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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Weed Management Systems for Organic and Conventional Crops of the Southeastern Coastal Plain

Location: Crop Protection and Management Research

Title: Palmer amaranth seed mortality in response to burial depth and time

item Sosnoskie, L.M -
item Culpepper, A.S. -
item Webster, Theodore

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: February 22, 2011
Publication Date: May 1, 2011
Citation: Sosnoskie, L., Culpepper, A., Webster, T.M. 2011. Palmer amaranth seed mortality in response to burial depth and time. National Cotton Council Beltwide Cotton Conference. 1550-1552.

Technical Abstract: Glyphosate resistant Palmer amaranth infests millions of arable acres in the SE US. One proposed method of reducing population numbers is to bury surface seeds deeply, below their optimal emergence zone. The objective of this study was to determine how burial longevity and depth impact Palmer amaranth seed viability. Glyphosate-susceptible (GLY-S) and -resistant (GLY-R) Palmer amaranth seed were buried at depths of 0.5, 1, 4 and 16 inches for up to 30 months starting in January of 2008 and 2009. Four replications of each biotype by depth combination were exhumed at regular (3 to 6 month) intervals and the recovered seed germinated at 30 C. Seed longevity was significantly affected by burial length and depth, but not biotype. Seed viability decreased as time of burial increased. Averaged over depth, seed viability was approximately 60% after 12 months of burial; after two years, viability had decreased to below 40%. Seed longevity increased with burial depth; averaged over time, seed buried at 0.5, 1, 4 and 16 inches were 50, 55, 60, and 70% viable, respectively. Results from this study indicate that buried Palmer amaranth seeds will decay with time and that the seedbank is likely ephemeral. Growers that deep till their fields with the intention of reducing seedbank size should wait several years before repeating the practice to ensure that deeply buried seeds have decayed.

Last Modified: 10/31/2014
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