Efficient water management is crucial for modern rice cultivation, particularly in the context of climate change and limited water resources. To optimize irrigation, this study evaluated the physiological responses of rice to water stress. From January to April 2022, a randomized complete block design (RCBD) was employed to evaluate physiological traits associated with water regulation in rice plants. Key photosynthetic metrics, including stomatal conductance (g_sw), leaf temperature (T_leaf), fluorescence (F_s), electron transport rate (ETR), and photosystem II efficiency (Φ_PSII), as well as stress markers such as malondialdehyde (MDA) content and osmolality, were monitored. Results showed that g_sw shifts preceded visible stress symptoms, making them reliable early indicators of irrigation need. In the second experiment, water-use efficiency, plant stress, and greenhouse gas (GHG) emissions were measured from October 2022 to February 2023 to refine alternative wetting and drying (AWD) methods for better water-use efficiency. Using g_sw thresholds, the modified AWD (mAWD) outperformed conventional AWD (cAWD) in terms of irrigation water productivity (WP_I) and consumptive water footprint (WF_consumption) without inducing stress conditions in rice. WP_I for continuous flooding (CF), cAWD, mAWD was 1.16, 2.72 and 3.92 kg m⁻³, while WF_consumption was 1,079.93, 584.90 and 517.57 m³ t⁻¹, respectively. Additionally, mAWD reduced yield-scaled GHG emissions, enhancing environmental benefits. This study underscores the value of physiological monitoring, especially g_sw, to advance AWD irrigation for sustainable rice production.

Rice serves as a fundamental sustenance for approximately half of the global population, particularly in Asia. Nevertheless, the cultivation of rice demands a substantial water supply, and the challenges associated with water deficits have been exacerbated by irregular rainfall patterns induced by global warming. Consequently, there is a critical need to reassess irrigation techniques to effectively tackle these issues. In this comprehensive review, the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) method was employed to systematically explore literature on irrigation techniques aimed at fostering sustainable water management in rice cultivation systems. The primary components of the framework encompass water consumption and water-related characteristics, soil-related characteristics, and plant-related characteristics, encompassing relevant components and indicators. Two alternative irrigation methods, namely alternate wetting and drying (AWD) and saturated soil irrigation (SSI), have been proposed to enhance water use efficiency (WUE) in rice cultivation compared to traditional continuous flooding (CF). These alternative irrigation methods do not adversely affect rice yield, both quantitatively and qualitatively. Furthermore, these alternative irrigation approaches have the potential to mitigate greenhouse gas (GHG) emissions, particularly methane emissions, in rice production. This review underscores the significance of data on alternate irrigation systems, providing valuable insights for researchers and policymakers in formulating strategies that align at every level for practical implementation. This is crucial as it is relevant to multiple organizations and stakeholders. Moreover, in the face of inclement weather conditions resulting from climate change, the study's findings indicate that research on farmers' adaptation, plant stress, and resilience within the rice cultivation system is still in its nascent stages. This highlights the pressing need for further exploration and advancement in these areas to develop effective strategies for coping with the challenges posed by climate change.

Water management by policy makers is based on multi-perspective information. In the case of water, scarcity causes public health, economic, and ecosystem problems because of the lack of safe water when the demand exceeds its availability. This study identified the influencing components of water scarcity management performance by systematic review methods based on two English full-text databases: Scopus and ScienceDirect from 2012 to 2022. A total of 22 studies were selected from 850 records by using the inclusion criteria and performance evaluation by the scoring rubric method. Moreover, the article quality was assessed using a critical appraisal tool by the Joanna Briggs Institute (JBI) critical appraisal checklist method. The result of this review revealed that the main influencing components of water scarcity management are related to the availability of water quantity and demand. Water availability is associated with the hydrological cycle which has uncertainty due to climate change. While the demand components depend on water use, population, industry and urbanization. Most of the studies in the literature review considered only water balance of water availability and demand. Such an approach is insufficient to achieve water security for sustainable development goals. Additional components including environmental components such as water quality degradation should be considered as these components can reduce the availability of freshwater resources. From an economic point of view, the benefit of water utilization should be prioritized in scarce water management in consideration of fairness in water rights. It is also essential to consider the contribution to socio-economic aspects from stakeholder meetings and participation.

As climate change worsens, irrigation modernization has become critical for better water distribution and maintaining rice production in the face of increasing water constraints. However, there remains a gap in quantification regarding the environmental trade-offs between pump-managed and gravity-based irrigation systems, especially in integrated assessments that relate economic performance, carbon emissions, and water use. This study used an integrated framework of water productivity (WP), consumptive water footprint (WF), carbon footprint, and eco-efficiency to compare gravity-based and pump-managed systems in the Don Chedi Operation and Maintenance Project, Thailand, from 2021 to 2023. The results showed no significant differences in WP and WF between systems. WP averaged 0.39 kg m⁻³ during the wet seasons and 0.54 kg m⁻³ during the dry seasons, while the WF averaged 2517 m³ t⁻¹ and 1854 m³ t⁻¹, respectively. These findings indicate that pump-managed irrigation enhanced operational flexibility and yield stability but did not substantially improve water use efficiency. However, compared with the gravity-based system, the pump-managed system produced much greater carbon emissions, with total carbon footprints ranging from 1.252 to 1.333 tCO₂eq t⁻¹, or five times higher in the irrigation process. Eco-efficiency metrics rose by up to 8.11% despite this environmental burden, indicating enhanced economic resilience amid fluctuating water conditions. These results show a recurring trade-off between low-carbon agricultural development and irrigation modernization. The study therefore emphasizes the importance of integrating renewable energy and low-carbon technologies into pump-based irrigation systems to support climate-resilient and sustainable agricultural transitions.