Effect of Seedling Density on Nitrogen and Phosphorus Utilization and Biomass Accumulation of Aleurites montana Seedlings

The effect of different planting densities on nutrient absorption, utilization and biomass accumulation of Aleurites montana seedlings was studied by one year old seedlings with five kinds of seedling densities as D1(10 cm×10 cm), D2(15 cm×15 cm), D3(20 cm×20 cm),D4(25 cm×25 cm) and D5(30 cm×30 cm)by single factor randomized block design. The results showed that there was no distinct rule in the content change of nitrogen (N), phosphorus (P) in the same organ of A. montana seedlings among the treatments, and the nutrient content was not significantly affected by the densities. Whereas the utilization rate of N and P was significantly influenced by the planting densities. The N and P absorption rates were reduced as planting density increased. N utilization rate increased along with the time, while P utilization rate increased first and then decreased later. Within the vigorous growth stage, the lower density, the higher N utilization rate was. During the initial growth stage, the greater the density, the higher P utilization rate was. However, the rule in P utilization rate was opposite at the late growth stage. Besides, as planting density increased, the dry biomass weight per seedling, dry root biomass, dry leaf biomass and dry stem biomass all reached the maximum value in September. In the whole growing season, the ratio of underground biomass and aboveground biomass decreased first and then increased later, but the ratio value was always smaller than 1. There were significant differences in the growth rate among different density treatments in the late growth stage. In summary, the D5 was the best planting density for Aleurites montana′s seedling growth under the natural conditions. Taking fertilization, photosynthesis and economic benefits into consideration, the density could be appropriately increased based on D5.