Knowt
Chapter 12 | Agriculture: Human-Environment Interaction
12.1 Agriculture and the Environment
Introduction to Agriculture
Agriculture: The purposeful cultivation of plants or raising of animals to produce goods for survival
The first crops to be harvested through agriculture were food crops, such as fruits, vegetables, grains, corn, wheat, and rice.
Other crops, such as oats and alfalfa, are important for feeding livestock.
Agriculture is more than growing food—though that is the primary purpose of farming and livestock-raising in many places.
Fiber crops, such as cotton, are used for textile and paper products.
Oil crops can be used for consumption or for industrial purposes.
Geographers study agriculture to understand how humans have modified the environment to sustain themselves.
Environmental Factors
Cultivating plants or raising animals requires adaptation to environmental limitations.
Sunlight, water, and soil quality all affect plant growth. Not all areas have equal amounts of each.
Agriculture is highly tied to the physical environment, and climate, elevation, soil, ad topography have a large effect on it.
You’ve read that climate is the long-term patterns of weather in a particular area.
Note: Weather is what happens in a short timeframe. Sunny, cloudy, raining, snowing, hot or cold, etc.
Climate influences agriculture because it determines the precipitation and temperatures in a given area.
Water provides the important moisture that plants and animals require.
Temperature determines the growing season—the length of the year during which plant life can grow.
Generally, the greater the distance from the Equator, the shorter the growing season.
At the Equator and in the tropics, the growing season can be year-round.
In the temperate and subarctic zones, however, the colder temperatures of winter prevent plant growth for varying times.
In those regions, the growing season is measured in the number of frost-free days, as frost can kill plants.
Elevation also affects the growing season and what plants can be grown.
Each increase of 1,000 feet upwards means a decrease of about 3.6° F in average temperature.
The higher the elevation, the shorter the growing season.
Elevation can create different cultivation opportunities in all mountainous regions.
At higher elevations, crops must be hardier. At certain heights, only grasses grow, so the land must be used for grazing livestock.
Soil is the biologically active coasting of Earth’s surface.
This layer can range from a few inches to several feet in depth.
Soil has four constituent parts: mineral particles, water, air, and organic matter.
The key characteristics of soil are its fertility, texture, and structure.
Topography is an areas land features, and can determine soil and water retention.
Slope also affects land productivity as it can face toward or away from sun.
The most favorable land for growing crops has ideal temperatures, precipitation, soils, and slope.
Sometimes landscapes are modified for better environmental factors.
Climate
Climate varies greatly and is based on four key factors: distance from the Equator, wind and ocean currents, proximity to large bodies of water, and topography.
These components interact with one another in different ways to create different climate regions.
Distance from the Equator determines the length of daylight and average temperatures.
Due to the tilt of the Earth, different parts of the globe receive more or less sun throughout the year.
Areas near the Equator get sun year-round. The further you get to the poles, stretches of minimal sun exposure become longer and more dramatic.
Ocean and wind currents circulate cold or warm water and air masses over Earth’s surface.
The circulation of water and air masses in turn affects patterns of temperature and precipitation.
Location relative to large bodies of water affects climate in two ways.
Bodies of water warm and cool more slowly than land, so most coastal areas tend to have milder climates.
Second, coastal areas are cooled during the day by cool winds displaced by warmer air rising from the water.
Location also affects precipitation, which tends to be heavier near coastlines.
Coastal mountains have much heavier precipitation on the side facing the wind.
Climate Regions
Climate region: An area that has similar climate patterns generally based on its latitude and its location on a coast or continental interior
Vladimir Köppen identified five broad climate types: tropical, dry, temperate, continental, and polar.
