Agriculture

I

Introduction

Agriculture, science and industry of managing the growth of plants and animals for human use. In a broad sense, agriculture includes cultivation of the soil (soil management), growing and harvesting of crops (crop farming), breeding and raising of livestock (animal husbandry), dairy farming, forestry, and poultry farming.

Regional and national agriculture are covered in more detail in individual country and continent articles.

II

Modern Agriculture

Modern agriculture is characterized by relatively high levels of inputs, often produced off-farm, and high levels of outputs. Standard farm management practice is to divide these inputs into those that vary directly with output (variable inputs) and those that do not (fixed inputs). Fixed inputs include agricultural machinery, and modern agriculture is dependent on the manufacture of machinery for cultivations, harvesting, and other farm operations. Machinery is also needed for draining soils (see Drainage) and, in drier climates, irrigating crops (see Irrigation).

Mechanization has been one of the main characteristics of 20th-century agriculture, easing much of the back-breaking toil of the farmer. Developments in machinery, along with advances in plant breeding and animal breeding, have helped to increase agricultural productivity: it is now possible to produce more output per unit of inputs, fixed and variable. In Western countries, there has also been a trend towards larger, more powerful machinery at the expense of full-time labour. For this type of machinery to be economic, large fields and farms are needed and the substitution of machinery for labour is one reason why farm size has increased in Western countries. The high ratio of machinery to labour inputs in modern agriculture has two further consequences. First, it is intensive in its requirements for energy, and is therefore reliant on stable supplies of fuel; second, it is relatively capital intensive; thus a properly functioning financial system is also a requirement for the success of modern agriculture.

The variable inputs include seeds, fertilizers, and crop protection products (herbicides, pesticides, and fungicides), and feed and veterinary treatments for livestock production. Advances in crop and animal science have led to a much better match between crop and animal needs for variable inputs, resulting in less waste. For example, the timing and level of nitrogen fertilizer applied to crops can be closely matched to the crop’s needs; this means that the farmer can apply less fertilizer, cut his costs of production, and reduce losses of nitrogen to the environment.

Plant breeding and, more recently, genetic modification of crops such as soya and cotton, contribute substantially to farm productivity. Improved understanding of genetics has also placed livestock breeding on a more scientific basis. Despite these improvements, yields for winter wheat, one of the world’s major food crops, have increased by less than in previous decades. Over the period 1984-2004, for example, yields increased from 7.7 to 7.8 tonnes per hectare (19 to 19.3 tonnes per acre) in the United Kingdom and from 2.6 to 2.9 tonnes per hectare (6.4 to 7.2 tonnes per acre) in the United States. In Asia, yield increases have been more pronounced: wheat yields in India have caught up with the United States, increasing from 1.8 to 2.7 tonnes per hectare (4.5 to 6.7 tonnes per acre) over the same period.

Modern agriculture is usually linked to an advanced food processing and marketing sector, although the two can be quite distinct, with most of the activities that transform agricultural products into what people want to eat—the value added—taking place beyond the farm gate. Methods of processing, freezing, chilling, and preserving have changed the nature of the foods that people eat, allowing produce to be stored for long periods of time. Food processing, in developed countries, is now a large-scale industry.

Organic farming methods are becoming more widely practised in developing countries as a reaction to recent food scares generated by bovine spongiform encephalopathy (BSE) and concerns over pesticide residues and the intensive nature of modern farming. In Austria, for example, some 13 per cent of farmland is organic; in the United Kingdom, it is nearer 4 per cent.

III

World Agriculture

Over the 10,000-year period since agriculture was first developed, people have discovered the food value of wild plants and animals and have domesticated and bred them. The most important are cereals, such as wheat, rice, barley, corn, and rye; sugar cane and sugar beet; animals that are used for meat, such as sheep, cattle, goats, and pigs; poultry, such as chickens, ducks, and turkeys; and such products as milk, cheese, eggs, nuts, and oils. Fruits, vegetables, and olives are also major food sources for human beings. Feed grains for animals include soya beans, field corn, and sorghum. Separate articles on individual plants, including grasses and silage (fodder), and animals contain further information.

Agricultural income is also derived from non-food crops such as rubber, fibre plants, tobacco, and oilseeds used in synthetic chemical compounds, as well as from the raising of animals for their pelts.

The conditions that determine what will be raised include climate, ecology, water supply, and terrain. Problems over extensive deforestation for agriculture in developing countries have intensified in recent decades. Tropical deforestation increased rapidly after 1950, helped by the increased availability of heavy machinery. Historically, as it developed over the centuries in temperate regions, agriculture has depended upon forest removal; for example, most of England’s woodlands were deforested by 1350.

The proportion of people working in agriculture has fallen, from 52 per cent of the world’s labour force in 1990 to 43 per cent in 2004. The distribution in 2004 ranged from 55 per cent of the total labour force in Africa to about 1.8 per cent in the United Kingdom. In Asia, the figure was 54 per cent; in Latin America, 18 per cent; in Europe, 8 per cent; and in North America, 2 per cent. While agriculture has an important contribution to make to economic growth, particularly during the early stages of a country’s development, economic growth inevitably leads to a decline in the contribution of agriculture to the economy and as a source of employment.

Farm size varies widely from region to region. For example, in the early 2000s the average for Canadian farms was about 273 hectares (675 acres) per farm, while the average size of a single landholding in Asia was somewhat less than 1 hectare (2.47 acres). The major part of production often comes from the largest farms: for example, in the United Kingdom, just over half of food production comes from the largest 10 per cent of farms.

Size also depends on the purpose of the farm. Commercial farming, or production for cash, is usually on large holdings. The latifundia of Latin America are large, privately owned estates worked by tenant labour. Single-crop plantations produce tea, rubber, and cocoa. Wheat farms are most efficient when they comprise some thousands of hectares and can be worked by teams of people and machines. Australian sheep stations and other livestock farms must be large to provide grazing for thousands of animals. The agricultural plots of Chinese communes and the cooperative farms held by Peruvian communities are other necessarily large agricultural units, as were the collective farms that were owned and operated by state employees in the former USSR.

Individual subsistence farms or small-family mixed-farm operations (see Smallholding) are decreasing in number in developed countries but are still numerous in the developing countries of Africa and Asia. Nomadic herders range over large areas in sub-Saharan Africa, Afghanistan, and Lapland; and herding is a major part of agriculture in such areas as Mongolia. A counter-trend in developed countries is the increase in part-time farming, where farmers, often on small farms, gain a substantial part of their income in other occupations.

The importance of an individual country as an exporter of agricultural products depends on many variables. Among them is the possibility that the country is inadequately developed on an industrial level to produce processed goods in sufficient quantity or technical sophistication. Such agricultural exporters include Ghana, with cocoa, and Myanmar (formerly Burma), with rice. On the other hand, an exceptionally well-developed country may produce surpluses that are not needed by its own population; this is the case with the United States, Canada, and the European Union (EU); these surpluses may be encouraged by the operation of agricultural policies, such as the EU’s Common Agricultural Policy.

Because nations depend on agriculture for food, raw materials, and its contribution to national income, trade in agriculture is a constant international concern. It is regulated by international agreements, overseen by the World Trade Organization (WTO). Trading groups such as the EU have agricultural policies that restrict trade, to the advantage of their own farmers, but to the disadvantage of agricultural exporting nations, many of which are developing countries. One of the main aims of the WTO is to liberalize trade in agricultural commodities.

IV

History

The history of agriculture may be divided into four broad periods of unequal length, differing widely in date according to region: prehistoric; historic through the Roman period; feudal; and scientific.