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Because of the importance of the Central Valley of California, USA, to shorebirds along the Pacific Flyway, conservation investments have been made in the area's agricultural fields and managed wetlands. Increasingly, landowner incentive programs are being used to deliver shorebird habitat, presenting opportunities to answer remaining questions about which implementation strategies and field management practices are most effective at attracting birds. To provide management guidance for these investments, we collected and analyzed 5 years of data (2014–2018) on shorebird abundance in flooded rice fields enrolled in a dynamic habitat incentive program. The program incentivized flooding in fallow and post‐harvest rice fields in seasons when habitat is relatively sparse, specifically the early fall and late spring. Across nearly 9,000 field observations over 5 years, we explored the relationship between abundance and density (birds/ha) of shorebirds and vegetation cover, soil clay, landscape‐level flooding, and local flood timing, duration, and depth. We observed more shorebirds in fields that were approximately 50% flooded, had water depths of 5–10 cm, and had minimal rice straw or stubble cover, with strong or very strong evidence for each of these relationships. We found that the timing of habitat provisioning was important, with moderate evidence that earlier fall flooding and strong evidence that the duration of fall flooding was associated with higher shorebird density. We observed lower shorebird densities in locations with ample flooded rice habitat in surrounding areas, potentially because shorebirds spread out across the landscape. We found very strong evidence that flooding consistency, either at a site that was continually flooded over many months or a site that had been flooded in previous years, was associated with higher shorebird density. Soil clay content was associated with decreased observed shorebird density, potentially through its influence on the ability of shorebirds to forage for invertebrate prey. These results suggest best practices for shorebird habitat creation in agricultural landscapes, providing important information for conservation and population recovery. [ABSTRACT FROM AUTHOR]

The yellow stem borer (YSB), Scirpophaga incertulas (Walker), is a major insect pest that significantly damages rice crop. This study investigates methods to predict YSB populations in rice fields, aiming to develop an early warning system. Traditionally, rice farmers rely on light traps to monitor YSB presence. However, this study goes beyond this approach by combining light‐trap data with weather information (temperature, humidity, rainfall) and utilizing powerful artificial intelligence (AI) techniques to forecast future YSB populations. Two AI methods, multilayer perceptron (MLP) and long short‐term memory (LSTM), were employed to estimate YSB populations and assess their performance. The results revealed that the LSTM model outperformed the MLP model based on statistical metrics like RMSE, MAE, and R2 values. Utilizing LSTM model with historical data, stakeholders in the Eastern Coastal Plains and Hills agro‐climatic zone of India can gain a significant advantage in predicting YSB populations well in advance. This early warning system can alert stakeholders of potential YSB outbreaks, allowing them to take timely management actions and protect their rice crops from substantial yield losses. [ABSTRACT FROM AUTHOR]

Changes in hydrological processes in watersheds are triggered by various factors, including land use land cover changes (LULCC) emerging from human activities. Hence, it is crucial to elucidate the interaction among hydrological processes to improve sustainable water management plans. The current study explored the effects of LULCC on hydrological processes in the Gala Lake catchment over a 30‐year temporal period. In this context, to evaluate LULCC, land cover maps were obtained using the supervised classification method with Landsat images (5 TM, 7 ETM+, 8 OLI) of 1993, 2008, and 2023. Hydrological processes were assessed using the Soil and Water Assessment Tool (SWAT), a commonly applied eco‐hydrological model. The model was utilized to evaluate the potential effect of LULCC on processes like surface runoff, infiltration, evapotranspiration, and erosion. Between 1993 and 2023, significant LULCC have been observed in the study area. There has been a decrease of 4.3%, 1%, 1.6%, and 5.3% in agricultural lands, forested lands, inland marshes, and pasture lands, respectively, while artificial surfaces, rice fields, and water bodies have seen an increase of 7%, 3.4%, and 1.9%, respectively. The potential effects of these changes were observed as a decrease in the runoff, a decrease in permeability, and an increase in processes such as evapotranspiration and erosion throughout the basin and sub‐basin. In general, LULCC significantly affect the hydrological status of the catchment. Therefore, establishing different conservation and utilization strategies that consider land use dynamics to maintain the resilience of ecosystems in the basins is vital in the sustainable management of water resources. [ABSTRACT FROM AUTHOR]

Peruvian watergrass (Luziola peruviana J.F. Gmel.) is a perennial weed often found in paddy fields in the southern region of Brazil. Its chemical control is performed mainly by herbicides such as glyphosate in burndown, whose efficacy depends on soil moisture. Under excess‐water soil conditions, glyphosate efficacy is reduced, probably due to reduced translocation and the involvement of photoassimilates partition. Furthermore, little is known about the stress tolerance of these plants subjected to water deficit. Based on that, we performed experiments to verify the effect of soil moisture on the biochemical parameters of Peruvian watergrass and glyphosate translocation to the stolon and roots. Total soluble sugars, sucrose, starch, and glyphosate concentrations in leaves, culms, roots, and glyphosate partitioning were quantified. The malondialdehyde content and the lipid peroxidation increased with the drainage. Under drainage conditions, superoxide production was higher in roots than leaves, while peroxide production was lower in roots than leaves. The electrolyte leakage increased with the drainage and glyphosate application. The total soluble sugar content varied in each organ with a significant increase in the culm 14 days after application in the draining treatment. Sucrose varied considerably and reached its maximum concentration at 21 days after herbicide application. The starch accumulation in the culm was 7 days after applying the highest glyphosate dose. The presence of glyphosate in the roots subjected to soil drainage indicates the movement of this herbicide. In conclusion, soil drainage profoundly impacts Peruvian watergrass physiology, increasing the photoassimilates and glyphosate translocation to the stolon and root. This explains why glyphosate efficacy is higher under drainage conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Barnyardgrass (Weed Science Society of America recommended) or Barnyard grass (Britannica recommended) (Echinochloa crus‐galli (L.) P. Beauv.) is one of the most problematic and dominant weeds in world agricultural systems, especially in paddy fields, where tillering and grain yield can be reduced by 50–70% because of its competitive pressure. The frequent use of chemical herbicides to control E. crus‐galli has led to the evolution of herbicide resistance. Developing bioherbicides using pathogenic fungi to control E. crus‐galli could be an alternative option. RESULTS: In a previous study we showed that a strain of Bipolaris yamadae (HXDC‐1‐2) was promising in controlling gramineous weeds. Here we present a study that evaluated this fungus as a mycoherbicide against E. crus‐galli in greenhouse and paddy fields, characterized mycelium growth and conidial production, and examined the infection development. The median effective dose (ED50) and 90% effective dose (ED90) values of microcapsulated B. yamadae strain HXDC‐1‐2 on E. crus‐galli in the greenhouse were 7.17 × 102 and 9.35 × 103 conidia mL−1, respectively. Conidial germination, mycelial growth, and attachment formation occurred on E. crus‐galli leaves within 1 to 6 h. The hyphae directly invaded cells and stomata, primarily from the appressorium on the epidermis, and necrotic lesions were observed on the leaf surface within 20 to 24 h. Applied to E. crus‐galli plants at 1 × 105 conidia mL−1, the fungus reduced the weed's fresh weight of 75%. CONCLUSION: B. yamadae strain HXDC‐1‐2 has the potential to be developed as a bioherbicide against E. crus‐galli plants, especially in rice fields. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) have started to play an important role in pest control, and novel miRNA‐based transgenic insect‐resistant plants are now emerging. However, an environmental risk assessment of these novel transgenic plants expressing insect miRNAs must be undertaken before promoting their application. Here, transgenic miR‐14 rice, which has high resistance to the rice stem borer Chilo suppressalis, was used as an example for evaluation in this study. Taking the tier 1 risk assessment method in Bacillus thuringiensis (Bt) crops as a reference, the effects of the direct exposure of a non‐target parasitoid, Cotesia chilonis, to a high concentration of miRNA were evaluated. The results showed that direct feeding with miR‐14 at high concentration had no significant effects on the biological parameters of Co. chilonis, whereas when miR‐14 was injected into Ch. suppressalis‐parasitized larvae, the development duration of Co. chilonis was significantly affected. In combination with the real conditions of the rice paddy field, it could be inferred that transgenic miR‐14 rice has no significant negative effects on the important non‐target parasitoid, Co. chilonis. These results will provide a foundation for the establishment of a new safety evaluation system for novel RNAi‐based transgenic plants. [ABSTRACT FROM AUTHOR]

