6. Conclusions
Although, sustainability is recognized as an essential element to guarantee the socio-cultural, ecological and economic viability of the systems of agricultural production, its implementation requires evaluation of methodologies, that provide useful information about the current state of the interventions over the ecosystems, the intensity and the direction of the possible changes of each production system.
When understanding sustainability as a goal to reach throughout time, it is necessary to consider a historical perspective to analyze the degree of sustainability of the ways of management and organization of the agricultural productive systems, trying to establish the higher or lower degree of sustainability among them, to guide decision making toward production patterns and consumption that is less impacting on nature, because it is the changes on social metabolism that can make a system more sustainable in time.
For the evaluation of agricultural sustainability, balances of matter and energy, the hemeroby, rural metabolism, the balance of nutrients and human appropriation of the net primary production, have been used, among others that should be employed with a critical vision, since its construction process is associated to a great uncertainty. Each methodology of evaluation analyzes different aspects (energy, money, materials, and resources) it is for that reason that it suggests the analytical triangulation to consider various methods of analysis.
It is recognized that the methodologies described, are an important step toward the construction of more sustainable agricultural production. However, more integral methodologies are required that deal with the social, ecological and economic dimension of sustainability and that reduce the linearity of the current ones.
