摘要：
<jats:p>Allelopathy has been considered a good explanation for the successful invasion of some invasive plants. However, the real latitudinal and longitudinal allelopathic effects on native species have rarely been documented since many exotics have spread widely. We conducted a Petri dish experiment to determine the latitudinal and longitudinal allelopathic patterns of an invasive alligator weed (<jats:italic>Alternanthera philoxeroides</jats:italic>) on a common crop (<jats:italic>Lactuca sativa</jats:italic>) in China, and find what determines the allelopathic intensity. The results showed that the allelopathic effects of <jats:italic>A</jats:italic>. <jats:italic>philoxeroides</jats:italic> increased with the latitude while decreased with the longitude. This indicated that <jats:italic>A</jats:italic>. <jats:italic>philoxeroides</jats:italic> used its allelopathy to gain competitive advantages more in its recent invaded communities than that in its early invaded ones as <jats:italic>A</jats:italic>. <jats:italic>philoxeroides</jats:italic> is expanding from southeast China to northwest China. Furthermore, we found that the allelopathic intensity of <jats:italic>A</jats:italic>. <jats:italic>philoxeroide</jats:italic> was negatively correlated to the leaf contents of soluble carbohydrate (SC), carbon (C) and nitrogen (N), but that was positively correlated to the leaf contents of soluble protein (SP), free amino acids (FAA), plant polyphenol (PP), phosphorus (P) and potassium (K). These results suggested that the allelopathic intensity of <jats:italic>A</jats:italic>. <jats:italic>philoxeroide</jats:italic> was more determined by the limited P and K nutrients as well as the intermediate allelochemicals (SP, FAA, PP) rather than the unlimited C, N and SC. Thus, we can speculate that the negative or positive effects of plant aqueous extracts are a function of not only the extract concentrations but also the trade-offs between inhibition and promotion of all components in the extracts. Then we could reduce the allelopathic effects of <jats:italic>A</jats:italic>. <jats:italic>philoxeroide</jats:italic> by controlling the component contents in the plant tissues, by fertilization or other managements, especially in the plant recent invaded communities.</jats:p>
作者机构：
[Núñez-Delgado A.] Dept. Soil Sci. and Agric. Chem., Univ. Santiago de Compostela, Engineering Polytech. School, Campus Univ. s/n, Lugo, 27002, Spain;[Varjani S.] Gujarat Pollution Control Board, Rameshwar Co. Op. H. Soc., 7, Near Aavkar Hall, Maninagar, Gujarat, Ahmedabad, 380 008, India;[Zhou Y.] College of Resources and Environment, Hunan Agricultural University, Hunan Province, Changsha, 410128, China;[López-Ramón V.] Fac. Experimental Sciences, University of Jaén, Jaén, E-23071, Spain;[Zhang Z.] William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, United States
作者机构：
[Hu, Ang] Hunan Agr Univ, Coll Resources & Environm, Changsha 410128, Peoples R China.;[Wang, Jianjun; Hu, Ang; Meng, Fanfan] Chinese Acad Sci, Nanjing Inst Geog & Limnol, State Key Lab Lake Sci & Environm, Nanjing 210008, Peoples R China.;[Wang, Jianjun; Meng, Fanfan] Univ Chinese Acad Sci, Beijing 100049, Peoples R China.;[Tanentzap, Andrew J.] Trent Univ, Sch Environm, Ecosyst & Global Change Grp, Peterborough, ON K9L 0G2, Canada.;[Tanentzap, Andrew J.] Univ Cambridge, Dept Plant Sci, Ecosyst & Global Change Grp, Cambridge CB2 3EA, England.
