Study On Cultivation Techniques And Papermaking Characteristics Of New Clones Of Populus Tomentosa

The cultivation techniques and papermaking Characteristics of three new clones of Populus tomentosa (BT17, BL193, BL175) were studied in this paper. The tested traits include phenological phases, seedlings fertilizer scheme of N, P, K, density effects on seedling's yield and growth, the relations between siliviculture density and growth. The physiological and papermaking characteristics of the three new clones were also studied in order to guide oriented cultivation of new clones of Populus tomentosa.Result showed that there are only a little difference among the phenological phases of the three clones. Their phenological phases could be divided into the ex- period and em-period. Seeing from the Variation coefficient, the biggest d-ifference lies in the period of the expend of sprouts in the ex-period, while in the em-period ,it lies in the beginning time of defoliation .These two periods could be used as the evidences to judge the rapid growing stage of clones. The growth regulation both the length of seedling height and collar diameter turn to be "S" curve. According to logistic model, the growth periods of seedlings can be divide into 4 stages: the period of survives, the early period of growth, the fast growing period and the late growth period.The influences of fertilization are different on one-year-cuttage seedling's growth index and physiological index. The growth index are sensitive to fertilization; phsiological index,such as cor certration of pigment, nitrate reductase activity, photosynthesis and transpiration are sensitive to fertilization while the chl a/b, the stomatal conductance and other data of physiology are not. The suitable time of fertilization should be in the fast growing period. N played an impotant role in the fast growing period , following P or K. For the growth period of Populus tomentosa is a litte longer, the suitable fertilizer shoud be given to it in the em-period in order to speed up the growth ofseedlings and it' s woodiness.The results of different density experiment showed that density influence-ed either the height of seedlings or the coller diameter of seedlings. Generally, the height of seedlings and coller diameter will increase respectively as the density decreases and then falls down, for the density is too small and the soil turns to be bare and is not good for the growth of seedlings. In the experiment, the fast growing period of coller diameter grows earlier than the height. The study showed that the growth of height in the fast growing period takes larger percentage in the whole growth period than coller diameter.The new clones has the obvious rapid growth speed. It' s biggest growth period is usually at the third or fourth year in the spacing of 1m X 2m, so it can definitely be used as short rotation tree (4 years) .The condition of soil greatly influences the growth of the clones. It will grow better and faster when the soil has good fertilization, ventilation, neutral pH or little alkaline condition, while under other condition if s growth will be dallied. Among these three clones, BT17 had biggest growth in sandy and moist soil, The BL175 ' s growth was bigger than the others in viscidity and conglomerate black soil, while BL193 had good ability to suit poor and loam sandy soil.The silivicultrual spacing had little influence on the height of the three new clones except the great spacings. The DBH, volume, crown breadth and the growth of shoots increase obviously as the density decreases.The Photosynthesis rate of these three clones are similar to each other, but the time the largest photosynthesis rate reached will get shorter under little density.The water parameter of Ψssat . Ψwtip, RWCtip, ROWCtip, Va/Vo, εmax shows that the three clones have the similar philology of resistance to drought. To see overall, the BL193 has greater resistance than BT17, BL175.The silivicutrual spacing also influenced the fiber length of BT17, but its effect was not significent. The fiber length decreases from the disc at the bottom to the top, which shows that the...