No one knows precisely when humans first started a sustained, systematic practice of agriculture, but evidence has shown signs of agriculture in the Middle East and Mexico that date back to approximately 7000 BC. Some of the earliest cultivated crops included emmer wheat, wild barley, pumpkin, peas, and beans. The presence of larger scale, systematic cultivation often preceded or accompanied the rise of villages and cities and the formation of organized civilization.

The Farm

The basic working unit of agriculture is the farm. Farmers plant seeds, cultivate soil and crops, harvest crops, and send them to market; or they breed animals for their milk, meat, hides, or other products. The basic farm cycle consists of planting, cultivation, harvesting, transport, processing, and marketing.

Inputs

Farmers rely heavily on inputs, natural or man-made resources that allow them to grow, cultivate and harvest crops, or to breed animals. Inputs can be very costly and a farmer must usually go into debt to acquire them, on the hope that the farm's earnings will be sufficient to repay the debt, and, hopefully, provide a profit. To succeed, a farmer must learn techniques to use and manage these resources, such as land, soil, seed, and water, in the best way possible. Inputs include:

• land: maximizing a limited amount of land is important. Farmers sometimes own their own land, or they may lease it. In controlled economies, such as the former Soviet Union, farmers may work collectively on state-owned lands.
• soil: tilling (breaking up) and conditioning the soil with manure or compost can help activate beneficial organisms in the soil, reduce erosion, provide readily-absorbed nutrients and increase production.
• seed: seed can be "natural" (or "heirloom"), hybrid, or genetically manipulated (GM). Natural seed is often taken from a portion of a farmer's own crops. Farming tradition has often included the sharing and trading of seed varieties among farmers. Hybrids are a cross of 2 or more crop varieties selected for their positive growing characteristics (such as short growing season, or resistance to heat, cold, or disease). Hybrid seeds are sterile, and must be purchased. Genetically manipulated seeds are made by the very complex processes of splicing genetic material from one plant species onto that of another.
• water: plants need sufficient water to grow. In drier areas, farmers may irrigate their fields.
• fertilizers: fertilizers are synthetic (chemical) sources of nutrients (usually nitrogen, phosphorous, and potassium, designated with the chemical symbols N, P, and K, respectively) that help plants grow faster and stronger. Fertilizers must be formulated so that their nutrients are easily absorbed by crops.
• manure (or other soil conditioners, such as compost): manure and compost condition and provide nutrients for the soil. Manure is animal excrement, and compost is decomposed organic matter, usually from plants.
• labor: farming is very labor-intensive work, but it has also traditionally been one of the lowest-paying economic sectors. On family farms, labor has always been provided by family members, but larger commercial farms often use hired labor. When farm workers are too scarce, or labor costs are too high, farmers will often mechanize.
• machinery: in recent decades, the trend all over the world has been for young farm workers to move to the cities to find better-paying work. The result has been a shortage in farm laborers. Machinery, such as tractors, plows, harvesters, threshers, and balers help farmers automate mundane, back-breaking work.
• pesticides: pesticides are chemical insect killers that often have toxic effects on soil and water, as well as animals, farm workers, and consumers. There are some natural pesticides, such as neem, a substance that has been used for centuries in India.
• herbicides: herbicides are chemical plant killers. They are used to kill weeds that compete with crops for root space, nutrients, and water. Sometimes the unintentional effect of using herbicides is to kill the plants they were intended to save. Long-term use of herbicides (as well as pesticides and fertilizers) leads to pollution of soil and ground water.

Crops

Choosing which crops to grow depends on many different factors, such as climate, prospects for selling the harvest, and type of soil. Some crops are grown for food for humans, some are grown to be feed for animals, some (such as cotton) are grown for industrial uses, and still others are grown to enrich the soil. Among the world's most common crops are:

• wheat: Wheat is one of the most common grains grown throughout the world. It is also one of the oldest known crops, and can grow in a wide range of soils and climates.
• rice: rice is the most popular crop in Asia and thrives in warmer climates.
• corn (maize): corn originated in the Americas and was a popular import in Europe, where it is often used as animal feed.
• soybeans: soybeans have become more popular as food processing technology has developed more uses. Soybean oil has many food and industrial uses.

Hazards

Farmers must learn to negotiate many uncertainties that can have potentially disastrous effects on their crops.

• pests
• weather: excessive heat or cold, drought or floods can all have devastating effects on crops.
• disease: plant diseases have long been a major threat to farmers.
• competing plants, such as weeds
• prices/markets
• supply/demand

Most of the research in farming and agriculture has been aimed at helping farmers overcome these uncertainties and maximize resources and production.

