Agriculture

Agriculture is the practice of growing plants and raising animals to provide food and other useful products. It includes planting crops, raising livestock, and even growing forests and raising fish. Agriculture helped people move from small groups to living in big cities because it produced more food than people needed.

Humans began gathering wild grains over 100,000 years ago, but farming began around 11,500 years ago. Since then, people have raised animals like sheep, goats, pigs, and cattle, and grown crops in many parts of the world. Today, both small farms and very large farms play important roles in feeding the world.

Farms provide many things we use every day, such as food like grains, vegetables, fruits, meat, milk, and eggs. They also give us materials like wood, fibers for clothes, and fuels. However, farming can also affect the environment, and it is important to balance growing food with protecting nature.

Etymology and scope

Further information: Horticulture § Scope

The word agriculture comes from old Latin words for "field" and "growing." It means using natural resources to grow things that help us live, like food, clothes from plants, and products from forests. This wide meaning includes growing crops, raising animals, and taking care of forests, though sometimes forests are thought of separately. We can split agriculture into two parts: growing plants and raising animals.

Interestingly, some animals like ants, termites, and beetles have been growing crops for as long as 60 million years!

History

Main article: History of agriculture

Origins

Main article: Neolithic Revolution

Farming changed how people lived. It let more people live in one place because they had steady food from plants and animals they raised. Farming started in many places around the world. People began to grow grains like wheat and rice thousands of years ago. They also raised animals such as sheep and pigs. Over time, many different plants and animals were domesticated to help feed growing communities.

Civilizations

Early villages in places like Mesopotamia used rivers to water their fields. They grew crops like wheat and barley. In Egypt, the Nile River helped farmers grow food each year when it flooded. In India, people grew wheat and raised animals like sheep. China had systems to store food and grow silk. In the Americas, people grew crops like maize and potatoes. Different places developed their own ways to farm using what grew well around them.

In the Americas, people grew crops such as squash, beans, and cacao. The Aztecs built systems to bring water to their fields. In South America, people grew crops like potatoes and coca. In North America, native people grew sunflowers and tobacco. They also used techniques like controlled burning to help their crops grow.

During the Middle Ages in Europe, farming focused on feeding local areas. New crops and better farming methods came from places like Al-Andalus. After new lands were discovered, crops from different parts of the world were shared. Better farming tools and ways to add nutrients to soil helped more food be grown, supporting larger populations.

Types

See also: Staple food

Pastoralism is about taking care of animals. In nomadic pastoralism, animal herds travel to find fresh grass, food, and water. This kind of farming happens in dry places like the Sahara, Central Asia, and parts of India.

In shifting cultivation, a small forest area is cleared to grow crops for a few years until the soil gets tired, then a new spot is used. This happens in rainy areas where forests grow back fast, like in Northeast India, Southeast Asia, and the Amazon Basin.

Subsistence farming is when families grow food just for themselves, with little extra to share. Many people do this in Monsoon Asia and South-East Asia. About 2.5 billion such farmers worked in 2018, using around 60% of the world's arable land.

Intensive farming focuses on getting as much food as possible by using lots of water, fertilizers, and machines. This is common in wealthy countries.

Contemporary agriculture

From the twentieth century onwards, farming methods changed to increase how much food could be grown. These changes used special fertilizers and chemicals instead of as much human labor, but they also caused problems like pollution of water. Soil damage and plant diseases are big worries today, with about 40% of the world’s farmland suffering from damage. Modern farming faces many challenges, such as protecting water supplies, dealing with new plant diseases, and making choices about using special plant types that are changed in a laboratory. Some people have gone back to older, more natural ways of farming, like organic farming, because they are worried about the effects of regular farming on the environment. Big farms in places like North America caused a lot of dust and damage in the 1930s, known as the Dust Bowl. Recently, more people have started to care about how farming affects the environment, leading to movements for organic, sustainable, and better farming practices. The European Union has been a big part of this change, helping farms grow food without harming the land as much. New technologies are being tested, like better ways to control pests and growing plants in controlled spaces. There are worries that organic farming might not produce as much food, which could affect how enough food is available for everyone.

