At the heart of the biological argument is a reframing of the soil itself. For most of modern agricultural history, the soil microbiome was treated as passive background. The review positions it instead as a primary determinant of agroecosystem sustainability, with bacteria, fungi, archaea and protozoa driving nutrient cycling, plant growth regulation, disease suppression and resilience to drought and salinity. Through biological nitrogen fixation, phosphorus solubilization and organic matter decomposition, these communities regulate the very nutrients on which rice depends, while also shaping root development, hormonal balance and immune responses. Crucially, the authors stress that microbial abundance alone tells researchers little; the future depends on deciphering microbial function, not merely cataloguing microbial diversity.

One of the most striking mechanisms involves plant growth-promoting rhizobacteria equipped with the enzyme ACC deaminase. When rice plants experience drought, salinity or heavy metal stress, they accumulate ethylene, a stress hormone that in excess stunts root growth and accelerates senescence. ACC deaminase-producing bacteria, including species of Pseudomonas and Bacillus, degrade ACC, the immediate precursor of ethylene, into ammonia and alpha-ketobutyrate. This biochemical intervention keeps roots elongating and taking up water under conditions that would otherwise shut them down. The bacteria also prime antioxidant defences, inducing enzymes such as catalase and superoxide dismutase that neutralize the reactive oxygen species responsible for damaging membranes, proteins and DNA during stress.

The review highlights a decisive shift away from single-strain inoculants, which often perform brilliantly in the laboratory but inconsistently in the field, toward synthetic microbial communities, or SynComs, that combine organisms with complementary metabolic functions. The evidence is compelling. In a greenhouse pot experiment, a SynCom of Azotobacter, Azospirillum and Bradyrhizobium strains derived 51.6 percent of root nitrogen from atmospheric fixation, compared with 25 to 45 percent for individual bacteria. In acidic field conditions, a consortium of aluminium-resistant bacteria raised single-panicle rice yields by 26.36 percent by easing soil acidification and aluminium toxicity. In Vietnam, inoculation with Gluconacetobacter diazotrophicus supported normal growth and yield with just 50 kilograms of nitrogen per hectare, half the conventional rate. Metagenomics now allows researchers to identify the gene markers behind nitrogen fixation, phosphate solubilization and siderophore production, moving the field from descriptive diversity studies toward predictive, function-oriented microbiome engineering.

The biological toolkit extends well beyond fertilization. Microbial biocontrol agents suppress pathogens through antibiosis, nutrient competition, niche exclusion and induced systemic resistance. Disease-suppressive soils rely on specialized metabolites such as 2,4-diacetylphloroglucinol, which disrupts fungal cellular processes; lipopeptides, which compromise pathogen membranes; and hydrocyanic acid, which interferes with respiration. Entomopathogenic fungi like Beauveria bassiana and Metarhizium anisopliae penetrate insect cuticles and kill major rice pests, including the brown planthopper and stem borers, with minimal harm to non-target organisms. Delivery, however, remains the weak link: encapsulation in alginate, chitosan or gum Arabic protects inoculants from desiccation and ultraviolet radiation, and in one rice study, alginate-encapsulated Priestia aryabhattai boosted plant dry mass by 74.9 percent and nitrogen uptake by 86.1 percent compared with free cells.

On the engineering side, the review catalogues a digital transformation that is already reshaping rice paddies. Unmanned aerial vehicles fitted with multispectral and hyperspectral sensors can estimate chlorophyll content, biomass and nitrogen status before deficiencies become visible. In field experiments in Southwest China, UAV remote sensing combined with a random forest model predicted the rice nitrogen nutrition index with R-squared values reaching 0.97, enabling targeted top-dressing recommendations. Normalized Difference Vegetation Index-guided systems direct urea and diammonium phosphate to nutrient-deficient zones, cutting runoff and waste. Digital twin models go further, integrating real-time environmental data with metatranscriptomic information on microbial gene expression, so that irrigation and fertilization decisions account for rhizosphere biology as well as soil moisture.

