Study On The Growth And Roots Regeneration Of Ginkgo After Root-cutted With The Treatment Of Fertilization In Urban Landscape

In recent years, being long with sequence of urbanization process and the higher requirement on city afforestation, big tree is recognized that it play a more and more important role on city road widening, old city area reforming, garden building and courtyard planting and even city image improving. Therefore, tree transplanting methods have developed stably, especially in big tree transplanting. Even though, there are many problems needed to overcome, such as the cost, the pruning and the surviving. In order to solving problems mentioned above, Ginkgo tree are studied. Based on root-cutted Ginkgo, different combination fertilization treatments were carried out around the root-stock for stimulating root regeneration and forming fibrous roots near root-stock. By growth measuring, leaves elements determining, the leaf chlorophyll content and photosynthesis monitoring and root regeneration ability observing, the reaction of Ginkgo to the different treatments of fertilization was systematically studied after root cutting and applied fertilizer, which it provide a foundation for reducing lateral root diameter but surviving. The main results are showed as below: (1) By analysing the growth index of Ginkgo trees through root-cutted treatment, of which the average breast-high diameter is 7.70cm, it show that to maintain maximum diameter of lateral root (shortened as MDLR) at 50cm will being reducing height growth, but improving diameter at breast high slightly; the root diameter 70cm can promote growth; 60cm is the normal diameter to accord with average diameter breast-high 7.7cm of Ginkgo, this root diameter will not influence the height and breast-high of the trees when transplanted. Compared with traditional diameter being transplanted, this diameter lessen 17cm. Fertilization can increase the high growth after cutting roots, of which to maintain maximum diameter of lateral root at 50cm will increase the high growth obviously, but is lower than the ck.It demonstrate, from dynamic analysis of N, P, K in leaves, that there was not negative influence of the different three treatment of root cutting (shorted as TRC) on Ginkgo to absorbing nutrient from soil. The experiment support that rational applying fertilizer after TRC not only increase the amount of nutrient elements accumulation in leaves, but also improved photosynthesis rate and annual increment, which was obviously better than the only TRC.At the beginning after TRC, the Ginkgo net photosynthesis rate were lower slightly or even to compare with the CK. But at the later stage of growing season, the net photosynthesis rate were all as...