Climate change and declining water resources adversely affect rice production. Conventional continuous flooding in rice cultivation requires high water input, posing challenges under water scarcity and contributing to greenhouse gas (GHG) emissions. Alternate wetting and drying (AWD) is a water‐saving irrigation method that addresses water limitations in flooded cultivation. A Scopus literature search resulted in 1,830 articles, of which 77 were selected for quantitative analysis based on inclusion and exclusion criteria. The critical review revealed that AWD reduces water input, increases water productivity and use efficiency. Physiological adjustments include enhanced indole acetic acid, abscisic acid, and cytokinin regulation, and increased enzymatic activities of sucrose and starch synthases. These changes improve root architecture and gas exchange traits, and facilitate efficient assimilate partitioning to maintain stable grain yield. AWD mitigates GHG emissions, reduces pests and disease incidences. Integration of organic amendments enhances soil health and moisture retention capacity. However, widespread adoption is hindered by weed infestations, sociocultural resistance, and economic risk perceptions. Research gaps include limited integration of weed and nutrient management, uncertain AWD performance under extreme weather events, and yield variations due to agroecological conditions. Addressing these through targeted research, local agricultural policies and farmer‐centric strategies is key to promoting AWD for sustainable rice cultivation.

Rice cultivation is a major contributor to agricultural nitrous oxide (N2O) emissions, a greenhouse gas with a global warming potential approximately 300 times greater than carbon dioxide (CO2) and an atmospheric lifetime of ~121 years. Although water-saving irrigation practices, including Alternate Wetting and Drying (AWD) and Mid-Season Drainage (MD), effectively reduce methane (CH4) emissions by up to 27.6% and decrease irrigation water use by 15–30%, they often intensify soil aeration and stimulate microbial nitrification-denitrification, leading to substantial increases in N2O emissions. Reported increases range from 28.8% to more than 16-fold, with specific studies showing rises from 0.02 to 0.51 kg N2O-N ha−1 under AWD and up to 242% under MD. These trade-offs threaten the long-term sustainability of water-saving rice systems. Iron-based soil amendments (IA) have emerged as a promising mitigation strategy to counteract these elevated N2O emissions. For instance, iron (Fe) powder enhances the activity of Fe-reducing bacteria, such as Geobacter and Anaeromyxobacter, generating Fe2+ and lowering the soil's redox potential, which promotes the complete reduction of N2O to N2. Furthermore, other Fe amendments, including Fe-modified biochar and soluble ferrous iron (Fe2+), help mitigate N2O emissions by immobilizing NH4+, reducing the populations of ammonia-oxidizing bacteria, and supplying surplus electrons that enable denitrifiers to fully reduce N2O to N2. Empirical studies show that Fe-based amendments can reduce N₂O emissions by ~40% (iron-slag silicate fertilizer) and lower nitrification rates from 9.38 to 5.43 μg N g−1 d−1 when applied as Fe-modified biochar. Iron powder also enhances atmospheric N fixation, reducing reliance on synthetic nitrogen fertilizers. Integrating IA with AWD and/or MD, therefore, offers a synergistic pathway to sustain the benefits of water-saving irrigation while minimizing unintended increases in N2O emissions. Field-scale, multi-season studies are still needed to validate long-term impacts and assess residual Fe behavior, but current evidence demonstrates strong potential for these combined strategies to support climate-resilient, low-emission rice production aligned with global mitigation goals.

Agricultural methane (CH₄) emissions remain a critical yet under-addressed component of global climate mitigation, particularly in tropical economies. This study investigates the long- and short-run drivers of CH₄ emissions from Indonesia’s agricultural sector between 1970 and 2022, focusing on three major sources: rice cultivation, enteric fermentation, and manure management. Using a dynamic econometric framework—including Autoregressive Distributed Lag (ARDL), Dynamic Ordinary Least Squares (DOLS), and Newey–West estimators—we quantify source-specific impacts and evaluate structural changes following post-2008 climate policy reforms. Results confirm rice cultivation as the dominant long-run contributor, where a 1% increase in CH₄ from paddy fields corresponds to a 0.72% rise in total agricultural methane emissions. Enteric fermentation and manure management also show significant effects, though to a lesser extent. A post-2008 policy dummy indicates a structural shift in emission dynamics, reflecting Indonesia’s transition toward climate-aligned agriculture through REDD+ and the National Action Plan for GHG Reduction (RAN-GRK). Short-run dynamics reveal corrective adjustments after emission shocks, highlighting system responsiveness to policy and environmental changes. The study underscores both the potential and the limitations of national mitigation efforts in reshaping long-term emission trends. Findings suggest that methane mitigation strategies—such as alternate wetting and drying (AWD) in rice farming and improved feed quality for livestock—can reduce emissions without compromising productivity. This study offers novel empirical insights for policymakers and climate practitioners seeking to integrate food security, sustainability, and low-emission agricultural development in emerging economies.

