ARTICLE ON AGRICULTURE

Agriculture is the art and science of cultivating the soil, growing crops, and raising livestock. It includes the preparation of plant and animal products for people to use and their distribution to markets.

Agriculture provides most of the world’s food and fabrics. Cotton, wool, and leather are all agricultural products. Agriculture also provides wood for construction and paper products.

These products, as well as the agricultural methods used, may vary from one part of the world to another.

Start of Agriculture

Over centuries, the growth of agriculture supported the development of cities. Before agriculture became widespread, hunting and gathering was how people fed themselves. Between 10,000 and 12,000 years ago, people gradually learned how to grow cereal and root crops, and settled down to a life based on farming.

Eventually, much of Earth’s population became dependent on agriculture. Scholars are not sure why this shift to farming took place, but it may have occurred because of climate change.

When people began growing crops, they also continued to adapt animals and plants for human use. Adapting wild plants and animals for people to use is called domestication. Hunter-gatherers began to domesticate animals and change the natural environment to grow more food even before settled farming became widespread.

Barley, wheat, legumes, vetch, and flax were among the first plants to be domesticated.

The first domesticated animals were dogs, which were used for hunting. Sheep and goats were probably domesticated next. People also domesticated cattle and pigs. The predecessors of most of these animals had once been hunted for hides and meat. Many of them also became sources of milk, cheese, and butter. Eventually, people used domesticated animals such as oxen for plowing, pulling, and transportation.

Agriculture enabled people to produce surplus food. They could use this extra food when crops failed or trade it for other goods.

Agriculture kept formerly nomadic people near their fields and led to the development of permanent villages. These became linked through trade. New economies were so successful in some areas that cities developed. The earliest societies based on intensive agriculture arose in the Fertile Crescent (which spans the Levant, modern-day Turkey, and Iran) and along the Nile River in Egypt. Other very early agricultural societies developed independently in Central America, East Asia, the Indus Valley, and West Africa.

Improved Technology

Many effective agricultural techniques have roots in pre-agricultural human history. For millennia, people have used controlled burning techniques to get rid of brush and debris, allowing edible plants to grow more abundantly and preventing larger wildfires during dry seasons. Today, large wildfires in North America and Australia demonstrate the importance of maintaining controlled burning practices perfected by many Native American tribes and Aboriginal Australian peoples.

Farming has also improved over the years. Early farmers cultivated small plots of land by hand, using axes to clear away trees and digging sticks to break up and till the soil. Over time, improved farming tools of bone, stone, bronze, and iron were developed. New methods of storage evolved. People began stockpiling foods in jars and clay-lined pits for use in times of scarcity. They also began making clay pots and other vessels for carrying and cooking food.

Around 5500 B.C.E., farmers in Mesopotamia developed simple irrigation systems. By channeling water from streams onto their fields, farmers were able to settle in areas once thought to be unsuited to agriculture. In Mesopotamia, Egypt, and China, people organized themselves and worked together to build and maintain better irrigation systems.

Early farmers also developed improved varieties of plants. For example, around 6000 B.C.E., a new variety of wheat arose in South Asia and Egypt. It was stronger than previous cereal grains, its hulls were easier to remove, and it could be made into bread.

As the Romans expanded their empire using warfare and coercion, they wrote manuals about the farming techniques they observed in Africa and Asia, and adapted them to land in Europe.

In China, farmers also adapted tools and methods from nearby empires. A variety of rice from Vietnam ripened quickly and allowed farmers to harvest several crops during a single growing season. This rice quickly became popular throughout China.

Many medieval European farmers used an open-field system of planting. One field would be planted in spring, another in autumn, and one would be left unplanted, or fallow. This system preserved nutrients in the soil, increasing crop production.

The leaders of the Islamic Golden Age (which reached its height around 1000 C.E.) in North Africa and the Middle East made agriculture into a science. Islamic Golden Age farmers learned crop rotation.

In the 15th and 16th centuries, explorers introduced new varieties of plants and agricultural products into Europe. From Asia, they carried home coffee, tea, and indigo, a plant used to make blue dye. From the Americas, they took plants such as potatoes, tomatoes, corn (maize), beans, peanuts, and tobacco. Some of these became staples and expanded people’s diets.

Machinery

A period of important agricultural development began in the early 1700s for Great Britain and the Low Countries (Belgium, Luxembourg, and the Netherlands, which lie below sea level). New agricultural inventions dramatically increased food production in Europe and European colonies, particularly in North America.

One of the most important of these developments was an improved horse-drawn seed drill invented by Jethro Tull in England. Until that time, farmers sowed seeds by hand. Tull’s drill made rows of holes for the seeds. By the end of the 18th century, seed drilling was widely practiced in Europe.

