Agricultural Population Research Articles

Sympatric populations of crop and wild carrots (Daucus carota ssp.) have distinct viromes, with shared core species more prevalent in farm-grown populations

Viral exchanges between crops and wild plants are important considerations in virus ecology and epidemiology but remain poorly understood. To investigate such exchanges, we compared the viromes of wild and farmed carrots (Daucus carota ssp.) growing near each other in France. Farm populations included cultivated varieties and off-type carrots (resembling wild ones) growing among them. This crop - wild relative pathosystem offers notable opportunities for virus exchange due to the hosts’ genetic closeness and geographic proximity. High-throughput sequencing found that viral taxonomic richness was greatest in wild carrots. However, hierarchical clustering and bipartite network analyses revealed that wild and farm carrot viromes differed in their seed-borne and vector-borne components. While ~50% of viral taxa were shared among carrot population types, others were uniquely associated with either wild or farm carrots. Individual-plant RT-PCR testing of 16 aphid-borne agents from the shared core virome found their prevalence was generally greatest in farm populations, with some geographic variability in virus pressure. The viromes of off-type and cultivated carrots were most similar, suggesting that proximity and/or management practices influence virome properties. For some aphid-borne viruses, similar isolates were found in wild and cultivated carrots, suggesting exchanges between them or with a shared source. However, isolates of other aphid-borne viruses clustered by carrot type, indicating barriers to viral fluxes, that might involve differential susceptibility of populations, vector preferences, or unidentified factors. To improve virus management, we need better understanding of how specific facilitators and barriers of viral exchange can be manipulated to reduce negative viral impacts.

Significant role of symbiotic bacteria in the blood digestion and reproduction of Dermanyssus gallinae mites

Abstract Endosymbiotic bacteria exert profound effects on the fitness of their arthropod hosts. Dermanyssus gallinae, the poultry red mite, is a blood-feeding ectoparasite that feeds solely on the blood of its avian hosts. A relatively comprehensive understanding of its microbial community structures across developmental stages based on 16S rRNA sequencing is available. Yet, their functional integration within the host's physiology remains elusive. This study endeavors to illuminate the role of symbiotic bacteria in the biology of D. gallinae mites. 16S rRNA amplicon sequencing and fluorescence in situ hybridization revealed a prominent midgut-confinement bacterial microbiota with considerable diversity, out of which Kocuria and Bartonella A acted as the predominant bacterial genera inhabiting D. gallinae. The relative abundance of Bartonella A exhibited rapid increments subsequent to blood-sucking, reflecting the bacteria's adaptation to grow in blood or indicating its pivotal role in the mites' post-engorgement life activities. Some of the isolated bacterial strains from D. gallinae display hemolytic activity on blood agar, which could potentially contribute to the blood digestion process in mites. To corroborate this in vivo, antibiotic-mediated clearance was exploited to generate dysbiosed cohorts of D. gallinae mites, lacking some of the key bacterial species. Phenotypic scoring of dysbiosed D. gallinae mites revealed that this cohort resulted in delayed blood digestion and diminished reproductive capacity. Whole genome sequencing revealed that Bartonella A, identified as a new species within the genus Bartonella, displays the characteristics of an obligate symbiont. These findings underscore the significance of microbiota in poultry red mites and suggest microbiota-targeted strategies for controlling mite populations in poultry farms.

Avoiding siloed approaches: Integrating psychological insights into sustainable farming.