SUMMARY: Oocystaenium elegans Gonzalves & Mehra (Oocystaceae, Trebouxiophyceae) was collected from a paddy field in Japan. Its life history was reexamined based on detailed observations of cultured material, and an emended description is given. This species is a large spindle‐shaped green alga that grows in puddles and paddy fields and has been reported in India, Nepal and Cuba. Reproduction occurs asexually via autospore formation and sexually via oogamy. Although this oogamy is considered to involve fertilization by globular egg cells and antherozoids, the results of the present study revealed that the egg cells (female cells) remained spindle‐shaped and became globular zygotes after fertilization. The place on the egg cells where the antherozoid attached swelled to become a receptive papilla, after which the antherozoid invaded. Phylogenetic analysis based on nuclear 18S small subunit ribosomal RNA gene sequences showed that O. elegans is included in the family Oocystaceae. [ABSTRACT FROM AUTHOR]

Methanogenic and methanotrophic microbes together determine the net methane flux from rice fields. Despite much research on them as separate communities, there has been little study of combined community patterns, and how these vary between the rhizoplane (root surface), rhizosphere (soil surrounding the root) and bulk soil around rice plants, especially at larger spatial scale. We collected samples from 32 geographically scattered rice fields in east central China, amplicon targeting the mcrA gene for methanogenesis and pmoA gene for methanotrophy by using high‐throughput sequencing. Distinct communities of both methanogens and methanotrophs occurred in each of the three compartments, and predominantly positive links were found between methanogens and methanotrophs in all compartments indicating cross‐feeding or consortia relationships. Methanogens were acting as the network hub in the bulk soil, and methanotrophs in rhizoplane. Network complexity and stability was greater in the rhizosphere than rhizoplane and bulk soil, with no network hubs detected, suggesting the strongest effect of homeostatic influence by plant occurred in the rhizosphere. The proportion of determinism (homogeneous selection) and distance–decay relation (DDR) in rhizoplane was consistently lower than that in the rhizosphere for both communities, indicating weaker phylogenetic clustering in rice root surface. Our results have provided a better understanding of CH4 oxidation and emission in rice paddy fields and future agriculture management could take into consideration of the subtle variation among different soil compartments and interactions within methanogenic and methanotrophic communities. [ABSTRACT FROM AUTHOR]

The Indonesian governments developed the Upsus Pajale policy to achieve a goal and solve the problem of food self‐sufficiency. Rice, corn, and soybean were the main commodities in the plan of Upsus Pajale Policy implementation. UPSUS Pajale improve rice, corn, and soybean production for food self‐sufficiency. This study examined UPSUS Pajale policy implementation at the province, district, subdistrict, and farmer levels. This study examined rice growing in Banyuasin's tidal lowlands, Ogan Komering Ilir's swamplands, and East Ogan Komering Ulu's irrigated rice fields. The research method used a combination model of quantitative and qualitative (mixed method). Sampling data used purposive sampling. NVivo 12 software examined provincial, district, subdistrict, farmer interviews, and group discussions. Results affected typology management constraints differently. Production input costs were the most common issue. This study found that policy was differently implemented at various levels. It would be impacted to the success of the policy. [ABSTRACT FROM AUTHOR]

The private sector contributes the majority of China's GDP, with family firms responsible for most of the contribution. Prior studies find that firms' family control is influenced by certain cultural norms, such as family ties. This study explores the underlying historical and agricultural roots of these cultural norms that influence modern businesses. Combining a set of high‐quality, nationally representative Chinese firm and household surveys with prefectural data, we first show the positive impact of rice farming on family control of local firms. We establish robust causal inferences by exploring the impact of historical agricultural legacies and discussing alternative measures, spatial autocorrelations, omitted variables, instrumental variables and self‐selection. More importantly, our results demonstrate that the rice cultivation practice enhances the local people's preferences for strong family ties. Instead of claiming a direct role of these cultural traits as in the existing literature, we recast them as cultural mediators and persistent channels through which historical rice farming can shape contemporary corporate structure. [ABSTRACT FROM AUTHOR]

ABSTRACT Rice stripe mosaic virus (RSMV) is an emerging pathogen which significantly reduces rice yields in the southern region of China. It is transmitted by the leafhopper Recilia dorsalis, which overwinters in rice fields. Our field investigations revealed that RSMV infection causes delayed rice heading, resulting in a large number of green diseased plants remaining in winter rice fields. This creates a favorable environment for leafhoppers and viruses to overwinter, potentially contributing to the rapid spread and epidemic of the disease. Next, we explored the mechanism by which RSMV manipulates the developmental processes of the rice plant. A rice heading‐related E3 ubiquitin ligase, Heading date Associated Factor 1 (HAF1), was found to be hijacked by the RSMV‐encoded P6. The impairment of HAF1 function affects the ubiquitination and degradation of downstream proteins, HEADING DATE 1 and EARLY FLOWERING3, leading to a delay in rice heading. Our results provide new insights into the development regulation‐based molecular interactions between virus and plant, and highlights the importance of understanding virus‐vector‐plant tripartite interactions for effective disease management strategies. [ABSTRACT FROM AUTHOR]

Weed control is one of the major challenges in rice cultivation, and the use of agrochemicals for this crop is severely restricted under the new European agricultural policy. Therefore, new effective non‐chemical weed control techniques are the key to sustain European rice production. We investigated four non‐chemical weed management strategies in the Ebro Delta in north‐eastern Spain, two in dry‐seeded rice fields and two in water‐seeded rice fields. In addition, two controls per sowing condition were included: a positive control consisting of chemical herbicides treatment and a negative control consisting of no weeding and no seeding. Mechanical weeding using a rotary harrow placed in front of the seeder was the best weeding technique for dry seeding, while 'stale seed bed' and transplanting was the best performing technique for wet seeding. Both techniques were as effective as the chemical weeding control, reducing the density of weeds and the supplementary manual weeding time needed for those weed species more abundant in Ebro Delta rice fields (i.e., Echinochloa oryzoides, Echinochloa crus‐galli, Bolboschoenus maritimus and Heteranthera reniformis). Thus, non‐chemical weeding alternatives have been proven effective for both, transplanting and dry seeding field management strategies. [ABSTRACT FROM AUTHOR]

Compound plant extracts (CPE) are beneficial for aquatic animals on growth performance and antioxidant capacity. A 56‐day experiment was conducted to investigate its positive effect on rice field eel. The fish were fed a commercial diet and supplementing CPE (mainly containing eucommia polysaccharides, reducing sugar) at 0, 0.8, 1.6, 2.4, and 3.2 g/kg. Results showed that dietary CPE significantly increased weight gain and specific growth rate (p < 0.05). Liver lipid content in 1.6 and 3.2 g/kg groups was significantly lower than in 0.8 and 2.4 g/kg groups (p < 0.05). Muscle lipid content in 0.8, 2.4, and 3.2 g/kg CPE groups was significantly lower than in control (p < 0.05). Meanwhile, intestinal digestive enzymatic activities in the 3.2 g/kg CPE group were the highest in comparison to all other groups (p < 0.05). Dietary CPE enhanced the antioxidant activities of serum and intestine (p < 0.05). Compared with the control, intestinal fold thickness in CPE groups was significantly increased (p < 0.05). Furthermore, dietary CPE reduced the degree of liver steatosis and the number of lipid droplet vacuoles. This study indicated that dietary CPE was beneficial to growth performance, antioxidant capacity, liver, and intestinal histology. Supplementation with 1.6–3.2 g/kg CPE is optimal for this eel species. [ABSTRACT FROM AUTHOR]

