Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 12, 2001
Publication Date: N/A
Technical Abstract: Experiments were conducted to study the effect of soil amendments, depth and time on seed survival of common lambsquarters and fall panicum. Steam sterilized soil was sieved with 0.5 mm sieve to remove larger debris and was amended with freshly collected cow manure (1%), finished compost (1% by weight), fresh alfalfa (3.4%) and brassica (3.6%) plants cut to 1 cm length and mixed well with the soil. Field experiments were conducted during December 1998 to December 1999. Eight hundred g of sieved soil mixed with amendments and 200 seeds each of lambsquarters and fall panicum was packed into double layered panty hose, moistened, placed in trenches of 2 cm (shallow) and 20 cm (deep) covered evenly with soil and flagged. Samples were collected at Dec. 9, Mar. 9, May 25, Sept. 24 and Dec. 9. Samples were spread in shallow plastic trays for three weeks to estimate emergence in amended soil. After three weeks soils were dried, sieved through 0.6 mm sieves, washed, seeds were identified and counted by species. Collected seeds were spread in petri dishes to determine germination in the absence of amendments. Remaining seeds were pressed with fine tipped forceps to determine viability. Number of viable seeds decreased with time and overall annual loss rate was 13% and 22% for common lambsquarters and fall panicum, respectively. Emergence from soil was highest for common lambsquarters (29%) and fall panicum (48%) at the March removal date and declined at subsequent dates. Conversely, seed dormancy was lowest at the March removal date and increased thereafter for both species. Soil amendments did not show any consistent significant effect on viability, emergence or dormancy of both common lambsquarters and fall panicum.