Native Plant Species as an Alternative to Rehabilitate Iron Ore Waste Piles in Carajás Mineral Province, Brazil

Abstract

ABSTRACT The selection of promising and appropriate plant species and knowledge of their effects on the soil are essential for mineland rehabilitation success. The present study evaluated the effects of three different plant seed cocktails on fertility, soil cover, and erosion control in two iron waste piles in the Carajás Mineral Province, Eastern Amazon, Brazil. The three different seed cocktails were: commercial (only commercial species); native (only species native of Carajás); mixed (native and commercial species); and a control treatment (without seed application). Additionally, tillers from native grasses from Carajás were planted in one of the waste piles. The cocktails were applied by hydroseeding together with fertilizer, mulch, organic compost, and a tackifier. Analyses were performed at 12 and 24 months after the seeding in the waste piles. In general, all cocktails contributed to vegetation establishment, organic matter accumulation, and increased soil fertility. The commercial cocktail stands out due to its ability to improve soil fertility. Native species showed the best cover performance, and less soil loss, highlighting their use for effective control of soil erosion. Thus, native species have the potential for use in rehabilitation projects involving iron waste piles in the Amazon. This is especially relevant because the use of native plant species is mandatory and a declared rehabilitation target.