| The ecological restoration of wasteland in mining area has caught an extensive attention of the world.Lots of unmanaged wastelands in mining area are enormous hazards to cause environment pollution,soil erosion and land desertification,which threaten to human survival severely.Panji District,which is a region of heavy industry focused on un-renewable energy such as coal,electric power and chemistry,is located in Huainan of An’hui Province.While the coal industry makes great contribution to Panji economy and social development,a large area of land subsidence and wastelands are caused by intemperate over-exploitation,which deteriorates the ecology and environment of mining area day by day and impacts on the normal agricultural production,regional economic production and improvement on people’s living level. Strengthening the restoration of destroyed ecological system in wasted mining area has become a key research subject of ecology.Based on the ecologic recovery theoretically,this paper discusses the vegetation restoration mode and its effects in mining area of Panji in Huainan by on-site investigation and monitoring combing the relevant index determination.The main research contents include the following five aspects:①vegetation features of mining area in Panji,Huainan;②research on the vegetation restoration mode of mining area in Panji,Huainan;③effects during the soil restoration of mining area in Panji,Huainan;@Optimization of vegetation restoration mode in mining area in Panji,Huainan.The main research conclusions are as follows:Ⅰ、Vegetation Features of Mining Area in Panji,Huainan(1) There’re37families,79genus and97species of seed plants in mining area of Panji,Huainan,which account for22.70%,8.80%and3.88%of the family,genus and species of An’hui plant amount.This means the mining area of Panji,Huainan is a region lack of biological diversity.The composition dominance is very clear in the seed plants of this area.lt focuses on single species.Leguminosae,Gramineae,Compositae,Rosaceae, Euphorbiaceae and Salicaceae are the dominant families.There’re40genus and50species in those6families,which account for50.63%and51.55%of the genus and species amount for regional seed plants.The single-species is the major composition of seed-plant genus in this area,including Artemisia, Polygonum and Populus as the dominant genus.There’re12 distributions and5variations of geological elements for genus.The subtropical element accounts for61.19%of the genus amount in this region,which dominates obviously.This means the genus feature focuses on subtropical element with the feature of transiting to tropical one.The97species of seed plants in this region can be divided into12distributions and5variations.The tropical element and subtropical element account for32.55and66.25%of the species amount respectively.The further weakening of tropical element reflects the integration and combination of tropical element with subtropical element of the seed-plant genus in this region,featuring the northern subtropical distribution.(2)During natural succession,the Leguminosae and Rosaceae were dominant species in this region.Leguminosae and Rosaceae should be taken as the main species in vegetation restoration.The distribution law of vegetation geological element in this region is it’s easy for plants of tropical distribution to inhabit in mining area rapidly.There’s good nature of pioneer plant.However,the proportion of tropical nature in areas of family,genus and species decreases gradually while the subtropical nature increases correspondently.(3)The classic sampling plot is applied for statistic and analysis on the succession of original plants in different restoration stages in mining area of Panji,Huainan.The result indicates that the species increase gradually as the year of natural and original succession grows.Meanwhile,the community layer tends to be more complicated,transiting from2-layer shrub-herb to3-layer arbor-shrub-grass.The diversity index of species also increases slowly.(4) The natural succession of vegetation restoration level in mining area of Panji,Huainan is still in a low stage,so the artificial succession is still a valid path to improve the ecological environment in mining area.Most of plants in natural succession in mining area of Panji,Huainan are pioneer plants.Thus,the vegetation restoration law of natural succession should be referred.Pioneer plants and native plants should be chosen mostly for vegetation restoration in mining area.Multilayer structure is suitable for community layer.A rich restoration type with diverse species can be established only if the plant species,planting quantity and structure are colorful.Ⅱ、Research on the Vegetation Restoration Mode of Mining Area in Panji, Huainan(1) There’re problems of species shortage,easy structure and simple layer. Instructed by fundamental ecology,landscape ecology and theory of restoration ecology,this paper expects to select a ecological mode of vegetation restoration suitable for mining area in Panji,Huainan by applying the theories into every restoration mode. (2) Based on a detailed research on species composition,community appearance, species significant value,species diversity,species richness,frequency and evenness of vegetation in mining area of Panji,Huainan,this paper designs5modes of vegetation restoration in mining area:plant community mode focused on disaster prevention (MS1),plant community mode focused on nitrogen fixation and poor soil tolerance (MS2),plant community mode focused on d ecological agroforestry (MS3),plant community mode focused on science popularization and health care (MS4),plant community mode focused on landscape ecology and aestheticism of mining area (MS5).(3) Regarding community composition,structure and function as the index system,this paper completes5modes of vegetation restoration in mining area,elaborates the design points of5restoration modes and establishes kinds of restoration modes by combining the cases.