Studies On Key Techniques Of Nitrogen Top Dressing For Larix Olgensis Henry Seedlings

Larix olgensis Henry is one of the most important rapid growth and high yield timber species in northeast China. Nitrogen is one of the key nutrient for Larix olgensis seedling growth and hence the supply of nitrogen in each growth stage is very important. This paper systematically studied Larix olgensis seedling fertilization technique, including urea fertilization requirement, top dressing time, top dressing proportion and the methods of the fertigation. The height of seedling, caliper, biomass and nitrogen distributions of root, stem and leaf were studied through Larix olgensis seedling. The main results are as follows:1) The influences of different amount of nitrogen top dressing on the seedling height, caliper, biomass and the content of N in plants was significant. The optimum amount of fertilization is 120kg·ha-1; 2) The suitable time of top dressing for transplant seedling (1-1) i early July and the suitable last time fertilization for 1-0 seedling is in Mid-august; 3), The best top dressing proportion is 1:2:2 for 1-0 seeding seedlings.4), Broadcast application suits Larix olgensis seedling.