Evaluating the Effect of Bacterial Inoculation and Fertilization on the Soil Nutrient Status of Coal Mine Soil by Growing Soybean (Glycine max) and Shrub Lespedeza (Lespedeza bicolor)

Abstract

Revegetation with fast-growing N-fixing leguminous plants can be an alternate for reclamation of degraded coal mining areas. Selection of appropriate plant species is an important factor in deciding the success in the remediation of mine spoil. Thus, this study was carried out in greenhouse conditions to evaluate the effect of two N-fixing leguminous plant seedlings, soybean (Glycine max) and shrub lespedeza (Lespedeza bicolor), on the available N and other soil nutrients (P, K, Ca, and Mg) of the experimental coal mine soil. Four treatments, including T0—non-fertilized non-inoculation (control), T1—fertilization, T2—bacterial inoculation, and T3—combination of fertilization and bacterial inoculation with three replications were applied to both plants. Concentration of NH4+-N and NO3−-N increased significantly in the soil at different treatments for both soybean and shrub lespedeza, as compared to control, but apart from control no significant difference was observed between other treatments of increased NH4+-N for soybean and increased NO3−-N for shrub lespedeza. The highest number of nodules and dry weight of nodule per plant (g) was recorded 5.73 and 1.8, respectively in soybean, and 7.77 and 2.76, respectively, in shrub lespedeza with bacteria-inoculated treatment (T2), whereas fertilized treatment (T1) produced the lowest number of nodule and dry weight of nodule in both plants. Increasing of available P and K was significantly high when NPK fertilizer was applied to the plants but decreased at other treatments. Therefore, it can be concluded that soybean and shrub lespedeza have a significant role in changing soil nutrient status in coal mining soil through fertilizer application and biological N fixation.