Seedling Nutrient Characteristic And Effect Of Nitrogen Source And NPK Mixed Fertilizers On Populus Tomentosa

Populus tomentosa is one of the dominant tree species developed quickly in recent years in China.It is important to study the seedling nutrient characteristic of Populus tomentosa in order to improve the seedling nutrient management. This paper studied the absorption, distribution and utilization of different nitrogen forms at the same N application level of clone 83 of Populus tomentosa seedlings by using the technique of stable isotope 15N trace as materials. The differences of nutrients'content in the root, stem, leaf of three clones of Populus tomentosa were analyzed and the seasonal variation regulation of seedling height and ground diameter was discussed. Regression analysis was also applied to study the correlativity between biomass and N, P, K content in leaf. The results showed that the effects of N, P, K mixed fertilization on the growth of Populus tomentosa seedling were significant. According to statistcs analysis, we selected the optimal N, P, K ratio and rate, which provided scientific and rational fertilization basis for Populus tomentosa.The main results were:(1)The content of plant total nitrogen and the labeled nitrogen fertilizer had the same pattern, although the treatments was different. After one week later the content of plant total nitrogen and the labeled nitrogen fertilizer was remarkably increasing, both of them reached the peak after 28 days of fertilization.(2)The differences of N, K, Ca, Fe, Zn elements content in root of three clones of Populus tomentosa were extremely significant,and the difference of P content in root was significant.(3)The differences of K, Ca, Mg, Fe, Zn content in root of three clones of Populus tomentosa were extremely significant, and the difference of N content in root was significant.(4)The differences of N, Ca, Fe, Mn, Zn elements content in root of three clones of Populus tomentosa were extremely significant,and the difference of K, Mg, Cu content in root was significant.(5)The seedling height and ground diameter of three clones of Populus tomentosa steadily growed from June to September and growed slowly or stopped after September. According to the growth of seedling and ground diameter, clone 50 was the optimal variety, and the growth of clones 83 and 30 was similar.(6)The quadratic curves can preferably describe the relation between seedling biomass and N, P, K content in leaf.(7)The fertilization experiment showed that the seedling growth of triploid Populus tomentosa was significantly promoted by fertilization treatment. When the amount of N, P, K fertilizer was 4g/tree,6g/tree,6g/tree, respectively, the growth of seedling height and ground diameter all reached maximum. According to the biomass in different fertilization treatments, the seedling biomass reached maximum with N, P2O5 and K2O application of 12g/tree, 6g/tree, 6g/tree, respectively.