Abstract
Seasonal variations in CH 4 emission rates from rice paddies have been reported to have one or more maxima during the middle and late periods of rice growth. The factor affecting an appearance of CH 4 emission maxima was examined in three types of pot experiments. In the experiment 1, four rice cultivars with difference in length of the period from transplanting to heading were transplanted on the same days. For the experiment 2, a cultivar was transplanted 4 times with interval of two weeks. In these experiments, the heading differed about a month between the earliest and latest treatments, respectively. However, shifting growth stage of rice plants did not shift the CH 4 emission maxima, and the CH 4 emission maxima often matched the maxima of daily mean air temperature. The effect of variation in temperature on CH 4 emission rate was further investigated in the experiment 3 by placing the rice‐planted pots under regulated temperature. Besides the first emission peak of CH 4 attributable to rice straw (RS) carbon, three emission peaks corresponding to the peaks of air temperature were detected for the RS‐applied pots placed outdoors. These three peaks were not observed or much less conspicuous for the RS‐applied pots in a phytotron at 30°C. Temporal decreases in CH 4 emission were detected both for the pots placed in the phytotron and outdoors just after the topdressing of (NH 4 ) 2 SO 4 , which was considered to be a major cause of irregular disagreement between the variations in CH 4 emission rates and in air temperature during the middle period of rice growth.
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Claims 7
Claim · model-written summary
Shifting the growth stage of rice plants did not shift the CH4 emission maxima.
- Taxon
- rice
Oryza sativae0 - Treatment
- shifting growth stagee1
- Outcome
- CH 4 emission maximae1
- Direction
- did not shifte1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal variations in CH 4 emission rates from rice paddies”
e1“shifting growth stage of rice plants did not shift the CH 4 emission maxima”
Claim · model-written summary
The CH4 emission maxima often matched the maxima of daily mean air temperature.
- Taxon
- riceOryza sativae0
- Outcome
- CH 4 emission maximae2
- Direction
- matchede2
- Comparator
- maxima of daily mean air temperaturee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal variations in CH 4 emission rates from rice paddies”
e2“the CH 4 emission maxima often matched the maxima of daily mean air temperature”
Claim · model-written summary
The first CH4 emission peak was attributable to rice straw carbon.
- Taxon
- riceOryza sativae0
- Treatment
- rice straw (RS)e3
- Outcome
- first emission peak of CH 4e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal variations in CH 4 emission rates from rice paddies”
e3“Besides the first emission peak of CH 4 attributable to rice straw (RS) carbon”
Claim · model-written summary
Three CH4 emission peaks corresponding to the peaks of air temperature were detected for RS-applied pots placed outdoors.
- Taxon
- riceOryza sativae0
- Treatment
- RS‐appliede4
- Outcome
- three emission peakse4
- Qualifier
- corresponding to the peaks of air temperaturee4
- Setting
- outdoorse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal variations in CH 4 emission rates from rice paddies”
e4“three emission peaks corresponding to the peaks of air temperature were detected for the RS‐applied pots placed outdoors”
Claim · model-written summary
The three CH4 emission peaks were not observed or much less conspicuous for RS-applied pots in a phytotron at 30°C.
- Taxon
- riceOryza sativae0
- Treatment
- RS‐appliede5
- Outcome
- three peakse5
- Direction
- not observede5
- Setting
- in a phytotron at 30°Ce5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal variations in CH 4 emission rates from rice paddies”
e5“These three peaks were not observed or much less conspicuous for the RS‐applied pots in a phytotron at 30°C”
Claim · model-written summary
Temporal decreases in CH4 emission were detected in phytotron and outdoor pots just after topdressing of (NH4)2SO4.
- Taxon
- riceOryza sativae0
- Treatment
- topdressing of (NH 4 ) 2 SO 4e6
- Outcome
- CH 4 emissione6
- Direction
- decreasese6
- Setting
- phytotron and outdoorse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal variations in CH 4 emission rates from rice paddies”
e6“Temporal decreases in CH 4 emission were detected both for the pots placed in the phytotron and outdoors just after the topdressing of (NH 4 ) 2 SO 4”
Claim · model-written summary
Topdressing of (NH4)2SO4 is considered a major cause of irregular disagreement between CH4 emission rates and air temperature variations.
- Taxon
- riceOryza sativae0
- Treatment
- topdressing of (NH 4 ) 2 SO 4e6
- Outcome
- irregular disagreemente7
- Qualifier
- major causee7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seasonal variations in CH 4 emission rates from rice paddies”
e6“Temporal decreases in CH 4 emission were detected both for the pots placed in the phytotron and outdoors just after the topdressing of (NH 4 ) 2 SO 4”
e7“which was considered to be a major cause of irregular disagreement between the variations in CH 4 emission rates and in air temperature”