Decrease In Population Density Research Articles

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation.

Queen conch are among the most economically, socially, and culturally important fishery resources in the Caribbean. Despite a multitude of fisheries management measures enacted across the region, populations are depleted and failing to recover. It is believed that queen conch are highly susceptible to depensatory processes, impacting reproductive success and contributing to the lack of recovery. We developed a model of reproductive dynamics to evaluate how variations in biological factors such as population density, movement speeds, rest periods between mating events, scent tracking, visual perception of conspecifics, sexual facilitation, and barriers to movement affect reproductive success and overall reproductive output. We compared simulation results to empirical observations of mating and spawning frequencies from conch populations in the central Bahamas and Florida Keys. Our results confirm that low probability of mate finding associated with decreased population density is the primary driver behind observed breeding behavior in the field, but is insufficient to explain observed trends. Specifically, sexual facilitation coupled with differences in movement speeds and ability to perceive conspecifics may explain the observed lack of mating at low densities and differences between mating frequencies in the central Bahamas and Florida Keys, respectively. Our simulations suggest that effective management strategies for queen conch should aim to protect high-density reproductive aggregations and critical breeding habitats.

Idea paper: Controlling trait adaptation to decrease population densities for conservation and management

AbstractEcologists and evolutionary biologists have revealed that adaptive microevolution (i.e., allele frequency changes through time) and behavioral changes occur rapidly enough to affect contemporary ecological dynamics, and we can consider rapid adaptation for better conservation and management of wild populations. However, previous studies tended to focus on adaptation that increases population densities (e.g., evolutionary rescue), and did not pay attention to adaptation that decreases population densities (e.g., evolutionary suicide). Here, we demonstrate that controlling trait adaptation may be potentially important for decreasing population densities. One possibility is introducing “selfish” genotypes to populations. If the genotypes increase their reproductive success at the expense of population growth (e.g., cheaters in subsocial ants or coercive males in damselflies), we can decrease population densities (intraspecific adaptation load). The other possible option is diverting trait values of animals from the value that maximizes population growth (ecological trap). For example, we may be able to change behavior of a deer population by hunting so that they will not approach the best habitat with ample resources (landscape of fear). Then, we can consider the optimal allocation of our effort to directly decrease their population densities and control their trait values. However, we should carefully conduct controlling trait adaptation because it may result in unintended outcomes through modified genetic compositions and behaviors, such as increasing genetic variation of the focal population that enhances adaptation to changing environments by introducing selfish genotypes or a transient increase of population densities by modified behaviors.

Building in or out? Examining urban expansion patterns and land use efficiency across the global sample of 466 cities with million+ inhabitants

Expansion of urban areas accompanied by decreasing population density results in inefficient urban growth from a spatial-ecological perspective. This study examines variations in the urban expansion patterns across 466 world cities with million + inhabitants in terms of the contribution of three growth modes (infilling, edge expansion, and outlying) and its relationship with urban land use efficiency, measured in terms of urban density. Focusing on two different time periods (1985–2000 and 2000–2015), it has been found that cities that experience inward expansion are largely located in the Global North, while cities in the Global South experience comparatively more outward than inward expansion. We also find a positive relation between inward expansion and the annual change rate of urban density. However, we hypothesize that this is largely attributed to pronounced variations in the initial per capita land consumption, particularly between cities located in the Global North and Global South. Indeed, when we examine the effect of NDEI on the end-point urban density, and control for the initial urban density, a different conclusion is achieved. We find that in the Global North, more inward expansion of cities decreases urban density compare to the subgroup of cities located in the Global South in which inward expansion amplifies urban density. Understanding such differential effects of urban expansion patterns on urban density is important for our advancement towards sustainable development goal indicator 11.3.1.

