Carbon sequestration in slopes revegetated with bioengineering techniques

摘要

This study evaluates the amount of organic carbon accumulated in the superficial soil layer of slopes that were revegetated 10 years ago, using four different bioengineering techniques. These techniques consisted of soil revegetation: (ⅰ) covered with mulches of ground guinea grass (Panicum maximum); (ⅱ) covered with geotextiles (Rolled Erosion Control Products - RECP) made of guinea grass tied with agave - Vegetal Screen ARP-430; (ⅲ) covered with ground guinea grass three-dimensionally tied with cotton strings; (ⅳ) with no cover. Samples of soil (0 to 20cm of depth) were collected from three slope elevations (2.5m, 5.0m and 7.5m). Control samples were collected from a slope that had not been revegetated. The amount of organic carbon was determined by subtracting the inorganic carbon content from the total carbon content, obtained using the ferrous sulfate titration method. Based on the concept of carbon sequestration, the determined amounts of organic carbon were converted into carbon dioxide. The conversion allowed the estimation of monetary potential of accumulated carbon. Based on the Chicago Climate Exchange rates for carbon sequestration of May 12, 2009, carbon sequestration potential of the applied bioengineering techniques reached up to US$ 2.070/R$ 4.347 per hectare of revegetated slope. Considering the established monetary potential, this paper proposes the development of projects that would enable the commercialization of carbon credits to be used for soil conservation and for native vegetation activities.