Abstract
• Coupled PSO and DSSAT to model Lao rice systems under severe data scarcity. • Simulated rice yield and CH 4 , N 2 O, and NH 3 emission in Laos. • Identified a national economic N guidance band of 25–30 kg N ha −1 . • Province-specific N tuning improved profit while maintaining high NUE. Rice production in the Lao People’s Democratic Republic (Lao PDR) is fundamental to national food security, yet its productivity and environmental impacts remain poorly quantified due to limited monitoring and data availability. To address this challenge, we developed a spatially explicit and cost-effective regional rice crop modelling framework by coupling the Decision Support System for Agro-technology Transfer (DSSAT) model with a particle swarm optimization (PSO) algorithm. This hybrid framework was applied to simulate rice growth and associated environmental impacts across Laos from 2012 to 2022. Using available provincial yield statistics for model calibration, we quantified rice yields and greenhouse gas emissions in wet-season rain-fed rice systems. At the province scale, fertilizer response curves show that high fertilizer prices relative to rice prices substantially reduce the economically optimum N application rate. We identified a national guidance range of 25–30 kg N ha −1 with province-specific adjustments, capable of improving farm profitability (70–110%) while sustaining high N use efficiency (NUE) (90–110 kg kg −1 ). Our results highlight the potential for Laos to advance environmentally sustainable (green) rice production. The proposed PSO + DSSAT framework offers a transferable tool for supporting sustainable rice management in regions with limited data coverage.
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The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 5
Claim · model-written summary
The PSO and DSSAT framework simulated rice growth and environmental impacts across Laos from 2012 to 2022.
- Taxon
- rice
Oryza sativae0 - Outcome
- rice growth and associated environmental impactse0
- Value
- 2012 to 2022e0
- Setting
- Laose0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This hybrid framework was applied to simulate rice growth and associated environmental impacts across Laos from 2012 to 2022.”
Claim · model-written summary
High fertilizer prices relative to rice prices reduced the economically optimum nitrogen rate.
- Taxon
- riceOryza sativae0
- Outcome
- economically optimum N application ratee0
- Direction
- reducee0
- Comparator
- rice pricese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high fertilizer prices relative to rice prices substantially reduce the economically optimum N application rate”
Claim · model-written summary
The model identified a national nitrogen guidance range of 25–30 kg N ha −1.
- Taxon
- riceOryza sativat0
- Outcome
- national guidance rangee0
- Value
- 25–30 kg N ha −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We identified a national guidance range of 25–30 kg N ha −1 with province-specific adjustments”
t0“rice”
Claim · model-written summary
Province-specific nitrogen adjustment could improve farm profitability by 70–110%.
- Taxon
- riceOryza sativat0
- Outcome
- farm profitabilitye0
- Direction
- improvinge0
- Value
- 70–110%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“with province-specific adjustments, capable of improving farm profitability (70–110%) while sustaining high N use efficiency (NUE) (90–110 kg kg −1 )”
t0“rice”
Claim · model-written summary
Province-specific nitrogen adjustment could sustain nitrogen use efficiency at 90–110 kg kg −1.
- Taxon
- riceOryza sativat0
- Outcome
- N use efficiency (NUE)e0
- Value
- 90–110 kg kg −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“with province-specific adjustments, capable of improving farm profitability (70–110%) while sustaining high N use efficiency (NUE) (90–110 kg kg −1 )”
t0“rice”