Maize stalk rot reduces grain yield and quality.Information about the genetics of resistance to maize stalk rot could help breeders design effective breeding strategies for the trait.Genomic prediction may be a more e...Maize stalk rot reduces grain yield and quality.Information about the genetics of resistance to maize stalk rot could help breeders design effective breeding strategies for the trait.Genomic prediction may be a more effective breeding strategy for stalk-rot resistance than marker-assisted selection.We performed a genome-wide association study(GWAS)and genomic prediction of resistance in testcross hybrids of 677 inbred lines from the Tuxpe?o and non-Tuxpe?o heterotic pools grown in three environments and genotyped with 200,681 single-nucleotide polymorphisms(SNPs).Eighteen SNPs associated with stalk rot shared genomic regions with gene families previously associated with plant biotic and abiotic responses.More favorable SNP haplotypes traced to tropical than to temperate progenitors of the inbred lines.Incorporating genotype-by-environment(G×E)interaction increased genomic prediction accuracy.展开更多
Tobacco is an essential cash crop in Zimbabwe and a strategic livelihood option for hundreds of thousands of rural households. However, the crop is linked to negative environmental, economic, and social impacts. The e...Tobacco is an essential cash crop in Zimbabwe and a strategic livelihood option for hundreds of thousands of rural households. However, the crop is linked to negative environmental, economic, and social impacts. The existing studies on tobacco cultivation in Zimbabwe present contradictory findings on the determinants and impacts of adoption, leaving unanswered questions about the crop’s sustainability impact in the country. This article investigates the determinants of smallholder farmers’ decisions to grow tobacco and the associated impacts of adoption. Random and purposive sampling were used to select 273 household surveys, including tobacco and non-tobacco smallholder farmers, and 56 expert interviews to answer the research questions. We employed regression models alongside expert interviews and document analysis to identify the determinants influencing the decision-making process of smallholder farmers in Zimbabwe regarding tobacco cultivation. Additionally, our investigation aimed to elucidate the perceived impacts associated with the adoption of this agricultural practice. The regression analysis indicated that the farmer’s age, education level, farming experience, family size, household income, and perceived high farm profitability are significant drivers of tobacco adoption. We also discovered divergent and convergent perceptions of the critical impacts of tobacco cultivation. The study highlights the need for proactive multi-stakeholder collaboration and sustainable financial arrangements to address the negative impacts of tobacco production. As the primary stakeholder responsible for regulating and promoting agricultural activities, the Zimbabwean government should provide meaningful financial support, increase access to credit, and ensure better market facilities for alternative crops to reduce the over-dependence on tobacco.展开更多
The morphological characteristics,pathogenicity and biological characteristics of the pathogen isolated from Maryland tobacco in Wufeng County of Hubei Province were studied in the laboratory. After cultivation on LB ...The morphological characteristics,pathogenicity and biological characteristics of the pathogen isolated from Maryland tobacco in Wufeng County of Hubei Province were studied in the laboratory. After cultivation on LB medium at 28 ℃ for 48 h,the colonies were light yellow,circular or amorphous,translucent,with smooth and slightly concaved surface and neat edge. Observation under electron microscope showed that the isolates was rod-shaped,decapsulated and gram-negative in the size of( 0. 5- 1. 0) μm×( 2. 2- 3. 0) μm,with 2- 8 flagella. After cultivation on CVP medium at 28 ℃ for 48 h,the colonies were sunken like a cup.The pathogen was able to grow in 5% NaCl medium at 37 ℃,and produced acid through glucose fermentation; it was facultative anaerobic,and could use citrates,but could not produce indole. It was preliminarily confirmed that the pathogen causing Wufeng Maryland tobacco hollow stalk was Pectobacterium carotovorum subsp. carotovorum.展开更多
Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,...Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,after which all experimental groups were digested at 35℃for 24 days.This pretreatment method efficiently broke the lignocellulose structure of the corn stalk.Different from the volatile fatty acids(VFAs)content,the pH and RS contents were relatively higher than those of the control during the pretreatment process.Furthermore,the highest methane production[185.03 mL•g-1 VS(volatile solid)]was achieved at 55.46%under 35℃in 6 h,which was higher than that of the normal corn stalk anaerobic digestion.The VFAs contents and pH increased compared to CK upon the addition of NaOH to adjust pH,and the RS content also increased slightly due to the degradability of lignocellulose during the whole-slurry anaerobic co-digestion.This work provided a potential method to sustainably treat wastewater and improve fermentation performance.展开更多
In this paper,we used Corn Stalk(CS)as a renewable and economical bio template to fabricate willemite scaffolds with the potential application in skull bone repair.CS was used as a sacrificial template to synthesize t...In this paper,we used Corn Stalk(CS)as a renewable and economical bio template to fabricate willemite scaffolds with the potential application in skull bone repair.CS was used as a sacrificial template to synthesize the scaffolds.Willemite scaffolds with the chemical formula of Zn2SiO4 and pore size in the range of 3 to 10µm could be successfully synthesized by soaking CS in the willemite solution for 24 h and sintering at 950°C for 5 h.The porosity of the samples was controlled by the soaking time(between 12 and 48 h)in the willemite solution from 5 to 35%,respectively.The properties of these scaffolds showed a good approximation with cranial bone tissue.In addition,cytotoxicity assays(MTT)were performed on Human Bone Marrow Stromal cells(HBMSc)and A172 human glioblastoma cell lines by direct and indirect culture methods to estimate their toxicity for bone and nerve cells,respectively.Alkaline Phosphatase(ALP)activity and DAPI/Phalloidin cell staining were also performed to investigate the efficiency of the scaffolds for bone tissue engineering applications.The results showed that the scaffolds had good biocompatibility with both HBMSC and A172 cells,noticeable improvement on ALP activity,and great apatite formation ability in Simulated Body Fluid(SBF).All the evidence ascertained that willemite scaffolds made by corn stalks could be a useful candidate for bone tissue engineering applications.展开更多
