Nicholas J. Hutchings

Agroecology, scaling and interdisciplinarity

Abstract Based on a review of its history, its present structure and its objective in the future, agroecology is defined as an integrative discipline that includes elements from agronomy, ecology, sociology and economics. Agroecology’s credentials as a separate scientific discipline were measured against the norms of science, defined by Robert King Merton (1973): communalism, universality, disinterestedness, originality and doubt. It is concluded that agroecology meets many of these norms and where it differs, it does so in a way that perhaps anticipates the manner and the direction in which the social position of science is changing. Accepting agroecology as a separate scientific discipline, the two main issues with which it must contend were considered to be those of scaling and interdisciplinarity. Scaling is a problem because results of agroecological research are typically generated at small spatial scales whereas applications are frequently implemented in larger, administrative units. A framework to convey information from science to decision-makers was proposed and tested in a case study of farm energy use. Interdisciplinarity is a problem because researchers from different disciplines see the world from different viewpoints, use different language, work at different locations and use different criteria to evaluate one another’s work. Progress in this area is likely to be slow and driven by the need to justify the value of science to society.

Evaluating nitrogen taxation scenarios using the dynamic whole farm simulation model FASSET

The whole farm model FASSET ver. 1.0 was used for evaluation of the environmental and economic consequences of implementing different nitrogen taxes. The taxation policies analysed were a tax on nitrogen in mineral fertiliser, a tax on nitrogen in mineral fertiliser and imported animal feedstuff, and a tax on the farm nitrogen surplus. In these scenarios, the tax price was equal to the price of the nitrogen in mineral fertilisers (0.67 E kg N 1 ). Four farm types were considered: arable on sandy soil, arable on loamy soil, pig production on sandy soil and pig production on loamy soil. Impacts of the taxes for each farm type on crop rotation, fertiliser use and pig production were estimated by the Linear Programming module of FASSET. The dynamic simulation module of FASSET evaluated the environmental and economic consequences of the new production plans. The social abatement cost of reducing nitrate leaching varied between 1 and 9 E kg N 1 . None of the taxation policies was the most cost-effective for all farm types. Tax on mineral fertiliser favours pig producers, whereas the tax on nitrogen surplus favours arable farms. Thus efficient taxation schemes for reduction of nitrate leaching should differentiate between farm types rather than use uniform input taxes. # 2003 Elsevier Science Ltd. All rights reserved.

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.

Life cycle assessment of pig slurry treatment technologies for nutrient redistribution in Denmark

Animal slurry management is associated with a range of impacts on fossil resource use and the environment. The impacts are greatest when large amounts of nutrient-rich slurry from livestock production cannot be adequately utilised on adjacent land. To facilitate nutrient redistribution, a range of different technologies are available. This study comprised a life cycle assessment of the environmental impacts from handling 1000 kg of pig slurry ex-animal. Application of untreated pig slurry onto adjacent land was compared with using four different treatment technologies to enable nutrient redistribution before land application: (a) separation by mechanical screw press, (b) screw press separation with composting of the solid fraction, (c) separation by decanter centrifuge, and (d) decanter centrifuge separation with ammonia stripping of the liquid fraction. Emissions were determined based on a combination of values derived from the literature and simulations with the Farm-N model for Danish agricultural and climatic conditions. The environmental impact categories assessed were climate change, freshwater eutrophication, marine eutrophication, terrestrial acidification, natural resource use, and soil carbon, nitrogen and phosphorus storage. In all separation scenarios, the liquid fraction was applied to land on the pig-producing (donor) farm and the solid fraction transported to a recipient farm and utilised for crop production. Separation, especially by centrifuge, was found to result in a lower environmental impact potential than application of untreated slurry to adjacent land. Composting and ammonia stripping either slightly increased or slightly decreased the environmental impact potential, depending on the impact category considered. The relative ranking of scenarios did not change after a sensitivity analysis in which coefficients for field emissions of nitrous oxide, ammonia and phosphorus were varied within the range cited in the literature. Therefore, the best technology to implement in a given situation depends on the environmental problem in question, local policy, cost and practicality.

Multifunctional farming, multifunctional landscapes and rural development

The Common European Agricultural Policy (CAP) is under transformation towards a Common Agricultural and Rural Policy of Europe (CARPE). During this transformation, substantial parts of the previously direct support for agricultural production (1st pillar measures) are now decoupled from production. Moreover, a share of direct payments is modulated to the rural development programme, which is the 2nd pillar of the CARPE (Table 1).

A nitrogen budget for Denmark; developments between 1990 and 2010, and prospects for the future

A nitrogen (N) budget for Denmark has been developed for the years 1990 to 2010, describing the inputs and outputs at the national scale and the internal flows between relevant sectors of the economy. Satisfactorily closing the N budgets for some sectors of the economy was not possible, due to missing or contradictory information. The budgets were nevertheless considered sufficiently reliable to quantify the major flows. Agriculture was responsible for the majority of inputs, though fisheries and energy generation also made significant contributions. Agriculture was the main source of N input to the aquatic environment, whereas agriculture, energy generation and transport all contributed to emissions of reactive N gases to the atmosphere. Significant reductions in inputs of reactive N have been achieved during the 20 years, mainly by restricting the use of N for crop production and improving livestock feeding. This reduction has helped reduce nitrate leaching by about half. Measures to limit ammonia emissions from agriculture and mono-nitrogen oxides (NOx) emissions from energy generation and transport, has reduced gaseous emissions of reactive N. Much N flows through the food and feed processing industries and there is a cascade of N through the consumer to solid and liquid waste management systems. The budget was used to frame a discussion of the potential for further reductions in losses of reactive N to the environment. These will include increasing the recycling of N between economic sectors, increasing the need for the assessment of knock-on effects of interventions within the context of the national N cycle.

