Effect of tillage and corn row spacing on common waterhemp growth and fecundity

dc.contributor.author Nordby, Dawn
dc.contributor.department Agronomy
dc.date 2020-07-17T07:21:29.000
dc.date.accessioned 2021-02-26T08:32:16Z
dc.date.available 2021-02-26T08:32:16Z
dc.date.copyright Wed Jan 01 00:00:00 UTC 2003
dc.date.issued 2003-01-01
dc.description.abstract <p>The acceptance of integrated weed management programs has been hindered by a lack of information on crop-weed interactions. Four experiments were conducted in central Iowa during 2001 and 2002 in corn planted in 38 and 76 cm rows to determine the response of common waterhemp (Amaranthus rudis Sauer) growth parameters to corn (Zea mays) row spacing and date of common waterhemp emergence. Four common waterhemp emergence cohorts were established in each experiment corresponding to the VE, V3, V5, and V8 stages of corn (Zea mays) development. Delayed emergence of common waterhemp in corn significantly affected all growth parameters of common waterhemp. Common waterhemp survival averaged 80, 44, 3, and 1% survival for the first, second, third and fourth cohorts respectively. Mature common waterhemp height for the first cohort was 140 cm, whereas plants emerging at the V8 corn stage were only 5 cm. Corn row spacing significantly affected biomass and fecundity of the first cohort, but later cohorts were not affected by row spacing. Biomass of the first cohort was 20% less in 38 cm rows than in 76 cm rows. Biomass and seed production of waterhemp emerging at the V3, V5, and V8 corn stages decreased 80, 97 and 99%, respectively in comparison to the first cohort. Field studies were conducted in 2001 and 2002 to evaluate the influence of tillage on common waterhemp (Amaranthus rudis Sauer) seedbank behavior. Emergence of common waterhemp was greater in no-till than chisel till. Tillage did not affect the initial time of emergence; however, the time to 50% emergence was longer in no-till than chisel till. Duration of emergence did not differ among tillage systems. Common waterhemp seed was concentrated near the soil surface in no-till, whereas seed in the chisel till were primarily found between 9 and 15 cm. The delayed and increased emergence in no-till contributes to the problems in managing common waterhemp in this system.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/19525/
dc.identifier.articleid 20524
dc.identifier.contextkey 18549552
dc.identifier.doi https://doi.org/10.31274/rtd-20200716-92
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/19525
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/96892
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/19525/Nordby_ISU_2003_N67.pdf|||Fri Jan 14 21:57:31 UTC 2022
dc.subject.keywords Agronomy
dc.subject.keywords Crop production and physiology (Weed science)
dc.subject.keywords Weed science
dc.title Effect of tillage and corn row spacing on common waterhemp growth and fecundity
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication fdd5c06c-bdbe-469c-a38e-51e664fece7a
thesis.degree.discipline Crop Production and Physiology (Weed Science)
thesis.degree.level thesis
thesis.degree.name Master of Science
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