Effects Of Nutrients Management On Physiological Characteristics And Quality Of Dark Sun-cured Tobacco In Jiaohe

Aiming at the problems of too high tobacco leaf production,insufficient oil contents and aroma quantity resulted in the improper nitrogen application and chaotic type of fertilization in the sun-cured producing area of Jiaohe in Jilin Province,The effects of nitrogen application on physiological characteristics and quality of different varieties of dark sun-cured tobacco,soil biochemical characteristics,nutrient absorption and utilization of dark sun-cured tobacco and yield and quality of tobacco were studied.The main findings are as follows:1.Increased application of nitrogen fertilizer can increase the content of chlorophyll and carotenoid in tobacco leaves of two varieties,improve the activity of key enzymes of carbon and nitrogen metabolism of dark sun-cured tobacco leaves during the growth period,and promote the growth and development of tobacco leaves;However,when the nitrogen application amount was 112.5kg/hm2,the nitrogen metabolism of tobacco plants was too vigorous in the later growth stage,resulting in the greening and late ripening of tobacco leaves.The yield of dark sun-cured tobacco increased with the increase of nitrogen application,but the proportion and average price of high-grade tobacco decreased when nitrogen application was too high.The economic characters of tobacco leaves of both varieties were best when the nitrogen application amount was 90kg/hm2.2.With the increase of nitrogen application,the content of total nitrogen and nicotine in the leaves of the two varieties of dark sun-cured tobacco increased,while the content of total sugar and reducing sugar decreased.After cuerd,the total amount of neutral aromatic substances in tobacco leaves increased with the increase of nitrogen application,but excessive nitrogen application would lead to the decrease of aroma quality and aroma quantity of tobacco leaves,and the highest sensory quality of tobacco leaves was treated with the amount of nitrogen of 90kg/hm2.3.Different types of fertilizers have different effects on soil enzyme activities,soil available nutrients and nutrient absorption and accumulation of tobacco plants.After cake fertilizer was applied into the soil,due to the low temperature in the early growth stage of the field and the continuous drought for many days,the soil moisture content was low,the soil organic carbon and organic nitrogen mineralization rate was slow,in the middle and late growth stage,the temperature increased,the rainfall also increased,and the mineralization rate of the cake fertilizer was accelerated.The application of cake fertilizer can improve the soil enzyme activity,promote the transformation of soil organic matter,improve the content of soil available phosphorus,available potassium,nitrate nitrogen and ammonium nitrogen,and provide sufficient nutrients for the growth of tobacco plants.Among the four fertilization measures,cake fertilizer and tobacco professional fertilizer combined application(T4)had the best effect.4.The agronomic indexes of tobacco plants treated with cake fertilizer were significantly higher than those treated with conventional fertilizer in the middle and later growth period,the application of cake fertilizer was beneficial to the development of root system of tobacco plants,and the accumulation amount of mineral elements of tobacco plants treated with cake fertilizer was significantly higher than that of conventional fertilizer treatment,among which the combination of cake fertilizer and tobacco fertilizer(T4)had the best effect.5.With the application of cake fertilizer,tobacco leaf could successfully complete the conversion process from nitrogen metabolism to carbon metabolism in the later growth stage of field.The activity of invertase and amylase in tobacco plants treated with cake fertilizer was higher than that of conventional treatment in the later growing period of field field,which was more beneficial to the tobacco leaves ripening and yellowing.At the same time,it can effectively adjust the coordination of chemical components in tobacco leaves,increase the content of siberane,phenylalanine and other aroma substances in tobacco leaves,improve the proportion of first-class tobacco,increase the aroma and taste of tobacco leaves,reduce miscellaneous gas and irritation,so as to improve the quality of tobacco leaves.To sum up,the appropriate nitrogen fertilizer application rate for Piaohe 1 and Piaohe 2 is 90kg/hm2.The aroma quantity and overall sensory quality of tobacco leaves with tobacco special fertilizer were better than conventional fertilization.The combination of soybean cake and tobacco fertilizer was more beneficial to improve the internal quality of tobacco leaves.