Tropical climates…
Warm temperatures all year-round
Vary in amounts of precipitation around the world
Dry climates…
Commonly found in continental interiors
Either arid or semiarid
Temperate climates…
Three basic types
Moderate temperatures and adequate precipitation
Long, warm summers and short winters
Mediterranean agriculture: An agricultural practice that consists of growing hardy trees and shrubs and raising sheep and goats
Polar climates…
Two kinds, tundra and ice cap
Extremely cold
Short, mild summer that is too cold for farming,
Rarely rises above freezing
Tropical climates…
Warm temperatures
Plentiful precipitation
Lots of global variation
12.2 Agricultural Practices
Subsistence Agriculture and Commercial Agriculture
Subsistence agriculture: An agricultural practice that provides crops or livestock to feed one’s family and close community using fewer mechanical resources and more people to care for the crops and livestock
Sometimes, harvests bring in more than is needed and farmers can sell the extra goods for cash.
Ultimately, subsistence farming is about producing enough to sustain you and your family or close community.
Generally uses fewer mechanical resources and more hand labor.
Other farmers grow crops and raise livestock for profit to sell to customers.
Commercial agriculture: An agricultural practice that focuses on producing crops and raising animals for the market for others to purchase
Subsistence and commercial agricultural practices help define the agricultural production regions.
Both subsistence and commercial agriculture are practiced at intensive and extensive scales.
Bid-rent theory: A theory that describes the relationships between land value, commercial location, and transportation (primarily in urban areas) using a bid-rent gradient, or slope; used to describe how land costs are determined
Where land value is high, farmers buy less land and use it intensively to produce the most output possible.
Where land is low value, farmers buy more land and use it extensively.
According to this theory, dairy and produce farmers, more concerned with quality, are willing to pay more for land close to the market.
Central business district (CBD): The central location where the majority of consumer services are located in a city or town because the accessibility of the location attracts these services
Intensive Agriculture
Intensive agriculture: An agricultural practice in which farmers expend a great deal of effort to produce as much yield as possible from an area of land
To achieve high productivity, intensive farmers rely on ‘inputs’ and energy.
In some regions, commonly used inputs include chemical fertilizers, pesticides, and growth regulators.
In other regions, inputs may be more natural like animal labor or care of the soil.
Large amounts of energy are always needed in intensive agriculture.
Technology and energy speed up the essential steps of farming.
These inputs and expenditures of energy maximize crop yields in intensive agriculture.
Intensive Subsistence Agriculture
When people work the land with lots of human labor for high crop yields to support their community, they are practicing intensive subsistence agriculture.
This type of farming feeds more than half the people living in densely populated semi-peripheral and peripheral countries.
As with any agriculture, the yields are affected by weather, seed quality, and use of fertilizers and pesticides.
When a farm that feeds people is negatively impacted, it can be disastrous for those who live off of its goods.
Fortunately, technology is aiding farmers in predicting weather and strategizing.
As populations increase, many farmers maximize food production by modifying the environment.
Intensive Commercial Agriculture
In some core countries, farmers engage in heavy investments for high yields to sell at market.
Intensive commercial agriculture often incorporates chemical fertilizers and machines.
It can be carried out close to or far from the market, depending on the good being produced.
Monocropping: The cultivation of one or two crops that are rotated seasonally
Monoculture: The agricultural system of planting one crop or raising one type of animal annually
Monocropping allows for specialization, simplifies cultivation, and maximizes efficiency.
Monocropping can strip soil of its nutrients, so there are ways of preventing this depletion.
Crop rotation: The varying of crops from year to year to allow for the restoration of valuable nutrients and the continuing productivity of the soil
The shift to monoculture also raises the stakes for farmers. As yields go up, crop prices can decrease.
Farmers must invest heavily in high-yield seeds, fertilizers, and pesticides.
Fertilizers and pesticides, while helping plants temporarily, can harm the soil long-term or contaminate water and hurt air quality.
Plantation agriculture: A type of large-scale commercial farming of one particular crop grown for markets often distant from the plantation
This type of intensive commercial agriculture typically takes place in peripheral and semi-peripheral economies
Plantation agriculture is one of the oldest forms of intensive commercial agriculture, with its roots going back to European colonization.
These former colonies continue to rely on production of cash crops, and their economies depend upon these neocolonial relationships.
