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As one of the first Globally Important Agricultural Heritage Systems (GIAHS), the Qingtian rice-fish co-culture system serves as a global model for sustainable rice farming of paddy field carp (Cyprinus carpio). Based on the optimization of this traditional food system, this study evaluated the muscle nutrient quality of Qingtian paddy field carp (PF-carp) under three types of fertilizers, farming modes, and two types of stocking densities, aiming to provide a research reference for future aquaculture management of rice-fish farming. The results indicated that chicken manure as a basal fertilizer was more effective for crude fat enhancement in the muscles of PF-carp, while the addition of chemical fertilizer significantly reduced the contents of crude fat, saturated fatty acid, ash, and Ca2+ elements. Compared with chicken manure, the addition of rapeseed cake could increase the contents of delicious amino acid, essential amino acid, and essential amino acid index of PF-carp without affecting other nutritional indices. Among the modern, traditional rice-fish farming and pond farming modes, the atherogenicity index, thrombogenicity index, and hypocholesterolemic/hypercholesterolemic ratio of the fatty acids produced by the modern rice-fish farming mode were in the most desirable position. No significant differences were observed in all PF-carp nutritional indices at stocking densities of 0.45 inds/m2 and 0.91 inds/m2. Results emphasize the accumulation of crude fat is more advantageous in PF-carp under modern rice-fish farming mode, and the overall fatty acid ratio is more beneficial to human cardiovascular health. Rapeseed cake application could play an important role in improving the protein quality of PF-carp. [ABSTRACT FROM AUTHOR]

Potassium (K) is one of the essential nutrients that play a crucial role in rice fields; however, its availability, transport, and balance components can be influenced by alternating wetting and drying (AWD) irrigation practice. This study used the Hydrus-1D solute transport model to simulate K transport and balance components in AWD irrigated rice fields. Thirty lysimeter field experiment plots with three different irrigation treatments (No: no soil water stress, MS: mild soil water stress (400 cm), and SS: severe soil water stress (750 cm)) were used for rice cultivation. Daily measurements of soil matric potential head (SMPH) and ponding water depth (PWD) were recorded. Throughout the rice-growing season, leachate water samples from the surface (ponding water) and soil profiles were collected to measure K content. Using the lysimeter field experiment data, the Hydrus-1D model simulated K transport in the AWD rice field. The simulation results indicate that the K distribution predominantly occurred within the top puddled soil layer (0–20 cm) in AWD practice. This suggests that the recommended K fertilizer dose with a 4–5 cm PWD and SMPH of 400 cm optimizes K availability for rice while limiting K leaching loss. The Hydrus-1D model proves to be a valuable management tool, aiding in determining optimal K application rates and ponding water depths for AWD irrigation, ensuring sufficient K nutrients for rice, and controlling K loss for sustainable rice production. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Zinc deficiency is a significant global health concern, affecting around two billion people due to insufficient dietary intake. The extensive utilization of cereal-based meals with inadequate zinc content and limited bioavailability stands as the primary cause for this issue. Children who possess low levels of zinc experience stunted growth and developmental delays. They also have higher rates of morbidity from pneumonia, diarrhoea, and malaria. Inadequate zinc intake has been correlated with a heightened risk of mortality in children due to specific diseases. It is crucial to secure a satisfactory level of zinc in rice grains because of its indispensable function in various biochemical processes that are fundamental for the growth and advancement of plants. A deficiency in zinc can lead to reduced grain yield and nutritional value in rice. Recently, the utilization of registered biofertilizers and microbial technology is widely recognized in contemporary intensive farming practices. Some indigenous zinc-solubilizing bacterial strains discovered can increase rice yield and zinc content in grains. The objective of this study was to impact of a biofertilizer formula consisting of native zinc solubilizer strains on the growth, productivity, and zinc concentration in the grains of three rice varieties, namely Inpari IR Nutrizinc, Inpari 48, and Inpago 13 Fortiz. The study was conducted in a paddy field located in the Inceptisol of Subang Regency, West Java, during the year 2023. METHODS: The field trial was conducted to study the impact of a biofertilizer comprising a group of non-pathogenic zinc-solubilizing bacteria, including Enterobacter cloacae, Klebsiella pneumoniae, Serratia marcescens, Bacillus thuringiensis, and Enterobacter bugandensis on rice growth, yield, zinc levels, and uptake in grains. The rhizosphere soils were the origin of these bacteria, which were obtained using agar media containing zinc oxide as insoluble zinc compounds. Prior to this, the bacterial strains were evaluated for their capacity to dissolve zinc and generate the plant hormone indole-3-acetic acid. To gauge their zinc-solubilizing prowess, Pikovskaya agar media, supplemented with insoluble zinc oxide and calcium phosphate, respectively, were utilized. The presence of distinct clear areas surrounding the colonies demonstrated the effectiveness of the microbes in converting insoluble zinc and phosphorus into soluble forms. The concentration of the plant hormone indole-3-acetic acid was measured using the Salkowski reagent. The field trial was organized using a split-plot design with three replications. The application of the biofertilizer mixture as a seed treatment was carried out before the transplantation of the rice nursery. The seedlings were prepared individually for each rice variety, with a comparison made between those treated with the biofertilizer and those that were not. FINDINGS: The study found that the consortium of indigenous non-pathogenic zinc-solubilizing bacteria significantly increased the yield of rice varieties by about 5.6 percent and zinc content in grains by 16.3 percent. However, the application of zinc containing fertilizer treatments did not enhance the rice yield and zinc content in grains in this Inceptisol paddy soil. In terms of zinc content in grains, the rice variety Inpago 13 Fortiz exhibited a notable increase compared to the Inpari IR Nutrizinc variety, with levels of 40.3 milligrams per kilogram as opposed to 34.1 milligrams per kilogram. CONCLUSION: the utilization of a native combination of carefully chosen zinc-solubilizing bacterial strains could augment the productivity, zinc concentration, and absorption in rice grains of various varieties in a paddy field with Inceptisols soil type, characterized by a moderate to high overall zinc content and limited zinc accessibility. The addition of zinc containing fertilizer treatments did not enhance rice yield compared to the addition of other tratments or control. This is probably because of the medium-high level of the total zinc content of the soil, suggesting that the addition of Biofertizinc will reduce or delete the crop requirement for zinc fertilizer in Inceptisol paddy fields. This implies that the biofertilizer is ecologically sustainable as it eliminates the use of harmful chemicals, reduces the reliance on synthetic fertilizers, and lowers costs. [ABSTRACT FROM AUTHOR]