Arsenic (As) accumulation in rice (Oryza sativa L.) is considered a major environmental and food safety concern, particularly in flooded agroecosystems where reducing conditions mobilize As from soils. Portugal is one of Europe’s rice producers, especially in the Tejo, Almansor, and Sorraia valleys. As such, this study evaluates As pathways across 5000 ha of rice fields in the Tagus, Sorraia, and Almansor alluvial plains by combining soil, water, and plant analyses with a geostatistical approach. The soils exhibited consistently elevated As concentrations (mean of 18.9 mg/kg), exceeding national reference values for agricultural soils (11 mg/kg) and forming a marked east–west gradient with the highest levels in the Tagus alluvium. Geochemical analysis showed that As is strongly correlated with Fe (r = 0.686), indicating an influence of Fe-oxyhydroxides under oxidizing conditions. The irrigation waters showed low As (mean of 2.84 μg/L for surface water and 3.51 μg/L for groundwater) and predominantly low sodicity facies, suggesting that irrigation water is not the main contamination vector. In rice plants, As accumulation follows the characteristic organ hierarchy roots > stems/leaves > grains, with root concentrations reaching up to 518 mg/kg and accumulating progressively in the maturity phase. Arsenic content in harvested rice grains was 266 μg/kg (with a maximum of 413.9 μg/kg), being close to EU maximum limits when considering typical inorganic As proportions, assuming 60 to 90% inorganic fraction. Together, the findings highlight that a combined approach is essential, and identify soil geochemistry (and not irrigation water) as the primary source of As transfer in those agroecosystems, due to the flooded conditions that trigger the reductive dissolution of Fe oxides, releasing As. Additionally, the results also identified the need for targeted monitoring in areas of elevated As content in soils and support future mitigation through As speciation analysis, cultivar selection, improved fertilization strategies, and water-management practices such as Alternate Wetting and Drying (AWD), to ensure the long-term food safety.

Abstract Water scarcity is a growing challenge for sustainable agriculture, particularly in water-intensive crops like rice. This study evaluates the impacts of three irrigation methods; drip irrigation (D), alternate wetting and drying (AWD), and continuous flooding (CF) on rice yield, water productivity, and economic returns over three years. Two irrigation levels (I1: Application of water equal to 25% of the water between the saturation point and field capacity when the soil moisture was near field capacity, I2: Application of water to field capacity when 25% of the available water holding capacity was depleted) were applied. Results revealed that irrigation methods and levels significantly influenced rice yield at the 1% level. The highest average yield (7.95 t/ha) was obtained from CF, followed by AWDI1 (7.60 t/ha) and DI1 (6.39 t/ha). Drip irrigation and AWD reduced water use by 30–57% compared to CF but resulted in yield losses of 2–52%. However, the AWDI1 treatment recorded the highest water productivity and net income (US$2455 ha), outperforming CF and DI1. Economic analyses confirmed the viability of AWD and drip irrigation as sustainable alternatives to CF, balancing water conservation with profitability. These methods are particularly effective in regions with limited water availability, offering a sustainable approach to rice cultivation without significant trade-offs in yield quality. This study also underscores the importance of integrating physical and economic indicators when selecting irrigation strategies to ensure food security and resource sustainability in the face of water scarcity.

Redox-mediated Fe-P coupling modulates phosphorus releasing in paddy soils: Hydrological controls under water-saving irrigation.

