Jaime Forero-Álvarez’s research while affiliated with Pontifical Xavierian University and other places

Population size and per capita food consumption are assumed to be the two greatest drivers of global environmental change. The intensification of agriculture for food and fiber production, and specially, for energy crops, affects ecosystems due to the use of limited soil resources (e.g. nitrogen, phosphorus, potassium and other macronutrients and micronutrients) which are necessary for their functioning, the release of pesticides, and the conversion of natural ecosystems. However, the location and extent of intensive agriculture and its associated ecological impacts within tropical countries is often well unknown. The purpose of this study is to provide an understanding of the fertilisation practices associated to the phase of sugarcane industrialization in an inter-Andean valley in Colombia. Changes in the nitrogen (N), phosphorus (P) and potassium (K) fluxes were calculated over time (1943, 1984, 1998 and 2010) by using the concept of social metabolism. We applied a nutrient balance model, which was especially created for past agroecosystems (historical studies). The N balances were positive and oscillated between 108 and 98 kg N ha−1 year−1, with a relatively low N use efficiency (about 63% and 42% for 1943 and 2010, respectively). The main inputs were chemical fertilisation and irrigation, and the main outputs of N included harvested N and leaching due to low N use efficiency and high irrigation flows. By 2010, values of atmospheric deposition rose up to 35.6 kg N ha−1 year−1, mainly because the nitrate concentrations in rain water were very high in comparison to previous decades. The K and P balances were positive and near zero, which represents an adequate management according to local conditions.

Based on the authors' own research, and on a review of literature on the subject, we propose a conceptualization of two types of family farming, peasants and capitalized non-peasants family farmers. The focus is placed on partial monetization of the production model. The existence of a monetary and a non-monetary dimension is the key to explaining the economic rationality of these two production models. As a way of explaining the economic efficiency of family farmers, the article concludes with a new conceptualization, which is of micro scale economies. This concept takes up the ideas of other authors who asserted that small-scale farming is more efficient than large-scale farming. It then moves on, and away from this idea by proposing that both large and small-scale farmers can be efficient; the former by virtue of scale economies, and the latter by obtaining scale micro-economies.