Environmental Impacts of Agricultural Practices (College Board AP® Human Geography)

Impacts of Agricultural Practices

• Different agricultural practices alter the landscape in unique ways, including: 

  • slash-and-burn

  • terracing

  • irrigation

  • deforestation

  • draining wetlands

  • shifting cultivation

  • pastoral nomadism 

Slash-and-burn

• In slash-and-burn agriculture, vegetation is cut down and then burned to clear land for agricultural production

• Slash-and-burn agriculture causes a temporary increase in soil fertility due to the burned organic matter 

• However, over time, there are several negative effects of the practice

Negative impacts of slash-and-burn

• Deforestation

  • Forests are often cleared for agricultural activity, such as livestock grazing or slash and burn agriculture, or logging

  • This negatively affects the local ecosystem and biodiversity, as well as contributes to climate change

• Loss of biodiversity

  • Decreased biodiversity can result in food insecurity because of overreliance on single types of crops and loss of genetic diversity within crops

  • In addition to habitat destruction and loss of wildlife, loss of biodiversity can also limit the local environment’s ability to:

    • filter water (loss of marine life)

    • filter carbon (loss of plant life and forests)

    • pollinate crops (loss of bird and insect life)

• Soil erosion

  • Soil erosion may lead to decreased agricultural productivity and less fertile soils, reducing crop production

  • It can also contribute to desertification

• Increased carbon emissions

  • Increased carbon emissions, due to deforestation, industrial production, and the use of fossil fuels has negative effects on the environment and climate change

Terraced farming

• In terraced farming, terraces are built into mountainous areas to make the land more suitable for agriculture

  • Crops are then grown on the sides of hills or mountains by planting on man-made steps (terraces)

• Terraced farming increases the agricultural output of the land and decreases soil erosion

  • However, it requires large amounts of labor and maintenance

Irrigation

• Irrigation refers to the controlled application of water to agricultural land to aid in plant growth

• While irrigation can allow for agricultural production in otherwise arid areas that would not support crops, it also has potentially negative effects including:

  • depletion of water from springs and other natural sources

  • negative impacts on ecosystems because of the diversion of water

  • oil salinization from overuse

Image: Irrigation on a potato field, Spain

Deforestation

• Deforestation refers to the cutting down of forest areas for agricultural production or livestock grazing

• Plant, animal, and insect species are lost due to deforestation, contributing to a loss of biodiversity

• The additional release of carbon dioxide as a result of less forest also contributes to climate change

Draining wetlands

• The draining of wetlands removes water so the area can be used for agricultural production

• Draining wetlands increases the amount of arable land and, potentially, carrying capacity

• Negative effects include: 

  • loss of biodiversity among marine and bird species

  • the potential for increased flooding

Shifting cultivation

• In shifting cultivation, farmers grow crops on one plot of land before moving on to new fields when soil fertility declines and allowing fields to lay fallow to recover soil nutrients

• Shifting cultivation is often associated with slash-and-burn agriculture 

• Negative effects can include:

  • loss of biodiversity

  • long-term depletion of the soil, leading to soil exhaustion 

Pastoral nomadism

• Pastoral nomadism refers to the herding of animals across large areas in search of pasture land

• Overgrazing can lead to desertification