unit 7

• There are many environmental concerns related to land use including pollution, preservation of our biological resources, mineral and energy requirements, and food production
• Global land use


  • 12% used to cultivate food and fibre crops
  • 24% used for grazing livestock for the production of both meat and milk
  • 31% covered by forests
  • 33% consists of deserts, mountains, tundra and other land unsuitable for agriculture
• Main land uses in the Caribbean

  • Consumption (land that is used to generate goods and services e.g. housing and tourism)
  • Production (e.g. agriculture, forestry, mining and industrial land uses)
  • Conservation
• In Jamaica, it is estimated that in 2014 41% of all land is used for agriculture while 31% is covered in forests
• Agriculture


  The raising of plants and animals for food
• Between 1945 and the mid 1980's, the overriding aim of agricultural policies was to increase production resulting in mechanisation, use of artificial chemicals, animal and plant breeding, genetic engineering and monocropping
• Domesticated plants


  Plants that are cultivated and protected from natural competition with other plants and from plant-eating animals, and over time may become quite different from their ancestors
• Crop production


  1. Preparation

  2. Planting

  3. Growing

  4. Harvesting
• Types of agriculture


  • Subsistence agriculture
  • High input/industrialised or modern agriculture
  • Sustainable agriculture
• Subsistence agriculture


  The production of enough food to feed oneself and one's family with left over to sell or reserve for hard times
• High input/industrialised or modern agriculture


  Mostly practised by developed countries and relies on large inputs of energy in the form of fossil fuels to produce and run machinery, to irrigate crops and produce chemicals such as fertilizers and pesticides
• Mechanisation in modern agriculture

  • Use of machinery to replace manual labour
  • Increased productivity through larger, more effective equipment
• Mechanisation of the agriculture sector has led to the increasing use of monoculture – large areas of land dedicated to a single crop
• Monocultures may increase the risk of pest epidemics leading to increased use of pesticides
• Chemical fertilizers are often used in higher quantities to address deficiencies in particular soil nutrients
• Farmyard manure was replaced by inorganic fertilisers supplying nitrogen, phosphorus and potassium (N, P, K)
• A wide array of insecticides, herbicides and fungicides were developed which has had many benefits as well as drawbacks
• Demand for higher yields in the rearing of animals also led to the use of hormones designed to increase growth in animals, or to increase milk production
• The use of antibiotics as growth promoters and to treat diseases such as Salmonella is also a concern
• Genetic engineering in modern agriculture

  Useful genes can be transferred from one organism to the next
• Concerns are that genetically altered organisms might mutate (spontaneously change during copying), producing altered organisms which might cause unforeseen effects
• Introduction of genetically altered organisms into an ecosystem may also disturb natural population balances
• Sustainable agriculture


  The growing of crops and livestock in an environmentally friendly way using organic fertilisers, alternatives to pesticides and employing soil conservation methods to prevent or alleviate the problem of land degradation
• Land degradation


  The deterioration in the quality of land, its topsoil, vegetation, and or water resources caused by excessive or inappropriate exploitation
• Soil erosion


  The movement of soil components, especially surface litter and topsoil, from one place to another, mainly by flowing water and wind
• Human activities such as farming, logging, construction etc. can speed up soil erosion and destroy in a few decades what nature took thousands of years to generate
• Soil erosion is increased by large-scale mechanised operations causing a decline in soil fertility
• Sediments lost due to erosion may degrade water quality and is the largest source of water pollution globally