Abstract
Few studies have attempted to investigate the combined effects of soil matric potential (Ψm) and osmotic potential (Ψs) on plant production and water use efficiency (WUE). The purpose of this study is to evaluate the synergistic and antagonistic effects of Ψm and Ψs associated with nitrogen (N) fertilization on spinach (Spinacia oleracea L.) growth traits and WUE. Five levels of salinity (1, 4, 7, 9, 11 dS m−1), three levels of water use amounts including deficit-irrigation (W–), full-irrigation (W0) and over-irrigation (W+), and four levels of N application rates (0, 50, 75, and 100% of N requirement) were applied. A new parameter namely "WUEθ" is suggested based on soil water content (θ). Results showed that water deficit combined with high saline irrigation water caused the most reduction in the plant biomass, leaf area index (LAI) and evapotranspiration (ET). The acquired plant yield coefficient (Ky) of 1.003 indicates that the spinach is a moderately salt-sensitive vegetable. The highest WUE was observed under deficit-irrigation and intermediate salinity conditions, which was attributed to an adaptation mechanism in the plant. However, WUEθ (R2 > 0.98) was a better predictor of the plant yield than WUE (R2 > 0.48). Nitrogen use efficiency (NUE) decreased with increasing salinity and water deficiency. Also, Ψm and Ψs had a synergistic interaction on yield and ET, while their effect on WUE and WUEθ was antagonistic. Salinity greater than drought reduced yield, while both had equal reducing effects on ET. Furthermore, WUE and WUEθ were more influenced by Ψm than Ψs.Research HighlightsThe new parameter WUEθ is a better predictor of the spinach plant yield than WUE.WUE and WUEθ are more influenced by water potential (Ψm) than osmotic potential (Ψs).Synergistic interaction of Ψm and Ψs on yield and ET, but antagonistic effect on WUE and WUEθ.Salinity greater than drought reduces yield, while both have equal reducing effects on ET.Ψm shows negative effects on yield and ET, but positive effects on WUE and WUEθ.
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Claims 13
Claim · model-written summary
Water deficit combined with high saline irrigation water caused the greatest reductions in plant biomass, LAI and evapotranspiration.
- Taxon
- spinach (Spinacia oleracea L.)
Spinacia oleraceae0 - Treatment
- water deficit combined with high saline irrigation watere1
- Outcome
- plant biomass, leaf area index (LAI) and evapotranspiration (ET)e1
- Direction
- most reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e1“Results showed that water deficit combined with high saline irrigation water caused the most reduction in the plant biomass, leaf area index (LAI) and evapotranspiration (ET)”
Claim · model-written summary
The acquired yield coefficient Ky of 1.003 indicates that spinach is moderately salt-sensitive.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Outcome
- plant yield coefficient (Ky)e2
- Value
- 1.003e2
- Qualifier
- moderately salt-sensitive vegetablee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e2“The acquired plant yield coefficient (Ky) of 1.003 indicates that the spinach is a moderately salt-sensitive vegetable”
Claim · model-written summary
The highest WUE was observed under deficit-irrigation and intermediate salinity conditions.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- deficit-irrigation and intermediate salinity conditionse3
- Outcome
- WUEe3
- Direction
- higheste3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e3“The highest WUE was observed under deficit-irrigation and intermediate salinity conditions, which was attributed to an adaptation mechanism in the plant”
Claim · model-written summary
The highest WUE under deficit-irrigation and intermediate salinity was attributed to an adaptation mechanism in spinach.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Outcome
- WUEe3
- Qualifier
- an adaptation mechanism in the plante3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e3“The highest WUE was observed under deficit-irrigation and intermediate salinity conditions, which was attributed to an adaptation mechanism in the plant”
Claim · model-written summary
WUEθ was a better predictor of spinach yield than WUE.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Outcome
- predictor of the plant yielde5
- Direction
- bettere5
- Value
- R2 > 0.98e5
- Qualifier
- R2 > 0.48e5
- Comparator
- WUEe5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e5“However, WUEθ (R2 > 0.98) was a better predictor of the plant yield than WUE (R2 > 0.48)”
Claim · model-written summary
Nitrogen use efficiency decreased with increasing salinity and water deficiency.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- increasing salinity and water deficiencye6
- Outcome
- Nitrogen use efficiency (NUE)e6
- Direction
- decreasede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e6“Nitrogen use efficiency (NUE) decreased with increasing salinity and water deficiency”
Claim · model-written summary
Ψm and Ψs had a synergistic interaction on spinach yield and ET.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- Ψm and Ψse7
- Outcome
- yield and ETe7
- Direction
- synergistice7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e7“Also, Ψm and Ψs had a synergistic interaction on yield and ET, while their effect on WUE and WUEθ was antagonistic”
Claim · model-written summary
Ψm and Ψs had an antagonistic interaction on WUE and WUEθ.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- Ψm and Ψse7
- Outcome
- WUE and WUEθe7
- Direction
- antagonistice7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e7“Also, Ψm and Ψs had a synergistic interaction on yield and ET, while their effect on WUE and WUEθ was antagonistic”
Claim · model-written summary
Salinity reduced spinach yield more than drought.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- Salinitye1
- Outcome
- yielde1
- Direction
- reducede1
- Comparator
- droughte1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e1“Salinity greater than drought reduced yield, while both had equal reducing effects on ET”
Claim · model-written summary
Salinity and drought had equal reducing effects on spinach ET.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- Salinitye1
- Outcome
- ETe1
- Direction
- equal reducing effectse1
- Comparator
- droughte1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e1“Salinity greater than drought reduced yield, while both had equal reducing effects on ET”
Claim · model-written summary
WUE and WUEθ were more influenced by Ψm than by Ψs.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- Ψme1
- Outcome
- WUE and WUEθe1
- Direction
- more influencede1
- Comparator
- Ψse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e1“Furthermore, WUE and WUEθ were more influenced by Ψm than Ψs”
Claim · model-written summary
Ψm had negative effects on spinach yield and ET.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- Ψme1
- Outcome
- yield and ETe1
- Direction
- negative effectse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e1“Ψm shows negative effects on yield and ET, but positive effects on WUE and WUEθ”
Claim · model-written summary
Ψm had positive effects on WUE and WUEθ.
- Taxon
- spinach (Spinacia oleracea L.)Spinacia oleraceae0
- Treatment
- Ψme1
- Outcome
- WUE and WUEθe1
- Direction
- positive effectse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on spinach (Spinacia oleracea L.) growth traits and WUE”
e1“Ψm shows negative effects on yield and ET, but positive effects on WUE and WUEθ”
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