High temperature attributed to climate change is a major obstacle to rice production. This study examined how alternate wetting and drying (AWD) irrigation can mitigate the effects of high temperatures on rice production. Three indica rice cultivars-Ye Xiang You You Si (YXYYS), Jing Zhan 1 (JZ1), and Qing Xiang You Yi 19 (QXYY19)-with varying heat susceptibility levels were used to analyse the impact of AWD on spikelet fertility, grain traits, and the biosynthesis of 2-acetyl-1-pyrroline (2-AP) from heading to harvest in rice grown under high temperature. The findings revealed that AWD significantly reduced spikelet fertility in all cultivars, but its effect on spikelet fertility depends on the heat susceptibility level of each cultivar. AWD alleviated the negative effect of high temperature on the biosynthesis of 2-AP and increased 2-AP content in leaves and grains of rice. This study also provided new insights on the effect of starch granules and brown rice grain width on chalkiness and demonstrated that starch granule arrangement and airspaces-not starch granule size-as well as brown rice grain width influenced chalkiness in rice. It also revealed that rice husk affected grain shape. Cooked rice elongation and rice whiteness were significantly increased by AWD, but it reduced the seed germination rate. This study presents a roadmap for the improvement of spikelet fertility in rice grown under high temperature. It also presents a simplified and cost-effective means to further increase the biosynthesis of 2-AP, proffered solutions for the reduction of chalkiness, and proposed methods for the improvement of grain shape by targeting genes, quantitative trait loci (QTLs), and signalling pathways associated with those traits in rice.

Rice is a staple food for about three billion people and is crucial for global food security, but climate change poses serious threats to water resources and crop yields. Alternate Wetting and Drying (AWD) irrigation has emerged as a promising solution, enabling farmers to reduce water use by up to 25 percent compared to traditional irrigation practices. The main purpose of this study was to determine farmers’ perceptions of climate change and the adoption of Alternate Wetting and Drying irrigation technology for rice production in northwest Bangladesh. Specifically, the study assessed farmers’ perceptions of climate change in relation to AWD use in rice production and examined the adoption status of AWD and the factors influencing its adoption among farmers. The study was conducted in Kalma village, Tanore Upazila, in northwest Bangladesh. Data were collected through a questionnaire survey administered to 80 randomly selected farmers. SPSS software was used to analyze farmers’ perceptions of climate change and their adoption of AWD irrigation in rice farming. The findings show that AWD adoption in the study area is satisfactory and largely driven by water scarcity, although 45 percent of adopters lack full knowledge of the technology. AWD adoption improves water-use efficiency, reduces production costs and greenhouse gas emissions, and increases rice yields. The adoption of AWD is significantly influenced by farmers’ education level, household size, farm size, farming experience, access to information, and training. The study concludes that AWD adoption in northwest Bangladesh contributes to improved water efficiency, reduced emissions, and higher rice yields. To maximize the benefits of AWD, adequate farmer training, access to resources, and supportive infrastructure and policy measures are essential.

Southeast Asia is battered by intensifying climate hazards, yet the region continues to feed hundreds of millions through its vast rice bowls. Climate-Smart Agriculture (CSA) is increasingly regarded as the most viable route to sustain production, slash greenhouse-gas emissions, and strengthen farmer resilience in the face of worsening shocks. This systematic review consolidates the strongest field-based evidence currently available across the region. Methane emissions are reduced by approximately 35 % and global warming potential by 29 % when Alternate Wetting and Drying (AWD) is correctly applied, while irrigation water use drops substantially and rice yields remain stable or increase modestly. Greenhouse-gas fluxes are suppressed by roughly 20 % through biochar incorporation, and crop productivity is raised between 10 % and 28 %, with the most pronounced benefits observed on the acidic, low-fertility soils that dominate mainland and insular Southeast Asia. In the Lower Mekong Basin, the System of Rice Intensification (SRI) has been shown to deliver average yield gains of 52 % alongside 70 % higher net economic returns. Despite these robust outcomes, widespread uptake is still constrained by multiple barriers. Training is often inadequate, initial investment costs are perceived as prohibitive, and access to land, credit, extension services, and timely information is distributed unequall-particularly disadvantaging women farmers. Large evidence gaps persist for non-rice agroecosystems and for standardised, comparable indicators of resilience. The review therefore concludes with a clearly sequenced research and policy agenda aimed at shifting CSA from scattered demonstration plots to landscape-scale transformation across Southeast Asia’s diverse farming systems.