Biodiversity in tropical regions is facing threats from agricultural expansion and intensification. Therefore, a promising future for local ecosystem conservation depends not only on traditional protected areas but also on well‐managed agricultural landscapes. In this study, we compared the ecological traits of bird species in paddy fields outside of protected areas and natural forests within the protected areas of Xishuangbanna, southern China. There were 148 species in total, of which 98 were in forests and 55 in paddy fields. The abundance of birds in paddy fields was 176 per kilometer, which was much higher than the 60 per kilometer in forests. There were 26 law‐protected species observed, half of which were found in each habitat. The main functional groups living in nature reserves are invertivores and frugivores, whereas paddy fields provide habitats for aquatic predator and granivore bird species. Our results indicate that paddy fields act as a refuge for wetland and grassland bird species when natural wetlands disappear, highlighting the urgent need to focus more on wetland protection and eco‐friendly agricultural schemes at the landscape scale in future conservation policies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Crop recognition is the basis of intelligent agricultural machine operations. Visual perception methods have achieved high recognition accuracy. However, the reliability of such methods is difficult to guarantee because of the complex environment of paddy fields. Tactile sensing methods are not affected by background or environmental interference, and have high reliability. However, in an ideal environment, the recognition accuracy is not as high as that of the visual method. RESULTS: To balance the accuracy and reliability of rice plant recognition, a combined visual–tactile method was proposed in this study. A rice plant recognition device was developed with a poly(vinylidene fluoride) sensor embedded inside the device as a tactile perceptron and a graphic designed as a visual perceptron. The primary role of the tactile perceptron is to initially recognize rice plants and provide a time point for image capture for visual perception. The main role of the visual perceptron is to extract features from the captured images and recognize rice plants again. The results of tactile and visual recognition were eventually fused to achieve accurate recognition of rice plants. CONCLUSION: The contact speed between the recognition perceptron and rice–weed was selected for the field performance test based on the real situation of paddy field operation. The results showed that the accuracy and reliability of rice plant recognition decreased as the travelling speed of the paddy field operation machine increased. The results of this study provide a basis for intelligent farm machinery operations in rice fields. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Rice fields are characterized by high algal production and dense mats of filamentous green algae, and they function as habitats for various aquatic organisms. However, how algal production supports the secondary production of aquatic consumers in rice fields has not been assessed. Herein, aquatic food web structures in two adjacent rice fields in northeastern Japan were examined using carbon and nitrogen stable isotope analyses. Filamentous algae often showed higher δ13C values (mean, −23.1‰ to −21.4‰) than other organic matter sources, including particulate organic matter, benthic microalgae, and soil organic matter (−30.1‰ to −25.4‰). A δ13C‐based isotopic mixing model estimated that among 19 taxa of herbivores and omnivores, most taxa depended on filamentous algae‐derived carbon (ca. >30%). Particularly, Peltodytes intermedius larvae, a specialist feeder for filamentous algae, showed the highest reliance (mean, 66.7%–80.0%). The microcrustacean, Ostracoda sp. also utilized a diet consisting of a substantial proportion of filamentous algae‐derived carbon (57.6%). Seven out of 10 carnivorous taxa showed reliance on filamentous algae‐derived carbon by >30%. Particularly, larvae of beetles (Berosus sp., Enochrus sp., and Hydrochara affinis) showed the highest reliance (40.2%–44.3%). They could assimilate filamentous algae‐based carbon by consuming herbivores, such as P. intermedius. Because fresh filamentous green algae were eaten less by aquatic consumers, the herbivores could consume decomposed filamentous algae rather than fresh ones. Our results suggest that filamentous algae are one of the major organic matter sources supporting secondary production in rice field food webs. [ABSTRACT FROM AUTHOR]

Rice paddies are wetland ecosystems recognized as important habitats for many organisms; however, the hybridization‐related extinction risk of native plant species has not been investigated in this system so far. Eclipta L. (Compositae) is a common paddy weed in Japan; however, its genetic composition might be altered due to the hybridization between the native E. thermalis and the closely related exotic E. alba. We examined Eclipta's genetic composition using 12 microsatellite markers (612 samples collected from 109 populations) and found (i) widespread geographical distribution of E. alba in Japan, (ii) hybridization with E. thermalis, and a large number of later‐generation hybrids, and (iii) widely varying situations among regions and populations. Eclipta alba appears to have invaded an open niche in northern Japan but has not yet reached southern Japan. Both E. alba and E. thermalis were found in central Japan; however, the latter had become rare due to hybridization‐mediated processes such as competition, and demographic and genetic swamping. Notably, endogenous and exogenous selection plays an important role in the invasion of E. alba, but to varying degrees among different areas. In summary, considering the genetic variability in E. thermalis, the genetic cluster of mainland Japan is in a highly critical situation due to the invasion of E. alba. [ABSTRACT FROM AUTHOR]

BACKGROUND: To maintain rice production and increase revenue, rice–duck (RD) farming is a contemporary ecological cycle technology that has been widely used in Asia. However, due to the clustering activity of duck flocks, the consequences of long‐term RD farming on rice growth at different scales are still unknown. Here, we studied RD farming using several different treatments (CK: conventional rice farming; RD1: 667 m2; RD2: 2000 m2; and RD3: 3333 m2). RESULTS: The results demonstrated that the maximum tillers, effective spikes, dry matter accumulation, and lodging index of rice under RD farming were significantly decreased by 17.9%, 9.8%, 14.8%, and 17.8%, respectively, which ultimately caused a significant decrease in yield of 10.6%. However, RD farming significantly increased root oxidation activity and the ear‐bearing tiller rate of rice by 25.5% and 11.1%, respectively, and improved yield stability. For different scales of RD farming, the lodging resistance index of RD1 was significantly lower than that of RD2 and RD3 by 10.0% and 15.2%, respectively, whereas the root oxidation activity and dry matter accumulation of RD2 were significantly higher than those of RD1 and RD3 by 11.1%, 4.7%, 8.6%, and 5.1%, respectively. For rice yield, there was no significant difference among the different scales. CONCLUSION: This long‐term experiment helped elucidate the complicated effects of RD farming at different scales on the growth and yield of rice. It is also critical to consider the economic advantages of different scales of RD farming to assess the impact of this system more thoroughly. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

SUMMARY: Increasing nutrient uptake and use efficiency in plants can contribute to improved crop yields and reduce the demand for fertilizers in crop production. In this study, we characterized a rice mutant, 88n which showed long roots under low nitrogen (N) or phosphorus (P) conditions. Low expression levels of N transporter genes were observed in 88n root, and total N concentration in 88n shoots were decreased, however, C concentrations and shoot dry weight in 88n were comparable to that in WT. Therefore, 88n showed high nitrogen utilization efficiency (NUtE). mRNA accumulation of Pi transporter genes was higher in 88n roots, and Pi concentration and uptake activity were higher in 88n than in WT. Therefore, 88n also showed high phosphorus uptake efficiency (PUpE). Molecular genetic analysis revealed that the causal gene of 88n phenotypes was OsbZIP1, a monocot‐specific ortholog of the A. thaliana bZIP transcription factor HY5. Similar to the hy5 mutant, chlorophyll content in roots was decreased and root angle was shallower in 88n than in WT. Finally, we tested the yield of 88n in paddy fields over 3 years because 88n mutant plants showed higher PUpE and NUtE activity and different root architecture at the seedling stage. 88n showed large panicles and increased panicle weight/plant. Taken together, a mutation in OsbZIP1 could contribute to improved crop yields. Significance Statement: To achieve environmentally safe agriculture increases in nutrient uptake efficiency (NUpE) and utilization efficiency (NUtE) are important aims to reduce the usage of fertilizer in crop production, while maintaining or increasing yields. In this study, we revealed that rice OsbZIP1 has functions in Phosphorus (P) and nitrogen (N) uptake and utilization, respectively, ultimately regulating panicle size and is thus a breeding target for improved yields under restricted nutrient conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Over the past decade, unmanned aerial vehicle (UAV) sprayers have emerged as valuable tools for pesticide application across various crops. Despite their increasing usage, the impact of several factors on spray performance and control efficacy in paddy fields warrants further investigation. This study examines atomization characteristics using a UAV spray test platform. Our evaluation of field spraying performance considers three UAV models, two nozzle types, two flight velocities, and adding methylated vegetable oil adjuvant (MVOA), in comparison with the electrical knapsack sprayer (EKS). RESULTS: Atomization characteristics demonstrated consistency within the downwash airflow field, but were influenced by spray solution, nozzle type, and spray pressure. The eight‐rotor UAV sprayer excelled over the quad‐rotor model in terms of spray deposition across both upper and lower rice canopies. The six‐rotor UAV exhibited enhanced spray deposition, droplet density, and coverage at a flight velocity of 4 m s−1. The choice of nozzle was pivotal; the flat fan nozzle produced finer droplets with desirable deposition and coverage, whereas the air‐induction nozzle created larger droplets with consistent coverage at various flight velocities. Adding MVOA improved the physicochemical properties of the spray and its performance, yielding a more uniform distribution. When compared with the EKS, UAVs showed lower deposition but comparable spray penetration. Control efficacy with the UAV sprayer was less effective against Mythimna separata but achieved 81% efficacy against Laodelphax striatellus within 7 days. CONCLUSION: This study demonstrates that UAV sprayers, particularly when combined with tank‐mix adjuvants and nozzle types, can be highly effective for controlling rice pests. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Ecosystems that offer several ecosystem services can be used as green infrastructure for human well‐being. In recent years, human activities have substantially engineered ecosystems to produce the desired ecosystem services. However, such efforts could lead to losses of other ecosystem services. Paddy fields are a seminatural ecosystem that can provide several ecosystem services other than rice production. Land consolidation in paddy fields aim to increase the efficiency of food production as a provisioning service, but it could depress the quality of wetland habitat as a supporting service. Recently, the Japanese government aimed to agricultural production with biodiversity conservation. Therefore, prioritizing a control strategy for future land consolidation is needed. Land consolidation work is effective for large areas and may incorporate the paddy field, previously a floodplain wetland that played a crucial role in regional biodiversity. However, land consolidation could result in the loss of this function. In this study, I investigated the spatial overlapping between land consolidation and paddy fields, which were previously natural floodplain wetlands in Kanagawa Prefecture, Japan. Here, terrain parameters and flow accumulation value (FAV), that can reflect wetland potential, along with the latest land use map, were used. The consolidation records in 1‐km cell for the whole of Kanagawa prefecture were used to test the hypothesis. Results showed that high FAV area with high wetland potential has large paddy fields and was heavily consolidated. Thus, there is need for drastic policy changes to align both food production and biodiversity in paddy fields in Japan. [ABSTRACT FROM AUTHOR]