The "Green Revolution" and Scientific Farming

Scientific farming methods try to improve on nature by boosting the short-term abilities of plants to fight disease, absorb nutrients from soil and fertilizers, and provide better yields. Scientific farming has became widespread in the latter half of the 20th century and has been instrumental in the change from family farms to larger, "corporate" farms.

With great increases in population in this century, especially in the Third World, there has been growing concern that traditional agricultural methods would be unable to keep up with increased demand for food.

In the 1940's, a handful of scientists, sponsored by the Rockefeller Foundation, were invited to Mexico to look into ways to modernize and improve the efficiency of Mexican farmers. The group, led by agronomist Norman Borlaug, investigated a combination of factors:

• Hybrid seeds: a hybrid seed is developed by mating, or cross-breeding, 2 or more species of plants. The hope is that the resulting hybrid will have the most positive characteristics of all the crossed varieties. Hybrids are sterile, and must continually be reproduced by cross-breeding methods
• intensive irrigation
• intensive use of fertilizers

This research found rapid success. In many cases, farmers using Green Revolution hybrids were able to double their output in less than a decade.

The Green Revolution in Asia

In the 1960's, Green Revolution methods were transplanted to Asia, but the emphasis of hybrid research was on wheat and rice. The results were impressive:

                         OUTPUT (metric tons)
                    China                  South Asia
             rice   wheat  maize      rice   wheat   maize 
 1961-1965   72.2    19.1    20       72.7    15.5      6  
 1986-1990  176.9    90.1    80      135.9    63.5     10  

Critics claim that these methods foster dependence on expensive inputs, diminish the natural genetic diversity and resilience of "natural" seed, and promote the intensive use of fertilizers, herbicides, and insecticides, which can lead to pollution of soil and groundwater. There is some evidence that only the wealthiest farmers with large farms and the resources to acquire expensive inputs were able to benefit from Green Revolution methods.

Two Types of Farming Methods

There are, of course, many types of farms and farming techniques, but the latter half of the 20th century has seen a kind of polarization of 2 distinct types of farming: scientific farming and sustainable agriculture. Both methods attempt to increase yields and use resources as efficiently as possible, but how they try to achieve these goals is very different. While scientific farming relies on technology to try to improve on nature, sustainable agriculture tries to nurture and foster nature's own processes.

Some Characteristics of Scientific Farming

• monoculture: intense cultivation of only one or two types of crops. In the short term, this method can increase production, but in the long term, it can make plants less resistant to diseases and pests, and increase the need for costly inputs.
• pollution: caused by the leeching of insecticides, fertilizers, and herbicides into soil and ground water. Also, residues of pesticides and herbicides on plants can cause serious health hazards to farm workers and consumers.
• depletion of genetic stock: hybrid seeds are sterile. While the use of genetically altered seeds may lead to short term gains in productivity, in the long term they lead to a lessening of genetic diversity, dependence of farmers on biotechnology, and the need for farmers to take on additional debt to pay for expensive inputs.
• dependence and debt: while scientific farming methods have provided impressive gains in production, they do lead to dependence on manufacturers of seed, fertilizers, and other costly inputs. The cost makes these methods problematic for smaller farmers, who must borrow heavily to be able to afford the "high-tech" inputs.

Some Characteristics of Sustainable Agriculture

Generally, sustainable agriculture favors (and often requires) the use of organic natural substances, including organic seed (seed not treated with pesticides or other chemicals), organic soil amendments, such as compost or bat guano (bat feces), and organic pesticides, such as neem.

• crop rotation: alternating several different kinds of crops in fields helps plants build or retain resistance to disease, and can help restore essential nutrients and microorganisms to the soil.
• integrated pest management: integrated pest management uses low- impact methods that emphasize strategic planting, the use of beneficial insects, organic pest control compounds, and other methods. Integrated pest management has better long-term impact on the environment than extensive use of chemical pesticides.
• organic soil amendments, such as compost and manure.
• independence (financial and otherwise): sustainable agriculture relies on nature's own substances and processes. The farm attempts to produce everything it needs and to find productive uses for its own waste products and byproducts (such as compost and manure).

While sustainable agriculture has been proven to provide safe, reliable crops in a way that has a minimum negative impact on land and people, gains in productivity have not kept up with the gains made with scientific methods. Critics of sustainable agriculture argue that without the intervention of science, outputs will not be able to keep up with anticipated increases in demand, and that crops grown with sustainable methods are simply too expensive to benefit the general public.

Processing

Many food crops are consumed with a minimum of processing, but the trend in developed countries is toward more processing. For example, instead of buying lettuce, tomatoes, carrots, and various greens at a local farmers market, consumers can now buy a pre-packaged salad (with added chemical preservatives) in a local hypermarket chain store. Processing food products "adds value" to the product, which essentially means that companies can charge more to consumers. The use of processed foods was pioneered in the United States, and is increasing in other parts of the world.

