Research Of Seedling Cultivating And Transplanting Under Plastic Mulching In Burley Tobacco In Dazhou

Sichuan dazhou is one of the main producing areas of burley tobacco in our country,but xuan han, which is the main producing areas in dazhou burley tobacco production areas in especial,often encounter low temperature and sunlight shortage for a long time during growing seedling period and the seedlings grow slowly, most tobacco area can not grown up seedlings on time during suitable period for transplanting and the seedling rate was low, which lead to delay of tobacco seedling transplanting and often be endangered by low temperature and rainy weather at later growth and air-curing stage of burley tobacco,which seriously affect the yield and quality of tobacco leaves. In order to provide basis for the choice of the ways of burley tobacco seedling cultivation and the establishment of technology system of the transplanting under plastic mulching in burley tobacco, this paper carried out a research of tobacco seedling cultivating and transplanting under plastic mulching in burley tobacco. Test results were as follows:1. Research of seedlings cultivating in burley tobacco.The effects of different seedling ways(floating system, shallow water floating system, seedling nursing on moist trays, plate airing and seedbed fermentation floating system) and the treatment of different centralized-pregermination-time on the growth and physiological and biochemical indexes of burley tobacco were studied. The temperature of water and media was recorded, growth period was investigated, the agronomic characters and physiological and biochemical indexes were measured and the seedling cost was analysed. The results showed that:the water temperature raised by 4.5degrees centigrade by seedling nursing on moist trays, media temperature raised by 2.0degrees centigrade by plate airing, seedbed period shorten by 7 days and 6 days by 3cm shallow water and plate airing. The germination rate and seeding rate and seedling rate were higher than the conventional contras significantly;The number of leaves and max leaf length and width of seedling nursing on moist trays were better, the root of plate airing was the best in the root period. The number of leaves and secondary root, the above and belowground dry weight, chlorophyll content, root activity and SOD activity were not different between treatments and control, aboveground fresh weight of seedbed fermentation were better, two lateral root, underground fresh weight, nitrate reductase activity and sound seedling rate were best in the seedling stage. The lowest cost of seedling nursing in shallow water and control was 696 yuan/hm2, and the one of seedbed fermentation was highest,576 yuan/hm2 more than floating system. In treatments of delayed 10d and 15d seeding and centralized-pregermination, all of treatments of pregermination until budding(T2,T6)and pregermination until seedling(T.3;T7)and pregermination until small-cross period(T4,Tg) sprout and grow up seedling early, the seedbed period shorten 10-13d than conventional contrast, the germination rate and seeding rate were higher than conventional contrast and other treatments, The plant height, max leaf length and width, dry weight and fresh weight of seedlings of treatment by T4 were higher than the conventional contras significantly in the root period. The agronomic traits and physiological and biochemical indicators had no significant differences compare with the conventional contras, even some of those were batter than the the contras.The cost of centralized-pregermination until the budding or the seedling or the crosses was separately higher than the contras by 627yuan/hm2,702yuan/hm2,933yuan/hm2.2. Research of transplanting under-plastic mulching in burley tobacco.This paper started a research on which seedling-age to transplant,which period to transplant, what size for hole, comparing the transplant mode contrast of low-medium-seedling and the conventional control, The results showed that:The effects of the growth period and agronomic traits and yield of tobacco plant of different treatments of seedling-age,which results showed that the six leaves with one sprout treatment grow fast after transplanting and went to rosette stage early. The plant height and the max leaf length were better than others in rosette stage. However, each treatment had no significant difference of agronomic characters in the fast growing period and the mature stage. There was no significant differences among three treatments in the average yield.The effects of the growth period and agronomic traits and yield of tobacco plant of different treatments of different period(4.15,4.20,4.25,4.30), which results showed that the treatments of transplanting at 4.25 shorten field period distinguish 2-4d.Part of the average of those agronomic traits were higher than the contrast and the treatment of transplanting at 4.30 in rosette stage and fast growing period.The average of agronomic traits between all treatments and the contrast had small difference in the mature stage and there was no significant differences in the average yield.The results of different size of hole to transplant under plastic mulching show that the growth period of single-hole treatment advanced by 3～5d,also a part of agronomic traits detas and the average yield of single-hole treatment were significantly higher than the three-holes treatment, but that had no significant differences with the double-holes treatment.In the study of comparing transplant mode of low-medium-seedling treatment and the conventional control,the results show that the whole date of the growth period and agronomic traits and the average yield all had no significant differences between low-medium-seedling treatment and the conventional control, the same as those average.