Using chlorophyll meter readings to determine N application rates for corn Sawyer, John Sawyer, J. E. Barker, D. W. Lundvall, J. P. Barker, Daniel
dc.contributor.department Agronomy 2018-02-18T08:50:35.000 2020-06-29T23:02:11Z 2020-06-29T23:02:11Z Thu Jan 01 00:00:00 UTC 2004 2017-04-10 2004-01-01
dc.description.abstract <p>One method for refining nitrogen (N) application in corn is use of in-season crop sensing. To aid producers in making decisions regarding N rate adjustments, a calibrated relationship between sensor-derived information and expected N application need should be established. Nitrogen rate trials were conducted at multiple sites across Iowa in 2001-2003. Nitrogen was applied at or shortly after corn planting. Minolta SI'AD chlorophyll meter (CM) readings were collected at the R1 growth stage from the ear leaf. The results show a statistically significant quadratic-plateau relationship between relative chlorophyll meter (RCM) values and differential from economic optimum N rate (R' = 0.69, P < 0.001). The regression fit resulted in a 0.97 RCM value at zero differential from economic optimum N. A related study in 2003 at six N rate by crop rotation sites showed RCM values at the V15 and R1 growth stages were similar. This indicates adequate time is available to collect readings after significant corn N uptake and before making in-season N adjustments. This relationship between RCM value and differential from economic optimum N rate could be used by producers to determine additional N need.</p>
dc.description.comments <p>This is a proceeding from <em>Thirty-Fourth North Central Extension-Industry Soil Fertility Conference </em><em></em>20 (2004): 136. Posted with permission.</p>
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dc.identifier archive/
dc.identifier.articleid 1041
dc.identifier.contextkey 10000216
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath agron_conf/35
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 23:43:58 UTC 2022
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dc.subject.disciplines Agricultural Science
dc.subject.disciplines Agriculture
dc.subject.disciplines Agronomy and Crop Sciences
dc.title Using chlorophyll meter readings to determine N application rates for corn
dc.type article
dc.type.genre conference
dspace.entity.type Publication
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