Conversion of agricultural land - use of spatial analysis for exploring conversion of agricultural land to non-agricultural uses

The agricultural area covers only 3.7 per cent of the total land area in Norway. Much of the most productive areas are within, or close to, growing urban areas. Over time, this has led to considerable conversion of agricultural land to residential areas, roads, industry areas and other built up areas. Protection of farmland is frequently on the political agenda, and national goals have been agreed to protect the cultivated soil as a collective good.

Conversions of cultivated and cultivable land permitted to non-agricultural uses are currently reported through KOSTRA (Municipality-State-Reporting). These areas are planned to be used for other purposes. However, it is not evident whether, or when, these plans are implemented. In order to develop statistics on actual conversion of farmland to non-agricultural uses, Statistics Norway in cooperation with the Norwegian Institute of Bioeconomy Research have taken on this project. The main purpose of the project has been to design a model to provide statistics about type of non-agricultural use, proximity to urban areas and soil quality. Conversion of agricultural land caused by agricultural uses (agricultural buildings etc.) is also a part of the project.

Briefly, the method used in the project was to identify converted farmland by the use of several geographical sources. We ran a GIS analysis (GIS= Geographical Information System) using two main data sources; area resource map as of 2010 which give a status of the agricultural areas before 2010, and Statistics Norway’s land use map 2016 covering all built up areas by the end of year 2015. Areas classified as farmland before 2010, but converted to built-up areas in 2015, were identified by an overlay analysis. These areas were the objective for further analysis. The register data and the evolved method generated reliable results for cultivated land, but with more uncertain results for cultivable land.

A total of 9 760 hectares of agricultural land were converted to other uses in the period 2004-2015. This is equal to 0.9 per cent of the agricultural land area registered in the zero-time point of the analysis. Most farmland was converted to non-agricultural uses in the county of Rogaland, with 1 700 hectares of agricultural area. This figure is equal to 1.6 per cent of all registered farmland in the county. Less farmland was converted in Oslo (30 hectares), but on the other side, this area amounted to the highest portion among all the counties by 3.4 per cent of Oslo’s cultivated land.

There is a strong correlation between conversion of farmland and urban areas. Overall, 23 per cent of the total conversion of farmland took place inside the urban areas. Furthermore, 27 per cent took place close to and less than 1 kilometre outside urban areas. Scattered development in rural areas (at least 3 kilometres from the urban areas) accounted for 31 per cent. In urban areas, agricultural land is attractive as development area because of favourable location and cost-effectiveness. In the period 2004-2015, as much as 12 per cent of all cultivated land in urban areas was converted to built-up areas. The corresponding share for locations less than 1 kilometre outside the urban areas was 1.1 per cent.

Residential areas constituted the greatest share of the converted land. A total of 2 530 hectares of farmland were converted to residential areas, of which 4 out of 5 hectares were used for single-unit dwellings and semi-detached houses.

The agricultural holdings themselves accounted for 22 per cent of the converted area. Equal to other purposes, the agricultural sector converted farmland of high soil quality. Of the converted arable land, 72 per cent were classified as of very high quality.