Arable Land as a Resource

Abstract

Arable land can be treated as a production resource, with a natural resource component and an anthropogenic capital component. It is a stock, giving a renewable flow. The arable land resource has a quantitative dimension (hectares) and a qualitative one, which may be described by innumerable edaphic, topographic and climatic site parameters. Instead of measuring the resource stock (hectares, site parameter data), the resource is measured by its capacity to generate a flow. Physical measurements are derived by combining existing statistics with production functions. They are expressed in kilo barley-equivalents per hectare, and calculated for each of the 420 “homogenous” agricultural districts in Sweden. A concept called standard-hectares is developed, making acreage comparisons possible amongst different grades of land. The economic measure of the resources is land rent As the residual of revenues minus costs in crop production it should reflect the different use-capacities of various plots of land. Swedish arable resources measured by land rents are fairly heterogeneous, showing distinct regional patterns. In 1983 the rent on Swedish tilled land was nearly normally distributed around a mean of US$ 100 per hectare. From 1968 to 1983 land rents declined, especially in the far south and in the north. The arable land resource situation is further illustrated by a new diagram that plots land rent against cumulative acreage. The barley-equivalents and land rents methods each provide a single, cardinal measure appropriate for comparing land of different quality. Further, a computerized model of Swedish arable resources was used to study the impacts of resource influencing factors. Possible resource situations are simulated on the basis of assumptions about the effects of factors like subsoil compaction, erosion, photochemical oxidants, on yields or costs. Air pollutants like ozone, subsoil compaction and urban expansion appear to be the most menacing factors. The possible effects are of such magnitude as to constitute a risk to the security of our food supply. Many of these factors are likely to exert their greatest negative influence on the plains in south and central Sweden, thus causing changes in the regional distribution of arable land resources, and also tending to make them less heterogeneous in the future.