The word "fertility" can refer to many forms of life. Plants grow better in soil that is fertile. A fertile population is one that has, or can have, many kids. The main idea behind fertility is being able to make life.

Fertile Soil

Plants grow easily in fertile soil because it contains large amounts of nutrients. These nutrients help keep plants healthy.

Fertilizers can be added to soil to increase fertility. Fertilizers contain nutrients such as phosphorous, nitrogen, and potassium. Many fertilizers are made in labs, but others are found in nature. Composted plant matter, called humus, is a natural fertilizer. Manure, or the droppings of animals such as bats or cows, is also an excellent fertilizer.

Many companies make fertilizers to help specific crops grow. These fertilizers can be applied directly to the soil or to the plants.

Poor farming methods can make the soil less fertile. For example, planting a single crop, year after year, can drain the soil of nutrients. Another example is overgrazing, when cows, goats, or sheep graze too much grass. This often prevents new grass from growing. Erosion also hurts crops. Erosion is when the soil gets blown away by wind or drained away by water.

Fertile soil is usually found near rivers or in places where glaciers left behind certain minerals. These minerals were deposited during the last Ice Age, which ended more than 11,000 years ago. Valleys and plains are usually more fertile than mountains.

Human Fertility

Fertility also applies to people and animals. Demographers are experts who study the numbers and changes of a certain population. For a demographer, fertility means the number of live births in a group of people.

The general fertility rate is a number that shows how fertile a population is. It is calculated as the number of live births in one year for every 1,000 women. Only birthing people who are 15 to 44 years old are considered. That is when most women can have children.

Governments keep track of the general fertility rate. They want to know if their population will grow, shrink, or stay the same. This information shows governments how much food or healthcare people will need.

Fertility Rates Can Vary in Different Countries

The fertility rate in the wealthy 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 two, meaning most women have two children. North Korea is a poorer country.

Fertility rates tend to be lower in wealthy nations, such as the United States. There are many reasons for this. Mothers in wealthy nations have greater access to family planning services. They have more control over when to have children.

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

Wealthier nations usually have a school system for young children. In poorer 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.

U.S. has Highest Birth Rate of Wealthy Nations

Not all wealthy nations have lower birth rates. The United States has the highest birth rate of all wealthy, industrialized nations. Its birth rate is about two children per person.

In order for a population to stay at the same level, each woman must have two children. That means one to replace each parent. When most women give birth to more than two healthy babies, a country's population can grow. This is known as a population boom. A country with low fertility can have a decreasing population.

Some countries want to increase their fertility rate. Japan is one example. The country's population is getting smaller. Its people are getting older and older.

China's Low Fertility Rate

Other countries want to decrease their fertility rate. China is a good example of this. China has the most people of any country. The Chinese government believes that lowering the fertility rate would allow more citizens to get an education, jobs, and other resources.

In the late 1970s, China set taxes and fines for families with more than one child. As a result, the fertility rate in China has dropped. China now has a lower fertility rate than the United States. China now allows families to have two children.

Fourteen countries have fertility rates with at least six children per woman. Although the numbers are high, these countries 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.