ABSTRACT Rice is traditionally grown under continuous flooded (CF) conditions; however, it is a major source of CH4 and N2O emissions. The alternate wetting and drying (AWD) technique can reduce water usage and CH4 emission in rice cultivation, though its impact on grain yield remains uncertain. This study evaluated the AWD effects on grain yield, water use efficiency (WUE), CH4, and N2O emissions in rice cultivation. Three varieties, TT-30, TCS-10, and TTW-31, were cultivated in Taiwan during the 2023 wet season (WS-2023) and the 2024 dry season (DS-2024). The results, based on averages across both seasons and three varieties, indicated that AWD improved WUE by 8.9% but resulted in a 13.4% reduction in grain yield compared with CF. Additionally, AWD reduced CH4 emissions by 53.8% and lowered the global warming potential (GWP) by 21.6%. While AWD increased N2O emissions, these were relatively small compared with CH4 emissions. TT-30 produced the highest yield under AWD conditions. Our findings suggest that AWD reduces CH4 emissions and enhances WUE. Further research is needed to optimize irrigation strategies that conserve water without negatively impacting grain yield. Choosing rice varieties with stronger root systems and more panicles per plant can further enhance the benefits of AWD.

ABSTRACT Dairy wastewater, a nutrient-rich resource, presents a viable strategy to boost agricultural productivity in regions facing severe water scarcity. The comprehensive study at Bangladesh Agricultural University evaluated the effects of conventional irrigation (CI) and water-saving alternate wetting and drying (AWD) practices using varying ratios of dairy wastewater and freshwater on wheat cultivation through a meticulously designed lysimeter experiment. The investigation encompassed six distinct treatments with three replications each, analyzing growth performance, yield components, water productivity, and soil microbiological properties. Results demonstrated that conventional irrigation with pure wastewater (CIW) produced the highest grain yield (4.76 t/ha) and straw yield (5.75 t/ha), along with superior growth parameters, including plant height and spike density. In contrast, alternate wetting and drying with wastewater (AWDW) achieved remarkable water savings of up to 49.78% compared to CIW and recorded the highest water productivity (1.08 kg/m3). Microbiological analysis revealed no Salmonella, and E. coli were detected in post-harvest soil samples under the tested conditions, though significantly higher total viable counts were observed in AWDW treatments, indicating enhanced microbial activity. These findings demonstrate that dairy farm wastewater irrigation significantly improves wheat yields and water use efficiency, offering a sustainable agricultural solution for water-scarce regions like Bangladesh.

Lowland rice cultivation is a major contributor to agricultural greenhouse gas (GHG) emissions. Managing water and fertilizer is important GHG emissions. This paper evaluated GHG emissions of rice production under contrasting water regimes, i.e., continuous flooding (CF) versus alternate wetting and drying (AWD), with six nitrogen fertilizer combinations: no nitrogen (F1), urea 175 kg ha-1 (F2), urea 350 kg ha-1 (F3), urea 262.5 kg ha⁻¹ + manure 3 tons ha-1 (F4), urea 525 kg ha⁻¹ + rice straw 3 tons ha-1 (F5), and urea 175 kg ha⁻¹ + manure 3 tons ha-1 + biochar 0.6 tons ha-1 (F6). The field experiments were conducted at Bogor Regency, West Java, Indonesia, using a randomized complete block design with three replications. Growth, yield components, and GHG emissions were observed in this study throughout the growing season. Results showed AWD reduced CH₄ emissions by 30% but increased N₂O by 43% compared to CF, yielding a net 23% lower global warming potential (GWP). Organic-amended treatments (F6) maintained yields equivalent to conventional fertilization while showing numerically lower GWP. The independent effect of the water regime and the nitrogen fertilizer combinations implies that the best level of biochar and manure combined with AWD has the most promising prospect of maintaining rice yield while reducing GHG emissions.

