Agriculture is the deliberate effort to modify a portion of Earth’s surface through the cultivation of crops and the raising of livestock for sustenance or economic gain. Unit 5 explores how agriculture evolved, how agricultural products are distributed, and how farmers decide what to produce based on spatial land-use models.
Agricultural Revolutions
What are the three major agricultural revolutions?
- First (Neolithic) Revolution: The transition from hunting and gathering to settled farming, dating back approximately 10,000 years. Humans domesticated plants (seed crops and root crops) and animals, leading to surplus food and the rise of early civilizations.
- Second Agricultural Revolution: Coincided with the Industrial Revolution in Great Britain (17th–19th centuries). It introduced crop rotation, mechanization (plows, seed drills), and selective breeding, which dramatically increased yields and freed labor to work in industrializing cities.
- Third Agricultural Revolution (Green Revolution): Occurred in the mid-20th century. It introduced high-yield hybrid seeds, chemical fertilizers, pesticides, and advanced irrigation systems, preventing mass famine in developing countries (particularly Mexico, India, and the Philippines).
Types of Agriculture
What is the difference between subsistence and commercial agriculture?
- Subsistence Agriculture: Primarily found in developing nations. Farmers grow crops to feed themselves and their families, utilizing high amounts of manual labor and low capital/technology.
- Examples: Shifting cultivation (slash-and-burn), nomadic herding, and intensive subsistence wet rice farming.
- Commercial Agriculture: Primarily found in developed nations. Large-scale farming intended to produce food for sale off the farm, utilizing heavy machinery, biotechnology, and corporate management (agribusiness).
- Examples: Mixed crop and livestock, grain farming, dairy farming, Mediterranean farming, and commercial gardening (truck farming).
Von Thünen’s Land Use Model
What is the Von Thünen model?
Proposed in 1826, Von Thünen’s Model explains the spatial distribution of agricultural activities based on transportation costs and land rent. The model assumes a concentric ring pattern surrounding a central market city:
Center: Market City
Ring 1: Market Gardening & Dairying (perishable goods, high transport costs)
Ring 2: Forest / Wood (heavy, high transport costs)
Ring 3: Grains & Field Crops (less perishable, lighter to transport)
Ring 4: Livestock & Ranching (animals walk to market, requires vast cheap land)- Core Rule: Crop choice is determined by Bid-Rent theory — land closer to the city has higher rent, so only highly intensive, high-value, perishable crops (gardening/dairying) are grown close to the market. Extensively farmed crops (livestock/grains) are pushed outward where land is cheap.
Unit 5 Practice Questions
Question 1
According to Von Thünen’s model, why is forestry located in the second ring close to the market?
A) Wood requires intensive labor to cultivate
B) Timber is highly perishable and spoils quickly
C) Wood is heavy and expensive to transport over long distances
D) Trees require fertile soil only found near cities
Question 2
The Third Agricultural Revolution (Green Revolution) is best characterized by:
A) The initial domestication of seed crops and draft animals
B) The development of hybrid seeds, chemical fertilizers, and advanced irrigation
C) The migration of farmers from rural areas to industrializing cities
D) The rise of organic farming and local food movements
Answer Key
- C — Forestry is in the second ring because wood was used for heating and building, and its weight made long-distance transport extremely expensive.
- B — The Green Revolution introduced high-yield crop varieties and chemical inputs to raise global food production in the mid-20th century.