Dissolved Metal (Fe, Mn, Zn, Ni, Cu, Co, Cd, Pb) and Metalloid (As, Sb) in Snow Water across a 2800 km Latitudinal Profile of Western Siberia: Impact of Local Pollution and Global Transfer

Snow cover is known to be an efficient and unique natural archive of atmospheric input and an indicator of ecosystem status. In high latitude regions, thawing of snow provides a sizable contribution of dissolved trace metals to the hydrological network. Towards a better understanding of natural and anthropogenic control on heavy metals and metalloid input from the atmosphere to the inland waters of Siberian arctic and subarctic regions, we measured chemical composition of dissolved (<0.22 µm) fractions of snow across a 2800 km south–north gradient in Western Siberia. Iron, Mn, Co, Ni, and Cd demonstrated sizable (by a factor of 4–7) decrease in concentration northward, which can be explained by a decrease in overall population density and the influence of dry aerosol deposition. Many elements (Mn, Ni, Cu, Cd, Pb, As, and Sb) exhibited a prominent local maximum (a factor of 2–3) in the zone of intensive oil and gas extraction (61–62° N latitudinal belt), which can be linked to gas flaring and fly ash deposition. Overall, the snow water chemical composition reflected both local and global (long-range) atmospheric transfer processes. Based on mass balance calculation, we demonstrate that the winter time atmospheric input represents sizable contribution to the riverine export fluxes of dissolved (<0.45 µm) Mn, Co, Zn, Cd, Pb, and Sb during springtime and can appreciably shape the hydrochemical composition of the Ob River main stem and tributaries.

Research on Urban Expansion and Population Density Change of an Urban Agglomeration in the Central‐Southern Region of Liaoning Province, China

The relationship between urban expansion and population density changes is complex and plays a fundamental role in urban sustainable development research. This relationship has been studied in multiple large cities. However, there is no report of the relationship of the two factors mentioned above in urban agglomeration in a particular region of China. Ten cities located in the central‐southern region of Liaoning province are selected as research samples in this study. The spatial growth rate and urban compactness index of the sample cities were calculated using the land use and population data of these cities in three time phases: 1995, 2005, and 2015. Then, the geographical growth features, the population density changes, and the link between these two in the sample cities were investigated at these three periods. Our results revealed that the studied cities of central‐southern Liaoning province expanded at the three time phases under the driver of positive population density growth, but the effects of urban population change on urbanization growth modes across time were uneven across different periods. Our study showed a trend that active transition of different urbanization growth modes was associated with decreased population density.

Effects of environmental factors on reproductive potential of the Gulf of Maine northern shrimp (Pandalus borealis)

The northern shrimp (Pandalus borealis) once supported a significant winter fishery in the Gulf of Maine (GOM). However, the population collapsed in 2012 and a fishery moratorium has been in effect since 2014 due to record low levels of spawning stock biomass and persistent recruitment failure. An important parameter in determining population dynamics, fecundity, has not been evaluated for more than 30 years, during which time the GOM has warmed significantly. In this study, we quantified three reproductive characteristics related to fecundity: potential fecundity (PF, number of viable eggs), relative fecundity (RF, number of viable eggs per gram of body weight), and egg size (ES) for GOM northern shrimp. The results showed that PF was strongly related to body size, while RF was independent of body size. Egg size declined with increasing body size for larger females. Egg size is related to size at larval hatch, suggesting that although larger females produced more eggs, those eggs may produce smaller larvae. In contrast with previous studies, PF and RF were positively correlated with bottom temperature in the relatively warm years of our study. We hypothesize that the positive temperature-fecundity relationship we observed may not reflect a direct effect, but possibly a compensatory response relating to decreased population density during the time period of our study. In addition, the environmental effects we observed may to some extent reflect progression of the inshore migration of females. The information derived in this study can help us have a better understanding of environmental effects on reproductive potential for climatically vulnerable species such as the GOM northern shrimp.

Effect of Sub-Zero Treatments and Tempering on Corrosion Behaviour of Vanadis 6 Tool Steel.

