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dc.contributor.authorJones, Justin Rodgersen_US
dc.date.accessioned2013-05-16T08:00:09Z
dc.date.available2013-05-16T08:00:09Z
dc.date.issued2013-05-15en_US
dc.identifier.othervt_gsexam:544en_US
dc.identifier.urihttp://hdl.handle.net/10919/22052
dc.description.abstractCorn requires the most nitrogen (N) of cereal grain crops and N supply is correlated with grain yield.  Canopy reflectance has been used to assess crop N needs and to derive optimum application rates in mid-season corn.  Canopy reflectance has not been useful for N rate determination in early season corn because of low biomass and the sensing background can interfere, or overwhelm crop canopy reflectance measures.  Widespread adoption of canopy reflectance as a basis for generating in-season corn N rates would be more likely if N rate recommendations could be made early, i.e. by the V6 growth stage.  The objectives of this research were to: i) examine the influence of soil color, soil moisture, surface crop residues, and sensor orientation on normalized difference vegetation index (NDVI) readings from corn from planting through the V6 growth stage; and ii) evaluate the effect of sensor orientation and field of view at early corn growth stages on the relationship between NDVI and corn biomass, N uptake, and chlorophyll meter readings.  Soil color, soil moisture, crop residue type, and sensor orientation influenced reflectance and these factors were much more influential when sensing plants with low biomass.  Canopy reflectance was capable of differentiating between N rates in the field and altering sensor orientation did not minimize sensing background influence or improve the ability of the sensor to distinguish plant N status.  Even when canopy reflectance detected differences in crop N status, N rate prescription based on NDVI was consistently below the profitable estimated sidedress N rate.  en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis Item is protected by copyright and/or related rights. Some uses of this Item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectCornen_US
dc.subjectNitrogenen_US
dc.subjectCanopy reflectanceen_US
dc.subjectMid-Atlanticen_US
dc.titleImproving Early Season Sidedress Nitrogen Rate Prescriptions for Cornen_US
dc.typeThesisen_US
dc.contributor.departmentCrop and Soil Environmental Sciencesen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineCrop and Soil Environmental Sciencesen_US
dc.contributor.committeechairThomason, Wade Everetten_US
dc.contributor.committeememberReiter, Mark S.en_US
dc.contributor.committeememberAlley, Marcus M.en_US


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