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To control heavy metal pollution effectively, prevention of heavy metal accumulations in agricultural soils should be the priority rather than remediation of heavy metal contamination. In this research, papers which contained input and output fluxes of Cd, As, Cr, Hg, and Pb in topsoil (the plough layer) of agricultural lands in Hunan, Zhejiang, the Yangtze River Delta, Hainan, and China as a whole were explored. Fluxes of heavy metal species were recalculated, and future trends of pollution were predicted. Also, cases regarding the application of technologies to control the input and output of heavy metals were analyzed. Results indicated that atmospheric decomposition was the dominant input source of heavy metals in all study sites except Hainan. The relative contributions of fertilizers, irrigation water, and straw returning fluctuated greatly among different sites. Cd pollution in all sites was the most serious, followed by Cr and Pb. In Hunan, Cd has already exceeded the maximum limit value and needs to be controlled urgently. The input of heavy metals from irrigation water, fertilizers, and straw returning could be controlled by proposing more policies to manage their quality and application amounts. The amount of heavy metals absorbed by plants could be increased by cultivating crops with hyperaccumulators and high-biomass plants. [ABSTRACT FROM AUTHOR]

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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering 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.)

Satellite remote sensing has become an important means of forest fire monitoring because it has the advantages of wide coverage, few ground constraints and high dynamics. When utilizing satellites for forest fire hotspot monitoring, two types of ground hotspots, agricultural and other fire hotspots can be ruled out through ground object features. False forest fire hotspots within forested areas must be excluded for a more accurate distinction between forest fires and non-forest fires. This study utilizes spatio-temporal data along with time-series classification to excavate false forest fire hotspots exhibiting temporal characteristics within forested areas and construct a dataset of such false forest fire hotspots, thereby achieving a more realistic forest fire dataset. Taking Hunan Province as the research object, this study takes the satellite ground hotspots in the forests of Hunan Province as the suspected forest fire hotspot dataset and excludes the satellite ground hotspots in the forests such as fixed heat sources, periodic heat sources and recurring heat sources which are excavated. The validity of these methods and results was then analyzed. False forest fire hotspots, from satellite ground hotspots extracted from 2019 to 2023 Himawari-8/9 satellite images, closely resemble the official release of actual forest fires data and the accuracy rate in the actual forest fire monitoring is 95.12%. This validates that the method employed in this study can improve the accuracy of satellite-based forest fire monitoring. [ABSTRACT FROM AUTHOR]

Selenium (Se) is a micronutrient that has attracted significant attention, because the threshold for human health is low. During soil surveys in China, large areas of low-Se soil were found, and this condition may increase the probability of people suffering from Se deficiency. A multi-purpose regional geochemical survey conducted in the Lou Shao basin of Hunan Province found abundant Se-rich soils in Lianyuan City. However, as the primary grain-producing area in Hunan Province, the key factors affecting the spatial distribution of soil Se in the cultivated land of Lianyuan City remain to be elucidated. Therefore, based on the data of 5516 topsoil samples (0–20 cm) of cultivated land in Lianyuan City, we used geostatistics, correlation analysis, and a Geodetector to explore the effects of geological conditions (strata), soil types, soil properties, and topography on the distribution of Se in soil. The results showed that (1) in comparison to cultivated land in the Chinese mainland, Japan, Belgium, and Sweden, the cultivated land in Lianyuan City exhibits higher Se contents, with Se-sufficient and Se-rich areas accounting for 9.74% and 88.96% of the total area, respectively; (2) the distribution of high-Se soil was consistent with that in the Longtan Formation, Dalong Formation, and Daye Formation; (3) organic matter (OM) showed a positive correlation with Se, while both the elevation and slope were negatively correlated with Se; (4) stratum had the most significant effect on the spatial variation in soil Se, followed by OM. Lianyuan City is a typical Se-rich area, and the high level of Se in soil reduces the risk of local residents suffering with diseases caused by Se deficiency. The synergistic effect of stratum and OM is the key factor influencing Se enrichment in soils. Moreover, low-lying flat areas are more conducive to the accumulation of Se. This study will help farmers to identify suitable Se-rich cultivation areas in order to increase the Se content in crops, thereby providing a valuable basis for improvements in human health and the optimization of agricultural strategies. [ABSTRACT FROM AUTHOR]

