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This paper presents a specific examination of the introduction of grain cultivation and the processes of development in the Japanese Archipelago. In fact, no definitive archaeological evidence has been found that Jomon hunter–gatherers cultivated grain in the Japanese Archipelago; the earliest potential evidence of grain is a stamp mark of rice on the surface of a final late-Jomon, in about 11th century BC, pottery found at the Itaya 3 site in Shimane Prefecture. Current evidence indicates that the first grain cultivation was started by Jomon people who adopted irrigated wet rice cultivation that had arrived from the Korean Peninsula to northern parts of Kyushu, and gradually spread eastward thereafter. This study specifically examines four regions, including northern Kyushu, Kinki, southern Kanto, and northern Tohoku, in order to investigate the processes of grain cultivation initiation and spread. First, the years during which wet rice cultivation started in each region are estimated based on carbon-14 dating of earthenware types used during that period. Secondly, the timing of the spread of wet rice cultivation has been estimated based on carbon-14 dating of earthenware. Subsequently, differences in the periods between the initiation and dissemination of wet rice cultivation were estimated. Results suggest that dissemination took place over approximately 250 years in northern Kyushu, where wet rice cultivation first started. The time required for adoption decreased gradually as the trend moved eastward. It was estimated to have taken approximately 150 years in Kinki and 20–30 years in southern Kanto, taking place at about the same time. A factor, significantly contributing to such differences in timing and development processes among regions, was likely the relationship between the first farmers who introduced wet rice farming and the indigenous hunter–gatherers who lived there.

Rice is food consumed regularly and is vital for the food security of over half the world’s population. Rice production on a global scale is predicted to rise by 58 to 567 million tonnes (Mt) by 2030. Rice contains a significant number of calories and a wide variety of essential vitamins, minerals, and other nutritional values. Its nutrients are superior to those found in maize, wheat, and potatoes. It is also recognised as a great source of vitamin E and B5 as well as carbohydrates, thiamine, calcium, folate, and iron. Phytic acid and phenols are among the phenolic compounds found in rice, alongside sterols, flavonoids, terpenoids, anthocyanins, tocopherols, tocotrienols, and oryzanol. These compounds have been positively linked to antioxidant properties and have been shown to help prevent cardiovascular disease and diabetes. This review examines recent global rice production, selected varieties, consumption, ending stocks, and the composition of rice grains and their nutritional values. This review also includes a new method of paddy storage, drying, and grading of rice. Finally, the environmental impacts concerning rice cultivation are discussed, along with the obstacles that must be overcome and the current policy directions of rice-producing countries.

China’s anthropogenic methane emissions are the largest of any country in the world. A recent study using atmospheric observations suggested that recent policies aimed at reducing emissions of methane due to coal production in China after 2010 had been largely ineffective. Here, based on a longer observational record and an updated modelling approach, we find a statistically significant positive linear trend (0.36 ± 0.04 ( ± 1 σ ) Tg CH 4 yr −2 ) in China’s methane emissions for 2010–2017. This trend was slowing down at a statistically significant rate of -0.1 ± 0.04 Tg CH 4 yr −3 . We find that this decrease in growth rate can in part be attributed to a decline in China’s coal production. However, coal mine methane emissions have not declined as rapidly as production, implying that there may be substantial fugitive emissions from abandoned coal mines that have previously been overlooked. We also find that emissions over rice-growing and aquaculture-farming regions show a positive trend (0.13 ± 0.05 Tg CH 4 yr −2 for 2010–2017) despite reports of shrinking rice paddy areas, implying potentially significant emissions from new aquaculture activities, which are thought to be primarily located on converted rice paddies.

Through the analysis of macro- and micro-plant remains, food residues and the rice-field like features from the mid-Neolithic site of Hanjing in the Huai River region, we propose an early beginning of rice cultivation at Hanjing. The presence of non-shattering rice spikelet bases and the increasing percentages of rice phytoliths confirm the appearance of domesticated rice in the Hanjing archaeobotanical assemblage. However, as indicated by the different prediction rates of rice domestication shown by morphometric of the double-peaked Oryza -type glum cells and fish-scale decorations on the Oryza -type bulliform cells from different cultural phases before 7,000 a BP, rice cultivation was at an early stage of development. Our findings provide new and significant evidence towards the establishment of the Huai River as another important center for early rice cultivation and domestication in prehistoric China.