Water and energy innovations complete the non-microbial picture. Alternate wetting and drying irrigation, in which fields are deliberately allowed to dry between floodings, reduced methane emissions by 47.47 percent in a global meta-analysis spanning 93 percent of world rice production, though nitrous oxide emissions rose by 52.20 percent, and severe drying cut grain yields by 22.6 percent. Mild AWD, by contrast, maintained yields while saving 23.4 percent of water. Solar-powered irrigation systems delivered a higher benefit-cost ratio than diesel pumps in Bangladeshi Boro rice production, while rice husk gasification converts residues that would otherwise be burned into electricity and heat. Biochar emerges as a bridge between the two worlds: its porous structure sequesters carbon, retains nutrients and, critically, acts as a biological scaffold that shelters introduced microbial consortia in the field.

The authors are candid about the bottlenecks. Microbial inoculants still fail unpredictably outdoors because of priority effects, niche exclusion and competition with native communities, and their recruitment patterns shift across plant developmental stages, undermining one-size-fits-all products. Host genotype matters enormously: a formulation tuned to one cultivar’s root exudates may colonize poorly on another, and a line bred for acidic soils may fail in saline paddies. Genome-edited microorganisms promise precision but raise biosafety questions about horizontal gene transfer and face fragmented regulation, with the European Union, the United States and India each applying different oversight frameworks. On the digital side, high equipment costs, weak rural connectivity and limited digital literacy exclude precisely the smallholder farmers who need these tools most; a Malaysian survey found middle- and high-income farmers 20 to 22 percent more willing to pay for IoT technologies than their lower-income peers.

The review’s central message is that integration, not replacement, will define the future of rice. Sensor networks can identify where inoculants are most likely to establish; AI-driven decision-support systems can time applications to coincide with favourable soil moisture and nutrient conditions; biochar and conservation tillage can create habitats that keep engineered communities alive; and CRISPR-assisted breeding can produce rice varieties that actively recruit beneficial microbes through tailored root exudates. Emerging directions include stress-responsive SynComs designed to persist through drought and flooding, methanotrophic bacteria that oxidize methane before it escapes paddies, and circular systems in which straw becomes biochar, biochar carries the microbes, and the microbes feed the next crop. Policy will determine the pace: Vietnam’s One Million Hectares of High-Quality and Low-Emission Rice programme, backed by the International Rice Research Institute, shows how national green-growth strategies can pull these technologies from the laboratory into millions of fields. If the authors are right, the next green revolution will not be written in a single molecule, but in the coordinated choreography of genomes, microbes, satellites and sunlight.

Subject of Research: Integrated microbiome and green technologies for sustainable rice production

Article Title: Integrated Microbiome and Green Technologies for Sustainable Rice Production: Current Advances, Challenges and Future Perspectives

Article References: Aminurrasyid, A. H., Nadarajah, K. K., & Ikmal, A. M. (2026). Integrated Microbiome and Green Technologies for Sustainable Rice Production: Current Advances, Challenges and Future Perspectives. Journal of Agriculture and Food Research, Article 103359. https://doi.org/10.1016/j.jafr.2026.103359

Image Credits: AI Generated

DOI: 10.1016/j.jafr.2026.103359

Keywords: rice, microbiome, SynComs, biofertilizers, precision agriculture, alternate wetting and drying, biochar, CRISPR, methane emissions, solar irrigation, digital agriculture, sustainable farming

The planetary health framework, first articulated in a landmark 2015 Lancet Commission led by Sarah Whitmee and colleagues, describes the health of human civilisation and the state of the natural systems that support it as inextricably linked. Applied to rice, the framework demands that agronomists, water engineers, climatologists, ecologists and disease specialists stop treating the paddy as a purely agricultural system and instead evaluate it as a coupled human–environment system. The authors of the new comment, drawn from institutions including the London School of Hygiene and Tropical Medicine, the World Health Organization, the International Rice Research Institute, Eawag, Deltares, the United Nations University Institute for Water, Environment and Health and several European universities, contend that this integrated lens can reveal win–win interventions that sector-by-sector analysis routinely misses.

