Using chlorophyll meter readings to determine N application rates for corn

dc.contributor.author Sawyer, John
dc.contributor.author Sawyer, J. E.
dc.contributor.author Barker, D. W.
dc.contributor.author Lundvall, J. P.
dc.contributor.author Barker, Daniel
dc.contributor.department Agronomy
dc.date 2018-02-18T08:50:35.000
dc.date.accessioned 2020-06-29T23:02:11Z
dc.date.available 2020-06-29T23:02:11Z
dc.date.copyright Thu Jan 01 00:00:00 UTC 2004
dc.date.embargo 2017-04-10
dc.date.issued 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>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/agron_conf/35/
dc.identifier.articleid 1041
dc.identifier.contextkey 10000216
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath agron_conf/35
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/4374
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/agron_conf/35/0-IPNI_Permission.pdf|||Fri Jan 14 23:43:58 UTC 2022
dc.source.bitstream archive/lib.dr.iastate.edu/agron_conf/35/2004_Sawyer_UsingChlorophyll.pdf|||Fri Jan 14 23:44:00 UTC 2022
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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