Because plantation owners wish to ensure a steady stream of revenue and profit, they invest heavily in pesticides and fertilizers.
Plantations tend to be labor-intensive operations, but many being in peripheral countries, the cost of that labor is low.
Market gardening: A type of farming that produces fruits, vegetables, and flowers and typically serves a specific market or urban area
The practice of market gardening is driven by perishability and the demand for fresh produce.
Market gardeners often have to invest in technology like greenhouses to ensure constant production throughout the year.
They also need to use costly high-quality seeds and fertilizers and pesticides.
Successful market gardens cultivate relatively high yields on small tracts of land using intensive production methods.
Mixed crop and livestock systems: A type of farming in which both crops and livestock are raised for profit
There are two types of mixed farming: on-farm and between-farm.
On-farm farming entails the crops and livestock being raises on the same property.
In between-farm farming, two farmers share resources, one growing crops and the other raising livestock.
Mixing provides a farmer with certain advantages: part of the crop can be fed to the livestock, and the animals’ waste can be used to fertilize the crops
Extensive Agriculture
Extensive agriculture: An agricultural practice with relatively few inputs and little investment in labor and capital that results in relatively low outputs
Can be practiced in subsistence and commercial areas.
Found in peripheral and semi-peripheral countries, as well as the ranching practices of core countries.
Extensive Subsistence Agriculture
Extensive subsistence agriculture is often found in regions in which intensive subsistence agriculture is not feasible because the environment is marginal.
The carrying capacity is low in these areas.
Shifting cultivation: The agricultural practice of growing crops or grazing animals on a piece of land for a year or two, then abandoning that land when the nutrients have been depleted from the soil and moving to a new piece of land where the process is repeated
To work over time, shifting cultivation requires large land area.
Slash and burn: A method of agriculture in which existing vegetation is cut down and burned off before new seeds are sown; often used when clearing land
This helps maintain the land and results in nutrient rich ash fertilizer.
The land can then be used for several years until it is depleted, the process then repeated on new land.
Slash and burn has long been practiced, but is becoming unsustainable.
This method leaves the soil open to degradation and erosion.
It also leads to loss of habitat for animals and air pollution.
Nomadic herding: A type of agriculture based on people moving their domesticated animals seasonally or as needed to allow the best grazing
Prevents overgrazing as the herd is constantly moving into new lands.
Transhumance: The movement of herds between pastures at cooler, higher elevations during the summer months and lower elevations during the winter
Extensive Commercial Agriculture
Ranching is an extensive commercial farming practice.
It takes place in semiarid grassland areas around the world in which crop production is difficult or impossible.
A rancher can rely on as little labor investment as one cowhand for every 800 to 1,200 head of cattle.
Comparing Intensive and Extensive Agriculture
Many countries participate in a range of the aforementioned practices.
Physical geography is a major determinant of the agricultural practices used.
Large, nutrient-poor expanses of land available for growing crops call for extensive agriculture.
The only way to make up for the land’s low yield is to use more extensive lands, that don’t need much investment.
Rich soils are better suited to intensive agricultural practices because they can produce high yields.
Of course, inputs such as fertilizer or irrigation can be used to make deficient land more productive.
However, there are limits to what inputs can achieve.
Climate and natural occurrences are almost always more powerful than any preventative measure humans can try to instate.
Areas with marginal agricultural potential are generally only able to support small populations.
In contrast, areas with highly productive agriculture are able to support large populations.
Populous societies need intensive agriculture.
This situation generates a continued cycle.
Intensive agriculture generates high crop yields, which can support a large population.
A large population requires high yields, which means emphasizing intensive agriculture.
Agricultural Regions Around the World
In the late 1930s, an American geographer named Derwent S. Whittlesey developed a world agriculture map that identified 11 separate agricultural regions.
12.3 Agricultural Origins and Diffusions
Agricultural Hearths
Answering when, where, and why agriculture started is tricky.
People living in many different places domesticated different plants and animals at different times from about 11,000 to 1000 B.C.E.
