Effects of Farming and Seedling-raising Methods on Population Growth and Grain Yield of Mechanized Transplanting Rice

The effects of farming method, rice variety and seedling-raising method were studied on the population growth quality and grain yield of the mechanized transplanting rice by way of three-factor split plot design. The results showed that the no-tillage mechanical transplanting treatment was poorer than the conventional mechanical transplanting treatment in transplanting quality in general, but the former was similar to the latter in population growth quality. In regard to grain yield, the no-tillage mechanical transplanting treatment was lower than the conventional me- chanical transplanting treatment. Raising both pot-mat seedling and plastic-tray seedling did not make much difference in population growth and grain yield of mechanized transplanting rice, so both of the seedling-raising methods can be adopted according to practical conditions.

Population Growth and Sustainability of Common Property Resource Management Systems in the Eastern Hindu Kush:The Use of Communal Fodder Resources in Mehlp Valley,North Pakistan

In common property studies,increasing number of users has been considered as a major threat for the long-term sustainability of natural resources. This perception has been true in a few cases. However,the 40-years empirical research conducted in a variety of environmental settings,reveals that population pressure is not the only factor responsible for the degradation of natural resources. In remote areas,where the local inhabitants highly depend on available natural resources for subsistence livelihood,the economically important resources are kept under different ownership regimes. The local inhabitants have established autochthonous insti-tutions,and formulated rules and regulations for proper management of these resources. In this paper an attempt has been made to explore the response of a small fodder user community to the increasing population. For this purpose a micro-level study has been conducted in a remote mountain environment in the eastern Hindu Kush. For this research,data has been collected through fieldwork and focus group discussion. The results of this study reveal that fodder user communities have responded very well to the problem of population pressure. To maintain equity and long-term sustainability they have adopted a number of strategies including changing the ownership,and a resource kept under private ownership at the time of low population has been changed to a common property with increase in population. Based on this study it can be concluded that in mountainous areas and fragile environment the local inhabitant have both the capacity and capability to change their behaviour with regard to changing resource productivity as well as increasing number of users,and this situation does not always lead to the tragedy of commons.

Population growth，economic growth，technology changes in relation to environmental changes──A theoretical modelling analysis of environmental changes

This paper mainly deals with the impact of three major factors , namely population growth,economic growth and technology changes, on the changes of environmental quality. It presents a curve ofenvironmental changes in relation to demographic transition and process of industrialization. It concludesthat a major way of improving environmental quality is to intensify pollution decreasing technical factorsand that control of population growth will also reduce the pressure on the environment.

Effect of bis(tributyltin)oxide on reproduction and population growth rate of calanoid copepod Schmackeria poplesia

A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis（tributyltin） oxide （TBTO）. The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L＂1 were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1. The percentages of ovigerous females were reduced compared with the control （P〈0.01） after 24 days exposure to concentrations higher than 10 ng TBTO L-1. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase （rm）, from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration （60 ng LI）, where all females aborted their egg sacs, 20 ng TBTO L-1 was the only concentration that significantly decreased rm compared with that of control （an effect associated with decreased sex ratio）. The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.

Changes of population growth in Tibet Autonomous Region

The population of the Tibet Autonomous Region which is thinly scattered, is almost entirely Tibetan. The unique high and cold climate, varied and changeable topography and social economic and human environment restrict population mobility in the region. Historically there were little statistic documents and the early data about population scale is poorly reliable. After the peaceful liberation of Tibet in 1951, its population went up continuously, and the growth rate has been higher than the national average level since 1964. The general tendency was that the pattern of population increase had changed within a short period. At first, the death rate was lowered quickly and the natural population increase speed was quickened, then, the death rate was lowered further, and the birth rate began to rise at a quick speed. After 1970, both the death rate and birth rate was generally stable, the level was relatively lower than before, the death rate slowed down at a quicker speed than the birth rate. The natural population increase rate rose extremely slowly, which formed the population development situation of fast but steady increase. The future population development tendency is that, the quick increase tendency characterized by young population will continue for quite a long time, and the pressure of future population increase upon resources environment will become increasingly great. The age structure and sex composition of population in Tibet, rather low since long time ago, became increasingly high upon entering the 1980s, but it was still the lowest one compared to other provinces or regions in China. The main reason is due to the low sex ratio of Tibetan infants and children caused by the low sex ratio of newly born infants and the high death rate of male infants, which will slow down the population increase in a limited way. There are few barren lands appropriate for farming and there exist many restricting factors for cultivation or utilization. With further increase in Tibetan population, it is inevitable that per capita available cultivated land will drop continuously. The problem of food supply in Tibet will still be the main issue in its regional development with the increase of population. It is impossible to support a quickly increasing population with the limited agricultural resources in Tibet. Therefore, the population development direction of Tibet can only be to tighten quantity control and to popularize family planning knowledge among Tibetan people. It is a fundamental strategic policy for the social and economic development in Tibet if family planning can be followed progressively on a voluntary basis.

