The Study On Seedling-stage Growth, Dynamic Changes Of Soil Nutrients Of Introduced Fast-growing Poplar Breeds

The experiments of survival ratios and seedlings period of 4 poplar breeds of different densities of 2a root with 1a stock seedling were evaluated in this paper, which were carried out in three experimental areas located in Daxing' Anling woodlands of Inner Mongolia. The Logistic equation was applied to model the height of seedlings, growth increments of diameter on foot each year in the 4 poplar breeds with the density of 40×50cm. Furthermore, the seedling biomass and monthly dynamic changes of soil nutrients of 3 a root with 2a stock seedling with the density of 30cm×40cm, in Chao'Er experiment sites were reviewed in this paper. From this study we get these results as follows:1. Contrastive tests on seedling stage and the establishment of growth models of introduced fast-growing poplar breedsThe results show that the differences of survival ratios were significant of different breeds, in different experimental areas and density. However, different seedling breeds and density have different influence on caliper and height of seedlings. Hence, it can confirm primarily the poplar breeds fits for the different experiment areas.The results show that the correlations of modeling are significant drawn by Logistic equation, and all the correlation coefficients are higher than 0.988.Based on the equation, annual growth of the seedlings can be divided into four periods, survival period, pre-growth period, rapid-growth period and post-growth period. The speed of annual growth represented the rhythms as "slow-quick-slow". In the three experimental areas, average height and diameter on foot in rapid-growth period are 64.2%, 68.7%, 67.6% and 59.0%, 62.2%, 58.9% to the total annual growth respectively . The characteristic of different growth period and the growth rule each year were also evaluated is this article.Furthermore, the analysis of the growth increment of seedlings was also viewed, found the most suitable breed for Chao'Er experimental area is Populus sua veolens Fisch, for A'Lihe area and Da'Yangshu area is Populus psedosimonii×nigra CV'Baicheng'.2. The dynamic change of biomass of introduced fast-growing poplar breedsThe same organ of different breeds had the significantly difference on the different stage. The ratio of dry matter in root and stem of Populus alba×berolinensis, Populus psedosimonii×nigra CV'Baicheng ,(Populus simonii×P·nigra)×(P.nigra P·simonii) and...