Abstract
Core Ideas Quantified high‐temperature intensity, frequency, and duration as HDH index. High‐temperature episodes between booting and flowering increased significantly. High‐temperature episodes had a significant negative effect on rice yield. Booting and flowering stages of rice are most sensitive to high‐temperature episodes. However, the effect of spatial‐temporal characteristics of high‐temperature episodes on booting and flowering stages in the middle‐season rice cropping region of China were less commonly found in the literature. A data analysis of historical climate and rice yield was conducted to characterize the spatial and temporal variability of high‐temperature episodes between booting and flowering stages and their impact on middle‐season rice grain yield in China. Three high‐temperature indices, including high‐temperature hours (HH), high‐temperature intensity (HI), and high‐temperature degree hours (HDH), were developed to quantify the high‐temperature intensity, frequency, and duration based on maximum temperature records of the last 30 yr from 219 stations in the main middle‐season rice cropping area of China. The HH and HI indices between booting and flowering stages increased significantly in all subregions. Especially in the Central China (CC) subregion, high‐temperature episodes were more severe than those in the East China (EC) subregion and Southwest (SW) subregion. The HDH index, considering the duration and intensity of high‐temperature episodes, was required to describe the correlation between high‐temperature episodes and yield variability. Significant negative ( p < 0.05) impacts of the variability of high‐temperature episodes on the observed grain yield were found in all subregions. Rice yield would decrease by 113.9 kg ha −1 , 19.1 kg ha −1 , and 22.2 kg ha −1 with an HDH increase of 1.0°C·d in the EC, CC, and SW subregions, respectively. High‐temperature episodes were detrimental to middle‐season rice production of China.
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Claims 7
Claim · model-written summary
Heat hours and intensity increased between rice booting and flowering in every subregion.
- Taxon
- Rice
Oryza sativat0 - Organ / stage
- booting and flowering stagese0
- Outcome
- HH and HI indicese0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The HH and HI indices between booting and flowering stages increased significantly in all subregions.”
t0“Rice Yield in China”
Claim · model-written summary
Heat episodes were more severe in Central China than in East and Southwest China.
- Taxon
- RiceOryza sativat0
- Outcome
- high‐temperature episodese0
- Direction
- more severee0
- Comparator
- East China (EC) subregion and Southwest (SW) subregione0
- Setting
- Central Chinae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in the Central China (CC) subregion, high‐temperature episodes were more severe than those in the East China (EC) subregion and Southwest (SW) subregion”
t0“Rice Yield in China”
Claim · model-written summary
The duration and intensity based HDH index was needed to describe the heat–yield correlation.
- Outcome
- correlation between high‐temperature episodes and yield variabilitye0
- Qualifier
- considering the duration and intensitye0
Not reportedComparatorValue
Verbatim
e0“The HDH index, considering the duration and intensity of high‐temperature episodes, was required to describe the correlation between high‐temperature episodes and yield variability.”
Claim · model-written summary
Heat episode variability was negatively associated with observed rice grain yield across all subregions.
- Taxon
- RiceOryza sativat0
- Outcome
- observed grain yielde0
- Direction
- negativee0
- Setting
- all subregionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significant negative ( p < 0.05) impacts of the variability of high‐temperature episodes on the observed grain yield were found in all subregions.”
t0“Rice Yield in China”
Claim · model-written summary
In East China, rice yield decreased 113.9 kg ha −1 for each 1.0°C·d increase in HDH.
- Taxon
- RiceOryza sativae0
- Outcome
- yielde0
- Direction
- decreasee0
- Value
- 113.9 kg ha −1e0
- Qualifier
- HDH increase of 1.0°C·de0
- Setting
- ECe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice yield would decrease by 113.9 kg ha −1 , 19.1 kg ha −1 , and 22.2 kg ha −1 with an HDH increase of 1.0°C·d in the EC, CC, and SW subregions, respectively.”
Claim · model-written summary
In Central China, rice yield decreased 19.1 kg ha −1 for each 1.0°C·d increase in HDH.
- Taxon
- RiceOryza sativae0
- Outcome
- yielde0
- Direction
- decreasee0
- Value
- 19.1 kg ha −1e0
- Qualifier
- HDH increase of 1.0°C·de0
- Setting
- CCe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice yield would decrease by 113.9 kg ha −1 , 19.1 kg ha −1 , and 22.2 kg ha −1 with an HDH increase of 1.0°C·d in the EC, CC, and SW subregions, respectively.”
Claim · model-written summary
In Southwest China, rice yield decreased 22.2 kg ha −1 for each 1.0°C·d increase in HDH.
- Taxon
- RiceOryza sativae0
- Outcome
- yielde0
- Direction
- decreasee0
- Value
- 22.2 kg ha −1e0
- Qualifier
- HDH increase of 1.0°C·de0
- Setting
- SWe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice yield would decrease by 113.9 kg ha −1 , 19.1 kg ha −1 , and 22.2 kg ha −1 with an HDH increase of 1.0°C·d in the EC, CC, and SW subregions, respectively.”