通讯机构：
[Jianjun Wang] S;State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academic of Sciences, Nanjing210008, China<&wdkj&>University of Chinese Academy of Sciences, Beijing100049, China
关键词：
dark matter;microbes;dissolved organic matter;global change
通讯机构：
[Bingyu Li] C;College of Resource & Environment, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China<&wdkj&>Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China
摘要：
Electrontransfer (ET) is the essence of most biogeochemical processesrelated to element cycling and contaminant attenuation, whereas ETbetween different minerals and the controlling mechanism remain elusive.Here, we used surface-associated Fe-(II) as a proxy to explore ET betweenreduced nontronite NAu-2 (rNAu-2) and Fe (hydr)-oxides in their coexistingsystems. Results showed that ET could occur from rNAu-2 to ferrihydritebut not to goethite, and the ET amount was determined by the numberof reactive sites and the reduction potential difference between rNAu-2and ferrihydrite. ET proceeded mainly through the mineral-mineralinterface, with a negligible contribution of dissolved Fe2+/Fe3+. Control experiments by adding K+ andincreasing salinity together with characterizations by X-ray diffraction,scanning electron microscopy/energy-dispersive spectrometry, and atomicforce microscopy suggested that ferrihydrite nanoparticles insertedthe interlayer space in rNAu-2 where structural Fe-(II) in rNAu-2 transferredelectrons mainly through the basal plane to ferrihydrite. This studyimplicates the occurrence of ET between different redox-active mineralsthrough the mineral-mineral interface. As minerals at differentreduction potentials often coexist in soils/sediments, the mineral-mineralET may play an important role in subsurface biogeochemical processes. Electron transfer from Fe-(II)-bearingclay minerals to Fe(hydr)-oxides proceeds mainly through the mineral-mineral interface,with the interior structural Fe-(II) and expandable interlayer spacein clay minerals serving as the major electron reservoir and reactionsite, respectively.
作者机构：
[Ke, Yong; Du, Jiali; Wang, Yunyan; Cao, Junjie; Min, Xiaobo; Zhang, Limin; Xu, Hui; Yu, Lin; Luo, Yongjian] Cent South Univ, Sch Met & Environm, Changsha 410083, Peoples R China.;[Ke, Yong; Wang, Yunyan; Min, Xiaobo] Chinese Natl Engn Res Ctr Control & Treatment Heav, Changsha 410083, Peoples R China.;[Ke, Yong; Wang, Yunyan; Min, Xiaobo] Water Pollut Control Technol Key Lab Hunan Prov, Changsha 410004, Peoples R China.;[Yao, Liwei] Hunan Agr Univ, Coll Resources & Environm, Changsha 410128, Peoples R China.
通讯机构：
[Liwei Yao] A;[Yunyan Wang] W;Authors to whom correspondence should be addressed.<&wdkj&>College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Water Pollution Control Technology Key Laboratory of Hunan Province, Changsha 410004, China<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>School of Metallurgy and Environment, Central South University, Changsha 410083, China<&wdkj&>Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
关键词：
sulfurization;precipitate-As(III);precipitate-As(V);elemental S;As 2 S 3
摘要：
<jats:p>Water and fertilizer managements are the most common practices to maximize crop yields, and their long-term impact on soil microbial communities has been extensively studied. However, the initial response of microbes to fertilization and soil moisture changes remains unclear. In this study, the immediate effects of nitrogen (N)-fertilizer application and moisture levels on microbial community of paddy soils were investigated through controlled incubation experiments. Amplicon sequencing results revealed that moisture had a stronger influence on the abundance and community composition of total soil bacteria, as well as ammonia oxidizing-archaea (AOA) and -bacteria (AOB). Conversely, fertilizer application noticeably reduced the connectivity and complexity of the total bacteria network, and increasing moisture slightly exacerbated these effects. NH<jats:sub>4</jats:sub><jats:sup>+</jats:sup>-N content emerged as a significant driving force for changes in the structure of the total bacteria and AOB communities, while NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup>-N content played more important role in driving shifts in AOA composition. These findings indicate that the initial responses of microbial communities, including abundance and composition, and network differ under water and fertilizer managements. By providing a snapshot of microbial community structure following short-term N-fertilizer and water treatments, this study contributes to a better understanding of how soil microbes respond to long-term agriculture managements.</jats:p>
通讯机构：
[Jie Zhao] K;Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China<&wdkj&>Guangxi Industrial Technology Research Institute for Karst Rocky Desertification Control, Nanning 530012, China<&wdkj&>Guangxi Key Laboratory of Karst Ecological Processes and Services, Huanjiang 547100, China<&wdkj&>Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China
关键词：
Chemical fertilization;Agricultural residue management;Soil micro-food web;Ecosystem multifunctionality;Economic benefit;Sustainable agriculture
作者机构：
[Yang, Jingjin; Wu, Genyi] Hunan Agr Univ, Coll Resources & Environm, Changsha 410128, Peoples R China.;[Jiang, Caihong] Hunan Res Acad Environm Sci, Changsha 410004, Peoples R China.;[Long, Wenqi] Hunan Ecol & Environm Monitoring Ctr, State Environm Protect Key Lab Monitoring Heavy Me, Changsha 410019, Peoples R China.;[Liu, Wangrong] Minist Ecol & Environm PRC, South China Inst Environm Sci, State Environm Protect Key Lab Environm Pollut Hlt, Guangzhou 510530, Peoples R China.
