EVOLUTION OF SOME SOIL FERTILITY INDICES IN AN AREA AFFECTED BY OIL EXTRACTION AND PIPELINE IMPLANTATION

The Cross-Sector Biodiversity Initiative (CSBI) is a partnership among the International Petroleum Industry Environmental Conservation Association (IPIECA), the International Council on Mining and Metals (ICMM), and the Equator Principles Association, for developing and sharing good practice related to biodiversity in the extractive industries. CSBI has developed products that guide users towards limiting, as far as possible, the negative impacts of development projects on biodiversity, and realizing positive impacts when possible. A cross-sectoral guide for implementing the mitigation hierarchy provides practical guidance to effectively support the operation of the mitigation hierarchy. The mitigation hierarchy is ideally applied from the earliest stages of a new project, or an existing project’s expansion. It is more challenging to apply the mitigation hierarchy retrospectively to a project that is already operational. In this case, the potential for avoidance and minimization is likely to be limited, and the sole opportunity is the natural resilience and auto-mitigation or auto-restoration of the stressed area. The soil resilience to the stress, due to the presence of both a buried oil pipeline and oil wells, and the subsequent natural mitigation, have been monitored for three years (2015-2017) by measuring several chemical and biological parameters, and assessed by means of a discrete series of usually adopted indices. The evolution of soil fertility indices was evaluated taking into account six parameters: percentage of organic matter, basal respiration within 24 hours and cumulative respiration within 28 days, microbial carbon, metabolic quotient and mineralization quotient. The variation of chemical properties was also monitored by annual measurements of soil texture, pH, electrical conductivity, lime content, CEC, total-N, total-S, Olsen-P and exchangeable K.