Effects of Combined Application of Coal-Based Charcoal and Organic Fertilizer on Soil Properties and Plant Growth in Desertified Soils

Desertified soils severely limit vegetation restoration and sustainable land use in arid regions. This study aims to evaluate the individual and combined effects of coal-based charcoal produced by coal pyrolysis and organic fertilizer on soil properties and the growth performance of Amorpha fruticosa L. A pot experiment was conducted using degraded sandy soil collected from Inner Mongolia, with amendment rates of 2.5%, 5%, and 10% (w/w) for each material, and a combined treatment (2.5% coal-based charcoal + 2.5% organic fertilizer). The results showed that all treatments reduced soil bulk density (BD) and increased electrical conductivity and nutrient availability. Application of coal-based charcoal increased soil pH, whereas organic fertilizer decreased it, and their combined application resulted in a more balanced soil pH. The combined treatment (FT) achieved the highest germination rate (83.33%), significantly improved root morphological traits, enhanced chlorophyll content and the photosynthetic rate, and increased peroxidase, superoxide dismutase, and catalase activities, while reducing malondialdehyde content. These findings suggest that combining coal-based charcoal with organic fertilizer provides complementary benefits, enhancing soil physicochemical properties and plant physiological performance, thereby promoting the growth of A. fruticosa L. and providing an effective strategy for restoring desertified soils.