Community assembly can change over time following variations in connectivity among habitats. Previous studies have demonstrated the influence of seasonal pulse floods on community structures by facilitating species dispersal, but the effects of short‐term flash floods have been poorly investigated. We investigated fish community structures before and after a short‐term flood in drainage ditches of paddy fields in the Kita River basin, Japan. The study sites were classified into three connectivity types, "Transient" (connected only during the flood, with a temporally disappearing vertical gap between drainage ditches and downstream rivers), "Connected" (always connected, without the vertical gap), and "Disconnected" (always not connected, with the vertical gap). The abundance of Misgurnus anguillicaudatus, the only species that dispersed from paddy fields to drainage ditches, increased after the flood irrespective of the connectivity types, although the total abundance of the other species significantly increased after the flood only in the "Transient" sites. The dissimilarity of species composition between the (n − 1)‐th and n‐th surveys at each site was consistently low in the "Connected" and "Disconnected" sites, whereas it rose just after the flood and gradually declined in the "Transient" sites. Species composition was significantly different among the connectivity types, indicating that some fish species need stable connectivity even during the non‐flood period. The results showed that the short‐term flood facilitated fish dispersal from paddy fields by the increased water discharge and that from downstream rivers by the temporary removal of vertical gap, emphasizing the importance of hydrological connectivity for biodiversity conservation in an agricultural landscape. [ABSTRACT FROM AUTHOR]

Paddy fields serve as significant reservoirs of soil organic carbon (SOC) and their potential for terrestrial carbon (C) sequestration is closely associated with changes in SOC pools. However, there has been a dearth of comprehensive studies quantifying changes in SOC pools following extended periods of rice cultivation across a broad geographical scale. Using 104 rice paddy sampling sites that have been in continuous cultivation since the 1980s across China, we studied the changes in topsoil (0–20 cm) labile organic C (LOC I), semi‐labile organic C (LOC II), recalcitrant organic C (ROC), and total SOC. We found a substantial increase in both the content (48%) and density (39%) of total SOC within China's paddy fields between the 1980s to the 2010s. Intriguingly, the rate of increase in content and density of ROC exceeded that of LOC (I and II). Using a structural equation model, we revealed that changes in the content and density of total SOC were mainly driven by corresponding shifts in ROC, which are influenced both directly and indirectly by climatic and soil physicochemical factors; in particular temperature, precipitation, phosphorous (P) and clay content. We also showed that the δ13CLOC were greater than δ13CROC, independent of the rice cropping region, and that there was a significant positive correlation between δ13CSOC and δ13Cstraw. The δ13CLOC and δ13CSOC showed significantly negative correlation with soil total Si, suggesting that soil Si plays a part in the allocation of C into different SOC pools, and its turnover or stabilization. Our study underscores that the global C sequestration of the paddy fields mainly stems from the substantial increase in ROC pool. [ABSTRACT FROM AUTHOR]

Finger millet (Eleusine coracana (L.) Gaertn.) is an important cereal crop grown in most parts of Asia and Africa owing to its ability to adapt to stressful environments. The objective of this study was to examine the effect of waterlogging on photosynthesis and growth of finger millet. Plants were subjected to waterlogging by keeping pots filled with water from June 16 (transplanting) until November 12 (harvesting) in 2021 in Tokyo. After being subject to 13 days of waterlogging, net photosynthetic rate (Pn) decreased by 10.1% due to reduced stomatal conductance (gs), transpiration rate, and relative chlorophyll content (SPAD). From July to September, long‐term waterlogging increased Pn in the range of 4.9%–26.3%. The alleviation of high temperature, increase in SPAD and gs, and other nonstomatal components were implicated as the cause of increased Pn in summer. These findings suggest that the effect of waterlogging on photosynthesis varies with the duration of waterlogging or the growing season. Plant height was significantly reduced by 27.9% during the first 13 days of waterlogging and remained lower throughout the waterlogging treatment than in irrigated conditions. Waterlogging also caused other morphological changes, such as a significant increase in the number of tillers (63.2%) and a 16.7% increase in the number of panicles. Grain yield decreased by 13.6%, but the reduction was not significant. Overall, finger millet has the potential to tolerate waterlogging and is a promising crop for both paddy and field farming. Core Ideas: Waterlogging initially reduced stomatal conductance and SPAD, resulting in decreasing net photosynthetic rate.Waterlogging could improve photosynthetic gas exchange in finger millet during summer.Waterlogging caused morphological changes, such as a decrease in plant height and an increase in tiller number.Grain yield of finger millet was not significantly decreased under waterlogging conditions.Finger millet has the potential to tolerate waterlogging stress. [ABSTRACT FROM AUTHOR]

Thailand is the foremost global producer of rice, benefiting from its hot and humid climate which results in harvested rice with a high moisture content. This promotes the rapid growth of microorganisms that harm the paddy. Consequently, the utilization of drying techniques is necessary to uphold the quality of the product. For the sake of efficiency and dependability, forced draft convection drying is commonly utilized, despite its high energy consumption. In general, the paddy is subjected to the flow of hot air, which exits the drier at a reduced temperature, leading to energy dissipation. Heat pipes have been widely employed to reclaim wasted energy through the preheating of fresh air, owing to their straightforward design and lack of reliance on external power sources. Nevertheless, there has been a scarcity of research conducted on the utilization of the oscillating heat pipe in these particular applications. Thus, a pilot‐scale oscillating heat pipe is utilized in this study. The primary aim of this study is to evaluate the efficiency of waste heat recovery using the recently developed oscillating heat pipe, as well as the resulting energy conservation. Various thicknesses of rice paddy layers are examined to compare the duration it takes for them to dry. It is seen that the drying time increases as the bulk of the paddy increases. When the layer thickness is increased, a multimodal drying rate behavior is observed which is due to the fact that when the heated air ascends, it repeatedly heats each layer of the grain. The study focuses on analyzing the temperature profiles at the heat pipe and within the evacuated air. The rate of heat recovery is also computed. An investigation is conducted to determine the energy savings achieved through the use of heat pipes. The results indicate a decrease in energy consumption ranging from 39.4% to 63.7%. This study showcases the utilization of a research‐scaled oscillating heat pipe in the rice drying procedure, serving as a foundation for the future enhancement of the heat recovery system in industrial rice drying. Practical applications: Thailand is the world's top rice producers and because it is hot and humid, the harvested rice has a high moisture content, which encourages the growth of bacteria. In most cases, forced draft convection drying is used, which uses a large amount of energy. In general, this is due to energy loss in the exhaust. Heat pipes have been widely employed to recover wasted energy. However, research on the utilization of oscillating heat pipes in such applications has been limited. Hence, a pilot‐scale oscillating heat pipe is used in this work to evaluate the efficacy of waste heat recovery as well as the energy savings. The drying time is shown to increase with the thickness of the paddy layer. The temperature profiles at the heat pipe and in the evacuated air, as well as the heat recovery rate, are investigated. The results show an energy reduction of 41.7%–53.9%. [ABSTRACT FROM AUTHOR]

