Study On Nutrient Solution Formula For Eucalypt Hydroponics Cutting Orchard And Effects Of Nutrition Imbalance On Growth Of Eucalypt Seedling

The Light-medium cutting propagation of eucalypt in Southern State Tree Seed and Seedling Demonstration Base has been to the large-scale and factory period.To build and manage the eucalypt cutting orchard is a very important technology during the whole period of eucalypt cutting propagation. To design the eucalypt hydroponics cutting orchard, improve the produce cutting efficiency in certain area, improve the survival rat of cutting, solve the problem of low efficiency and productivity of field cutting orchard that is very necessary. At the same time, the seedling quality is decisively affected by the nutrition imbalance and we should do more in balanced fertilization.In this thesis, using hydroponics technology, first studied the most suitable concentration and pH value for four kinds of eucalypt clones, DH 184-1, DH201-2, Guang-9 and DH32-29, and researched the effected results by nutrient solution formula. Then researched eucalypt clones of DH184-1 and Guang-9 how to be affected by the nutrient solution formula and proportion, and analysed the pivotal quality indexes of the cutting. The eucalypt seedlings were greatly affected by N element during the period of hydroponics, researched the growth of eucalypt DH201-2 clone seedlings how to be affected by different nitrogenous proportion and different nitrogenous forms such as NO₃^-N,H₄⁺-N,NH₄HCO₃-N ,CO (NH₂)₂-N.The nutrition imbalance including lacking too much one or several kinds of mineral elements and that deeply affect the growth of eucalypt seedlings. In this thesis, researched lack or too much N,P,K, Ca, Mg and S how to affect the indexes of seedling height,seeding ground diameter,,fresh seedling weight above ground, fresh hydrophily root weight of seedling,dry seedling weight above ground, and researched the growth of eucalypt DH201-2 clone and Guang-9 colne seedlings how to be affected by lack microel elements such as Fe,Zn,Mn,Cu,Mo,B to above five indexes, and expected to guide the practice in cultivating seedling.The results show that:(1) Using hydroponics technology to design eucalypt hydroponics cutting orchard and research the effects of nutrition imblance on growth of eucalypt seedlings can be carried out, and it also can be put into practice.(2) The cutting cultivated by hydroponics is far more superior in all biological indexes including survival rate than the cutting cultivated by the field cutting orchard. They mainly different in biological amount and the lignifieation degree .Among all the treatments, the survival rate of cutting is negatively correlated with average(fresh cutting weigh/ cutting length),and positively correlated with average index of fresh hydrophily seedling root, keeping the inverse proportion of different major and middle elements in following can make the fresh hydrophily seedling root grow well, N: P: K: Ca: Mg: S= (1-2): (0.15-0.7):(0.1-0.4):(0.1-0.4) ,and NH₄⁺-N:NO₃^--N= (0.15-0.2 ): 1. which also can improve the quality and survival rate of the cutting.(3) There had significant diversity in hydroponics results among the seedlings cultivated by different nutrient solution ,if the nutrient solution had different formula and proportion,different concentration and different pH value. Among the factors of kinds of clone, kinds of nutrient solution, concentration of nutrient solution, pH value of nutrient solution, the results were firstly affected by kinds of clone, concentration of nutrition solution secondly. The results of different clones cultivated by hydroponics is DH201-2 and DH184-1 are better.than Guang-9, DH32-29 is worst. Keeping the concentration of nutrient solution about 1.0 time (the EC value from 1.0ms/cm to 1.6 ms/cm) can achieve best results, in practice can keep 0.5 times; Keeping the pH value from 5.0 to 6.0 can get good result.(4) The growth of seedling and the quality of cutting were decisively affected by nutrient solution formula and proportion, especially the formula and proportion of major and middle elements. The situation of fresh hydrophily seedling root is a very important index for the hydroponocs results.(5) In effect degree of the major element to growth of eucalypt seedling, N element is the most,-to N element, the most important is to contral the proportion of different nitrogenous forms; The seedlings were deeply affected by the nitrogenous forms and proportion, there had significant diversity in all biological indexes of different nitrogenous forms and proportion treatments, and the diversity of a majority of indexes was most significant.(6) Cultivating the eucalypt seedling by balanced nutrition can get the best results. For eucalypt clone DH201-2 seedling, lack or too much any kinds of major and middle elements may lead the biological amount of the seedling decreasing; In six kinds of major and middle elements, N,P,K,Ca,Mg and S, the seedling is most significant affected by N element, more significant affected by P and K elements, Mg and S are comparatively least. (7) The effect results of lacking minor element for eucalypt DH201-2 clone and Guang-9 clone seedlings were nearly the same, they different in affected degree of biological amount between few kinds of minor elements. Of all the treatments, balanced nutrent solution was the best, lack all kinds of minor elements was the worst. In all the treatments of lack one kind of minor element, the growth of seedling was most evidently affected by lack B element treatment. Compare with balanced nutrient solution, the nutrient solution lack B element made all kinds of biological indexes decreased 30% to 73%.