Sub-zero treatment of Vanadis 6 steel resulted in a considerable reduction of retained austenite amount, refinement of martensite, enhancement of population density of carbides, and modification of precipitation behaviour. Tempering of sub-zero-treated steel led to a decrease in population density of carbides, to a further reduction of retained austenite, and to precipitation of M3C carbides, while M7C3 carbides precipitated only in the case of conventionally quenched steel. Complementary effects of these microstructural variations resulted in more noble behaviour of sub-zero-treated steel compared to the conventionally room-quenched one, and to clear inhibition of the corrosion rate at the same time.

“Polarized Landscape”: Half a Century Later

—The article is devoted to the polarized landscape concept (also known as the polarized biosphere concept), developed by the author in 1970. The socioeconomic conditions for implementation of the conceptual project are considered, as well as changes in these factors and corresponding fundamental concepts over the past half century. It is demonstrated how the ideal model of the territorial structure of the cultural landscape is related to the lifestyle of its creator; how his ideas about work and leisure formed the pattern of a regular network of cities surrounded by buffer functional zones with decreasing population density from the center to the periphery, occupied by natural parks and reserves. The big city and wildlife are considered the equivalent poles of the biosphere. The author traces how Russia’s transport infrastructure has changed and how modern transport policy, at least in Moscow and Moscow Oblast, contradicts the ideas of a polarized biosphere. At the same time, the growth of territorial contrasts of socioeconomic development leads to growth of the so-called inner periphery, where the processes of restoration of natural landscapes proceed spontaneously as the anthropogenic load decreases. Some polarization of the landscape favorable for the biosphere, occurs by itself, and this process should not be hindered. The author traces the relationship of his concept with classical works on theoretical geography, in particular, with The Isolated State by I. von Thünen; he talks about the history of penetration of the polarized biosphere into the national geographical science, and outlines paths for further development of this project.

Ecology of outbreak populations of the western spruce budworm

AbstractWe sampled outbreak populations of western spruce budworm, Choristoneura occidentalis (Lepidoptera: Tortricidae), between 1997 and 2016 in Douglas‐fir forests in the interior of British Columbia, Canada. Annual rates of change in population densities were correlated with generation survival, modulated by egg recruitment via dispersal of moths. Most temporal variation in generation survival was the result of variation in survival of small, non‐feeding larval stages. Survival rates of feeding larval and pupal stages determined the magnitude of generation survival but contributed little to temporal trend. Survival of small larvae was the product of density‐related losses of larvae dispersing to and from hibernation sites and weather‐related stress caused by warm temperatures in late summer and early spring. Overwinter survival improved in cooler years and at higher elevations. Survival of feeding larvae and pupae was associated with mortality by natural enemies, in particular a few species of dominant, ubiquitous endoparasitoids, and an episodic, virulent baculovirus. Recruitment of eggs indicated emigration of gravid moths independent of defoliation but proportional to density of local moths. During periods of increasing and decreasing population densities over a large outbreak area, a marked differential in adult densities among locations resulted in greater than expected per‐capita egg recruitment to areas of relatively low density and vice versa, indicative of net exchange of gravid moths from high‐ to low‐density populations. The result was homogenization of egg densities among locations, apparent synchrony of the outbreak at the large scale, and extended duration of the outbreak at some locations, despite declining generation survival. These results are compared with field studies of the closely related spruce budworm, Choristoneura fumiferana. We suggest our interpretation applies more generally and outbreaks of conifer‐feeding budworms are maintained for several years by compensatory survival of sequential life‐history stages and spatio‐temporal smoothing of densities via dispersal of gravid moths. Parasitoids and pathogens can cause sudden declines in densities, but populations inevitably wane as a result of cumulative degradation of their resource. The interaction and temporal sequence of bottom‐up and top‐down factors explain the similarities and differences in outbreak characteristics within‐ and among‐budworm species.