通讯机构：
[Genyi Wu] C;College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
In recent years, considerable attention has been paid to the volatile organic compounds (VOCs) that might lead to serious environmental problems, yet few studies relate to the insecticide application during agricultural process. As there appears to be a notable lack of research on the VOCs pollution of insecticides, we aimed to assess the occurrence of insecticide VOCs in the laboratory and during the agricultural process in China that have not been previously investigated. We discuss the estimation of VOCs emission potentials (EPs) and actual emissions (AEs) posed by insecticide applications. For this purpose, nine insecticide formulations were collected for testing and were analyzed via a thermogravimetric analyzer (TGA) and a pump-suction photoionization detection (PID) gas detector. The results showed that the EPs of nine insecticide samples ranged from 12.30% to 81.30%, with a median of 41.59% and a mean of 45.41%. The average actual emission ratio (AER) for the different formulations ranged from 48.76% to 72.12%. AER value was significantly positively correlated with temperature, but significantly negatively correlated with relative humidity and atmospheric pressure. The results of this study provide a technical reference for establishing the corresponding emission inventory and determining the total amount of pesticide VOCs.
摘要：
Expose of cadmium (Cd) leads to severe leaf chlorosis and reducing nutrient uptake. It is unclear how plants responded to Cd stress in the roots, and its relation to the leaf chlorosis. Our results showed Cd disturbed the homeostasis of multiple nutrient element at different levels. The most reduced elements were Mn, Fe, with 96 %, 89 % decline in the leaves, that caused leaf chlorosis. The plants actively downregulated the expression of metal transporters to reduce Cd uptake, but consequently reducing Fe and Mn uptake. Moreover, Cd stress promoted the formation of iron plaque and significantly reduced the exchangeable ions on root surface. Importantly, ethylene plays an essential role in regulating iron plaque formation and the existent forms of Cd. Blocking ethylene biosynthesis significantly increased exchangeable Cd on the root surface and decreased the percentage of iron oxides bound Cd, thus leading to increase of Cd in the shoots. Above all, our results revealed plants actively control the expression of metal transporter and the ethylene-dependent iron plaque formation to reduce Cd uptake, but sacrificed iron nutrition. The mechanism of sequester Cd on rhizosphere by ethylene in response to Cd stress may provide guidelines for the mitigation of Cd accumulation in rice via ethylene-dependent rhizosphere regulation.
作者机构：
[Guan, Chunyun; Zhang, Yin; Chen, Can; Huang, Huang; Xu, Ying] Hunan Agr Univ, Coll Agron, Changsha 410128, Peoples R China.;[Guan, Chunyun; Zhang, Yin; Chen, Can; Huang, Huang] Hunan Engn Res Ctr Rice Field Ecol Planting & Bree, Changsha 410128, Peoples R China.;[Li, Zhengyou] Fisheries Res Inst Guizhou Prov, Guiyang 550025, Peoples R China.;[Luo, Jun] Congjiang Agr & Rural Bur Guizhou Prov, Congjiang 557400, Peoples R China.;[Ren, Bo] Hunan Agr Univ, Coll Resources & Environm, Changsha 410128, Peoples R China.
