Abstract
Several narrow or broadband spectral indices can be calculated at varying spatial and spectral resolution, which can then be correlated with the physiological and nutritional status of the leaves. In a three-year trial carried out on fruiting, potted cv. Barbera grapevines subjected to full (N+) or no (N0) nitrogen supply, seasonal evolution of different leaf spectral indices were correlated with non-destructive chlorophyll readings (Minolta SPAD meter), leaf gas exchange, and vine performance. Throughout the entire trial, N starvation resulted in greater-than-proportional limitation of vine yield as compared to vegetative growth (55% compared to 26% less than values measured on N+). Indices calculated within the red-edge spectral domain had highest sensitivity to relative change between N+ and N0, also indicating that the promptest response was recorded at the median shoot zone level. Twelve broadband indices were linearly correlated with leaf blade N concentration at veraison, indicating that N values ≤ 1.8% of dry matter identify a limiting N status. Any of these indices collected at the leaf level can be reliably used as a non-destructive predictor of N availability, albeit due to significant between-year variation in their absolute values at a given N level, readings should always include a well-supplied N treatment.
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Claims 8
Claim · model-written summary
Nitrogen starvation limited vine yield by 55%.
VitisOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“N starvation resulted in greater-than-proportional limitation of vine yield as compared to vegetative growth (55% compared to 26% less than values measured on N+)”
Claim · model-written summary
Nitrogen starvation reduced vegetative growth by 26%.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“N starvation resulted in greater-than-proportional limitation of vine yield as compared to vegetative growth (55% compared to 26% less than values measured on N+)”
Claim · model-written summary
Red-edge indices had highest sensitivity to nitrogen treatment difference.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“Indices calculated within the red-edge spectral domain had highest sensitivity to relative change between N+ and N0”
Claim · model-written summary
The median shoot zone showed the promptest spectral response.
- Organ / stage
- median shoot zonee0
- Outcome
- promptest responsee0
- Direction
- prompteste0
- Value
- median shoot zone levele0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“the promptest response was recorded at the median shoot zone level”
Claim · model-written summary
Twelve broadband indices correlated linearly with leaf blade nitrogen at veraison.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“Twelve broadband indices were linearly correlated with leaf blade N concentration at veraison”
Claim · model-written summary
Leaf nitrogen at or below 1.8% dry matter indicates limiting N status.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“N values ≤ 1.8% of dry matter identify a limiting N status”
Claim · model-written summary
Leaf spectral indices can predict nitrogen availability nondestructively.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“Any of these indices collected at the leaf level can be reliably used as a non-destructive predictor of N availability”
Claim · model-written summary
Between-year variation requires a well-supplied N reference.
- Outcome
- readings should always include a well-supplied N treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“cv. Barbera (Vitis vinifera L.) Grapevines”
e0“due to significant between-year variation in their absolute values at a given N level, readings should always include a well-supplied N treatment”
The same questions in other papers
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This paper is about lacking the nutrient, so it counts the other way round here.
- positive
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This paper is about lacking the nutrient, so it counts the other way round here.
- positive
- no effect
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See all 21 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.