Abstract
Direct seeding is a labor-saving rice cultivation method, but poor establishment is a major obstacle to the widespread use of this practice. This study examined the suppressive effect of ammonium sulfate, a nitrogen fertilizer, on seedling establishment in submerged soil. Establishment was impaired even at 20ºC by the application of sulfate salts, including ammonium sulfate and potassium sulfate, but not by ammonium chloride. Impairment by ammonium sulfate did not occur in autoclaved soil. In addition, the redox potential in the soil near the seeds decreased rapidly to levels that allowed sulfide ion generation, even at 20ºC. The sulfur concentration in the soil near the seeds decreased with the decline in redox potential, suggesting that sulfide ions were transformed from soluble sulfate ions into insoluble iron sulfide through binding with ferrous ions near the seeds. These results imply that sulfate ions may be transformed into sulfide ions by bacteria only around the seeds if sufficient sulfate ions are present in the soil, thereby impairing the establishment of seeds sown directly in submerged soil, even under cool springtime conditions and in paddy fields that do not dry out prior to submergence.
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Claims 7
Claim · model-written summary
Ammonium sulfate impaired rice seedling establishment even at 20ºC.
- Taxon
- Rice
Oryza sativat0 - Treatment
- ammonium sulfatee0
- Outcome
- Establishmente0
- Direction
- impairede0
- Qualifier
- even at 20ºCe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Establishment was impaired even at 20ºC by the application of sulfate salts, including ammonium sulfate and potassium sulfate, but not by ammonium chloride.”
t0“Rice Seedlings”
Claim · model-written summary
Potassium sulfate impaired rice seedling establishment even at 20ºC.
- Taxon
- RiceOryza sativat0
- Treatment
- potassium sulfatee0
- Outcome
- Establishmente0
- Direction
- impairede0
- Qualifier
- even at 20ºCe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Establishment was impaired even at 20ºC by the application of sulfate salts, including ammonium sulfate and potassium sulfate, but not by ammonium chloride.”
t0“Rice Seedlings”
Claim · model-written summary
Ammonium chloride did not impair rice seedling establishment.
- Taxon
- RiceOryza sativat0
- Treatment
- ammonium chloridee0
- Outcome
- Establishmente0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Establishment was impaired even at 20ºC by the application of sulfate salts, including ammonium sulfate and potassium sulfate, but not by ammonium chloride.”
t0“Rice Seedlings”
Claim · model-written summary
Ammonium sulfate did not impair rice establishment in autoclaved soil.
- Taxon
- RiceOryza sativat0
- Treatment
- ammonium sulfatee0
- Outcome
- Impairmente0
- Direction
- did not occure0
- Setting
- autoclaved soile0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Impairment by ammonium sulfate did not occur in autoclaved soil.”
t0“Rice Seedlings”
Claim · model-written summary
Redox potential near rice seeds rapidly declined to levels permitting sulfide generation, even at 20ºC.
- Taxon
- RiceOryza sativat0
- Outcome
- redox potential in the soil near the seedse0
- Direction
- decreasede0
- Qualifier
- even at 20ºCe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the redox potential in the soil near the seeds decreased rapidly to levels that allowed sulfide ion generation, even at 20ºC”
t0“Rice Seedlings”
Claim · model-written summary
Sulfur concentration near rice seeds fell as redox potential declined.
- Taxon
- RiceOryza sativat0
- Outcome
- sulfur concentration in the soil near the seedse0
- Direction
- decreasede0
- Setting
- soil near the seedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The sulfur concentration in the soil near the seeds decreased with the decline in redox potential”
t0“Rice Seedlings”
Claim · model-written summary
The authors infer that bacteria convert sulfate to sulfide around rice seeds and impair establishment under submerged conditions.
- Taxon
- RiceOryza sativat0
- Outcome
- establishment of seedse0
- Qualifier
- if sufficient sulfate ions are present in the soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sulfate ions may be transformed into sulfide ions by bacteria only around the seeds if sufficient sulfate ions are present in the soil, thereby impairing the establishment of seeds sown directly in submerged soil”
t0“Rice Seedlings”
The same questions in other papers
potassium sulfate · growth · Oryza sativa (rice)Positive and negative results
3 in the opposite direction
- positive
- positive
- positive
ammonium chloride · growth · Oryza sativa (rice)Positive and negative results
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See all 5 papers →ammonium sulfate · growth · Oryza sativa (rice)Positive and negative results
3 papers in the same direction as this paper · 7 in the opposite direction
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See all 11 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.