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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.

The growing importance of rice globally over the past three decades is evident in its strategic place in many countries’ food security planning policies. Still, its cultivation emits substantial greenhouse gases (GHGs). The Indica and Japonica sub-species of Oryza sativa L. are mainly grown, with Indica holding the largest market share. The awareness, economics, and acceptability of Japonica rice in a food-insecure Indica rice-consuming population were surveyed. The impact of parboiling on Japonica rice was studied and the factors which most impacted stickiness were investigated through sensory and statistical analyses. A comparison of the growing climate and greenhouse gas emissions of Japonica and Indica rice was carried out by reviewing previous studies. Survey results indicated that non-adhesiveness and pleasant aroma were the most preferred properties. Parboiling treatment altered Japonica rice’s physical and chemical properties, introducing gelatinization of starch and reducing adhesiveness while retaining micronutrient concentrations. Regions with high food insecurity and high consumption of Indica rice were found to have suitable climatic conditions for growing Japonica rice. Adopting the higher-yielding, nutritious Japonica rice whose cultivation emits less GHG in these regions could help strengthen food security while reducing GHGs in global rice cultivation.

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.

This study presents an advanced phenology-based approach to map rice fields and their growth stages using Sentinel-1 and Sentinel-2 time-series data combined with k-means clustering and fuzzy deep neural networks (FDNN). The method relies on two main observations: the detection of flooding during transplanting through Sentinel-1 VH backscatter analysis and the identification of growth phase fluctuations using normalized difference vegetation index (NDVI) time series. This approach was applied to Gilan, Iran (14,042 km²), and Niigata, Japan (12,584 km²). Data from January 2019 to December 2020 were processed on the Google Earth engine (GEE) platform, resulting in high-resolution maps at a 10-meter scale. The methodology integrated unsupervised classification and FDNN to effectively identify areas with similar phenological characteristics and detect plant diseases. The resulting maps detailed the extent, intensity, and schedules of rice cultivation, showcasing the seasonal rhythms of planting and harvesting. Validation against high-resolution Google Earth street viewpoints confirmed the accuracy and reliability of the generated maps, demonstrating the robustness and efficiency of the proposed approach. The findings underscore the cost-effectiveness of this method, which accurately delineates rice fields, identifies growth stages, and detects plant diseases over large areas. This capability is crucial for monitoring progress towards self-sufficiency in rice production and for calculating methane emissions from rice paddies. By providing detailed insights into the spatial and temporal dynamics of rice farming, the study offers a valuable tool for agricultural planning and environmental management. The approach’s success in diverse geographic regions highlights its potential for broader application in other rice-producing areas worldwide.

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.

Satellite remote sensing (RS) and machine learning can be combined to develop methods for measuring the impacts of climate change on biomass and agricultural systems. From 2015 to 2023, we applied this approach in a critical earth observation-based evaluation of the Irrigation and Water Resources Management component of the Millennium Challenge Corporation’s Senegal Compact. This project, funded by the United States Agency for International Development (USAID), was implemented in the Senegal River Valley from 2010 to 2015. Utilising these techniques, we successfully mapped rice cultivation areas, deciphered cropping practices, and analysed irrigation systems responses to different climatic conditions. A marked increase in cultivated rice area was found particularly in regions targeted by the project intervention. This is despite prolonged drought conditions which underscores a significant climate adaptation benefit from these irrigation works. We observed a notable dip in rice cultivation area in 2020, possibly due to the COVID-19 pandemic, followed by a recovery to pre-pandemic levels in 2023, likely aided by previously funded USAID’s socio-economic resilience programmes in the region. Economic analysis of increased rice yields in the region translates to approximately US$ 61.2 million in market value since 2015, highlighting the economic returns from the project investment. Both the RS data and ground audits identify issues regarding post-project deterioration of irrigation infrastructure, emphasising the need for long-term maintenance of irrigation infrastructure to support climate adaptation benefits arising from irrigation. With a focus on crop irrigation, our findings stress the critical role of climate adaptation interventions for maintaining agricultural productivity in the face of adverse climate shocks. It further highlights the necessity of continuous investment and maintenance for ensuring climate resilient agrifood systems.

The growing demand for agricultural products, driven by the Green Revolution, has led to a significant increase in food production. However, the demand is surpassing production, making food security a major concern, especially under climatic variation. The Indian agriculture sector is highly vulnerable to extreme rainfall, drought, pests, and diseases in the present climate change scenario. Nonetheless, the key agriculture sub-sectors such as livestock, rice cultivation, and biomass burning also significantly contribute to greenhouse gas (GHG) emissions, a driver of global climate change. Agriculture activities alone account for 10–12% of global GHG emissions. India is an agrarian economy and a hub for global food production, which is met by intensive agricultural inputs leading to the deterioration of natural resources. It further contributes to 14% of the country’s total GHG emissions. Identifying the drivers and best mitigation strategies in the sector is thus crucial for rigorous GHG mitigation. Therefore, this review aims to identify and expound the key drivers of GHG emissions in Indian agriculture and present the best strategies available in the existing literature. This will help the scientific community, policymakers, and stakeholders to evaluate the current agricultural practices and uphold the best approach available. We also discussed the socio-economic, and environmental implications to understand the impacts that may arise from intensive agriculture. Finally, we examined the current national climate policies, areas for further research, and policy amendments to help bridge the knowledge gap among researchers, policymakers, and the public in the national interest toward GHG reduction goals. Graphical Abstract