Conversion of agricultural soils in Austria—a case study for a community in Upper Austria

The annual soil loss in Austria is high. The Environment Agency Austria reports, since several years, that the daily soil conversion amounts to more than 10 ha, which is by a factor of 5 above the sustainable soil conversion rate (https://www.umweltbundesamt.at/umweltsituation/raumordnung/rp_flaecheninanspruchnahme/). The majority is potential cropland and grassland that is converted into area for buildings and streets, thereby being permanently lost as productive land. The soil loss is often memorably compared with multitudes of areas of soccer pitches (approximately 0.5 ha) in order to emphasize the extent of the challenge of soil protection. The topic raised political attention, and efforts toward soil conservation were prominently placed in the Government Program 2017, the National Climate and Energy Program (#mission2030, BMNT 2018), and the Bio-economy Strategy (BMNT 2019) in order to facilitate a growing supply of biomass and to sustainably ensure the provision of soil ecological functions. The relevance of productive and functional soils was emphasized in the Environment Control Report (UBA, 2019).

On top of soil loss as a consequence of structural change of the society, climate change is posing an additional challenge. At present, sites in the North-East of Austria have the highest production potential. Scenarios for the future productivity of grassland and cropland suggest that the productivity of grassland in mountain regions may increase and benefit from climate change, whereas cropland in low elevation will become less productive. Within a few decades, the productivity potential of agricultural sites in central Austria (e.g., Innviertel in Upper Austria) will exceed the productivity of other regions, mostly as a consequence of higher temperatures and a sufficient soil water supply (Haslmayr et al., 2018). In order to provide for future food security, experts suggest to define soil conservation sites (in German: Boden-Vorbehaltsflächen) that should enjoy a certain protection status in order to preferentially maintain them for crop production (Baumgarten, 2019).

We analyzed the extent of soil conversion for a community in Upper Austria where agriculture plays an important role. We used the data from the Austrian Agricultural Soil Survey (https://bodenkarte.at/) in order to quantify the soil conversion during approximately 40 years.

Figure 1 shows an example of the soil map according to the agricultural soil map (BVA, 1976). The map shows the roads, settlements, and the forest area according to the Austrian map with a scale of 1:50,000. The agricultural soils are stratified according to the expertise of the field crew of the soil mapping exercise at the time of the survey. In Figure 2, the cropland that has been converted to other types of land use is indicated as high-quality cropland (brown), medium-quality cropland (blue), low-quality cropland (magenta), and grassland (yellow). The forest area that is represented in light green shades has not changed. The white areas represent cropland remaining as cropland.

Figure 1

Figure 2

Table 1 presents a loss of agricultural land of 15% in approximately half a century. The development of surface took place irrespective of its value as an agricultural production site and was equally distributed among the site-quality classes.

Figure 3 shows the evaluation of land of the community Eggelsberg according to the recent data that are based on the evaluations of the administration (Haslmayr, 2018). The evaluation of soil half a century after the soil survey shows that 36% of the area is evaluated as valuable cropland and 11% as valuable grassland. This land is recommended to be spared from soil sealing in order to secure the nonrenewable resource soil and to ensure food security in Austria (Table 2). Almost half of the agricultural land of the community Eggelsberg is considered to be highly valuable and should be spared from soil sealing.