Effects of algal concentration and initial density on the population growth of Diaphanosoma celebensis Stingelin(Crustacea,Cladocera)

The effects of algal concentration and initial density on the population growth of the estuarine cladocera, Diaphanosoma celebensis Stingelin, were evaluated in an indoor experiment. A 2 × 4 layout that included two algal concentrations （Chlorella pyrenoidosa, 1 × 10^6 and 3 ×10^6 cell/mL） and four inoculation densities （100, 200, 300 and 400 ind./L） were established. Diaphanosoma celebensis were reared in 150 mL flasks containing 50 mL of algal medium at 22℃, under salinity of 10 and a photoperiod of 12 h L： 12 h D. The lag phase required to initiate continuous population growth following inoculation was shorter for D. celebensis fed 1 × 10^6 cell/mL and inoculated at 300 or 400 ind./L than that for D. celebensis fed 3 × 10^6 cell/mL and inoculated at 100 or 200 ind./L. However, D. celebensis fed 3 × 10^6 cell/mL and inoculated at 100 or 200 ind./L exhibited longer periods of positive population growth The maximum population densities were 5 875 ± 324, 6 690 ± 691, 7 735 ± 1,121 and 6 365 ± 691 ind./L for D. celebensis fed 1 × 10^6 cell/mL and inoculated at 100, 200, 300 and 400 ind./L, respectively, and 15 070 ± 379, 12 215 ± 648, 11 960±2,551 and 16 130 ± 880 ind./L for D. celebensis fed 3 ×10^6 cell/mL and inoculated at 100, 200, 300 and 400 ind./L, respectively. The average daily increasing rates of population were 0.076 ± 0.001, 0.065 ± 0.002, 0.055 ±0.002 and 0.048 ± 0.003 for D. celebensis fed 1×10^6 cell/mL and inoculated at 100, 200, 300 and 400 ind./L, respectively, and 0.098± 0.001, 0.078 ± 0.002, 0.072 ± 0.003 and 0.067 ± 0.003 forD. celebensis fed 3 × 10^6 cell/mL and inoculated at 100, 200, 300 and 400 ind./L, respectively. The maximum population density and average daily increasing rate of population increased as the algal concentration increased, whereas an increase in the inoculation density led to a linear decrease in the daily increasing rate of population under both algal concentrations. The results of the present experiment indicate that the algal concentration and inoculation density significantly affect population growth of D. celebensis, Furthermore, the results suggest that the optimal algal concentration and inoculation density for the mass culture ofD. celebensis should be 3 × 10^6 cell/mL and 100 ind./L.

The effect of the causative algae of large-scale HAB in the East China Sea on egg hatching of Argopecten irradians, and population growth of Brachionus plicatilis and Moina mongolica

The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monocuhure and mixture of the two species were examined on the egg-hatching success ofArgopecten irradiarts Lamarck, and the population growth of Brachionus plicatilis MUller and Moina mongolica Daday. The results showed that monocuhure of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities （ED50） inhibiting the egg hatching success of A. irradhms for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm^3 , respectively. Monoculture of P. dongha/ense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis （ 1 × 10^4 ～ 3 ×10^4 cells/cm^3 ） and M. mongolica （2 × 10^4～5 ×10^4 cells/cm^3 ） ; P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis （4 × 10^4 ～ 10×10^4 cells/cm^3 ） and M. mongolica （ 10 ×10^4 cells/cm^3）. When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.