Domestication: The deliberate effort to grow plants and raise animals, making plants and animals adapt to human demands and using selective breeding to develop desirable characteristics
From Foraging to Farming
Foragers: Small nomadic groups who had primarily plant-based diets and ate small animals or fish for protein
Humans lived as foragers for thousands of years.
They generally hunted small game but sometimes banded together to hunt larger animals.
Between 12-11 thousand years ago, Earth warmed considerably. Almost all of the massive glaciers covering the Northern Hemisphere melted.
Sea levels rose, and climate regions changed.
During these changes, people adapted accordingly.
The first animals to be domesticated were sheep and goats, which supplied hides, milk, and meat.
With the changing climate, people in Southwest Asia began to plant seeds to secure food supplies during the winter.
They chose grains that were plentiful and versatile to favor.
Through selective breeding people gradually improved the plants to increase both their yields and nutrition.
Ancient Hearths
Agricultural hearth: An area where different groups began to domesticate plants and animals
Scientists have identified several major agricultural hearths of domestication.
Domestication first took place in Southwest Asia.
Fertile Crescent: A hearth in Southwest Asia that forms an arc from the eastern Mediterranean coast up into what is now western Turkey and then south and east along the Tigris and Euphrates rivers to western parts of modern Iran
The people of this region grew wheat, barley, rye, and legumes and domesticated sheep, goats, cattle, and pigs.
Another agricultural hearth arose in Southeast Asia, where people raised pigs and grew sugarcane and root vegetables.
Domestication began there about 7000 B.C.E.
Ancient North Central China had two hearths with distinct crop types.
In South Asia, an agricultural civilization thrived in the Indus River Valley from 2500 to 1700 B.C.E.
These people farmed wheat, barley, peas, sesame, and possibly cotton, and domesticated cattle, fowl, pigs, camels, and buffalo.
In northern Central America and into southern Mexico, an agricultural hearth began about 8000 B.C.E.
People there grew sweet potatoes, beans, and domesticated the turkey.
Maize (corn) later became the staple, or basic crop, of the region
About the same time, another agricultural hearth in the Andean highlands of South America began.
Its main crops were beans, tomatoes, and potatoes; They domesticated llamas, alpaca, and guinea pigs.
In East Africa, crops like coffee, olives, peas, and sesame originated around 8000 B.C.E.
Sorghum, a type of grain, was likely domesticated in Ethiopia around 4000 to 3000 B.C.E.
In West Africa, people raised millets and sorghum.
Hearths are distinct from other areas that adopted agriculture through diffusion.
Sometimes it is difficult to know if a region was a hearth itself or if agriculture was introduced.
Shared Characteristics
While ancient hearths have different physical characteristics, they share some features.
Agriculture flourished in these regions because of fertile soil, availability of water, moderate climates, and organizational skills of the residents.
Some areas saw the development of irrigation due to non-uniform rainfall throughout the year.
Many of the societies that developed in these hearths relied on cooperation from members of the community.
It helped ensure success and encouraged settled life, but also pressured farmers to produce high yields.
Good harvests promoted population growth, which supplied more workers.
The Diffusion of Agriculture
Agriculture depends on the land, but like all human activities, it is mobile.
First Global Diffusions
In ancient times, agriculture evolved independently and separately.
People migrated for various reasons including population pressures, different opportunities, or conflict.
These travelers introduced agriculture to new areas by relocation diffusion.
As people migrated, the distribution of their crops and animals expanded.
Through stimulus diffusion, humans adapted the ideas of agriculture to best fit their land.
In some cases, diffusion simply introduced new crops rather than the practice of agriculture itself.
The indigenous peoples of eastern North America already knew how to farm when maize was introduced to the region.
By the 15th century, many domesticated plants and animals had spread throughout Africa, Europe, and Asia.
Other crops and animals had diffused widely between North and South America.
The peoples of the Eastern and Western Hemispheres had minimal contact, which set the stage for the Columbian Exchange.
