Abstract
Abstract Field studies were conducted in 1997 and 1998 at Manhattan and Topeka, KS, to examine the competitive effects of redroot pigweed, Palmer amaranth, and common waterhemp on soybean yield. The experiments were established as a randomized complete block design in a factorial arrangement of three pigweed species, two pigweed planting dates (soybean planting and cotyledon stage), and seven weed densities (0.25, 0.5, 1, 2, 4, and 8 plants m−1 of row, plus a weed-free control). The effect of weed density on soybean yield loss, pigweed biomass, and pigweed seed production were described using a rectangular hyperbola model. Soybean yield loss varied between locations depending on the weed species, density, and time of emergence. Yield loss increased with weed density for each species and location with the first pigweed emergence time. The maximum soybean yield loss occurred at the first planting and 8 plants m−1 of row density, and was 78.7, 56.2, and 38.0% as determined by the model for Palmer amaranth, common waterhemp, and redroot pigweed, respectively. The second planting of pigweed did not significantly reduce soybean yield. The relative ranking of the pigweed species biomass was Palmer amaranth > common waterhemp > redroot pigweed. Maximum seed production for Palmer amaranth, common waterhemp, and redroot pigweed was 32,300, 51,800, and 9,500 seeds m−2. Palmer amaranth produced a larger quantity of seed than did common waterhemp or redroot pigweed at low weed densities (0.25 to 4 plants m−1 of row). But common waterhemp seed production equaled or surpassed Palmer amaranth at high weed densities. Nomenclature: Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA; common waterhemp, Amaranthus rudis Sauer AMATA; redroot pigweed, Amaranthus retroflexus L. AMARE; soybean, Glycine max (L.) Merr.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 12
Claim · model-written summary
Soybean yield loss varied between locations depending on pigweed species, density and time of emergence.
- Taxon
- Soybean
Glycine maxe0 - Interactor
- weede0weed
- Outcome
- yield losse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean yield loss varied between locations depending on the weed species, density, and time of emergence”
Claim · model-written summary
Soybean yield loss increased with pigweed density for each species and location when pigweed emerged first.
- Taxon
- soybeanGlycine maxt0
- Treatment
- weed densitye0
- Interactor
- pigweede0weed
- Outcome
- Yield losse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield loss increased with weed density for each species and location with the first pigweed emergence time”
t0“soybean”
Claim · model-written summary
Maximum soybean yield loss was 78.7% with Palmer amaranth at the first planting and 8 plants per m of row.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 8 plants m−1 of row densitye0
- Interactor
- Palmer amaranthe0weed
- Outcome
- soybean yield losse0
- Direction
- maximume0
- Value
- 78.7e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The maximum soybean yield loss occurred at the first planting and 8 plants m−1 of row density, and was 78.7, 56.2, and 38.0% as determined by the model for Palmer amaranth, common waterhemp, and redroot pigweed, respectively”
Claim · model-written summary
Maximum soybean yield loss was 56.2% with common waterhemp at the first planting and 8 plants per m of row.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 8 plants m−1 of row densitye0
- Interactor
- common waterhempe0weed
- Outcome
- soybean yield losse0
- Direction
- maximume0
- Value
- 56.2e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The maximum soybean yield loss occurred at the first planting and 8 plants m−1 of row density, and was 78.7, 56.2, and 38.0% as determined by the model for Palmer amaranth, common waterhemp, and redroot pigweed, respectively”
Claim · model-written summary
Maximum soybean yield loss was 38.0% with redroot pigweed at the first planting and 8 plants per m of row.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 8 plants m−1 of row densitye0
- Interactor
- redroot pigweede0weed
- Outcome
- soybean yield losse0
- Direction
- maximume0
- Value
- 38.0%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The maximum soybean yield loss occurred at the first planting and 8 plants m−1 of row density, and was 78.7, 56.2, and 38.0% as determined by the model for Palmer amaranth, common waterhemp, and redroot pigweed, respectively”
Claim · model-written summary
The second planting of pigweed did not significantly reduce soybean yield.
- Taxon
- soybeanGlycine maxe0
- Treatment
- second planting of pigweede0
- Interactor
- pigweede0weed
- Outcome
- soybean yielde0
- Direction
- not significantly reducee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The second planting of pigweed did not significantly reduce soybean yield”
Claim · model-written summary
Pigweed biomass ranked Palmer amaranth > common waterhemp > redroot pigweed.
Verbatim
e0“The relative ranking of the pigweed species biomass was Palmer amaranth > common waterhemp > redroot pigweed”
Claim · model-written summary
Maximum seed production of Palmer amaranth was 32,300 seeds per m2.
Verbatim
e0“Maximum seed production for Palmer amaranth, common waterhemp, and redroot pigweed was 32,300, 51,800, and 9,500 seeds m−2”
Claim · model-written summary
Maximum seed production of common waterhemp was 51,800 seeds per m2.
Verbatim
e0“Maximum seed production for Palmer amaranth, common waterhemp, and redroot pigweed was 32,300, 51,800, and 9,500 seeds m−2”
Claim · model-written summary
Maximum seed production of redroot pigweed was 9,500 seeds per m2.
Verbatim
e0“Maximum seed production for Palmer amaranth, common waterhemp, and redroot pigweed was 32,300, 51,800, and 9,500 seeds m−2”
Claim · model-written summary
At low weed densities Palmer amaranth produced more seed than common waterhemp or redroot pigweed.
Verbatim
e0“Palmer amaranth produced a larger quantity of seed than did common waterhemp or redroot pigweed at low weed densities (0.25 to 4 plants m−1 of row)”
Claim · model-written summary
At high weed densities common waterhemp seed production equaled or surpassed that of Palmer amaranth.
Verbatim
e0“common waterhemp seed production equaled or surpassed Palmer amaranth at high weed densities”
The same questions in other papers
competition · yield · Glycine max (soybean)Results differ
42 papers in the same direction as this paper · 4 in the opposite direction
- negative
- negative
- positive
43 papers more in this group
See all 47 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.