Soil Physical And Chemical Properties And Litter Nutrients Return In Different Development Stages Of Chinese Fir

Based on the analysis of the soil physical properties, soil chemical properties, litter standing crop, litter nutrient content and litter nutrients return quantity under different development stage of Chinese fir forests in the national forest farm of Fujian province, researching the change of the soil physical and chemical properties in different development stage of Chinese fir, and on the basis of correlation analysis, researching the relationship between the soil physical and chemical properties and the correlation between soil and litter macroelements content.The results show that:(1)Along with the growth of Chinese fir, the soil bulk density showed a trend of increase, the water content, the soil total porosity and soil air permeability showed a trend of decrease. In order to maintaining the water and soil conservation function, the cutting stage of Chinese fir plantation should be at least after nearly mature, namely after25years old.(2)Along with the growth of Chinese fir, the trend of the soil macroelements content is down-up. The total nitrogen, alkaline hydrolysis nitrogen and the available phosphorus content are the lowest at nearly mature forest stage, improving at mature forest stage, the total phosphorus, the total potassium and the available potassium content are not obvious along with the development of Chinese fir. In order to maintaining the soil macroelements content, the cutting stage of Chinese fir plantation should be in the later period of mature forest stage, namely after30years old.(3)Along with the growth of Chinese fir, the trend of the soil trace elements and microelements content is down-up. The manganese content increased at nearly mature stage, the total magnesium and total iron content increased at mature forest stage, the total copper and zinc content are the highest at mature stage. In order to maintaining the soil trace elements and microelement content, the cutting phase of Chinese fir plantation should be after mature forest stage, namely after35years old.(4)Along with the growth of Chinese fir, the trend of the soil pH is up-down-up, the trend of soil organic matter content is down-up, the soil organic matter content is the lowest at mature forest stage. According to the law of soil pH and organic matter content, the cutting phase of Chinese fir plantation should be after mature forest stage, namely after35years old.(5)The return quantity of litter’s total nitrogen is the most at nearly mature forest, the return quantity of litter’s total phosphorus and total potassium are the most at mature forest, the return quantity of litter’s total nitrogen total phosphorus and total potassium at over-mature forest are not much. In order to making the litter’s nutrient fully return to the soil and absorbed and utilized by Chinese fir, the cutting phase of Chinese fir plantation should be at mature forest stage, namely at25～30years old.(6) The correlation between the soil physical properties and most of the chemical properties is not big. The correlation between soil organic matter content and soil macroelements content is significant.(7)There is significantly negative correlation between the soil total nitrogen content, hydrolytic nitrogen content and the total nitrogen content in litter decomposition. The correlation between phosphorus and potassium content of soil and litter are not big.