Winter Barley as a Commodity Cover Crop in the Mid-Atlantic Coastal Plain and Evaluation of Soft Red Winter Wheat Nitrogen Use Efficiency by Genotype, and its Prediction of Nitrogen Use Efficiency through Canopy Spectral Reflectance in the Eastern US

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dc.contributor.authorPavuluri, Kiranen
dc.contributor.committeechairThomason, Wade E.en
dc.contributor.committeememberGriffey, Carl A.en
dc.contributor.committeememberBalota, Mariaen
dc.contributor.committeememberReiter, Mark S.en
dc.contributor.departmentCrop and Soil Environmental Sciencesen
dc.date.accessioned2014-04-09T22:22:40Zen
dc.date.available2014-04-09T22:22:40Zen
dc.date.issued2014-01-10en
dc.description.abstractTo understand the impact of N management on harvestable cover crop systems, seven research trials compared: 1) standard intensive management (SIM) (both fall and spring N application), 2) No fall N, a single spring N application, and 3) Cover N (no N application) effects on winter barley (Hordeum vulgare L.) plant biomass (PB), plant N uptake (PNU), grain yield, residual soil nitrate (RSN), and ammonium (RSA). In general, at winter dormancy, SIM resulted in increased PB and PNU but not RSN or RSA. At cover crop termination; SIM and the No fall N practices increased PNU, and at harvesting stage; they produced higher grain yields than the Cover N practice with little significant effect on RSN or RSA values, under normal climatic conditions. While overall yields for the No fall N treatment were lower (8%) than SIM yields, partial net return was similar due to decreased fertilizer input. Nitrogen use efficiency (NUE) of soft red winter wheat (SRWW) can be improved by characterizing genotypes for NUE using canopy spectral reflectance [(CSR), a cheap, rapid and non-destructive remote sensing tool]. The other objectives of this study were to evaluate the predictive potential of vegetative reflection indices for wheat nitrogen use efficiency (NUE) by genotype and the appropriate stages of CSR sensing. An elite panel of 281 regionally developed SRWW genotypes was screened under low and normal N regimes in two crop seasons for grain yield, N uptake, nitrogen use efficiency for yield (NUEY) and nitrogen use efficiency for protein (NUEP). The best models incorporating CSR data at wheat heading explained a significant proportion of total variation in grain yield, N uptake, NUEY and NUEP. Based on the best linear unbiased predictor values, genotypes were ranked and grouped into quartiles and the most efficient and responsive genotypes were identified. A significant proportion of the genotypes with high NUEY under high N conditions also had high NUEY under N stress; however, this was not the case for NUEP. Similarly, a significant proportion of genotypes with high NUEY also had high NUEP under both normal and low N conditions.en
dc.description.degreePh. D.en
dc.format.mediumETDen
dc.identifier.othervt_gsexam:1993en
dc.identifier.urihttp://hdl.handle.net/10919/47103en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectwheaten
dc.subjectbarleyen
dc.subjectcover cropsen
dc.subjectNitrogenen
dc.subjectcanopy spectral reflectanceen
dc.titleWinter Barley as a Commodity Cover Crop in the Mid-Atlantic Coastal Plain and Evaluation of Soft Red Winter Wheat Nitrogen Use Efficiency by Genotype, and its Prediction of Nitrogen Use Efficiency through Canopy Spectral Reflectance in the Eastern USen
dc.typeDissertationen
thesis.degree.disciplineCrop and Soil Environmental Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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