Modelling the potential of slurry management technologies to reduce the constraints of environmental legislation on pig production

Limits on land applications of slurry nitrogen (N) and phosphorus (P) are used to restrict losses of nutrients caused by livestock production. Here, we used a model to assess technologies that enable a more even geographic distribution of slurry nutrients to land. Technologies included were screw press slurry separation, with or without solid fraction composting, centrifuge separation with or without liquid fraction ammonia (NH3) stripping, and anaerobic digestion. Regulatory constraints were placed first on the application in slurry of N, then P, then N and P both on the producing (donor) and receiving (recipient) farms. Finally, a constraint preventing an increase in donor farm NH3 emissions was imposed. Separation had little effect on N losses per unit mass of slurry, but NH3 stripping led to a reduction. Centrifuge separation allowed a greater increase in pig production than a screw press, especially with P regulation. NH3 stripping was only advantageous with N regulation or when combined with NH3 scrubbing of pig housing ventilation air, when donor farm NH3 emissions were a constraint. There was a production penalty for using composting or anaerobic digestion. The choice of appropriate slurry management option therefore depends on the focus of the regulation. Nuanced and therefore complex regulations are necessary to take advantage of synergies and avoid cross-policy conflicts and incongruencies.

The MEA-Scope Modelling Approach

The MEA-Scope project developed, and applied a modelling approach that allows for the ex ante assessment of sustainability impacts of new policies, technologies and market changes. Thereby, the agricultural production at farm level and its effect on social, economic and environmental assets under changing circumstances is examined. The MEA-Scope modelling approach simulates the development of regional agricultural production structures over time. Within the same analysis, the approach considers details of individual farms and soils. During the project duration, three pre-existing models were further completed and interlinked with each other. The modelling approach was applied at two different levels of detail in seven different European regions to examine the effects of five agricultural policy scenarios. The core models involved were AgriPoliS, MODAM and FASSET/Farm-N. In this chapter, the modelling approach, characteristics of the models involved and the policy scenarios are introduced while results as well as details on the different modelling applications can be found in subsequent chapters of this book.

Ammonia Policy Context and Future Challenges

27.1 Summary Ammonia emissions are major contributors to eutrophication and acidification of ecosystems and secondary PM 2.5 concentrations in Europe. Reduction of the ammonia emissions in Europe has been on the agenda for more than a decade, first on a national scale, e.g. in Denmark and the Netherlands, followed by international efforts. The latter include the UNECE CLRTAP Gothenburg Protocol and EU directives and strategies. This Cross Cutting Group considered the policy context of the ammonia problem, including socio-economic, environmental, institutional and technological aspects. Drawing on the scientific findings and recommendations from the other Working Groups and independent contributions from the participants, the Cross Cutting Group addressed the potential role of different policy options to help mitigate ecosystem and health impacts of ammonia emissions. It also discussed a need to adapt tools used in policy analysis (integrated assessment models, IAMs) and consequently evaluate policies in view of new findings. Ammonia policies are becoming strongly interlinked with a number of other environmental and agricultural policies. In order to avoid the problem of pollution swapping, future policies need to consider these interactions. This in turn calls for extensions the tools currently used, verification of specific elements of the models, adaptation of monitoring networks, targeted measurement programs, but also possible revision of legislation in order to close existing loopholes and increase synergies in addressing nitrogen pollution at large. In that sense, priority should be given to measures aiming at reducing all kinds of nitrogen losses at farm level. Ammonia emission reduction policies must be analysed in a multi-effect (human health, acidification and eutrophication of the ecosystems and related biodiversity loss), multi-media (air, water, soil), multi-scale (hot spots, regional, European, global) framework.

Methane emissions from enteric fermentation as well as nitrogen and volatile solids excretions of German calves – a national approach

Enteric methane emission rates and (renal and faecal) nitrogen and volatile solids excretion rates were calculated using a procedure that reflects the development of the calves’ rumen as well as German national animal performance data and representative diet properties. Standard calves have a birth weight of 41 kg animal-1, a final weight of 125 kg animal-1 and a mean weight gain of 0.67 kg animal-1 d-1. The emission rate of 9.4 kg methane per place and year and the methane conversion rate of 41 kJ MJ-1 exceed those derived from expert judgements currently applied (4.4 kg place-1 a-1 and 20 kJ MJ-1, respectively). These differences are caused by diffe rent weights and weight gains. The newly derived methane emissions and methane conversion rates fall below those obtained from the application of IPCC Tier 2 procedures. Nitrogen excretion rates amount to about 19 kg place-1 a-1. The share of renally excreted nitrogen is 0.64 kg kg-1 rather than 0.60 kg kg-1 provided in the UNECE guidebook. It is common practice to quantify volatile solids release rates according to IPCC guidance documents. However, this procedure had been shown to be inadequate. The results obtained in this work (144 kg place-1 a-1) fall below those assessed with the IPCC methodology (about 500 kg place-1 a-1).