Many machines were developed in the United States. The cotton gin, invented by Eli Whitney in 1794, reduced the time needed to separate cotton fiber from seed. The invention of the cotton gin was not without negative consequences, however: as cotton became more profitable and less labor-intensive, enslavers had incentive to buy more enslaved people to produce more cotton.

In the 1830s, Cyrus McCormick’s mechanical reaper helped modernize the grain-cutting process. At about the same time, John and Hiram Pitts introduced a horse-powered thresher that shortened the process of separating grain and seed from chaff and straw. John Deere’s steel plow, introduced in 1837, made it possible to work the tough prairie soil with much less horsepower. Along with new machines, there were several important advances in farming methods. By selectively breeding animals (breeding those with desirable traits), farmers increased the size and productivity of their livestock.

Cultures have been breeding animals for centuries. Ancestors of modern sheep, goats, cattle, and pigs were the first livestock to be bred selectively. Farmers began to practice selective breeding on a large scale beginning in 18th century Europe. An early example of this is the Leicester sheep, an animal selectively bred in England for its quality meat and long, coarse wool.

Plants could also be selectively bred for certain qualities. In 1866, Gregor Mendel’s studies in heredity were published in Austria. In experiments with pea plants, Mendel learned how traits were passed from one generation to the next. His work paved the way for improving crops through genetics.

New crop rotation methods also evolved during this time. Many of these were adopted over the next century or so throughout Europe. For example, the Norfolk four-field system, developed in England, proved quite successful. It involved the yearly rotation of several crops, including wheat, turnips, barley, clover, and ryegrass, and livestock management practices, in which animals grazed in selected fields and left animal waste behind. This added nutrients to the soil, enabling farmers to grow enough to sell some of their harvest without having to leave any land unplanted.

Agricultural Science

Between 1960 and 2000, staple crop yields in low- and middle-income countries like Mexico and India increased substantially. How did this great leap in productivity come about? It happened largely because of scientific advances and the development of new sources of power.

By the late 1950s, most farmers in high-income countries were using both gasoline and electricity to power machinery. Tractors had replaced draft animals and steam-powered machinery. Farmers were using machines in almost every stage of cultivation and livestock management.

Electricity first became a power source on farms in Japan and Germany in the early 1900s. By 1960, most farms in the U.S. and other high-income countries were electrified. Electricity lit farm buildings and powered such machinery as water pumps, milking machines, and feeding equipment. Today, electricity controls entire environments in livestock barns and poultry houses.

Traditionally, farmers have used a variety of methods to protect their crops from pests and diseases. They have put herb-based poisons on crops, handpicked insects off plants, bred strong varieties of crops, and rotated crops to control insects. Now, almost all farmers, especially in high-income countries, rely on chemicals to control pests. The definition of “pest” ranges from insects to animals such as rabbits and mice, as well as weeds and disease-causing organisms—bacteria, viruses, and fungi. With the use of chemicals, crop losses and prices have declined dramatically.

For thousands of years, farmers relied on natural fertilizer—materials such as manure, wood ash, ground bones, fish or fish parts, and bird and bat waste called guano—to replenish or increase nutrients in the soil. Some farmers, particularly those that grow organic crops, still use natural fertilizers.

In the early 1800s, scientists discovered which elements were most essential to plant growth: nitrogen, phosphorus, and potassium. Now, many farmers use chemical fertilizers with nitrates and phosphates because they greatly increase crop yields.

However, pesticides and fertilizers have come with another set of problems. The heavy reliance on chemicals has disturbed the environment, often contaminating the surrounding soil and water while being toxic to birds, fish, and other species that farmers do not intend to target. Chemical use may also pose a health hazard to people, especially through contaminated water supplies. Agricultural scientists are looking for safer chemicals to use as fertilizers and pesticides. Some farmers use natural controls and rely less on chemicals.

Farming in Water

Agriculture includes such forms of cultivation as hydroponics and aquaculture. Both involve farming in water.

Hydroponics is the science of growing plants in nutrient solutions. Just one acre of nutrient solution can yield more than 50 times the amount of lettuce grown on the same amount of soil.

Aquaculture—primarily the cultivation of fish and shellfish—was practiced in China, India, and Egypt thousands of years ago. It is now used in lakes, ponds, the ocean, and other bodies of water throughout the world. Some forms of aquaculture, such as shrimp farming, have become important industries in many Asian and Latin American countries.

Climate change and improved technology are altering the way freshwater and ocean fisheries operate. Global warming has pushed warm-water species toward the poles and reduced the habitats of cold-water species. Traditional fishing communities in both developed and developing countries find the number of fish dwindling.

Bottom trawling has affected ocean ecosystems. In bottom trawling, enormous nets are strung from fishing boats and dragged at the bottom of the ocean. The nets catch halibut and squid, but also stir up sediment at the bottom of the ocean. This disturbs the marine life (plankton and algae) that forms the basis of the food chain.