In Tanzania, tobacco is an important cash crop benefiting most farmers and stakeholders. However, the crop is characterized by a low yield per unit area. Several factors are responsible for the low yield and quality o...In Tanzania, tobacco is an important cash crop benefiting most farmers and stakeholders. However, the crop is characterized by a low yield per unit area. Several factors are responsible for the low yield and quality of tobacco, among which are damages caused by the insects and other pests. Major insect pests of tobacco are cutworms (Agrotis spp), budworms (Heliothis virescens (F.)), (Lepidoptera Noctuidae) and aphids (Myzus persicae, Aphis tabaci) (Homoptera: Aphididae). These pests adversely affect crop growth, yield and leaf quality. In order to reduce insect attack in tobacco, applying pesticides is a critical management practices. In Tanzania, various pesticides have been approved for use in controlling the pests. Currently, farmers are using Bamethrine 2.5 EC to control the pests. The Pesticide named Protector 700 WG with an active ingredient imidacloprid 700 g/kg is a new product introduced in Tanzania during the 2021/22 crop season. Research trials were conducted in three research sites, namely Ulowa-Kahama, Tumbi-Tabora and Mtanila-Chunya, on Protector 700 WG efficacy in different rates, 15 g, 20 g, and 25 g each dissolved in 20 litres of water. The Protector 700 Wg was compared with the standard pesticide (Bamethrin 2.5 EC). Absolute control was also inclusive where the plot had no application of pesticides. The results showed that Protector 700 WG at all rates outweigh the commonly used pesticide. The difference in the number of pests between Protector 700 WG and Bamethrin 2.5 EC was significantly at P < 0.005 also, in dry and green weights, the yield was significantly different at P < 0.005. However, when yield and number of insects were compared among the rates of protector, there was no significant difference. From these results, farmers are advised applying Protector 700 WG at the rate of 0.15 kg/ha by dissolving it in 200 litres of water.展开更多
Stalk strength increases resistance to stalk lodging,which causes maize(Zea mays L.)production losses worldwide.The genetic mechanisms regulating stalk strength remain unclear.In this study,three stalk strength-relate...Stalk strength increases resistance to stalk lodging,which causes maize(Zea mays L.)production losses worldwide.The genetic mechanisms regulating stalk strength remain unclear.In this study,three stalk strength-related traits(rind penetrometer resistance,stalk crushing strength,and stalk bending strength)and four plant architecture traits(plant height,ear height,stem diameter,stem length)were measured in three field trials.Substantial phenotypic variation was detected for these traits.A genome-wide association study(GWAS)was conducted using general and mixed linear models and 372,331 single-nucleotide polymorphisms(SNPs).A total of 94 quantitative trait loci including 241 SNPs were detected.By combining the GWAS data with public gene expression data,56 candidate genes within 50 kb of the significant SNPs were identified,including genes encoding flavonol synthase(GRMZM2G069298,ZmFLS2),nitrate reductase(GRMZM5G878558,ZmNR2),glucose-1-phosphate adenylyltransferase(GRMZM2G027955),and laccase(GRMZM2G447271).Resequencing GRMZM2G069298 and GRMZM5G878558 in all tested lines revealed respectively 47 and 2 variants associated with RPR.Comparison of the RPR of the zmnr2EMS mutant and the wild-type plant under high-and low-nitrogen conditions verified the GRMZM5G878558 function.These findings may be useful for clarifying the genetic basis of stalk strength.The identified candidate genes and variants may be useful for the genetic improvement of maize lodging resistance.展开更多
Objectives:Bangladesh stands as a prominent global consumer of tobacco,with alarming consequences on public health.The Global Adult Tobacco Survey reported that tobacco consumption claimed over 126000 lives in 2018,co...Objectives:Bangladesh stands as a prominent global consumer of tobacco,with alarming consequences on public health.The Global Adult Tobacco Survey reported that tobacco consumption claimed over 126000 lives in 2018,contributing to 13.5%of all deaths in the country.This study aims to explore the effectiveness of higher tax rates and tobacco use regulation as control mechanisms in mitigating tobacco consumption and health care cost burden,with a particular emphasis on its implications for public health.Methods:This study is based on the annual time series data over the period 2000-2020.The study employs the ordinary least square method to analyze the quantitative confirming the stationarity of data at level.This research uses different models to investigate individual effects and combined effects on both tobacco consumption and tobacco health care cost burden.Results:The study finds a negative relationship between tobacco tax rate and tobacco consumption.More specifically,the higher tax rate of tobacco(low(β=-0.3495),medium(β=-0.2319),high(β=-0.9033),premium(β=-0.7322),filtered(β=-0.2114),and non-filtered(β=-0.3452)categories)is significant to reduce tobacco use at 1%level of significance.The study finds similar results when it applied tobacco retail price instead of tobacco tax rate as the independent variable.Finally,the study investigates the impact on health care cost through tobacco consumption,tobacco control law,growth rate,export-import,and tobacco production.The results indicate that tobacco consumption,export-import,and tobacco production increases health care cost burden while tobacco use regulatory decreases it.By reducing tobacco consumption,higher taxes and tobacco use regulation contribute to alleviating the burden on the healthcare system,promoting healthier lifestyles,and aligning with global health objectives.Conclusions:Higher tax rate on tobacco products is necessary to increase the retail price so that tobacco users cannot consume tobacco.Specific tax and uniform tax base are needed so that tobacco users cannot switch to lower priced brands.Tobacco control laws need to revised and proper implementation should be ensured as well,to achieve the goal of tobacco free Bangladesh by 2040.Tobacco-related diseases,responsible for a significant proportion of deaths in the country,could witness a considerable decline with the successful implementation of higher tax rates and tobacco use regulation.This study provides insights that not only contribute to the economic discourse but also accentuate the broader public health benefits arising from effective tobacco taxation policies.展开更多
[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf ...[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf quality were investigated through plot experiments.[Results]The application of microbial fertilizers could improve the pH value of acidic soil,and composite microbial agent A showed the best application effect.The application of bio-organic fertilizer was beneficial to improving the contents of available phosphorus and available boron in acidic soil.The application of composite microbial agent A was beneficial to improving the contents of available phosphorus and available potassium in acidic soil,and could promote the growth of tobacco plants and improve the economic traits of flue-cured tobacco and the coordination of chemical components in tobacco leaves.The application of composite microbial agent B led to a downward trend in the content of available boron in acidic soil.The application of composite microbial agent B could promote the absorption of nutrients by tobacco plants,and improve their disease resistance and the quality of tobacco leaves.Due to the differences in functional microorganisms contained,the application effects of different microbial fertilizers in improving acidic tobacco-planting soil and improving tobacco leaf quality varied.Overall,the application of microbial fertilizers could increase soil pH,activate soil nutrients,promote tobacco growth,enhance disease resistance,increase tobacco output value,and improve tobacco quality.Microbial fertilizers have good application prospects in improving acidic soil and improving tobacco quality.[Conclusions]The application of microbial fertilizers to improve acidic tobacco-planting soil can ensure the normal growth and development of tobacco plants and the improvement of tobacco leaf quality,achieving high-quality and sustainable development of Zhaotong tobacco.展开更多