Abstract Soil microorganisms play pivotal roles in driving essential biogeochemical processes in terrestrial ecosystems, and they are sensitive to heavy metal pollution. However, our understanding of multiple environmental factors interaction in heavy metal polluted paddy fields to shape microbial community assembly remain limited. In the current study, we used 16S rRNA amplicon sequencing to characterize the microbial community composition in paddy soils collected from a typical industry town in Taihu region, eastern China. The results revealed that Cd and Pb were the major pollutant, and Proteobacteria, Acidobacteria and Chloroflexi were the dominate indigenous bacterial phyla. Linear regression and random forest analysis demonstrated that soil pH was the most important predictor of bacterial diversity. Mantel analysis showed that bacterial community structure was mainly driven by pH, CEC, silt, sand, AK, total Cd and DTPA-Cd. The constructed bacterial co-occurrence network, utilizing a random matrix theory-based approach, exhibited non-random with scale-free and modularity features. The major modules within the networks also showed significant correlations with soil pH. Overall, our study indicated that soil physiochemical properties made predominant contribution to bacterial community diversity, structure and their association in Cd/Pb polluted paddy fields. These findings expand our knowledge of the key environmental drivers and co-occurrence patterns of bacterial community in polluted paddy fields.

Agricultural by-products such as rice husks are very popular in Vietnam, which are often burned in the fields, causing an increase in dust smoke and greenhouse gas (GHG) emissions. To study the effects of different irrigation methods, quality of irrigation water and additive biochar from rice husk (BFRH) on leaching nitrate from paddy fields into shallow groundwater and CH4 emissions, we investigated a two-season experiment (2021-2023) under two irrigation methods: water-saving irrigation and flood irrigation with 120 kg N/ha. The results illustrated that seasonal CH4 emissions and leaching nitrate were affected by irrigation practices and significantly correlated with the quality of irrigation and the amount of BFRH added. To compare of control, the flood irrigation water increased the leaching of GHG and NO3- into shallow groundwater from 27.3-32.4% and 16.4 - 31.25%, respectively. Meanwhile, the saving water irrigation reduced CH4 and leaching of NO3- into shallow groundwater from 13.3-17.8% and 15.63 - 18.9%, respectively. Applying biochar with controlling fertilizer reduces CH4 and NO3- content in surface field water, contributing to the decreased leaching of NO3- into groundwater. Reducing 20% fertilizer rate of N (96 kg N/ha) with application biochar of 5% without a change in yield reduces NO3- content into shallow groundwater from 13.7 – 14.3%. We conclude that water-saving irrigation combined with biochar from rice husk incorporation simultaneously mitigates CH4 emissions, improves yield, and reduces leaching nitrate into groundwater, making it a suitable environment-friendly nitrogen management practice for sustainable farming in northern Vietnam.

Background: Selenium (Se) is essential for human health and is predominantly obtained from dietary sources, particularly rice in Hunan Province, a significant rice-producing region in southern China. Investigating the relationship between Se levels in paddy soil and rice grains, along with the associated influencing factors, is critical for enhancing Se-enriched food security. Results: Analysis of 128,992 samples collected between 2019 and 2022 revealed that the soil Se concentration in Hunan exceeded the global average, with rice grains showing promising potential for Se enrichment. Various analytical methods, including statistical analyses, co-occurrence networks, and correlation heatmaps, were utilized to scrutinize the extensive dataset. Additionally, partial least squares path analysis elucidated the interactive effects of influencing factors on soil Se concentration, rice grain Se concentration, and Se bioconcentration factor (BCF). Soil parent materials significantly affected soil Se concentration, rice grain Se concentration, and Se BCF (p < 0.01). Factors such as soil cation exchange capacity, soil organic matter, slope, and soil concentrations of Cu, Mn, and Zn demonstrated positive correlations with soil Se concentration. Similarly, these factors exhibited positive associations with rice grain Se concentration. Conversely, negative correlations were observed between certain factors and Se BCF. As a result, predictive models were developed for soil Se, rice grain Se concentration, and Se BCF. Conclusions: This study contributes valuable insights to inform policy-making for Se-enriched food production and to ensure regional nutritional equilibrium. Caution is recommended in areas with excessive Se levels to prevent potential poisoning risks. [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]

Soil microorganisms play pivotal roles in driving essential biogeochemical processes in terrestrial ecosystems, and they are sensitive to heavy metal pollution. However, our understanding of multiple environmental factors interaction in heavy metal polluted paddy fields to shape microbial community assembly remain limited. In the current study, we used 16S rRNA amplicon sequencing to characterize the microbial community composition in paddy soils collected from a typical industry town in Taihu region, eastern China. The results revealed that Cd and Pb were the major pollutant, and Proteobacteria, Acidobacteria and Chloroflexi were the dominate indigenous bacterial phyla. Linear regression and random forest analysis demonstrated that soil pH was the most important predictor of bacterial diversity. Mantel analysis showed that bacterial community structure was mainly driven by pH, CEC, silt, sand, AK, total Cd and DTPA-Cd. The constructed bacterial co-occurrence network, utilizing a random matrix theory-based approach, exhibited non-random with scale-free and modularity features. The major modules within the networks also showed significant correlations with soil pH. Overall, our study indicated that soil physiochemical properties made predominant contribution to bacterial community diversity, structure and their association in Cd/Pb polluted paddy fields. These findings expand our knowledge of the key environmental drivers and co-occurrence patterns of bacterial community in polluted paddy fields. [ABSTRACT FROM AUTHOR]

To determine the appropriate seeding rate for machine-transplanted hybrid rice, field experiments were conducted during 2022–2023 using the hybrid rice variety Huazhe You 210 as the material. Four seeding rate treatments were set up: 40 (T1), 60 (T2), 80 (T3) and 100 g tray-1(T4), to investigate the effects of seeding rate on the seedling quality, transplanting quality, yield formation, and economic benefits of high-quality indica hybrid rice seedlings. The results showed that with increasing seeding rate, the seedling base stem diameter and seedling plumpness of hybrid rice seedlings decreased, but the root entwining force gradually increased, leading to a deterioration in individual seedling quality but an improvement in collective characteristics. As the seeding rate increased, the missing hill rate during mechanical planting of hybrid rice significantly decreased, while the number of seedlings per hill and the damaged seedling rate showed an upward trend. The growth volume of tillers, tillering spikelet rate, and harvest index of hybrid rice in the field showed an overall downward trend with increasing seeding rate, while the accumulation of dry matter initially increased and then decreased. The yield and economic benefits of hybrid rice grains showed an initial increase followed by a decrease with increasing seeding rate, with the highest yield and economic benefits achieved with the T2 treatment. In conclusion, the appropriate seeding rate for machine-transplanted hybrid rice is T2 (60 g tray-1), which can maintain good seedling quality and improve transplanting quality, coordinate larger collective growth and appropriate harvest index, contributing to high yield and good economic benefits. [ABSTRACT FROM AUTHOR]