通讯机构：
[Huang Huang] C;College of Agronomy, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Hunan Engineering Research Center of Rice Field Ecological Planting and Breeding, Changsha 410128, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
rice–fish–duck symbiosis system;globally important agricultural heritage system;value;technology;challenge;countermeasure
摘要：
<jats:p>The Chinese rice–fish–duck symbiosis system is one of the globally important agricultural heritage systems, with a history of nearly a thousand years. It embodies the wisdom of the Chinese ancestors and has huge comprehensive value, which has extremely important references for the sustainable development of agriculture. The technological core for the rice–fish–duck symbiosis system lies in the selection of rice, fish, and duck varieties and the coupling of agricultural operation time. In the process of modern agriculture, many varieties with high comprehensive benefits have also been applied to the rice–fish–duck system, and the rice–fish–duck model has been further developed. What is worrying is that the transfer of rural labor, the promotion of modern agricultural technology, the low degree of marketization and industrialization, the weakening of cultural awareness, and the change in climate have posed huge threats and challenges to the traditional Chinese rice–fish–duck system. The protection and development of the system are urgently needed. Therefore, we recommend delimiting active protection areas, establishing scientific research bases, improving relevant systems, developing rural tourism markets, and innovating farming technology, which also provide guidance for protecting and developing other agricultural cultural heritages.</jats:p>
摘要：
<jats:p>To produce a fast, accurate estimation for soil organic matter (SOM) by soil hyperspectral methods, we developed a novel intelligent inversion model based on multiscale fractal features combined with principal component analysis (PCA) of hyperspectral data. First, we calculated the local generalized Hurst exponent of the spectral reflectivity by multiscale multifractal detrended fluctuation analysis (MMA) while determining the sensitive spectral bands. PCA was employed to access the maximum principal component features of the sensitive bands used as the model input. Finally, two intelligent algorithms, random forest (RF), and a support vector machine (SVM), were utilized for establishing the SOM estimation model. The soil hyperspectral data possesses the typical nature of long-range correlation, presenting distinct fractal structures at different scales and fluctuations. The sensitive bands were from 359 nm to 405 nm, and were not impacted by window fitting size. The accuracy of the models of MMA-based sensitive bands is superior to that of the original bands. The PCA processing brings additional model performance improvement. The MMA-based models combined with RF is recommended for SOM estimation.</jats:p>
通讯机构：
[Lin Tang] C;College of Environmental Science and Engineering, Hunan University, Changsha 410082, China<&wdkj&>Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
期刊：
Science of The Total Environment,2023年858(Pt 1):159470 ISSN：0048-9697
通讯作者：
Wei Zhang
作者机构：
[Hu, Peilei; Xiao, Jun; Xiao, Lumei; Zhang, Wei; Xu, Lin; Ye, Yingying; Wang, Kelin; Xiao, Dan; Zhao, Jie] Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China;[Hu, Peilei; Xiao, Jun; Xiao, Lumei; Zhang, Wei; Xu, Lin; Ye, Yingying; Wang, Kelin; Xiao, Dan; Zhao, Jie] Huanjiang Observation and Research Station for Karst Ecosystems, Huanjiang, China;[Xu, Lin] College of Resources and Environment, Qingdao Agricultural University, Qingdao, China;[Zhang, Jiguang] Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China;[Hu, Peilei; Xiao, Jun; Wang, Kelin; Xiao, Dan; Zhao, Jie] Guangxi Industrial Technology Research Institute for Karst Rocky Desertification Control, Nanning, China
通讯机构：
[Wei Zhang] K;Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China<&wdkj&>Huanjiang Observation and Research Station for Karst Ecosystems, Huanjiang, China<&wdkj&>Guangxi Industrial Technology Research Institute for Karst Rocky Desertification Control, Nanning, China
关键词：
Bedrock exposure;Calcium;Initial pool size;Karst ecosystem;Soil carbon sequestration
摘要：
Vegetation restoration can increase soil carbon (C) content in karst regions characterized by highly exposed carbonate rocks; however, it remains unclear whether and how bedrock outcrops contribute to soil C-accumulation after vegetation restoration. We aimed to investigate the magnitude and mechanisms of bedrock outcrops on soil C-accumulation after vegetation restoration. Here, we selected 362 fixed locations to investigate changes in soil organic carbon (SOC) content and density before and after cropland restoration in a karst catchment with varying bedrock exposure ratios and initial soil C pools prior to restoration. Active vegetation restoration (i.e., cropland converted to forage grass, plantation forest, and a combination of grass and forest) and natural regeneration (cropland abandoned) were compared, with croplands maintained with no change as the control. Compared to croplands maintained with no change, SOC density significantly increased in the four vegetation restoration types. The SOC accumulation rate was higher for natural regeneration (39 g C m(-2) yr(-1)) than for the three active restoration strategies (18-27 g C m(-2) yr(-1)). SOC accumulation decreased with a higher initial pool size of soil C but increased with nitrogen accumulation and soil exchangeable calcium (Ca(2+)) concentration. Higher bedrock outcrops reduced soil volume but increased SOC content through their indirect effects on the initial pool size of soil C, external nitrogen inputs, and soil Ca(2+) concentration. This weakly promoted rather than inhibited SOC sequestration. Our findings highlight the effectiveness of various restoration strategies in promoting SOC accumulation in karst areas, as well as the need to take bedrock outcrops and initial soil C pools into consideration when modeling SOC dynamics and maximizing C sinks for vegetation restoration.