This study enhances our understanding of the psychological factors influencing farmers' adoption of sustainable farming practices, specifically those related to achieving NetZero emissions. It achieves this by integrating various psychological theories with practical farming methods within the context of Behavioral-Adoption and Purpose-Driven contexts. The research consisted of two studies. Study 1 employed Exploratory Factor Analysis (EFA) to analyze responses from 438 UK farmers regarding their attitudes toward a series of Net Zero policy commitments, drawing on psychological theories including the Unified Theory of Acceptance and Use of Technology, the Theory of Planned Behavior, the Prototype Willingness Model, Implementation Intentions, Self-Determination Theory, Eudaimonia, and the Integrated Model of Health Literacy. The findings revealed a new Integrated Motivation Model for Sustainable Farming that comprises seven factors: Agricultural Commitment and Stewardship, Sustainable Farming Readiness and Confidence, Sustainable Incentive Engagement and Acceptance, Climate Adaptation Competence and Confidence, Net Zero Accountability and Reporting Commitment, Community Influence and Commitment in Sustainable Farming, and Innovation and Technological Competence. Study 2 validated these factors through the development of a 21-item Integrated Motivation Model for Sustainable Farming scale and use of Confirmatory Factor Analysis (CFA) to confirm the 7-factor structure using a subsample of 418 UK farmers from Study 1 and an additional 230 US farmers. Furthermore, Study 2 tested the concurrent validity of the new scale by demonstrating significant associations with reported sustainable farming behaviors. These findings underscore the complex interplay of motivational, cognitive, and social processes influencing sustainable farming practices. The integrated psychological model developed through this research provides parsimonious and valuable insights for policymakers to foster sustainable practices in farming effectively. The confirmation of this model across farming populations enhances its generalizability and potential to guide targeted interventions aimed at achieving behavioral change in pursuit of Net Zero targets in agriculture.

Mapping anthropogenic impacts on natural resources in the northeastern Sahara region: A case study on the past 26 years over the Ziban region (Algeria)

The objective of this research was to map and analyze anthropogenic impacts on natural resources in the Ziban region of Algeria using remote sensing imagery from 1995 to 2021. Medium-resolution satellite images from Landsat TM and OLI were utilized, with image processing techniques such as colorful compositions and supervised classification to map land cover. Seven land use and land cover (LULC) classes were identified, distinguishing human-derived categories (palm, agriculture, urban, and greenhouses) from natural surfaces (nebka, natural vegetation, and bare soil). The results indicated significant increases in human-driven elements like palm, urban areas, agriculture, greenhouses, and nebka, and notable decreases in natural components like vegetation and bare soil. Specifically, the rate of change (Tc) showed increases of 0.9% for palm, 1.14% for urban, 1.55% for agriculture, 1.91% for greenhouses, and 9.37% for nebka, and decreases of -3.68% for vegetation and -11.19% for bare soil. These findings highlight the impact of agricultural policies, population growth, and natural and human-induced conditions on natural resources. Palm areas remained largely unchanged due to state policies, whereas agriculture saw significant conversions to bare soil and palm. Vegetation declined substantially due to adverse climatic conditions and agricultural expansion. Nebka and urban areas had moderate to high conversion rates, and bare soil saw notable changes due to sand movement and urban/agricultural development. The study highlights the role of remote sensing and land cover analysis in managing natural resources sustainably, considering factors like agricultural policies and population growth. It emphasizes developing data-driven strategies for effective land use and management.

Adaptation of rice farmers to aging in Thailand

Abstract As one of the fastest-aging countries globally, Thailand faces unique challenges in its agricultural landscape due to the accelerated aging of its farming population. As rice is the most important crop, it is essential to understand the perceptions of farmers regarding the effects of aging on rice farming and how they adapt to aging. This research examined the adjustments that rice farmers had made in their practices over the past 5 years to cope with this demographic shift. The study utilized survey data collected from 300 rice farmers across two prominent rice-producing provinces in Thailand. The findings revealed that 32% of the surveyed rice farmers had adapted to the challenges posed by aging. The top two adaptive strategies allowed descendants to be more involved in rice farming activities and utilization of labor-saving machinery. To analyze the factors influencing the decision to adapt to aging, a binary probit model was employed. The results indicated that several factors played a positive and significant role in the rice farmers’ decisions. These included the farmer’s age, the size of agricultural land, access to irrigation, land ownership, the farmer’s perception of the impact of aging on rice farming, willingness to learn to use and embrace innovative technology for planting and harvesting, and a reduced number of farming activities performed through custom hiring services. Among these factors, irrigation, land ownership, and the farmer’s perception of the aging impact were found to have a strong influence on the farmer’s adaptation.

