The Research On Classification Transformation Technology Of Low Yield Stands Of Camellia Oleifera

Oil-tea (Camellia oleifera) is an endemic woody edible oil tree in China which accounts for more than80percent of the cultivation area of woody oil trees, it has been more than2300years in cultivation history. At present, there are50million mu of oil-tea forest in total. However, for a long time, its yields is low, and quality poor, which restrict the sustainable development of tea-oil industry. Therefore implementing low production forest improvement is necessary to promote high and stable yield of tea-oil. There are many studies on it, but its classification and improvement methods are different. In this paper, by investigating the causes of low-yield forest, we divided low-yield forest into different types according to age and extent of excellent variety and conducted the research on technical improvemen. The main results are as follows:1,Studies on techniques for changing crown of tea-oil. Changing crown technique was been made in the tea-oil seedling stand which age was less than40years, forest form relatively tidy and the growth potential better. Tea-oil forests which coverage is about0.8and lies on the hillside were made the grafting by using the method of abdominal bark by embedded in autumn, and the scion should collected timely, cut dry using the method of one-time cut in spring or autumn. Graft survival rate reached90%above average. Photosynthetic rate and light saturation point in three changing crown varieties, including Huashuo, Huajin and Huaxin, was both higher than ones not changing crown, but light compulsive point was much lower.2,Studies on techniques on tending for low yield stands of Camellia oleifera. Tending and improvement of tea-oil forest which age was less than30years and was built by excellent clones or fine family lack of management was made. The main foster measures were pruning and reclaiming. Trim can obviously promote the growth of trees, improve the canopy microclimate, enhance the photosynthetic rate, increase the fruit yields and improve fruit quality. The crown, effective optical proportion, net photosynthetic rate, single fruit weight, yield per plant and the weight of seed kernel trained to open-shaped system were0.10m2,62.5%,6.35μmol·m-2·s-1,39.21g,14.07kg and15.93g, respectively. They were higher respectively0.05m2,14.83%,2.03μmol·m-2·s-1,0.52g,2.02kg and0.30g than the dome-shape, and higher respectively0.09m2,38.32%,3.25μmol·m-2·s-1,6.2g,7.17kg and3.67g than that of control. Considering the above factors comprehensively, we can know that the open-shaped pruning was better than the dome-shape one. Different reclamation processing can improve the physical properties of the soil and production. Both soil bulk density and specific gravity in the soil between0-20cm were higher than the soil between20-40cm. In the same depth soil, different reclamation processing methods all reduced the soil bulk density and specific gravity, and improved total porosity and soil water content. Winter deep reclamation and summer light reclamation was the most efficient reclamation system, its shoot length, flower bud number and fruit number were higher respectively78.26%,85.53%and180.65%than the contrast treatment, and yield per plant increased by4.99kg. All reclamations can improve the yield of Camellia. Yield per plant stands of Camellia oleifera of winter deep reclamation, summer light reclamation, winter deep reclamation and summer light reclamation, without reclamation were7.11kg,6.24kg,8.63kg and3.63kg, respectively.3,Studies on regeneration and transformation of low yield stands of Camellia oleifera. Regeneration and transformation were conducted for the seeding and deteriorating tea-oil stand which age was more than50years. Study on cultivar arrangement and covering technologies of newly established forests was made. Researches showed that HuaJin in early flowering types is the preferred cultivar,'the Yongxing Martin dates7608'can be used as the pollination tree. In middle flowering types,'HuaShuo' and'HuaXin' were the preferred cultivar, and'HengDong17''HuaShuo''HuaXin'and'XiangLin1'can be used as the pollination trees. Covering straw and eco-pad can make the surface temperature fall by6-8℃in summer and the incidence of root rot40%-45%. But film mulching increased the surface temperature and incidence of root rot. Different covering methods can improve the seedling survival rate and growth. Overall, the best method is covering eco-pad, the second is covering straw method and the effect of film mulching was much poor. The survival rate of planting using biennial seedlings was higher than one with the annual seedlings, growth increment larger, incidence lower and resistance stronger.