Introduction. Rice, mainly represented by two species — Oryza sativa (Asian) and Oryza glaberrima (African) — is a strategic cereal for global food security. The species O. sativa is consumed by nearly half of the world’s population. In Africa, and particularly in the Democratic Republic of Congo (DRC), the demand for rice is rapidly increasing due to the combined effects of population growth, urbanization, and changing dietary patterns. However, local production remains insufficient to meet national demand. This article examines the opportunities offered by the rice sector in the DRC as well as the structural constraints that limit its development. Literature. The DRC benefits from diverse agroecological conditions, fertile land, and a growing urban demand, all of which are favorable to rice production. However, several technical and institutional constraints hinder its expansion: weak cultivation practices, limited access to quality seeds, soil degradation, land tenure insecurity, the dollarization of the economy, irrigation and financing deficits, and the poor quality of locally produced rice. Conclusions. Despite considerable potential for rice production, the DRC remains dependent on imports. The sustainable development of the rice sector requires coordinated improvements across all segments of the value chain, investment in local processing, and the implementation of coherent agricultural policies that promote competitiveness and food sovereignty.

The significant increase of surface air temperature in Africa during the recent industrial period has been previously attributed to emissions from rapidly growing urbanization and industrial emissions. This study highlights the rapid growth of rice cultivation as another major influencing factor. We estimate that a 436% (14 million hectares) surge in rice cultivation area during the industrial period (1960-2018) in the sub-Saharan African region is associated with an increase of 603 million tons of agricultural methane emissions, making it the largest source of methane among all sectoral contributors, including energy, industrial processes, waste, land-use change, and forestry. These changes are further associated with an increase in the total surface air temperature anomaly to 1.3 C, with greenhouse gas (GHG) forcing alone accounting for a rise from 0.47 C to 0.92 C throughout the industrial era compared to pre-industrial baseline (1850–1900), as estimated using the Regular Optimal Fingerprinting (ROF) method. Continued rice cultivation expansion to feed Africa’s rapidly growing population holds the potential for further intensifying current and future warming conditions. However, adopting more sustainable rice farming practices can help to reduce emissions and mitigate these effects.

Rice cultivation plays a vital role in the Southeast Asian (SEA) economy, but it poses environmental challenges and contributes a significant amount of greenhouse gas emissions. To address these concerns, sustainable agricultural practices (SAPs) for rice production have been introduced to mitigate the environmental impact of rice production while fostering economic and social sustainability. However, the adoption of these practices remains limited, highlighting the need for a critical review of existing literature to gain deeper insights into the factors influencing farmers’ adoption of these practices in SEA countries. This review analyzed 39 manuscripts to assess the current state of SAPs for rice cultivation in SEA. We found that socio-demographic variables and farm management variables were frequently examined in these studies, with varying levels of significance. Economic and institutional variables were moderately studied and tended to have more significant findings. There is a noticeable research gap regarding behavioral factors, emphasizing the need for further investigation in SEA. Furthermore, the findings underscore the importance of conducting additional research to develop effective monetary and non-monetary incentives and explore methodologies to address the gaps in understanding farmers’ trade-offs and preferences among different SAPs. These efforts are crucial for promoting the widespread adoption of SAPs in rice cultivation.

Rice cultivation significantly contributes to greenhouse gas emissions, particularly carbon dioxide (CO₂), due to plant respiration and soil microbial activity. This study investigates the potential of ferric oxide (FO) supplementation as a mitigation strategy for CO₂ emissions in rice paddies. A controlled pot experiment was conducted to assess the effects of FO application and its interaction with time after planting on CO₂ emissions and rice yield. Results indicate a peak in CO₂ emissions around 40 days after planting, with FO supplementation reducing emissions in a dose-dependent manner. Additionally, the interaction between FO application and plant growth stages significantly influenced emission patterns. FO-treated soils exhibited lower CO₂ fluxes while maintaining rice productivity, suggesting its potential role in modifying soil biochemical processes. These findings provide new insights into CO₂ dynamics in rice cultivation and highlight FO supplementation as a promising approach for mitigating emissions. Further research is warranted to optimize FO application strategies and assess long-term environmental sustainability in diverse rice-growing conditions.

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 m 3 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 cultivation on paddy soil is commonly associated with emissions of methane, a greenhouse gas, but rice varieties may differ in their actual level of emissions. This study analysed methane emissions associated with 22 distinct rice genotypes, using gas chromatography, and identified the cultivar Heijing 5 from northern China as a potential low-methane rice variety. To confirm this and to examine whether Heijing 5 can perform similarly at higher latitudes, Heijing 5 was cultivated in field trials in China (lat. 32° N) and Sweden (lat. 59° N) where (i) methane emissions were measured, (ii) methanogen abundance in the rhizosphere was determined using quantitative PCR, and (iii) the concentrations of nutrients in water and of heavy metals in rice grain and paddy soil were analysed. The results demonstrated that the low-methane rice cultivar Heijing 5 can successfully complete an entire growth period at high-latitude locations such as central Sweden. Massively parallel sequencing of mRNAs identified candidate genes involved in day length and cold acclimatisation. Cultivation of Heijing 5 in central Sweden was also associated with relatively low heavy metal accumulation in rice grains and lowered nutrient losses to neighbouring water bodies.