Study of spatial spillover effects and threshold characteristics of the influence of urbanization on grain green production efficiency in China under carbon constraints.

Food security is a basic guarantee for maintaining social stability, and improving green and healthy grain production is the way to promote food security. China is currently experiencing rapid urbanization that has an impact on grain production and security, with reduced arable land, environmental pollution, insufficient agricultural population, and inadequate resource allocation. How to deal with the relationship between urbanization and grain production becomes the key to solve this problem. Therefore, this study constructs an evaluation system of grain green production efficiency (GGPE) with non-expected output containing carbon emissions, and uses the super-efficient SBM model to measure the level of GGPE, and constructs a spatial econometric model to examine the spatial correlation and spillover effect of urbanization on GGPE; then constructs a panel threshold model to analyze the nonlinear threshold characteristics between urbanization and GGPE. It was found that (1) from 2000 to 2019, China's GGPE showed an overall upward trend, and the performance of GGPE varied among different provinces. (2) According to the results of the spatial econometric model, China's GGPE shows obvious spatial characteristics, and the level of urbanization not only directly affects regional GGPE but also can indirectly affect neighboring regions' GGPE through spatial spillover effects, and the indirect effects among regions are larger than the direct effects. (3) Spatial threshold effect results, there is a significant non-linear threshold characteristic of the impact of urbanization rate on GGPE. In terms of the influence effects of other variables, the influence of each variable on GGPE is roughly in the same direction as the influence under the spatial spillover effect, but the degree of influence is slightly different.

Depression, Anxiety, and Coping Strategies Among Farmworkers Exposed to Substance Use at Work

ABSTRACT Objective Migrant farmworkers are at an increased risk of experiencing high levels of stress, depression, anxiety, and problematic substance use. Farmworker behavioral health is a predominant concern for agricultural health and safety efforts. While substance use has been found to be a visible part of the work environment among farming populations, there is scarce information about how farmworkers who are exposed to substance use at work are impacted. Methods This exploratory assessment investigated the association between substance use exposure at work and migrant farmworkers’ (N = 58) symptoms of depression, anxiety, and coping strategies used. Univariate, bivariate, and regression analyses were conducted to examine data from a survey administered to migrant farmworkers in Southern California’s Riverside and Imperial Valley counties. Results Exposure to substance use at work was significantly associated with farmworkers reporting more severe symptoms of anxiety (p = .018). We also found that anxiety among farmworkers was significantly related to their experiences of sexual harassment (p = .026), being called names or insulted (p = .05), feeling unsafe (p = .005), having an increased work burden (p = .001), and caring for a colleague (p = .001). Furthermore, as exposure to substance use at work increased, farmworkers reported more severe symptoms of depression (F (1,45) = 7.90, p = .007) and anxiety (F (1,45) = 16.743, p = .001). To cope, the farmworkers in our sample reported using emotion-focused coping strategies most often. Conclusions Substance use exposure at work can affect migrant farmworker health and safety. Addressing and supporting the behavioral health of the entire farming community is warranted.

Greenhouse gas emissions from Chinese livestock sector can be decreased by one third in 2030 by the improvement in management