Introduction: This study emphasizes the importance of agricultural efficiency for food security and income generation, especially among smallholder rice farmers in southern China. Limited access to essential agricultural services hinders productivity in this region. The study highlights the significant potential of agricultural socialized services (ASS) in improving the technical efficiency of smallholder rice production. Methods: To analyze the impact of ASS on technical efficiency in rice production, we focused on tillage, transplanting, crop protection, and harvest operations. We employed stochastic frontier analysis and collected data from smallholder farmers in Hunan, Jiangxi, and Zhejiang provinces. By estimating the technical efficiency of rice production, we aimed to assess the relationship between ASS and smallholder farmers' technical efficiency. Results and discussion: The results of our analysis revealed that ASS significantly enhance the technical efficiency of rice production among smallholder farmers by supporting agricultural practices such as transplanting, crop protection, and harvest operations. However, we found that the impact of ASS on tillage operations was not statistically significant. Participation in ASS enhances smallholders' access to modern production techniques, resources, and knowledge, leading to improved technical efficiency. These services also empower smallholder rice producers to adopt sustainable farming practices, access credit, financing, and market information, and promote collective action and cooperation, ultimately influencing technical efficiency. Conclusion: This study emphasizes the potential of ASS in improving the technical efficiency of smallholder rice production in southern China. Policymakers and agricultural organizations can use these insights to design interventions that promote efficient practices, enhance productivity, support livelihoods, and ensure food security in the region. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the Eighth International Conference on Ming History (ICMH) that was held in Shimen, Hunan Province, China from August 15, to August 20,1999. The event was attended by participants from East Asia. Speakers at the conference include Huang Qichen, Zhao Yi and Luan Chengxian. Among the topics discussed are trends in the studies of the political history of the Ming Dynasty since the founding of the People's Republic of China and the agricultural administration of the Ming Dynasty founder.

In the context of regional coordinated development, exploring the spatiotemporal evolution characteristics of agricultural eco-efficiency(AEE) in the middle reaches of the Yangtze River(MRYR) can provide decision support for the coordinated development of regional agriculture. This study proposes a theoretical hypothesis of AEE spatial convergence at the input-output level and uses the Super-SBM model, kernel density estimation, spatial autocorrelation and β-convergence model to calculate the spatiotemporal evolution and convergence characteristics of AEE in the MRYR from 2005 to 2020. The results show that (1) from 2005 to 2020, the AEE of the study area increased from 0.665 to 0.864, with the average efficiency of Hubei, Jiangxi, and Hunan reaching 0.794, 0.767, and 0.724, respectively; and (2)the overall spatial convergence rate of AEE is 0.045, and there is a phenomenon of "club convergence" between regions. The spatial convergence rates of Jiangxi, Hubei, and Hunan are 0.053, 0.063, and 0.048, respectively. The convergence rate slows down over time, (3) The farmers' living standards, per capita GDP, and technological level have promoted the improvement of AEE. Multiple planting indices and financial support for agriculture have not had a positive effect on the improvement of AEE. The region should strengthen the exchange and cooperation of agricultural production and pay attention to the pollution discharge problem of agricultural production. • This paper proposes a theoretical hypothesis of the spatial convergence of agricultural eco-efficiency (AEE). • From 2005 to 2020, the AEE in the middle reaches of the Yangtze River increased from 0.665 to 0.864. • The AEE convergence rates of Jiangxi, Hubei and Hunan were all higher than the overall region. • Farmers' living standards, per capita GDP and science and technology level have a positive effect on the improvement of AEE. [ABSTRACT FROM AUTHOR]

