Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 6, 1997
Publication Date: N/A
Technical Abstract: Field research was conducted at Rosemount, MN in 1994 and 1995 to determine the effect of tillage in the dark on the emergence of annual weed species under uniform soil and environmental conditions. The experiment was conduced in a weed nursery with 13 annual weed species grown individually in 5-m-wide strips. The entire experimental area was moldboard plowed the previous fall. Secondary tillage was conducted in mid- and late-May with a tandem disk operated 8 cm deep. Secondary tillage treatments included: two passes with the disk in the light, one pass in the light followed by the second pass in the dark, two passes in the dark and no secondary tillage with glyphosate to control emerged weeds. Tillage operations in the light were conducted between 2:00 and 4:00 p.m. and dark operations were conducted between 11:00 p.m. and midnight. Emergence of annual grass species was not affected by secondary tillage methods. Emergence of large-seeded broadleaf species, giant ragweed, and velvetleaf was similar following tillage in the light or dark. However, total emergence of the large-seeded species was often less when glyphosate replaced secondary tillage. Emergence of small-seeded broadleaf species, common ragweed, eastern black nightshade, pigweed species, Pennsylvania smartweed, and wild mustard was affected by the time of secondary tillage. Emergence reduction for small-seeded broadleaf species varied by tillage date and species and ranged from 30 to 80%. Replacing tillage with glyphosate often resulted in reductions in emergence similar to those observed with tillage in the dark.