Between 1964 and 2023, most growth in farming came from using better methods, not from using more land. In the twenty-first century, the total area used for farming went down by 2%, but the land used to grow crops went up while the land used for grazing animals went down. This change happened differently in various parts of the world. In Sub-Saharan Africa, more land was used for crops and forests were lost, while in Latin America, crops took over land and forests were lost too. Farming is a big reason why forests disappear around the world, causing about 90% of forest loss. Every year, about 3.6 million hectares of cropland are left unused, possibly because the land is damaged. By 2015, China grew the most food, followed by the European Union, India, and the United States. In the United States, farming is much more productive now than it was in 1948.

Farming provides jobs for many people. In 2021, it employed 873 million people, which is 27% of all jobs worldwide. Even though the number went up to 916 million in 2023, it was lower than the 1 billion people in the year 2000. Still, many people, especially in poorer countries, work in farming. Even with more machines and technology, farming still needs many workers, and in some places, most people work on farms.

Women play an important role in farming around the world. In many developing countries, women make up a large part of farm workers. They often face challenges, like having less access to tools, land, and money compared to men. Women in farming usually work in harder conditions and get paid less. However, there is some good news: women are catching up in using mobile internet and bank services, which can help them in farming. When women have the same chances as men, they can use new tools and technologies just as well.

Farming can be dangerous. Farmers often face risks like injuries from machines, health problems from chemicals, and diseases from working outdoors. On big farms, accidents with machines like tractors are common causes of serious injuries. Chemicals used on farms can harm both workers and their families, who might also live on the farm. Young children on farms can be especially at risk, with dangers like drowning or accidents with vehicles. Even though farming can be risky, there are also benefits for children growing up on a farm.

Farming affects the environment in many ways. It uses a lot of land and water, which can hurt natural resources. Farming is a big reason why forests are cut down and why areas with lots of carbon, like peatlands, are damaged. Many farms use chemicals that can hurt wildlife and soil. Farming also uses most of the world’s fresh water, and this use is expected to grow. As water becomes harder to find, this can affect how much food can be grown.

Production

Main article: List of countries by GDP sector composition

See also: List of most important agricultural crops worldwide

Overall production varies by country as listed.

Crop cultivation systems

Cropping systems vary among farms depending on the available resources and constraints; geography and climate of the farm; government policy; economic, social and political pressures; and the philosophy and culture of the farmer.

Shifting cultivation (or slash and burn) is a system in which forests are burnt, releasing nutrients to support cultivation of annual and then perennial crops for a period of several years. Then the plot is left fallow to regrow forest, and the farmer moves to a new plot, returning after many more years (10–20). This fallow period is shortened if population density grows, requiring the input of nutrients (fertilizer or manure) and some manual pest control. Annual cultivation is the next phase of intensity in which there is no fallow period. This requires even greater nutrient and pest control inputs.

Further industrialization led to the use of monocultures, when one cultivar is planted on a large acreage. Because of the low biodiversity, nutrient use is uniform and pests tend to build up, necessitating the greater use of pesticides and fertilizers. Multiple cropping, in which several crops are grown sequentially in one year, and intercropping, when several crops are grown at the same time, are other kinds of annual cropping systems known as polycultures.

In subtropical and arid environments, the timing and extent of agriculture may be limited by rainfall, either not allowing multiple annual crops in a year, or requiring irrigation. In all of these environments perennial crops are grown (coffee, chocolate) and systems are practiced such as agroforestry. In temperate environments, where ecosystems were predominantly grassland or prairie, highly productive annual farming is the dominant agricultural system.

Important categories of food crops include cereals, legumes, forage, fruits and vegetables. Natural fibers include cotton, wool, hemp, silk and flax. Specific crops are cultivated in distinct growing regions throughout the world. Production is listed in millions of metric tons, based on FAO estimates.

Livestock production systems

Main articles: Livestock and Animal husbandry

See also: List of domesticated animals

Animal husbandry is the breeding and raising of animals for meat, milk, eggs, or wool, and for work and transport. Working animals, including horses, mules, oxen, water buffalo, camels, llamas, alpacas, donkeys, and dogs, have for centuries been used to help cultivate fields, harvest crops, wrangle other animals, and transport farm products to buyers.

Livestock production systems can be defined based on feed source, as grassland-based, mixed, and landless. As of 2010^[update], 30% of Earth's ice- and water-free area was used for producing livestock, with the sector employing approximately 1.3 billion people. Between the 1960s and the 2000s, there was a significant increase in livestock production, both by numbers and by carcass weight, especially among beef, pigs and chickens, the latter of which had production increased by almost a factor of 10. Non-meat animals, such as milk cows and egg-producing chickens, also showed significant production increases. Global cattle, sheep and goat populations are expected to continue to increase sharply through 2050. Aquaculture or fish farming, the production of fish for human consumption in confined operations, is one of the fastest growing sectors of food production, growing at an average of 9% a year between 1975 and 2007.

