Approach to the assessment of sustainability in organic livestock farms in a Colombian Andean region

Summary

This study aimed to compare conventional livestock production systems in relation to other forms that implement ecological production, evaluating environmental variables (in water: nitrite, nitrate, phosphate, pH and availability of oxygen using photometrics methods and Winkler modified method. In soils: counts of bacteria and fungi using MPN method, and physicochemical properties. In meadows: Prairie composition, quantity and density of arthropods), productive variables (in forages: biomass estimation using the methodology by Campbell and Arnold, nutritional quality using bromatology methods, in animals: milk production, weight gain, and carrying capacity), and economic variables (Fertilization cost and control ecto-endo parasites cost) in 6 farms Township Guayabal de Síquima (Colombia). Three of them were classified as conventional while other three farms were classified as ecological in relation with management. The variables were compared statistically using T-test. The work established effects of conventional systems on water quality, significant differences were found between the affluent and effluent water for variables such as pH (P = 0.046), nitrate NO3-N (P = 0.027), and phosphorus as PO43- (P = 0.000). In the ecological management systems, the values associated with nitrate as NO3-N and phosphorus in the effluent water decreased and increased available oxygen. Regarding the microbiological analysis of soil found in most bacteria counts made for ecological systems being found significant difference (P = 0.003) compared to the conventional system as well as many fungi although there was no statistical difference between the two systems. The botanical composition of grasslands showed highly significant difference (P = 0.000) for the amount of grass being higher in organic farms than in conventional and the amount of weed (P = 0.000) being higher on conventional farms. Forage production per year was higher in conventional farms, enabling higher carrying capacity on them but not significant difference between the systems. The development of silvopastoral systems in the ecological farms, allowed the incorporation of various species in the animal feed, and probably influenced the diversity of arthropods in the meadow, along with other practices that additionally favored an integrated pest management. An evaluation of 12 indicators related with sustainability evidenced the best results in ecological systems.