China is one of the largest contributors to global greenhouse gas (GHG) emissions, and the livestock sector is a major source of non-CO2 GHG emissions. Mitigation of GHG emissions from the livestock sector is beneficial to the sustainable development of the livestock sector in China. This study investigated the provincial level of GHG emissions from the livestock sector between 2000 and 2020 in China, to determine the driving factors affecting the provincial-level GHG emissions from the livestock sector, based on the logarithmic mean Divisia index (LMDI) model, which took into account of technological progress, livestock structure, economic factor, and agricultural population. Moreover, a gray model GM (1, 1) was used to predict livestock GHG emissions in each province until 2030 in China. The results showed that the GHG of Chinese livestock sector was decreased from 195.1 million tons (MT) CO2e in 2000 to 157.2 MT CO2e in 2020. Henan, Shandong, and Hebei provinces were the main contributors to the reduction in Chinese livestock GHG emissions, with their livestock GHG emissions reduced by 60.1%, 53.5% and 45.5%, respectively, in 2020 as compared to 2000. The reduction in GHG emissions from the Chinese livestock sector can be attributed to two main factors: technological progress and the shrinking of the agricultural laborers. In contrast, the agricultural economic development model with high input and high emissions showed a negative impact on GHG emission reduction in China’s livestock sector. Furthermore, the different livestock structure in each province led to different GHG reduction effects on the livestock sector. Under the gray model GM (1,1), the GHG emissions of the livestock sector will be reduced by 33.7% in 2030 as compared with 2020 in China, and the efficiency factor will account for 76.6% of the positive effect of GHG reduction in 2030. The eastern coastal region will be the main contributor to the reduction of GHG emissions from the Chinese livestock sector in 2030. Moreover, recommendations (such as upgrading livestock management methods and promoting carbon emission mitigation industries) should be proposed for the environmentally sustainable development of the livestock sector in the future.

“Agricultural to Non-agricultural” Ways and Chinese Labor Market Differentiation: Endowment Difference or Identity Discrimination?

Abstract Different methods of transforming rural migrants’ household registration can affect their integration into citizenship. This study assesses the impact of different rural-to- urban hukou conversion methods on labor market wages and job entry, utilizing empirical analysis with China General Social Survey (CGSS) data. Rural migrants transitioning to urban hukou are categorized as active or passive “agricultural to non-agricultural” groups. Wage disparities between these groups are analyzed using the Oaxaca-Blinder decomposition method, revealing that 50% of the wage gap remains unexplained by individual characteristics. Additionally, this paper explores factors contributing to wage and job entry differences using OLS regression analysis. Empirical findings indicate that discrimination significantly contributes to the wage and job entry gap between passive and active groups, with primary mechanisms including statistical bias, information acquisition differences, and identity challenges. These results underscore the inevitable transition of the agricultural population to urban areas in emerging nations’ development trajectory. However, challenges may arise during this transformation, particularly in China, where passive “agricultural to non-agricultural” individuals face discrimination. Addressing the rights and interests of this group is crucial for ensuring smooth urbanization in China and offers insights to improve urbanization efforts in developing nations.

Unveiling nitrate contamination and health risks: Insights from groundwater quality assessment and Monte Carlo simulation along the Southern Caspian Sea Coasts

Groundwater resources are at great risk of contamination due to increased industrial and agricultural activities, population growth and urban expansion. This study investigated factors controlling spatio-temporal variability in groundwater quality and nitrate concentration at the southern coast of Caspian Sea, Iran to provide public health risk assessment. Na-Cl (44.8%) and Ca-HCO3 (58.6%) types water were the dominant hydrogeochemical facies in dry and wet seasons, respectively. Most of the examined groundwater samples were found unfit for drinking but appropriate for agricultural irrigation. The chemistry of groundwater predominantly influenced by combination of local lithology and ion exchange in aquifer as well as seawater intrsuin. Nitrate concentration varied from 0.05 to 200 mg/L with a mean value of 33.1 mg/L in which 13.7% and 27.5% of samples showed concentration higher than WHO's recommended value in dry and wet seasons, respectively. The highest nitrate concentrations were observed at locations in proximity to human settlements including cities, villages as well as agricultural lands. The identified pollution hotspots confirm nitrate contributions from un-treated wastewater effluents and agricultural practices with minimum contribution from industrial activities. The result of Monte Carlo simulation revealed that children were at highest risk from drinking of groundwater containing nitrate. This study highlights the urgent need for action to address the growing threat to groundwater quality and public health posed by contamination from various sources in the southern coasts of Caspian Sea.

