Abstract
The use of controlled-release urea (CRU) has been recommended over that of conventional urea to improve rice grain yield and nitrogen use efficiency. However, the underlying agronomical and physiological mechanisms need to be better understood. In this study, field trials over four site-years, and a big container experiment were carried out to explore CRU effects on rice yield and NUE, with the main aims to identify the key yield components contributing to the superior rice yield with CRU use, and to evaluate differences in dry matter, nitrogen (N) accumulation, translocation and yield formation with different N fertilizer practices. Four N treatments were investigated: control with 0 kg N ha-1 (CK), farmers’ fertilizer practice (FFP) with 150 kg N ha-1 as urea basal application, modified fertilizer practice (MFP) with 150 kg N ha-1 as split urea application (40% at transplanting, 30% at tillering and 30% at the panicle stages), and CRU treatment with 150 kg N ha-1 as CRU basal application. Results showed that the CRU increased rice yields by 10.8% and 5.6% over FFP and MFP, respectively. The N recovery efficiency and N agronomic efficiency for CRU were significantly higher than that obtained from MFP and FFP treatments. The analysis of yield components revealed that the higher grain yields using CRU were accounted for mainly by increased panicle and spikelet numbers per m2, which resulted from higher N uptake. In addition, results from the container experiment with comparable experimental design to field trials illustrated that both post-anthesis dry matter production and translocation were critical for high grain yields using CRU, while the former seemed more important. Relative to MFP and FFP, CRU maintained higher flag leaf SPAD and photosynthetic rate, as well as higher root oxidation activity (ROA) and N uptake during grain filling. Furthermore, CRU increased the activities of key enzymes involved in N assimilation in flag leaves, including GS, GOGAT and NR. CRU effects on such underground and aboveground processes were proposed to contribute to high rice yield.
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Claims 13
Claim · model-written summary
CRU increased rice yield by 10.8% over FFP.
- Taxon
- rice
Oryza sativae0 - Treatment
- CRUe0
- Outcome
- rice yieldse0
- Direction
- increasede0
- Value
- 10.8%e0
- Comparator
- FFPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the CRU increased rice yields by 10.8% and 5.6% over FFP and MFP, respectively.”
Claim · model-written summary
CRU increased rice yield by 5.6% over MFP.
- Taxon
- riceOryza sativae0
- Treatment
- CRUe0
- Outcome
- rice yieldse0
- Direction
- increasede0
- Value
- 5.6%e0
- Comparator
- MFPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the CRU increased rice yields by 10.8% and 5.6% over FFP and MFP, respectively.”
Claim · model-written summary
CRU had significantly higher N recovery efficiency than MFP and FFP.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- N recovery efficiencye0
- Direction
- highere0
- Comparator
- MFP and FFP treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“The N recovery efficiency and N agronomic efficiency for CRU were significantly higher than that obtained from MFP and FFP treatments.”
Claim · model-written summary
CRU had significantly higher N agronomic efficiency than MFP and FFP.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- N agronomic efficiencye0
- Direction
- highere0
- Comparator
- MFP and FFP treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“The N recovery efficiency and N agronomic efficiency for CRU were significantly higher than that obtained from MFP and FFP treatments.”
Claim · model-written summary
Higher CRU grain yield was mainly accounted for by increased panicle number per m2.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- higher grain yieldse0
- Qualifier
- increased paniclee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“the higher grain yields using CRU were accounted for mainly by increased panicle and spikelet numbers per m2, which resulted from higher N uptake.”
Claim · model-written summary
Higher CRU grain yield was mainly accounted for by increased spikelet number per m2.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- higher grain yieldse0
- Qualifier
- spikelet numbers per m2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“the higher grain yields using CRU were accounted for mainly by increased panicle and spikelet numbers per m2, which resulted from higher N uptake.”
Claim · model-written summary
Higher N uptake accounted for increased panicle and spikelet numbers.
- Taxon
- RiceOryza sativat0
- Outcome
- increased panicle and spikelet numbers per m2e0
- Qualifier
- higher N uptakee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“increased panicle and spikelet numbers per m2, which resulted from higher N uptake.”
Claim · model-written summary
Post-anthesis dry matter production was critical for high grain yield under CRU.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- high grain yieldse0
- Qualifier
- post-anthesis dry matter productione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“both post-anthesis dry matter production and translocation were critical for high grain yields using CRU, while the former seemed more important.”
Claim · model-written summary
Post-anthesis dry matter translocation was critical for high grain yield under CRU.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- high grain yieldse0
- Qualifier
- translocatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“both post-anthesis dry matter production and translocation were critical for high grain yields using CRU, while the former seemed more important.”
Claim · model-written summary
Post-anthesis dry matter production appeared more important than translocation.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- high grain yieldse0
- Direction
- more importante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“both post-anthesis dry matter production and translocation were critical for high grain yields using CRU, while the former seemed more important.”
Claim · model-written summary
CRU maintained higher flag leaf SPAD and photosynthetic rate than MFP and FFP during grain filling.
- Taxon
- RiceOryza sativat0
- Organ / stage
- flag leafe0
- Treatment
- CRUe0
- Outcome
- flag leaf SPAD and photosynthetic ratee0
- Direction
- highere0
- Qualifier
- during grain fillinge0
- Comparator
- MFP and FFPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“Relative to MFP and FFP, CRU maintained higher flag leaf SPAD and photosynthetic rate, as well as higher root oxidation activity (ROA) and N uptake during grain filling.”
Claim · model-written summary
CRU maintained higher root oxidation activity and N uptake than MFP and FFP during grain filling.
- Taxon
- RiceOryza sativat0
- Treatment
- CRUe0
- Outcome
- root oxidation activity (ROA) and N uptakee0
- Direction
- highere0
- Qualifier
- during grain fillinge0
- Comparator
- MFP and FFPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“Relative to MFP and FFP, CRU maintained higher flag leaf SPAD and photosynthetic rate, as well as higher root oxidation activity (ROA) and N uptake during grain filling.”
Claim · model-written summary
CRU increased flag leaf GS, GOGAT and NR activities.
- Taxon
- RiceOryza sativat0
- Organ / stage
- flag leavese0
- Treatment
- CRUe0
- Gene
- GS, GOGAT and NRe0
- Outcome
- activities of key enzymes involved in N assimilatione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“CRU increased the activities of key enzymes involved in N assimilation in flag leaves, including GS, GOGAT and NR.”
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