Rice‐crayfish (RC) integrated cultivation, as a sustainable agricultural system, could significantly improve soil fertility. However, the soil quality under the long‐term RC farming system is still unclear. To examine the effects of RC cultivation on soil quality in paddy fields, this study utilized an integrated soil quality index (SQI) for examining the soil quality at different soil profiles (0–10, 10–20, and 20–30 cm depth) in rice monoculture (RM) and RC farming systems (after 1, 6, 10, and 15 years) scattered in Nanxian County, Hunan Province, China. The minimum datasets for evaluating soil quality were assembled using the soil pH, bulk density, total nitrogen, microbial biomass carbon, microbial biomass nitrogen, and β‐d‐glucosidase. The findings demonstrated that soil quality was greatly impacted by RC farming, which improved with the increase of years under RC management. The soil quality of 10‐ and 15‐year RC farming systems were significantly higher than RM system. Besides, soil quality declined with increasing soil depth. The SQI value, which may be used as an indicator to assess the soil quality of RC systems, was dominated by total nitrogen, which contributed 27.60% to the SQI value. On the whole, long‐term RC farming affected the soil quality of paddy fields through management methods including non‐rice season flooding, feeding, and no tillage. Through this study, it was found that MDS and SQI composed of appropriate physical, chemical, and biological indicators could more objectively analyze the soil quality of long‐term RC system and provide guidance for sustainable development of RC farming. [ABSTRACT FROM AUTHOR]

The Vietnam Mekong Delta (VMD) is threatened by increasing saltwater intrusion due to diminishing freshwater availability, land subsidence, and climate change induced sea level rise. Through irrigation, saltwater can accumulate in the rice fields and decrease rice production. The study aims at evaluating topsoil salinity and examining a potential link between topsoil salinity and rice production systems in a case study in the Tra Vinh province of the VMD. For this, we applied two geophysical methods, namely, 3D electrical resistivity tomography (ARES II) and electromagnetic induction (EM38‐MK2). 3D ARES II measurements with different electrode spacings were compared with EM38‐MK2 topsoil measurements to evaluate their respective potential for monitoring topsoil salinity on an agricultural scale and the relationship between land‐use types and topsoil salinity. Results show that EM38‐MK2 is a rapid and powerful tool for obtaining high‐resolution topsoil salinity maps for rice fields. With ARES II data, 3D maps up to 40 m depth can be created, but compared with EM38‐MK2 topsoil maps, topsoil salinity was underestimated due to limitations in resolution. Salt contamination of above 300 mS m−1 was found in some double‐cropped rice fields, whereas in triple‐cropped rice fields salinity was below 200 mS m−1. Results clearly show a relation between topsoil salinity and proximity to the saline water sources; however, a clear link between rice production and topsoil salinity could not be established. The study proved that geophysical methods are useful tools for assessing and monitoring topsoil salinity at agricultural fields scale in the VMD. [ABSTRACT FROM AUTHOR]

Diamide insecticides are widely used in rice paddies and pose a potential threat to aquatic organisms. However, the risk research related to their application in major rice‐producing areas is very limited, especially mesocosm research to simulate the impact on aquatic ecosystems of long‐term exposure, as well as exposure analysis based on local models and local scenarios. To assess potential risks from a novel diamide insecticide (tetrachlorantraniliprole) to aquatic nontarget organisms in the field over long‐term exposure, an outdoor mesocosm study was performed, and the environmental concentrations were predicted by the multimedia paddy‐pond model (TOPRICE). The mesocosm experiment showed that tetrachlorantraniliprole mainly stayed in the aqueous phase after entering the water body. Although the chemical dissipated quickly in the aqueous phase (half‐life of 0.79–1.5 days), it showed toxic effects on zooplankton communities. Cladocerans, represented by Simocephalus vetulus, were most sensitive to tetrachlorantraniliprole stress. Significant short‐term toxicity to cladocerans occurred in all treatment groups, but all recovered within 8 weeks except for the highest concentration group (30.0 µg /L). Based on the ecological recovery results, 7.74 µg tetrachlorantraniliprole/L (nominal concentration, 10.0 µg /L) is suggested to be the no‐observed‐ecological‐adverse‐effect concentration (NOEAEC) for the zooplankton community. When this NOEAEC was compared with predicted environmental concentrations (PECs; the PECs in natural ponds simulated by the TOPRICE model for 148 application scheme combinations in major rice‐producing areas), a relatively high risk of applying tetrachlorantraniliprole during the rice tillering stage was found. The present study makes a positive contribution to the hypothesis that the current Tier 1 approaches for global acute risk assessment have a sufficient protective effect for assessing the risk of tetrachlorantraniliprole to aquatic organisms. Also, the present results should help us to gain a fuller understanding of the ecological risk of diamide insecticides in aquatic ecosystems and their rational application schemes. Environ Toxicol Chem 2024;43:429–439. © 2023 SETAC [ABSTRACT FROM AUTHOR]

Denitrification plays a critical role in soil nitrogen (N) cycling, affecting N availability in agroecosystems. However, the challenges in direct measurement of denitrification products (NO, N2O, and N2) hinder our understanding of denitrification N losses patterns across the spatial scale. To address this gap, we constructed a data‐model fusion method to map the county‐scale denitrification N losses from China's rice fields over the past decade. The estimated denitrification N losses as a percentage of N application from 2009 to 2018 were 11.8 ± 4.0% for single rice, 12.4 ± 3.7% for early rice, and 11.6 ± 3.1% for late rice. The model results showed that the spatial heterogeneity of denitrification N losses is primarily driven by edaphic and climatic factors rather than by management practices. In particular, diffusion and production rates emerged as key contributors to the variation of denitrification N losses. These findings humanize a 38.9 ± 4.8 kg N ha−1 N loss by denitrification and challenge the common hypothesis that substrate availability drives the pattern of N losses by denitrification in rice fields. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Rice dwarf virus (RDV)‐induced rice plant volatiles (E)‐β‐caryophyllene and 2‐heptanol modulate the olfactory behavior of RDV insect vectors that promote viral acquisition and transmission. However, it remains elusive whether these two volatiles could influence the behaviors of the natural enemies of RDV insect vectors. Herein, we determined the effects of these two volatiles on the olfactory and predatory behaviors of Cyrtorhinus lividipennis (Hemiptera: Miridae), an important predator of RDV insect vectors in rice paddies. RESULTS: The results showed that C. lividipennis preferred RDV‐infected rice plant odors over RDV‐free rice plant odors. C. lividipennis was attracted by (E)‐β‐caryophyllene, but showed no behavioral responses to 2‐heptanol. The attraction of (E)‐β‐caryophyllene towards C. lividipennis was further confirmed using oscas1 rice plants, which do not release (E)‐β‐caryophyllene in response to RDV infection, through a series of complementary assays. The oviposition preference of the RDV vector insect Nephotettix cincticeps (Hemiptera: Cicadellidae) showed no significant difference between RDV‐infected and RDV‐free wild‐type plants, nor between oscas1‐RDV and oscas1 plants. However, the predation rate of C. lividipennis for N. cincticeps eggs on RDV‐infected plants was higher than that on RDV‐free plants, whereas there was no significant difference between oscas1‐RDV and oscas1 plants. CONCLUSION: (E)‐β‐caryophyllene induced by RDV attracted more C. lividipennis to prey on N. cincticeps eggs and played a crucial role in plant–virus–vector–enemy interactions. These novel findings will promote the design of new strategies for disease control by controlling the populations of insect vectors, for example recruiting more natural enemies by virus‐induced plant volatiles. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Recently, suspected cyhalofop‐butyl‐resistant populations of allohexaploid weed Echinochloa crus‐galli var. crus‐galli were discovered in rice fields in Aichi Prefecture, Japan. Analyzing the target‐site ACCase genes of cyhalofop‐butyl helps understand the resistance mechanism. However, in E. crus‐galli, the presence of multiple ACCase genes and the lack of detailed gene investigations have complicated the analysis of target‐site genes. Therefore, in this study, we characterized the herbicide response of E. crus‐galli lines and thoroughly characterized the ACCase genes, including the evaluation of gene mutations in the ACCase genes of each line. RESULT: Four suspected resistant lines collected from Aichi Prefecture showed varying degrees of resistance to cyhalofop‐butyl and other FOP‐class ACCase inhibitors but were sensitive to herbicides with other modes of action. Through genomic analysis, six ACCase loci were identified in the E. crus‐galli genome. We renamed each gene based on its syntenic relationship with other ACCase genes in the Poaceae species. RNA‐sequencing analysis revealed that all ACCase genes, except the pseudogenized copy ACCase2A, were transcribed at a similar level in the shoots of E. crus‐galli. Mutations known to confer resistance to FOP‐class herbicides, that is W1999C, W2027C/S and I2041N, were found in all resistant lines in either ACCase1A, ACCase1B or ACCase2C. CONCLUSION: In this study, we found that the E. crus‐galli lines were resistant exclusively to ACCase‐inhibiting herbicides, with a target‐site resistance mutation in the ACCase gene. Characterization of ACCase loci in E. crus‐galli provides a basis for further research on ACCase herbicide resistance in Echinochloa spp. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Environmental changes associated with urbanisation can exert pressure that facilitates both adaptations and plastic responses in plants. Field surveys or common garden experiments (CGE) alone cannot differentiate between the observed phenotypic traits resulting from plastic responses versus evolutionary adaptations to urban environments.We conducted a field survey of habitat environmental factors and four vegetative traits in 12 Commelina communis populations along an urban–rural gradient in the Osaka‐Kobe megacity area. We collected seedlings from six of the 12 populations, transplanted them into a greenhouse, and measured six vegetative traits. We investigated correlations between pairs of measured traits in both the field survey and CGE.Plant height and leaf area increased significantly in increasingly developed land areas (DLA) in the field survey, whereas no such variations were found in the CGE, suggesting that the observed phenotypic variation was due to a plastic response to urban eutrophication. Leaf number and specific leaf area (SLA) significantly decreased with increasing DLA in the CGE, suggesting the adaptation of these traits to urban environments. Positive correlations between plant height and leaf area were only observed in urban populations in both the field survey and CGE, indicating the evolution of this trait correlation in urban environments.It has been suggested that urban environments promote both plastic response and genetic divergence of a set of traits in native plants. Our findings suggest that low leaf number, SLA, and positive plant height–leaf area correlations have evolved. In addition, larger plant size is achieved via phenotypic plasticity in urban environments. [ABSTRACT FROM AUTHOR]