Recent research highlighted the need to include experimental estimates of tolerance limits to varying environmental conditions when investigating what factors limit species distributions. However, most niche approaches are only based on the statistical dependence between environmental and occurrence data. Here, we combined field data with survival experiments to assess the role of salinity as a limiting factor in the distribution of two species of exotic ostracods from the Iberian Peninsula. Vizcainocypria viator is a free-living species associated with rice fields and Ankylocythere sinuosa is a commensal of the red swamp crayfish (Procambarus clarkii). Experiments and field data indicate that the distribution of V. viator is limited by adult survival at low and high salinities (below electrical conductivity of 0.6 mS/cm and above 10 mS/cm). In the case of A. sinuosa, the analysis of field data shows that its prevalence is negatively affected by high salinity, whereas experiments indicate an optimal survival at high salinities (conductivity above 10.2 mS/cm), thus suggesting that high salinity may impact A. sinuosa distribution indirectly through affecting host traits (e.g. reduced activity). The habitat of close ancestors (marine versus non-marine respectively for A. sinuosa and V. viator) most likely explains the contrasting differences in salinity tolerance between both ostracod species. [ABSTRACT FROM AUTHOR]

Field ridges are commonly viewed as the stable semi-natural habitats for maintaining plant diversity in the agricultural landscape. The high plant diversity could further support higher animal diversity. But following the adoption of well-facilitated farmland construction measures in China, many field ridges have been disproportionately neglected or destroyed. Empirical studies delineating the relationships between plant and animal diversity in these field ridges in the paddy landscape remain scant, especially in China, which has the most rice production. A two-year field ridge evaluation was conducted in the Chengdu Plain area, covering 30 paddy landscapes. This investigation scrutinizes the shape attributes of field ridges, their plant diversity, and the associated animal α-diversity and community compositions, including spiders, carabids, birds, frogs, and rice planthoppers. In the results of Pearson's correlation analysis, a significant inconsistent correlation was observed between plant diversity and animal diversity. The analysis of community structure heterogeneity also revealed no correspondence for species composition between plant and animal communities (i.e., spiders, carabids, and birds), while the non-metric multidimensional scale analysis indicated a substantial difference in the species composition of spiders or plants even within the same field ridge between 2020 and 2021. We argue that the implementation of intensive management practices in paddy landscapes, such as machine ploughing and harvesting and herbicide spraying with drones, leads to a scarcity of stable animal and plant communities in field ridges. Therefore, besides retaining these field ridges in paddy landscapes, maintaining the long-term stable ridges by refraining from herbicide spraying or artificial weeding, as well as avoiding winter wheat cultivating in field ridges, will contribute to protecting biodiversity of field ridges as semi-natural habitats. [ABSTRACT FROM AUTHOR]

Rice is a major grain crop in numerous countries. In lowland areas, high iron levels in the soil severely hinder its cultivation. The current study explored high-yielding and Fe-toxicity-tolerant irrigated lowland rice (340 lines) among a population derived from a cross between Suakoko 8 and Bao Thai in Edozighi and Ibadan, Nigeria. In contrast to Ibadan, the soils in Edozighi contain a significant amount of iron. For the stated purpose, we carried out a two-year experiment using an alpha lattice design. The data showed significant differences between genotypes for the days to heading, plant height, number of tillers per plant, number of panicles per plant, panicle length, and grain yield. The results revealed that multiple characteristics had both direct and indirect effects on cultivated rice yields. There was a direct and positive influence on the number of days in the 50% heading period (0.31), a direct and negative effect on plant height (−0.94), a direct and positive effect on tiller and panicle numbers, and a direct but negative effect on panicle length (−0.56). The leaf bronzing score was adversely correlated with yield, panicle length, and plant height, while it was positively correlated with the number of panicles, tillers, and days to heading. The findings showed significant changes in yield and yield characteristics between genotypes. Grain yields ranged from 283 to 11,700 kg/ha in the absence of iron in the soil, contrary to 0 to 8230 kg/ha in soil with iron toxicity, with losses estimated between 6 and 94%, demonstrating the resulting disaster. In contrast to the elite parents and varieties used in this study, the ten top genotypes exhibited smaller losses in yield. The authors strongly recommend using these lines for further studies as donors or releasing them in farmer fields in Africa. [ABSTRACT FROM AUTHOR]

A significant crop pest, Mythimna loreyi, migrates annually to Korea and has been frequently observed in rice and corn fields. However, the phenology of this pest, particularly in relation to its ecological interactions and host crop seasons in Korea, remains poorly understood. This study aims to clarify the timing of the second generation of M. loreyi in Korea to enhance pest management strategies. To achieve this, we developed temperature-dependent models for developmental and ovipositional rates, studying these processes across five constant temperatures (15, 20, 25, 30, and 35°C). Our models, which showed a high correlation with observed data (r2 ≥ 0.93), include a theoretical approach that combines the developmental variation of immatures with the necessary degree-days for 50% egg laying and complete egg development. These predictions allow for the forecasting of the second generation's occurrence, with relatively small deviations (one to three days) observed at two different field sites. The insights from this study are critical for both understanding the ecology of M. loreyi and for informing practical management decisions, such as optimal placement of barriers to prevent immigration and strategies for controlling local populations. [ABSTRACT FROM AUTHOR]

AbstractThe research aims to investigate the Cadmium (Cd) contamination in rice fields within Sleman Regency due to its potential environmental and human health impact. The study was conducted from January to June 2023 and involved collecting soil samples from 23 irrigated rice fields within Sleman Regency with a grid sampling approach. Composite soil samples were created by blending five individual sub-samples from the cultivated layer (0-20 cm). The Cd levels in these samples were investigated using the Atomic Absorption Spectro-photometer (AAS) method. The findings revealed that all the sampled rice fields in Sleman Regency exceeded the critical limit of Cd concentration. The analysis of contamination factors (CF) and potential ecological risks (Er) indicated that the Cd contamination in Sleman Regency had reached a highly polluted level, carrying potential ecological risks. The extent of Cd contamination, primarily resulting from human activities (EF > 1), fell within the severe to extreme range (I-geo = 4-5). As a result, remediation measures are required to address the Cd contamination in Sleman Regency’s rice fields. These findings call for reducing the usage of chemical fertilizers, pesticides, and fungicides. Future studies should determine the possibility of cadmium accumulation in rice and its transfer from soil to rice. [ABSTRACT FROM AUTHOR]