Figure 3

In a recent assessment of communities by the Center for Public Administration Research, the village Eggelsberg had a highly favorable ranking in an Austrian comparison based on the criteria on its financial management (KDZ, 2020). Despite the pull factor of nearby towns (Braunau and Salzburg), the village Eggelsberg is maintaining its size. More persons are coming to the village for work as persons are going out. The population of the community Eggelsberg is slowly yet constantly increasing (https://www.statistik.at/blickgem/G0201/g40406.pdf). Traditionally, Eggelsberg has been an agriculturally dominated village with several local businesses and a large tannery. A decisive moment in the development of the village was the foundation of an industrial enterprise in 1979 that has developed favorably since then and led to a lasting increase and diversification of job opportunities. Structural change in the society was reflected in the demand for the development of surface area. Schools, recreation and shopping areas, residential areas, a sewage plant, and streets were built. This economically favorable development was possible at the expense of agricultural soil (Haberl 2015). Overall, the converted agricultural land was put to use that meets the life style and infrastructure expectations of the regional population. Two-thirds of the agricultural soils in the area had been qualified as medium quality in 1970 (Table 1). Owing to its origin from glacial and fluvial deposits, the soils have a lower productivity compared with the classical agricultural top soils in the east of the country. Soil quality has apparently not played a major role in the land-use change in the past 50 years. The main share of agricultural soils lost was soils of medium quality, according to the soil evaluation of 1970. Most of the now-sealed former agricultural land is close to the center of villages, where the demand for new residential houses was satisfied. The village of Eggelsberg has grown considerably in the past 50 years, and the area of sealed surfaces for buildings and traffic space has doubled. In the studied area, a similar development took place in the village Ibm and, to a slightly lesser extent, in the village Gundertshausen. Evidently, there was no indication for unconstrained sprawl of the villages. Rather the villages grew gradually, and the claim of productive agricultural land was undisputed by the local population.

The forest cover of approximately 20% of the area was mostly retained. The forests are owned by local farmers, and timber is used for the local demand of wood products, bioenergy, and the traditional reserve for unexpected expenses. Heating systems based on wood chips are abundant. A decentralized energy supply based on regionally available renewable resources is commonly found in farm houses, because the fuel is available from silvicultural interventions. Forests traditionally occupy sites that are unsuitable for agriculture, because of either the steepness of slopes or the low soil fertility. A peculiarity of the region is the forest cover of moist sites adjacent to peatland.

As commonly found, there is not a sudden loss of soils because of a single large project. Instead, the loss is gradual. A new house is built and, within a couple of years, both sides along a street are developed into residential areas; the old school is too small for modern demands, a new unit is erected with a school, a kindergarten, and retirement homes; a new supermarket outlet opens up.

Soil scientists suggest reserving the productive agricultural land in the region in order to ensure a sustainable food production in Austria under warmer conditions. The agricultural sites in Upper Austria are presumingly less vulnerable to the effects of climate change than the agricultural sites in the East of Austria, where water shortage is expected to pose considerable problems in the future. A comparison of Figure 3 and Tables 1 and 2 shows that the appreciation for the land quality in the region has changed. While the land was classified mostly as medium-quality agricultural land before 50 years, the recent map shows high-quality cropland mostly in the north and east of the community of Eggelsberg. Valuable grassland was identified mostly in the south of the community. So far, valuable agricultural land has been spared from soil sealing.

While the concerns about the future availability of agricultural land are at the agenda at the national level, it has not fully conveyed to the local actors. From the perspective of local residents and farmers, a critical shortage of fertile soils is not conceived. The land demand for residential buildings, enterprises, shopping, and parking is given priority over abundant agricultural land. The high valorization of the agricultural land from the viewpoint of scientists is not evident for local farmers. The enterprise structure in the areas follows the general trend in Upper Austria with a slow decrease in the agricultural enterprises. Yet, the area of the agriculturally managed land remains almost unchanged because remaining farmers are buying or leasing the available agricultural land and are increasing their area of managed land (LWF, 2017). The potential future relevance of the agricultural soils is obviously not creating a credible stimulus for actors in agriculture.

The focus on local demand for land in order to build infrastructure and residential areas is not accounting for concerns on possible future shortages of productive land for the provision of food, fodder, and fuel that is clearly expressed in a meta level (Foley et al, 2011, Gaupp et al., 2020). The societal demand for the production of biomass from regional land resources is not sufficiently reflected in land use regulations.

We assessed the change of land use during half a century in a community in Innviertel, Upper Austria. On the basis of the chemical and physical properties of soil, the land was mostly evaluated as medium productive 50 years ago. In the meantime, the effects of climate change have changed that view and have placed about 50% of the area of the community under the category of preferential agricultural land. Yet, societal demands have led to a loss of approximately 15% of the agricultural land in the 50 years. Selling the land for settlement expansions was obviously more attractive than maintaining agriculture and conserving agricultural land in order to meet future demands. Although the expansion of the village was sensible and responsible, a considerable part of potentially valuable agricultural land was sacrificed.