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Continuous No-till Management: Implications for Soil Quality, Carbon Sequestration, and Nitrogen Conservation

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dc.contributor.authorSpargo, John T.en
dc.contributor.committeechairAlley, Marcus M.en
dc.contributor.committeememberEvanylo, Gregory K.en
dc.contributor.committeememberFollett, Ronald F.en
dc.contributor.committeememberPhillips, Steven B.en
dc.contributor.committeememberZelazny, Lucian W.en
dc.contributor.departmentCrop and Soil Environmental Sciencesen
dc.date.accessioned2014-03-14T20:07:17Zen
dc.date.adate2008-03-04en
dc.date.available2014-03-14T20:07:17Zen
dc.date.issued2008-02-01en
dc.date.rdate2008-03-04en
dc.date.sdate2008-02-10en
dc.description.abstractNo-till management for agronomic crop production is recognized as an effective practice to regain a portion of soil organic matter lost following decades of cultivation. Increasing soil organic matter sequesters C, conserves organic N and concomitantly improves soil quality. Objectives of this research were to: i) quantify C sequestration rate and N conservation with duration of continuous no-till; ii) measure C stratification with continuous no-till as an indicator of soil quality; and iii) evaluate the Illinois soil N test (ISNT) for its value to predict fertilizer N needs of corn in Virginia. Objectives i and ii were achieved by collecting soil samples from 63 production fields in the Virginia Coastal Plain that were managed using continuous no-till from 0 to 14 yrs. No-till management resulted in sequestration of 0.308 ± 0.280 Mg C ha⁻¹ y⁻¹ and conservation of 22.2 ± 21.2 kg N ha⁻¹ yr⁻¹ (0-15 cm). The C stratification ratio (0-2.5 cm: 7.5-15 cm) increased with increasing duration of continuous no-till (0.133 ± 0.056 yr⁻¹) due to the accumulation of organic matter at the soil surface indicating improved soil quality with continuous no-till management. Objective iii was addressed by conducting 29 on-farm fertilizer N response trials in major corn producing areas of Virginia with the duration of continuous no-till management ranging from 0 to 25 yrs. The ISNT values were significantly related to yield without fertilizer N (r² = 0.57; p<0.001) and relative yield (r² = 0.64; p<0.0001). We also found that the ISNT extracted a relatively consistent percentage of total soil N (16.3 ± 0.73 %) suggesting it is a poor indicator of labile N. Total soil N values did almost as well as the ISNT in predicting yield without fertilizer N (r² = 0.53; p = 0.0002), and equally well predicting relative yield (r² = 0.64; p<0.0001). Results do not suggest the ISNT is useful for measuring mineralizalbe N or improving fertilizer N recommendations in Virginia cropping systems.en
dc.description.degreePh. D.en
dc.identifier.otheretd-02102008-174038en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-02102008-174038/en
dc.identifier.urihttp://hdl.handle.net/10919/26166en
dc.publisherVirginia Techen
dc.relation.haspartJSpargo.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectNitrogen use efficiencyen
dc.subjectcarbon tradingen
dc.subjectnutrient tradingen
dc.subjectsoil organic matteren
dc.titleContinuous No-till Management: Implications for Soil Quality, Carbon Sequestration, and Nitrogen Conservationen
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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