Agribusiness

Throughout history, farming has been a family enterprise, with most farmers taking care of their own needs, and maybe producing a little extra to sell or trade. In the latter half of the 20th century, the trend in the more developed nations (and increasingly in the less-developed nations) is toward corporate farms. The Green Revolution made impressive gains in crop yields, but the new methods and technologies often bypassed smaller farmers, who did not have the resources to acquire the costly inputs needed to grow Green Revolution hybrids.

Vertical integration: We have seen that agriculture has several phases to a growing and consuming cycle: planting, cultivating, harvesting, storage, transport, processing, and marketing. Traditional farming practices have emphasized the farmer's participation in the phases actually connected with the growing and harvesting of crops. Often, local specialists would be involved in other phases, such as transport or marketing.

A modern trend, however, has been toward vertical integration: one company being responsible for all, or most, phases in the cycle. Large agribusiness companies are manufacturing inputs (such as seed, fertilizer, and pesticides); acquiring farms; managing the transport, processing, and marketing of their products; and researching new ways to improve their products through processes such as genetic engineering.

The Decline of the Family Farm

Accompanying the rise of scientific farming and the widespread increase of yields of many crops and animals, prices for agricultural goods have remained fairly flat from the 1970's well into the 1990's. This has been a positive development for consumers, but the effect on farmers, especially small farmers, has been disastrous.

This is one of the many economic uncertainties of farming as a business. There is a fine balancing act with prices, demand, and production, and world and local economic conditions. Increased production means increased supply and low prices for the farmer, while decreased production means higher prices for both farmer and consumer. Here are some common scenarios:

• A drought would mean lower production, higher prices, and potential diasaster for a farmer; crops might sell for higher prices, but demand might be significantly less than if the price were lower.
• An economic crisis in the US or Europe would mean that an Asian rice farmer might not be able to sell his or her harvest in those markets.
• A weakening yen would mean a higher price in Japan for imported for US apples, and Japanese consumers would stick to their cheaper, and more familiar domestic apples.

Government Policies

It is in the best interests of all governments to formulate policies that are beneficial to farmers. A stable, reasonably-priced food supply and productive, well-paid farmers are two very important components of a stable society. However, the combination of cheap food for consumers and high market prices for farmers is very difficult to achieve. Some common policy tools include:

• subsidies: a subsidy is money a government pays to farmers to guaranty that they receive a certain price for their crops.
• production limits: some governments pay farmers NOT to grow certain crops, or even to leave some land unused (fallow). The goal of this policy is to reduce supply and keep prices relatively high.
• tariffs on competing foreign crops: government often impose tariffs, or taxes, on imported crops, which makes the cost of imports much higher to the consumer.
• agricultural research: governments often finance agricultural research to investigate promoting better-yielding crop varieties, eliminate diseases, fight pests, improve processing methods, etc.

Genetics

The science of genetics has made astonishing progress in the last half of the 20th century. Geneticists have made remarkable gains in deciphering the genetic code that gives each species its particular traits. They have discovered methods of transplanting genetic material from one species to another, and have been able to transfer such genetic traits as disease resistance, time to maturity, or the yield that a plant produces.

Unlike hybrids, genetically manipulated (GM) plants are not sterile, but some agribusiness firms have produced so-called "terminator" genes, which prevent a GM plant from germinating and reproducing. Another development is a plant that is resistant to a particular variety of herbicide. Both of these developments have been very controversial, provoking charges that they have been developed, not with the best interests of farmers in mind, but with the goal of selling more seeds and herbicides.

While early success has been considerable, there is widespread concern that we just don't know enough about the long-term consequences of genetic manipulation of crops and animals. For example, if the terminator genes from a GM wheat species were somehow to cross-pollinate with any number of wild plants around them, it could well mean the end of those wild varieties. Likewise, if the herbicide-resistance gene were to pollinate with a species of weed, the result might be to create a species of nearly indestructible superweed.

The Future of Agriculture

If agriculture is to meet the demands and uncertainties of the future, here are some main areas that will need to be addressed:

• sustainable agriculture will need to find ways to increase yields comparable to those of scientific farming methods.
• scientific methods will need to look at ways of improving yields that are not so reliant on the heavy use of pesticides and fertilizers.
• agricultural economists will need to look beyond yields and output, and find policies that insure that any technical advances are not out of reach (for economic or social reasons) of any farmer, regardless of gender, class, or economic level. The people involved in farming (farmers and farm laborers) are not just numbers.
• geneticists will have to look seriously and thoroughly at the questions of what unplanned effects might result from extensive planting and cultivating of genetically manipulated breeds.

What is needed is a comprehensive view, which keeps in mind technology, environment and ecosystems, social questions, and the difficult task of feeding an ever-increasing population with affordable food, in a way that is fair to all types of farmers and consumers.