Population Growth,Available Resources,and Quality of Life:China’s Post-Reform Economic Development

Two opposing intellectual traditions and their contem-porary developments regarding the relations among population, available resources, and quality of life as reflected in economic growth are reviewed. What is at issue is whether population growth is detrimental to or beneficial for economic development. Neither of the extreme views gives a complete picture of the interplay among population, resources, and quality of life. Following previous literature on the topic, this paper establishes a more balanced approach that considers the function linking population and quality of life not constant but variable and regards the limitedness of resources as not absolute but relative to regions and societies. The proposed approach is more flexible in better explaining the relation between population and economic growth. China is examined as a case in point to shed light on the interaction of population growth, economic development, and available resources, and its recent post-economic reform experiences showcase the appropriateness of the synthetic approach.

Discussing why population growth is still ignored or denied

Due to a number of factors outlined in this article,the issue of population growth is excluded from the sustainability discussion.In this article,we explore some of the ethical presumptions that underlie the issues linking population growth and sustainability.Critics argue that action to address population creates social and economic segregation,and portray overpopulation concerns as being "anti-poor," "anti-developing country," or even "antihuman." Yet,de-linking demographic factors from sustainability concerns ignores significant global realities and trends,such as the ecological limits of the Earth,the welfare and long-term livelihood of the most vulnerable groups,future prospects of humanity,as well as the ecosystems that support society.

The Role of Nuclear Regulators in Reviewing Population Growth Projections

One of the roles of nuctear regulators is to review population projections calculated by applicants for populations lying in the vicinity of nuclear power plants. This paper examines methods of calculating rates of growth and thus calculating future population growth. This paper is concerned about regulators making sure that nuclear power plants are not located near densely populated centers and that population centers located near nuclear power plants do not become densely populated. In the case of El Dabaa city in the north coast of Egypt, south west of the nominated plant site, three rates of growth 1.5%, 2.5% and 3% were identified. The first is the current population growth rate of the city, the second is the average national growth rate and the third is the expected growth rate of the city when the nuclear power plant gets constructed and operated. In all three cases, this city is a population center and rules of distance from the nuclear power plant shall apply. Thus the further natural growth of this city should be controlled and directed away from the downwind of the plant.

Trends of Population Growth in China:Maximum Number Will Exceed 1.5 Billion

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Population Aging and Control of Population Growth

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The Control of Population Growth Is the Function of the Central Government

Mr.Jiang Zcmin,Gencral-Seerctary of the Cen-tral Committee of the Chincse Communist Party and.Chairman of the People's Republic of China,in a rC-ccnt spcech cm phasized that the family planning pro-gramme should be strictly and effectively im plemented in 1994,a year of crucial importance for promoting re-form and opening and thc drive lowards.modernization.To makc continucd contributions to the sociocconomic development in the country,we must fulfil the plan for controlling population growth..The spcech was delivcred at the anua!National Fo-rum on Family Planning Work convened jointly by the Party's Central Committcc and the Statc Council.

Exploring detailed urban-rural development under intersecting population growth and food production scenarios: Trajectories for China’s most populous agricultural province to 2030

Henan,China,is likely the most populous agricultural province worldwide.It is China’s major grain-producing area,with a continuously increasing population(96 million),which is greater than 93%of countries worldwide.However,this province has been experiencing unprecedented urbanization recently due to national policies and measures,such as a plan to build the capital city of Henan into a national center,resulting in severe conflicts in land use that endanger food security regionally and globally.To facilitate decision-making on this problem,we explored the detailed urban-rural development of Henan by modeling these land-use conflicts.Conventional modeling of a region’s urban-rural development is to navigate trade-offs(a)solely between different land-use types(b)by assuming that each type provides a single service(e.g.,croplands produce all the food),and(c)under a polynomial regression-based projection of population.In contrast,we considered both land-use type and intensity,resulting in a detailed land system for Henan.By introducing the concept of land system services(e.g.,food production),we established a many-to-many relationship between land system classes and services.These allowed us to carry out the most comprehensive modeling of Henan’s urban-rural development under eighteen combined scenarios of population growth and land-use policies on food production.The modeling results of these scenarios provide a solid basis for making decisions regarding Henan’s urban-rural development.We also revealed the influence mechanism of population growth,land-use policies,and their combinations,highlighting the benefits of securing food production by agricultural intensification rather than merely expanding the area of cropland.