Effects of anthropogenic habitat disturbance on the home range size and habitat preference of the Eastern box turtle (Terrapene carolina carolina)

Abstract: The Eastern box turtle (Terrapene carolina carolina) is a vulnerable species with decreasing population density from anthropogenic development and habitat loss. To determine the impact of electric utility pole replacement and vegetation maintenance on the home range size and habitat preference of T. carolina carolina, we radio-tagged 13 box turtles and located them weekly from April to November 2019, recording several habitat measurements at each location. We performed a principal component analysis of vegetation data and estimated home range size using 95% minimum convex polygon (MCP), kernel, and Brownian-bridge methods. Our data indicate that turtles prefer shrub cover and avoid rocky areas. While there was no significant difference between male and female home range size, a post hoc analysis dividing females into right-of-way (ROW) and non-ROW groups revealed a significant difference in female home range size, which may result from accessibility of higher-quality nesting sites within the ROW compared with surrounding forest stands.

Density dependence can obscure nonlethal effects of disturbance on life history of medium-sized cetaceans.

Nonlethal disturbance of animals can cause behavioral and physiological changes that affect individual health status and vital rates, with potential consequences at the population level. Predicting these population effects remains a major challenge in ecology and conservation. Monitoring fitness-related traits may improve detection of upcoming population changes, but the extent to which individual traits are reliable indicators of disturbance exposure is not well understood, especially for populations regulated by density dependence. Here we study how density dependence affects a population’s response to disturbance and modifies the disturbance effects on individual health and vital rates. We extend an energy budget model for a medium-sized cetacean (the long-finned pilot whale Globicephala melas) to an individual-based population model in which whales feed on a self-replenishing prey base and disturbance leads to cessation of feeding. In this coupled predator-prey system, the whale population is regulated through prey depletion and the onset of yearly repeating disturbances on the whale population at carrying capacity decreased population density and increased prey availability due to reduced top-down control. In populations faced with multiple days of continuous disturbance each year, female whales that were lactating their first calf experienced increased mortality due to depletion of energy stores. However, increased prey availability led to compensatory effects and resulted in a subsequent improvement of mean female body condition, mean age at first reproduction and higher age-specific reproductive output. These results indicate that prey-mediated density dependence can mask negative effects of disturbance on fitness-related traits and vital rates, a result with implications for the monitoring and management of marine mammal populations.

Do Castanea sativa wild provenances influence Dryocosmuskuriphilus Yasumatsu (Hymenoptera: Cynipidae) infestations?

The Asian chestnut gall wasp (ACGW), Dryocosmus kuriphilus, native to China was accidentally introduced into many countries worldwide, including Italy. Different susceptibilities have been reported in literature among cultivated plants belonging to different gene pools worldwide, but this aspect has not been sufficiently explored among wild chestnut populations. The aims of this multiyear study were (i) to assess differences in susceptibility to ACGW in wild C. sativa plants coming from different parts of Europe grown in an experimental plot in Central Italy, (ii) to preliminarily analyse the relationships between temperature, relative humidity and rain variables of winter and summer and D. kuriphilus infestation. Provenances coming from Greece reported a significantly smaller number of galls than the Italian and Spanish ones in the three-years of survey, showing a lower susceptibility to ACGW attacks in respect of plants coming from Italy and Spain. Interannual variation of ACGW infestation in the chestnut provenances may be influenced by the local environmental conditions. A hot and dry summer, occurred in 2015, could be responsible for a marked decrease in ACGW population density during 2016. The results lead to suppose that the different genotypes considered have different reactions depending on environmental conditions and ACGW attacks.

Insect Decline-A Forensic Issue?

