Soil conditioners improve the environment for grass growth in iron mining tailings of the Fundão dam failure

• Published in: Ciência e agrotecnologia 2024-01, Vol.48
• Main Authors: Borges, Pedro Henrique de Castro, Silva, Aline Oliveira, Santos, Jessé Valentim dos, Carvalho, André Mundstock Xavier de, Carneiro, Marco Aurélio Carbone, Siqueira, José Oswaldo
• Format: Article
• Language: English
• Subjects: AGRICULTURE, MULTIDISCIPLINARY; environmental impact; soil rehabilitation; Technosol; vermiculite
• ISSN: 1413-7054; 1981-1829; 1981-1829
• DOI: 10.1590/1413-7054202448002724

ABSTRACT Areas impacted by the deposition of iron mining tailings present physical and chemical characteristics that can hinder root growth, and applying soil conditioners can help alleviate these limitations. The objective was to evaluate the effect of soil conditioners in improving the environment for the growth of grass in soil affected by iron mining tailing. Four different experiments were conducted testing conditioner proportions (0, 5, 10, 25, and 50% v/v), in a completely randomized design with four replications, using Cynodon spp. The conditioners were sand, vermiculite, sawdust, and organic compost. Bulk density, macro- and microporosity, total pore volume (VTP), pH, organic matter content (OM), cation exchange capacity (CEC), and dry mass of the aboveground, root, and total plant were evaluated. There were improvements in porosity and a reduction in density with the application of vermiculite, sawdust, and organic compost; however, sand decreased the VTP. The pH was reduced with sawdust and increased with compost. Sawdust and compost increased OM. CEC increased with vermiculite and compost. The sand and vermiculite conditioners promoted the greatest growth of Cynodon spp., with emphasis on vermiculite, which provided the greatest increases in plant biomass production. The soil conditioners, overall, proved effective in improving porosity conditions, reducing density, increasing OM, and promoting plant growth, this makes this technology efficient for application in tailings. Due to its notable effect on increasing biomass and improving the environment for grass growth, vermiculite can be recommended for rehabilitation environments impacted by iron mining tailings or for post-mining revegetation. RESUMO Áreas impactadas pela deposição de rejeito de mineração de ferro possuem características físicas e químicas que podem dificultar o crescimento das raízes, e a aplicação de condicionadores pode ajudar a aliviar essas limitações. O objetivo foi avaliar o efeito de condicionadores de solo na melhoria do ambiente para o crescimento de gramínea em solo afetado por rejeitos de mineração de ferro. Foram realizados quatro experimentos testando proporções de condicionador (0, 5, 10, 25 e 50% v/v), em delineamento inteiramente casualizado com quatro repetições, utilizando Cynodon spp. Os condicionadores foram areia, vermiculita, serragem e composto orgânico. Foram avaliados densidade aparente, macro- e microporosidade, volume total de poros (VTP), pH, matéri