Using Mine Tailings as a Soil Improver to Reduce Micronutrient Deficiencies in Wheat Crops, Western Morocco

Micronutrient deficiencies in agricultural soils significantly affect crop productivity and the nutritional quality of produce, posing potential risks to human health. Abandoned mine tailings, which are rich in micronutrients, can serve as an effective solution to enhance the nutritional value of crops while also mitigating environmental impact. In this study, the soils were sourced from the semi-arid Doukkala region in western Morocco, while the tailings were obtained from the abandoned Kettara mine in the nearby Marrakech region. This study assessed the biomass and bioconcentration of wheat (Triticum aestivum L.) grown in three different soils amended with treated mine tailings (TMT) at doses of 0, 0.2, 1, 2, and 4 g·kg-1. The experiment, conducted under greenhouse conditions and in pots, employed a split-plot design with three replicates, monitoring morphological parameters and plant biomass. Concentrations of Cu, Fe, Zn, and Mn in wheat grains were measured by inductively coupled plasma-atomic emission spectrometry (ICP AES) after harvest. The results indicate an increase in root length, shoot height, number of tillers, shoot biomass and grain biomass with TMT amendment doses of less than 1 g.kg-1 soil, by 13.6, 42.1, 42.6, 49.6, and 32.9% respectively. However, these parameters decreased with doses > 2 g·kg-1. Significant linear correlations were observed between the concentrations of micronutrients in wheat grains and those present in the soil. The bioconcentration factor increased but remained below 1. This research reveals that TMT are perfectly suitable to fertilize wheat using doses<1 g·kg-1, ensuring safe application for the environment and human health. Through this research, it was demonstrated that within certain thresholds, TMT can enhance the mineral nutrition of plants as well as positively impact agricultural productivity and product quality. These results can be replicated in other regions worldwide by adhering to the described procedure.