Simple SummaryNumerous studies report a decline in insect biodiversity and biomass on a global scale. Since forensic entomology relies on the presence of insects, the question of whether this discipline will be or already is affected by such a decrease is not only posed to investigative authorities and the public, but also to the scientific community. While the data does indeed provide overwhelming evidence of insect decline, even if the methods of evaluation and data pooling are occasionally questioned, only a few studies deal with forensically relevant insects. These few data do hardly prove a decrease in forensically relevant insect species so far. However, one factor driving insect decline is likely to have also a strong influence on necrophagous insects in the future: climate change.Recent reports have shown a dramatic loss in insect species and biomass. Since forensic entomology relies on the presence of insects, the question is whether this decline effects the discipline. The present review confirms that numerous studies document insect population declines or even extinction, despite the fact that the rates of decline and the methods used to demonstrate it are still much debated. However, with regard to a decline in necrophagous insects, there is little or only anecdotal data available. A hypothetical decrease in species diversity and population density in necrophagous insects could lead to a delayed colonization of dead bodies and a modified succession pattern due to the disappearance or new occurrence of species or their altered seasonality. Climate change as one of the drivers of insect decline will probably also have an impact on necrophagous insects and forensic entomology, leading to reduced flight and oviposition activity, modified growth rates and, therefore, an over- or underestimation of a minimum postmortem interval. Global warming with increased temperature and extreme weather requires a better understanding about necrophagous insect responses to environmental variations. Here, transgeneration effects in particular should be analysed in greater depth as this will help to understand rapid adaptation and plasticity in insects of forensic importance.

Evaluation The Effect of Intercropping Garlic with Grapevines on Productivity, Phytoremediation, Competitive Indices and Plant Parasitic Nematode Community تقييم تأثير تحميل الثوم مع العنب على الإنتاجية والمعالجة النباتية والعلاقات التنافسية ومجتمع النيماتودا المتطفلة على النبات

The present investigation was carried out during winter of the consecutive seasons (2018/2019 and 2019/2020) on 9 year old Flame Seedless grapevines grown in a private vineyard at Sharkia Governorate, Egypt. Garlic (Balady cv) was intercropped with grapevines (Flame Seedless cv) on dripper irrigation lines, as a try to reduce numbers of phytonematodes in grapevine soil. For grapevines, the obtained results referred that intercropping insignificantly (P≤0.05) increased number of berries/bunch, weight of 100 berries and berry firmness, separation force, total soluble solids percentage, anthocyanin content and yield/ vine as well as bunch weight and width, berry length, berry diameter and berry shape index compared to sole grapevines. For garlic (Balady cv), the achieved results pointed out that plant height, number of leaves/plant, leaf fresh weight/ plant, nick diameter as well as bulb diameter, height and weight/ plant insignificantly decreased when garlic intercropped with grapevines compared to control. Competition indices; i.e., land equivalent ratio (LER), area time equivalent ratio (ATER) and land utilization efficiency (LUE) showed that, intercropping garlic with grapevines was more efficient than sole cropping system. Aggressively estimation demonstrated that grapevines were dominant advantages while garlic was dominated. Moreover, intercropping garlic (Balady cv) with grapevines was obviously decreased population density of phytonematodes infesting grapevine orchard. Generally, garlic together with other biocontrol agents in grapevine orchards has the potential to be an efficient and environmentally agricultural management method to reduce numbers of plant parasitic nematodes.

Geographic Distribution of Foot and Ankle Orthopedic Surgeons Throughout the United States.

Background:At present, the geographic distribution of orthopedic foot and ankle (OFA) surgeons in the United States is poorly defined. The purpose of this investigation is to determine the geographic distribution of OFA surgeons in the United States. We hypothesize that there will be differences in OFA surgeon density throughout the United States and that economic factors may play a role in access to subspecialty OFA care.Methods:A current membership list was obtained from the American Orthopaedic Foot & Ankle Society (AOFAS). Active members were categorized relative to states and US congressional districts, using publicly available census data. The relationship between income and surgeon density was determined using a Pearson correlation.Results:We identified a list of 1103 active AOFAS members. There was an average of 0.38 and 0.40 OFA surgeons per 100 000 people in each state and congressional district, respectively. We found a weak negative relationship demonstrating that regions with higher levels of poverty had fewer OFA surgeons, with a Pearson correlation coefficient of –0.14 (95% CI: –0.24, –0.04), P = .008.Conclusion:There is wide geographic variation of OFA surgeon density throughout the United States. Regions with higher levels of poverty were weakly associated with decreased population density of OFA surgeons compared to regions with lower poverty levels. Understanding these trends may aid in developing both recruitment and referral strategies for complex foot and ankle care in underserved regions.Level of Evidence:Level V.

