Abstract
The impact of two weed management systems on the weed seed reserves of the soil, on the yearly weed problem, and on corn ( Zea mays L.) production was assessed where corn was grown under furrow irrigation for 6 consecutive years. In one system, 2.2 kg/ha of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)- s -triazine] was applied annually to the same plots as a preemergence treatment. In the other system, a mixture of 1.7 kg/ha of atrazine plus 2.2 kg/ha of alachlor [2-chloro-2′,6′-diethyl- N -(methoxymethyl)acetanilide] was applied preemergence, followed by a postemergence application of 0.6 kg/ha of the alkanolamine salts of 2,4-D [(2,4-dichlorophenoxy)acetic acid]. The response of weeds and corn is presented only where atrazine was applied annually because the results were similar between both weed management systems. Weed seeds from eight annual species were identified, with redroot pigweed ( Amaranthus retroflexus L. ♯ AMARE) and common lambsquarters ( Chenopodium album ♯ CHEAL) comprising 82 and 12%, respectively, of the initial 1.3 billion weed seeds/ha that were present in the upper 25 cm of the soil profile. After the sixth cropping year, the overall decline in the total number of redroot pigweed and common lambsquarters seeds was 99 and 94%, respectively. Very few weeds produced seeds during the first 5 yr, and no weed seeds were produced during the sixth year where atrazine was applied annually. When the use of atrazine was discontinued on one-half of each plot at the beginning of the fourth year, the weed seed reserve in soil began to increase due to an increase in the weed population. After 3 yr of not using atrazine, the weed seed reserve in soil had built up to over 648 million seeds/ha, and was then within 50% of the initial weed seed population. In the fifth and sixth years, grain yields were reduced 39 and 14%, respectively, where atrazine had been discontinued after 3 yr.
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 13
Claim · model-written summary
The two weed management systems had similar results.
- Taxon
- corn
Zea mays subsp. mayst0 - Outcome
- results were similar between both weed management systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the results were similar between both weed management systems.”
t0“Corn(Zea mays)”
Claim · model-written summary
Redroot pigweed comprised 82% of the initial weed seed reserve.
- Taxon
- cornZea mays subsp. mayst0
- Interactor
- redroot pigweede0weed
- Outcome
- redroot pigweede0
- Value
- 82e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“redroot pigweed ( Amaranthus retroflexus L. ♯ AMARE) and common lambsquarters ( Chenopodium album ♯ CHEAL) comprising 82 and 12%, respectively, of the initial 1.3 billion weed seeds/ha”
t0“Corn(Zea mays)”
Claim · model-written summary
Common lambsquarters comprised 12% of the initial weed seed reserve.
- Taxon
- cornZea mays subsp. mayst0
- Interactor
- common lambsquarters
Chenopodium albume0weed - Outcome
- common lambsquarterse0
- Value
- 12%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“redroot pigweed ( Amaranthus retroflexus L. ♯ AMARE) and common lambsquarters ( Chenopodium album ♯ CHEAL) comprising 82 and 12%, respectively, of the initial 1.3 billion weed seeds/ha”
t0“Corn(Zea mays)”
Claim · model-written summary
The initial weed seed reserve was 1.3 billion seeds/ha in the upper 25 cm of soil.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- weed seedse0
- Value
- 1.3 billion weed seeds/hae0
- Qualifier
- upper 25 cm of the soil profilee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the initial 1.3 billion weed seeds/ha that were present in the upper 25 cm of the soil profile.”
t0“Corn(Zea mays)”
Claim · model-written summary
After six cropping years, redroot pigweed seed number declined 99%.
- Taxon
- cornZea mays subsp. mayst0
- Interactor
- redroot pigweede0weed
- Outcome
- redroot pigweede0
- Direction
- declinee0
- Value
- 99e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After the sixth cropping year, the overall decline in the total number of redroot pigweed and common lambsquarters seeds was 99 and 94%, respectively.”
t0“Corn(Zea mays)”
Claim · model-written summary
After six cropping years, common lambsquarters seed number declined 94%.
- Taxon
- cornZea mays subsp. mayst0
- Interactor
- common lambsquartersChenopodium albume0weed
- Outcome
- common lambsquarters seedse0
- Direction
- declinee0
- Value
- 94%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After the sixth cropping year, the overall decline in the total number of redroot pigweed and common lambsquarters seeds was 99 and 94%, respectively.”
t0“Corn(Zea mays)”
Claim · model-written summary
Very few weeds produced seeds during the first five years of annual atrazine use.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- atrazine was applied annuallye0
- Outcome
- Very few weeds produced seedse0
- Qualifier
- first 5 yre0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Very few weeds produced seeds during the first 5 yr, and no weed seeds were produced during the sixth year where atrazine was applied annually.”
t0“Corn(Zea mays)”
Claim · model-written summary
No weed seeds were produced in year six under annual atrazine.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- atrazine was applied annuallye0
- Outcome
- no weed seeds were producede0
- Qualifier
- sixth yeare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Very few weeds produced seeds during the first 5 yr, and no weed seeds were produced during the sixth year where atrazine was applied annually.”
t0“Corn(Zea mays)”
Claim · model-written summary
Discontinuing atrazine in year four allowed the soil weed seed reserve to increase with weed population.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- use of atrazine was discontinuede0
- Outcome
- weed seed reserve in soile0
- Direction
- increasee0
- Qualifier
- beginning of the fourth yeare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When the use of atrazine was discontinued on one-half of each plot at the beginning of the fourth year, the weed seed reserve in soil began to increase due to an increase in the weed population.”
t0“Corn(Zea mays)”
Claim · model-written summary
After three years without atrazine, soil weed seed reserve exceeded 648 million seeds/ha.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- weed seed reserve in soile0
- Direction
- built upe0
- Value
- over 648 million seeds/hae0
- Qualifier
- After 3 yr of not using atrazinee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 3 yr of not using atrazine, the weed seed reserve in soil had built up to over 648 million seeds/ha, and was then within 50% of the initial weed seed population.”
t0“Corn(Zea mays)”
Claim · model-written summary
After three years without atrazine, the reserve was within 50% of its initial population.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- weed seed reserve in soile0
- Value
- within 50%e0
- Comparator
- initial weed seed populatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 3 yr of not using atrazine, the weed seed reserve in soil had built up to over 648 million seeds/ha, and was then within 50% of the initial weed seed population.”
t0“Corn(Zea mays)”
Claim · model-written summary
Corn grain yield fell 39% in year five where atrazine had been discontinued.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- atrazine had been discontinued after 3 yre0
- Outcome
- grain yieldse0
- Direction
- reducede0
- Value
- 39e0
- Qualifier
- fifthe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the fifth and sixth years, grain yields were reduced 39 and 14%, respectively, where atrazine had been discontinued after 3 yr.”
t0“Corn(Zea mays)”
Claim · model-written summary
Corn grain yield fell 14% in year six where atrazine had been discontinued.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- atrazine had been discontinued after 3 yre0
- Outcome
- grain yieldse0
- Direction
- reducede0
- Value
- 14%e0
- Qualifier
- sixthe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the fifth and sixth years, grain yields were reduced 39 and 14%, respectively, where atrazine had been discontinued after 3 yr.”
t0“Corn(Zea mays)”
The same questions in other papers
atrazine · yield · Zea mays (maize)Results differ
34 papers in the same direction as this paper · 205 in the opposite direction
- negative
- positive
- positive
236 papers more in this group
See all 240 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.