Estimación biofísica de efectos ambientales en agua, bajo diferentes escenarios de intensificación en sistemas agropecuarios

Doctoral thesis abstract

Abstract

Estimations indicate an increase in the food production by the 2050, of which around 50% will occur in developing countries. In turn, it has been shown that the global area dedicated to irrigated crops has had an increasing trend of 1.3% per year, and also the milk production has been increasing with an average of 2.2%. Therefore, from the production side, greater pressure is expected on the natural resources that support it, and in particularly, it has been argued that there will be a great limitation to the fresh water accessibility, and, an enormous pressure on the water quality given the increasing pollution. In this way, and given the role that agricultural and livestock systems play in the Uruguayan economy, emphasis has been placed on the long-term sustainability of this resource (among others). Therefore, the general objective of the work was to make an environmental biophysical estimation of certain variables: water footprint, ecotoxicity in water and eutrophication potential, in agricultural and livestock systems under different scenarios of productive intensification. In particular, it was analized two contrasting cases of agricultural intensification: an agricultural system of grains with and without irrigation; and dairy systems under different management strategies. For this, blue water footprint, ecotoxicity, nutrient balance and eutrophication potential models were applied for six farms - rainfed and irrigated soybean and maize production, and for 277 dairy systems. Despite the observed trend, there were no statistical differences between the irrigation and rainfed technologies for grain systems technologies. Although, soybean production had greater repercussions than the corn production due to the insecticides used. On the other hand, greater environmental impacts per hectare were observed as the productive levels of the dairy farms increased, however, this was not presented in a linear way given the quantity and type of inputs used, and because the proportion of pastures and concentrates to feed the livestock that’s tilts the balance in favour or against the quality of the water. Finally, the use of indices constructed from certain environmental indicators turned out to be a useful tool to evaluate impacts considering the different trade-offs involved.