During the second half of the 20th century, producers using selective breeding focused on creating livestock breeds and crossbreeds that increased production, while mostly disregarding the need to preserve genetic diversity. This trend has led to a significant decrease in genetic diversity and resources among livestock breeds, leading to a corresponding decrease in disease resistance and local adaptations previously found among traditional breeds.

Grassland based livestock production relies upon plant material such as shrubland, rangeland, and pastures for feeding ruminant animals. Outside nutrient inputs may be used, however manure is returned directly to the grassland as a major nutrient source. This system is particularly important in areas where crop production is not feasible because of climate or soil, representing 30–40 million pastoralists. Mixed production systems use grassland, fodder crops and grain feed crops as feed for ruminant and monogastric (one stomach; mainly chickens and pigs) livestock. Manure is typically recycled in mixed systems as a fertilizer for crops.

Landless systems rely upon feed from outside the farm, representing the de-linking of crop and livestock production found more prevalently in Organization for Economic Co-operation and Development member countries. Synthetic fertilizers are more heavily relied upon for crop production and manure use becomes a challenge as well as a source for pollution. Industrialized countries use these operations to produce much of the global supplies of poultry and pork. Scientists estimate that 75% of the growth in livestock production between 2003 and 2030 will be in confined animal feeding operations, sometimes called factory farming. Much of this growth is happening in developing countries in Asia, with much smaller amounts of growth in Africa. Some of the practices used in commercial livestock production, including the usage of growth hormones, are controversial.

Production practices

Further information: Tillage, Crop rotation, and Irrigation

Tillage is the practice of breaking up the soil with tools such as the plow or harrow to prepare for planting, for nutrient incorporation, or for pest control. Tillage varies in intensity from conventional to no-till. It can improve productivity by warming the soil, incorporating fertilizer and controlling weeds, but also renders soil more prone to erosion, triggers the decomposition of organic matter releasing CO₂, and reduces the abundance and diversity of soil organisms.

Pest control includes the management of weeds, insects, mites, and diseases. Chemical (pesticides), biological (biocontrol), mechanical (tillage), and cultural practices are used. Cultural practices include crop rotation, culling, cover crops, intercropping, composting, avoidance, and resistance. Integrated pest management attempts to use all of these methods to keep pest populations below the number which would cause economic loss, and recommends pesticides as a last resort.

Nutrient management includes both the source of nutrient inputs for crop and livestock production, and the method of use of manure produced by livestock. Nutrient inputs can be chemical inorganic fertilizers, manure, green manure, compost and minerals. Crop nutrient use may also be managed using cultural techniques such as crop rotation or a fallow period. Manure is used either by holding livestock where the feed crop is growing, such as in managed intensive rotational grazing, or by spreading either dry or liquid formulations of manure on cropland or pastures.

Water management is needed where rainfall is insufficient or variable, which occurs to some degree in most regions of the world. Some farmers use irrigation to supplement rainfall. In other areas such as the Great Plains in the US and Canada, farmers use a fallow year to conserve soil moisture for the following year. Recent technological innovations in precision agriculture allow for water status monitoring and automate water usage, leading to more efficient management. Agriculture represents 70% of freshwater use worldwide. However, water withdrawal ratios for agriculture vary significantly by income level. In least developed countries and landlocked developing countries, water withdrawal ratios for agriculture are as high as 90 percent of total water withdrawals and about 60 percent in Small Island Developing States.

According to 2014 report by the International Food Policy Research Institute, agricultural technologies will have the greatest impact on food production if adopted in combination with each other. Using a model that assessed how eleven technologies could impact agricultural productivity, food security and trade by 2050, the International Food Policy Research Institute found that the number of people at risk from hunger could be reduced by as much as 40% and food prices could be reduced by almost half.

Payment for ecosystem services is a method of providing additional incentives to encourage farmers to conserve some aspects of the environment. Measures might include paying for reforestation upstream of a city, to improve the supply of fresh water.

