Vertical Distribution Characters Of Organic Carbon,Nitrogen And Phosphorus In Soil-Chinese Pine Forest Ecosystem Developed From Limestone And Granite Parent Materials

To study the relationship between soil organic carbon developed from different parent materials and nitrogen fixation in mountain area ecosystem is of great concern. To explore effects of soil chemical properties developed from different parent materials to reasonable planting, forest ecosystem protection, soil quality improvement have practical significance. It is also important to study CaCO3content in soil and its influence on improving soil quality and spatial distribution of soil nutrients. Three sample plots were chosen in both the limestone and granite parent materials developed soils under Chinese pine forest in Song Mountain Nature Reserve. Five soil profiles were chosen from each plot and soil samples were taken from different layers within1m soil depth. Quarter method was used. The results showed:(1) Influences of two soils developed from different parent materials to the vertical distribution of soil organic carbon, total nitrogen, available phosphorus and available potassium are with the same trend, their contents were highest in the upper layer, and declined with increasing soil depth.(2) There were no significant differences in surface (0cm-20cm) nutrient contents between soils developed from two kinds of parent material, while significant differences in nutrient contents from20cm to100cm, with limestone parent material higher than granite parent material.(3) CaCO3can not be found in soil developed from granite parent material, while great amount of primary CaCO3were found in soil developed from limestone parent material, soil CaCO3content increased with increasing soil depth.(4) Correlation analysis showed:extremely significant positive relevance were found between soil organic carbon content and total nitrogen content in both limestone and granite developed soils, negative relevance were found between soil organic carbon content and C/N, total nitrogen and C/N in limestone developed soil, low positive relevance were found between soil organic carbon content and C/N, total nitrogen and C/N in granite developed soil. Relevance between soil organic carbon content, available phosphorus and available potassium were extremely significant and positive in limestone developed soil, while relevance between soil organic carbon, available phosphorus and available potassium were significant and positive in granite developed soil.(5) The space variation law of two soils developed from different parent materials showed, contents of nitrogen, phosphorus and potassium in both Chinese pine leaf, surface litter and upper soil layer were with the same trend, they declined dramatically with increasing soil depth, and significant differences were found; Nutrient contents in limestone parent material soil were higher than those in granite parent material soil, while differences were not significant.