The first and most visible cost is water. Irrigated rice is among the most water-intensive crops on the planet, traditionally grown under continuous flooding that keeps the root zone saturated throughout the growing season. Much of the water applied is lost to seepage, percolation and evaporation, placing enormous pressure on surface and groundwater resources in regions where rice dominates cropping systems. As competition for water intensifies and climate change makes supplies less reliable, water scarcity is becoming a binding constraint on rice production in major growing regions, threatening the very food security the crop is meant to guarantee.

The second cost is climatic. Continuously flooded paddies create the oxygen-depleted, or anaerobic, soil conditions in which methanogenic microorganisms thrive, making rice cultivation a substantial source of methane, a greenhouse gas far more potent than carbon dioxide over short time horizons. Reviews of the evidence, including work synthesised by Qian and colleagues in Nature Reviews Earth and Environment, have quantified the scale of these emissions and the agronomic levers that influence them. Water management sits at the heart of the problem: the same flooding that suppresses weeds and stabilises yields is what generates the methane, creating a direct tension between conventional agronomy and climate mitigation.

The third cost is the least appreciated: rice paddies can serve as habitat for the mosquitoes and snails that transmit some of the world’s most important vector-borne diseases. Standing water in irrigated agroecosystems can support Anopheles mosquitoes that transmit malaria, vectors of Japanese encephalitis and other arboviruses, and aquatic snails involved in schistosomiasis transmission. The relationship between rice systems and disease is complex and context-dependent, and a systematic review by Chan and colleagues published in Scientific Reports in 2022 examined how agricultural and environmental changes in rice-growing landscapes influence malaria risk. The historical record shows that this connection was recognised decades ago, with the International Rice Research Institute convening work on vector-borne disease control through rice agroecosystem management as early as 1988, and studies such as Mutero and colleagues in Acta Tropica in 2000 testing how water management in Kenyan irrigation schemes could reduce mosquito breeding.

Crucially, the authors argue, these three problem domains are not independent, and managing them separately can create perverse trade-offs. Alternate wetting and drying, a water-saving technique in which fields are allowed to dry intermittently rather than being kept permanently flooded, has been shown in trials reported by Lampayan and colleagues in Field Crops Research to reduce water use substantially while maintaining yields, and it also suppresses methane emissions because intermittent aeration of the soil inhibits methanogens. But the same drying cycles change the hydrology of the paddies in ways that could alter mosquito breeding habitat and snail populations, and the direction of that effect on disease transmission is not uniform across settings. Similarly, intensification strategies that raise yields may increase water demand or pesticide loads, while climate adaptation measures designed to protect rice from heat and drought may reshape the disease ecology of the landscape. Only an integrated assessment can reveal where interventions produce co-benefits and where they shift burdens from one domain to another.

The stakes of getting this wrong are rising. Expansion of rice cultivation is a central pillar of food policy across sub-Saharan Africa, where the Coalition for African Rice Development has promoted ambitious production targets as a route to import substitution and food sovereignty. Research by Jiang and colleagues has documented how rice expansion in Africa changes land and water use, while other recent work has examined the environmental consequences of intensification. If new rice schemes are designed purely for agronomic output, the comment’s authors warn, they risk locking in water stress, methane emissions and vector-borne disease burdens for decades. Conversely, if planetary health principles are embedded at the design stage, the same expansion could be steered toward practices that conserve water, limit emissions and reduce disease risk from the outset.

The technical toolkit for such integrated management already exists in pieces. Beyond alternate wetting and drying, options include site-specific water regimes tailored to local vector ecology, cultivar and fertiliser choices that influence methane fluxes, drainage and edge management that reduce breeding sites for mosquitoes and snails, and landscape-level planning that weighs rice against alternative crops in water-stressed basins. Studies such as those by Echeverría-Progulakis and colleagues in Agriculture, Ecosystems and Environment, Cuong and colleagues in Environmental Challenges, and González and colleagues in the Journal of Environmental Management have begun to quantify the environmental footprints and trade-offs of different rice management options, while work on arsenic and other contaminants in paddy systems, reviewed by Abedi and Mojiri in Plants, adds further dimensions of soil and water quality to the picture. Adaptation strategies for climate change impacts on rice physiology and agronomy, set out by Wassmann and colleagues in Advances in Agronomy, complete a portfolio that is rich in components but poor in integration.