AbstractIn this study, particulate matter (PM) variation has been analyzed to address the dearth of scientific research on air pollution in a coastal city from south India. Mean PM2.5 and PM10 concentrations were 61.6 ± 26.4 and 87.3 ± 35.4 μg/m3. The highest (lowest) seasonal concentration was observed during winter (monsoon). Increase in PM from September to February is attributed to low relative humidity, biomass burning in nearby paddy fields, and continental air mass from the east and north-easterly direction. The mean PM2.5/PM10 ratio was 0.71, with the seasonal ratio ranging between 0.64 (summer) and 0.76 (monsoon), indicating the dominance of anthropogenic PM fraction. PM exhibited typical characteristic of the urban region, i.e., a two-peak diurnal trend during all seasons except monsoon. PM10 (PM2.5) concentrations decreased by ∼7–24.2% (∼11–21%) on the weekends, with the highest reduction in winter seasons. Regarding correlation analysis among PM, CO, and ozone; a negative correlation between PM10 and O3 and a positive correlation between PM and CO was observed. Wind speed and PM10 showed a positive quadratic linear, whereas wind speed and PM2.5 showed a negative linear relationship. The primary sources of particulate matter in Kannur town are motor vehicle emissions, dust from construction work in surrounding zones, and nearby industrial units. [ABSTRACT FROM AUTHOR]

Arsenic (As) pollution in rice (Oryza sativa L.), a staple food for over 3.5 billion people, is a global problem. Mixed effects of Zn, Cu, and Si amendments on plant growth and yield, including in the presence of As pollution have been reported in previous studies. To better investigate the effectiveness of these amendments on rice growth, yield, and As accumulation, we conducted a rice greenhouse experiment with 11 treatments, including control pots with and without As contamination and pots with amendments of ZnO, CuO, and SiO2 nanoparticles (ZnO NPs, CuO NPs, and SiO2 NPs), their ionic counterparts (ZnSO4, CuSO4, and Na2SiO3), and bulk particles (ZnO BPs, CuO BPs, and SiO2 BPs). Compared with the background soil, the treatment of adding As decreased rice plant height, panicle number, and grain yield by 16.5%, 50%, and 85.7%, respectively, but significantly increased the As accumulation in milled rice grains by 3.2 times. Under As contamination, the application of Zn amendments increased rice grain yield by 4.6-7.3 times; among the three Zn amendments, ZnSO4 performed best by fully recovering grain yield to the background level and significantly reducing grain AsIII/total As ratio by 46.9%. Under As contamination, the application of Cu amendments increased grain yield by 3.8-5.6 times; all three Cu amendments significantly reduced grain AsIII/total As ratio by 20.2-65.6%. The results reveal that Zn and Cu amendments could promote rice yield and prevent As accumulation in rice grains under As contamination. Despite the observed reduction in As toxicity by the tested NPs, they do not offer more advantages over their ionic counterparts and bulk particles in promoting rice growth under As contamination. Future field research using a broader range of rice varieties, investigating various As concentrations, and encompassing diverse climate conditions will be necessary to validate our findings in achieving more extensive understanding of effective management of arsenic contaminated rice field. [ABSTRACT FROM AUTHOR]

A field survey was carried out in the farmer's field located at Chutsolie colony, Chumukedima, Nagaland, from July to November 2022 using light traps to study the incidence of lepidopteran pests occurring in rice, Oryza sativa L. The survey was conducted from the vegetative till harvesting stages of paddy. Fortnightly, observations of the lepidopteran pests were done and correlated with the weather parameters. During the survey, four lepidopteran pests, namely, Cnaphalocrocis medinalis (Guenee), Leucania loreyi (Duponchel), Melanitis leda (Linnaeus), and Scirpophaga incertulas (Walker) were observed. The highest peak population of C. medinalis (Guenee), M. leda (Linnaeus), and S. incertulas (Walker) were observed on the 37th standard mean week (SMW) (i.e., vegetative stage) whereas the highest population of L. loreyi on 41st SMW. (i.e., reproductive stage). The species M. leda constituted the highest population (75) and persisted in the field till the harvest, followed by S. incertulas (51), and C. medinalis (47). The species L. loreyi was the least in numbers (16). Among the species recorded, L. loreyi was the new record from Nagaland. [ABSTRACT FROM AUTHOR]

Simple Summary: It is well known that animal morphological traits are influenced by both genetic and environmental factors, but further research is needed to investigate the extent to which the environment influences morphological traits under the same genetic background. As one of the most widely distributed freshwater shrimp species in the world, the crayfish has a strong territorial and combative habit, so the influence of the aquaculture environment on its morphological development is more obvious. Meanwhile, under the same environment, different sexes of crayfish also showed corresponding morphological differences due to their reproductive functions. In this study, juvenile crayfish hatched from the same population were cultured in different growing environments, and the effects of environment and sex on their morphological characteristics were evaluated by mathematical models such as correlation analysis, pathway analysis, and gray correlation, so as to provide a basis for the artificial selection of crayfish in the later stage of development. In this study, juvenile crayfish hatched from the same population were cultured in different growing environments: pond (D1), paddy field (D2), and aquaculture barrel (D3), and fed for 60 days. Crayfishes were selected randomly, females and males, 50 tails each from six groups (D1-♀, D1-♂, D2-♀, D2-♂, D3-♀, D3-♂) to measure the following morphological traits: full length (X1), body length (X2), chelicerae length (X3), chelicerae weight (X4), cephalothorax length (X5), cephalothorax width (X6), cephalothorax height (X7), eye spacing (X8), caudal peduncle length (X9), and caudal peduncle weight (X10). We found that the coefficient of variation (CV) of X4 was the largest in each culture mode, and males (28.58%~38.67%) were larger than females (37.76%~66.74%). The CV of X4 of crayfish cultured in D1 and D2 was larger than that of D3. All traits except X8 were positively correlated with body weight (p < 0.05). After pathway analysis, we found that X4, X5, X7, and X10 were significantly correlated with the body weight of D1-♀; the equation was YD1-♀ = −29.803 + 1.249X4 + 0.505X5 + 0.701X7 + 1.483X10 (R2 = 0.947). However, X2, X4, and X6 were significantly correlated with the body weight of D1-♂; the equation was YD1-♂ = −40.881 + 0.39X2 + 0.845X4 + 1.142X6 (R2 = 0.927). In D2-♀, X1, X4, X5, and X10 were significantly correlated with body weight; the equation was YD2-♀ = −12.248 + 0.088X1 + 1.098X4 + 0.275X5 + 0.904X10 (R2 = 0.977). X4 and X5 played a major role in the body weight of D2-♂ with the equation: YD2-♂ = −24.871 + 1.177X4 + 0.902X5 (R2 = 0.973). X3 and X10 mainly contributed to the body weight of D3-♀ with the equation: YD3-♀ = −22.476 + 0.432X3 + 3.153X10 (R2 = 0.976). X1 and X4 mainly contributed to the body weight of D3-♂ with the equation: YD3-♂ = −34.434 + 0.363X1 + 0.669X4 (R2 = 0.918). Comparing the pathway analysis with the gray relation analysis, we could conclude that the traits most correlated with body weight in D1-♀ were X10 and X7; in D1-♂, X6; in D2-♀, X10, X1, and X5; in D2-♂, X5; in D3-♀, X10; and in D3-♂, X4 and X1. [ABSTRACT FROM AUTHOR]

