Metodologías para la evaluación de sistemas agropecuarios. Parte I. Generalidades. Análisis del ciclo de vida (ACV) y de las redes ecológicas (ENA) Methodologies for evaluating farming systems. Part I. Generalities. Life cycle analysis (LCA) and ecological network analysis (ENA)

The objective of this paper is to provide the general bases for a group of internationally available methodologies, used for the dynamic evaluation of production systems. After an analysis of key concepts related to the system approach, the methodologies are presented (in two successive works): life cycle analysis (LCA), ecological network analysis (ENA), integral energy efficiency (EMERGY) and system trajectory; as well as an example of the application of some of their principles in the construction of an integral evaluation model of farming systems (called GAMEDE). For each of the methodologies, the overall principles and bases for their successful application are described, as well as the objectives, the kind of analyses possible to be carried out, and the keys for the correct utilization and interpretation of the results. References were used that provided concrete examples, illustrating the use of the methodologies that were succinctly described. Each of the sections of the paper attempts to contextualize the main elements to be taken into consideration in the selection of the most adequate methodology to carry out a certain study, its dependence on the nature of the stated objectives, as well as the eventual possibilities of combining one or more methodologies in the same analysis framework.