Result of reclamation of man-made dumps from phosphorite deposits in the semi-desert zone of Kazakhstan

Abstract

Pollution from industrial activities, including heavy metal contamination, poses severe environmental challenges, especially in industrialized regions. This study evaluates reclamation efforts at the Kokzhon phosphorite deposit in Kazakhstan’s semi-desert zone, where over 67 million tons of industrial waste have accumulated across 3.3 thousand hectares. Reclamation efforts encompassed the treatment of 6,400 hectares using carbamide amendments and the planting of resilient phytomeliorants, including Russian Olive, Black Saxaul, Androsov Elm, and Salt Cedar. While tree survival rates were low (11%), herbaceous vegetation achieved remarkable success, with legumes and cereals attaining 95% growth rates. Herbaceous productivity increased from 2,200 kg/ha in 2013 to 3,300 kg/ha in 2018, alongside vegetation cover expanding from 60% to 80%. Soil fertility also improved significantly, with humus content rising from 0.18% in 2012 to 1.14% in 2023. Despite these improvements, the long-term impacts of industrial phosphorite mining continue to challenge ecosystem recovery. Over a 12-year period, reductions in humus content (47.6%) and herbaceous productivity (28.4%) have been observed, highlighting the need for enhanced soil management strategies to sustain reclamation outcomes. The results emphasize the potential of biological reclamation to restore degraded semi-desert ecosystems while underscoring the necessity of scalable, cost-effective solutions and long-term monitoring to mitigate ongoing environmental damage.