Metagenomics Insight into Veterinary and Zoonotic Pathogens Identified in Urban Wetlands of Los Lagos, Chile.

Wetlands are ecosystems that are essential to ecological balance and biodiversity; nevertheless, human activity is a constant threat to them. Excess nutrients are caused by intensive livestock and agricultural operations, pollution, and population growth, which in turn leads to uncontrolled microbiological development. This impairment in water quality can constitute a risk to animal, human, and environmental health. To thoroughly characterize the microbial communities, shotgun metagenomics was used to characterize the taxonomic and functional pattern of microorganisms that inhabit urban wetlands in the Los Lagos Region of Chile. The main objective was to identify microorganisms of veterinary relevance, assess their potential antibiotic resistance, and characterize the main virulence mechanism. As expected, a high diversity of microorganisms was identified, including bacteria described as animal or human pathogens, such as Pasteurella multocida, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Also, a diverse repertory of antimicrobial-resistant genes (ARGs) was detected in metagenomic assembled sequences and inside the sequence of mobile genetic elements, genes that confer mainly resistance to beta-lactams, consistent with the families of antibiotics most used in Chile. In addition, a diverse collection of virulence mechanisms was also identified. Given the significance of the relationship between environmental, animal, and human health-a concept known as One Health-there is a need to establish molecular surveillance programs that monitor the environmental biohazard elements using molecular tools. This work is the first report of the presence of these harmful biological elements in urban wetlands subjected to anthropogenic pressure, located in the south of Chile.

Spatiotemporal patterns and socioeconomic determinants of pulmonary tuberculosis in Dongguan city, China, during 2011–2020: an ecological study

ObjectivePulmonary tuberculosis (PTB) is a critical challenge worldwide, particularly in China. This study aimed to explore the spatiotemporal transmission patterns and socioeconomic factors of PTB in Dongguan city, China.Methods/designAn ecological...

Virtual play and real connections: unpacking the impact of rice farming simulation video games

This study investigates how the rice farming simulation video game Sakuna: Of Rice and Ruin affects interest in real-world agriculture and the inclination to start farming amidst Japan’s declining farming population. We surveyed 428 Japanese residents, including not only game players but also those who watch the game live or are merely aware of its existence. We also interviewed an individual who started rice farming after playing the game. The findings indicate that the game successfully stimulates greater interest in agriculture and somewhat motivates players to consider farming, more than just viewers or those who are aware of it. Moreover, individuals with real-life connections to agriculture, such as farming experience or professional connections, were optimistic about the transition from game to reality. The study suggests that rice farming simulation games can foster expectations of developing an interest in agriculture and potentially embarking on farming careers, demonstrating the game’s significant impact beyond entertainment.

The Byzantine Insular Countryside in the Early Middle Ages (ca. 600-ca.900): The Cases of Sicily, Cyprus, and Crete in (partial) Light of Environmental Archaeology

ABSTRACT This paper provides an overview of rural surveys and environmental archaeology studies on Sicily, Cyprus and Crete during the Byzantine Empire. It re-evaluates traditional interpretations of agricultural settlement patterns, ecosystems and populations from Late Antiquity to the early Middle Ages (late sixth to late ninth century). The prevailing narrative that these islands were devastated by Arab incursions, leading to widespread depopulation, economic collapse and abandonment of rural sites in favour of fortified hilltop settlements, is questioned. Instead, the study employs a comparative and interdisciplinary approach, combining environmental and climatic data with historical and archaeological evidence. This method offers a more nuanced understanding of how insular rural societies adapted to changing environmental and human conditions during the Byzantine Empire's transition from an economically unified region to a fragmented Medieval Mediterranean. The findings highlight the resilient nature of land use and rural settlement patterns amidst the transformation of the empire's political, military and administrative structures.

