Spectral and Soil Quality Index for Monitoring Environmental Rehabilitation and Soil Carbon Stock in an Amazonian Sandstone Mine

Paula Godinho Ribeiro,Pedro Walfir Martins E Souza Filho,Markus Gastauer,Cecílio Frois Caldeira Júnior,Diogo Corrêa Santos,Rafael Borges Da Silva Valadares,Rosane Barbosa Lopes Cavalcante,Guilherme Oliveira,Douglas Silva Dos Santos,Marco Aurélio Carbone Carneiro,Wilson Da Rocha Nascimento Junior,Gabriel Caixeta Martins,Silvio Junio Ramos,Ediu Carlos Da Silva Junior

doi:10.3390/su14020597

Paula Godinho Ribeiro, Pedro Walfir Martins E Souza Filho + Show 12 more

Open Access

https://doi.org/10.3390/su14020597

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Abstract

Rehabilitation is the key factor for improving soil quality and soil carbon stock after mining operations. Monitoring is necessary to evaluate the progress of rehabilitation and its success, but the use of repeated field surveys is costly and time-consuming at a large scale. This study aimed to monitor the environmental/soil rehabilitation process of an Amazonian sandstone mine by applying spectral indices for predicting soil organic carbon (SOC) stock and comparing them to soil quality index. The studied area has different chronological rehabilitation stages: initial, intermediate, and advanced with 2, 10, and 12 years of onset rehabilitation activities, respectively. Non-rehabilitated (NR) and two native forest areas (RA) were used as controls. Soil samples were analyzed for physical, chemical, and biological attributes. After determination of Normalized Difference Vegetation Index and Bare Soil Index, simple regression analysis comparing these indices with SOC stock showed a good fit (R2 = 0.82). Rehabilitated areas presented higher soil quality index (~1.50-fold) and SOC stock (~10.6-fold) than NR; however, they did not differ of RA. The use of spectral indices was effective for monitoring the soil quality in this study, with a positive correlation between the predicted SOC stock and the calculated soil quality index.

Highlights

Introduction iationsThe rehabilitation of mining areas in Brazil is regulated by several resolutions and normative instructions [1]
An increase of Normalized Difference Vegetation Index (NDVI) values and a decrease of Bare Soil Index (BSI) values were observed following the chronosequences of environmental recovery (Figure 3)
Differences in non-rehabilitated and rehabilitated areas can be evidenced by the soil cover and soil attributes such as CEC, soil organic matter (SOM), and the soil organic carbon (SOC) stock

Summary

Introduction

Introduction iationsThe rehabilitation of mining areas in Brazil is regulated by several resolutions and normative instructions [1]. The mining companies should promote the return of the degraded area to an appropriate biological state. In this sense, revegetation is a technique widely used as it is the key factor for improving sustainability, increasing soil quality, and storing soil organic carbon [2]. Revegetation is a technique widely used as it is the key factor for improving sustainability, increasing soil quality, and storing soil organic carbon [2] This process is favored in Brazil due to the broad native species diversity and favorable climatic conditions for plant growth [3]. Monitoring the areas, especially in a chronosequence study, is necessary to understand whether the adopted rehabilitation practices are contributing to the improvement of soil attributes and the rehabilitation of the disturbed area [6,7]

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