Land Use

V

Agricultural Land Use

One of the best-known models of agricultural land use was developed in the 1820s by the German agriculturalist Johann Heinrich von Thünen and published in 1826 as Der Isolierte Staat (The Isolated State). It attempted to explain why agricultural land use differs with distance from market centres. In developing his theory von Thünen initially assumed a wilderness surrounding a level agricultural plain with uniform climate, soil fertility, and access to the single market centre located in the centre of the plain—the “isolated state”. He also assumed that transport costs would increase in direct proportion to distance from the market centre. Based on these assumptions he proposed two models: the first to explain differences in the intensity of production of a particular crop; the second to explain the distribution of different crops relative to the market centre.

A

Intensity of Production

According to the first model, intensity of production of a crop decreases with distance from the market centre. This is because all farmers in the isolated state face the same costs of production for a given unit of land, have the same crop yield from the land unit, and receive the same price per weight unit for that crop. Thus, the cost of transport is the only variable factor and therefore the determinant of the locational rent that the farmer receives for the crop—that is the total revenue received from the crop grown on the unit of land less the total costs of production and the transport costs to market.

This can be demonstrated by an example. Two farmers, A and B, produce 100 tonnes of wheat on 1 hectare of land for a total production cost of US$1,000. Transport costs to market are US$2 per tonne per km, and the market price is US$100 per tonne. Farmer A, who lives 5 km from the market has a total revenue per hectare of US$10,000 (100 tonnes at US$100 per tonne). Transport costs per hectare are US$1,000 (100 tonnes at US$2 per tonne over 5 km), and total costs are US$2,000 (US$1,000 production costs plus US$1,000 transport costs). Farmer A's locational rent would therefore be US$8,000 per hectare (US$10,000 revenue less US$2,000 total costs). Farmer B lives 25 km from the market and has the same revenue of US$10,000, However, Farmer B's transport costs are US$5,000 (100 x 2 x 25), giving total costs of US$6,000 (1,000 + 5,000), and a locational rent of US$4,000 (10,000 - 6,000).

This difference in locational rents becomes more marked if the two farmers increase yields by intensifying productivity—thereby increasing production costs—through the use of more inputs such as labour or capital. However, yields do not normally increase in direct proportion to the increase in production costs. Thus, when farmers A and B increase production cost to US$2,500 per hectare, yields increase to only 150 tonnes. Farmer A's locational rent in this case is US$11,000 ([150 x 100] - [2,500 + {150 x 2 x 5}]), an increase of 37 per cent over the previous locational rent. Farmer B's locational rent is US$5,000 ([150 x 100] - [2,500 + {150 x 2 x 25}]), an increase of only 25 per cent over the previous figure.

B

Crop Location

The second model, which follows on from the first, says that the location of different agricultural activities is determined by production costs and yields per land unit, and by transport costs and market prices per weight unit. At any given distance from the market centre the crop with the highest locational rent will be grown. Products with the highest transport costs (and also usually the highest production costs), and thus those whose locational rent decreases most sharply with distance, will be grown closer to the market centre. This leads to a pattern of concentric production zones radiating out from the market centre, with activities like market gardening nearest the market centre and the outermost zone given over to extensive farming practices such as livestock grazing.

Von Thünen subsequently attempted to bring the models closer to reality by introducing factors such as a major road or river, to provide faster, cheaper transport, or another market centre. This created much more complex land-use structures. Tests of his modified model have been made in many countries, including Uruguay, Australia, and Ethiopia, and its underlying concepts have been found to be valid. Today, however, economic influences are even more complex than those considered by von Thünen. In addition, certain agricultural activities included in his model, wood production for fuel, for example, have little relevance in countries with developed economies.

C

Modern Influences on Agricultural Land Use

Economic factors continue to exert a major influence on agricultural land use, especially the cost of loans and the impact of government intervention. Controls on food production, including the availability of subsidies, the fixing of quotas, the setting aside of land in return for monetary compensation, and schemes to make farms less dependent on one activity, all combine to create a complex and often fast-changing pattern of agricultural land use. The scale of the impact of these factors is also much greater than that envisaged by von Thünen. In Europe, for example, land-use decisions by farmers are increasingly influenced by the operation of the European Union's (EU) Common Agricultural Policy, whereby a policy decision taken at the EU headquarters in Brussels may cause changes in land use in many different locations. In addition, modern transport links enable agricultural produce to be marketed on a worldwide basis. Decisions on what crops are grown in any one area may represent a response to demand from the other side of the globe.

VI

Models of Urban Land Use

In towns and cities patterns of land use represent a response to the various processes of urban growth and decline. Competition for land is strong both between and within different functions. For example, land on the edge of towns may be wanted for residential and commercial purposes while businesses may compete for the best locations within the central business district (CBD) of the town. Usually located in the centre of a town, the CBD is the area of most intense competition for land, with the highest rents, and in larger cities is often associated with the traditional area of financial services, such as Wall Street in New York and the City of London. Traditional models of urban structure focus on the structure, or urban morphology, of towns, emphasizing the relationship of different urban zones with the centre and with each other.