Soil Seed Bank And Enzyme Activity Of Different Vegetation Reconstructed Types In Open-pit Mine Dump

This study takes the soil and vegetation of Heidaigou open-pit coal mine dump platform as the research object,and takes the natural recovery grass of the dump platform as the control,using the method of combing field investigation indoor analysis,The change characteristics of aboveground vegetation community,soil seed bank and soil enzyme activity in six types of vegetation reconstruction(Caragana korshinskii,Sabina vulgaris and Prunus armeniaca shrubwood,and Stipa capillata+Medicago sativa,Stipa capillata+Achnatherum splendens,and Medicago sativa grassland)were studied.Comparing and analyzing the relationship between ground vegetation and soil seed bank,as well as the correlation between soil characteristics,in order to provide the basis for the reclamation benefit evaluation and species selection of this dump.The main research results were as follows:(1)The soil seed bank of six types of vegetation reconstruction germinated thirteen kinds of plant seeds in total,belonging to four families and ten genera,among which,the seeds of Gramineae plants were as high as six species,followed by Compositae.The species life type of soil seed bank was mainly perennial and annual herbs.There was a trend of Stipa capillata+Medicago sativa>Stipa capillata+Achnatherum splendes>Sabina vulgaris>Medicago sativa>CK>Caragana korshinskii>Prunus armeniaca in the density of soil seed bank in various types.The plant seeds in the soil were mostly concentrated in the depth of the 0-10cm soil layer,and the soil seed density in this layer accounts for 98.22%of the total density of the seed bank;and with the increase of the soil depth,the number of soil seeds shows a sharp decline.(2)There was a close relationship between the ground vegetation and the soil seed bank.The density of soil seed bank was higher than that of vegetation density in different vegetation reconstruction types,among which the density of soil seed bank in the Stipa capillata+Medicago sativa sample was much higher than that of the ground vegetation density,9.81 times higher than that of the ground vegetation density.There were twenty-two species of ground plants in the field survey,fourteen species of germination plants were recorded in soil seed bank,there were eleven species of common species,the similarity of which was 1.5714.The life types of vegetation species in various types of samples were mainly annual and perennial herbs.(3)The improvement effect of shrub sample type on soil physical properties of dump in this mining area was better than that of herbal sample,and it was better than that of natural recovery grass,among the six species of vegetation reconstruction,Sabina vulgaris shrub and Stipa capillata+Medicago sativa herbal samples have better improvement effect on soil physical properties of dump platform.(4)The changes of soil sucrase enzyme,cellulase and amylase activity in different soil depth of six kinds of vegetation reconstruction types showed ground aggregation,in addition,the activity characteristics of three kinds of soil enzymes within the depth of 0-10cm soil layer showed the change rule of activity of soil sucrase>amylase>cellulose;and there was a significant positive correlation between soil sucrase,cellulase and amylase activity(P<0.01).(5)There was negative correlation between soil bulk density and soil enzyme activity and soil seed bank index;while soil porosity and water content were positively correlated with it;soil enzyme activity was positively correlated with soil seed bank density and species diversity(P<0.05).(6)Based on the comprehensive analysis of soil seed bank,soil physical properties and soil enzyme activity characteristics of different vegetation types,it was suggested that the two types of Prunus armeniaca and Stipa capillata+Medicago sativa should be preferred in vegetation reconstruction of the dump.