Combined map data reveals built-down farmland
Photo: Erling Fløistad
With a clear and intensified soil protection goal, there is a growing need for reliable figures of how much cultivated land is built down every year.
Through the national reporting system KOSTRA, municipalities report how much agricultural land is declared rezoned each year. These figures do not always correspond to how much is actually built down.
NIBIO has tested a method to provide an estimate of how much farmland is built down each year. The model is based on selected map sources, and calculates:
- How much cultivated land was built down the previous year
- What the land is used for, and
- Consequences for food production.
In the current soil protection strategy, the Storting has determined that annual rezoning of cultivated land should remain below 3000 decares. According to Statistics Norway, 3900 decares of cultivated land were rezoned in 2020. An additional 6500 decares of cultivable land were declared rezoned.
Delays are part of the explanation
The statistics from KOSTRA are based on figures of declared rezoned agricultural land. However, it can take several years from when cultivated land is declared rezoned until development begins.
Investigations from Statistics Norway show that figures of building on cultivated land in the 2016–2019 period are higher than what was reported through KOSTRA. The differences can likely be explained in part by the delay from when rezoning is planned until building takes place, and partly from rezoning that is not reported.
The work that NIBIO has done on behalf of the Ministry of Agriculture and Food aims to show land that has actually been built down in the previous year and will be a useful supplement to the KOSTRA figures.
The central map sources for NIBIO’s measurement method are the National Land Resource Map AR5, which shows existing agricultural land, building points from the national property register and the National Roads Database.