ОЦЕНКА ГЕНЕТИЧЕСКОЙ СТРУКТУРЫ СЕЛЬСКОХОЗЯЙСТВЕННЫХ ПОПУЛЯЦИЙ ОЛЕНЕЙ ЧУКОТСКОЙ И ЭВЕНСКОЙ ПОРОД КРАЙНЕГО СЕВЕРО-ВОСТОКА РОССИИ

The preservation of the allelofund and increasing the productivity of domestic reindeer in the Far North-East of Russia is currently an urgent problem against the background of a decrease in the number of livestock in agricultural populations. The research work was carried out during 2014-2023 in the reindeer herding farms of the Magadan region - Agricultural complex "Irbychan" and the Chukotka Autonomous Okrug - breeding farms of the Municipal Unitary Enterprise agricultural complex "Khatyrskoye", "Amguema". The total number of deer involved in the work was 17,356. The aim is to study the genetic structure of populations of Even and Chukchi breeds in domestic reindeer husbandry in the Far North-East of Russia. The plucked ears of deer served as the material for molecular genetic studies. The most common genotypes of the Even breed are those with loci in their composition №3 (240-330), №5 (350-430), №6 (440-520), №7 (520-570) and No. 9 (700-770). 99% of the Chukchi deer breed has a fragment with a length of 240-330 bp (locus No. 3). Loci No. 6 (440-520) and No. 7 (520-570) were found in 93% of individuals, locus No. 5 (350-430) – in 95%. The frequency of ISSR markers made it possible to determine the parameters of the general population for the Even and Chukchi rocks, which are characterized by polymorphism of all detected loci. Since individual DNA fragments were present in deer of all populations, it can be concluded that for the Even breed the spectrum consists of 3 amplicons No. 3, 5, 6, and for the Chukchi breed it consists of 4 amplicons: №3, №5, №6, №7 it is typical. The genetic variability of ISSR markers in populations indicates a significant similarity between them in most allelic frequencies, which confirms the common origin, economic and breeding use of Even and Chukchi deer. For the first time, long-term, long-term monitoring of the genetic characteristics of the populations of domestic reindeer of the Magadan region and Chukotka was carried out in a comparative aspect, which has urgent scientific and practical significance for further improvement of breeding work in reindeer husbandry.

The Need for Localized, Socio-economic Policy Measures for Controlling a Pandemic: An Empirical Study of COVID-19 in India

We examine the localized nature of COVID-19 pandemic spread in India. Through Gamma curve-fitting we observe that the infection patterns exhibit substantial variation across locations. Areas with larger male population and higher economic activity witness more cases. Economically-deprived districts experience higher mortality after controlling for the infections. Mobility in spatially contiguous locations is a significant determinant of new infections. Our study emphasizes the role of socioeconomic factors in explaining the variation across districts. The findings support the need for locally-specific policy, better medical infrastructure in socio-economically vulnerable localities and social-distancing measures in controlling the spread.

Fertilizer dependency: a new indicator for assessing the sustainability of agrosystems beyond nitrogen use efficiency

Cropping systems depend on external nitrogen (N) to produce food. However, we lack metrics to account for society’s fertilizer dependency, although excessive increases in N application damage human and environmental health. The objective of this study is to propose a novel indicator, N fertilizer dependency, calculated as the ratio between human-controllable external inputs and total N inputs. Nitrogen fertilizer dependency has a solid mathematical base being derived from closing the nitrogen use efficiency (NUE) equation. This study also tests the value of the N fertilizer dependency concept at the cropping system (plant-soil) scale and at different spatial scales, from field to country, as a complementary indicator to promote sustainable production. The field experiments conducted with grain cereals as a main crop showed that when replacing the barley precedent crop with a legume, N fertilizer dependency accounted for soil legacy and was reduced by 15% in fertilized treatments. In a farm population, N fertilizer dependency ranged from 47 to 95% and accounted for the relevance of biological fixation and irrigation water N inputs, adding pertinent information to performance indicators (i.e., NUE). At the country scale, N fertilizer dependency showed different temporal patterns, depending mainly on the relevance of biological atmospheric N fixation. Nitrogen fertilizer dependency of global cropping systems has risen to ≈83% in the last five decades, even though the N exchange among regions has increased. Nitrogen fertilizer dependency has great potential to monitor the achievements of efforts aiming to boost system autonomy, and within similar agricultural systems, it can be used to identify practices that lead to a reduction of fertilizer needs. In summary, N fertilizer dependency is a new indicator to evaluate the agroenvironmental sustainability of cropping systems across the scales and provides a complementary dimension to the traditional indicators such as NUE, N output, and N surplus.