The application of biochar and nitrogen fertilizer can increase rice yield, soil organic carbon (SOC) storage and reduce greenhouse gas (GHG) emissions. However, few studies have systematically evaluated the carbon footprint (CF) and net ecosystem economic benefits (NEEB) of paddy ecosystems under long‐term application of biochar and nitrogen fertilizer. Here, the life cycle assessment method was used to quantify the CF and NEEB of paddy fields under different biochar and nitrogen fertilizer application rates in 7 years. Three biochar rates of 0 (B0), 4.5 (B1) and 13.5 t ha−1 year−1 (B2) and two nitrogen fertilizer rates of 0 (N0) and 300 kg ha−1 year−1 (N) were set. The results showed that B2 significantly increased methane (CH4) emission by 38%, decreased nitrous oxide (N2O) emission by 29%, and significantly increased global warming potential by 27% compared with B0. Besides that, biochar application significantly increased ΔCSOC by 87%–173% and reduced CF by 1.6–1.8 Mg CO2 eq ha−1. Among them, CH4 and N2O emissions contributed 46%–95% of total GHG emissions, and the production and transportation of nitrogen fertilizer and biochar contributed 17%–52% of total GHG emissions. Nitrogen fertilizer application can significantly increase rice yield by 85% compared to the N0, which could bring the largest NEEB. Biochar application had a negative influence on the NEEB regardless of N application. This might be attributable to the fact that the economic gains from increased rice production and SOC caused by biochar cannot outweigh the high cost of biochar. These results suggest that the biochar application can significantly improve the SOC sequestration and reduce the CF, but also had negative effect on NEEB in paddy filed. [ABSTRACT FROM AUTHOR]

Bayesian network (BN) models are increasingly used as tools to support probabilistic environmental risk assessments (ERAs), because they can better account for uncertainty compared with the simpler approaches commonly used in traditional ERA. We used BNs as metamodels to link various sources of information in a probabilistic framework, to predict the risk of pesticides to aquatic communities under given scenarios. The research focused on rice fields surrounding the Albufera Natural Park (Valencia, Spain), and considered three selected pesticides: acetamiprid (an insecticide), 2‐methyl‐4‐chlorophenoxyacetic acid (MCPA; a herbicide), and azoxystrobin (a fungicide). The developed BN linked the inputs and outputs of two pesticide models: a process‐based exposure model (Rice Water Quality [RICEWQ]), and a probabilistic effects model (Predicts the Ecological Risk of Pesticides [PERPEST]) using case‐based reasoning with data from microcosm and mesocosm experiments. The model characterized risk at three levels in a hierarchy: biological endpoints (e.g., molluscs, zooplankton, insects, etc.), endpoint groups (plants, invertebrates, vertebrates, and community processes), and community. The pesticide risk to a biological endpoint was characterized as the probability of an effect for a given pesticide concentration interval. The risk to an endpoint group was calculated as the joint probability of effect on any of the endpoints in the group. Likewise, community‐level risk was calculated as the joint probability of any of the endpoint groups being affected. This approach enabled comparison of risk to endpoint groups across different pesticide types. For example, in a scenario for the year 2050, the predicted risk of the insecticide to the community (40% probability of effect) was dominated by the risk to invertebrates (36% risk). In contrast, herbicide‐related risk to the community (63%) resulted from risk to both plants (35%) and invertebrates (38%); the latter might represent (in the present study) indirect effects of toxicity through the food chain. This novel approach combines the quantification of spatial variability of exposure with probabilistic risk prediction for different components of aquatic ecosystems. Environ Toxicol Chem 2024;43:182–196. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Future phosphorus (P) shortages could seriously affect terrestrial productivity and food security. We investigated the changes in topsoil available P (AP) and total P (TP) in China's forests, grasslands, paddy fields, and upland croplands during the 1980s–2010s based on substantial repeated soil P measurements (63,220 samples in the 1980s, 2000s, and 2010s) and machine learning techniques. Between the 1980s and 2010s, total soil AP stock increased with a small but significant rate of 0.13 kg P ha−1 year−1, but total soil TP stock declined substantially (4.5 kg P ha−1 year−1) in the four ecosystems. We quantified the P budgets of soil–plant systems by harmonizing P fluxes from various sources for this period. Matching trends of soil contents over the decades with P budgets and fluxes, we found that the P‐surplus in cultivated soils (especially in upland croplands) might be overestimated due to the great soil TP pool compared to fertilization and the substantial soil P losses through plant uptake and water erosion that offset the P additions. Our findings of P‐deficit in China raise the alarm on the sustainability of future biomass production (especially in forests), highlight the urgency of P recycling in croplands, and emphasize the critical role of country‐level basic data in guiding sound policies to tackle the global P crises. [ABSTRACT FROM AUTHOR]

Exploring the relationship between soil organic carbon (SOC) and different farmland utilization types can contribute to achieving carbon neutrality in agriculture. Over the past few decades, numerous researchers have conducted a multitude of studies on the effects of farmland utilization types on SOC in China, and these studies have yielded a wealth of data from field experiments. However, these experiments are limited in that they lack sufficient quantitative analyses of studies conducted on regional or national scales. In this study, we analyzed the three most common farmland utilization types (paddy field [PF], dry land [DL], and vegetable field [VF]) in China using a national‐scale meta‐analysis and included data from 108 observations from 28 studies in the field. In this meta‐analysis, we conducted three comparisons (control vs. treatment): (a) PF versus DL, (b) PF versus VF, and (c) DL versus VF. The results showed that in comparison (a), DL had a significantly lower SOC than PF (ln R++ = −0.463, 95% confidence intervals [CIs] = −0.580 ~ −0.345), with DL showing 37.1% lower SOC than PF. In comparison (b), although there was no statistically significant difference between PF and VF (ln R++ = −0.078, 95% CIs = −0.167 ~ 0.011), VF had 7.5% lower SOC than PF. In comparison (c), VF had significantly higher SOC than DL (ln R++ = 0.227, 95% CIs = 0.147 ~ 0.307), with VF showing 25.5% higher SOC than DL. It should be noted that the effects of farmland utilization types on SOC content observed in China varied depending on different factors such as the regions, climatic conditions, and cropping systems. In conclusion, SOC content could be affected by farmland utilization types. Therefore, in order to promote the development of low‐carbon agriculture in China, it is important to consider farmland utilization types in agricultural production, as well as to consider carbon budgets, food security, and field practices to maximize agronomic and environmental benefits. [ABSTRACT FROM AUTHOR]

