| Fujian province, which has abandon mineral resources, is the main mining area of southern China. Recent years, People's demand for mineral resources is increasing and the exploration of mineral resources is increasing sharply, thus different kinds of mining wastelands form. The large number of mining wastelands did not only damage vegetation and land, cause soil erosion, but also lead severe damage to the ecological environment. Therefore, how to carry out the vegetation restoration and reconstruction on mining wastelands in Fujian has been the major issue for environmental academic circles to resolve currently.Nowadays, although some scholars had carried out some research on ecological restoration on the mining wastelands in Fujian, the revegetation techniques about the different kinds of mining wastelands of Fujian were still deficiency because of the long-term regardless. This lead to the blindness while carrying out the ecological restoration on mining wasteland in Fujian.Aim to the problems mentioned above, based on the all-round tread check, through outdoor investigation and laboratory analysis, this study took the wastelands of gold-copper mine, coal mine, limestone mine, kaolin mine and rare earth mine as objects to do the revegetaion research. The plant coverage, species diversity, biomass, soil water-stable aggregate, soil nutrient, heavy metals and soil erosion of the different revegetation ages on these mining wastelands were detemined. The revegetation effects and succession rules of different kinds of mining wastelands were studied. Also, the effects of different revegetation allocation models was valuated comprehensively by the method of grey relational analysis(GRA) to filter out the optimization models for popularization and application on different kinds of mining wastelands. The results can provide scientifical basis for the revegetaion and the formulation of relevant restoration measures on the mining wastelands in Fujian. The main results were as follows.(1)The study was carried out to grasp the changes of different revegetation ages on the wasteland of gold-copper mine of Zijin-Mountain. The results showed that: At the early stage of revegetation, the community coverage varied significantly, and reached 93% after 5-years'revegetaion. The species diversity of the herb layer and the community biomass showed an increasing trend. The content of soil water-stable aggregates(>0.25 mm) reached 62.27% after 5-years'revegetaion, and the soil corrosion resistance was as good as the control's. The results also showed that mining took great influence on the content of nutrient and heavy metal in soil. At the first two years of revegetaion, the soil nutrient content has no significant change, and it increased significantly when the wasteland has been revegetated 5 years, but the content of available P was just 3.88 mg·kg-1. The total content of Cu, Pb, Zn, Cd, Cr and Ni showed different degrees of increasing trend, while the total content of Mn showed a decreased trend, but all of the changes were not significant. Specially, the total content of Cd was 2.53 times of theⅢlevel of GB15618-1995. The soil erosion amount reached the maximum(48.4 m3·hm-2) after 1-year'revegetation, and decreased as the time increased. (2)The results of the studying on the revegetation effect of different allocation models on the wasteland of gold-copper mine of Zijin-Mountain indicated that: At the early stage of revegetation, all of the models'community coverage was more than 85% except model A, the broad-leaf trees can more improve the herb's growth than the coniferous trees. Overall, the differences among the herb layer's species diversity among all the models were not significant, and the local flood turf can improve the species diversity of herb layer significantly. The maximum of the community biomass was 94.83 t·hm-2 and the minimum was 3.27 t·hm-2. Planting masson pine can efficiently improve the community biomass. The soil destruction rates of model B and model F were respectively 12.68% and 17.45%, this indicated that their soil corrosion resistances were good enough. The model D's soil had high nutrient content while the model B's soil nutrient content was low. The total content of heavy metal in soil among different models had certain differences. The soil erosion caused by model A was the most severe. The comprehensive valuation result used the method of GRA was model C> model D> model F> model E> model A> model B, which suggested that the revegetation effects of the models of"masson pine + local flood turf","sweet gum + local flood turf"and"masson pine + eucalypt + local flood turf"were better in the six models at the early vegetation stage on the wasteland of gold-copper mine of Zijin-Mountain, and the three models can be popularized and applied as the optimal allocation models on the mining wasteland's revegetaiton.(3)The study on the revegetation effects of different revegetation ages on coal gangue dump was carried out and the results indicated that: At the early revegetation stage, Neyraudia reynaudiana can cover the ground rapidly in a short time, and the community coverage reached 80% after 13-years'revegetation. The species diversity showed an increasing trend. All of the layers'species diversities had a certain disparity with the control after 13-years'revegetation. Specially, all the indexes of the arbor layer were less than half of the control. The sequence of the herb layer's biomass of all the revegetaiton ages was 5-year>13-year>3--year>0-year. The contents of total N, Hydrolyzable N, available P and total K increased significantly, but the content of available P was just 4.95 mg·kg-1 after 13-years'revegetation. The contents of available P and organic matter were the restrict factors of the revegetation on coal gangue dump.(4)The study on the revegetation effects of different revegetation ages on the wasteland of limestone mine was carried out and the results indicated that: There was no arbor and shrub growed on the samples of all the revegetation ages. The community coverage reached 80% after 5-years'revegetation. The change of the herb layer's species diversity was not significant. Specially, the richness index was only half of the control. The herb layer's biomass of 5-years'revegetation sample was 2.1 times of that of 3-years'. The contents of Hydrolyzable N, available P and organic matter were the restrict factors of the revegetation on the wasteland of limestone mine. Planting N. reynaudiana can improve the soil nutrient content at different degrees. At the same time, the available nitrogen and phosphate need to be applied properly while revegetating.(5)The study on the revegetation effects of different revegetation ages on the wasteland of kaolin mine was carried out and the results indicated that: After 2-years'revegetation, the coverage of the arbor and herb layer restored in some degree, while the community coverage (70%) was still significant lower than the control. The species diversities of the arbor and herb layer had some recovery, but still had significant disparity with the control. The herb layer's biomass was 2.6 times of the control. The change of the soil nutrient content was not significant, and the nitrogen, phosphorus and organic matter were the restrict factors of the revegetation on the wasteland of kaolin mine.(6)The study on the revegetation effects of different revegetation ages on rare earth ore was carried out and the results indicated that: After 2-years'revegetation, the plant coverage didn't restored significantly, and the community coverage was just one-third of the control. The species diversities of the shrub and herb layer had some recovery, but still had significant disparity with the control. The nutrient indexes were low except Hydrolyzable N (187.60 mg·kg-1), total K (26.88 g·kg-1) and available K (104.09 mg·kg-1). The total N, total P, available P and organic matter were the restrict factors of the revegetation on rare earth ore the wasteland of kaolin mine. Planting"espedeza + Neyraudia reynaudiana"couldn't improve the soil nutrient content at the early revegetation stage, and the nitrogen and phosphate need to be applied properly while revegetating.
|
PDF Full Text Request