N fertilization did not raise soil greenhouse gas emissions in a reforested reclaimed-mine site over a short-term study

Bauxite mining is a human activity that can have drastic effects on the soil environment, altering its physical, chemical, and biological properties. To improve water and nutrient retention, microbiological activity, and environmental service, it is essential to recover and maintain soil organic carbon stocks. Reforesting reclaimed mine sites and fertilization are two strategies that can be used to eliminate nutrient limitation and accelerate biomass production and soil C sequestration. In this study, we investigated the secondary impacts of nitrogen (N) fertilization on greenhouse gas emissions, microbial community, and total phospholipid fatty acid analysis over a 17-day period at a reclaimed mine site in Brazil. Three forest species compositions were tested: only Eucalyptus, only Anadenanthera peregrina, and a mixture of 16 native forest species collected in fragments of Atlantic Forest. Our short-term observation did not reveal any significant effects of short-term N fertilization on greenhouse gas (GHG) emissions, total phospholipid fatty acid analysis, or the relative abundance of the microbial community. These initial short-term results were favorable for acceptance of the N fertilization recommendation for stimulating biomass regeneration in reclaimed mine sites because there were no negative impacts on environmental quality indexes, such as GHG fluxes. However, longer-term experiments are necessary to better understand the environmental costs and benefits of long-term N fertilization practices associated with reclaimed sites and confirm its recommendation.