Manipulative parasitoids manipulate the behaviour of their hosts in such a way as to benefit their own offspring. Paraponyx stagnalis Zeller is a leaf case worm caterpillar pest of rice and pupates in cases made out of cut leaf blades. These shelters are typically open-ended tubular cases. Its solitary primary endoparasitoid – Apanteles sp. – triggers changes in the way it sews the cases. The observed changes in the folded leaf shelter may serve various functions for the developing parasitoid, such as minimising the risk of hyperparasitism and predation, and enhancing structural stability. To obtain evidence to support these hypotheses, we (1) documented the morphotype of the cases/puparia constructed by unparasitised and parasitised P. stagnalis larval instars, (2) studied the overall rate of primary parasitism of P. stagnalis by Apanteles sp. and (3) studied the rate of hyperparasitism of primary parasitoids in 10 rice fields of south India. Unlike the unparasitised third-instar host larvae, the parasitised larvae sealed the open ends of the folded leaf shelter with silken threads, affixed the puparium to rice leaves and made small cases. The overall parasitism rate was about 40%. However, the hyperparasitism was between 0.6 and 1%. Though the primary parasitism by Apanteles sp. is considerably higher in all 10 fields, the meagre incidence of hyperparasitism strengthens our hypothesis that the modified puparium construction might be triggered by the primary parasitoid and beneficial for the offspring of the primary parasitoid. Our field observations suggest that future experimental studies can bring mechanical evidence for host manipulation by Apanteles sp. [ABSTRACT FROM AUTHOR]

• Accounting methods of agricultural methane are summarized. • Influencing factors of emission sources from agricultural sources were analyzed. • Mitigation strategies based on accounting and actual situation are proposed. Methane is one of the major greenhouse gases (GHGs) and agriculture is recognized as its primary emitter. Methane accounting is a prerequisite for developing effective agriculture mitigation strategies. In this review, methane accounting methods and research status for various agricultural emission source including rice fields, animal enteric fermentation and livestock and poultry manure management were overview, and the influencing factors of each emission source were analyzed and discussed. At the same time, it analyzes the different research efforts involving agricultural methane accounting and makes recommendations based on the actual situation. Finally, mitigation strategies based on accounting results and actual situation are proposed. This review aims to provide basic data and reference for agriculture-oriented countries and regions to actively participate in climate action and carry out effective methane emission mitigation. [Display omitted] [ABSTRACT FROM AUTHOR]

Because land is an entity that possesses both biophysical and geophysical features, it can be subdivided into several land covers and put to a variety of diverse uses. In this study, transformation matrices are generated using JAXA map data in order to conduct an analysis of the inter-land variability. In Hanoi, data collection took place over the course of four years (1990, 2000, 2010, and 2020). According to Vietnam's legislation, this timeframe is also equivalent to three phases of land use planning (LUP). According to the findings, the area of land used for urban development is expanding at a quick rate in this metropolitan region (by more than 13%), but the area used for rice production has experienced a significant decline (by approx. 23%). However, the pattern is not consistent from one planning period to the next. The research results are also linked to land use practices in Hanoi in the discussion section. This points to the compatibility with the current state of Vietnam's linear economic growth in recent times, as well as negative issues, such as land waste and forecasts of spatial changes in Hanoi. [ABSTRACT FROM AUTHOR]

Rice cropped policy has been constantly changing, affecting the value of irrigated land. This study aims to examine distribution patterns of irrigated land value from a new perspective of uncertainties in single- and double-cropped rice policies in China. The real options approach was employed to calculate irrigated land value under policy uncertainty, and Moran's index was applied to identify the spatial distribution characteristics of irrigated land value at the provincial level. The empirical results were as follows: significantly positive spatial correlations existed between the land value under two cropped rice policies. The northeast region of China had a low-value clustering effect based on geographical characteristics. In contrast, the southern provinces of China had a high-value clustering effect based on the criteria of administrative regions. This study considered policy uncertainty when evaluating the economic effect on irrigated land when revealing spatial correlation in land value. We provide a theoretical and empirical basis for the formulation of cropped rice policies. [ABSTRACT FROM AUTHOR]

Yellow stem borer, Scirpophaga incertulas Walker and leaf folder, Cnaphalocrocis medinalis Guenee are two dominant species among the rice insect pests and cause considerable economic losses in India. Various strategies have been applied for managing these pests and insecticides as chemical control factors are the first line of defense but it has become difficult to manage these pests due to the development of resistance. Therefore, identification of new molecules with selective properties, novel mode of action, low toxicity to non-targets and environmental safety is required with a view of sustainable pest management. In this direction, a new molecule i.e., flubendiamide 20 WG was evaluated under field conditions to access its bio-efficacy against yellow stem borer and leaf folder during rainy seasons of 2019 and 2020. The results of present investigations indicate that spray of flubendiamide 20 WG @ 25 g a.i. ha−1 first at tillering stage (30 days after transplanting) and second at panicle initiation stage (50 days after transplanting) or whenever the pests cross economic threshold level was found effective and best insecticidal treatment in mitigating the damage caused by yellow stem borer and leaf folder and consequently translated in higher grain yield during both the experimental seasons. Bio-efficacy of other insecticides viz. chlorpyriphos 20 EC @ 500 ml g a.i. ha−1, cartap hydrochloride 4G @ 750 g a.i. ha−1 and quinalphos 20 AF @ 200 ml a.i. ha−1 against yellow stem borer and leaf folder was significantly inferior to flubendiamide 20 WG @ 25 and 30 g a.i. ha−1 but superior over the control. No phytotoxicity symptoms were inflicted by foliar application of flubendiamide 20 WG (20, 25 and 30 g a.i. ha−1) on the rice crop during both the years of study. Phytotoxicity was recorded zero on scale of 0–10 indicating its 100% safety to the crop. Flubendiamide 20 WG was also found safe to different natural enemies viz. green mirid bug Cyrtorhinus lividipennis Reuter; seven spotted lady beetle, Coccinella septempunctata (Linnaeus) and spiders (Araneae: Aranidae) recorded in the rice field. Population of green mirid bug Cyrtorhinus lividipennis Reuter; seven spotted lady beetle, Coccinella septempunctata (Linnaeus) and spiders (Araneae: Aranidae) was recorded 1.74, 1.65 & 1.96/10 hills in the application of flubendiamide 20 WG @ 25 gm a.i. ha−1 as compared to 1.86, 1.70 & 2.12 in control, respectively during rainy season, 2020 indicating a non-significant difference among the treatment and control. Maximum grain yield (35.27 & 36.56 q ha−1) was observed in the treatments having the application of flubendiamide 20 WG @ 30 gm a.i. ha−1 during 2019 & 2020 crop seasons, respectively and it was at par with 25 g a.i. ha−1. The residues of flubendiamide 20 WG at 25 and 50 g a.i. ha−1 analyzed at harvest were below 0.01 mg kg−1 (limit of quantification) in paddy straw, grain and field soil. [ABSTRACT FROM AUTHOR]