What is missing, the authors argue, is the connective tissue: institutional arrangements, assessment methods and funding structures that allow agricultural ministries, water authorities, climate negotiators and health agencies to evaluate rice interventions on a common scoreboard. Planetary health provides precisely that common frame, treating human health outcomes, ecosystem integrity and resource sustainability as jointly optimisable objectives rather than competing claims. The comment calls for rice-growing practices to be identified and promoted on the basis of their performance across all these domains at once, which would require cross-sectoral evidence generation, from hydrological monitoring and greenhouse gas measurement to entomological surveillance and epidemiological studies, embedded within agricultural research and development programmes rather than bolted on afterwards.

The message lands at a moment when the pressures on the global rice system are unusually acute. The Food and Agriculture Organization’s Food Outlook report of November 2025 underscores the centrality of rice to world food markets, while climate volatility, water scarcity and the persistent burden of vector-borne disease in rice-growing regions all press in on the same landscapes. The authors, who note that the views expressed are their own and do not necessarily represent those of their affiliated institutions, including the World Health Organization, frame their argument not as a rejection of rice but as a defence of it: the crop’s future depends on managing its full footprint. If the planetary health approach they advocate is adopted, the world’s most important staple could be produced in ways that feed a growing population while easing, rather than deepening, the pressures on water, climate and health. The alternative, they suggest, is a system in which each sector continues to solve its own piece of the puzzle while quietly worsening everyone else’s.

Subject of Research: Integrated management of water, climate and health impacts of rice production using a planetary health framework

Article Title: A planetary health approach is needed to manage the wider impacts of rice production

Article References: Braun, L., Boisson, S., Boelee, E., Chivenge, P., Connor, M., Drakeley, C., Drew, G., Gordon, B., Irish, S. R., Lines, J., Mabhaudhi, T., Müller, M. F., Pinsach Boada, J., Arbat Pujolras, G., Said-Pullicino, D., Tharreau, D., & Cumming, O. (2026). A planetary health approach is needed to manage the wider impacts of rice production. Nature Water. https://doi.org/10.1038/s44221-026-00722-w

Image Credits: AI Generated

DOI: 10.1038/s44221-026-00722-w

Keywords: rice production, planetary health, water scarcity, methane emissions, vector-borne disease, malaria, alternate wetting and drying, food security, irrigation, climate change mitigation, schistosomiasis, sustainable agriculture

The research, published in Environmental Monitoring and Assessment, was carried out by a team of Vietnamese and Japanese scientists led by Ngo Duy Dong of Hiroshima University, working with colleagues at the Vietnam National University of Agriculture, Phenikaa University, the University of Da Nang, and Hiroshima University. Rather than examining a single growing season, the team tracked a paddy field across three consecutive rice cropping seasons, comparing plots managed with alternate wetting and drying against plots kept under continuous flooding. This multi-season design matters, because soil chemistry does not respond to irrigation changes overnight; many of the most important processes unfold over months and years as microbial communities and elemental cycles adjust.

Alternate wetting and drying is deceptively simple in concept. Instead of maintaining a permanent layer of floodwater, farmers allow the field to dry periodically until the water table drops to a defined threshold below the soil surface, and then re-flood it. Each drying episode introduces oxygen into a soil that is normally starved of it. That pulse of oxygen suppresses the strictly anaerobic archaea that generate methane, and it also triggers a cascade of chemical reactions involving iron, manganese, nitrogen, and sulfur. The practice has been promoted for years as a water-saving technique, but questions have lingered about its side effects: does it deplete soil nitrogen, does it change the availability of toxic elements such as arsenic and cadmium, and does the benefit for methane persist over multiple seasons?

