr”
t0“Lolium perenne L.”
Claim · model-written summary
Nitrate concentrations in water-limited plants were generally below 0.85 mg per gram dry matter.
- Taxon
- Lolium perenne L.Lolium perennet0
- Outcome
- Nitrate concentrationse0
- Direction
- very lowe0
- Value
- < 0.85 mg g −1 dry mattere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrate concentrations in water-limited plants were generally very low (< 0.85 mg g −1 dry matter)”
t0“Lolium perenne L.”
Claim · model-written summary
Drought increased non-structural carbohydrate in Lp by 62%.
- Taxon
- Lolium perenne L.Lolium perennet0
- Material
- Lpe0
- Treatment
- drought treatmente0
- Outcome
- non-structural carbohydratese0
- Direction
- greatere0
- Value
- +62%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“non-structural carbohydrates were distinctly greater under the drought treatment in Lp (+62%)”
t0“Lolium perenne L.”
Claim · model-written summary
Drought increased non-structural carbohydrate in Lp highN by 46%.
- Taxon
- Lolium perenne L.Lolium perennet0
- Material
- Lp highNe0
- Treatment
- drought treatmente0
- Outcome
- non-structural carbohydratese0
- Direction
- greatere0
- Value
- +46%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“non-structural carbohydrates were distinctly greater under the drought treatment in Lp (+62%), Lp highN (+46%)”
t0“Lolium perenne L.”
Claim · model-written summary
Drought increased non-structural carbohydrate in Tr by 18%.
- Taxon
- Trifolium repens L.Trifolium repenst0
- Material
- Tre0
- Treatment
- drought treatmente0
- Outcome
- non-structural carbohydratese0
- Direction
- greatere0
- Value
- +18%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“non-structural carbohydrates were distinctly greater under the drought treatment in Lp (+62%), Lp highN (+46%), and Tr (+18%)”
t0“Trifolium repens L.”
Claim · model-written summary
Authors attribute biomass restriction mainly to water deficit and secondarily to nitrogen limitation.
- Taxon
- Lolium perenne L.Lolium perennet0
- Outcome
- Restricted biomass productione0
- Qualifier
- plant water deficits and secondarily by drought-induced limitation of N supplye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Restricted biomass production of these forage species under severe drought can primarily be explained by plant water deficits and secondarily by drought-induced limitation of N supply”
t0“Lolium perenne L.”
The same questions in other papers
drought · quality: sugar starch · Trifolium repens (white clover)Positive and negative results
1 in the opposite direction
- negative
drought · quality: sugar starch · Lolium perenne (perennial ryegrass)Positive and negative results
2 in the opposite direction
- no effect
- negative
drought · yield · Trifolium repens (white clover)Positive and negative results
9 papers in the same direction as this paper · 5 in the opposite direction
- negative
- positive
- positive
11 papers more in this group
See all 15 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.