Field experiments were conducted from 1979 to 1989 to determine the influence of conventional, reduced, and no-tillage systems and different herbicide combinations on weed species and population, weed control, and soybean injury, population, and yield. In no-till (NT) non-treated plots, there was an abrupt shift from horseweed as the dominant early spring emerging weed to gray goldenrod in 1985. Following its initial observation, gray goldenrod became the dominant species within 2 yr, with giant foxtail as the only other species observed in these plots. Giant foxtail was the dominant weed species from 1980 to 1989 in conventional till (CT) and reduced-till (RT) plots. There also was a shift in the frequency of occurrence and in density of several broadleaf weed species during the 1 1-yr study. Most herbicides provided excellent control of all weeds in all tillage systems, especially those that included POST herbicides. There was little difference between glyphosate and paraquat in controlling weeds present at the time of planting in NT. PRE herbicides caused 2 to 9% soybean injury with slightly greater injury occurring in CT and RT than in NT. The POST broadleaf herbicides did not significantly increase soybean injury. There were no differences in soybean population or yield among the herbicide treatments regardless of tillage. There also was no difference in soybean population or yield in NT compared with CT when averaged over all herbicide treatments. Nomenclature: Glyphosate, N-(phosphonomethyl)glycine; paraquat, 1,1'-dimethyl-4,4'-bipyridinium ion; soybean, Glycine max (L.) Merr. 'Williams 82'; giant foxtail, Setaria faberi Herrm. #3 SETFA; gray goldenrod, Solidago nemoralis Ait. # SOONE; horseweed, Conyza canadensis (L.) Cronq. # ERICA. Additional index words: Minimum tillage, conservation tillage, Setariafaberi, Solidago nemoralis, Conyza canadensis, ERICA, SETFA, SOONE.
[1]
W. Dick,et al.
Continuous Tillage and Rotation Combinations Effects on Corn, Soybean, and Oat Yields1
,
1985
.
[2]
R. Cruse,et al.
Tillage system effects on crop growth and production costs for a corn-soybean rotation.
,
1989
.
[3]
W. Wilhelm,et al.
Corn and Soybean Yield Response to Crop Residue Management Under No‐Tillage Production Systems1
,
1986
.
[4]
E. S. Oplinger,et al.
Influence of Tillage Systems on Annual Weed Densities and Control in Solid-seeded Soybean (Glycine max)
,
1990,
Weed Science.
[5]
G. Kapuśta.
Seedbed Tillage and Herbicide Influence on Soybean (Glycine max) Weed Control and Yield
,
1979,
Weed Science.
[6]
J. A. Stuedemann,et al.
Effect of Three Weed Control Regimes on No-Till and Tilled Soybeans (Glycine max)
,
1984,
Weed Science.
[7]
A. D. Worsham,et al.
Combinations of Nonselective Herbicides for Difficult to Control Weeds in No-Till Corn, Zea mays, and Soybeans, Glycine max
,
1988,
Weed Science.
[8]
J. Cardina,et al.
Long-Term Tillage Effects on Seed Banks in Three Ohio Soils
,
1991,
Weed Science.
[9]
W. G. Lovely,et al.
Effect of Plant Residue on Herbicide Performance in No-Tillage Corn
,
1975,
Weed Science.
[10]
M. A. Wrucke,et al.
Weed Species Distribution as Influenced by Tillage and Herbicides
,
1985,
Weed Science.
[11]
M. Gebhardt,et al.
Interrelations of Tillage and Weed Control for Soybean (Glycine max) Production
,
1987,
Weed Science.