The new study addressed these questions with a combination of field observation and controlled laboratory incubations. The researchers measured soil chemical properties, the potential of the soil to produce methane, the rate at which organic nitrogen was mineralized into plant-available ammonium, and the concentrations of a broad suite of elements, from macronutrients to potentially toxic metals. To synthesize this large dataset, they applied principal component analysis, a statistical technique that condenses many correlated measurements into a small number of axes, allowing the overall biogeochemical fingerprint of each water treatment to emerge clearly.

The headline result concerns methane. When soil from the alternate wetting and drying treatment was incubated anaerobically in the laboratory for seven weeks, it produced far less methane than soil from continuously flooded plots. By the end of the incubation period, the difference was stark: 36.2 milligrams of carbon per kilogram of soil under alternate wetting and drying, compared with 96.5 milligrams under continuous flooding, a reduction of roughly 62 percent. This confirms that the effect of intermittent aeration is not merely a transient suppression of methane flux during the drying episodes themselves. The soil retains a diminished methane production potential even when subsequently returned to waterlogged, oxygen-free conditions, suggesting that repeated drying cycles fundamentally alter the microbial and chemical conditions that methanogens depend upon.

Nitrogen dynamics told a more nuanced story. Under alternate wetting and drying, the soil’s total nitrogen content declined to 1.08 grams per kilogram, compared with 1.32 grams per kilogram under continuous flooding. Ammonium accumulation during the incubation was also lower under the drying treatment, at 38.3 milligrams of nitrogen per kilogram of soil versus 62.5 milligrams under continuous flooding. These figures point to accelerated nitrogen transformation under alternating oxygen conditions. Each re-wetting of a dried soil typically triggers a burst of microbial activity, and the alternating presence and absence of oxygen promotes both mineralization and nitrification-denitrification pathways that can move nitrogen out of the organic pool and, in some cases, out of the soil entirely as gaseous losses. For farmers, this is a caution: the water-saving, methane-reducing practice may carry a hidden cost in nitrogen, potentially requiring adjusted fertilizer management to maintain yields.

One of the most interesting findings concerns iron and manganese, the so-called redox-sensitive elements. Concentrations of both were markedly higher in soils under alternate wetting and drying than under continuous flooding. This makes chemical sense. When a flooded soil dries, dissolved reduced iron and manganese oxidize and precipitate as oxides and hydroxides on soil particle surfaces. When the field is re-flooded, these oxides partially re-dissolve, but the repeated cycling changes where these elements reside and in what forms. Iron oxides are important players in paddy soil chemistry because they can adsorb phosphate, arsenic, and other solutes, and because microbes that reduce iron compete with methanogens for substrate. Higher iron and manganese availability under the drying regime may therefore be one of the mechanisms suppressing methane, as iron-reducing bacteria consume the organic matter and hydrogen that would otherwise fuel methane production.

Crucially for food safety, the study found that most macroelements and potentially toxic elements did not differ remarkably between the two water regimes. This addresses a persistent worry in the rice research community. Continuous flooding keeps arsenic in its more mobile, reduced form, and draining fields is sometimes proposed as a way to limit arsenic uptake by rice, but drying can increase cadmium mobility instead. The Vietnamese results suggest that, at least in this soil and over three seasons, alternate wetting and drying did not substantially enhance the accumulation of potentially toxic elements, a finding that supports its applicability as an environmentally sustainable practice rather than a trade-off that simply swaps one contamination risk for another.

The principal component analysis reinforced the picture of a soil fundamentally reorganized by its water history. Rather than scattered differences in individual measurements, the analysis revealed distinct, coherent shifts in the overall biogeochemical characteristics of soils under the two treatments. Soil pH was also significantly higher under alternate wetting and drying, at 6.22 compared with 5.68 under continuous flooding, a shift of more than half a pH unit that can influence nutrient availability, microbial community composition, and the solubility of metals. Periodic aeration tends to consume acidity through oxidation reactions and to alter the balance of alkalinity-generating reduction processes, and a modest pH increase of this kind is generally favorable for rice, since strongly acidic conditions can limit phosphorus availability and increase aluminum toxicity.

