Agricultural Population Density

6 Key excerpts on "Agricultural Population Density"

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  eBook - ePub

  Population Geography

  A Systematic Exposition

  • Mohammad Izhar Hassan(Author)
  • 2020(Publication Date)
  • Routledge India

    (Publisher)

  In the case of Egypt, while the crude density is only 93, physiological density works out to be nearly 3,498 thousand persons per square kilometres of arable land according to PRB, 2017. This measure is very appropriate for a situation where agriculture is the mainstay of population. But it is also true that not all the people in a region or country are dependent on agriculture. Thus, physiological density also does not provide an accurate picture of population pressure on land. As a further refinement, agricultural density is worked out which refers to a ratio between the number of people earning their living or subsistence from working the land and the total amount of farmland. In the economically advanced countries, agricultural densities are very low as compared to the less advanced countries. As cultivable and cultivated areas of a region or country are generally not of uniform value, agricultural density does not provide an exact account of man-land relations. Vincent, a French geographer, in 1946, therefore, suggested an index, which he termed as comparative density (Clarke, 1972:30). In the calculation of comparative density, total population of a region is related to the aggregate of weighted land under cultivation according to its productivity. Thus, it is type of physiological density taking into account the varying levels of productivity of cultivated lands in any area. It is worthwhile to note here that the measures of density discussed earlier are of no practical value for areas which are more urbanised and industrialised. In the developed countries of the West vertical expansions of residential complexes invalidate the relationship between population and areas, and these measures, therefore, reveal nothing about the concentration of people within buildings

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  eBook - ePub

  An Introduction to Population Geographies

  Lives Across Space

  • Holly R. Barcus, Keith Halfacree(Authors)
  • 2017(Publication Date)
  • Routledge

    (Publisher)

  These include proximity to resources, historical distribution of lands and land tenure issues, transportation systems, distribution of amenities and individual preferences. They are inextricably entangled with the arenas of life course construction outlined in Section 2.3. In South America, for example, the population is not evenly distributed but clustered along the coastlines and a few interior cities, leaving large areas of low population density. Knowing the extensiveness of the Amazon rainforest and the difficulty of living in the Andes mountains, for example, gives immediate physical geographic clues to these spatial patterns, even if these factors alone are unable to explain the full picture. Figure 3.2 World population distribution 2015. Data Source: Center for International Earth Science Information Network (CIESIN), Columbia University; United Nations Food and Agriculture Programme (FAO); Centro Internacional de Agricultura Tropical (CIAT) 2005; SEDAC. Fortunately, Geographers’ methods to measure population density and distribution have evolved as rapidly as the populations being measured. Censuses (Box 3.2), population registers and surveys that count the number of people who reside in a particular area help production of density measures. Advanced technologies, such as satellite images and aerial photography, can further be employed for population estimation. For example, Rindfuss et al. (2002) utilized Geographic Information Systems and remote sensing to link data about changes in village practices and landscape change in Nang Rong, Thailand. Similarly, Fox (2002) utilized aerial photography and socioeconomic data to assess the multiple dimensions of land change, including the implications of land tenure policies, on land use practices in several villages in northeastern Cambodia

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  eBook - ePub

  An Introduction to Agricultural Geography

  • David Grigg(Author)
  • 2003(Publication Date)
  • Routledge

    (Publisher)

  Chapter 12 Population, labour supply and agriculture

  Much has been written on the relationships between population growth and food supply, rather less on the influence of population growth and regional differences in density upon farm structure and land use. Yet differences in the amount of labour used in agricultural production are of paramount importance in determining spatial differences in the way farming is carried on. In this chapter a brief account of world differences in agricultural densities is given, followed by an outline of Ester Boserup’s theory that links changes in land use intensity to population increase. Some empirical relationships between population density and agricultural characteristics are then discussed.

  AGRICULTURE AND ECONOMIC DEVELOPMENT

  Two centuries ago, four-fifths of the working population of most countries in the world were engaged in agriculture. Since then, Europe, North America, Japan, the Soviet Union and Australasia have experienced industrialization. During this process the absolute numbers working in manufacturing industry and the services have increased, and the proportion engaged in agriculture has fallen to below 15 per cent in most of these countries, and to less than 3 per cent in the United Kingdom, Belgium and the USA. Elsewhere, industrialization is in its early stages, and the proportion engaged in agriculture remains high, particularly in Asia and tropical Africa (Figure 12.1 ). In all the developed countries, the numbers employed in agriculture are now in rapid decline (Figure 12.2); industry has offered higher wages than agriculture, and the introduction of laboursaving machinery has reduced the need for labour on farms. But this is a relatively recent trend. In the early stage of industrialization, Phase I, the agricultural population increased (Figure 12.3),

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  The Dynamics of Agricultural Change

  The Historical Experience

  • David Grigg(Author)
  • 2019(Publication Date)
  • Routledge

    (Publisher)

  10 one of the earliest workers on this topic, assumed that the inherent physical characteristics of the land determined the length of fallow. He then determined by survey methods: the acreage of crops necessary to maintain a family; the proportion of the area that can be cultivated; the amount of fallow necessary to allow the regeneration of vegetation and hence soil fertility. From these data he then calculated the area of crops and fallow necessary for a given soil type, and from this the carrying capacity as a density. This could then be compared with the actual density. Similar calculations have been made for parts of Brazil and the New Guinea Highlands.

