APHG Unit 5 Agriculture

14.1 Consequences of Agricultural Practices: Altering the Environment

• Overall Theme: Agricultural practices, driven by the need to feed a growing global population, significantly alter landscapes, both positively and negatively, with lasting environmental and societal consequences.

• Agricultural Landscapes: These are landscapes that result from the interactions between farming activities and a location’s natural environment. They can be long-standing or constantly changing.

• Shifting Cultivation:

  • Practiced in peripheral/semi-peripheral countries (South America, Africa, Southeast Asia).
  • Involves farming land until infertile, then abandoning it.
  • Differs from crop rotation; focuses on land recovery.
  • Can lead to soil degradation if fallow periods are insufficient.
  • Can be part of a sustainable agroecosystem when managed well.
  • Example: Ban Tat community in Vietnam.

• Slash and Burn:

  • Considered a type of shifting cultivation, but can permanently alter landscapes.
  • Common in tropical wet climates.
  • Involves cutting/burning forests to create fields.
  • Ash provides nutrients, but soil fertility is quickly depleted.
  • Contributes to deforestation and soil erosion.
  • Can be sustainable if practiced by small populations, with adequate land recovery time.
  • Example: Hin Lad Nai village in Thailand.

• Terracing:

  • Carving hillsides into level growing plots.
  • Used in mountainous areas, including tropical wet climates.
  • Creates paddies for water-intensive crops (e.g., rice).
  • Preserves soil nutrients and slows rainwater runoff.
  • Labor-intensive but can make unusable land productive.
  • Critical to maintain to prevent runoff and mudslides.
  • Example: Ifugao Rice Terraces in the Philippines.

• Irrigation:

  • Supplements rainfall by bringing water to fields.
  • Transforms arid/semi-arid landscapes.
  • Supports both subsistence and commercial farms.
  • Reservoirs (artificial lakes) and rerouted water paths are common.
  • Aral Sea Example: Diversion of rivers for cotton irrigation led to drastic shrinkage and ecological damage.
  • Colorado River Example: Heavily dammed and used for irrigation, serving millions of people and farmland; threatened by agricultural demands and dams’ effects.
  • Ogallala Aquifer Example: Overdrawn, leading to water level declines in the Great Plains.
  • China Example: Groundwater irrigation leads to CO2 emissions; South-to-North Water Diversion Project faces criticism for being less effective than agricultural water conservation.
  • Increased food production demands will strain water sources; better water management is crucial.

• Draining Wetlands:

  • Historically viewed as acceptable to create farmland.
  • Netherlands is a prime example of wetland reclamation.
  • Results in habitat loss, increased flood damage, reduced water quality, and release of stored carbon.
  • Example: Palm oil plantations in Malaysia.
  • Significant wetland loss in the U.S.
  • Australia is working with farmers to adopt sustainable practices.

• Pastoral Nomadism:

  • Extensive practice, generally subsistence agriculture.
  • Herders move animals seasonally for grazing.
  • Practiced in dry climates (Southwest Asia, North Africa, Arctic).
  • Traditional practices aim to preserve resources.
  • Disruption can lead to land degradation, overgrazing, and desertification.
  • Can impact biodiversity and cause soil erosion.
  • Evolving due to modernization and urbanization.
  • Mongolia Example: Migration patterns remain the same, despite using motorcycles.
  • Tuareg Example: Cattle-dependent nomads in the Sahara struggling due to declining rainfall and overgrazing around wells.