Abstract
Abstract A laboratory study was used to simulate the pattern of diffusion of ammonium and nitrate ions in flooded soil. Ammonium, deep incorporated in a submerged irrigation system, diffused upward from the anaerobic to the aerobic layer where biochemical oxidation nitrified it to NO2 and NO3. These oxidized N species diffused downward from the aerobic layer to the anaerobic layer where most or at least partly, was lost as gaseous end products. Three crops of rice were grown in a glasshouse experiment to estimate N use efficiency under various combinations of irrigation and N management practices. Overall N use efficiency averaged 45%. Under continuous flooding, almost two thirds of the applied fertilizer N (647% use efficiency) was recovered by the rice crop. Under alternate flooding and drying, the response was very poor, with only about one fourth (26% use efficiency) of the applied fertilizer N being recovered by the crop. This demonstrated importance of the proper combination of irrigation and fertilizer management in paddy soils to maximize N utilization.
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Claims 6
Claim · model-written summary
In flooded soil, incorporated ammonium diffused upward and was oxidized to nitrite and nitrate.
- Treatment
- deep incorporated in a submerged irrigation systeme0
- Outcome
- Ammoniume0
- Direction
- diffused upwarde0
Not reportedTaxon
Verbatim
e0“Ammonium, deep incorporated in a submerged irrigation system, diffused upward from the anaerobic to the aerobic layer where biochemical oxidation nitrified it to NO2 and NO3.”
Claim · model-written summary
Oxidized nitrogen species diffused downward and were lost as gas in the anaerobic layer.
Not reportedTaxon
Verbatim
e0“These oxidized N species diffused downward from the aerobic layer to the anaerobic layer where most or at least partly, was lost as gaseous end products.”
Claim · model-written summary
Overall rice nitrogen use efficiency averaged 45%.
Not reportedTaxon
Verbatim
e0“Overall N use efficiency averaged 45%.”
t0“rice”
Claim · model-written summary
Under continuous flooding, rice recovered nearly two thirds of fertilizer nitrogen; the abstract prints 647% use efficiency.
- Taxon
- rice
Oryza sativae0 - Treatment
- continuous floodinge0
- Outcome
- use efficiencye0
- Value
- 647%e0
- Qualifier
- almost two thirds of the applied fertilizer Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under continuous flooding, almost two thirds of the applied fertilizer N (647% use efficiency) was recovered by the rice crop.”
Claim · model-written summary
With alternate flooding and drying, rice recovered about one fourth of fertilizer nitrogen, 26% use efficiency.
- Treatment
- alternate flooding and dryinge0
- Outcome
- use efficiencye0
- Value
- 26%e0
- Qualifier
- only about one fourthe0
Not reportedTaxon
Verbatim
e0“Under alternate flooding and drying, the response was very poor, with only about one fourth (26% use efficiency) of the applied fertilizer N being recovered by the crop.”
t0“rice”
Claim · model-written summary
The authors conclude that irrigation and fertilizer management should be combined properly to maximize nitrogen use in paddy soils.
Not reportedTaxon
Verbatim
e0“proper combination of irrigation and fertilizer management in paddy soils to maximize N utilization.”
t0“rice”