At present,there are still many difficulties in China s tobacco farmers,such as unreasonable age structure,generally low education level,lack of management ability,and low planting efficiency.It is necessary to cultiv...At present,there are still many difficulties in China s tobacco farmers,such as unreasonable age structure,generally low education level,lack of management ability,and low planting efficiency.It is necessary to cultivate new professional tobacco farmers.Based on the practical problems existing in the cultivation of professional tobacco farmers in China,such as vague screening criteria,lack of pertinence in training content,single training mode,immature evaluation system,insufficient follow-up support and unsystematic cultivation mechanism,this study put forward corresponding strategies and suggestions.展开更多
Green manure–crop rotation is a sustainable approach to protect crops against diseases and improve yield.However,the mechanism by which green manuring manipulates the crop-associated microbial community remains to be...Green manure–crop rotation is a sustainable approach to protect crops against diseases and improve yield.However,the mechanism by which green manuring manipulates the crop-associated microbial community remains to be elucidated.In this study,we explored the horizontal processes of bacterial communities in different compartments of the soil–root interface(bulk soil,rhizosphere soil,rhizoplane and endosphere)of tobacco by performing a field experiment including four rotation practices,namely,tobacco rotated with smooth vetch,ryegrass,radish,and winter fallow(without green manure).Results showed that the co-occurrence networks constructed by adjacent compartments of the soil–root interface with green manuring had more edges than without green manuring,indicating dramatic microbial interactions.Green manuring increased the dispersal-niche continuum index between bulk soil and other compartments,indicating that it facilitated the horizontal dispersal of microbes.For the different green manuring practices,the neutral community model explained 24.6–27.6%of detection frequency for bacteria,and at least one compartment under each practice had a normalized stochasticity ratio higher than the 50%boundary point,suggesting that the deterministic and stochastic processes jointly shaped the tobacco microbiome.In conclusion,green manuring generally facilitates bacterial community dispersal across different compartments and enhances potential interactions among adjacent compartments.This study provides empirical evidence for understanding the microbiome assembly under green manure–crop rotation.展开更多
Aluminum is an abundant metal in the earth’s crust that turns out to be toxic in acidic environments.Many plants are affected by the presence of aluminum at the whole plant level,at the organ level,and at the cellula...Aluminum is an abundant metal in the earth’s crust that turns out to be toxic in acidic environments.Many plants are affected by the presence of aluminum at the whole plant level,at the organ level,and at the cellular level.Tobacco as a cash crop(Nicotiana tabacum L.)is a widely cultivated plant worldwide and is also a good model organism for research.Although there are many articles on Al-phytotoxicity in the literature,reviews on a single species that are economically and scientifically important are limited.In this article,we not only provide the biology associated with tobacco Al-toxicity,but also some essential information regarding the effects of this metal on other plant species(even animals).This review provides information on aluminum localization and uptake process by different staining techniques,as well as the effects of its toxicity at different compartment levels and the physiological consequences derived from them.In addition,molecular studies in recent years have reported specific responses to Al toxicity,such as overexpression of various protective proteins.Besides,this review discusses data on various organelle-based responses,cell death,and other mechanisms,data on tobacco plants and other kingdoms relevant to these studies.展开更多
Glucosinolates(GSLs) and their hydrolytic products contribute to the quality traits of rapeseed flowering stalk tissues, such as taste, flavor and anticarcinogenic properties(Glucoraphanin). However, little is known a...Glucosinolates(GSLs) and their hydrolytic products contribute to the quality traits of rapeseed flowering stalk tissues, such as taste, flavor and anticarcinogenic properties(Glucoraphanin). However, little is known about the genetic mechanisms of GSL accumulation in rapeseed flowering stalks. In this study, the variation and genetic architecture of GSL metabolites in flowering stalk tissues were investigated for the first time among a panel of 107 accessions. All GSL compounds exhibited continuous and wide variations in the present population. Progoitrin,glucobrassicanapin and gluconapin were the most abundant GSL compounds. Five quantitative trait loci(QTL) significantly associated with three GSL compounds were identified by genome-wide association study. GRA_C04 was under selected during modern breeding, in which the ratio of lower GSL haplotype(HAP2) in the accessions bred before 1990(52.56%) was significantly lower than that after 1990(78.95%). Four candidate genes, BnaA01. SOT16, BnaA06. SOT17, Bna A06. MYB51a, and Bna A06. MYB51b, were identified in the GTL_A01 and 4OH_A06 regions.These findings provide new insights into GSL biosynthesis in flowering stalk tissues and facilitate quality improvement in rapeseed flowering stalks.展开更多
[Objectives]This study was conducted to find out the most suitable special formula fertilizer for flue-cured tobacco production in tobacco-growing areas of Zhaotong City,so as to provide a basis for scientific fertili...[Objectives]This study was conducted to find out the most suitable special formula fertilizer for flue-cured tobacco production in tobacco-growing areas of Zhaotong City,so as to provide a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.[Methods]Different formulas of special base fertilizer and special topdressing for tobacco were designed by optimizing and adjusting the application amounts and proportions of nitrogen,phosphorus,potassium and medium trace elements in fertilizer formulas,and the formulas of special base fertilizer and special topdressing for flue-cured tobacco production were selected through a field plot experiment.[Results]The combination of special base fertilizer and special topdressing was conducive to the early growth and rapid growth of tobacco plants under the condition of reduced fertilizer application,and the treatment using organic-inorganic compound fertilizer as the special base fertilizer was the most obvious,with an average growth period of two days increased.Compared with conventional fertilization,the yield,output value,average price,proportion of superior tobacco and proportion of medium and superior tobacco increased in the organic-inorganic compound fertilizer treatment,with the yield increasing by 5.96%,the output value increasing by 17.08%,the average price increasing by 10.49%,the proportion of superior tobacco increasing by 4.63%,and the proportion of medium and superior tobacco increasing by 2.44%.It was concluded from indexes including growth period,agronomic traits,disease incidence and economic traits,the fertilization mode of organic-inorganic compound fertilizer with the addition of trace elements(boron,magnesium and zinc)applied as the base fertilizer and nitrogen and potassium topdressing was most efficient and economic.[Conclusions]This study provides a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.展开更多