Agricultural automation

Different definitions exist for agricultural automation and for the variety of tools and technologies that are used to automate production. One view is that agricultural automation refers to autonomous navigation by robots without human intervention. Alternatively, it is defined as the accomplishment of production tasks through mobile, autonomous, decision-making, mechatronic devices. However, FAO finds that these definitions do not capture all the aspects and forms of automation, such as robotic milking machines that are static, most motorized machinery that automates the performing of agricultural operations, and digital tools (e.g., sensors) that automate only diagnosis. FAO defines agricultural automation as the use of machinery and equipment in agricultural operations to improve their diagnosis, decision-making or performing, reducing the drudgery of agricultural work or improving the timeliness, and potentially the precision, of agricultural operations.

The technological evolution in agriculture has involved a progressive move from manual tools to animal traction, to motorized mechanization, to digital equipment and finally, to robotics with artificial intelligence (AI). Motorized mechanization using engine power automates the performance of agricultural operations such as ploughing and milking. With digital automation technologies, it also becomes possible to automate diagnosis and decision-making of agricultural operations. For example, autonomous crop robots can harvest and seed crops, while drones can gather information to help automate input application. Precision agriculture often employs such automation technologies. Motorized machines are increasingly complemented, or even superseded, by new digital equipment that automates diagnosis and decision-making. A conventional tractor, for example, can be converted into an automated vehicle allowing it to sow a field autonomously.

Motorized mechanization has increased significantly across the world in recent years, although reliable global data with broad country coverage exist only for tractors and only up to 2009. Sub-Saharan Africa is the only region where the adoption of motorized mechanization has stalled over the past decades.

Automation technologies are increasingly used for managing livestock, though evidence on adoption is lacking. Global automatic milking system sales have increased over recent years, but adoption is likely mostly in Northern Europe, and likely almost absent in low- and middle-income countries. Automated feeding machines for both cows and poultry also exist, but data and evidence regarding their adoption trends and drivers is likewise scarce.

Measuring the overall employment impacts of agricultural automation is difficult because it requires large amounts of data tracking all the transformations and the associated reallocation of workers both upstream and downstream. While automation technologies reduce labor needs for the newly automated tasks, they also generate new labor demand for other tasks, such as equipment maintenance and operation. Agricultural automation can also stimulate employment by allowing producers to expand production and by creating other agrifood systems jobs. This is especially true when it happens in context of rising scarcity of rural labor, as is the case in high-income countries and many middle-income countries. On the other hand, if forcedly promoted, for example through government subsidies in contexts of abundant rural labor, it can lead to labor displacement and falling or stagnant wages, particularly affecting poor and low-skilled workers.

Effects of climate change on yields

Main article: Effects of climate change on agriculture

Climate change and agriculture are interrelated on a global scale. Climate change affects agriculture through changes in average temperatures, rainfall, and weather extremes (like storms and heat waves); changes in pests and diseases; changes in atmospheric carbon dioxide and ground-level ozone concentrations; changes in the nutritional quality of some foods; and changes in sea level. Global warming is already affecting agriculture, with effects unevenly distributed across the world.

In a 2022 report, the Intergovernmental Panel on Climate Change describes how human-induced warming has slowed growth of agricultural productivity over the past 50 years in mid and low latitudes. Methane emissions have negatively impacted crop yields by increasing temperatures and surface ozone concentrations. Warming is also negatively affecting crop and grassland quality and harvest stability. Ocean warming has decreased sustainable yields of some wild fish populations while ocean acidification and warming have already affected farmed aquatic species. Climate change will probably increase the risk of food insecurity for some vulnerable groups, such as the poor.

Future predictions

In order to meet the demands of a growing global population, agriculture needs to produce about 50% more food, feed and fibre by 2050 compared with the volumes it generated in 2012, according to estimates by the Food and Agriculture Organization of the United Nations (FAO). Achieving such objectives will place additional pressure on the world’s already overstretched water, land and soil resources. In an increasing number of regions, food security and agrifood systems are at risk from unsustainable natural resource management practices, urban expansion, higher demand for food, water, energy and biomaterials, and persisting social and gender inequalities in access to and governance of resources.

Largest countries by agricultural output (in nominal terms) according to IMF and CIA World Factbook, at peak level as of 2018

Economy Countries by agricultural output (in nominal terms) at peak level as of 2018 (billions in USD (01)  China 1,117 (02)  India 414 (—)  European Union 308 (03)  United States 185 (04)  Brazil 162 (05)  Indonesia 141 (06)  Nigeria 123 (07)  Russia 108 (08)  Pakistan 76 (09)  Argentina 70 (10)  Turkey 64 (11)  Japan 62 (12)  France 59 (13)  Iran 57 (14)  Australia 56 (15)  Mexico 51 (16)  Italy 50 (17)  Spain 43 (18)  Bangladesh 41 (19)  Thailand 40 (20)  Egypt 40 The twenty largest countries by agricultural output (in nominal terms) at peak level as of 2018, according to the IMF and CIA World Factbook.