The Columbian Exchange
Columbian Exchange: The exchange of goods and ideas between the Americas, Europe, and Africa that began after Christopher Columbus landed in the Americas in 1492
It had a huge impact on people, plants, and animals around the world and offers many examples of agricultural diffusion.
Columbus’s arrival directly affected the human population.
Isolation proved disastrous for the indigenous peoples of the Americas, they had no immunities to diseases from the Eastern Hemisphere.
These diseases devastated the Americas’ native populations.
While not considered part of the Columbian Exchange, the global diffusion of throughout the Americas gave rise to new cultures.
In terms of agriculture, the Columbian Exchange had other momentous consequences on both sides of the Atlantic Ocean.
Crops from the Americas like maize and potatoes were incredibly nutritional and were quickly adopted in regions of Europe, Asia, and Africa.
One result was population explosions in Europe and Asia.
Over time, some crops from the Americas dominated the diets of many people in the Eastern Hemisphere
The Columbian Exchange also transformed the Americas, with European crops and animals spreading widely throughout the Western Hemisphere.
Diffusion in Modern Times
Agricultural diffusion continues today.
People have developed a worldwide system of agriculture with global markets and expanding tastes.
Producers seek new consumers for their products year-round.
12.4 Advances in Agriculture
The First Agricultural Revolution
First agricultural revolution: The shift from foraging for food to farming about 11,000 years ago, marking the beginning of agriculture
Remember that this happened independently in several different hearths.
This revolution, although singular, did not happen simultaneously in all regions.
From the points of origin, the first agricultural revolution diffused into other areas as groups of people transitioned from foraging to agriculture.
Some advancements were independently developed, while others may have been borrowed from other hearths.
By some estimates, more than 80 percent of the world’s diet comes from a dozen or so staple crops.
These staples were originally cultivated in the first agricultural revolution.
This revolution also saw the domestication of many livestock animals still raised today.
The first agricultural revolution is sometimes called the Neolithic Revolution because it took place during a time in history now known as the Neolithic Age.
Societal Changes
The first agricultural revolution profoundly changed the lives of the people who experienced it.
Firstly, they went from being nomadic to being sedentary or semisedentary.
This change from constant movement to settling in one place lead people to build more permanent and durable housing.
Living in one area also mean more reliance on one area.
Farming ensured a steadier food supply, but decreased variety in the diet.
Farming practices in agricultural societies improved over time.
Farmers learned to plant seeds from their strongest plants to generate more productive crops.
New tools and practices made farming tasks easier. Domesticated animals were bred to do work, not just provide food.
Increased efficiency meant more food, bolstering the population.
This led to more workers for the farms and surpluses of food.
With everyone’s sustenance ensured, some people could specialize because their labor was not needed.
Instead of food production, they focused on skills such as pottery-making or woodworking.
Eventually, people began to work with metals, and produced stronger tools and weapons or made luxury goods.
In addition, farmers produced some nonfood crops.
Cotton and other fibers were grown for textiles, making clothes, blankets, and other goods.
Sheep and goats were not kept solely for their meat; their wool could be sheared each year.
As societies became more productive, they also became more complex. Larger settlements led to new forms of social organization.
Ruling classes emerged, as certain people took charge of making laws, organizing activities, distribution, and settling disputes.
Food surpluses could become the target of raids by other groups.
There arose a need to defend your society and its resources, creating a fighting class.
Religion also remained in the form of rituals said to ensure good harvest or protection.
Religious elites maintained the elevated status that they generally had within pre-agricultural groups as well.
Population growth meant larger and larger villages, some growing into what can be considered cities.
Nearby settlements traded with one another and with distant communities, gaining access to goods that could not have been obtained locally.
Over time, the first ancient civilizations developed, characterized by large urban centers, complex societies, and advances in knowledge and the arts.
The Second Agricultural Revolution
For the next several millennia, people around the world continued to make breakthroughs that made agriculture more productive.
The ancient Romans were systematic about improvements, taking notes on farming practices they saw in the lands they conquered.
In the 11th century C.E., farmers in southern China planted a faster-growing rice native to Vietnam.