[Objectives]The paper was to explore the influence of unmanned aerial vehicle(UAV)low volume spray technology on the control effect of viruliferous thrips and tomato spotted wilt virus(TSWV)under different pesticide c...[Objectives]The paper was to explore the influence of unmanned aerial vehicle(UAV)low volume spray technology on the control effect of viruliferous thrips and tomato spotted wilt virus(TSWV)under different pesticide concentrations,and to explore the effective control nodes and methods of thrips and TSWV.[Methods]According to the occurrence characteristics of thrips and TSWV,the field control effects of 4 pesticides on thrips and TSWV were tested by UAV with the thrips number and disease index as indicators,following the principle of regional and periodic control trials.[Results]In the groups of UAV and artificial prevention and control,4 agents were used alternatively,including 1%emamectin benzoate ME,1.7%abamectin imidacloprid ME,5%emamectin benzoate WDG,and 30%pyriproxyfen dinotefuran SL.There was no significant difference in the control effect of thrips and TSWV among treatment 1(recommended dosage of UAV agent),treatment 2(reduction of recommended dosage of UAV agent by 25%)and treatment 4(recommended dosage of artificial control agent),and the control effects on thrips were more than 83.16%in the 3 treatments.The disease index of TSWV in the 3 treatments decreased from 8.64±1.37 in the blank control group to less than 3,which reached the prevention and control threshold.But treatment 3(reduction of recommended dosage of UAV agent by 50%)did not reach the prevention and control threshold.The disease index of TSWV in the blank control area increased with the increase of the number of live nymphs of thrips,and there was a significant positive correlation,with good fitness.[Conclusions]UAV has a significant impact on the control effect of thrips and TSWV under different pesticide concentrations.In the actual flight control application,it is recommended that the amount of the pesticides is about 3/4 and not less than 1/2 of that of the artificial application.The control area should be extended to 100 m of the ridge of the tobacco field,and UAV is used periodically to control thrips and TSWV for 5 times from pre-transplanting stage to pre-squaring stage of flue-cured tobacco.The control effect is significantly different from the traditional artificial application.展开更多
The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco...The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.展开更多
This paper is concerned with the cooperative target stalking for a multi-unmanned surface vehicle(multi-USV)system.Based on the multi-agent deep deterministic policy gradient(MADDPG)algorithm,a multi-USV target stalki...This paper is concerned with the cooperative target stalking for a multi-unmanned surface vehicle(multi-USV)system.Based on the multi-agent deep deterministic policy gradient(MADDPG)algorithm,a multi-USV target stalking(MUTS)algorithm is proposed.Firstly,a V-type probabilistic data extraction method is proposed for the first time to overcome shortcomings of the MADDPG algorithm.The advantages of the proposed method are twofold:1)it can reduce the amount of data and shorten training time;2)it can filter out more important data in the experience buffer for training.Secondly,in order to avoid the collisions of USVs during the stalking process,an action constraint method called Safe DDPG is introduced.Finally,the MUTS algorithm and some existing algorithms are compared in cooperative target stalking scenarios.In order to demonstrate the effectiveness of the proposed MUTS algorithm in stalking tasks,mission operating scenarios and reward functions are well designed in this paper.The proposed MUTS algorithm can help the multi-USV system avoid internal collisions during the mission execution.Moreover,compared with some existing algorithms,the newly proposed one can provide a higher convergence speed and a narrower convergence domain.展开更多
Taking the tobacco-growing area of Shashi Town,Liuyang City as the object,the number of registered,newly added and resigned tobacco farmers in each year,average age,number and proportion of tobacco farmers of differen...Taking the tobacco-growing area of Shashi Town,Liuyang City as the object,the number of registered,newly added and resigned tobacco farmers in each year,average age,number and proportion of tobacco farmers of different ages,number and proportion of tobacco farmers born in different eras,as well as planting scale and planting history of flue-cured tobacco in the last 10 years were analyzed statistically.The results showed that the number of tobacco farmers in Shashi Town showed a rapid decline trend from 2012 to 2018,while the average age continuously increased,and the average planting scale rose in a wave like way.From 2019 to 2021,the decline rate of the number of tobacco farmers slowed down,and the average planting scale continuously increased,while the aging of tobacco farmers accelerated.Meantime,the birth years of tobacco farmers were further concentrated in the 1960s,and they were mainly at the age of 50-59.The tobacco industry in Shashi Town of Liuyang City is facing the crisis of aging tobacco farmers and no successor of flue-cured tobacco planting,and it is predicted that the next 5-10 years will continue the change trend from 2019 to 2021.展开更多
This research aimed at testing the viability of using Sorghum Stalk Ash (SSA) as a partial replacement of lime in the stabilization of red clay soils for road subgrade construction. Red clay soils have been identified...This research aimed at testing the viability of using Sorghum Stalk Ash (SSA) as a partial replacement of lime in the stabilization of red clay soils for road subgrade construction. Red clay soils have been identified as highly expansive soils, which are affected by both climatic conditions and loading patterns. The consideration of both traffic loading patterns and climatic effects on these soils has been taken into account. A penetration test of 2.5 mm has been used on both pure red soils and stabilized soils at 10% and 15% partial replacement of lime with SSA and showed an improvement in the CBR of stabilized red clay soils up to 11.6%. Again, the PI of stabilized soils at 15% partial replacement of lime reduced up to 11.2%. The results obtained on both CBR and PI of these red clay soils are within the recommended values for the effective subgrade required for laying both permanent and flexible pavements. As a result, a recommendation of making use of SSA to lower the quantities of lime and its costs used in the stabilization of highly expansive soils have been tested through this research. However, further research on a more percentage partial replacement of lime to improve the PI of these soils to below 10% while keeping the CBR levels within the road construction regulations is welcomed.展开更多
基金funded by the CGIAR Research Program(CRP)on MAIZEthe USAID through the Accelerating Genetic Gains Supplemental Project(Amend.No.9 MTO 069033),and the One CGIAR Initiative on Accelerated Breeding+1 种基金funding from the governments of Australia,Belgium,Canada,China,France,India,Japan,the Republic of Korea,Mexico,the Netherlands,New Zealand,Norway,Sweden,Switzerland,the United Kingdom,the United States,and the World Banksupported by the China Scholarship Council。
文摘Maize stalk rot reduces grain yield and quality.Information about the genetics of resistance to maize stalk rot could help breeders design effective breeding strategies for the trait.Genomic prediction may be a more effective breeding strategy for stalk-rot resistance than marker-assisted selection.We performed a genome-wide association study(GWAS)and genomic prediction of resistance in testcross hybrids of 677 inbred lines from the Tuxpe?o and non-Tuxpe?o heterotic pools grown in three environments and genotyped with 200,681 single-nucleotide polymorphisms(SNPs).Eighteen SNPs associated with stalk rot shared genomic regions with gene families previously associated with plant biotic and abiotic responses.More favorable SNP haplotypes traced to tropical than to temperate progenitors of the inbred lines.Incorporating genotype-by-environment(G×E)interaction increased genomic prediction accuracy.