The straw incorporation in paddy fields exacerbates the reductive toxicity caused by flooding during the rice tillering stage in cold regions. Mid-drainage can alleviate reductive toxicity, while nitrogen fertilizer (NF) application can enhance the drought resistance of rice. However, there is still a lack of convincing evidence about the types of reductive toxicity and appropriate draining thresholds with straw incorporation. A field experiment was conducted in northeast China to investigate the reductive toxicity of paddy fields caused by flooding and straw incorporation. Primarily, the study aimed to investigate the reduction of toxicity caused by straw incorporation. Additionally, the investigation verified the role of varying NF (0, 50, 100, 150 kg N ha-1) in conjunction with mid-season drainage (-15 cm) to mitigate soil reductive toxicity while preserving root activity. Before mid-season drainage, the contents of soil total amount of reductive matter, active reductive matter, Fe2+, and Mn2+ were 5.1-5.9 cmol kg-1, 3.2-3.9 cmol kg-1, 399.4-410.1 mg kg-1 and 290.3-340.1 mg kg-1, respectively. Mid-season drainage of 15 cm depth decreased the total amount of reductive matter, active reductive matter and Fe2+ content by 51.8%, 56.0% and 29.6%, respectively. However, upon rewetting, the content of reductive substances reverted to pre-drainage levels. Drainage led to a reduction in soil organic acid content by 56.6-78.8% and an increase in rice root activity by 160-290%. While increased NF application correlated with higher rice root activity, a significant yield increase was only observed within the range of 0-100 kg ha-1. In summary, an alternate wetting and drying threshold of -15 cm in combination with 100 kg ha-1 of NF rate significantly increased root activity and reduced reductive toxicity of the tillage layer without decreased rice yield. The reductive substance content rebounded to the pre-drainage level after reflooding in the subsequent growth stage. Therefore, to minimize the reductive toxicity and methane emission caused by straw incorporation, rice fields can be drained to a depth of 15 cm during mid-season drainage. Additionally, the fields should be drained several times in the following growth stage. [ABSTRACT FROM AUTHOR]

To enhance rice yields, synthetic nitrogen (N) fertilizers are often applied in rice paddy fields. Under waterlogged conditions, denitrification, anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA) are the main N transformation processes. However, the effects of longterm fertilization on the dissimilatory nitrate reduction processes remain largely unclear. Here, we investigated rates of denitrification, anammox and DNRA and the abundance of bacterial and nitrate reduction-related genes (16S rRNA, narG, nirK, nirS, nosZ and hzsB) in rice paddy fields under different fertilization regimes [i.e., non-fertilization (CK), NPK fertilization (NPK) and NPK fertilization plus straw returning (NPKS)]. The rates of denitrification, anammox and DNRA in the CK treatment were 46.18, 0.35 and 1.29 nmoL N g-1 h-1, respectively, which were significantly (p < .05) increased by 7.32%-27.78%, 2.45-4.12 folds and 1.01-13.23 folds by NPK and NPKS treatments. This was largely consistent with the increased bacterial and nitrate reduction-related gene abundances in the NPK and NPKS treatments. In addition, NPKS also significantly increased the relative contribution of DNRA to the total nitrate reduction relative to NPK and CK treatments, indicating that NPKS was more beneficial to N retention in the paddy field. Changes in rates of dissimilatory nitrate reduction processes in response to NPK and NPKS treatments were correlated to variations of soil total N, ammonium contents, pH, soil organic carbon (SOC) contents and nitrate reduction-related genes, among which SOC contents had the highest explanation. Specifically, fulvic-like compounds, alkyl C and methoxyl and nitrogen-alkyl C were the key components determining denitrification, anammox and DNRA rates, respectively. Overall, our study suggests that long-term NPK and NPKS fertilization stimulate rates of dissimilatory nitrate reduction processes mainly by altering soil C components and NPKS is more effective in maintaining soil fertility in the paddy field. [ABSTRACT FROM AUTHOR]

Spot spraying applications offer the opportunity to target specific weeds in a field, while simultaneously reducing herbicide usage and increasing the long‐term efficacy of chemical control options. The study is focused on controlling California weedy rice accessions (Oryza spp.) and problematic grass weeds with a spot spray application of clethodim in a flooded rice system. The efficacy of incorporating nonionic surfactant to clethodim applications was also assessed. Dose‐response experiments were carried out in a greenhouse on five weedy rice accessions, common grass rice weeds, and cultivated rice varieties L207, M105, M206, M209, M211, and S102 to determine the dose needed to affect these populations. Clethodim was applied in a field setting to assess spot spraying efficacy, the possibility of herbicide dispersion in the water, and crop injury. Clethodim successfully controlled weedy rice and grasses in the greenhouse. The effective rates to control 90% of the five test populations (ED90) were between 51 and 74 g ai ha−1 clethodim for weedy rice accessions. Adding nonionic surfactant to clethodim increased its efficacy by 1.6‐ to 1.9‐fold. Cultivated rice varieties did not exhibit any tolerance to clethodim, however, spot spraying applications at 150 g ai ha−1 clethodim did not cause any dispersion in the field. Clethodim spot spray application was effective both at the three‐ to four‐leaf growth stage and tillering growth stage for weedy rice. Core Ideas: Spot spray herbicide application successfully controlled weedy rice.Adding nonionic surfactant (NIS) increased the efficacy of clethodim.Clethodim at labeled rate did not cause rice injury outside the spot spray area in rice field.Clethodim spot spray was effective both at the three to four‐leaf growth stage and tillering growth stage for weedy rice. [ABSTRACT FROM AUTHOR]

Biochar has been suggested as a soil supplement to improve soil fertility. The world is covered in microplastics (MPs). A pot greenhouse experiment was carried out to examine the effects of polystyrene (PS), sugarcane bagasse biochar (SBB), and their interactions (PS × SBB) on the CO2 emission and rice yield in a rice paddy calcareous soil. The largest CO2 emissions occurred 35–40 days following rice planting, which corresponds to the tillering stages of rice growth. Higher CO2 emissions were detected after SBB treatment. Our findings showed that applying PS increased CO2 emissions in our soil samples. Our research revealed that adding SBB can boosted the negative effects of PS in the soil. The co‐application of SBB and PS increased PS's stimulation of the CO2 emissions. We infer that PS‐SBB interactions have an impact on global warming potential, microbial community activity, and CO2 emissions. Both SBB rates resulted in a significant increase in biomass and rice grain. Our research indicates that PS has a detrimental effect on rice grain output and biomass, but that the addition of SBB can slightly lessen these effects. [ABSTRACT FROM AUTHOR]

Rice yellow mottle virus (RYMV) is widespread in mainland Africa and adjoining islands but to date its occurrence in Zambia is unknown. In March 2022, field surveys were conducted in Luapula, Northern, Western and Eastern provinces of Zambia to determine the occurrence of RYMV and its genetic relationship with global isolates of the virus. Thirty‐three paddy rice fields were visited and 108 leaf tissue samples were collected for analysis. The incidence of yellow mottle symptoms ranged from 25% to 43% in 10 (30.3%) of 33 fields and RYMV was detected in 35 (32.4%) of 108 samples by RT‐PCR with virus‐specific primers. A subset of 27 RYMV‐positive samples was constituted from which full‐length (720 bp) coat protein (CP) regions were amplified followed by bidirectional Sanger sequencing. Phylogenetic analysis of the CP cistron revealed distinct clustering of the isolates from Zambia in a monophyletic clade as subtype of the RYMV strain S4. Three isolates were randomly selected and used to obtain complete RYMV genomes of 4448–4449 nucleotides (nt). Comparative analysis of both the CP and the complete RYMV genomes from Zambia with their corresponding sequences in GenBank revealed that they shared 92%–93.2% nt identities with strain S4 isolates. These results confirm for the first time occurrence of RYMV strain S4 in Zambia and further reinforce the need for phytosanitary vigilance to safeguard rice production in Zambia. [ABSTRACT FROM AUTHOR]

Alternate wetting and drying irrigation (AWD) has been shown to decrease water use and trace gas emissions from paddy fields. Whereas genotypic water use shows little variation, it has been shown that rice varieties differ in the magnitude of their methane emissions. Management and variety‐related emission factors have been proposed for modelling the impact of paddy production on climate change; however, the magnitude of a potential reduction in greenhouse gas emissions by changing varieties has not yet been fully assessed. AWD has been shown to affect genotypic yields and high‐yielding varieties suffer the greatest loss when grown under AWD. The highest yielding varieties may not have the highest methane emissions; thus, a potential yield loss could be compensated by a larger reduction in methane emissions. However, AWD can only be implemented under full control of irrigation water, leaving the rainy seasons with little scope to reduce methane emissions from paddy fields. Employing low‐emitting varieties during the rainy season may be an option to reduce methane emissions but may compromise farmers' income if such varieties perform less well than the current standard. Methane emissions and rice yields were determined in field trials over two consecutive winter/spring seasons with continuously flooded and AWD irrigation treatments for 20 lowland rice varieties in the Mekong Delta of Vietnam. Based on the results, this paper investigates the magnitude of methane savings through varietal choice for both AWD and continuous flooding in relation to genotypic yields and explores potential options for compensating farmers' mitigation efforts. [ABSTRACT FROM AUTHOR]