Largest countries by agricultural output according to UNCTAD at 2005 constant prices and exchange rates, 2015
Economy Countries by agricultural output in 2015 (millions in 2005 constant USD and exchange rates) (01)  China 418,455 (02)  India 196,592 (03)  United States 149,023 (04)  Nigeria 77,113 (05)  Brazil 59,977

Crop alteration and biotechnology

Plant breeding

Main article: Plant breeding

Crop alteration has been done by people for thousands of years. By changing crops through breeding, we can make plants better for us, like bigger fruits or seeds, or plants that can survive with less water or fight off pests. Big steps in plant breeding happened after the work of Gregor Mendel. His studies helped us understand how plants pass on their traits.

Breeding plants has made them produce more, resist diseases better, and taste better. Careful choosing and breeding plants changed them a lot. For example, in the 1920s and 1930s, plant breeding improved grasses and clover in New Zealand. In the 1950s, new ways to change plants created modern types of grains like wheat and corn.

The Green Revolution helped grow more food by creating plants that could produce much more. For example, corn yields in the US went from about 2.5 tons per hectare in 1900 to about 9.4 tons per hectare in 2001. Wheat yields around the world also increased a lot.

It takes a long time for new farming ideas to be used everywhere. For example, it took over 60 years for a special type of corn to become common.

Genetic engineering

Main article: Genetic engineering

See also: Genetically modified food, Genetically modified crops, Regulation of the release of genetic modified organisms, and Genetically modified food controversies

Genetically modified organisms (GMO) are plants or animals whose genes have been changed in a lab. This lets farmers create crops that are stronger, have more nutrients, resist insects, or can survive herbicides. Some people worry about eating GMO foods, and many countries have rules about growing or selling them.

Some GMO seeds can survive herbicides, so farmers can spray weeds without harming their crops. But in some places, weeds have learned to survive these sprays, so farmers use other ways to control weeds. Some GMO crops also fight off insects by using a natural toxin from a bacteria.

Environmental impact

Main article: Environmental issues with agriculture

Agriculture affects the environment in many ways. It can harm nature and also suffer from environmental problems. Farming can lead to loss of plants and animals, damage to soil, and changes in climate. It is a big part of why we have problems like climate change and water shortages.

Farming also uses a lot of resources. It takes up space, uses water, and can pollute with chemicals. Animals raised for food create greenhouse gases and use lots of land. Climate change also brings new challenges, like pests and diseases that can harm crops. To protect the environment, people are looking for better ways to farm that use less water, keep soil healthy, and reduce pollution.

Disciplines

Agricultural economics

Main article: Agricultural economics

Agricultural economics studies how farming relates to money, business, and markets. It looks at how food is made, sold, and used. People have been studying this since the late 1800s. Big changes in farming have affected economies around the world. For example, ways of farming like tenant farming and sharecropping changed how people worked and lived.

Governments can change farming with rules like taxes and help for farmers. These rules have changed farming in both rich and poor countries. Even today, some rules still make it hard for farmers to sell their crops fairly.

Agricultural science

Main article: Agricultural science

Further information: Agronomy

Agricultural science is a big field that uses many kinds of science to understand farming. It includes studying plants, soil, and how to grow crops better. Scientists also look at ways to protect plants from pests and keep the soil healthy.

People started studying agriculture in the 1700s. Since then, scientists have done many experiments to learn how to make farming better. In the United States, special money was given to help farmers learn about fertilizers. Scientists also work on natural ways to control harmful insects.

Policy

Main article: Agricultural policy

Agricultural policy refers to the rules and actions that governments take to support farming and the trade of food products. These policies aim to create stable markets, protect the environment, and ensure that there is enough safe and high-quality food for everyone.

Governments use different methods to support farmers, such as providing financial help or encouraging good farming practices. However, some policies can lead to inefficiency and harm the environment. For example, using too much land for animal farming instead of plants can waste resources. Many groups, including farmers, businesses, and environmental organizations, influence these policies. International groups also work together to create rules that help reduce hunger and support sustainable farming practices.