The Applied Evaluation Of Twelve Ground Covers In Beijing Area

Ground covers have an important role in maintaining the urban landscape of biodiversity,soil fertility, water conservation, improving land use rate and so on because of its adaptability,fast growth, good landscape effects and extensive management features. It plays an important role in urban landscape construction, becomes an indispensable part in city garden communities and has a great significance in protecting the beautify of our environment and improving our city’s image. After an investigation, we selected plants in Beijing area which were strong shade-endurable and extensive to management. Through field investigation, we captured plant image samples, then filtered out 12 representative images, assessed by Semantic Differential method( referred to the SD method) and analyzed the data using factor analysis.Secondly, to quantify quantitative calculation of the ecological functions of different types of garden plants as the basic unit, we tested the effect of carbon-fixing, oxygen-releasing,dust-retention, water absorption of stem and leaves, soil anti-erodibility and permeability.Finally, we estimated the establishment and maintenance costs, breeding and environmental benefits of different under-forest cover plants, selected which were fit for Beijing area to provide technical guidance and theoretical support for future use.When evaluated the landscape effect of 12 ground covers by using SD method, the results showed that Cosmos sulphureus, Pennisetum alopecuroides ‘Little Bunny’ and Calamagrostis epigejos had better landscape effect. As for ecological benefit, Zinnia elegans had better carbon-fixing, oxygen-releasing and dust-retention effect.Pratia nummularia had significant water absorption, soil anti-erodibility and soil infiltration effect. Cosmos sulphureus and Leymus secalinus had better carbon-fixing and oxygen-releasing effect. Pennisetum alopecuroides‘Little Bunny’ had better dust-retention and soil infiltration effect. Carex leucochlora and Carex lanceolata had better carbon-fixing and soil anti-erodibility effect. All the ground covers had the effect of deceasing soil bulk density.In terms of economic efficiency,planting Miscanthus sinensis ’Variegatus’ had the highest benefit, reaching more than 1.8million yuan per hectare. The economic benefit of Pratia nummularia, Carex leucochlora and Carex lanceolata reached more than 1 million yuan per hectare. Standard vary with diffenent forest, soil and environmental conditions when selecting under-forest cover plants. We need to combine the actual situation and make scientific selection.From what has been discussed above, Cosmos sulphureus,Pennisetum alopecuroides‘Little Bunny’ have better landscape and ecological effect, Pratia nummularia and Miscanthus sinensis ’Variegatus’,Carex leucochlora and Carex lanceolatahave better ecological and economic effect, which are the better species for under-forest use and suitable for application and popularization in Beijing area.