Abstract
Abstract An experiment was conducted on Norfolk sandy loam soil (Fine‐loamy, siliceous, thermic Typic Kandiudults) during two years to determine the feasibility of using field chlorophyll measurements for evaluation of corn (Zea mays L.) N status. Nitrogen was applied at rates of 56, 112, 168, 224, 280 and 336 kg ha‐1 to establish a range of corn chlorophyll levels, tissue N concentrations, and grain yields. At the V10 and midsilk stages of growth, field chlorophyll measurements were taken with a hand‐held chlorophyll meter (SPAD‐502 Chlorophyll Meter, Minolta Camera Co., Ltd., Japan)3 and tissue N was determined. A typical curvilinear grain yield response to N fertilizer was observed both years; maximum agronomic yields were obtained with 227 and 242 kg N ha1, respectively, in 1990 and 1991. Tissue N concentrations at V10 and midsiik were a good predictor of grain yield. Field chlorophyll measurements were highly correlated with tissue N concentrations at both growth stages during both years of the study. Field chlorophyll measurements had excellent grain yield prediction capabilities, even at V10, which shows promise for utilization of this tool for in‐season N recommendations. However, further calibration of field chlorophyll measurements will be required prior to routine use for corn N recommendation purposes.
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Claims 7
Claim · model-written summary
A curvilinear grain yield response to N fertilizer was observed in both years of corn.
- Taxon
- corn
Zea mays subsp. mayst0 - Treatment
- N fertilizere1
- Outcome
- grain yield responsee1
- Qualifier
- curvilineare1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“A typical curvilinear grain yield response to N fertilizer was observed both years”
t0“evaluation of corn nitrogen status”
Claim · model-written summary
The maximum agronomic yield of corn was obtained at 227 kg N ha1 in 1990.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- kg N ha1e2
- Outcome
- maximum agronomic yieldse2
- Direction
- maximume2
- Value
- 227e2
- Qualifier
- 1990e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“maximum agronomic yields were obtained with 227 and 242 kg N ha1, respectively, in 1990 and 1991”
t0“evaluation of corn nitrogen status”
Claim · model-written summary
The maximum agronomic yield of corn was obtained at 242 kg N ha1 in 1991.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- kg N ha1e2
- Outcome
- maximum agronomic yieldse2
- Direction
- maximume2
- Value
- 242e2
- Qualifier
- 1991e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“maximum agronomic yields were obtained with 227 and 242 kg N ha1, respectively, in 1990 and 1991”
t0“evaluation of corn nitrogen status”
Claim · model-written summary
Tissue N concentrations at V10 and midsilk were a good predictor of corn grain yield.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- V10 and midsiike3
- Outcome
- grain yielde3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Tissue N concentrations at V10 and midsiik were a good predictor of grain yield”
t0“evaluation of corn nitrogen status”
Claim · model-written summary
Field chlorophyll measurements were highly correlated with tissue N concentrations at both growth stages during both years.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- both growth stagese4
- Compound
- chlorophylle4
- Outcome
- tissue N concentrationse4
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“Field chlorophyll measurements were highly correlated with tissue N concentrations at both growth stages during both years”
t0“evaluation of corn nitrogen status”
Claim · model-written summary
Field chlorophyll measurements had excellent grain yield prediction capability for corn, even at V10.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- V10e5
- Compound
- chlorophylle5
- Outcome
- grain yield prediction capabilitiese5
- Value
- excellente5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Field chlorophyll measurements had excellent grain yield prediction capabilities, even at V10”
t0“evaluation of corn nitrogen status”
Claim · model-written summary
Field chlorophyll measurement shows promise for utilization in corn N management.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- utilization of this toole6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“which shows promise for utilization of this tool”
t0“evaluation of corn nitrogen status”
The same questions in other papers
nitrogen · yield · Zea mays (maize)Positive and negative results
1,905 papers in the same direction as this paper · 234 in the opposite direction · 45 reporting no difference from an alternative
- positive
- positive
- negative
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