Abstract
Abstract Off-target paraquat movement to rice has become a major problem in recent years for rice producers in the midsouthern United States. Nitrogen (N) fertilizer is applied to rice in greater quantity and frequency than all other nutrients to optimize rice yield. Two separate field studies were conducted from 2015 to 2018 in Stoneville, MS, to assess whether starter N fertilizer can aid rice recovery from exposure to a sub-lethal concentration of paraquat and to evaluate rice response to different N fertilizer management strategies following exposure to a sub-lethal concentration of paraquat. In both studies, paraquat treatments consisted of paraquat at 0 and 84 g ai ha –1 applied to rice in the two- to three-leaf (EPOST) growth stage. In the starter fertilizer study, N fertilizer at 24 kg ha –1 as ammonium sulfate (AMS) was applied to rice at spiking- to one-leaf (VEPOST), two- to three-leaf (EPOST), or three- to four-leaf (MPOST) growth stages before and after paraquat treatment. In the N fertilizer timing study, N fertilizer at 168 kg N ha –1 was applied in a single four-leaf to one-tiller (LPOST) application or two-, three-, and two four-way split applications. Despite starter N fertilizer applications, paraquat injured rice ≥41%, reduced height 57%, reduced dry weight prior to flooding 77%, delayed maturity 10 d, reduced dry weight at maturity 33%, and reduced rough rice yield 35% in the starter fertilizer study. Similarly, in the N fertilizer timing study, paraquat injured rice ≥45%, reduced height 14%, delayed maturity 10 d, reduced dry weight at maturity 44%, and reduced rough rice yield 50% for all N fertilizer management strategies. Both studies indicate that severe complications in growth and development can occur from rice exposure to a sub-lethal concentration of paraquat. In both studies, manipulation of N fertilizer management did not facilitate rice recovery from early-season exposure to paraquat.
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Claims 12
Claim · model-written summary
In the starter fertilizer study, paraquat injured rice by at least 41%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥41%”
Claim · model-written summary
In the starter study, paraquat reduced rice height by 57%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥41%, reduced height 57%”
Claim · model-written summary
In the starter study, paraquat reduced dry weight before flooding by 77%.
- Taxon
- rice
Oryza sativae0 - Treatment
- paraquate0
- Outcome
- dry weight prior to floodinge0
- Direction
- reducede0
- Value
- 77%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥41%, reduced height 57%, reduced dry weight prior to flooding 77%”
Claim · model-written summary
In the starter study, paraquat delayed rice maturity by 10 days.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥41%, reduced height 57%, reduced dry weight prior to flooding 77%, delayed maturity 10 d”
Claim · model-written summary
In the starter study, paraquat reduced mature dry weight by 33%.
- Taxon
- riceOryza sativae0
- Treatment
- paraquate0
- Outcome
- dry weight at maturitye0
- Direction
- reducede0
- Value
- 33%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥41%, reduced height 57%, reduced dry weight prior to flooding 77%, delayed maturity 10 d, reduced dry weight at maturity 33%”
Claim · model-written summary
In the starter study, paraquat reduced rough rice yield by 35%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥41%, reduced height 57%, reduced dry weight prior to flooding 77%, delayed maturity 10 d, reduced dry weight at maturity 33%, and reduced rough rice yield 35%”
Claim · model-written summary
In the fertilizer timing study, paraquat injured rice by at least 45%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥45%”
Claim · model-written summary
In the timing study, paraquat reduced rice height by 14%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥45%, reduced height 14%”
Claim · model-written summary
In the timing study, paraquat delayed maturity by 10 days.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥45%, reduced height 14%, delayed maturity 10 d”
Claim · model-written summary
In the timing study, paraquat reduced dry weight at maturity by 44%.
- Taxon
- riceOryza sativae0
- Treatment
- paraquate0
- Outcome
- dry weight at maturitye0
- Direction
- reducede0
- Value
- 44%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥45%, reduced height 14%, delayed maturity 10 d, reduced dry weight at maturity 44%”
Claim · model-written summary
In the timing study, paraquat reduced rough rice yield by 50%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“paraquat injured rice ≥45%, reduced height 14%, delayed maturity 10 d, reduced dry weight at maturity 44%, and reduced rough rice yield 50%”
Claim · model-written summary
Nitrogen management changes did not facilitate recovery from early paraquat exposure.
- Taxon
- riceOryza sativae0
- Treatment
- manipulation of N fertilizer managemente0
- Outcome
- rice recoverye0
- Direction
- did not facilitatee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“manipulation of N fertilizer management did not facilitate rice recovery from early-season exposure to paraquat”
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