Research On Root Distribution And Drought Resistance Of Young Chinese Pine Forests In The Dry Mountain Area

The survival and preserve rate of the afforestation are affected by bad site conditions in dry mountain area. Solving the problem of drought is an important part in forestry scientific research. The simple and effective measures to fight the drought is very important in production and science. In this study, we research the distribution of young Chinese pine forests in the dry mountain area,analysis the effect of fertilization, water bag, weeding and coverage on the growth of plants and water content of soil. The main results are as follows:(1) The distribution about root system of young Chinese pine forests in different ages:With age increasing of the young Chinese pine forests, the taproots grow significantly, the roots gradually become thicker, vertical distribution of root is deeper, the range change of horizontal distribution is not obvious, the root biomass increase significantly and begin to underlay. In vertical direction, the average root diameter decreases with the increase of soil depth and the root biomass shows a variation trend of inverted V, namely increasing firstly and then decreasing.(2) Effect of different measures on the growth of young Chinese pine forests:All different fertilizer treatments can promote the growth of young Chinese pine forests. Nitrogen and potash can obviously promote the seedling growth, but phosphate fertilizer is relatively weaker. Mixed fertilizer is better in the growth of trees than single fertilization. Different watering treatment can also promote the height and diameter growth of Chinese pine forests.Watering more is benefit in growth and the same amount of water poured in several times is better than in one time. Completely weeding is not conducive to the growth of seedlings. After covering the young forest, the height, diameter and shoot of young Chinese pine forests grew more significantly and the growth was improved greatly compared with the control group.(3) Responses of soil moisture in different measures:Soil moisture of fertilization treatments is lower compared to the control group, and the soil moisture decrease with the increase of fertilizer rate. The influence of different fertilizer proportion to soil moisture has no obvious regularity. The mount and times of watering can both improve soil moisture. The surface soil moisture reduced significantly after weeding, while the influence to lower soil moisture is weaker. Coverage can increase the soil moisture, especially the surface soil moisture increases significantly.(4) The influences of four different measures to growth and soil moisture of young Chinese pine forests are as follows:The completely weeding is not conducive to the growth of young Chinese pine forest and will lose soil moisture; Fertilization can increase the growth of Chinese pine forest, but it will reduce the soil moisture; Watering is the most direct measure for water filling and drought relief, and coverage is also good for drought relief.They both can improve the growth and soil moisture of Chinese pine. Because of the water shortage, watering difficultly and the larger cost, membrane and the straw are the effective means to solve the water shortage in drought mountain...