The impact of an African swine fever outbreak on endemic tuberculosis in wild boar populations: A model analysis.

A mathematical model is developed and analysed to examine the impacts of African swine fever (ASF) introduction into a wild boar population that supports endemic animal tuberculosis (TB). TB is a widespread infectious disease caused by the Mycobacterium tuberculosis bacteria belonging to the Mycobacterium tuberculosis complex (MTC) that can persist in reservoir wildlife hosts. Wild boar (sus scrofa) are a key reservoir for MTC, and an increasing trend in wild boar density is expected to lead to an increase in TB prevalence with spill-over to livestock. MTC infection is presently controlled through a variety of strategies, including culling. African swine fever (ASF) is a virulent, viral infection which affects wild boar and is spreading across Eurasia and Oceania. ASF infection leads to near 100% mortality at the individual level, can cause a dramatic decrease in population density and may therefore lead to TB control. We extend an established model that captures the key demographic and infection processes for TB in wild boar to consider the impact of ASF introduction on wild boar populations that support different levels of endemic TB. Our model results indicate that an ASF infection will reduce wild boar population density and lead to a decrease in the prevalence of TB. If ASF persists in the local host population the model predicts the long-term decline of TB prevalence in wild boar. If ASF is eradicated, or fades-out in the local host population, the model predicts a slower recovery of TB prevalence in comparison to wild boar density after an ASF epidemic. This may open a window of opportunity to apply TB management to maintain low TB prevalence.

Activity Time Budgets—A Potential Tool to Monitor Equine Welfare?

Simple SummaryHorses’ behavior is a good indicator of their welfare status. However, its complexity requires objective, quantifiable, and unambiguous evidence-based assessment criteria. As healthy, stress-free horses exhibit a highly repetitive daily routine, horses’ time budget (amount of time in a 24 h period spent on specific activities) can assist in equine welfare assessment. A systematic review of the literature yielded 12 papers that assessed equine time budgets for eating, resting and movement for a minimum of 24 continuous hours. A total of 144 horses (1–27 years old), 59 semi-feral and 85 domesticated horses, are included in this review. The reported 24 h time budgets for eating ranged from 10% to 66.6%, for resting from 8.1% to 66%, for lying from 2.7% to 27.3%, and for movement from 0.015% to 19.1%. The large variance in time budgets between studies can largely be attributed to differences in age and environmental conditions. Management interventions (free access to food, increased space, decreased population density) in domesticated horses yielded time budgets similar to semi-feral horses. The data support the importance of environmental conditions for horses’ well-being and the ability of time budgets to assist in monitoring horses’ welfare.Horses’ behavior can provide valuable insight into their subjective state and is thus a good indicator of welfare. However, its complexity requires objective, quantifiable, and unambiguous evidence-based assessment criteria. As healthy, stress-free horses exhibit a highly repetitive daily routine, temporal quantification of their behavioral activities (time budget analysis) can assist in equine welfare assessment. Therefore, the present systematic review aimed to provide an up-to-date analysis of equine time budget studies. A review of the literature yielded 12 papers that fulfilled the inclusion criteria: assessment of equine time budgets for eating, resting and movement for a minimum of 24 continuous hours. A total of 144 horses (1–27 years old), 59 semi-feral and 85 domesticated horses, are included in this review. The 24 h time budgets for foraging or eating (10–6.6%), resting (8.1–66%), lying (2.7–27.3%), and locomotion (0.015–19.1%) showed large variance between studies, which can largely be attributed to differences in age and environmental conditions. Management interventions in domesticated horses (ad libitum access to food, increased space, decreased population density) resulted in time budgets similar to their (semi-)feral conspecifics, emphasizing the importance of environmental conditions and the ability of time budgets to assist in monitoring horses’ welfare.