Rainfall is one of the most important water sources for rice production in China. However, its temporal and spatial variability is leading to water shortages. The present study collected a long series of historical rainfall data from research sites during the rice growth period to analyze the characteristics of rainfall distribution and the correlation with rainfall utilization efficiency, aiming to investigate its impact on rice irrigation practices. It is found that the rainfall distribution varied greatly between the different locations and growth periods. The average rainfall of the whole growth period ranges from 135.5 mm to 694.5 mm. The rainfall curve exhibits a typical unimodal pattern with variations in the intensity, duration, and timing of peak precipitation across different growth periods. During the rice growth period, the cases in southern China are more prone to waterlogging for a high probability of continuous rainfall, and the cases in northern China are more prone to drought. The rainfall utilization efficiency of all cases exhibits a significant inter-year fluctuation range, negatively influenced by the rainfall amount and rainfall inhomogeneity. The efficiency in utilizing precipitation is diminished with greater and more uneven rainfall experienced during the growth period. These findings can provide a decision-making basis for optimizing rice irrigation strategies and enhancing rainfall utilization efficiency in diverse regions across China. [ABSTRACT FROM AUTHOR]

Biogas digestive effluent (BDE) is a nutrient-enriched source that can be utilized as an organic fertilizer for rice cultivation without synthetic fertilizer (SF) application. However, a primary concern is the stimulation of methane (CH4) emissions due to the enrichment of the labile organic carbon, a favorite substrate of methanogenic archaea. Methanotrophs potentially reduce greenhouse gas (GHG) emissions from rice fields owing to metabolizing CH4 as a carbon source and energy. We therefore examined the effect of the application of methanotroph-inoculated BDE to the rice cultivated paddy soil on GHG emissions and rice productivity under a pot experiment. Methanotrophs (Methylosinus sp. and Methylocystis sp.), isolated from the Vietnamese Mekong Delta's rice fields, were separately inoculated to the heated BDE, followed by a 5-day preincubation. Methanotroph-inoculated BDE was supplied to rice cultivation to substitute SF at 50% or 100% in terms of nitrogen amount. The results showed that the total CH4 emissions increased ~34% with the application of BDE. CH4 emissions were significantly reduced by ~17–21% and ~28–44% under the application of methanotroph-inoculated BDE at 100% and 50%, respectively. The reduction in CH4 was commensurate with the augmentation of pmoA transcript copy number under methanotroph-inoculated BDE. In addition, methanotroph-inoculated BDE application did not increase nitrous oxide (N2O) emissions and adversely affect rice growth and grain productivity. This study highlighted the BDE-recirculated feasibility for a lower CH4 emission rice production based on methanotrophs where high CH4-emitting fields were confirmed. [ABSTRACT FROM AUTHOR]

Controlled irrigation and drainage technology for rice is crucial water management that has been widely promoted in northeastern China. It is of great significance to clarify the response mechanism of the drainage volume and nitrogen loss load in the paddy field for realizing water saving, emission reduction, pollution control and high yield in rice-planting areas. In this study, we conducted field experiments and simulations on drainage volume and nitrogen loss load regulations of paddy fields in a cold black soil region under different hydrological years and irrigation and drainage modes. The key parameters for simulating drainage volume and nitrogen loss load in paddy fields using DRAINMOD-NII were determined by combining field experiments, data analysis, and numerical simulation. The results showed that the simulated drainage volume and nitrogen loss load showed a high coefficient of determination with the observed results, which were all above 0.83. The Nash–Sutcliffe efficiency coefficient ranged from 0.72 to 0.97 in model calibration and verification, indicating that the model effectively simulated drainage volume and nitrogen loss load in paddy fields under controlled irrigation and drainage in the cold black soil region. The paddy field drainage volume was not only influenced by rainfall frequency but also by the distribution of rainfall. Compared with traditional irrigation and drainage, the controlled irrigation and drainage significantly reduced the irrigation amount by 39.07% and increased rainwater utilization efficiency by 13.07%. It also reduced the drainage volume by 44.71% and NO3−-N and NH4+-N loss load by 59.38% and 44.96%. The controlled irrigation and drainage mode optimized natural rainfall resources and increased irrigation water productivity and rice yield by 97.85% and 16.88%, respectively. Controlled irrigation and drainage outperformed the traditional mode in different hydrological years, with more pronounced effects in dry years, which highlights its significant value in practical agricultural production. [ABSTRACT FROM AUTHOR]

An investigation into oomycete diversity in rice paddies of Fars Province in Iran led to the identification of two new Pythium sensu lato (s.l.) species as Globisporangium izadpanahii sp. nov. and Pythium banihashemianum sp. nov. The identification was based on morphological and physiological features as well as on the phylogenetic analysis of nuclear (ITS and βtub) and mitochondrial (cox1 and cox2) loci using Bayesian inference and Maximum Likelihood. The present paper formally describes these two new species and defines their phylogenetic relationships with other congeneric species. According to multiple gene genealogy analysis, G. izadpanahii sp. nov. was grouped with other species of Globisporangium (formerly, clade G of Pythium s.l.) and was closely related to both G. nagaii and the recently described G. coniferarum. The second species, designated P. banihashemianum sp. nov., was grouped with other species of Pythium sensu stricto (formerly, clade B of Pythium s.l.) and, according to the phylogenetic analysis, shared an ancestor with P. plurisporium. The production of globose hyphal swellings was a major characteristic of G. izadpanahii sp. nov., which did not produce vesicles and zoospores. In pathogenicity tests on rice seedlings, P. banihashemianum sp. nov. isolates were highly pathogenic and caused severe root and crown rot, while G. izadpanahii sp. nov. isolates were not pathogenic. [ABSTRACT FROM AUTHOR]