BaTwa populations from Zambia retain ancestry of past hunter-gatherer groups

Sub-equatorial Africa is today inhabited predominantly by Bantu-speaking groups of Western African descent who brought agriculture to the Luangwa valley in eastern Zambia ~2000 years ago. Before their arrival the area was inhabited by hunter-gatherers, who in many cases were subsequently replaced, displaced or assimilated. In Zambia, we know little about the genetic affinities of these hunter-gatherers. We examine ancestry of two isolated communities in Zambia, known as BaTwa and possible descendants of recent hunter-gatherers. We genotype over two million genome-wide SNPs from two BaTwa populations (total of 80 individuals) and from three comparative farming populations to: (i) determine if the BaTwa carry genetic links to past hunter-gatherer-groups, and (ii) characterise the genetic affinities of past Zambian hunter-gatherer-groups. The BaTwa populations do harbour a hunter-gatherer-like genetic ancestry and Western African ancestry. The hunter-gatherer component is a unique local signature, intermediate between current-day Khoe-San ancestry from southern Africa and central African rainforest hunter-gatherer ancestry.

Why do aging households in agriculture prefer land abandonment to transfer? Evidence from hill plots in Sichuan, China

AbstractIncreased aging of the agricultural population may lead to a reconfiguration of land elements, but existing studies have not analyzed this on a plot level. China's vast hilly and mountainous regions will have a more serious impact on agricultural aging, but this context has still not received enough attention. Based on primary data from 2602 plots and 1080 farm households in the hilly areas of Sichuan, using human capital theory and instrumental variables approach, it is found that aging in agriculture will promote the abandonment of plots in the hilly areas, especially those that are remote, small in size and poor condition. Aging in agriculture will inhibit the out‐migration of plots in the hilly areas, and aging increases the abandonment of plots. In addition, this paper finds that the imperfect development of the land transfer market in hilly areas and the strong farmers' land endowment effect are the main reasons limiting land transfer. However, the inhibitory effect of the endowment effect diminishes with age. This study helps to rationally view the value of abandoned land and provides a new research perspective for parcel redistribution.

Survey of mosquito species in intensive pig farms in Hunan province, China.

Mosquitoes (Diptera: Culicidae) are one of the most studied groups of arthropods worldwide due to their high transmission capacity for pathogens, including viruses and parasites. During June to October 2022, the prevalence of mosquito species in 12 intensive pig farms from 12 representative administrative regions in Hunan province of China was investigated using traps with ultraviolet light. All collected mosquitoes were counted and identified to species according to morphological and molecular methods. A total of 4,443 mosquito specimens were collected in the pig farms, and they represented one family, four genera and nine species. Culex pipiens pipiens (24%) was the most common mosquito species, followed by Armigeres subalbatus (23.4%) and Culex tritaeniorhynchus (20.6%). Phylogenetic analyses based on mitochondrial cox1 sequences revealed all mosquito species from present study grouping into distinct monophyletic groups corresponding to nine known mosquito species with strongly supported. The results of the present investigation have implications for the ongoing control of mosquito infestation in pig farms in Hunan province, China. This is the first report of mosquito populations in intensive pig farms in Hunan province, China.