Abstract
Understanding the methods leading to rice yield increase is vital for sustainable agricultural development. Improving the harvest index (HI) is an important way to increase rice yield. To explore the effects of different water and nitrogen management modes on the rice HI in the black soil region of Northeast China, a field experiment was conducted in 2019 (Y1) and 2020 (Y2). Two irrigation methods, conventional flooding irrigation (FI) and controlled irrigation (CI), were established in the experiment, and four nitrogen application levels (0 kg/ha, 85 kg/ha, 110 kg/ha, and 135 kg/ha) were set during the entire growth period, named N0, N1, N2, and N3. The dry matter weight and the rice yield at the maturity stage were determined, and the HI was then calculated. The results showed that different irrigation modes and nitrogen application levels had significant effects on the rice HI. Under different irrigation modes with the same nitrogen application level during the two years, the comparison regular of HI was consistent. In Y1 and Y2, the HI of FN0 was 3.36% and 5.02% higher than that of CN0 (p < 0.05), and the HI of CN1 was 0.31% and 2.43% higher than that of FN1 (p > 0.05). The HI under CI was significantly higher than that under FI under N2 and N3 (p < 0.05), the HI of CN2 was 4.21% and 4.97% higher than that of FN2, and the HI of FN3 was 13.12% and 20.34% higher than that of CN3. In addition, during the two-year experiment, the HI first increased and then decreased with an increase in the nitrogen application rate under FI and CI. Under the FI treatments, the HI of N1 was the highest, and that of N2 was the highest under the CI treatments. A variance analysis showed that the irrigation pattern and nitrogen application level had significant interactions on the rice HI (p < 0.01), and the appropriate water and N management mode could increase rice the HI by 26.89%. The experimental results showed that the HI of the 110 kg/ha nitrogen application rate under CI was the highest, reaching 0.574 and 0.572, respectively, in two years. This study provides a data reference and theoretical support for realizing water savings, nitrogen reduction, and sustainable agricultural development in the black soil region of Northeast China.
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Claims 11
Claim · model-written summary
Irrigation and nitrogen levels significantly affected rice harvest index.
- Taxon
- Rice
Oryza sativat0 - Treatment
- different irrigation modes and nitrogen application levelse0
- Outcome
- rice HIe0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“different irrigation modes and nitrogen application levels had significant effects on the rice HI”
t0“Rice”
Claim · model-written summary
FN0 harvest index exceeded CN0 by 3.36% in Y1 and 5.02% in Y2.
- Taxon
- RiceOryza sativat0
- Treatment
- FN0e0
- Outcome
- HIe0
- Direction
- highere0
- Value
- 3.36% and 5.02%e0
- Comparator
- CN0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In Y1 and Y2, the HI of FN0 was 3.36% and 5.02% higher than that of CN0 (p < 0.05)”
t0“Rice”
Claim · model-written summary
CN1 harvest index exceeded FN1 by 0.31% and 2.43%, without statistical significance.
- Taxon
- RiceOryza sativat0
- Treatment
- CN1e0
- Outcome
- HIe0
- Direction
- highere0
- Value
- 0.31% and 2.43%e0
- Comparator
- FN1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the HI of CN1 was 0.31% and 2.43% higher than that of FN1 (p > 0.05)”
t0“Rice”
Claim · model-written summary
CN2 harvest index exceeded FN2 by 4.21% and 4.97%.
- Taxon
- RiceOryza sativat0
- Treatment
- CN2e0
- Outcome
- HIe0
- Direction
- highere0
- Value
- 4.21% and 4.97%e0
- Comparator
- FN2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the HI of CN2 was 4.21% and 4.97% higher than that of FN2”
t0“Rice”
Claim · model-written summary
FN3 harvest index exceeded CN3 by 13.12% and 20.34%.
- Taxon
- RiceOryza sativat0
- Treatment
- FN3e0
- Outcome
- HIe0
- Direction
- highere0
- Value
- 13.12% and 20.34%e0
- Comparator
- CN3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the HI of FN3 was 13.12% and 20.34% higher than that of CN3”
t0“Rice”
Claim · model-written summary
Harvest index first rose and then fell as nitrogen application increased.
- Taxon
- RiceOryza sativat0
- Treatment
- nitrogen application ratee0
- Outcome
- HIe0
- Direction
- first increased and then decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the HI first increased and then decreased with an increase in the nitrogen application rate under FI and CI”
t0“Rice”
Claim · model-written summary
N1 had the highest harvest index under FI.
Not reportedMaterial
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under the FI treatments, the HI of N1 was the highest”
t0“Rice”
Claim · model-written summary
N2 had the highest harvest index under CI.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“that of N2 was the highest under the CI treatments”
t0“Rice”
Claim · model-written summary
Irrigation pattern and nitrogen level significantly interacted in their effect on rice harvest index.
- Taxon
- RiceOryza sativat0
- Treatment
- irrigation pattern and nitrogen application levele0
- Outcome
- rice HIe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the irrigation pattern and nitrogen application level had significant interactions on the rice HI (p < 0.01)”
t0“Rice”
Claim · model-written summary
Appropriate water and nitrogen management increased harvest index by 26.89%.
- Taxon
- RiceOryza sativat0
- Treatment
- appropriate water and N management modee0
- Outcome
- HIe0
- Direction
- increasee0
- Value
- 26.89%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“appropriate water and N management mode could increase rice the HI by 26.89%”
t0“Rice”
Claim · model-written summary
Controlled irrigation with 110 kg/ha nitrogen produced the highest harvest index, 0.574 and 0.572 in the two years.
- Taxon
- RiceOryza sativat0
- Treatment
- 110 kg/ha nitrogen application rate under CIe0
- Outcome
- HIe0
- Direction
- higheste0
- Value
- 0.574 and 0.572e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the HI of the 110 kg/ha nitrogen application rate under CI was the highest, reaching 0.574 and 0.572, respectively, in two years”
t0“Rice”
The same questions in other papers
nitrogen · yield · Oryza sativa (rice)Positive and negative results
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