Fertility can refer to the ability of soil to sustain plant growth, or it can refer to the number of live births occurring in a population.

Fertile Soil

Agronomists, or people who study the uses of plants, use the term to refer to soil. Plants grow easily in fertile soil because it contains large amounts of nutrients. These nutrients, which help keep plants healthy, come from minerals and decaying plant and animal matter. Minerals may have been deposited in the soil during the last glacial period, or Ice Age.

Fertilizers can be added to soil to increase fertility. Fertilizers contain nutrients such as phosphorous, nitrogen, and potassium. Composted plant matter, called humus, is a natural fertilizer that can improve soil fertility. Manure, or the droppings of some animals such as bats or cows, is also an excellent fertilizer. Many companies manufacture fertilizers for use on specific crops. These fertilizers can be applied directly to the soil or to the plants.

Poor farming techniques, certain grazing practices, and erosion can make the soil less fertile. Planting a single crop, year after year, can drain the soil of nutrients. Overgrazing by too many cows, goats, or sheep can prevent new grasses from growing. Erosion allows the soil to either blow away by wind or drain away by water.

Fertile soil is usually found in river basins or in places where glaciers deposited minerals during the last Ice Age. Valleys and plains are usually more fertile than mountains. The Pampas, for example, is an extremely fertile plains region in South America. The Pampas includes parts of Argentina, Brazil, and Uruguay. The Pampas supports both farming and ranching.

Human Fertility

For demographers—people who study population statistics—fertility means the number of live births occurring in a population.

The general fertility rate is the number of live births per 1,000 women of childbearing age (usually ages 15 to 44) in a given year. Governments keep track of the general fertility rate to determine if their population will grow, shrink, or stay the same size. This determines such things as how much food needs to be produced, what sort of public transportation is needed, and how health care is addressed.

Fertility rates tend to be lower in industrialized nations, such as the United States, than in underdeveloped countries. There are many reasons for this. Mothers and children have greater access to health care in industrialized nations. This means children’s mortality rates, or the number of children who die before turning five, are much lower. Women also have greater access to family planning services. The fertility rate in the developed, industrialized nation of South Korea, for instance, is about 1.2. This means that most women have one child. The fertility rate in neighboring North Korea is nearly 2, meaning most women have two children. North Korea is a developing country.

Women in industrialized nations have access to more education and professional development. Many women choose to go to school or get a job instead of having children at a young age. Many choose not to have children at all. This lowers the fertility rate in industrialized nations.

Industrialized nations usually have a school system for young children. In developing nations, young children may work to support their families instead of going to school. The fertility rate may rise because more children means more workers. In industrialized nations, children are not expected to take care of their parents and grandparents.

The tendency for industrialized nations to have lower birth rates is not always true. The United States has the highest birth rate of all industrialized nations, at about 2. This is far higher than developing nations such as Uruguay (1.9), Tunisia (1.7) or Thailand (1.6).

In order to maintain a stable population, each woman must bear two children—one to replace each parent. High fertility rates—where most women give birth to more than two healthy babies—can lead to overpopulation. Low fertility rates—where most women give birth to one child or no children—can lead to a dwindling population.

Some nations want to increase their fertility rate. Japan has one of the lowest fertility rates in the world. The general fertility rate hit a record low of 1.21 in 2009, even though the Japanese government made efforts to encourage women to have children. The country's population is declining and the average age is getting older.

Some want to decrease their fertility rate. China’s famous “one child policy” is a good example of this. China is the most populous country in the world. The Chinese government believes that lowering the fertility rate would increase the resources, such as education and jobs, available to its citizens. In the late 1970s, China set taxes and economic fines for families with more than one child. (The fines and taxes do not apply to ethnic minorities and other groups, such as rural farm families.) As a result, the fertility rate in China has dropped. China now has a lower fertility rate than the United States.

Fourteen countries have fertility rates with at least six children per woman. These countries are Afghanistan, Angola, Burkina Faso, Burundi, Chad, the Democratic Republic of the Congo, Guinea-Bissau, Liberia, Mali, Niger, Sierra Leone, Somalia, Timor Leste, and Uganda.

