Ameliorative effect of Lantana camara biochar on coal mine spoil and growth of maize (Zea mays)

The aftermath of surface mining is a wasteland deprived of vegetation, soil structure and biodiversity. The unearthed overburden material is nutrient deprived and can only support the growth of invasive weeds such as Lantana camera which often cause allelopathy. The aim of the study is to prepare biochar from these noxious weeds and use it as an amendment for the mine spoil reclamation. Lantana biochar (LB) was prepared and applied to mine spoil, and Zea mays L. growth on biochar amended mine spoil was monitored for three months. Biochar application in a coal mine spoil using LB is comparatively de novo approach for reclamation practitioners. LB was prepared at varying temperature (250, 350 and 450℃) and residence times (30, 45 and 60 min) and characterized. After characterization, the most recalcitrant biochar at 450℃ for 60 min was chosen for application for the study. A pot trial was conducted to study the effect of LB at 0, 5, 10, 20 and 30 g kg⁻¹ dosage on the yield of Zea mays and mine spoil properties. Significant ameliorative effects were observed with increase in organic carbon content (2.9 times), cation exchange capacity (2 times), water holding capacity (0.13 times) and decrease in bulk density (0.5 times) in the mine spoil. The seedling vigour index and germination also increased significantly (p < .05) at 30 g kg⁻¹ biochar treatment compared to control. The study concluded that LB has the potential to remediate coal mine spoils and promote re-vegetation in degraded land.