In Japan, rural areas are grappling with population decline and aging, leading to a shortage of labor for farmland maintenance. This has resulted in the abandonment of farmland or its conversion for solar photovoltaic (PV) use. However, this unplanned conversion raises concerns about agricultural productivity decline, landscape degradation, biodiversity loss, water resource maintenance, and disaster prevention. This study focuses on the Kushida watershed, examining (1) accurate farmland classification using remote sensing data, (2) the geographical distribution of farmland converted to PV systems from 2016 to 2021 and concentrated along the river, especially on north-facing slopes, (3) the highest conversion rates in wheat fields, followed by legume fields, tea fields, and paddy fields, and (4) no clear correlation between farmland conversions and changes in the number of farmers, but associations with farmland geography and solar radiation levels. These findings contribute to a nuanced understanding of sustainable rural development in Japan, emphasizing the importance of considering geographical factors in the conversion of farmland to PV. [ABSTRACT FROM AUTHOR]

Composing roughly 40 percent of the total Chinese population, village women were the linchpin of the thriving rural economy in late imperial China. This article addresses the question of women's work by reassessing the millennia-old "men till and women weave" trope, which asserted that farming (or the outer sphere it represented) was improper for women. It argues that, despite being marginalized or even eroticized in male-centered narratives, many women in Jiangnan China's economic and cultural center sweated in the fields and swiftly shifted their tasks for the family or market needs. Specifically, men dominated the more lucrative, more recognizable, and, in many cases, less arduous tasks in rice cultivation, while women significantly contributed to other tasks in the rice paddies and dominated cotton farming. Such a gender division of labor was affected less by biological factors or gender norms than by a combination of the physical property of crops (especially if the crop invites animal traction), the labor market, and a constantly evolving gendered narrative. In addition to self-conscious scholarly records of the gendered labor regime, much of the research relies on an original use of 891 criminal cases in the First Historical Archives (aka xingke tiben) to approach rural work patterns and the digital humanities methods to analyze and visualize the cases that serve as random samples of the crop regimes and everyday activities of rural men and women. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) is a staple food of more than half of the population of the world and provides food security and livelihoods for millions of population. Direct seeding of rice (DSR) refers to the process of direct sowing the seeds in the field rather than by transplanting seedlings from the nursery. Direct seeded rice is an age old practice and before the introduction of green revolution in India. Rainfed rice was often broadcasted into moist soil and crops were highly prone to weed competition resulted into low yield. Rice ecosystems and establishment methods determined the weed spectrum and degree of infestation in rice field (DSR). Weeds are considered as a major biological constraint in direct seeded rice. In direct seeded rice, weed management depend on weed flora, critical period of weed control, availability of water and method to be adopted. Integrated weed management (IWM) is essential to achieve the long term, sustainable and economic management of weeds in direct seeded rice. The literature regarding the direct seeded rice, critical period of crop weed competition, different types of weed flora and different methods for the effective and sustainable management of weeds in direct seeded rice are reviewed in this paper. [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]

Crop yield predictions are important for crop monitoring and agronomic management. The traditional methods for yield predictions are complicated and resource consuming. With the availability of affordable handheld imaging and computing devices, the image processing-based yield prediction methods are gaining popularity. In this work, RGB images of rice panicles are captured using DSLR camera with simple background and processed to determine the panicle area in terms of number of pixels. A machine learning-based model is developed to make predictions for rice yield. The model is trained to make predictions on unseen data. Various machine learning-based regression algorithms including decision tree, random forest, support vector machine, and convolution neural network are tested. The experiments are performed on a publically available dataset from China as well as on a self-acquired dataset in India. The results have shown that image processing and machine learning-based methods can make yield predictions satisfactorily as evident from the coefficient of determination ( R 2 ) that ranges 0.80–0.97 for different cultivars. The prediction error is determined in terms of root mean square error (RMSE) and mean absolute error (MAE). RMSE for different methods lies between 0.14 and 0.40, whereas MAE varies from 0.11 to 0.30. Among the tested algorithms, linear regression achieved the best precision with R 2 = 0.97, RMSE = 0.14, and MAE = 0.11. [ABSTRACT FROM AUTHOR]

Paddy (Oryza sativa) is one of the most consumed food grains in the world. The process from its sowing to consumption via harvesting, processing, storage and management require much effort and expertise. The grain quality of the product is heavily affected by the weather conditions, irrigation frequency, and many other factors. However, quality control is of immense importance, and thus, the evaluation of grain quality is necessary. Since it is necessary and arduous, we try to overcome the limitations and shortcomings of grain quality evaluation using image processing and machine learning (ML) techniques. Most existing methods are designed for rice grain quality assessment, noting that the key characteristics of paddy and rice are different. In addition, they have complex and expensive setups and utilize black-box ML models. To handle these issues, in this paper, we propose a reliable ML-based IoT paddy grain quality assessment system utilizing affordable sensors. It involves a specific data collection procedure followed by image processing with an ML-based model to predict the quality. Different explainable features are used for classifying the grain quality of paddy grain, like the shape, size, moisture, and maturity of the grain. The precision of the system was tested in real-world scenarios. To our knowledge, it is the first automated system to precisely provide an overall quality metric. The main feature of our system is its explainability in terms of utilized features and fuzzy rules, which increases the confidence and trustworthiness of the public toward its use. The grain variety used for experiments majorly belonged to the Indian Subcontinent, but it covered a significant variation in the shape and size of the grain. [ABSTRACT FROM AUTHOR]

In this research, parboiling was carried out at different times (5 and 15 min) on germinated paddy rice (GPR) from various basmati and non‐basmati varieties. The results showed that as the parboiling time increased from 5 to 15 min, Δ$\Delta $E, ash content, total dietary fiber, mineral content, cooking time, and textural properties increased while L*, lipid content, total starch, gruel solid loss, water absorption, oil absorption, foaming capacity, sugar profile, and total phenolic and flavonoid content decreased as compared to GPR. All pasting properties of GPR increased except breakdown as the parboiling time increased from 5 to 15 min. Parboiling altered the properties of GPR due to starch gelatinization. Total essential amino acid and gamma‐aminobutyric acid decreased as the parboiling time (5 to 15 min) increased. The germinated parboiled brown rice could create a highly nutritious alternative to regular brown rice as it offers improved texture and cooking qualities. [ABSTRACT FROM AUTHOR]