  Since these early works there have been criticisms of the method and attempts to expand the concept in order to incorporate differing concepts of subsistence and varying levels of labour intensity.11

  The symptoms of overpopulation12

  On the whole the methods of defining rural overpopulation outlined in the preceding sections have received more criticism than praise. Further, and very much to the point, they need statistical information that has rarely been available in the past. Thus many historians, and indeed those who describe contemporary events, have used as evidence of the existence of overpopulation adverse features of the land use, structure and technology which they believe are a result of population growth (Figure 2 ). However there is always the possibility that these diagnostic characteristics are a result of some other economic force.

  The subdivision of farms

  A major determinant of spatial variations in farm size in the modern world is population density, and in particular the density of the agricultural population upon the available agricultural land. If population grows and the area of farm land is not increased, or increases less rapidly than the demand for farms, farms will be subdivided. Over time the average size of farm will fall. This has happened in many parts of the developing world in the last thirty years; it seems to have happened in parts of Europe during past periods of population growth, although it must be admitted that data on farm sizes before the nineteenth century are incomplete and unsatisfactory. However differences in land tenure may influence the degree of subdivision. Thus where all the farmers are owner-occupiers the amount of subdivision will depend on whether primogeniture or equal inheritance is practised. If primogeniture is practised and the farm passes to the eldest son, then subdivision will not occur, however rapid population growth. On the other hand if equal inheritance is practised then subdivision is inevitable. Where farms are rented from a landlord a variety of effects may be found. Thus in eighteenth- or nineteenth-century England landlords rented land to those tenants with the capital and skill to guarantee a good rent, and arranged their estate in farms whose size depended on economic and managerial principles; they felt no obligation to provide land for a growing agricultural population. On the other hand in medieval Europe landlords provided some land for their dependants, and may even have felt obliged to do so. In nineteenth-century Ireland landlords – for the most part English – did not object to the subdivision of the estates as population grew. In contemporary Latin America much land is held in very large holdings, and landlords feel no need to provide land for the rapidly growing agricultural population.

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  A Concise History of World Population

  • Massimo Livi Bacci(Author)
  • 2012(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  15

  It is important to understand the logic of the link between development and demographic growth. How can increasing population pressure and the consequent straining of available resources possibly constitute the prerequisite for development? A recent theory proposed by Ester Boserup explains this relationship with reference to agricultural economies.16

  The variable population density of rural areas is naturally associated with the fertility of the land: high density in areas of rich, easily irrigated soil; decreasing density in areas less well suited to cultivation. This interpretation can, however, be reversed so that demographic growth is seen to create the conditions necessary for the adaptation of progressively more intensive methods of cultivation. Population pressure is then the cause and not the consequence of agricultural innovation.

  The various systems of land cultivation spread across a continuum that stretches from forest-fallow systems (slash and burn preparation of the terrain followed by one or two years of cultivation, and then a long fallow period of 20–25 years during which the forest reestablishes itself and the fertility of the soil is restored) at one end to multiannual cropping on the same piece of land at the other. Between the two extremes brush-fallow cultivation is identical in method to forest-fallow, but shorter, as a covering of shrubs reestablishes itself after six to eight years. In a short-fallow system (one or two years) there is only time for a grassy covering to grow back, while annual cropping allows but a few months for the soil to rest. Demographic growth determines the transition to progressively more intensive and shorter fallow cultivation systems which permit the feeding of a progressively larger population in a fixed area. This intensification process, however, is accompanied by an ever greater labor requirement and often also by declining worker productivity. For example, land preparation and the sowing of seed are extremely rudimentary in a slash and burn system: hatchet and fire clear the terrain of forest, ash fertilizes the soil, a pointed stick is all that is needed to sow the soft earth, and productivity per hour of work is high. Shorter fallow periods require more laborious soil preparation, and the simple action of fire must be replaced by work with hoe or plow; fertilization, weeding, and irrigation all become necessary. In a forest-fallow system, “fire does most of the work and there is no need for the removal of roots, which is such a time-consuming task when land has to be cleared for the preparation of permanent fields. The time used for superficial clearing under the system of forest fallow therefore seems to be only a fraction – perhaps ten or twenty per cent – of the time needed for complete clearing.”17

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  Demographics

  A Guide to Methods and Data Sources for Media, Business, and Government

  • Steven H. Murdock, Chris Kelley, Jeffrey L. Jordan, Beverly Pecotte, Alvin Luedke(Authors)
  • 2015(Publication Date)
  • Routledge

    (Publisher)

  Chapter 2 Basic Concepts, Definitions, and Geography of Demography As with any area of study, it is essential in demography to understand its basic concepts and the definitions of its key terms and to become familiar with the types of geographic areas for which demographic data are generally available. Knowing the jargon of demography and knowing the types of areas for which data can be obtained are essential first steps in knowing how to effectively use its data. In this chapter, we provide an overview of key concepts and definitions and examine the geographic bases used in demography and its applications. Basic Dimensions and Processes Given the definition of demography as the study of population size, distribution, and composition and of the processes that determine these, a logical place to begin in understanding demographic factors is to understand (1) what is meant by a population; (2) the three key dimensions of population–size, distribution, and composition; and (3) the three basic processes that determine population change–fertility, mortality, and migration. A population refers to the persons living in a specific area at a specific point in time. It refers to the aggregate, the group of people as a whole, in an area. As such, it has characteristics that are unique to an aggregate and are not just the sum of individuals’ traits or characteristics. For example, a population can have a death rate, birth rate, etc., but individuals are either alive or dead, have or have not been born. There is no death or birth “rate” for an individual

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