Taken together, the study offers a rare multi-season, whole-soil assessment of a practice that is rapidly being scaled up across Southeast Asia. Vietnam is one of the world’s largest rice exporters, and its delta regions face the twin pressures of water scarcity and greenhouse gas reduction targets, making alternate wetting and drying an attractive policy tool. The new evidence strengthens the case that the technique delivers its promised climate benefit, cutting methane production potential by more than half in incubation assays, without accumulating toxic metals in the soil. At the same time, the observed decline in total nitrogen and reduced ammonium accumulation is a signal that farmers adopting the practice will need to monitor nitrogen carefully, adjusting application rates and timing to avoid yield penalties. As climate-smart agriculture moves from pilot plots to millions of hectares, studies of this kind, which track the full elemental consequences of changing one variable as fundamental as water, will be essential for ensuring that the cure for methane does not create new problems in the paddies of the future.

Subject of Research: Effects of alternate wetting and drying irrigation on methane production, nitrogen transformation, and soil elemental dynamics in Vietnamese rice paddies

Article Title: Alternate wetting and drying in Vietnam affects methane production, nitrogen transformation, and soil elemental dynamics across three consecutive rice cropping seasons

Article References: Dong, N. D., Viet, T. D., Hoang, V. D., Dung, L. T., Tam, L. D., Son, T. N., Xuan, T. D., & Toan, N.-S. (2026). Alternate wetting and drying in Vietnam affects methane production, nitrogen transformation, and soil elemental dynamics across three consecutive rice cropping seasons. Environmental Monitoring and Assessment, 198(10), Article 1129. https://doi.org/10.1007/s10661-026-15965-z

Image Credits: AI Generated

DOI: 10.1007/s10661-026-15965-z

Keywords: alternate wetting and drying, rice paddies, methane, soil biogeochemistry, nitrogen mineralization, iron, manganese, soil pH, Vietnam, greenhouse gas mitigation, sustainable agriculture, water management

The review, conducted by researchers at the Bangladesh Rice Research Institute and collaborators, followed the PRISMA 2020 reporting standard and the Synthesis Without Meta-analysis guideline, screening 240 records from five databases down to a final evidence base spanning ten rice-producing countries. The authors deliberately avoided a formal statistical meta-analysis because the underlying trials differed too widely in design, agro-ecology, and reporting quality, opting instead for a structured, semi-quantitative synthesis with explicit confidence ratings for each technology.

The headline numbers are striking. Site-specific nutrient management, including the Nutrient Expert decision-support tool developed by IFDC and CIMMYT, improved rice yields by 6 to 18 percent and nitrogen use efficiency by 20 to 117 percent over typical farmer practice across 143 on-farm trials. In Nepal’s Terai region, a four-year multi-site trial recorded yield gains exceeding 2 tonnes per hectare, roughly doubling farm profitability, while applications across India’s Indo-Gangetic Plains cut the global warming potential of rice by about 2.5 percent and of wheat by 12 to 20 percent.

Integrated nutrient management, which blends organic inputs such as farmyard manure, compost, and green manures with balanced inorganic fertilization, emerged as the strongest long-term foundation for soil health. Across trials in Bangladesh, India, China, the Philippines, and Vietnam, it raised grain yields by 8 to 28 percent and soil organic carbon by 14 to 60 percent over periods of five to twenty years. In Bangladesh, where paddy organic matter averages below 1.5 percent against a target of 2.5 percent for optimal harvests, the most effective strategy combined 2 to 3 tonnes per hectare of poultry manure with 50 to 70 percent of the recommended inorganic fertilizer rate.

On the nitrogen side, controlled-release urea, whose polymer coatings synchronize nitrogen release with crop demand, curbed ammonia volatilization losses by 23 to 62 percent and cut runoff nitrogen losses by 8 to 58 percent. In double-rice systems it reduced annual methane emissions by roughly 19.7 percent and nitrous oxide by 35.2 percent, trimming global warming potential by around 21 percent. Nano-enabled formulations promise nitrogen use efficiency gains of 18 to 30 percent, but the authors caution that field-scale safety and ecotoxicology data remain insufficient for policy recommendations.

