A Study On Technology Of Producing Sedum Spp. Mat For Light Roof-Greening

As an important part of the ecological architecture, Green roof has positive effects on the environment, economy and society. To create a low-cost, low-maintenance green roof mode, we did some research on the screening of the substrates for the prefabricated Sedum mat, the producing of the Sedum mat, as well as the propagation of the Sedum plants, so as to create a suit of light roof-greening technology to popularize green roofs in Shanghai and the surrounding area.In the experiment an orthogonal experiment of 3 factors and 4 levels was adopted to screen the substrates for the Sedum polytrichoides and S. sarmentorsum mat prefabricated for the green roofs with the peat, perlite and palm fiber as the substrates materials. The results showed that, 1) S. polytrichoides had a strong root system and can go well in a 2.5cm substrate layer, so it was suitable as the plant material for green roof mats; 2) No.4 (Peat: Perlite: Palm fiber was 4:1:1) and No.7 (Peat: Perlite: Palm fiber was 6:1:2) mixed substrates out of the nine mixed substrates had a remarkable effect on the increase of the S. polytrichoides root biomass with a higher root-crown ratio; 3) The palm fiber played a positive role in connecting the substrates and the plant roots, which enhanced anti-fragile and helped the successful mat formation. Therefore, we recommend No.4 and No.7 mixed substrates for the S. polytrichoides mat prefabricated for green roofs; 4) S. sarmentorsum could not go well in the 2.5cm substrate layer with its succulent root system, which is not good for the mat formation; 5) S. sarmentorsum had low root-crown ratio for its height and weak roots, so it is not suitable as the plant material for the prefabricated mat producing. As the successful plant material for the Sedum mat producing, S. polytrichoides was dealed with by four different cutting methods: vertical and non-cut (A), horizontal and non-cut (B), vertical and cut (C), horizontal and cut (D) to study its quick propagation techniques. The result showed that, 1) The cutting treatment accelerated the growth speed of the above ground parts of S. polytrichoides, and the growth speed of the cut plants(C,D)were twice as much as the non-cut ones(A,B)in the twenty days after they were planted. 2) The cutting treatment had positive effects on the root length while negative effects on the root average diameter, both of which had achieved the very significant level; 3) The cutting treatment increased the root surface area, the quantity of the tips and forks, which effect had achieved the significant level; 4) The horizontal cutting treatment has a weak positive effect on the growth of the root and above ground parts of polytrichoides, which was not significant.