文摘Tobacco is an essential cash crop in Zimbabwe and a strategic livelihood option for hundreds of thousands of rural households. However, the crop is linked to negative environmental, economic, and social impacts. The existing studies on tobacco cultivation in Zimbabwe present contradictory findings on the determinants and impacts of adoption, leaving unanswered questions about the crop’s sustainability impact in the country. This article investigates the determinants of smallholder farmers’ decisions to grow tobacco and the associated impacts of adoption. Random and purposive sampling were used to select 273 household surveys, including tobacco and non-tobacco smallholder farmers, and 56 expert interviews to answer the research questions. We employed regression models alongside expert interviews and document analysis to identify the determinants influencing the decision-making process of smallholder farmers in Zimbabwe regarding tobacco cultivation. Additionally, our investigation aimed to elucidate the perceived impacts associated with the adoption of this agricultural practice. The regression analysis indicated that the farmer’s age, education level, farming experience, family size, household income, and perceived high farm profitability are significant drivers of tobacco adoption. We also discovered divergent and convergent perceptions of the critical impacts of tobacco cultivation. The study highlights the need for proactive multi-stakeholder collaboration and sustainable financial arrangements to address the negative impacts of tobacco production. As the primary stakeholder responsible for regulating and promoting agricultural activities, the Zimbabwean government should provide meaningful financial support, increase access to credit, and ensure better market facilities for alternative crops to reduce the over-dependence on tobacco.
基金Supported by Tobacco Research Project of Hubei Tobacco Company(2011-13)Scientific and Technological Project of Yichang City(A2011-201)
文摘The morphological characteristics,pathogenicity and biological characteristics of the pathogen isolated from Maryland tobacco in Wufeng County of Hubei Province were studied in the laboratory. After cultivation on LB medium at 28 ℃ for 48 h,the colonies were light yellow,circular or amorphous,translucent,with smooth and slightly concaved surface and neat edge. Observation under electron microscope showed that the isolates was rod-shaped,decapsulated and gram-negative in the size of( 0. 5- 1. 0) μm×( 2. 2- 3. 0) μm,with 2- 8 flagella. After cultivation on CVP medium at 28 ℃ for 48 h,the colonies were sunken like a cup.The pathogen was able to grow in 5% NaCl medium at 37 ℃,and produced acid through glucose fermentation; it was facultative anaerobic,and could use citrates,but could not produce indole. It was preliminarily confirmed that the pathogen causing Wufeng Maryland tobacco hollow stalk was Pectobacterium carotovorum subsp. carotovorum.
基金Supported by the Technological Project of Heilongjiang Province"the Open Competition Mechanism to Select the Best Candidates"(2022ZXJ05C01-03)。
文摘Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,after which all experimental groups were digested at 35℃for 24 days.This pretreatment method efficiently broke the lignocellulose structure of the corn stalk.Different from the volatile fatty acids(VFAs)content,the pH and RS contents were relatively higher than those of the control during the pretreatment process.Furthermore,the highest methane production[185.03 mL•g-1 VS(volatile solid)]was achieved at 55.46%under 35℃in 6 h,which was higher than that of the normal corn stalk anaerobic digestion.The VFAs contents and pH increased compared to CK upon the addition of NaOH to adjust pH,and the RS content also increased slightly due to the degradability of lignocellulose during the whole-slurry anaerobic co-digestion.This work provided a potential method to sustainably treat wastewater and improve fermentation performance.
文摘In this paper,we used Corn Stalk(CS)as a renewable and economical bio template to fabricate willemite scaffolds with the potential application in skull bone repair.CS was used as a sacrificial template to synthesize the scaffolds.Willemite scaffolds with the chemical formula of Zn2SiO4 and pore size in the range of 3 to 10µm could be successfully synthesized by soaking CS in the willemite solution for 24 h and sintering at 950°C for 5 h.The porosity of the samples was controlled by the soaking time(between 12 and 48 h)in the willemite solution from 5 to 35%,respectively.The properties of these scaffolds showed a good approximation with cranial bone tissue.In addition,cytotoxicity assays(MTT)were performed on Human Bone Marrow Stromal cells(HBMSc)and A172 human glioblastoma cell lines by direct and indirect culture methods to estimate their toxicity for bone and nerve cells,respectively.Alkaline Phosphatase(ALP)activity and DAPI/Phalloidin cell staining were also performed to investigate the efficiency of the scaffolds for bone tissue engineering applications.The results showed that the scaffolds had good biocompatibility with both HBMSC and A172 cells,noticeable improvement on ALP activity,and great apatite formation ability in Simulated Body Fluid(SBF).All the evidence ascertained that willemite scaffolds made by corn stalks could be a useful candidate for bone tissue engineering applications.