ABSTRACT Rice ( Oryza sativa L.) is vital for global food security, with China leading in terms of production and consumption. However, current irrigation strategies in China often have low efficiency and poor adaptability to climate variability, partly due to the limited differentiation of water consumption pathways and interannual climate impacts. This study focused on Heilongjiang Province, and used 2023–2024 field observations to calibrate the DSSAT‐CERES‐Rice model for four irrigation regimes: controlled irrigation (CI), shallow‐wet irrigation (SWI), alternate wetting and drying (AWD) and conventional flooding (CK). The model achieved high accuracy for the leaf area index, dry matter accumulation, soil water dynamics and yield. Simulations with climate data from 2005 to 2024 revealed that CI and AWD increased transpiration and reduced evaporation, increasing yields by 5% and 4%, respectively, and evapotranspiration‐based water use efficiency by 5% and 4%, respectively, over those of the CK. SWI effectively reduced evaporation and buffered climate variability but had limited productivity. A fuzzy comprehensive evaluation gave the CI the highest score (3.44) for yield, water use efficiency and climate resilience, identifying it as the most adaptable, promising water‐saving irrigation strategy for Northeast China. These results support sustainable rice production and food security.

Multi-objective water management strengthens synergistic control of nitrogen and phosphorus losses and CH4 emissions in paddies in the Yangtze River Basin.

Water-saving irrigation practices, particularly alternate wetting and drying (AWD), have been widely promoted in paddy rice systems for water conservation and methane emission reduction. However, long-term impacts on soil properties remain inadequately understood. This meta-analysis synthesizes evidence from 62 studies (1998-2024) encompassing 218 comparisons to quantify water-saving irrigation effects on soil organic carbon (SOC), microbial biomass carbon (MBC), and soil structure. Results show water-saving irrigation significantly reduced SOC stocks by 8.7% (95% CI: -11.2% to -6.1%, p<0.001) and MBC by 12.3% (95% CI: -15.8% to -8.7%, p<0.001). Effects were strongly time-dependent, with significant declines emerging only after 5+ years (SOC: -13.4%, MBC: -18.6%). Organic amendments completely offset SOC losses. Microbial communities shifted dramatically, with methanogens declining 68% but methanotrophs increasing 156%. These findings highlight critical trade-offs between water conservation and soil health, emphasizing necessity of adaptive management including organic matter additions and optimized AWD thresholds.

Climate change, coupled with widespread soil arsenic (As) contamination, is expected to decrease rice yields and increase grain As, threatening food security. One promising mitigation strategy is alternate wetting and drying (AWD) irrigation. However, AWD has not previously been tested under potential future climate conditions. Using rhizoboxes to visualize the rhizosphere, we evaluated the efficacy of AWD for limiting porewater and grain As under both current (daily high of 33 °C and 420 ppmv CO2) and severe warming conditions (daily high of 38 °C and 850 ppmv CO2). Compared to continuous flooding, AWD decreased cumulative As exposure 10 cm below the surface by 8.2× under a 33 °C climate and by 15.9× under a 38 °C climate. Grain total As concentrations decreased by 1.5× with AWD under a 33 °C climate and by 1.3× under a 38 °C climate. Porewater cadmium (Cd) concentrations often increased following drainage but never exceeded 1 μg L-1, and grain Cd concentrations were 14.7× to 119.7× lower than grain As concentrations. Both AWD and the 38 °C and 850 ppmv CO2 climate conditions enhanced root growth. Our findings indicate that AWD may still be an effective As mitigation strategy under severe future climate conditions.

Water control systems significantly influence Rice growth and yield, with water-saving strategies, such as Alternate Wetting and Drying (AWD) and controlled irrigation often increasing water productivity and grain yield related to continual flooding, while deep flooding can inhibit growth. The research gap is the lack of specific studies on how modern water management practices like AWD affect the growth and yield of locally important varieties like Binadhan5 and BRRI dhan28. The policy implications suggest that farmers can achieve higher water productivity and water savings by adopting these water-saving methods, leading to more sustainable rice production without compromising yield, particularly in drought-prone or water-scarce areas. A field study was carried out at Bangladesh Agricultural University (BAU) to investigate the impacts of various water control systems on the development and yield of 2 Boro rice varieties Binadhan5 as well as BRRI dhan28. The research was conducted in split-plot design with water management practices in the main plot and rice cultivars in the sub-plot. The water control procedures were as follows: (I1) alternate wetting and drying of the field, indicating the usage of 5 cm irrigation water when the water surface in the pierced PVC pipe decreased 15 cm beneath earth surface, (I2) irrigation after 5 days of saturation, and (I3) continuous flooded condition. The maximum grain yield of rice was obtained from the cultivar Binadhan5 followed by BRRI dhan28. Among the different water management practices, alternate wetting and drying (I1) documented the maximum grain yield of rice followed by irrigation after 5 days of saturation (I2) and continuous flooded condition (I3). The resulting impact has proven that excellent water control measures, as well as the adoption of appropriate varieties, assist to increase yield every droplet of water utilized and can quadruple growers' revenue.

