Revista de Investigación Agraria y Ambiental

7-17

Authors: Reinaldo Giraldo Díaz & Francis Liliana Valencia T.

This study focuses on Assessment of Environmental Sustainability in Three systems of agricultural production: Conventional, Agroecological and Transition to Agroecological. The conventional system is a system that uses chemical supplies such as herbicides, insecticides and pesticides, heavy machinery such as tractors and irrigation, and emphasis on agriculture as a business. The Transition to Agroecology systems is in the process of conversion from conventional to agro-ecological technology. In the Agroecological farming systems there is a strong human-nature relationship. Studies of Sustainability of production systems are a valuable tool to determine the impact of agro-ecological technologies and identify weaknesses in systems that threaten their sustainability in the short, medium and long term. They allow fast and continuous monitoring within systems, which facilitates their assessment, monitoring and improvement. For the assessment of environmental sustainability the methodology known as Framework for Assessment of Natural Resources Systems was adopted, incorporating sustainability indicator(MESMIS). The attributes evaluated were productivity, adaptability, resilience, self-management, reliability and stability. The agro-ecological production system is environmentally more sustainable than conventional production and transition to agro-ecological systems, because this production system emphasizes the conservation of natural resources, preservation of biodiversity, the use of biological supplies for control of pests and diseases and there is an interaction between man and nature that is not mediated by agro-productivity but respect for the cycles, rhythms and rhythms of nature, forming a biologically diverse landscape and rich in singularities.

29-49

Authors: José A. Acevedo Suárez, Martha I. Gómez Acosta, Teresita López Joy, Ana Julia Acevedo Urquiaga & Yinef Pardillo Baez

Case studies and modeling of logistics systems are the basis for the formulation of the content and structure of a reference model for the organization and management of Value Networks as a higher stage of integrated development of supply chains. The definition of a mathematical model for the balance of the Value Network can reveal the characteristics and principles of organization and management of Value Networks. The instrument obtained enables supply chains to assess their level of development and identify the characteristics that should be developed to reach the concept of Value Network, which is based on knowledge development and environmental integration as supports of the same and its competitive position in the global market. Proper integration into the model of environmental factors ensures that Value Networks are inserted into the objectives of promoting sustainable development. The current concept of logistics flow is extended to incorporate within it the exchange of energy, resources and impacts to the environment. The research methods used were based on a combination of study and experimentation of cases and the conceptual and mathematical modeling of systems.

65-75

Authors: Luis Miguel Borrás S., Guillermo Alfredo Galindo S. & Wilson Triviño Gíl

The patterns of current land use in the Rabanal paramo suggest a slow and progressive deterioration of the vegetation of this ecosystem, probably due to the current practice of disturbances imposed apparently largely by human causes, mainly the expansion of the agricultural frontier (mechanized potato crops) and grazing. The typical situation of the pattern of occupation and land-holding in these places, as well as the established production system, is the starting point to determine its effect on this sector of the Rabanal paramo ecosystem and define whether or not this fact is crucial to its conservation and management. The study was conducted in three stages that included the characterization of the area done through surveys, a review of primary and secondary education, followed by field work, and final tabulation of information. The present study obtained results which were intended to contribute to the knowledge of current land use in a sector of the settlement of San Antonio - Township Guachetá, bordering the Rabanal Paramo and with this give the necessary foundation for understanding how anthropogenic intervention operates in the area and its implications for vegetation dynamics and knowledge of its production systems.

7-15

Authors: Carlos Patiño Torres

Allelic diversity is a fundamental requirement for successful plant breeding programs. When gene pool is limited, several mechanisms are available for variability enrichment, for example, obtaining somaclonal variants through in vitro techniques. Somaclonal variation is a natural phenomenon that occurs in the procedures of plant tissue culture, through is possible to recover mutants with or without adaptive advantages. When this phenomenon is used to generate mutants with specific traits, through the use of an agent of artificial selection, the process is called in vitro selection. When looking for generating plant material that is resistant/tolerant to diseases, the agent of choice may be the causative organism, its parts, or its metabolic products, including toxins. Considerations of cost, simplicity and efficiency, make this technique particularly suitable for developing countries. In this paper, we review the scientific basis underpinning this method.

25-29

Authors: Liliana Valencia-Trujillo, Jaime Restrepo-Paredes, Danny Enrique Cerón-Hernández & Wilmer Ferney Herrera-García

We compared digestibility by testing five different proportions of two low-nourishing species: King Grass (Pennisetum hybridum) and the shrub known as “Resuscitado” (Malvaviscus arboreus Cav.). We fed those to 15 African male sheep, of approximately 20 kg and one year old. We determined the digestibility of the forages in five treatments through Anova analysis and a comparison of the entire digestible nutrients (NDT) with Duncan’s multiple range test. P. hybridum was the forage with better digestibility and the treatments with diverse portions of two forages including this species. It has agreater bioavailability of the main nutrients and the highest percentage of total digestible nutrients present in this grass. Our results are usefulto make decisions about whether or not to cultivate these forage speices to use them as food for ruminants.