Effects Of Different Hole Planting Density And Different Coverage On Platycladus Orientalis In The Loess Plateau Area

Platycladus orientalis(Platycladus orientalis (L.) Franco) is specific trees type in China and widely used in the Loess Plateau area, also one of the excellent species that used in landscaping, timber forest and afforestation. This study is based on Platycladus orientalis Seedlings experiment matetial and Loess Plateau of the natural environment, and engaged in the7kinds of hole planting density. This study discussed the density differences, relationship among Platycladus orientalis seedlings and rate of survival. The study also carried out another6different covering methods, further disscussed growth differences and rate of survival of seedling height and diameter study of Platycladus orientalis Seedlings under different covering methods. It comprehensive evaluates the effects of different treatments on growth of Platycladus orientalis Seedlings, and provides the theoretical basis and technical support for Platycladus orientalis seedlings cultivation in the Loess Plateau area. The conclusions are as follows:1In Shanxi Pingshun County, the growth period of Platycladus orientalis Seedlings is from mid of April to mid of October. The rapid growth period is from June to August, about80%of the annual tree height and diameter growth of the concentration in this3months.2The growth of Platycladus orientalis Seedlings have a lower requirement of planting density, planting density is in the9lines/holt which can survive, and suitable growth density is1lines/holt-2lines/holt. High or low seedlings density will lead to cost-increasing and gree benifit-reducing of Platvcladus oriental.3Platycladus orientalis seedling height increment and hole planting density have a significant negative relationship, the relative coefficient is up to-0.86121*; the growth of ground diameter also negatively related to hole planting density, the coefficient is up to-0.8550*. All these data illustrate that the planting density of Platycladus orientalis, to a certain extent, will affect the tree height and diameter growth.4Under the natural environment of the Loess Plateau area, height growth and soil moisture content of Platycladus orientalis seedling showed a significant positive relationship, the relative coefficient is up to0.87536*, the relative coefficient of ground diameter growth and soil moisture content is up to0.76758. It shows that soil moisture content and diameter growth of Platycladus orientalis are closely related, significantly affecting the tree height and diameter growth.5In the Loess Plateau area, water-permeability plastic film mulching, gravel, plastic film mulching eco-mat, in different degrees, has played a role in soil-water conservation and soil heat preservation, in which the best moisturizing effect of water-permeability is plastic film mulching. heat preservation effect of plastic film mulching is best. And suitable covering method of diameter growth of Platycladus orientalis is water-permeability plastic film mulching, followed by gravel coverage. If we consider the economy, simple type, environmental protection, healthy and other factors, suitable coverting method in some other areas is gravel coverage.