Methanol, the second most abundant volatile organic compound, primarily released from plants, is a major culprit disturbing atmospheric chemistry. Interestingly, ubiquitously found methanol-utilizing bacteria, play a vital role in mitigating atmospheric methanol effects. Despite being extensively characterized, the effect of nitrogen sources on the richness of methanol-utilizers in the bulk soil and rhizosphere is largely unknown. Therefore, the current study was planned to isolate, characterize and explore the richness of cultivable methylotrophs from the bulk soil and rhizosphere of a paddy field using media with varying nitrogen sources. Our data revealed that more genera of methylotrophs, including Methylobacterium, Ancylobacter, Achromobacter, Xanthobacter, Moraxella, and Klebsiella were enriched with the nitrate-based medium compared to only two genera, Hyphomicrobium and Methylobacterium, enriched with the ammonium-based medium. The richness of methylotrophic bacteria also differed substantially in the bulk soil as compared to the rhizosphere. Growth characterization revealed that majority of the newly isolated methanol-utilizing strains in this study exhibited better growth at 37 °C instead of 30 or 45 °C. Moreover, Hyphomicrobium sp. FSA2 was the only strain capable of utilizing methanol even at elevated temperature 45 °C, showing its adaptability to a wide range of temperatures. Differential carbon substrate utilization profiling revealed the facultative nature of all isolated methanol-utilizer strains with Xanthobacter sp. TS3, being an important methanol-utilizer capable of degrading toxic compounds such as acetone and ethylene glycol. Overall, our study suggests the role of nutrients and plant-microbial interaction in shaping the composition of methanol-utilizers in terrestrial environment. [ABSTRACT FROM AUTHOR]

In paddy soils, excessive application of N fertilizer often results in substantial N losses due to low N utilization efficiency. However, this condition can be mitigated by enhancing soil organic carbon content. Two-year field experiment was carried out at Mkula Irrigation Scheme in Kilombero Valley, Tanzania with the aim of investigating the impact of Azolla, rice straw incorporation and reduced levels of nitrogen input from NPKS-containing fertilizers on N use efficiency, soil chemical properties and rice grain yield. Assuming that this technology will introduce a novel perspective to the research, shedding light on alternative and potentially more sustainable methods for nitrogen management in paddy soils, it will be particularly relevant in sub-Saharan Africa, where the annual cost of chemical fertilizers is expected to continue rising. The treatments involved absolute control, half dose N (50 kg N ha-1), full dose N (100 kg N ha-1), and combination of these N doses with PKS, dry Azolla (3.41 ha-1) and rice straw (6.91 ha-1) through omission approach. The soil of the experimental area was sandy clay loam in texture, very strongly acid (pH 4.8), normal electrical conductivity (0.06 dS m-1), low amounts of recorded organic carbon (1.35%), total nitrogen (0.33%), 0.68 mg kg-1 available P, exchangeable potassium (0.15 cmol(+) kg-1), calcium (0.19 mg kg-1) and sodium percentage (3.75%), with very low cation exchange capacity (1.6 cmol(+) kg-1). The results showed that combination of Azolla, rice straw +100 kg N ha-1 + 30 kg P ha-1 + 30 kg K ha-1 + 20 kg S ha-1 resulted in higher rice grain yield, nitrogen uptake and agronomic efficiency of N. Azolla, being an effective biofertilizer, significantly contributes to nitrogen fixation and soil enrichment. Interestingly, this study demonstrates that co-application of Azolla, rice straw, and 50% reduced N is effective for achieving high rice yields, minimizing over-dependence on chemical N fertilizer, sustainable agricultural development, and environmental conservation. [ABSTRACT FROM AUTHOR]

Semi-natural grasslands on steep slopes often show high plant species diversity. These grasslands were traditionally maintained through mowing and/or grazing. The traditional management practices help to maintain species diversity, whereas land abandonment reduces diversity by increasing competition from dominant species and reducing seedling recruitment. The reintroduction of management can reverse species diversity declines, but suitable grassland restoration programs are scarce in Japan. To study the effect of short-term abandonment on seedling ecology, we monitored the vegetation of a Susogari grassland that had been abandoned for 3 years; the grassland occupies a steep slope (ca. 50°) on a hillside above paddy fields, and was traditionally mown. We monitored the vegetation before abandonment, in the 3rd year of abandonment, and in the 1st and 2nd years after restoration of mowing management. Emergence and survival of seedlings was monitored for 18 months after reintroduction of management. We monitored 1,183 seedlings of grassland species and non-target annuals in ten 1-m2 plots. After mowing was reintroduced, most grassland species reappeared or increased in the first and second years. Few seedlings of perennial plants and no seedlings of annuals flowered. An exotic species, Solidago altissima, had a lower survival rate (10%) than grassland species (>30%), and all but two grassland species survived over the 18-month period. Although vegetation composition was not fully recovered, our findings suggest that a steep slope acts as a strong filter that inhibits the establishment of non-target species while enhancing persistence of target grassland species. [ABSTRACT FROM AUTHOR]

Concerns about methane (CH4) emissions from rice, a staple sustaining over 3.5 billion people globally, are heightened due to its status as the second-largest contributor to greenhouse gases, driving climate change. Accurate quantification of CH4 emissions from rice fields is crucial for understanding gas concentrations. Leveraging technological advancements, we present a groundbreaking solution that integrates machine learning and remote sensing data, challenging traditional closed chamber methods. To achieve this, our methodology involves extensive data collection using drones equipped with a Micasense Altum camera and ground sensors, effectively reducing reliance on labor-intensive and costly field sampling. In this experimental project, our research delves into the intricate relationship between environmental variables, such as soil conditions and weather patterns, and CH4 emissions. We achieved remarkable results by utilizing unmanned aerial vehicles (UAV) and evaluating over 20 regression models, emphasizing an R2 value of 0.98 and 0.95 for the training and testing data, respectively. This outcome designates the random forest regressor as the most suitable model with superior predictive capabilities. Notably, phosphorus, GRVI median, and cumulative soil and water temperature emerged as the model's fittest variables for predicting these values. Our findings underscore an innovative, cost-effective, and efficient alternative for quantifying CH4 emissions, marking a significant advancement in the technology-driven approach to evaluating rice growth parameters and vegetation indices, providing valuable insights for advancing gas emissions studies in rice paddies. [ABSTRACT FROM AUTHOR]