Climate change has intensified heat stress events during critical rice growth stages, threatening global food security. This systematic review and meta-analysis evaluates the efficacy of alternate wetting and drying (AWD) and continuous flooding (CF) irrigation strategies in mitigating heat stress-induced yield losses in rice. A comprehensive search of peer-reviewed literature published between 2010 and 2024 yielded 47 studies meeting inclusion criteria, encompassing 156 independent comparisons across diverse agroecological zones. Meta-analytical results indicate that AWD irrigation reduced yield losses under heat stress by 12.3% compared to continuous flooding, with mean yields of 6.8 t/ha versus 6.1 t/ha respectively. However, the efficacy of AWD varied significantly with stress timing, intensity, and cultivar type. During reproductive stage heat stress (>35°C for 3+ consecutive days), AWD demonstrated superior performance, maintaining 78% of potential yield compared to 68% under continuous flooding. The mechanism underlying this advantage involves enhanced root oxidative capacity, improved canopy temperature regulation through increased transpirational cooling, and maintained photosynthetic efficiency. Economic analysis revealed that AWD implementation provided a 15-18% reduction in water use while maintaining or improving yields under heat stress conditions. This meta-analysis provides robust evidence that strategic irrigation management, particularly AWD, represents a viable adaptation strategy for rice production systems facing increasing heat stress under climate change scenarios.

Extensive practice has demonstrated that the continuous pursuit of high yields in the black soil region of Northeast China resulted in imbalances in soil nutrients and declines in both soil quality and water use efficiency. Alternate wetting and drying (AWD) irrigation offers a promising solution for increasing rice yield and maintaining soil fertility. However, the success of this irrigation method largely depends on its scheduling. This study examined the threshold effects of AWD on rice growth, yield, and soil nutrient availability in the Sanjiang Plain, a representative black soil region in Northeast China. A two-year trial was conducted from 2023 to 2024 at the Qixing National Agricultural Science and Technology Park. “Longjing 31,” a local cultivar, was selected as the experimental material. The lower limit of soil water content under AWD was set as the experimental factor, with three levels: −10 kPa (LA), −20 kPa (MA), and −30 kPa (SA). The local traditional irrigation practice, continuous flooding, served as the control treatment (CK). Indicators of rice growth and soil nutrient content were measured and analyzed at five growth stages: tillering, jointing, heading, milk ripening, and yellow ripening. The results showed that, compared to CK, AWD had minimal impact on rice plant height and tiller number, with no significant differences (p > 0.05). However, AWD affected leaf area index (LAI), shoot dry matter (SDM), yield, and soil nutrient availability. In 2023, control had little effect on rice plant height and tiller number among the different irrigation treatments. The LAI of LA was 11.1% and 22.5% higher than that of MA and SA, respectively, while SDM in LA was 10.5% and 17.2% higher than in MA and SA. Significant differences were found between LA and MA, as well as between LA and SA, whereas no significant differences were observed between MA and SA. The light treatment is beneficial to the growth and development of rice, while the harsh growth environment caused by the moderate and severe treatments is unfavorable to rice growth. The average contents of nitrate nitrogen (NO3−-N), available phosphorus (AP), and available potassium (AK) in LA were 11.4%, 8.4%, and 9.3% higher than in MA, and 16.7%, 11.5%, and 15.0% higher than in SA, respectively. Significant differences were observed between LA and SA. This is because the light treatment facilitates the release of available nutrients in the soil, while the moderate and severe treatments hinder this process. Although panicle number per unit area and grain number per panicle in LA were 7.5% and 2.3% higher than in MA, and 10.8% and 2.2% higher than in SA, these differences were not statistically significant. Seed setting rate and thousand-grain weight showed little variation across irrigation treatments. The yield of LA was 10,233.3 kg hm−2, 9.1% and 14.1% higher than that of MA and SA, respectively, with significant differences observed. Compared with the moderate and severe treatments, the light treatment increases indicators such as the number of panicles per unit area, grains per panicle, thousand-grain weight, and seed setting rate, resulting in significant differences among the treatments. Water use efficiency (WUE) decreased as the control level increased. The WUE of all AWD irrigation treatments was significantly higher than that of the control treatment (CK). Compared with CK, AWD reduces evaporation, percolation, and other water losses, leading to a significant decrease in water consumption. Meanwhile, the yield remains basically unchanged or even slightly increases, thus resulting in a higher WUE than CK. The trends in rice growth, soil nutrient indicators, and WUE in 2024 were generally consistent with those observed in 2023. In 2024, the yield of LA was 9832.7 kg hm−2, 14.9% and 17.3% higher than that of MA and SA, respectively, with significant differences observed. Based on the results, the following conclusions are drawn: (1) AWD irrigation can affect the growth of rice, alter the status of available nutrients in the soil, and thereby cause changes in yield and WUE; (2) LA is the optimal treatment for increasing rice yield, improving the availability of soil available nutrients, and improving WUE; (3) Both MA and SA enhanced WUE; however, these practices negatively impacted rice growth and the concentration of soil available nutrients, leading to a concurrent decline in yield. To increase rice yield and maintain soil fertility, LA, with an irrigation upper limit of 30 mm and a soil water potential threshold of −10 kPa, is recommended for the Sanjiang Plain region.

