Abstract
There are few studies on how nitrogen (N) fertilizer application rates and transplanting densities impact rice yield, root distribution, and N use efficiency in the cold regions of Northeast China. This research involved a two-year field trial utilizing Jinongda 667 as the material. In 2021, three N split-fertilizer applications—T1 (6:3:1), T2 (5:3:2), T3 (4:3:3)—and two transplanting densities—D1 (30 cm × 13.3 cm) and D2 (30 cm × 20 cm)—were compared with the conventional cultivation mode (T0: 175 kg N hm−2, 6:3:1), whereby the N application mode most suitable for increasing density was explored. In 2022, four N application levels—0 (N0), 125 (N1), 150 (N2), and 175 (N3) kg N hm−2—were assessed under the same density treatment to analyze the yield, resource utilization efficiency, and root traits of Jinongda 667. The results indicated that when the transplanting density was 30 cm × 13.3 cm, the application of 5:3:2 fertilizer was more conducive to improving rice yield. Increasing planting density under reduced N input significantly enhanced both rice yield and N use efficiency. In contrast to the conventional cultivation method (D2N3), the treatment of increased planting density (D1N2) under reduced N input led to a 21.2% rise in the number of panicles per square meter and an 8.6% boost in rice yield. Furthermore, increasing planting density under reduced N input significantly enhanced the agronomic efficiency of N fertilizer, the apparent utilization rate, and the N harvest index. It also boosted the SPAD value, photosynthetic rate, and the utilization efficiency of light and N resources in rice. However, it was noted that root enzyme activity decreased. This study demonstrated that increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2, maximized resource utilization efficiency, optimized root absorption capacity, and resulted in higher yields.
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Claims 12
Claim · model-written summary
At 30 cm × 13.3 cm density, the 5:3:2 fertilizer split better improved rice yield.
- Taxon
- rice
Oryza sativae0 - Treatment
- application of 5:3:2 fertilizere0
- Outcome
- rice yielde0
- Direction
- improvinge0
- Qualifier
- transplanting density was 30 cm × 13.3 cme0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when the transplanting density was 30 cm × 13.3 cm, the application of 5:3:2 fertilizer was more conducive to improving rice yield”
Claim · model-written summary
Higher density with reduced nitrogen significantly increased rice yield.
- Taxon
- riceOryza sativae0
- Treatment
- Increasing planting density under reduced N inpute0
- Outcome
- rice yielde0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing planting density under reduced N input significantly enhanced both rice yield and N use efficiency.”
Claim · model-written summary
Higher density with reduced nitrogen significantly increased nitrogen use efficiency.
- Taxon
- RiceOryza sativat0
- Treatment
- Increasing planting density under reduced N inpute0
- Outcome
- N use efficiencye0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing planting density under reduced N input significantly enhanced both rice yield and N use efficiency.”
t0“Rice”
Claim · model-written summary
D1N2 increased panicles per square meter by 21.2% versus D2N3.
- Taxon
- RiceOryza sativat0
- Treatment
- increased planting density (D1N2) under reduced N inpute0
- Outcome
- number of panicles per square metere0
- Direction
- risee0
- Value
- 21.2%e0
- Comparator
- D2N3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In contrast to the conventional cultivation method (D2N3), the treatment of increased planting density (D1N2) under reduced N input led to a 21.2% rise in the number of panicles per square meter”
t0“Rice”
Claim · model-written summary
D1N2 raised rice yield by 8.6% versus D2N3.
- Taxon
- riceOryza sativae0
- Treatment
- increased planting density (D1N2) under reduced N inpute0
- Outcome
- rice yielde0
- Direction
- booste0
- Value
- 8.6%e0
- Comparator
- D2N3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In contrast to the conventional cultivation method (D2N3), the treatment of increased planting density (D1N2) under reduced N input led to a 21.2% rise in the number of panicles per square meter and an 8.6% boost in rice yield.”
Claim · model-written summary
Higher density with reduced nitrogen significantly enhanced fertilizer agronomic efficiency, apparent utilization and nitrogen harvest index.
- Taxon
- RiceOryza sativat0
- Treatment
- increasing planting density under reduced N inpute0
- Outcome
- agronomic efficiency of N fertilizer, the apparent utilization rate, and the N harvest indexe0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing planting density under reduced N input significantly enhanced the agronomic efficiency of N fertilizer, the apparent utilization rate, and the N harvest index.”
t0“Rice”
Claim · model-written summary
The density and nitrogen treatment increased rice SPAD value and photosynthetic rate.
- Taxon
- riceOryza sativae0
- Treatment
- increasing planting density under reduced N inpute1
- Outcome
- SPAD value, photosynthetic ratee0
- Direction
- boostede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It also boosted the SPAD value, photosynthetic rate, and the utilization efficiency of light and N resources in rice.”
e1“increasing planting density under reduced N input”
Claim · model-written summary
The density and nitrogen treatment increased efficiency of light and nitrogen resource use.
- Taxon
- riceOryza sativae0
- Treatment
- increasing planting density under reduced N inpute1
- Outcome
- utilization efficiency of light and N resourcese0
- Direction
- boostede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It also boosted the SPAD value, photosynthetic rate, and the utilization efficiency of light and N resources in rice.”
e1“increasing planting density under reduced N input”
Claim · model-written summary
Root enzyme activity decreased under higher density and lower nitrogen.
- Taxon
- RiceOryza sativat0
- Treatment
- increasing planting density under reduced N inpute1
- Outcome
- root enzyme activitye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, it was noted that root enzyme activity decreased.”
e1“increasing planting density under reduced N input”
t0“Rice”
Claim · model-written summary
Higher density with 5:3:2 nitrogen split at 150 kg hm−2 maximized resource utilization efficiency.
- Taxon
- RiceOryza sativat0
- Treatment
- increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2e0
- Outcome
- resource utilization efficiencye0
- Direction
- maximizede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2, maximized resource utilization efficiency”
t0“Rice”
Claim · model-written summary
Higher density with 5:3:2 nitrogen split at 150 kg hm−2 optimized root absorption capacity.
- Taxon
- RiceOryza sativat0
- Treatment
- increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2e0
- Outcome
- root absorption capacitye0
- Direction
- optimizede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2, maximized resource utilization efficiency, optimized root absorption capacity”
t0“Rice”
Claim · model-written summary
Higher density with 5:3:2 nitrogen split at 150 kg hm−2 gave higher yields.
- Taxon
- RiceOryza sativat0
- Treatment
- increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2e0
- Outcome
- yieldse0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2, maximized resource utilization efficiency, optimized root absorption capacity, and resulted in higher yields.”
t0“Rice”
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