Moreover, farmers monocrop coca so as to maximize output and allow for easy harvesting, leaving the fragile soil exposed to constant sunshine. Multiple annual harvests on the steep terrain exacerbate soil erosion, and improper use of chemical fertilizers causes water contamination. Finally, clandestine processing of coca leaf into cocaine paste involves a series of toxic chemicals that are causing further environmental pollution. This environmental degradation is in stark contrast to the experience of coca growers in the Yungas of Bolivia, where coca is grown legally. Here, as well as in other regions in Peru and Bolivia, coca is produced for licit domestic and international markets, including pharmaceutical cocaine and flavor extracts used in Coca Cola and a handful of other products.
Farmers often remain on one plot of land for decades.
Their cultivation techniques include growing large leafy plants around coca bushes to protect the soil from the sun, planting the bushes in deep pits to allow for the formation of sturdier root structures, and constructing stone terraces to allow for harvesting on level terrain. These practices, common centuries ago, are rare today because most cultivation is clandestine. Of additional concern are recent news reports of U.S. involvement in developing biologically-designed fungi to wipe out coca. These virulent fungi pose the same ethical and environmental hazards as any other form of biological warfare. In addition, there are reports that the Colombian government has been clandestinely testing tebuthiuron, and the U.S. has been pressuring Colombia to use this granular herbicide in eradication programs.