Estimating national and local low-voltage grid capacity for residential solar photovoltaic in Sweden, UK and Germany

The electric grid’s available capacity to accommodate solar photovoltaic on national scales is currently uncertain. This makes decisions about grid capacity expansion, which can be very costly for local grid operators, difficult to make. Yet, knowledge of national solar photovoltaic grid capacity is central in order to formulate realistic solar PV targets and strategies. We present a methodology based on publicly available data to estimate the grid’s hosting capacity of residential solar photovoltaic at both the national and local scale. The model is applied to Sweden, Germany and the UK and shows that low-voltage grid capacity for residential solar photovoltaic is very large, 33 (+5/-7) GW (Sweden), 248 (+5/-24) GW (Germany) and 63 (+1/-14) GW UK, and similar to current total generation capacity. Based on our estimations, we find that with the capacity of the present grid Sweden can supply 24%, Germany 60% and UK 21% of their current annual net electricity consumption from residential solar photovoltaic. In addition, we find that the grid-supported individual solar PV system sizes increase as population density decreases. Finally, our work highlights the importance of implementing sizing incentives for customers when installing their solar PV systems.

False Seedbeds Reduce Labor Requirements for Weeding in Chile Pepper

This study evaluated false seedbeds, which are sequences of irrigation and tillage that eliminate weed seedlings before crop planting, to reduce requirements for hand hoeing in chile pepper (Capsicum annuum). To address this objective, a field study was conducted near Las Cruces, NM from July 2015 to Oct. 2016 (experimental run 1) and July 2016 to Oct. 2017 (experimental run 2). False seedbeds were designed to target weeds that typically emerge after chile pepper planting. This was done by implementing false seedbeds the summer before chile pepper seeding. During chile pepper seasons, data included repeated measures of weed seedling emergence, amounts of time required for individuals to hoe field sections (i.e., hoeing time), and yields of two chile products: early harvest of green fruit and late harvest of red fruit. Hoeing time and yield data were included in cost–benefit analyses that also incorporated expenses and revenues projected by crop budget models for the study region. Results indicated false seedbeds caused a 54% decrease in weed population density during the chile pepper season of experimental run 1; however, for experimental run 2, false seedbeds did not affect cumulative weed seedling emergence. For both experimental runs, false seedbeds reduced hoeing times, suggesting that false seedbeds affected hoeing by means other than reduced weed density. After accounting for costs for implementation, false seedbeds reduced hand hoeing costs by $262/acre to $440/acre. These reductions in hoeing costs coincided with improved profitability in all but one combination of year and product. Green fruit yield was lower in false seedbed plots in experimental run 1; however, false seedbeds did not affect green fruit yield in experimental run 2, or red fruit yield in both experimental runs. These results indicate that false seedbeds implemented the summer before planting are promising techniques for reducing labor requirements for weeding in chile pepper production.

Some aspects of the role of agricultural production for sustainable development of the state

The author draws attention to the development of crisis phenomena in most of the developed countries of the world. Possible scenarios for resolving the growing crisis contradictions are briefly analyzed. It is noted that quite serious armed conflicts are not excluded, in which a drop in the standard of living of the population of many countries of the world is inevitable. It is noted that in this scenario, the developed agriculture will contribute to the minimum inevitable losses among the population of those countries that will be involved in the conflict. In a scenario in which armed clashes will not be a serious enough problem for developed countries, there will be a problem of a decrease in the number of the indigenous population of these countries, their replacement by a population with other cultural traditions, or, in general, a critical decrease in population density. The author analyzes the reasons for this phenomenon and comes to the conclusion that it is possible to reverse the current trend by involving the population in the development of agriculture on modern principles.