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dc.contributor.advisorBond, Jason A.en_US
dc.contributor.authorLawrence, Benjaminen_US
dc.date.accessioned2019-07-16T22:05:37Zen_US
dc.date.available2019-07-16T22:05:37Zen_US
dc.date.issued2019
dc.identifier.urihttps://hdl.handle.net/11668/14539en_US
dc.description.abstractResearch was conducted at the Mississippi State University Delta Research and Extension Center from 2015 to 2018 to (1) determine the effects of sub-lethal concentrations of paraquat, metribuzin, fomesafen, and cloransulam-methyl applied at different rice growth stages, determine the effects on rice growth of simulated off-target paraquat applications at varying concentration based on a proportionally decreased carrier volume characterize rice response to a sub-lethal concentration of paraquat in combination with common POST and residual herbicides, assess whether starter N fertilizer or different N fertilizer management strategies can aide in rice recover after exposure to a sub-lethal concentration of paraquat, and define a maximum soil concentration of S-metolachlor that will allow rice to germinate and emerge. Rice yield was negatively affected following exposure to paraquat applied any time after rice emergence. Paraquat applications to rice in early reproductive growth reduced rough rice yield and seed germination the greatest. Paraquat plus metribuzin injured rice 68 to 69% 14 and 28 d after treatment (DAT), which was 10 to 13% greater than following paraquat alone or paraquat plus fomesafen. Pooled across metribuzin and fomesafen treatments, paraquat reduced rough rice yields 23%. Paraquat plus 10 different residual herbicides injured rice ≥51% 28 DAT and reduced rough rice yields ≥21%. In spite of starter N fertilizer applications, paraquat injured rice ≥41%, reduced height 57%, reduced dry weight prior to flooding 77%, delayed maturity 10 d, reduced dry weight at maturity 33%, and reduced rough rice yield 35%. Similar results were observed in the N Fertilizer Timing Study. Soil concentrations of s-metolachlor 28 DAT were 30, 31, 32, 36, 61, and 488 ppm following exposure to s-metolachlor applied at 0, 1/64, 1/32, 1/16, 1/4, and 1X concentration. A soil analysis would be the best option to determine levels of s-metolachlor prior to planting rice if an off-target herbicide movement containing s-metolachlor occurred. These data indicate that paraquat can have negative impact on rice growth and development. Therefore, it is crucial that if environmental conditions are conducive for off-target herbicide movement extreme caution should be exercised when applying paraquat adjacent to fields devoted to rice production.en_US
dc.language.isoen_USen_US
dc.publisherMississippi State Universityen_US
dc.subjectriceen_US
dc.subjectparaquaten_US
dc.subjectapplication timingen_US
dc.subjectoff-targeten_US
dc.subjectherbicide mixtureen_US
dc.subjectresidual herbicideen_US
dc.subjectnitrogenen_US
dc.titleRice (Oryza sativa) response and management following exposure to sub-lethal rates of non-target herbicidesen_US
dc.typeDissertationen_US
dc.publisher.departmentDepartment of Plant and Soil Sciencesen_US
dc.publisher.collegeCollege of Agriculture and Life Scienceen_US
dc.publisher.researchcenterDelta Research and Extension Centeren_US
dc.rights.embargo7/16/2020en_US
dc.source.institutionMississippi State Universityen_US
dc.subject.degreeDoctor of Philosophyen_US
dc.subject.majorWeed Scienceen_US
dc.contributor.committeeGolden, Bobby R.en_US
dc.contributor.committeeAllen Jr., Thomas W.en_US
dc.contributor.committeeReynolds, Daniel B.en_US
dc.contributor.committeeBararpour, M. T.en_US
dc.contributor.committeeCox, Michael S.en_US
dc.contributor.committeeDodds, Darrin M.en_US
dc.contributor.committeeHopper, Georgeen_US


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