Abstract
Decision support tools for non-destructive estimation of rice crop nitrogen (N) status (e.g., chlorophyll meter [SPAD] or leaf color chart [LCC]) are an established technology for improved N management in irrigated systems, but their value in rainfed environments with frequent abiotic stresses remains untested. Therefore, we studied the effect of drought, salinity, phosphorus (P) deficiency, and sulfur (S) deficiency on leaf N estimates derived from SPAD and LCC measurements in a greenhouse experiment. Linear relations between chlorophyll concentration and leaf N concentration based on dry weight (Ndw) between SPAD values adjusted for leaf thickness andNdwand between LCC scores adjusted for leaf thickness andNdwcould be confirmed for all treatments and varieties used. Leaf spectral reflectance measurements did not show a stress-dependent change in the reflectance pattern, indicating that no specific element of the photosynthetic complex was affected by the stresses and at the stress level applied. We concluded that SPAD and LCC are potentially useful tools for improved N management in moderately unfavorable rice environments. However, calibration for the most common rice varieties in the target region is recommended to increase the precision of the leaf N estimates.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 6
Claim · model-written summary
Chlorophyll concentration and leaf nitrogen concentration had linear relations across treatments and varieties.
- Taxon
- Rice
Oryza sativat0 - Compound
- chlorophyll concentratione0
- Outcome
- leaf N concentration based on dry weight (Ndw)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Linear relations between chlorophyll concentration and leaf N concentration based on dry weight (Ndw)”
t0“Rice”
Claim · model-written summary
Thickness-adjusted SPAD values related linearly to leaf nitrogen concentration across treatments and varieties.
- Taxon
- RiceOryza sativat0
- Outcome
- SPAD values adjusted for leaf thicknesse0
- Qualifier
- all treatments and varieties usede0
- Comparator
- Ndwe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“between SPAD values adjusted for leaf thickness andNdwand between LCC scores adjusted for leaf thickness andNdwcould be confirmed for all treatments and varieties used”
t0“Rice”
Claim · model-written summary
Thickness-adjusted LCC scores related linearly to leaf nitrogen concentration across treatments and varieties.
- Taxon
- RiceOryza sativat0
- Outcome
- LCC scores adjusted for leaf thicknesse0
- Comparator
- Ndwe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“LCC scores adjusted for leaf thickness andNdwcould be confirmed for all treatments and varieties used”
t0“Rice”
Claim · model-written summary
Rice leaf spectral reflectance did not show stress-dependent pattern changes.
- Taxon
- RiceOryza sativat0
- Treatment
- stresse0
- Outcome
- reflectance patterne0
- Direction
- did not show a stress-dependent changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf spectral reflectance measurements did not show a stress-dependent change in the reflectance pattern”
t0“Rice”
Claim · model-written summary
The authors concluded that SPAD and LCC could aid nitrogen management in moderately unfavorable rice environments.
- Taxon
- riceOryza sativae0
- Outcome
- improved N managemente0
- Qualifier
- moderately unfavorable rice environmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SPAD and LCC are potentially useful tools for improved N management in moderately unfavorable rice environments”
Claim · model-written summary
The authors recommend regional variety calibration to improve precision of leaf nitrogen estimates.
- Taxon
- riceOryza sativae0
- Outcome
- calibration for the most common rice varieties in the target regione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“calibration for the most common rice varieties in the target region is recommended to increase the precision of the leaf N estimates”