文摘In Tanzania, tobacco is an important cash crop benefiting most farmers and stakeholders. However, the crop is characterized by a low yield per unit area. Several factors are responsible for the low yield and quality of tobacco, among which are damages caused by the insects and other pests. Major insect pests of tobacco are cutworms (Agrotis spp), budworms (Heliothis virescens (F.)), (Lepidoptera Noctuidae) and aphids (Myzus persicae, Aphis tabaci) (Homoptera: Aphididae). These pests adversely affect crop growth, yield and leaf quality. In order to reduce insect attack in tobacco, applying pesticides is a critical management practices. In Tanzania, various pesticides have been approved for use in controlling the pests. Currently, farmers are using Bamethrine 2.5 EC to control the pests. The Pesticide named Protector 700 WG with an active ingredient imidacloprid 700 g/kg is a new product introduced in Tanzania during the 2021/22 crop season. Research trials were conducted in three research sites, namely Ulowa-Kahama, Tumbi-Tabora and Mtanila-Chunya, on Protector 700 WG efficacy in different rates, 15 g, 20 g, and 25 g each dissolved in 20 litres of water. The Protector 700 Wg was compared with the standard pesticide (Bamethrin 2.5 EC). Absolute control was also inclusive where the plot had no application of pesticides. The results showed that Protector 700 WG at all rates outweigh the commonly used pesticide. The difference in the number of pests between Protector 700 WG and Bamethrin 2.5 EC was significantly at P < 0.005 also, in dry and green weights, the yield was significantly different at P < 0.005. However, when yield and number of insects were compared among the rates of protector, there was no significant difference. From these results, farmers are advised applying Protector 700 WG at the rate of 0.15 kg/ha by dissolving it in 200 litres of water.
基金supported by the National Natural Science Foundation of China(31972487,31902101,32172009 and 32061143030)the Innovative Research Team of Universities in Jiangsu Province,the Science and Technology Development Plan Project of Henan Province(212102110152)+1 种基金the High-end Talent Project of Yangzhou Universitythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Stalk strength increases resistance to stalk lodging,which causes maize(Zea mays L.)production losses worldwide.The genetic mechanisms regulating stalk strength remain unclear.In this study,three stalk strength-related traits(rind penetrometer resistance,stalk crushing strength,and stalk bending strength)and four plant architecture traits(plant height,ear height,stem diameter,stem length)were measured in three field trials.Substantial phenotypic variation was detected for these traits.A genome-wide association study(GWAS)was conducted using general and mixed linear models and 372,331 single-nucleotide polymorphisms(SNPs).A total of 94 quantitative trait loci including 241 SNPs were detected.By combining the GWAS data with public gene expression data,56 candidate genes within 50 kb of the significant SNPs were identified,including genes encoding flavonol synthase(GRMZM2G069298,ZmFLS2),nitrate reductase(GRMZM5G878558,ZmNR2),glucose-1-phosphate adenylyltransferase(GRMZM2G027955),and laccase(GRMZM2G447271).Resequencing GRMZM2G069298 and GRMZM5G878558 in all tested lines revealed respectively 47 and 2 variants associated with RPR.Comparison of the RPR of the zmnr2EMS mutant and the wild-type plant under high-and low-nitrogen conditions verified the GRMZM5G878558 function.These findings may be useful for clarifying the genetic basis of stalk strength.The identified candidate genes and variants may be useful for the genetic improvement of maize lodging resistance.
文摘Objectives:Bangladesh stands as a prominent global consumer of tobacco,with alarming consequences on public health.The Global Adult Tobacco Survey reported that tobacco consumption claimed over 126000 lives in 2018,contributing to 13.5%of all deaths in the country.This study aims to explore the effectiveness of higher tax rates and tobacco use regulation as control mechanisms in mitigating tobacco consumption and health care cost burden,with a particular emphasis on its implications for public health.Methods:This study is based on the annual time series data over the period 2000-2020.The study employs the ordinary least square method to analyze the quantitative confirming the stationarity of data at level.This research uses different models to investigate individual effects and combined effects on both tobacco consumption and tobacco health care cost burden.Results:The study finds a negative relationship between tobacco tax rate and tobacco consumption.More specifically,the higher tax rate of tobacco(low(β=-0.3495),medium(β=-0.2319),high(β=-0.9033),premium(β=-0.7322),filtered(β=-0.2114),and non-filtered(β=-0.3452)categories)is significant to reduce tobacco use at 1%level of significance.The study finds similar results when it applied tobacco retail price instead of tobacco tax rate as the independent variable.Finally,the study investigates the impact on health care cost through tobacco consumption,tobacco control law,growth rate,export-import,and tobacco production.The results indicate that tobacco consumption,export-import,and tobacco production increases health care cost burden while tobacco use regulatory decreases it.By reducing tobacco consumption,higher taxes and tobacco use regulation contribute to alleviating the burden on the healthcare system,promoting healthier lifestyles,and aligning with global health objectives.Conclusions:Higher tax rate on tobacco products is necessary to increase the retail price so that tobacco users cannot consume tobacco.Specific tax and uniform tax base are needed so that tobacco users cannot switch to lower priced brands.Tobacco control laws need to revised and proper implementation should be ensured as well,to achieve the goal of tobacco free Bangladesh by 2040.Tobacco-related diseases,responsible for a significant proportion of deaths in the country,could witness a considerable decline with the successful implementation of higher tax rates and tobacco use regulation.This study provides insights that not only contribute to the economic discourse but also accentuate the broader public health benefits arising from effective tobacco taxation policies.
