Henrik Vejre

Policies for agricultural nitrogen management—trends, challenges and prospects for improved efficiency in Denmark

With more than 60% of the land farmed, with vulnerable freshwater and marine environments, and with one of the most intensive, export-oriented livestock sectors in the world, the nitrogen (N) pollution pressure from Danish agriculture is severe. Consequently, a series of policy action plans have been implemented since the mid 1980s with significant effects on the surplus, efficiency and environmental loadings of N. This paper reviews the policies and actions taken and their ability to mitigate effects of reactive N (Nr) while maintaining agricultural production. In summary, the average N-surplus has been reduced from approximately 170 kg N ha?1 yr?1 to below 100 kg N ha?1 yr?1 during the past 30 yrs, while the overall N-efficiency for the agricultural sector (crop?+?livestock farming) has increased from around 20?30% to 40?45%, the N-leaching from the field root zone has been halved, and N losses to the aquatic and atmospheric environment have been significantly reduced. This has been achieved through a combination of approaches and measures (ranging from command and control legislation, over market-based regulation and governmental expenditure to information and voluntary action), with specific measures addressing the whole N cascade, in order to improve the quality of ground- and surface waters, and to reduce the deposition to terrestrial natural ecosystems. However, there is still a major challenge in complying with the EU Water Framework and Habitats Directives, calling for new approaches, measures and technologies to mitigate agricultural N losses and control N flows.

Current use of impact models for agri-environment schemes and potential for improvements of policy design and assessment.

Agri-Environment Schemes (AES) to maintain or promote environmentally-friendly farming practices were implemented on about 25% of all agricultural land in the EU by 2002. This article analyses and discusses the actual and potential use of impact models in supporting the design, implementation and evaluation of AES. Impact models identify and establish the causal relationships between policy objectives and policy outcomes. We review and discuss the role of impact models at different stages in the AES policy process, and present results from a survey of impact models underlying 60 agri-environmental schemes in seven EU member states. We distinguished among three categories of impact models (quantitative, qualitative or common sense), depending on the degree of evidence in the formal scheme description, additional documents, or key person interviews. The categories of impact models used mainly depended on whether scheme objectives were related to natural resources, biodiversity or landscape. A higher proportion of schemes dealing with natural resources (primarily water) were based on quantitative impact models, compared to those concerned with biodiversity or landscape. Schemes explicitly targeted either on particular parts of individual farms or specific areas tended to be based more on quantitative impact models compared to whole-farm schemes and broad, horizontal schemes. We conclude that increased and better use of impact models has significant potential to improve efficiency and effectiveness of AES.

Multifunctional agriculture and multifunctional landscapes - land use as an interface

In contemporary sciences dealing with cultural landscapes, the concept of multifunctionality has gained increasing attention in the last decade. The scientific literature displays several attempts to frame the concept (e.g DeVries 2000; Anon 2001; de Groot et al. 2002) but there is much frustration regarding proper sets of broadly based definitions and clear statements concerning the authors’ scientific points of departure (Anon 2001). Multifunctionality is on the one hand used to characterize the activities in the primary production sector, and the land use reflecting the material consequences of the various demands set by the society on land territories — these approaches relate to the agricultural understanding of multifunctionality. On the other hand, multifunctionality is used to characterize the landscape per se. The primary production sector (i.e. agriculture, forestry, horticulture and related land dependent activities) is considered having a primary or main function (production), and related joint productions, typically including a mix of material and non-tangible goods as well as a mix of private and public goods (externalities). Production of food and fibres is generally considered the primary products in this context, but the primary sector produces other material goods too, such as CO2 sequestration, groundwater recharge etc.

