| The research hot spot of ecological environment protection are the comprehensive utilization of lake sludge and the ecological restoration of mine.Taking daye lake sludge as the research object,to screen out the plants with strong adaptability to the sediment.Through the study of Photinia fraseri,Camellia sasanqua,Ligustrum vicaryi,Rhododendron,Euonymus japonica,Euonymus japonica cv.Aureo-ma,Quercus acrodon,Gardenia jasminoides and Reineckia carnea with strong adaptability to the sediment,and screen out the plant type which was most suitable for the growth of the sediment,to lay the foundation for the mine reclamation.The main conclusions are as follows:(1)Through the analysis of the nutrient content and heavy metal content of dredged sediment in Daye Lake,it is found that the nutrient content of the sediment is rich,and the total potassium content is up to 44.84g/kg,which belongs to a very abundant level.The contents of organic matter and alkali nitrogen are 30.81g/kg,122.16mg/kg,belong to the second level,the total nitrogen,total phosphorus,available phosphorus and available potassium belong to the third level;Total mercury,total lead and total zinc are reached the national standard(GB 4284-84)about content of the dredged sediment;Total copper,total arsenic and total cadmium content are higher than the national sludge agricultural standards,reached the sludge agricultural standard limit of 2.73 times,2.23 times and 2.28 times.(2)By analyzing the relative growth rates of nine plants,it was found that the death of Rhododendron and Quercus acrodon showed that the two plants were less adaptable to the sediment and were not suitable for growth in the sediment.The other seven kinds of plants had different growth,among them,Photinia fraseri,Euonymus japonica and Reineckia carnea grow well,and the growth rate of these three plants was 0.0078g/g·week,0.0226g/g·week,0.0505g/g·week,indicating that these three plants are highly adaptable to lake dredged sediment.(3)By analyzing the enrichment ability of heavy metals in nine plants and the change of heavy metal content in the sediments,it was found that the nine plants did not have the ability to reduce Hg and Pb in the sediment,but had different degrees of reducing effect to the other four kinds of heavy metals Cu,Zn,Cd and As.Among them,Euonymus japonica had the strongest ability to reduce the heavy metal Cu and heavy metal Zn in the sediment,and the ability of Photinia fraseri to reduce the heavy metal Cd in the sediment.Ligustrum vicaryi and Reineckia carnea had stronger ability to reduce As in the sediment.(4)Through the analysis of the nutrient content of the dredged sediment,the results showed that the nutrient contents of different plants had different degrees of improvement.Photinia fraseri had the ability to increase the contents of total nitrogen,total phosphorus,total calcium and total magnesium in the sediment.Camellia sasanqua had the ability to increase the contents of total nitrogen,available potassium,total calcium and total magnesium in the sediment.Rhododendron had the ability to increase the contents of available potassium and total magnesium in the sediment.Euonymus japonica cv.Aureo-ma had the ability to increase the contents of available potassium,total calcium and total magnesium in the sediment.Quercus acrodon had the ability to increase the contents of available potassium and total magnesium in the sediment.Reineckia carnea had the ability to increase the contents of total calcium and total magnesium in the sediment.Ligustrum vicaryi,Euonymus japonica and Gardenia jasminoides had the ability to increase the contents of total magnesium in the sediment.(5)To sum up,the growth status of nine kinds of plants was taken as the main evaluation index.With reference to the enrichment ability of heavy metals and the change of heavy metal content and nutrient content of nine kinds of plants,the plants which most suitable for the growth of the sediment are: Photinia fraseri,Euonymus japonica and Reineckia carnea. |
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