Abstract
Abstract Redroot pigweed ( Amaranthus retroflexus L.) and slender amaranth ( Amaranthus viridis L.) are considered emerging problematic weeds in summer crops in Australia. An outdoor pot experiment was conducted to examine the effects of planting time on two populations of A. retroflexus and A. viridis at the research farm of the University of Queensland, Australia. Both species were planted every month from October to January (2017 to 2018 and 2018 to 2019), and their growth and seed production were recorded. Although both weeds matured at a similar number of growing degree days (GDD), they required a different number of days to complete their life cycles depending on planting date. The growth period was reduced and flowering occurred sooner as both species experienced cooler temperatures and shorter daylight hours. Both species exhibited increased height, biomass, and seed production for the October-sown plants compared with other planting times, and these parameters were reduced by delaying the planting time. The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations) was reduced by more than 70% and 65%, respectively, when planted in January, in comparison to planting in October. When planted in October, A. retroflexus and A. viridis produced 11,350 and 5,780 seeds plant −1 , but these were reduced to 770 and 365 seeds plant −1 for the January planting date, respectively. Although the growth and fecundity of these species were dependent on planting time, these weeds could emerge throughout the late spring to summer growing season (October to March) in southeast Australia and could produce a significant number of seeds. The results showed that when these species emerged in the late spring (October), they grew vigorously and produced more biomass in comparison with the other planting dates. Therefore, any early weed management practice for these species could be beneficial for minimizing the subsequent cost and energy inputs toward their control.
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Claims 14
Claim · model-written summary
Both amaranths matured at similar growing degree days.
- Taxon
- Amaranthus retroflexus L.
Amaranthus retroflexuse1 - Outcome
- matured at a similar number of growing degree days (GDD)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although both weeds matured at a similar number of growing degree days (GDD)”
e1“Amaranthus retroflexus L.”
Claim · model-written summary
Planting date changed days to complete life cycles.
- Taxon
- Amaranthus retroflexus L.Amaranthus retroflexuse1
- Treatment
- planting datee0
- Outcome
- number of days to complete their life cyclese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“they required a different number of days to complete their life cycles depending on planting date.”
e1“Amaranthus retroflexus L.”
Claim · model-written summary
Cooler temperatures and shorter days shortened the growth period.
- Taxon
- Amaranthus retroflexus L.Amaranthus retroflexuse1
- Treatment
- cooler temperatures and shorter daylight hourse0
- Outcome
- growth periode0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The growth period was reduced and flowering occurred sooner as both species experienced cooler temperatures and shorter daylight hours.”
e1“Amaranthus retroflexus L.”
Claim · model-written summary
Cooler temperatures and shorter days advanced flowering.
- Taxon
- Amaranthus retroflexus L.Amaranthus retroflexuse1
- Treatment
- cooler temperatures and shorter daylight hourse0
- Outcome
- floweringe0
- Direction
- soonere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The growth period was reduced and flowering occurred sooner as both species experienced cooler temperatures and shorter daylight hours.”
e1“Amaranthus retroflexus L.”
Claim · model-written summary
October-sown A. retroflexus had greater height, biomass and seed production than later sowings.
- Taxon
- A. retroflexusAmaranthus retroflexuse1
- Treatment
- October-sowne0
- Outcome
- height, biomass, and seed productione0
- Direction
- increasede0
- Comparator
- other planting timese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both species exhibited increased height, biomass, and seed production for the October-sown plants compared with other planting times”
e1“The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations)”
Claim · model-written summary
October-sown A. viridis had greater height, biomass and seed production than later sowings.
- Taxon
- A. viridis
Amaranthus viridise1 - Treatment
- October-sowne0
- Outcome
- height, biomass, and seed productione0
- Direction
- increasede0
- Comparator
- other planting timese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both species exhibited increased height, biomass, and seed production for the October-sown plants compared with other planting times”
e1“The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations)”
Claim · model-written summary
January sowing reduced A. retroflexus shoot and root biomass by over 70%.
- Taxon
- A. retroflexusAmaranthus retroflexuse0
- Treatment
- planted in Januarye0
- Outcome
- shoot and root biomasse0
- Direction
- reducede0
- Value
- more than 70%e0
- Comparator
- planting in Octobere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations) was reduced by more than 70% and 65%, respectively, when planted in January, in comparison to planting in October.”
Claim · model-written summary
January sowing reduced A. viridis shoot and root biomass by 65%.
- Taxon
- A. viridisAmaranthus viridise0
- Treatment
- planted in Januarye0
- Outcome
- shoot and root biomasse0
- Direction
- reducede0
- Value
- 65%e0
- Comparator
- planting in Octobere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations) was reduced by more than 70% and 65%, respectively, when planted in January, in comparison to planting in October.”
Claim · model-written summary
October-sown A. retroflexus produced 11,350 seeds per plant.
- Taxon
- A. retroflexusAmaranthus retroflexuse0
- Outcome
- seeds plant −1e0
- Value
- 11,350e0
- Qualifier
- planted in Octobere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When planted in October, A. retroflexus and A. viridis produced 11,350 and 5,780 seeds plant −1”
Claim · model-written summary
October-sown A. viridis produced 5,780 seeds per plant.
- Taxon
- A. viridisAmaranthus viridise0
- Outcome
- seeds plant −1e0
- Value
- 5,780e0
- Qualifier
- planted in Octobere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When planted in October, A. retroflexus and A. viridis produced 11,350 and 5,780 seeds plant −1”
Claim · model-written summary
January-sown A. retroflexus produced 770 seeds per plant.
- Taxon
- A. retroflexusAmaranthus retroflexuse1
- Treatment
- January planting datee0
- Outcome
- seeds plant −1e0
- Direction
- reducede0
- Value
- 770e0
- Comparator
- Octobere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but these were reduced to 770 and 365 seeds plant −1 for the January planting date, respectively.”
e1“When planted in October, A. retroflexus and A. viridis”
Claim · model-written summary
January-sown A. viridis produced 365 seeds per plant.
- Taxon
- A. viridisAmaranthus viridise1
- Treatment
- January planting datee0
- Outcome
- seeds plant −1e0
- Direction
- reducede0
- Value
- 365e0
- Comparator
- Octobere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but these were reduced to 770 and 365 seeds plant −1 for the January planting date, respectively.”
e1“When planted in October, A. retroflexus and A. viridis”
Claim · model-written summary
These weeds can emerge October to March in southeast Australia and produce many seeds.
- Taxon
- A. retroflexus and A. viridisAmaranthus viridisAmaranthus retroflexuse1
- Outcome
- emerge throughout the late spring to summer growing season (October to March)e0
- Setting
- southeast Australiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“these weeds could emerge throughout the late spring to summer growing season (October to March) in southeast Australia and could produce a significant number of seeds.”
e1“The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations)”
Claim · model-written summary
The authors recommend early weed management to reduce later control costs and inputs.
- Taxon
- A. retroflexus and A. viridisAmaranthus viridisAmaranthus retroflexuse1
- Outcome
- early weed management practicee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“any early weed management practice for these species could be beneficial for minimizing the subsequent cost and energy inputs toward their control.”
e1“The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations)”
The same questions in other papers
sowing time · growth · Amaranthus retroflexus (redroot amaranth)Positive and negative results
1 in the opposite direction
- negative
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.