Fertilization of Danish Forests: A Review of Experiments

Fertilization experiments in Norway spruce stands on nutrient-poor sites have been practised in Denmark since the eighteenth century. Until 1950, the main aim was to find a nitrogen (N) source that improved the survival of plants in the early growth phase. The N supply could be improved by intercropping with N 2 -fixing plants, and fertilization with phosphorus (P) and potassium (K) improved the growth of the N 2 fixers, thereby improving tree growth and survival. Positive responses of P and K in spruce cultures were seen in the 1960s, and in most cases the N response was dependent on the supply of P and K. Fertilization experiments in mature spruce stands began in the 1960s. Despite 20 yrs of experimentation, no trends can be deduced. The results discouraged fertilization aimed at increasing growth in mature stands, and fertilization stopped in 1989. After 1980, fertilizers were used in experiments aimed at clarifying the causes and effects of forest decline. Fertilization and liming counteracted soil acidification and increased needle nutrient concentrations when they were below deficiency levels. However, positive growth responses have only been recorded in some of the experiments where nutrient deficiencies were overcome. The experiments have not resulted in practical revitalization programmes. Future fertilization of Danish forests may be limited to systems where nutrient extraction is in excess of the carrying capacity of the ecosystem, and presumably where spruce plantations are converted to broadleaved forests. Finally, future events of deposition of acidifying compounds may necessitate counteractive measures.

Distribution of Ca, K, Mg, and P in acid forest soils in plantations of Picea abies—evidence of the base‐pump effect

The vertical distribution of P, and exchangeable Ca, K, and Mg within the soil profile (up to 100 cm depth of the mineral soil) in 57 Norway spruce (Picea abies [L.] Karst.) stands on sandy, acid soils in western Denmark is presented. The importance of the fraction of mineral nutrients found in the organic horizon is evaluated in particular. The O horizons play an important role for Ca. In half of the soils, more than 50% of the exchangeable Ca was found in the O horizon. Furthermore, large average proportions of exchangeable Mg (ca. 40%) and K (ca. 30%) were found in the O horizon. Phosphorus was quite evenly distributed in the mineral soil, but generally most P was extracted from depths below 50 cm. This vertical distribution pattern reflects the function of the “base pump” of forest ecosystems. In the short term, no substantial increase in the pools of available Ca, Mg and K can be expected due to increased rooting depth, as very minute amounts of exchangeable Ca, K and Mg were found in the deeper laye...

Spatio-temporal modeling of the invasive potential of wild boar—a conflict-prone species—using multi-source citizen science data

Denmark was considered not to have an established population of free-ranging wild boar. Today, sporadic observations of wild boar challenge that view. Due to its reservoir role for economic devastating swine diseases, wild boar represents a potential threat for Denmarks position as a large pig- and pork-exporting country. This study assessed the prospects of wild boar invasion in Denmark. Multi-source citizen science data of wild boar observations were integrated into a multi-modelling approach linking habitat suitability models with agent-based, spatially-explicit simulations. We tested whether the currently observed presence of wild boar is due to natural immigration across the Danish-German border, or whether it is more likely that wild boar escaped fenced premises. Five observational data sources served as evaluation data: (1) questionnaires sent to all 1625 registered owners of Danish farm land, located in the 60 parishes closest to the border, (2) an online questionnaire, (3) a mobile web-based GPS application, (4) reports in the media or by governmental agencies, and (5) geo-referenced locations of fenced wild boar populations. Data covering 2008-2013 included 195 observations of wild boar, including 16 observations of breeding sows. The data from the Danish Nature Agency and the mailed questionnaires were consistent regarding the location of wild boar observations, while data from the Danish Veterinary and Food Administration, the media and the electronic questionnaires documented individual scattered observations in the rest of Jutland. Most observations were made in the region bordering Germany. It is uncertain whether the relatively few observations represent an established population. Model outcomes suggested that the origin of wild boar in about half of the area with sporadic observations of wild boar could be attributed to spatial expansions from a local Danish population near the border and consisting of wild boar originally of German origin. However, the other half, located distant to the border, were likely a result of animals escaping fenced premises inside the country. The approach serves as a template to assess the status of an invading species and improve the knowledge base for risk assessment and management decision.

