Effect of Flooding Period and Seed Burial Depth on Palmer Amaranth Seed Germination

Experiments were conducted in 2016 and 2017 in Starkville, MS to evaluate the effects of flooding period and seed burial depth on Palmer amaranth seed germination. Flood simulation was conducted with 26.5 L buckets containing 30 cm of soil plus 15 cm of water. 500 micron pore opening mesh bags measuring 64 cm² containing 20 grams of soil were used to store 100 viable Palmer amaranth seeds throughout experiment duration. Three soil textures were used, a leeper silty clay loam, a Dundee silty loam, and a Brooksville silty clay. Mesh bags were buried at 0 and 15.2 cm depth and subjected to six flooding periods, no-flooding, 1 month (October), 2 months (October-November), 3 months (October-December), 4 months (October-January), and 5 months (October-February). Following each flooding period seeds were removed from experimental area, enumerated under a microscope, and characterized as normal or damaged. Following characterization, seeds were germinated in a growth chamber under 35-30C day-night temperatures with 14-10 hours day-night period. Seeds were considered germinated when radicle was equal or longer than 1 mm. Data were subjected to analysis of variance using PROC GLM procedure in SAS^® Software v. 9.4 and means were separated using Fisher’s Protected LSD at α=0.05. Results show that flooding period significantly reduced Palmer amaranth seed germination, regardless of flooding period. Seed burial depth did not affect Palmer amaranth germination under flooding conditions.