Positive Effect of Ecological Restoration with Fabaceous Species on Microbial Activities of Former Guyanese Mining Sites

Abstract

Understanding ecological trajectories after mine site rehabilitation is essential to develop relevant protocols adapted for gold mining sites. This study describes the influence of a range of mine site rehabilitation and revegetation protocols on soil physicochemical parameters and microbial activities related to carbon, nitrogen and phosphorus cycles. We sampled soil from six rehabilitated mining sites in French Guiana with different plant cover (herbaceous, Cyperaceous, monoculture of Clitoria racemosa and Acacia mangium and association of C. racemosa and A. mangium). We measured the mineralization potential of organic matter by estimating the mineralization of carbon, nitrogen and phosphorus and the microbial catabolic diversity balance. The results showed an improvement in the quality of organic matter on revegetated sites with tree cover. On restored sites with fabaceous species, the microbial biomass is three times higher than non-restored sites, improving the rates of organic matter mineralization and restoring the catabolic diversity to the level of natural Guyanese soils. These results confirm that the establishment of fabaceous species under controlled conditions significantly improves the restoration of microbial communities in mining soils.

El árbol Acacia mangium (Fabaceae) facilita la recuperación de áreas mineras en la selva lluviosa del Chocó, Colombia

“…El mayor contenido de N observado en los suelos mineros revegetados con A. mangium puede deberse a la capacidad que tiene esta especie, al igual que otras leguminosas, de asociarse simbióticamente con microrganismo edáficos (bacterias nitrificantes) que fijan nitrógeno atmosférico (N 2 ) y lo convierten en amonio (NH 4 ), nitratos (NO 3 ) y nitratos (NO 2 ) (Wibisono et al, 2015). Además de la fijación de N 2 , las siembras de A. mangium generan y acumulan cantidades considerables de hojarasca sobre el suelo (entre 6.94 y 8.94 t de hojarasca ha-1 año-1 con una acumulación de 6.64 t ha-1 ; Hero & Watanabe, 2000;Tsai, 1998), la cual, al descomponerse, contribuye a aumentar la retención de agua y la biomasa microbiana del suelo; así como la disponibilidad de materia orgánica, fósforo (P) y N por mineralización de los compuestos de origen vegetal (Bachega et al, 2016;Couic et al, 2022;Voigtlaender et al, 2012;Xiong et al, 2008). Los altos valores de producción de hojarasca y de retorno potencial de nutrientes que ocurren en las siembras de A. mangium, muestran que esta especie tiene un potencial para la recuperación de suelos degradados, a partir del restablecimiento temprano de los ciclos biogeoquímicos (Castellanos & León, 2010).…”

Effect of vegetation blanket cover with different materials on soil microbial community structure of opencast coal mines in arid areas

“…Chang et al (2022) found that a vegetation restoration model for opencast coal mines on the Loess Plateau had a significant effect on the alpha diversity of microbial communities. Couic et al (2022) found that legumes under controlled conditions could significantly improve the recovery of microbial communities in mining soils. Mine reclamation techniques primarily focus on artificial vegetation restoration and soil physicochemical‐biological property improvement (Cao et al, 2020).…”