Ⅲ、Effects during the Soil Restoration of Mining Area in Panji,Huainan(1)It’s not effective to restore vegetation on wasteland naturally in mining area. This can be seen in the area of physical property.The average bulk density is1.12～1.28g/cm3while the soil total porosity is low without distinguished difference,which is45.73～48.23.the capillary porosity and non-capillary porosity tend to have a similar variation with total porosity.In terms of water content law,the water content in topsoil is obviously higher than the one in bottom soil.It’s a descending law,which is0～201ayers>20～401ayers>40～601ayers.(2) In terms of chemical feature,there’s high similarity of soil chemical indexes on wasteland in mining area.Meanwhile,they’re on a low level.The organic matter content is very low,0-60cm which is only0.76%～1.52%;content of total N is0.320.85g/kg;content of total P is0.21～0.55g/kg;content of total K is0.93～1.06g/kg;content of available N is16.75～24.54mg/kg;content of available P is7.11～10.27mg/kg and content of available K is66.26～81.34mg/kg.The variation range of pH value is7.74～8.54.The soil nutrition elements are in a severe shortage state.It can be seen from shortage of P and K elements.No matter the total P or available P;no matter the total K or available K stays in a very low level. Meanwhile,the nitrogen fertilizer is also in a shortage state,which should be complemented during the vegetation restoration.(3) In terms of biochemical feature,the content of key enzyme and dehydrogenase participating into0-60cm nitrogen cycling is0.8658～3.3868μL/L.The microorganism is the main origin for soil dehydrogenase.Thus,it indicates the number of soil microorganism in wasteland before the vegetation restoration is very small.As a hydrolases existing extensively in the soil,urease is the sole enzyme which has a major impact on the urea conversion.0～60cm Its content is0.0721～0.0935mg/100g,which indicates the soil fertility and organic matter content in wasteland are in an unfavorable state.0～60cm The Catalase content is0.7533～0.8246mL/g.Catalase is a key oxidoreductases,which is generated due to the oxidation of creature breath and biochemistry of organic matter.It’s a poison for soil and creature.Thus,the poison resistance of soil in wasteland still needs to be improved.(4) All vegetation restoration in different modes can improve the soil physical property.The vegetation restoration can decrease the soil bulk density,increase soil total porosity,capillary porosity and non-capillary porosity and improve the soil water content obviously.In terms of restoration effect,plant community mode focused on nitrogen fixation and poor soil tolerance (MS2)>plant community mode focused on disaster prevention (MS1)>plant community mode focused on landscape ecology and aestheticism of mining area (MS5)>plant community mode focused on d ecological agroforestry (MS3)>plant community mode focused on science popularization and health care (MS4).(5) All vegetation restoration in different modes can improve the soil chemical property.In terms of restoration mode,the variation trend is plant community mode focused on nitrogen fixation and poor soil tolerance (MS2)>plant community mode focused on disaster prevention (MS1)>plant community mode focused on landscape ecology and aestheticism of mining area (MS5)>plant community mode focused on d ecological agroforestry (MS3)>plant community mode focused on science popularization and health care (MS4);the most obvious effect on N improvement is plant community mode focused on nitrogen fixation and poor soil tolerance (MS2) because there’re lots of nitrogen fixing plants in this mode.Thus,a proper application of nitrogen fixing plants during the vegetation restoration in mining area is possibly a feasible technical path.(6) All vegetation restoration in different modes has an obvious impact on soil urease activity,which varies with the plant species.The most obvious effect on soil urease activity increasing is plant community mode focused on nitrogen fixation and poor soil tolerance (MS2);the second most obvious effect on soil urease activity increasing is plant community mode focused on disaster prevention (MS1).In terms of soil urease activity in season variation,the activities of Dehydrogenase and Catalase are consistent,which have obvious season variation.Dehydrogenase affects are always July>October>April>January which are summer>autumn>spring>winter in different restoration modes;while there’s a little difference in season variation in soil Catalase activity: October>July>April>January, which are autumn>summer>spring>winter.Ⅳ、Optimization of Vegetation Restoration Mode in Mining Area in Panji, Huainan(1) According to the requirements of drought resistance, poor soil tolerance and salt resistance, the species of arbor trees for proper planting in mining area are Robinia pseudoacacia, Ailanthus altissima, Arborvitae chinese, Populus simonii; the species of shrub trees are Amorpha fruticosa, Vitex negundo var. heterophylla, Lespedeza buckthorns, Rosa xanthina, Folium forsythia; vine species are Parthenocissus tricuspidata, Euonymus fortunei; herbage plants are Liriope platyphylla, Alfalfa melilotus, Coreopsis grandiflora and Erigeron canadensis.(2)10cm-soil cover,a proper improvement on the soil porosity and selecting pit as soil preparation are the most favorable measures to make the soil property better. Leguminosae and Gramineae are mainly suggested for community structure on the low layer while woody plants are mainly advised for multi-layer structure.The planting way is:to choose containerized seedlings as plant type;spring as the planting season and ABT rooting powder for grow-up.(3) The wasteland in mining area is the region with severely destroyed ecological environment.Different from the region completing the restoration by standard vegetation succession,a guarantee about restoration technology is required in terms of vegetation restoration and optimization on wasteland in mining area. Supported by practical case in research area,this paper integrates different achievements of technology improvement and mode optimization for vegetation restoration on wasteland in mining areas by discussing on the improvement technology on soil substrates,plant choice,plant figuration,planting and restoration management. |
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