Study On Transplanting Techniques Of Flue - Cured Tobacco With Special Features In Longjiang Region

Based on a flue-cured tobacco variety Longjiang 911, and with using conventional mulch transplanted tobacco as control group, the influence of different transplanting techniques(high-stem deep-seated transplanting, well-cellar transplanting, transplanting without covering soil) on photosynthetic characteristic of flue-cured tobacco leaves, growth and development of tobacco plant, morphological characteristics of root system, rhizosphere microbes, and yield and quality of tobacco was studied. Results are as follows.1. Compared with conventional mulch transplanting, high-stem deep-seated transplanting improved the chlorophyll content and photosynthetic capacity of flue-cured tobacco leaves. For upper, middle and lower tobacco leaves, the chlorophyll content increased by 9.5%, 48.2% and 2.3% respectively; the net photosynthetic rate increased by 21.5%, 16.2% and 15.4% respectively; and the water use efficiency(WUE) increased by 18.4%, 18.5% and 7.9% respectively. The growth and development of tobacco plant was improved, the rate of survival of tobacco transplant was raised by 1.4%. The stem girth of the tobacco plant in dome period increased by 1.05 cm, the number of remained leaves increased by 0.72 pieces, the length of lower leaves increased by 5cm, the length of middle leaves increased by5.31 cm, the upper leaves increased by 4.06 cm, the LAI of middle leaves before harvesting increased by 3.31%, and the LAI of upper leaves before harvesting increased by 13.49%. The growth and development of the root system of the tobacco plant was improved. The root vigor increased by 10.9% to 64.0%; the number of root tips increased by 4.0% to 11.0%; the length of the root increased by 3.7% to 19.0%;the volume of the root increased by 1.6% to 32.9%; the surface area of the root increased by 3.7% to 26.3%; the projection area of the root increased by 3.7% to26.3%; and the accumulation of dry matter of the root increased by 1.7% to 12.9%.The number of rhizosphere microbes increased. In growing period, the number ofrhizosphere bacteria increased by 42% to 139%; the rhizosphere actinomycetes increased by 27% to 110%; and the rhizosphere fungus increased by 100% to 300%.The yield and quality of cured tobacco leaves also increased. The rate of high-class leaves increased by 4.97%, while the rate of orange colored leaves increased by4.32%. The output value per hectare increased by RMB 338.55. However, the coordination of chemical ingredients of tobacco leaf was ordinary. The total score of the chemical ingredients indexes of cured tobacco leaves was relatively lower.2. Compared with conventional mulch transplanting, well-cellar transplanting technique improved the chlorophyll content and photosynthetic capacity of the upper and middle leaves. It facilitated the growth and development of the tobacco plant,raised the survival rate of transplanted tobacco by 1.4%, and helped upper and middle leaves to unfold. The length of middle leaves increased by 3.32 cm, while the length of upper leaves increased by 5.36 cm. The number of rhizosphere microbes increased.In growing period, the number of rhizosphere bacteria increased by 10-319%; the number of rhizosphere actinomycetes increased by 8% to 230%; the number of rhizosphere fungus increased by 69% to 230%. The yield and quality of cured tobacco leaves was improved. The rate of high-class tobacco leaves increased by 3.89%. The output value per hectare increased by RMB 387.73, assuming the price of tobacco leaves increased by RMB 0.95 per kilogram. The coordination of chemical ingredients of the cured tobacco leaves was preferable. The total score of evaluation for upper and middle tobacco leaves was 70.4 and 68.8 respectively and increased by29.2% and 14.9% respectively in comparison with that of conventional mulch transplanting.3. The technique of transplanting without covering soil showed little promotion on photosynthetic characteristic of flue-cured tobacco leaves, growth and development of the tobacco plant, morphological characteristic of root system,rhizosphere microbes and yield and quality of tobacco. Its performance was similar to that of control.