Revitalisation of Common Use in Management of Modern Multifunctional Landscapes

Abstract Land areas in collective ownership or use are traditionally referred to as commons. Through history, the common use and ownership has been a widespread means of regulating the use of natural resources. Changing economic conditions and technology spawned a process however where land use rights and landowner rights aggregated into the modern form of private ownership of individual farms with full management and owner rights. This process had obvious rationales in terms of production of marketable agricultural products. However, in the twentieth century increasing awareness of the supply of externalities such as clean groundwater and recreational opportunities from landscapes turned the attention once again to commons as an instrument for managing natural resources. Using groundwater and coastal landscapes as case examples, we pinpoint problems where outputs from the landscape are multiple consisting of a mix of public and private goods. In some instances central intervention is needed to ensure provision of public goods. In situations where transaction costs are too high to justify the guaranteed supply of goods, local initiatives, cooperatives and networks may be suitable regulatory alternatives to the predominant private and individualised ownership. It is concluded that the management regimes chosen should reflect the dominant functionality of the area in question.

Assessing long-term sustainable environmental impacts of agri-environment schemes on land use

The lack of generic methods to assess the environmental consequences of agricultural practices and the lack of consensus on monitoring and evaluation of environmental, agricultural and socio-economic effects of agri-environment schemes (AES) in EU Member States call for better evaluation methods. The ‘Agri-environmental Footprint’ project proposed to deal with these problems by establishing a new evaluation method, the Agri-Environmental Footprint Index (AFI). The AFI is an index customised to local stakeholder preferences, using expert knowledge for assessment of impacts and sensitivity, and indicators of the environmental state at farm level. In a Danish test case, agricultural practices at twenty-five farms in two groundwater protection zones were assessed. Data was collected from databases, registers, maps and interviews with farmers. The index was calculated for 1996/7 and 2006/7 to track temporal development and effects of entering an agri-environmental scheme. The Danish case demonstrated that the index can be used to track changes in environmental impacts and that entering agri-environmental scheme had a positive impact on the index value. However, the index should be used with caution. It is important to consider the robustness of each indicator: to assess whether changes will occur over time; whether changes are linked to management practices or external factors; and whether data are available up to date. Indicators dependent upon uptake data from agri-environmental schemes should be used with great caution. Retrospective use of stakeholder preferences is subject to uncertainty because preferences may have changed over time.

Functional and Structural Changes of Agricultural Landscapes: How Changes are Conceived by Local Farmers in Two Danish Rural Communities

Abstract The subject of this paper is the views of farmers concerning their local landscape. In two contrasting Danish case study areas previously analysed in the 1990s, a small number of farmers have been interviewed regarding their views of the landscape and recent changes in their respective area including landscape changes. One of the areas (Hvorslev) is characterized by good conditions for agriculture, intensive husbandry production and a relatively stable landscape history. The other (Nees) has more marginal conditions and major changes in land use characterize the recent landscape history. We analyze the way in which the landscape is perceived by farmers and compare their views of the changing landscapes with the actual recorded changes on the one hand, and with other significant changes on the other. Farmers in both areas emphasized the same type of structural changes in agriculture and in the villages as significant, whereas only farmers in Nees indicated that the landscape had changed. When asked to characterize the landscape, farmers in Nees replied with a greater degree of detail and were more locally focused compared to farmers in Hvorslev who mainly referred to (well known) sites located a few kilometres outside the area in question. Long-term experiences with landscape changes and collective actions concerning landscape issues are suggested as the main reasons that farmers in Nees share a well developed awareness of their local landscape. We conclude by discussing some implications of this study for landscape research and policy.

Stability of Norway spruce plantations in western Denmark : soil nutrient aspects

Soil samples from 57 Norway spruce stands on sandy and nutrient poor soils in western Denmark were analysed for their content of exchangeable calcium, potassium and magnesium. The content of the three elements showed a strong spatial variation and the content of Mg and Ca correlated significantly with stand yield class. Estimations on nutrient export by harvest of stem and bark and a comparison with soil content, suggest that severe nutrient deficiencies may occur on many sites in the future. A soil weathering assay applied to selected sites, indicated that the long-term Ca supply is particularly critical, whereas the long-term supply of K and Mg from weathering of soil minerals, is more stable.