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Development of Nitrogen rate Recommendations for No-till Dryland Grain Sorghum in Virginia

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dc.contributor.authorKhosla, Rajiven
dc.contributor.committeechairAlley, Marcus M.en
dc.contributor.committeememberBrann, Daniel E.en
dc.contributor.committeememberDe Datta, Surajit K.en
dc.contributor.committeememberDillaha, Theo A. IIIen
dc.contributor.committeememberMartens, David C.en
dc.contributor.committeememberZelazny, Lucian W.en
dc.contributor.departmentCrop and Soil Environmental Sciencesen
dc.date.accessioned2014-03-14T20:17:18Zen
dc.date.adate1998-11-12en
dc.date.available2014-03-14T20:17:18Zen
dc.date.issued1998-10-26en
dc.date.rdate1999-11-12en
dc.date.sdate1998-10-12en
dc.description.abstractLittle research has been done in the humid mid-Atlantic region to develop full-season N fertilizer recommendations for dryland no-tillage grain sorghum (Sorghum bicolor L. Moench) production. The objectives of this study were: (i) to determine the optimum rate of band-placed starter N fertilizer needed in combination with side-dress N applications to achieve economic grain yields, (ii) to investigate if pre-plant broadcast N applications are as efficient as band-placed plus side-dress N applications, (iii) to evaluate the response of grain sorghum yield to partitioned side-dress N applications, and (iv) to study the influence of residual soil profile mineral-N (nitrate and ammonium) on sorghum response to applied N fertilization. Multi-location field studies were conducted over three years. A range of N treatments of various starter-band and side-dress N rates were applied. The experimental data indicate that an optimum rate of N fertilization depends on residual soil mineral-N. Little or zero starter-band-N in conjunction with side-dress-N applications of 130 kg of N ha-1 for soils testing high in mineral-N ( 50 kg N ha-1 in the top 0.3m of surface soil) at planting, and a starter-band-N supplement of 40 kg N ha-1 in conjunction with 130 kg N ha-1 side-dress N for soils testing low in mineral-N at planting, optimized the grain sorghum yields in these experiments. Broadcast N applications were observed to be as efficient as band placed N applications when followed by rainfall soon after application. Grain sorghum yields did respond to the partitioned side-dress N applications. However, partitioning of side-dress N application again depends on the residual mineral-N level present in the soil. In order to consider residual soil mineral-N in making N fertilizer recommendations "Associated Nitrogen Fertilizer Equivalency" (ANFE) values were calculated. ANFE is the amount of applied N that has potential to produce the same yield as that produced by the residual soil mineral-N. The N fertilizer recommendations based on ANFE values were quite close for two out of four sites as compared to the N rates at which the maximum yields were obtained in this study.en
dc.description.degreePh. D.en
dc.identifier.otheretd-101198-103006en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-101198-103006/en
dc.identifier.urihttp://hdl.handle.net/10919/29249en
dc.publisherVirginia Techen
dc.relation.haspartApendixC.pdfen
dc.relation.haspartApendixD.pdfen
dc.relation.haspartApendixE.pdfen
dc.relation.haspartvita.pdfen
dc.relation.haspartApendixI.pdfen
dc.relation.haspartApendixJ.pdfen
dc.relation.haspartApendixG.pdfen
dc.relation.haspartApendixH.pdfen
dc.relation.haspartApendixF.pdfen
dc.relation.haspartApendixB.pdfen
dc.relation.haspartApendixA.pdfen
dc.relation.haspartchapter5.pdfen
dc.relation.haspartchapter4.pdfen
dc.relation.haspartchapter3.pdfen
dc.relation.haspartchapter2.pdfen
dc.relation.haspartchapter1.pdfen
dc.relation.hasparttables.pdfen
dc.relation.haspartfigures.pdfen
dc.relation.hasparttoc.pdfen
dc.relation.haspartack.pdfen
dc.relation.haspartdedicate.pdfen
dc.relation.haspartAbstract.pdfen
dc.relation.hasparttitlepge.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectSide-dressen
dc.subjectSoil mineral-Nen
dc.subjectSorghumen
dc.subjectNitrogenen
dc.subjectBroadcasten
dc.subjectStarter-band.en
dc.titleDevelopment of Nitrogen rate Recommendations for No-till Dryland Grain Sorghum in Virginiaen
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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