Succession law of reclaimed soil and vegetation on opencast coal mine dump of loess area

Abstract: Loess Plateau is one of the typical opencast coal mining areas in China with its broken topography, loose soil structure, and destroyed natural vegetation, and the ecological environment is fragile in this area. Coal mining has formed a large waste dump, which had imposed great damage on the surface of the landscape. It not only occupied a large amount of land, but also influenced the animal and plant development; it is a serious threat to the ecological environment. Reconstruction of the damaged soil and vegetation is the key to ecological restoration in the mining area, and the process of vegetation restoration actually is an interaction process of a complex ecosystem between vegetation and soil. The typical plot survey method was used to analyze the dynamic succession law of soil environmental factors and vegetation biomass with reclamation years (3, 5, 10, 12 and 17a) in the Shanxi Antaibao opencast coal mine dump. A logistic succession model of reclaimed soil environmental factors and vegetation biomass land arbor forest in the Loess area opencast mine dump were constructed in this study, and the interactions of partial differential equations between soil and vegetation were built. The results indicated as follows: (1) soil organic matter, total nitrogen, available P, and available K had an S-shaped (logistic curve) increasing with reclamation years and soil bulk density gradually decreased. (2) Using SPSS software to fit the equation model, the correlation coefficients of the models were high and the significance tests were less than 0.05, the soil environment factor models and the arbor vegetation biomass model in the reclaimed land was effective, and the dynamic character of the soil factor and vegetation biomass could be well reflected. (3) All reclaimed soil environmental factors (organic matter, total nitrogen, available P, available K, and soil bulk density) gradually closed to those of the original landscape and gradually become stable with reclamation years. Soil environmental factors play a key role in the restoration process of vegetation, and the stabilizing process of soil environmental factors also was the process of vegetation growth which tended to stabilize. The vegetation volume gradually increased with reclamation years under the influence of the soil environmental factors, and which also had a logistic growth trend. The logistic model of arbor vegetation biomass fit well and can reflect the dynamic succession law of arbor vegetation biomass. The organic matter and total nitrogen are the main factors to influence the biomass of vegetation. (4) Interaction between soil and vegetation was significant, and it fitted the Kolmogorov predator-prey model. The relationship between them can be expressed by a partial differential equations model. This research can provide theoretical basis for land reclamation and ecological restoration in the loess area of an opencast coal mine.