Agriculture and Environment

4 Key excerpts on "Agriculture and Environment"

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  eBook - ePub

  Food Security

  • Bryan L. McDonald(Author)
  • 2013(Publication Date)
  • Polity

    (Publisher)

  Drawing on the great wealth of information that now exists on the causes and impacts of global environmental change, the chapter reviews the environmental impacts agriculture and food production practices have had on the environment. The chapter considers environmental impacts in five major sectors: land and soil; water use and water quality; habitat and biodiversity loss; energy use; and climate change. The chapter concludes with a discussion of ways to reduce the environmental impact of agriculture and food production. This discussion focuses particular attention on the need to develop food systems that provide for human needs while also aiding efforts to both mitigate and adapt to processes of global environmental change, a process that I argue can be harmonized with efforts to increase agricultural sustainability.

  Impacts on land and soil

  Covering only about one-third of the earth’s surface, land is indispensable to agriculture and livestock production. These land resources, according to a definition by UNEP (2002) include soil, land cover, and landscapes. Land and soil provide a range of additional benefits, including regulating hydrological cycles and aiding in the preservation of biodiversity, carbon storage, and other ecosystem services (the resources and process provided by natural systems that are beneficial to human livelihoods and well-being). Though finite, the functional amounts of land and soil resources, along with water and nutrients, are, as Smil (2000) asserts, variable with management practices that considerably affect their quality and efficiency of use. Many current agricultural practices reduce the ability of ecosystems to provide goods and services such as carbon sequestration and soil retention and absorption of water. The amount of land under agricultural cultivation has increased steadily in developing regions while remaining largely constant in developed regions, with the largest gains in cultivable land made in the mid-twentieth century (UNEP 2008). Degradation and pollution of land resources, such as the overuse of fertilizers and other chemicals, has also occurred as a result of policy failures and unsustainable agricultural practices (UNEP 2002). Human induced land modification, largely related to agricultural activities, has impelled significant environmental changes (Smil 2000; UNEP 2002, 2008).

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  Encyclopedia of Soil Science

  • Rattan Lal(Author)
  • 2017(Publication Date)
  • CRC Press

    (Publisher)

  ] With losses of farmland to degradation and urbanization and little new agricultural land to develop, meeting the needs of future populations for food, fiber, and other agricultural products depends on a significant increase in crop yields. Under food production practices, this yield increase spells greater use of inputs (e.g., energy, fertilizer, and pesticides) and raises the question of the environmental costs of increased production.

  Agriculture and EnvironmentAL SUSTAINABILITY

  To a large extent, the economic and social viability of agriculture depends on the sustainability of the resources that agriculture both depends on and affects. Farmers have always intuitively known that good soil quality underpins the success of their operations, and soil conservation programs in many countries throughout the 20th century supported this recognition. Since the late 1980s, interest has grown in a fuller accounting of the environmental costs of agricultural production. These costs include declining water quality and competition for finite water resources, declining air quality, emission of greenhouse gases, loss of wildlife habitat, and decline in species and genetic diversity.[ 3 ] To a large extent, conserving and enhancing soil quality can mitigate these costs.

  Soil

  Agricultural land management in the past has taxed the soil system, often withdrawing more than it has returned. In particular, mechanical cultivation and the continuous production of row crops have resulted in the displacement and loss of soil by erosion, large decreases in soil organic matter, and a concomitant release of carbon (C) as carbon dioxide into the atmosphere.[ 4 ] The inventories of soil productive capacity indicate human-induced degradation on nearly 40% of the earth’s arable land as a result of land clearing, extensive soil cultivation, soil erosion, atmospheric deposition of pollutants, overgrazing, salinization, and desertification.[ 5 ] The projected doubling of the human population in the 21st century threatens even greater degradation of soils and other natural resources.[ 6 ]

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  Environmental and Natural Resource Economics

  A Contemporary Approach

  • Jonathan M. Harris, Brian Roach(Authors)
  • 2021(Publication Date)
  • Routledge

    (Publisher)

  Chapter 20 ). Most of China and the Indian subcontinent are close to the limits of their available water supply, and urban/industrial water demand is rising steadily. Much of Africa is arid or semiarid, as are large areas in West and Central Asia and in the western United States. Climate change, as noted earlier, is likely to intensify problems of water availability, as precipitation patterns change and mountain snowpack is lost. Given the clear economic incentives to expand irrigation, both the externality and the common property resource problems associated with water use mean that this expansion is likely to intensify resource and environmental problems.

  16.5 Sustainable Agriculture for the Future

  All the problems discussed to this point are related to the spread of high-input industrial agricultural techniques. Some of the problems can be mitigated through increased efficiency—reducing fertilizer, water, and pesticide use while increasing output. But there are alternative approaches to agricultural production, which suggest a more dramatic change in agricultural production systems. Ecological analysis offers us a somewhat different understanding of the relationship between agriculture and the environment. Rather than seeing agricultural production as a process of combining inputs (including land, water, fertilizer, and pesticides) to maximize output, the analysis known as agroecology suggests that agriculture has to be understood as a process of intervention in the natural biophysical cycles responsible for plant growth.33 These include the carbon cycle, nitrogen cycle, water cycle, and similar cycles for other plant nutrients.

  In a natural state, solar energy drives these cycles. Traditional agriculture departs little from these natural cycles. Modernized agriculture relies on extra inputs of energy, water, nitrogen, and synthetic chemicals. This gives higher yields but creates imbalances in all the natural cyclical processes. From this perspective, soil degradation, fertilizer and pesticide pollution, and water overdraft are results of disrupting natural cycles. To use another ecological concept, modern agriculture expands carrying capacity but does so at the cost of increasing ecological stresses.

  Both the economic and the ecological perspectives can influence our definition of sustainable agriculture

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  Principles of Sustainable Development

  • F. Douglas Muschett(Author)
  • 2017(Publication Date)
  • CRC Press

    (Publisher)

  Many viewpoints exist with regard to sustainable development. Such viewpoints or perspectives are not independent but are rather intertwined to provide a particular person’s view of sustainable development. The ecological perspective is an essential viewpoint; however, it is only one of several important viewpoints and must be placed in context to be fully understood.

  In a survey of definitions for the term “sustainable agriculture,” Neher concluded that there were three common themes in such definitions: plant and animal productivity, environmental quality and ecological soundness, and socioeconomic viability.17 Three definitions of sustainable agriculture illustrate these themes:

  …Sustainability refers to the ability of an agroecosystem to maintain production through time, in the face of long-term ecological constraints and socioeconomic pressures.18

  Sustainable agriculture is a complex concept incorporating ecological stability and reliance (e.g., conservation of resources and reduction of impacts on the environment), economic viability, the quality of life, and human welfare.10

  Sustainable agriculture over the long-term enhances environmental quality and the resource base upon which agriculture depends, provides for basic human food and fiber needs, is economically viable, and enhances the quality of life for farmers and society as a whole.19

  We believe the third definition best describes our concept of sustainable agroecosystems, but we would add a wildlife component to the definition. We should also acknowledge that agriculture was developed as an enterprise of human activity to even out environmental and economic risk while maintaining a productive base over time.

  The ecological perspective is one of three key conceptual issues or sets of objectives with potentially important operational implications for sustainable development(Figure 2.1 ). Substantial effort has been invested to ascertain the implications inherent in the three components of sustainable development.20 Ecologists stress preserving the integrity of ecological systems that are critical for the overall stability of our global ecosystem and deal in measurement units of physical, chemical and biological entities.9

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