Land‐use conversion has a great impact on soil pore structure. However, the variation of pore structure and the related driving factors following land‐use conversion are still in need of further interpretation. In this study, the pore structure of millimetric intact aggregates as well as centimetric undisturbed soil cores collected from paddy fields (PF) and vegetable fields converted from paddy fields for 5 years (VF‐5), 13 years (VF‐13), and 20 years (VF‐20) was quantified by dual‐scale x‐ray tomography. Results revealed that the pore structure at the aggregate and soil core scales responded differently after the paddy fields were converted to vegetable fields. Imaged porosity and pore connectivity of aggregates increased slightly following land‐use conversion. Those properties increased significantly within soil cores. Compared with the paddy field aggregates, the porosity of elongated pores with larger diameters markedly increased in vegetable field aggregates, suggesting an enhancement in the accessibility of air, water, and nutrients. At the soil core scale, the alteration of pore structure was mainly attributed to the shift of the soil environment, the change of tillage operation, and the plantation of different crops. The shift of rice to vegetable plantation significantly altered the length and tortuosity of the intermediate branch pores. Importantly, the land‐use change created a more drainable pore structure due to the significant increase of pore connectivity at the soil core scale, which is suitable for vegetable plantations. These findings are crucial for evaluating and interpreting the microscale pore structure change following land‐use conversion. [ABSTRACT FROM AUTHOR]

Intensification of cultivation methods and land‐use types, particularly in the face of climate change, has steadily weakened the habitat function of rice fields for waterbirds.Intermediate egrets (Ardea intermedia) are highly dependent on rice field habitats. Here, we examine the effect of a shift from rice monoculture to rice–barley double cultivation on the use of rice fields by intermediate egrets in South Korea. Rice–barley double cultivation has been increasing steadily in the southern region of South Korea due to changes in the rice growth period under climate change and maximization of economic benefits.We studied rice fields to determine the effect of the rice–barley double cultivation area on the abundance of intermediate egrets on the regional scale and their potential distribution pattern in response to double cultivation in relation to climate change using national‐scale climate, altitude and land cover data from 1 May to 23 June 2018.Compared to the irrigation practices used for rice monoculture, irrigation was stopped for some time in rice–barley double cultivation prior to planting, compromising the role of rice fields as a food ground for intermediate egrets. The potential abundance of intermediate egrets rapidly decreased by half when the double cultivation area increased to >40% of the total rice‐field area, and was less than one individual if the area increased to >80%. Furthermore, according to climate change projections, by 2100, the double cultivation area would account for 75.74% of the predicted range of intermediate egret foraging ground.Synthesis and applications. Double cultivation areas should be <40% of existing rice fields to minimize the impact of the change in cultivation practices. This approach can also convert rice fields to other types of land use. Consequently, appropriate conservation and management measures may be developed to maintain suitable habitats despite rapidly changing cultivation practices resulting from climate change. [ABSTRACT FROM AUTHOR]

The relationship between the gut bacterial communities of carabid beetles and their habitats holds implications for understanding ecological dynamics. This study examined the gut bacterial communities of two carabid beetle species, Chlaenius pallipes and Pheropsophus jessoensis, in terraced and flat paddy fields. Differences in gut bacterial communities were evident at the species level and were based on habitat. Specifically, P. jessoensis had a greater presence of Firmicutes and Proteobacteria in terraced fields but more Actinobacteria in flatland fields. In comparison, C. pallipes consistently showed high levels of Firmicutes in both habitats. These differences were reflected at class and genus levels, emphasizing the role of host specificity in shaping gut microbiota. Alpha diversity metrics indicated that P. jessoensis hosted a more diverse bacterial community than C. pallipes. Terraced fields, however, showed slightly reduced diversity in P. jessoensis, suggesting environmental effects on microbial populations. Beta diversity analysis using Bray–Curtis distances differentiated the bacterial communities of the two beetles. Multivariate analysis of variance reinforced these findings. Insights from the Sloan neutral model indicate that environmental factors predominantly influence bacterial community assembly through stochastic processes. Functionally, metabolism was highlighted, indicating the role of gut bacteria in beetle metabolic processes. Notably, energy metabolism varied between field types, revealing environmental effects on gut bacterial functions. This study offers in‐depth insights into interactions between host‐specific and environmental factors influencing gut bacterial communities of carabid beetles, contributing to a broader understanding of microbial ecology and the roles of environment and host in microbiota dynamics. [ABSTRACT FROM AUTHOR]

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The methane (CH4) production process in paddy fields varies depending on different cropping modes. However, there is limited knowledge on the changes in anaerobically produced CH4 isotopic ratios (δ13CH4), the methanogenic pathways, and the dominant communities of methanogens in paddy soils under different modes. To address this, we conducted experiments using anaerobic incubation methods, stable carbon isotope fractionation through inhibition studies with fluoromethane, and high‐throughput sequencing. These methods allowed us to measure the CH4 production potential (MPP), the relative contribution of acetoclastic methanogenesis to CH4 production (fac), and the composition of the methanogen community in paddy soils under three typical cropping modes: Rice‐Wheat (RW), Rice‐Fallow (RF), and Double‐Rice (DR) in China. The results showed that MPP was 30.7 μg CH4 g−1 d−1 in DR soil, around 57% and 66% higher than that in RW and RF soils, respectively, possibly due to the lower pH, clay content, and higher abundance of the mcrA gene. Moreover, RF soil had the highest value of produced δ13CH4 (−43.9‰) but the lowest value of produced δ13CO2 (−26.3‰). Based on the carbon isotope fractionation associated with methanogenesis via H2/CO2 reduction (1.049–1.062), the values of fac estimated in the RF soil (80%–98%) were much higher than that in the RW (39%–60%) and DR soils (52%–75%). This could be supported by the finding showing that Methanosarcina, the acetoclastic methanogens, were dominant in RF soil, while Methanosarcina and Methanobacterium (the hydrogenotrophic methanogens) dominated in RW and DR soils. Redundancy analysis revealed that the community structure of methanogens was significantly affected by soil pH. The findings suggest that differences in the abundance and composition of methanogens, possibly driven by soil pH, play a key role in regulating methanogenesis in the paddy soils, and further provide valuable insights into the process of CH4 production in different cropping modes. Plain Language Summary: The microbial methanogenesis and its mediated CH4 production potential in paddy soils differs based on various rice‐based cropping modes. However, the methanogenic pathways, microbial mechanisms of methane production, and their responses to key influencing factors under different cropping modes are still poorly documented. We investigated the differences in pathways of CH4 production and methanogenic communities and their responses to the corresponding different soil properties under three typical cropping modes in China, that is, Rice‐Wheat, Rice‐Fallow, and Double‐Rice rotation. Our results demonstrated significant differences in acetoclastic methanogenesis and dominant methanogenic communities in paddy soils under three cropping modes, which might be influenced by soil pH. This study provides a new perspective and further understanding of the methanogenic pathways and their associated microbial mechanisms under different cropping modes. Key Points: The CH4 production potential and methanogenic pathways and communities differ in soils under three cropping modesDifferences in soil properties (mainly soil pH) among three cropping modes mediated methanogenic communities and further regulated methanogenesis [ABSTRACT FROM AUTHOR]

Copyright of Agronomy Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: People living in the southeastern hilly areas of Bangladesh are primarily dependent on agriculture and face the problem of nutrient deficiency in soils. This research was conducted to assess the fertility status of paddy soils for better fertilizer management. Grid sampling (1 km × 1 km) was followed to collect soil samples, avoiding unusual spots (e.g., non‐agricultural land, settlements, hills, and forests). In total, 300 samples were collected (150 from each upazila) to assess the status of soil physical properties (soil texture) and chemical properties (pH, electrical conductivity, organic matter, and nutrients [nitrogen (N), phosphorus (P), potassium (K), sulfur (S), magnesium (Mg), boron (B), and zinc (Zn)]). Results: Results revealed that most of the soils were sandy to silt loam in texture. The soils were found to be strongly acidic with values of 4.79 and 4.73 in Ukhiya and Teknaf, respectively. Most of the soils were found to be nonsaline, except the paddy soils close to the sea and/or salt‐affected cultivated land. Soil organic matter in Ukhiya and Teknaf was low (1.47% and 1.43%, respectively). The soils in both upazilas were deficient in N, P, K, S, and Zn, but not in Mg in both upazilas and B in Teknaf. Conclusion: It is imperative that adequate amounts of nutrient provision are available to maintain soil health and produce a sustainable crop yield. We believe that these are the first digital soil maps developed at upazila level using ArcGIS software, which will be available for future reference. [ABSTRACT FROM AUTHOR]