The effect of Common Cuckoo parasitism on the annual productivity of a host population

Avian interspecific brood parasitism is an excellent system for studying coevolutionary processes in nature because brood parasites directly affect host reproductive success.Most research on avian brood parasitism has,therefore,focused primarily on specific host anti-parasite behaviours and parasite counter-adaptations.However,the population-level consequences of brood parasitism for host species are poorly understood.This study investigated the effect of Common Cuckoo(Cuculus canorus)parasitism on the productivity of a local population of the Great Reed Warbler(Acrocephalus arundinaceus)host in south-western Slovakia.A total of 495 females nesting at the studied site successfully fledged 1321 of their own young and 63 young of the Common Cuckoo over the course of 15 years(2008-2022),and the annual rate of successful parasitism ranged from 18% to 44% over this period.As predicted,higher rates of successful cuckoo parasitism significantly reduced the annual productivity of the local Great Reed Warbler population,and its contribution to decreased host reproductive success was at about the same rate as overall nest failure caused by predation and other environmental factors.Such a heavily parasitized population was probably maintained by immigrants from other populations and density-dependent selection,which is also consistent with source-sink dynamics.However,further long-term studies monitoring parasitized populations are required to confirm these findings.

China's different spatial patterns of population growth based on the “Hu Line”

The "Hu Line" has been regarded as one of the greatest geographical discoveries in China because it reveals the significant spatial relationship between human activity and natural environment. The spatial evolution of population on both sides of the "Hu Line" has had important implications for both urbanization and regional development and has attracted widespread attention during the dramatic economic and social changes since the implementation of reform and opening-up policy in China in 1978. Using Geographical Information System(GIS) techniques, this paper studied the stability of the "Hu Line" and the spatial patterns of population growth on each side by constructing a spatial database of China's census data from 1982 to 2010. The findings are as follows:(1) In the last 30 years, the "Hu Line" has remained relatively stable, but a new tendency of population change has begun to emerge. The population ratio either side, namely, the southeast half(SEH) and the northwest half(NWH), of the "Hu Line" remains at roughly 94:6(SHE : NWH). Noteworthy, the proportion of population in the SEH of the "Hu Line" has been decreasing slightly, while that in the NWH has been increasing slightly, as the latter has benefited from its higher rate of natural population growth.(2) The spatial patterns of population growth on both sides of the "Hu Line" were quite different. The degree of population concentration in the SEH increased faster than the NWH. Regions with a negative population growth rate have rapidly expanded; these were mainly located in the south of the "Qinling Mountains-Huaihe River belt" and northeastern China. Meanwhile, regions with a fast population growth rate were mainly concentrated in the Yangtze River Delta, the Pearl River Delta, and the Beijing-Tianjin metropolitan area. Thus, the spatial pattern of population growth in the SEH presented a concentration pattern that could be called "Matthew effect pattern".(3) The spatial pattern of population growth in the NWH could be regarded as the "Relative Balance pattern." In the NWH, the population growth rate was positive and the degree of population concentration was very low. There were many minority populations located in the NWH that usually lived in a dispersed pattern but had a higher rate of natural population growth due to the preferential population policy. There were also some regions with a negative rate of population growth in the NWH, which were mainly located close to the "Hu Line" and the Ancient Silk Road.(4) In the future, the spatial patterns of population growth on both sides of the "Hu Line" may continue to evolve. For the SEH, the capacity to attract more people to small and medium-sized cities and towns should be enhanced. For the NWH, the emphasis should be placed on promoting urbanization and enhancing population agglomeration in its major cities.