基金Supported by Science and Technology Program Major Project of Yunnan Branch,China National Tobacco Corporation(2020530000241022)。
文摘[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf quality were investigated through plot experiments.[Results]The application of microbial fertilizers could improve the pH value of acidic soil,and composite microbial agent A showed the best application effect.The application of bio-organic fertilizer was beneficial to improving the contents of available phosphorus and available boron in acidic soil.The application of composite microbial agent A was beneficial to improving the contents of available phosphorus and available potassium in acidic soil,and could promote the growth of tobacco plants and improve the economic traits of flue-cured tobacco and the coordination of chemical components in tobacco leaves.The application of composite microbial agent B led to a downward trend in the content of available boron in acidic soil.The application of composite microbial agent B could promote the absorption of nutrients by tobacco plants,and improve their disease resistance and the quality of tobacco leaves.Due to the differences in functional microorganisms contained,the application effects of different microbial fertilizers in improving acidic tobacco-planting soil and improving tobacco leaf quality varied.Overall,the application of microbial fertilizers could increase soil pH,activate soil nutrients,promote tobacco growth,enhance disease resistance,increase tobacco output value,and improve tobacco quality.Microbial fertilizers have good application prospects in improving acidic soil and improving tobacco quality.[Conclusions]The application of microbial fertilizers to improve acidic tobacco-planting soil can ensure the normal growth and development of tobacco plants and the improvement of tobacco leaf quality,achieving high-quality and sustainable development of Zhaotong tobacco.
基金Supported by Science and Technology Project of Guiyang Branch of Guizhou Tobacco Company Study on Cultivation of New Tobacco Management Entities in Guiyang Tobacco-growing Areas (2020-06).
文摘At present,there are still many difficulties in China s tobacco farmers,such as unreasonable age structure,generally low education level,lack of management ability,and low planting efficiency.It is necessary to cultivate new professional tobacco farmers.Based on the practical problems existing in the cultivation of professional tobacco farmers in China,such as vague screening criteria,lack of pertinence in training content,single training mode,immature evaluation system,insufficient follow-up support and unsystematic cultivation mechanism,this study put forward corresponding strategies and suggestions.
基金supported financially by the National Key Research and Development Program of China(2021YFD1700200)the China Agriculture Research System of MOF and MARA(CARS-22).
文摘Green manure–crop rotation is a sustainable approach to protect crops against diseases and improve yield.However,the mechanism by which green manuring manipulates the crop-associated microbial community remains to be elucidated.In this study,we explored the horizontal processes of bacterial communities in different compartments of the soil–root interface(bulk soil,rhizosphere soil,rhizoplane and endosphere)of tobacco by performing a field experiment including four rotation practices,namely,tobacco rotated with smooth vetch,ryegrass,radish,and winter fallow(without green manure).Results showed that the co-occurrence networks constructed by adjacent compartments of the soil–root interface with green manuring had more edges than without green manuring,indicating dramatic microbial interactions.Green manuring increased the dispersal-niche continuum index between bulk soil and other compartments,indicating that it facilitated the horizontal dispersal of microbes.For the different green manuring practices,the neutral community model explained 24.6–27.6%of detection frequency for bacteria,and at least one compartment under each practice had a normalized stochasticity ratio higher than the 50%boundary point,suggesting that the deterministic and stochastic processes jointly shaped the tobacco microbiome.In conclusion,green manuring generally facilitates bacterial community dispersal across different compartments and enhances potential interactions among adjacent compartments.This study provides empirical evidence for understanding the microbiome assembly under green manure–crop rotation.
文摘Aluminum is an abundant metal in the earth’s crust that turns out to be toxic in acidic environments.Many plants are affected by the presence of aluminum at the whole plant level,at the organ level,and at the cellular level.Tobacco as a cash crop(Nicotiana tabacum L.)is a widely cultivated plant worldwide and is also a good model organism for research.Although there are many articles on Al-phytotoxicity in the literature,reviews on a single species that are economically and scientifically important are limited.In this article,we not only provide the biology associated with tobacco Al-toxicity,but also some essential information regarding the effects of this metal on other plant species(even animals).This review provides information on aluminum localization and uptake process by different staining techniques,as well as the effects of its toxicity at different compartment levels and the physiological consequences derived from them.In addition,molecular studies in recent years have reported specific responses to Al toxicity,such as overexpression of various protective proteins.Besides,this review discusses data on various organelle-based responses,cell death,and other mechanisms,data on tobacco plants and other kingdoms relevant to these studies.
基金supported by the Key Research and Development project of Hubei Province (Grant Nos. 2020BBB083, 2021BBA097 and 2021BBA102)the National Key Research and Development Program of China (Grant No. 2016YFD0100202)。
文摘Glucosinolates(GSLs) and their hydrolytic products contribute to the quality traits of rapeseed flowering stalk tissues, such as taste, flavor and anticarcinogenic properties(Glucoraphanin). However, little is known about the genetic mechanisms of GSL accumulation in rapeseed flowering stalks. In this study, the variation and genetic architecture of GSL metabolites in flowering stalk tissues were investigated for the first time among a panel of 107 accessions. All GSL compounds exhibited continuous and wide variations in the present population. Progoitrin,glucobrassicanapin and gluconapin were the most abundant GSL compounds. Five quantitative trait loci(QTL) significantly associated with three GSL compounds were identified by genome-wide association study. GRA_C04 was under selected during modern breeding, in which the ratio of lower GSL haplotype(HAP2) in the accessions bred before 1990(52.56%) was significantly lower than that after 1990(78.95%). Four candidate genes, BnaA01. SOT16, BnaA06. SOT17, Bna A06. MYB51a, and Bna A06. MYB51b, were identified in the GTL_A01 and 4OH_A06 regions.These findings provide new insights into GSL biosynthesis in flowering stalk tissues and facilitate quality improvement in rapeseed flowering stalks.
基金Supported by Science and Technology Program of Yunnan Company of China National Tobacco Corporation(2020530000241022).