Abstract: Emergy theory has its unique advantage in the research of regional economic system''s ecological efficiency. Namely, it can integrate ecological system and social economic system into one body so as to conduct unified statistical measurement and analysis on the real value of natural environment and human kind''s production activities, and therefore overcoming the shortcoming of only focusing on economic analysis. Based on the reference of previous researchers’ research literatures , this paper utilizes the relevent economic, social and environment statistics of Hunan province''s Agro-ecological system for the year of 2008, and carries out the computation and data processing of the input and output emergy for this system. And in the meantime, the authors also have analyzed the current situation of the input-output structure , the system''s load capacity , and the system''s operation efficiency among with other problems. This paper intents to lay a solid foundation for the future further research on the sustainable development of Hunan province''s Agro-ecological system. [Copyright &y& Elsevier]

Echinochloa crusgalli (L.) Beauv. (barnyard grass) is considered a noxious weed worldwide, and is the most pernicious weed decreasing rice yields in China. Recently, E. crusgalli has evolved quinclorac resistance, making it among the most serious herbicide resistant weeds in China. The present study explored differences in germination and growth between quinclorac-resistant and -susceptible E. crusgalli collected in Hunan Province. The order of the seven E. crusgalli biotypes assessed, from high to low quinclorac-resistance, was: quinclorac-resistant, Chunhua, Hanshou, Shimen, Hekou, Dingcheng, and quinclorac-susceptible. With an increased in the level of quinclorac-resistance, the germination rate, length of young shoots and roots, and fresh weight of E. crusgalli were all decreased compared with that in more susceptible biotypes. However, there were no significant differences between quinclorac-resistant and susceptible E. crusgalli biotypes without polyethylene glycol 6000 treatment. Drought had a more obvious effect on glutathione S-transferases (GST) activity, determined by spectrophotometric method, in quinclorac-resistant E. crusgalli. Higher resistance level biotypes showed greater activity, and when treated with polyethylene glycol 6000 for 3 days, all E. crusgalli biotypes showed the highest GST activity. This study demonstrated that as the level of quinclorac-resistance increased, the rate of seed germination decreased, while the growth of young buds, young roots, and fresh weight decreased. Increased quinclorac-resistance may be related to the increased metabolic activity of GST in E. crusgalli. [ABSTRACT FROM AUTHOR]

Climate change will inevitably continue for the next few decades and will have an impact on climate-sensitive agricultural production, emphasizing the need to design effective adaptive strategies to cope with climate risk or take advantage of potential climatic benefits. In this study, the latest version of the Crop Environment Resource Synthesis-Rice (CERES-Rice) model was applied to assess the impacts of climate change and carbon dioxide (CO2) fertilization on rice yield, as well as the effectiveness of two popularly adopted adaptive measures in Hunan Province, the main rice-production location in China. The simulation spanned 30 years of baseline (1981-2010) as well as three future periods (2011-40, 2041-70, and 2071-99) with climate data generated by five general circulation models under the newly developed representative concentration pathway (RCP) 4.5 and 8.5 scenarios. The simulation results showed that, in comparison with average rice yield during the baseline (1981-2010), the ensemble-average yield of all cultivars during the 2020s, 2050s, and 2080s would decrease under both RCPs without CO2 fertilization effects. The ensemble-average yield reduction during the 2080s was alleviated under both RCPs if CO2 fertilization effects were accounted for. Adaptation simulations indicated that two adaptive measures (switching cultivars and changing planting dates) could mitigate the adverse effect to different extents. The intermodel variability under both RCPs was generally small. These findings may provide useful insight into the potential impacts of climate change on rice yield and effective adaptive measures to mitigate the adverse effect of future climate change in Hunan Province. [ABSTRACT FROM AUTHOR]