In response to the increasing urgency of climate change mitigation and the pursuit of carbon neutrality, the role of greenhouse gas (GHG) reduction in the agricultural sector has garnered significant attention. In particular, the cropland sector—responsible for a large share of anthropogenic methane (CH4) and nitrous oxide (N2O) emissions—requires tailored mitigation strategies aligned with distinct crop systems and soil management practices. This study investigates and compares GHG mitigation technologies and their integration into national inventory systems across eight countries: Korea, Japan, China, Vietnam, the Philippines, Indonesia, the United States, and the United Kingdom. The objective is to identify differences in inventory representation levels (based on intergovernmental panel on climate change (IPCC) Tier 1–3 classification), and to provide policy recommendations for improving South Korea’s GHG accounting system. We first categorized mitigation strategies by crop type: paddy fields, where anaerobic conditions drive CH4 emissions, and upland fields, where N2O is primarily released through nitrification and denitrification. Key technologies examined include mid-season drainage, intermittent irrigation, alternate wetting and drying (AWD), biochar, and silicate fertilizers for rice systems; and no-tillage, nitrification inhibitors, cover crops, crop rotation, and biochar for upland systems. Each was assessed based on its mechanistic pathways, empirical mitigation effects, and degree of integration into national reporting through emission factors (EFs), activity data, and simulation modeling. Our results reveal that Japan and the U.S. have established advanced Tier 2–3 inventory structures supported by country-specific EFs and modeling frameworks such as denitrification–decomposition (DNDC) and daily century (DayCent) models. These countries have also institutionalized regular activity data collection and policy linkage. In contrast, Korea has only integrated mid-season drainage into its inventory at Tier 2 level, with most other technologies, especially those applicable to upland systems, remaining at Tier 1 or excluded altogether. Other countries such as China, Vietnam, and the Philippines are undergoing regional trials, while Indonesia remains in a research phase with minimal institutional adoption. These findings suggest that Korea’s current inventory system requires expansion beyond rice-based CH4 mitigation to include upland N2O reduction measures. There is a need to establish crop- and region-specific EFs, long-term field data, and simulation-based estimation methods to support inventory inclusion and policy design. Moreover, stronger alignment is needed between mitigation technologies and incentive-based policies such as direct payment programs, voluntary offset schemes, and environmental stewardship initiatives. This study offers a scientific basis for advancing the national GHG inventory in Korea’s agricultural sector and enhancing the integration of mitigation technologies into climate policy frameworks.