文摘[Objectives]This study was conducted to find out the most suitable special formula fertilizer for flue-cured tobacco production in tobacco-growing areas of Zhaotong City,so as to provide a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.[Methods]Different formulas of special base fertilizer and special topdressing for tobacco were designed by optimizing and adjusting the application amounts and proportions of nitrogen,phosphorus,potassium and medium trace elements in fertilizer formulas,and the formulas of special base fertilizer and special topdressing for flue-cured tobacco production were selected through a field plot experiment.[Results]The combination of special base fertilizer and special topdressing was conducive to the early growth and rapid growth of tobacco plants under the condition of reduced fertilizer application,and the treatment using organic-inorganic compound fertilizer as the special base fertilizer was the most obvious,with an average growth period of two days increased.Compared with conventional fertilization,the yield,output value,average price,proportion of superior tobacco and proportion of medium and superior tobacco increased in the organic-inorganic compound fertilizer treatment,with the yield increasing by 5.96%,the output value increasing by 17.08%,the average price increasing by 10.49%,the proportion of superior tobacco increasing by 4.63%,and the proportion of medium and superior tobacco increasing by 2.44%.It was concluded from indexes including growth period,agronomic traits,disease incidence and economic traits,the fertilization mode of organic-inorganic compound fertilizer with the addition of trace elements(boron,magnesium and zinc)applied as the base fertilizer and nitrogen and potassium topdressing was most efficient and economic.[Conclusions]This study provides a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.
文摘[Objectives]The paper was to explore the influence of unmanned aerial vehicle(UAV)low volume spray technology on the control effect of viruliferous thrips and tomato spotted wilt virus(TSWV)under different pesticide concentrations,and to explore the effective control nodes and methods of thrips and TSWV.[Methods]According to the occurrence characteristics of thrips and TSWV,the field control effects of 4 pesticides on thrips and TSWV were tested by UAV with the thrips number and disease index as indicators,following the principle of regional and periodic control trials.[Results]In the groups of UAV and artificial prevention and control,4 agents were used alternatively,including 1%emamectin benzoate ME,1.7%abamectin imidacloprid ME,5%emamectin benzoate WDG,and 30%pyriproxyfen dinotefuran SL.There was no significant difference in the control effect of thrips and TSWV among treatment 1(recommended dosage of UAV agent),treatment 2(reduction of recommended dosage of UAV agent by 25%)and treatment 4(recommended dosage of artificial control agent),and the control effects on thrips were more than 83.16%in the 3 treatments.The disease index of TSWV in the 3 treatments decreased from 8.64±1.37 in the blank control group to less than 3,which reached the prevention and control threshold.But treatment 3(reduction of recommended dosage of UAV agent by 50%)did not reach the prevention and control threshold.The disease index of TSWV in the blank control area increased with the increase of the number of live nymphs of thrips,and there was a significant positive correlation,with good fitness.[Conclusions]UAV has a significant impact on the control effect of thrips and TSWV under different pesticide concentrations.In the actual flight control application,it is recommended that the amount of the pesticides is about 3/4 and not less than 1/2 of that of the artificial application.The control area should be extended to 100 m of the ridge of the tobacco field,and UAV is used periodically to control thrips and TSWV for 5 times from pre-transplanting stage to pre-squaring stage of flue-cured tobacco.The control effect is significantly different from the traditional artificial application.
文摘The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.
基金supported in part by the National Natural Science Foundation of China(61873335,61833011,62173164)the Project of Science and Technology Commission of Shanghai Municipality,China(20ZR1420200,21SQBS01600,22JC1401400,19510750300,21190780300)the Natural Science Foundation of Jiangsu Province of China(BK20201451)。
文摘This paper is concerned with the cooperative target stalking for a multi-unmanned surface vehicle(multi-USV)system.Based on the multi-agent deep deterministic policy gradient(MADDPG)algorithm,a multi-USV target stalking(MUTS)algorithm is proposed.Firstly,a V-type probabilistic data extraction method is proposed for the first time to overcome shortcomings of the MADDPG algorithm.The advantages of the proposed method are twofold:1)it can reduce the amount of data and shorten training time;2)it can filter out more important data in the experience buffer for training.Secondly,in order to avoid the collisions of USVs during the stalking process,an action constraint method called Safe DDPG is introduced.Finally,the MUTS algorithm and some existing algorithms are compared in cooperative target stalking scenarios.In order to demonstrate the effectiveness of the proposed MUTS algorithm in stalking tasks,mission operating scenarios and reward functions are well designed in this paper.The proposed MUTS algorithm can help the multi-USV system avoid internal collisions during the mission execution.Moreover,compared with some existing algorithms,the newly proposed one can provide a higher convergence speed and a narrower convergence domain.
基金Supported by Science and Technology Project of Changsha Tobacco Company(20-22B02).
文摘Taking the tobacco-growing area of Shashi Town,Liuyang City as the object,the number of registered,newly added and resigned tobacco farmers in each year,average age,number and proportion of tobacco farmers of different ages,number and proportion of tobacco farmers born in different eras,as well as planting scale and planting history of flue-cured tobacco in the last 10 years were analyzed statistically.The results showed that the number of tobacco farmers in Shashi Town showed a rapid decline trend from 2012 to 2018,while the average age continuously increased,and the average planting scale rose in a wave like way.From 2019 to 2021,the decline rate of the number of tobacco farmers slowed down,and the average planting scale continuously increased,while the aging of tobacco farmers accelerated.Meantime,the birth years of tobacco farmers were further concentrated in the 1960s,and they were mainly at the age of 50-59.The tobacco industry in Shashi Town of Liuyang City is facing the crisis of aging tobacco farmers and no successor of flue-cured tobacco planting,and it is predicted that the next 5-10 years will continue the change trend from 2019 to 2021.
文摘This research aimed at testing the viability of using Sorghum Stalk Ash (SSA) as a partial replacement of lime in the stabilization of red clay soils for road subgrade construction. Red clay soils have been identified as highly expansive soils, which are affected by both climatic conditions and loading patterns. The consideration of both traffic loading patterns and climatic effects on these soils has been taken into account. A penetration test of 2.5 mm has been used on both pure red soils and stabilized soils at 10% and 15% partial replacement of lime with SSA and showed an improvement in the CBR of stabilized red clay soils up to 11.6%. Again, the PI of stabilized soils at 15% partial replacement of lime reduced up to 11.2%. The results obtained on both CBR and PI of these red clay soils are within the recommended values for the effective subgrade required for laying both permanent and flexible pavements. As a result, a recommendation of making use of SSA to lower the quantities of lime and its costs used in the stabilization of highly expansive soils have been tested through this research. However, further research on a more percentage partial replacement of lime to improve the PI of these soils to below 10% while keeping the CBR levels within the road construction regulations is welcomed.