Water management delivered some of the most compelling climate results. Alternate wetting and drying irrigation, which lets fields dry to 15 centimeters below the surface between floodings using a simple PVC tube costing one to three dollars, reduced global warming potential by 20 to 36 percent, mainly through lower methane emissions, with generally no yield penalty. A landmark three-year multi-site experiment across Vietnam, Indonesia, Thailand, and the Philippines confirmed GWP reductions of 22 to 36 percent, with yields actually rising by 12 percent at the Thai site. National assessments for the Philippines suggest nationwide adoption could avoid roughly 5.6 megatonnes of carbon dioxide equivalent per year.

The review is careful, however, not to oversell AWD. The same intermittent aeration that suppresses methanogenic archaea can stimulate coupled nitrification and denitrification, raising nitrous oxide, a gas with far higher per-molecule warming power. The net climate benefit therefore depends on the severity of drying, soil texture, and especially how nitrogen is applied. Mild ‘safe’ AWD paired with deep-placed or controlled-release nitrogen tends to preserve the methane savings, while aggressive drying under high broadcast nitrogen can erode them.

That insight points to what the authors identify as the most powerful combination in the entire evidence base: urea deep placement plus alternate wetting and drying. Placing large urea briquettes 7 to 10 centimeters into the anaerobic soil zone keeps nitrogen in its plant-available ammonium form, blocking the volatilization and denitrification pathways that can strip away 30 to 50 percent of broadcast fertilizer. In Bangladesh, deep placement alone raised yields by 10 to 21 percent while saving 25 to 33 percent of nitrogen and cutting GWP by 9 to 21 percent. At a Bangladesh Rice Research Institute farm in Satkhira, the combined approach lifted yields by about 28 percent and nitrogen recovery by 167 percent over broadcast urea, without the additional nitrous oxide emissions often feared under aerobic conditions.

Not every technology earns an unqualified endorsement. Biochar, which can reduce methane emissions by 10 to 43 percent, rests on the weakest and most geographically concentrated evidence, dominated by Chinese trials. Controlled-release fertilizers remain too costly for most South Asian smallholders without targeted subsidies. The evidence base itself skews heavily toward Bangladesh, India, and China, leaving countries such as Pakistan, Myanmar, Cambodia, and Malaysia largely unrepresented, and most organic amendment trials run only three to five years, too short to capture full soil carbon trajectories.

The policy implications are nonetheless concrete. For Bangladesh, the authors recommend immediate scale-up of AWD and deep placement, both already validated and certifiable under the Verra VM0006 carbon methodology, alongside continued digital extension through the Nutrient Expert platform. India is advised to adopt national site-specific nutrient management mandates for irrigated rice in the Indo-Gangetic Plains, where groundwater depletion and residue burning create co-benefit opportunities. The central message is that no single technology optimizes all four sustainability outcomes at once; the largest gains come from locally tailored combinations, with each recommendation’s confidence level traveling with it into the field.

Subject of Research: Smart soil fertility management practices for sustainable rice production in South and Southeast Asia

Article Title: Smart soil fertility management for improving rice yield, nitrogen use efficiency, and greenhouse gas mitigation across South and Southeast Asia

Article References: Islam, S. M. M., Islam, M. N., Naher, U. A., Rahman, F., Hossain, A. T. M. S., Milu, M. K. H., Islam, A., Jahan, A., Khan, M. H., Gaihre, Y. K., & Islam, M. R. (2026). Smart soil fertility management for improving rice yield, nitrogen use efficiency, and greenhouse gas mitigation across South and Southeast Asia. Discover Soil, 3(1), Article 164. https://doi.org/10.1007/s44378-026-00316-8

Image Credits: AI Generated

DOI: 10.1007/s44378-026-00316-8

Keywords: rice, soil fertility, nitrogen use efficiency, greenhouse gas emissions, alternate wetting and drying, urea deep placement, site-specific nutrient management, integrated nutrient management, controlled-release fertilizer, soil organic carbon, methane, climate-smart agriculture