Soil erosion from agricultural land affects the water quality and environment, as well as soil fertility and agricultural production. In many areas, the economy is centered on this production; therefore, loss of fertility greatly affects the economy of communities and regions as well. In tropical areas, like the eastern savannahs of Colombia, the extreme climate causes the soils to be susceptible to rapidly loose fertility following erosion. Agricultural fields growing soybean, corn, and rice on rotation under three different tillage practices (e.g. conventional tillage, reduced tillage, and direct planting) were studied at the Experimental Station La Libertad (CORPOICA) in Villavicencio, Colombia. Information regarding the climate, crop yield, runoff, sedimentation, and nutrients present in the runoff and eroded materials was collected and compared to the APEX (agricultural policy/environmental extender) model predictions. The overall ability of APEX to model runoff and soil erosion is evaluated in this study, with the nutrient enrichment of eroded material being of particular interest. Following the evaluation of soil erosion, environmental economic accounts will be evaluated to determine the economic impact of erosion and loose of soil fertility in the study area.