Abstract
Traditional assessment of plant nitrogen (N) relies on destructive chemical analysis, whereas optical sensors provide rapid, nondestructive estimates of crop N status. This study calibrated and validated a fluorescence/transmittance-based leaf-clip sensor (Dualex®) for diagnosing N status in cauliflower (Brassica oleracea var. botrytis) with Barcelona cultivar in a loam soil classified as Torripsamments over three seasons (2012–2014) in Agoncillo (La Rioja, Spain). Field trials comprised four N availability treatments in a randomized complete block design. At multiple dates, we measured leaf chlorophyll (Chl), epidermal flavonols (FLAV) and the Nitrogen Balance Index (NBI = Chl/FLAV) with Dualex®, together with plant biomass and total N in leaves and heads. The Dualex® NBI was linearly related to leaf total N concentration, enabling the derivation of a non-linear NBI–biomass critical curve analogous to critical N dilution models. For biomass ≥1 Mg ha−1, the critical curve correctly classified 92% of non-deficit treatments and 79% of deficit treatments (R2 = 0.8). Proposed NBI sufficiency ranges were 34–36 (≈1 Mg ha−1, ≈50% ground cover), 31–33 (≈2 Mg ha−1, button stage), and 27–29 (≈4 Mg ha−1, pre-harvest). These results demonstrate that Dualex® NBI can support in-season N management in cauliflower, reducing the need for destructive sampling.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. 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 9
Claim · model-written summary
Dualex NBI was linearly related to leaf total N concentration.
- Taxon
- cauliflower
Brassica oleracea var. botrytist0 - Outcome
- leaf total N concentratione0
- Comparator
- Dualex® NBIe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Dualex® NBI was linearly related to leaf total N concentration”
t0“cauliflower”
Claim · model-written summary
The NBI relationship enabled derivation of a nonlinear NBI–biomass critical curve.
- Taxon
- cauliflowerBrassica oleracea var. botrytist0
- Outcome
- non-linear NBI–biomass critical curvee0
- Comparator
- critical N dilution modelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“enabling the derivation of a non-linear NBI–biomass critical curve analogous to critical N dilution models”
t0“cauliflower”
Claim · model-written summary
For biomass ≥1 Mg ha−1, the curve correctly classified 92% of non-deficit treatments.
- Taxon
- cauliflowerBrassica oleracea var. botrytist0
- Outcome
- correctly classifiede0
- Value
- 92%e0
- Qualifier
- non-deficit treatmentse0
- Comparator
- deficit treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For biomass ≥1 Mg ha−1, the critical curve correctly classified 92% of non-deficit treatments and 79% of deficit treatments (R2 = 0.8).”
t0“cauliflower”
Claim · model-written summary
For biomass ≥1 Mg ha−1, the curve correctly classified 79% of deficit treatments.
- Taxon
- cauliflowerBrassica oleracea var. botrytist0
- Outcome
- correctly classifiede0
- Value
- 79%e0
- Qualifier
- deficit treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For biomass ≥1 Mg ha−1, the critical curve correctly classified 92% of non-deficit treatments and 79% of deficit treatments (R2 = 0.8).”
t0“cauliflower”
Claim · model-written summary
The critical curve had R2 of 0.8.
- Taxon
- cauliflowerBrassica oleracea var. botrytist0
- Outcome
- critical curvee0
- Value
- 0.8e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the critical curve correctly classified 92% of non-deficit treatments and 79% of deficit treatments (R2 = 0.8)”
t0“cauliflower”
Claim · model-written summary
Proposed NBI sufficiency was 34–36 at about 1 Mg ha−1 and about 50% ground cover.
- Taxon
- cauliflowerBrassica oleracea var. botrytist0
- Outcome
- NBI sufficiency rangese0
- Value
- 34–36e0
- Qualifier
- ≈1 Mg ha−1, ≈50% ground covere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proposed NBI sufficiency ranges were 34–36 (≈1 Mg ha−1, ≈50% ground cover), 31–33 (≈2 Mg ha−1, button stage), and 27–29 (≈4 Mg ha−1, pre-harvest).”
t0“cauliflower”
Claim · model-written summary
Proposed NBI sufficiency was 31–33 at about 2 Mg ha−1 and button stage.
- Taxon
- cauliflowerBrassica oleracea var. botrytist0
- Outcome
- NBI sufficiency rangese0
- Value
- 31–33e0
- Qualifier
- ≈2 Mg ha−1, button stagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proposed NBI sufficiency ranges were 34–36 (≈1 Mg ha−1, ≈50% ground cover), 31–33 (≈2 Mg ha−1, button stage), and 27–29 (≈4 Mg ha−1, pre-harvest).”
t0“cauliflower”
Claim · model-written summary
Proposed NBI sufficiency was 27–29 at about 4 Mg ha−1 and pre-harvest.
- Taxon
- cauliflowerBrassica oleracea var. botrytist0
- Outcome
- NBI sufficiency rangese0
- Value
- 27–29e0
- Qualifier
- ≈4 Mg ha−1, pre-harveste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proposed NBI sufficiency ranges were 34–36 (≈1 Mg ha−1, ≈50% ground cover), 31–33 (≈2 Mg ha−1, button stage), and 27–29 (≈4 Mg ha−1, pre-harvest).”
t0“cauliflower”
Claim · model-written summary
The authors conclude Dualex NBI can support in-season cauliflower nitrogen management with less destructive sampling.
- Taxon
- cauliflowerBrassica oleracea var. botrytise0
- Outcome
- in-season N management in cauliflowere0
- Qualifier
- reducing the need for destructive samplinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dualex® NBI can support in-season N management in cauliflower, reducing the need for destructive sampling”