A mathematical approach to comparing environmental and economic goals in dairy farming: Identifying strategic development options

Instead of continuously adapting current dairy farming systems according to the ruling legal instruments, exploring strategic development options for the farming system with a focus on the final environmental goals may provide better perspectives for farm continuation. To identify promising options, the dairy farming model was developed. The model describes options of different intensities for producing feed in the field, for processing or buying feed and for converting feed into milk. The combinations of different intensities result in different types of income levels, different nutrient emissions into the ecosystem and different abilities to manage the landscape. The model reconciles economic objectives (maximizing income per ha) with ecological objectives (minimizing nutrient leakages and maximizing landscape values). The multiple-objective model is in turn fed by other models, such as technical coefficient generators for grass, maize and fodder beets. The dairy farming model is applied to assess the type of farming systems that meet environmental policy objectives and analyse the perspectives of dairy farming on sandy soils in the Netherlands. It is shown that many different dairy farming systems are possible meeting the environmental goals (maximum 34 kg N leached, 30 kg N volatilized and a P surplus below 2.2 kg ha), with a range in environmental and economic performance. The scenario selected depends on the preference of the stakeholder. General characteristics are low N application rates on grazed grassland, associated with the restriction on nitrate leaching, animals housed in low-emission stables, associated with the restriction on ammonia volatilization, and a substantial part of the concentrates produced in the region, associated with the restriction on P surplus. Production and utilization of hay is an option to reduce N excretion by the animals. Regional or on-farm concentrate production is economically only attractive if land is in surplus under pressure of environmental goals.