Environmental Impacts of Agricultural Expansion in Colombia.

Different degrees and types of erosion affect more than 75% of the soils in Colombia. Non-erodible lands are located in marginal ecosystems such as the Colombian Amazonia (natural forests) and Orinoquia (undisturbed savannas), which represent about 50% of the extension of the country. These lands, dominated by Ultisols and Oxisols, provide the last frontier for agricultural expansion in Colombia despite their fertility limitations, the impact of natural erosion agents (e.g. precipitation patterns), and their susceptibility to erosion due to land use change. Results from continuous research oriented to understand and evaluate soil erosion effects on soil productivity in the Piedmont and High Plains of the Orinoquia, and their associated costs, are presented. Field data collection, data analysis and modeling tools were methods used to quantify, assess and predict soil erosion rates; the potential degradation of physical, chemical and biological soil properties; changes in soil and water quality; crop yield variations; and the environmental cost of soil erosion. All the experimental factors were induced by changes in land use and land management. The potential for establishing and maintaining long term sustainable agricultural production in the region is also questioned and discussed.