Farmers in northern Europe in the Middle Ages developed a wheeled plow that improved cultivation.
These advances were not as impactful as the Neolithic Revolution, but were still significant.
Second agricultural revolution: A change in farming practices, marked by new tools and techniques, that diffused from Britain and the Low Countries starting in the early 18th century
This revolution saw dramatic improvements in crop yields.
A change in the way farms were organized was a major driver of the revolution.
Previously, agriculture was done by peasants who grew food for themselves on communal land.
This changed as people moved to using individual land.
Enclosure system: A system in which communal lands were replaced by farms owned by individuals, and use of the land was restricted to the owner or tenants who rented the land from the owner
This change gave owners more control over their farms and led to more effective farming practices.
It also pushed peasants off of the land and left many people unemployed, which contributed to the Industrial Revolution.
New tools of this agricultural revolution were invented in the United States, too.
During this revolution, farmers adopted new methods of crop rotation that prevented soil exhaustion and increased yields.
This resulted in another population boom. People now had more food, more nutritious diets, and longer life expectancies.
As more farm work was taken over by machines, laborers had to look for work in other economic areas.
This would provide a ready population to work in the factories that were established in the Industrial Revolution.
This revolution happened alongside advances in transportation. As more food could be transported greater distances, a larger market was created.
The Third Agricultural Revolution
Third agricultural revolution: A shift to further mechanization in agriculture through the development of new technology and advances that began in the early 20th century and continues to the present-day
The first shift was moving from mechanical to electric power, breaking away from animals.
Synthetic fertilizers and pesticides are developed.
This revolution occurred first in core countries, then diffused to peripheral ones.
There are two important tools that were added to improving agriculture in this revolution.
First, advances in scientific understanding allowed scientists to manipulate the genetic makeup of plants and animals.
Genetically modified organisms: A plant or animal with specific characteristics obtained through the manipulation of its genetic makeup
Farmers are more capable of monitoring water and nutrient levels now, allowing for targeted delivery to meet crops’ needs.
Some scientists refer to this use of information technology and data analytics as a fourth agricultural revolution.
This recent period has been characterized by efficiency driven by data.
Productivity Through Technology
The first increase in mechanization took place in the form of motorized tractors.
These multipurpose pieces of equipment had attachments that could be used for plowing, harvesting, and other functions.
Tractors replaced horses, oxen, and other beasts of burden, speeding a farmer’s work and facilitating cultivation of larger plots of land.
Later, further innovations created special, larger machines that were even more effective.
Adopting electricity greatly aided crop storage and preservation and enhanced livestock raising and dairy farming.
Another innovation was the development and widespread use of synthetic fertilizers and pesticides.
The Green Revolution
Green revolution: Movement beginning in the 1950s and 1960s in which scientists used knowledge of genetics to develop new high-yield strains of grain crops
The new crop strains—already in use in the United States—were introduced in areas with low yields and large populations.
Spearheading this movement was Norman Borlaug, an American scientist from Iowa.
A crucial part of his vision of the Green Revolution was to train local agricultural scientists so that they could continue to make advances.
In the early 21st century, several groups began work on spreading the Green Revolution to Africa.
Impact and Response
Although it fed many people and saved lives, the third agricultural revolution did not come without costs.
First, increased mechanization reduced the need for human labor. Agricultural workers became displaced.
When human labor was required, growers came to rely increasingly on migrant workers.
Second, some technology of this revolution is dominated by multinational corporations, leaving producers vulnerable to their marketing and sales practices.
It has also had environmental impacts.
The increase in grown crops demands more water, leaving some areas depleted of it.
Use of synthetic pesticides consisting of powerful chemicals can harm both pests and helpful insects and animals.
The buildup of chemicals can pollute water supplies and cause human health problems.
Larger facilities run by corporations often require large amounts of energy and other natural resources.
The push for monocropping has lead to a decrease in biodiversity.
Many producers have reacted to these drawbacks by investing in alternate approaches to farming.