Boron deficiency as a factor in the reclamation by liming of a soil contaminated by mine waste

Mine wastes from a lead-zinc mine have been spread by water action over a flood plain and the deposits are not fully revegetated after a lapse of 40 years. The nutrition of oats, subterranean clover and poplar grown in the contaminated material and in mixtures of it with an uncontaminated control soil was investigated. For all species, high acidity and availability of zinc were principal factors that were counteracted by the application of lime. However, a depression in growth of clover in both soils was observed with high rates of lime. This was subsequently shown to be associated with boron deficiency in both cases. Hence, in the reclamation by liming of contaminated areas, consideration should be given to the inclusion of boron as a nutrient just as it should be when lime is applied to agricultural soils similar to the control soil.