Dynamics of Danish Agricultural Landscapes and the Roles of Organic Farming

Agriculture manages about 2/3 of the Danish land area. As a consequence, agricultural land use consequently has a major influence on the appearance of the Danish landscape in terms of its spatial composition and structure. Alterations of agricultural practices always imply potential changes in landscape composition and structure. Qua its definition and ensuing standards, organic farming embodies a particular kind of agricultural production. Consequently, the conversion to organic farming implies potential changes in the spatial composition and structure of the landscape. As organic farming occupies approx. 6% of all agricultural land in Denmark, it is relevant to investigate potential effects of this conversion on the landscape. Furthermore, within the political and public spheres organic farming is widely expected or at least supposed to have a beneficial effect on agricultural landscapes. While principles of organic farming embrace the protection and management of uncultivated landscape elements as habitats for wild species, standards and rules do, at least in Denmark, only concern cultivation practices and animal husbandry. Furthermore, research on organic farming – landscape relations is scarce and results and findings of existing studies are often biased by inadequate methods, particularly due to very small samples and limited spatial and temporal scales. Based on this background the central aim of this Ph.D. thesis is to elucidate relations between organic farming and spatial structure and composition of agricultural landscapes. Two major methodologies were applied. First, an analysis of Danish national agricultural registers from 1998, 2001 and 2004 aimed at investigating relationships between organic farming and landscape composition and structure in terms of crop diversity and field sizes. Second, an analysis for three case areas comprising 40 organic and 72 conventional farms aimed at investigating relationships between organic farming and landscape composition and structure in terms of field sizes and densities of different uncultivated landscape elements. This case area investigation was based on the interpretation of aerial photos from 1954, 1982, 1995 and 2002. Analyses at national scale pointed at significantly higher crop diversities and smaller field sizes on organic farms. In general scale enlargement in agriculture with decreasing crop diversity and increasing field sizes characterized the period from 1998 – 2004. But conversion to organic farming weakened or even reversed this trend. The case area analysis showed no significant direct relationships between organic farming and landscape composition. However, taking into account differences between organic and conventional farms with respect to other farm specific properties, the results at case area scale point at differences in landscape composition and changes in landscape composition between organic and conventional farming, which were influenced by differences in terms of farms size, soil conditions and topography. On the basis of these results it is concluded that organic agriculture as a specific type of agricultural production is characterized by a ban on chemical fertilizers. Compared to their conventional counterparts, organic farmers therefore need to maintain nutrient balances by means of a more complex crop rotation, which implies larger crop diversity and smaller field sizes. This obvious effect of organic farming has a potential to counteract some of the negative influences of a continued scale enlargement in the agricultural sector, as it is being predicted in future scenarios. Several authors argue that organic farmers due to their recognition of environmental issues are more active in landscape management inducing higher densities of uncultivated landscape elements on organic farms. Such relationship could, however, not be confirmed in this study. Differences in terms of farm sizes and soil and slope conditions lead indirectly to differences in densities of these uncultivated landscape elements between organic and conventional farms. However, differences in farm sizes as well as soil and slope conditions are not a direct consequence of organic farming standards and rules. It is thus argued that higher densities of uncultivated landscape elements on organic farms are not an outcome of organic farming as a specific type of agricultural production.