Abstract
Field experiments of nitrogen (N) treatment at five different application rates (0, 75, 150, 225, and 300 kg ha−1) were conducted under pot-seedling mechanical transplanting (PMT) in 2018 and 2019. Two high-quality and high-yielding hybrids of indica rice, Huiliangyou 898 and Y Liangyou 900, were used in this study. The N nutrition index (NNI) and accumulated N deficit (Nand), used to assess the N nutrition status in real-time, were calculated for the indica cultivars under PMT with a critical nitrogen concentration (Nc) dilution model based on shoot dry matter (DM) during the whole rice growth stage. The relationships between NNI and Nand with relative yield (RY) were determined, and accurate N application schemes were developed for hybrids indica rice under PMT. The results indicated that high application rate of N-fertilizer significantly increased the concentrations of shoot DM and N in aboveground organs during the observed stages in the two cultivars for two years (P<0.05). The Nc dilution model of hybrid indica cultivars was Nc=4.02DM−0.42 (R2=0.97) combining the two cultivars under PMT. Root-mean-square error and normalized root-mean-square error of the curve verification were 0.23 and 10.61%, respectively. The NNI and Nand ranged from 0.58 to 1.31 and 109 to –55 kg ha−1, respectively, in the two cultivars for all N treatments. NNI showed a linear relationship with Nand during the entire growth stage (0.53<R2<0.99, P<0.01). In addition, NNI showed a linear-plateau relationship with RY (0.73<R2<0.92, P<0.01) throughout the observed stages. These results suggest that the models can accurately diagnose the N-nutrition status and support effective N-fertilizer management in real-time for hybrid indica rice under PMT.
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Claims 10
Claim · model-written summary
Higher N fertilizer rates significantly increased shoot dry matter.
- Taxon
- hybrid indica rice
Oryza sativa Indica Groupe1 - Organ / stage
- aboveground organse0
- Treatment
- high application rate of N-fertilizere0
- Outcome
- shoot DMe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high application rate of N-fertilizer significantly increased the concentrations of shoot DM and N in aboveground organs during the observed stages in the two cultivars for two years (P<0.05)”
e1“hybrid indica rice”
Claim · model-written summary
Higher N fertilizer rates significantly increased aboveground N concentration.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Treatment
- high application rate of N-fertilizere0
- Outcome
- N in aboveground organse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high application rate of N-fertilizer significantly increased the concentrations of shoot DM and N in aboveground organs during the observed stages in the two cultivars for two years (P<0.05)”
e1“hybrid indica rice”
Claim · model-written summary
The hybrid indica critical N dilution model was Nc=4.02DM−0.42 with R2=0.97.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Outcome
- Nc dilution modele0
- Value
- R2=0.97e0
- Qualifier
- Nc=4.02DM−0.42e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Nc dilution model of hybrid indica cultivars was Nc=4.02DM−0.42 (R2=0.97) combining the two cultivars under PMT”
e1“hybrid indica rice”
Claim · model-written summary
Curve verification root-mean-square error was 0.23.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Outcome
- Root-mean-square errore0
- Value
- 0.23e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root-mean-square error and normalized root-mean-square error of the curve verification were 0.23 and 10.61%, respectively”
e1“hybrid indica rice”
Claim · model-written summary
Curve verification normalized root-mean-square error was 10.61%.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Outcome
- normalized root-mean-square errore0
- Value
- 10.61%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root-mean-square error and normalized root-mean-square error of the curve verification were 0.23 and 10.61%, respectively”
e1“hybrid indica rice”
Claim · model-written summary
NNI ranged from 0.58 to 1.31.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Outcome
- NNIe0
- Value
- 0.58 to 1.31e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The NNI and Nand ranged from 0.58 to 1.31 and 109 to –55 kg ha−1, respectively”
e1“hybrid indica rice”
Claim · model-written summary
Nand ranged from 109 to –55 kg ha−1.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Outcome
- Nande0
- Value
- 109 to –55 kg ha−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The NNI and Nand ranged from 0.58 to 1.31 and 109 to –55 kg ha−1, respectively”
e1“hybrid indica rice”
Claim · model-written summary
NNI had a linear relationship with Nand across growth stages.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Outcome
- NNIe0
- Value
- 0.53<R2<0.99e0
- Comparator
- Nande0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NNI showed a linear relationship with Nand during the entire growth stage (0.53<R2<0.99, P<0.01)”
e1“hybrid indica rice”
Claim · model-written summary
NNI had a linear-plateau relationship with relative yield.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe1
- Outcome
- RYe0
- Value
- 0.73<R2<0.92e0
- Comparator
- NNIe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NNI showed a linear-plateau relationship with RY (0.73<R2<0.92, P<0.01)”
e1“hybrid indica rice”
Claim · model-written summary
The authors conclude the models can diagnose N status and support real-time N fertilizer management.
- Taxon
- hybrid indica riceOryza sativa Indica Groupe0
- Outcome
- N-nutrition statuse0
- Qualifier
- in real-timee0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the models can accurately diagnose the N-nutrition status and support effective N-fertilizer management in real-time for hybrid indica rice under PMT”
The same questions in other papers
nitrogen · growth · Oryza sativa (rice)Positive and negative results
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