Energy use in crop production on danish mixed farms: Systems modelling of data from farm studies

Kurzfassung

The problems of balancing agricultural production methods against environmental concern cannot be solved by focusing on single activities of livestock farming and experimental knowledge alone because of interactions between herds and crops and between the production system and the manager. An alternative method based on studies in private farms is proposed to evaluate the effects of the production intensity on pollution and resource efficiency. Energy use and crop yield in gram and grass-clover crops registered on conventional and organic mixed dairy farms were analyzed in order to facilitate modelization of energy efficiency in different production systems on different danish soil types. The energy efficiency was higher in organic crops on all soil types with the smallest difference on irrigated sandy soils. Yields were highest in conventional crops receiving large indirect inputs of energy from fertilizers. The yield response was not sufficient to give the same energy efficiency as in organic crops. Combined with an earlier analysis of nitrogen surplus and efficiency on the same farms the results indicate that high efficiency in use of both nitrogen and energy can be achieved by reducing intensity of production in mixed dairy farming. The need to include the farmers value orientation in the farming systems analysis is discussed.