IB Environmental systems and societies 5.2B Agriculture Systems Notes

Agricultural Systems Vary Across the World Due to Soil and Climate Differences

1. Agricultural systems differ because soil and climate vary widely across the world and set physical limits on which crops and livestock a place can support.
2. Soil fertility, texture, structure, drainage, and depth determine which crops grow well and how much yield the land can produce.
3. Climate restricts the crops and livestock that can survive, through temperature, rainfall, humidity, and frost.
4. Farmers adapt their practices to local conditions, producing systems such as terrace farming, irrigation, dryland pastoralism, and intensive crop production.

How Soil Differences Shape Farming

1. Fertile soils support intensive cropping, while poor or shallow soils suit pastoralism or low-input farming.
2. Tropical rainforest soils (Oxisols) are nutrient-poor because heavy rain leaches minerals away, so farming needs shifting cultivation or added fertilizer.
3. Temperate grassland soils (Mollisols) hold high organic matter, allowing extensive cereal production such as wheat, barley, and maize.
4. Mountain soils are thin, stony, and erosion-prone, limiting farmers to grazing or terrace farming.
5. Alluvial soils near rivers are fertile and hold reliable moisture, supporting rice cultivation in monsoon regions.

How Climate Differences Shape Farming

1. Climate sets the length of the growing season, which limits how many harvests a year are possible.
2. Tropical climates allow several cropping cycles a year, while cold climates may allow only one short season.
3. Hot, wet regions support plantation crops such as sugar cane, bananas, and cocoa.
4. Dry regions with low rainfall rely on pastoralism, drought-resistant crops, and irrigation.
5. Extreme climates such as deserts and tundra limit farming to highly adapted systems or need technological help.

Farming Adapts to the Soil and Climate of Each Biome

1. Tropical Rainforests
   1. Soil: nutrient-poor Oxisols, highly weathered, acidic, and low in minerals.
   2. Climate: hot and humid with high rainfall, giving rapid nutrient cycling but also heavy leaching.
   3. Crops: bananas, cocoa, coffee, and cassava.
   4. Challenges: deforestation, poor soil retention, and reliance on shifting cultivation.
   5. Regions: the Amazon, the Congo Basin, and Southeast Asia.
2. Temperate Grasslands
   1. Soil: deep, fertile Mollisols rich in organic matter.
   2. Climate: moderate temperatures, distinct seasons, and adequate rainfall.
   3. Crops: wheat, corn, barley, and soybeans.
   4. Challenges: soil erosion from intensive farming and monoculture risks.
   5. Regions: the North American Prairies, the Eurasian Steppes, and the Pampas.
3. Deserts
   1. Soil: sandy, saline, low in organic matter, with poor water retention.
   2. Climate: extreme temperatures and very low rainfall.
   3. Crops: date palms and drought-resistant grains such as millet and sorghum.
   4. Challenges: water scarcity and dependence on irrigation.
   5. Regions: the Sahara, the Arabian Desert, and the Mojave.
4. Mediterranean
   1. Soil: thin, rocky, and erosion-prone but moderately fertile.
   2. Climate: hot, dry summers and mild, wet winters.
   3. Crops: grapes, olives, citrus fruits, and almonds.
   4. Challenges: water shortages, soil degradation, and wildfires.
   5. Regions: southern Europe, California, South Africa, and Australia.
5. Tundra
   1. Soil: permafrost with very low fertility and poor drainage.
   2. Climate: cold temperatures and short growing seasons.
   3. Crops: very limited, mostly small-scale greenhouse farming.