Comparison Of C, N, P Content And Nutrient Resorption Efficiency In Branch And Leaf Of The Four Economic Forest

The definition of soil nutrient is the necessary nutrient elements provided for plant growth by soil, which can be absorbed directly or absorbed after transformation. The content of soil nutrient has direct influence on plant nutrient, growth and development. The content of soil nutrient and plant nutrient are affected by their own physicochemical property, hereditary capacity, climate, environment and other aspects. The nutrient of the branches and leaves mostly comes from the soil with some from the nutrient backflow of the aging organs. It makes the nutrient stay longer in the plant that the remigration or secondary distribution of the nutrient from aging branches and leaves or other organs to provide most of the nutrient for the new organs. This process is nutrient inner absorption. The nutrient inner absorption is an important nutrient provision for plant growth. The nutrient resorption efficiency is the percentage of the nutrient content migrated in the aging process to the nutrient content before aging. The related studies on the circulation of nutrient elements and nutrient use efficiency are very important and more scholar pay attention to them. The fertilizing amount, production and management of the plants can be analyzed by the measurements on SPAD of the leaves, which can know about the SPAD or the green degree of the leaves quickly.Different altitudes have different soil moisture content, which results in different soil physical chemistry property, soil nutrient elements, affecting the growth and ecological physiological property. Different management level indicates the different degree of human management, fertilizing, plough, weeding. Different season indicates different solar radiation, rainfall, exposure, climates. All these things will affect the growth of the plants and make them different. The nutrient absorption of the branches and leaves from the soil will be affected by the change of the altitude, management level and the alteration of seasons, which make the nutrient content vary with the alteration of the altitude and seasons.With the four economic forests, including Phyllostachys pubescens, Castanea henryi, Camellia oleifera , Vernicia fordii, as research objects, analysing the change of the content of SPAD, carbon, nitrogen, phosphorus of plants and soil. There are some analyses of SPAD, carbon, nitrogen, phosphorus'variance analysis in the altitude, management level, season and difference comparison in the species, nutrient content, nutrient resorption efficiency, while the correlation among elements. The influence between the mutative factor and the nutrient content in the four economic forests are discussed, in order to reveal the variational laws of carbon, nitrogen, phosphorus content and nutrient resorption efficiency in branch and leaf of the four economic forests.The main results follow as:The SPAD of the camellia oleiferas'leaves is the highest in four economic forests. Different altitude, management level and season have different SPAD. There is a significant correlation between the SPAD and the management level and season. The main factors of the change of the SPAD are solar radiation and season.The carbon content of the aging branches and mature branches are higher than that of the leaves, while the nitrogen content of the leaves is higher than the live branches which is higher than that of the deadwood. So does phosphorus content. The nitrogen content of the leaves is highest, while the phosphorus content of the branches is the lowest. The carbon content of the evergreen forest like Phyllostachys pubescens and camellia oleiferas are higher than that of the deciduous forest like Castanea henryi and Vernicia fordii, while the nitrogen content and the phosphorus content are the opposite. The plant nutrient content varies with the season obviously, having a significant correlation with the season. Some elements have significant relation with altitude and management level.The soil carbon content of the evergreen forest is higher than that of the deciduous forest. The total nitrogen content of different trees decrease as follows: broad-leaved forest> bamboo forest>shrub. The carbon content, nitrogen content and phosphorus content all have notable relation with seasons. The soil nitrogen content is significant related to altitude.The nutrient resorption in carbon, nitrogen, phosphorus of the four economic forest branches, leaves and soil as follows: carbon>nitrogen>phosphorus. The nitrogen resorption of the branches and leaves is highest, while the carbon, phosphorus resorption of the soils is the highest. Nutrient resorption efficiency of the three elements in the four economic forests has positive and negative number. The phosphorus resorption efficiency is highest, while the carbon, resorption efficiency is the lowest. The nitrogen, phosphorus resorption efficiency of the deciduous forest are higher than that of the evergreen forest.There is a significant correlation between the altitude and season of the phosphorus resorption efficiency in the economic forest. So does carbon and nitrogen nutrient resorption efficiency. The plants'nutrient resorption efficiency in the management level has a significant correlation between the management level and season. The nutrient resorption efficiency all have notable relation with seasons, which are commonly related to altitude.Among the elements has not a remarkable correlation, which is notability in soils. The correlative analysis between plants and soil in the management level and altitude is partial relativity. There is a significant correlation between plants and soil'elements on the basis of the shortage supply in soil nutrient. With speices as a unit, not plotting the management level and altitude, has a significant correlation between plants and soil'nutrient elements. The correlation between nutrient resorption efficiency and soil'elements are not significant. Key words: Economic forest; Branches and leaves; Carbon, nitrogen, phosphorus; Nutrient...