Studies On The Optimization Of Botanical Allocation Patterns For Water-Saving Green Space In Beijing

the measurenemt of the water-saving characteristics of different plants are made on the standard plots in different green land. The differences of allocation pattern of green land in different function districts, structure of plants, species abundance and diversity, irrigation patterns, water consumption per unit area as well as the capital outlay were conducted and evaluated. The data shows that the allocation patterns of green land in Beijing are mostly arbor-shrub-herb in different layers. The green land allocation patterns in campus are much better, and the patterns along the city roads are the worst in all these patterns. Sprinkler irrigation is used in campus green land, this will save 0.05m~3 water per square meter each year than other green land. Based on this investigation, Acer truncatum, Lonicera maackii, Poa pratensis were chosen as representative plants in higher, middle, and lower layer respectively, their water consumption of transpiration in different crown densities, the result are following: From April to June, when the crown density is 0.5, water consumption of is 37.4mm and 7mm lower respectively than that their crown density is 0.3, and plant growth are the same. From that, in order to save water, we can safely say that the best allocation pattern is arbor, shrub, and herb under a proportion of 10:11:17. So we have established an overall assessment system suitable for plant allocation in Beijing. It consists of four type indicators: ecological characteristics indicators, water-saving characteristics indicators, landscape characteristics indicators and economic characteristic indicators. These four type indicators are splited into some smaller, applicable indicators respectively. Moreover, an integrated assessment model based on fuzzy sets is used in evaluating and ranking the green land plant allocation patterns in different function districts. With that, further optimization in plant allocation pattern in campus was conducted. Finally, we bring forward three constructive water-saving plant allocation patterns.