Fertility does not always correspond to population. Despite their high fertility rates, the countries listed above make up less than five percent of the world’s population. Countries with much larger populations, such as India, China, and the United States, have lower fertility rates.

fertility
Coatlicue is the chief fertility goddess in the Aztec culture.

Fertile Crescent
The Fertile Crescent is an area in the Middle East where many aspects of civilization, including agriculture and writing, were first practiced. The region stretches in an arc from the modern-day countries of Iraq and Kuwait on the Persian Gulf, up to the southern part of Turkey, down along the Mediterranean coast of Jordan and Israel, and ending in northern Egypt. The soil of the Fertile Crescent is extremely fertile, which allowed agricultural communities, and eventually cities and civilization, to develop.

Fertility Gods
Soil fertility and human fertility were both extremely important to ancient people. Almost every ancient culture had a deity associated with fertility. The deity was worshipped and offered sacrifices in order to ensure a healthy crop and healthy children. Fertility deities can be gods, such as Kokopelli, the fertility deity of many cultures of the American Southwest. Fertility deities can also be goddesses, such as Hathor, who was worshipped in Egypt.

agronomist
Noun

person who studies soil and its role in agriculture.

childbearing age
Noun

age at which a female can give birth to offspring.

compost
Noun

mixture of decaying organic material, such as food waste and plants.

correspond
Verb

to match or be similar to.

Noun

agricultural produce.

decay
Verb

to rot or decompose.

deity
Noun

very holy or spiritual being.

demographer
Noun

person who studies patterns in human populations.

deposit
Verb

to place or deliver an item in a different area than it originated.

drain
Verb

to empty.

dwindle
Verb

to shrink.

encourage
Verb

to inspire or support a person or idea.

ensure
Verb

to guarantee.

Noun

act in which earth is worn away, often by water, wind, or ice.

farming
Noun

the art, science, and business of cultivating the land for growing crops.

Noun

capacity of soil to sustain plant growth; or the average number of children born to women in a given population.

fertilizer
Noun

nutrient-rich chemical substance (natural or manmade) applied to soil to encourage plant growth.

general fertility rate
Noun

number of live births per 1,000 women of childbearing age.

glacial period
Noun

time of long-term lowering of temperatures on Earth. Also known as an ice age.

Noun

mass of ice that moves slowly over land.

government
Noun

system or order of a nation, state, or other political unit.

grass
Noun

type of plant with narrow leaves.

graze
Verb

to feed on grass, usually over a wide pasture.

Hathor
Noun

fertility goddess of ancient Egypt.

health care
Noun

system for addressing the physical health of a population.

Noun

material that forms when plant and animal matter decays.

Ice Age
Noun

last glacial period, which peaked about 20,000 years ago.

industrial
Adjective

having to do with factories or mechanical production.

Kokopelli
Noun

fertility god of the ancient North American southwest.

manure
Noun

animal excrement or waste used to fertilize soil.

mineral
Noun

inorganic material that has a characteristic chemical composition and specific crystal structure.

mortality rate
Noun

the ratio of the total number of deaths to the total population in a given time and area. Also called the death rate.

mountain
Noun

landmass that forms as tectonic plates interact with each other.

nitrogen
Noun

chemical element with the symbol N, whose gas form is 78% of the Earth's atmosphere.

Noun

substance an organism needs for energy, growth, and life.

overpopulation
Noun

situation where the amount of organisms in an area is too large for the ecosystem to support.

Pampas
Noun

flat grasslands of South America.

phosphorus
Noun

chemical element with the symbol P.

Noun

flat, smooth area at a low elevation.

population
Noun

total number of people or organisms in a particular area.

population statistics
Noun

patterns in populations of organisms.

potassium
Noun

chemical element with the symbol K.

professional development
Noun

opportunities to improve in a career.

public transportation
Noun

methods of movement that are available to all community members for a fee, and which follow a fixed route and schedule: buses, subways, trains and ferries.

ranch
Noun

large farm on which livestock are raised.

sacrifice
Noun

destruction or surrender of something as way of honoring or showing thanks.

soil
Noun

top layer of the Earth's surface where plants can grow.

sustain
Verb

to support.

underdeveloped country
Noun

country that has fallen behind on goals of industrialization, infrastructure, and income.

valley
Noun

depression in the Earth between hills.