| In order to improve the quality and style of fiue-cured tobacco in a whole period of field growth, the status and comprehensive evaluation of soil fertility in Neixiang hills tobacco-growing areas, and the effects of nitrogen on the tobacco quality were reserched.The main research results are as follows:1.The average soil p H value of soil in Nyangyang hills tobacco-growing areas is 6.9, ranged from 5.4 to 8.9.The soil area with suitable p H with value of 5.5 ~7.5 accounts for 70.4%,25.7% of soil p H value is higher than 7.5,and only 3.9% of soil p H value is less than 5.5.Therefore,The proportion of the rural tobacco soil slightly acidic and neutral soil accounted for the largest,p H value of most of the soil is suitable for the basic requirement of producing the high quality tobacco.2.The average soil Organic Matter(OM) in Neixiang hills tobacco-growing areas is 13.79 g/kg. There are 75.4% of soil samples is in a low level, 17.1% of soil samples is in lack of organic matter, 7.5% of soil samples is in middle level, there is almost no soil organic matter value is higher than 30 g/kg. Visible, soil organic matter content in this area is generally low.3.The average soil total nitrogen in Neixiang hills tobacco-growing areas is 0.92 g/kg.There are only 3.2% of soil samples with the content of soil total nitrogen between 0.0~0. 5 g/kg, soil total nitrogen between 0.5 ~ 1.0 g/kg respectively reached 63.0%, soil total nitrogen between 1.0 ~ 2.0 g/kg respectively reached 33.8%, there is almost no soil total nitrogen content is higher than 2.0 g/kg. Visible, soil total nitrogen content in this area is generally high.Therefore,we should determine the appropriate amount of nitrogen based on the total nitrogen content.4.The average soil available potassium in Neixiang hills tobacco-growing areas is 17.68 mg/kg. There are only 30.4% of soil available potassium content is less than 10 mg/kg, soil available potassium between 10 ~ 20 mg.kg-1 respectively reached 37.8%, soil available potassium between 20~40mg.kg-1 respectively reached 24.7%, soil available potassium between 40 ~ 80 mg.kg-1 respectively reached7.1%; The average soil available K and tardo K in this areas are 174.61 mg/kg and 972.87 mg/kg. Visible, the level of soil available potassium, available K, tardo K content in this area are generally high.5.The average soil Valid Fe value of soil in Neixiang Huanggang hills tobacco-growing areas is 21.15 mg/kg with Coefficient of variance(CV)of 48.13%,ranged from 1.07 to 65.30 mg/kg; The average soil Valid Mn value of soil is 16.65 mg/kg with Coefficient of variance(CV)of 70.59%,ranged from 0.00 to 81.58 mg/kg; The average soil Valid Cu value of soil is 1.23 mg/kg with Coefficient of variance(CV)of 45.88%,ranged from 0.05 to 6.08 mg/kg; The average soil Valid Zn value of soil is 1.04 mg/kg with Coefficient of variance(CV)of 86.06%,ranged from 0.00 to 9.90 mg/kg. Visible, the level of four trace elements are generally high but unevenly distributed.6.The soil fertility could be classified four ranks by cluster analysis. Rank 1 was of the highest soil fertility with comprehensive scores≥0.5, including 142 soil samples, representing 10.97% of the total sample;Rank 2 was of higher soil fertility with comprehensive scores 0.0-0.5,including 497 soil samples, representing 38.38% of the total sample;Rank 3 was of the medium soil fertility with comprehensive scores-0.5-0.0, including 522 soil samples, representing 40.31% of the total sample;Rank 4 was of low soil fertility with comprehensive scores≤-0.5, including 134 soil samples, representing 10.35% of the total sample. High fertility accounted for 49.30% of the total sample, low fertility sample only 10.35% of the total sample, the medium fertility accounted for 40.31%, indicating a higher level of overall soil fertility in the Neixiang hills tobacco-growing areas.7.With the increase of the amount of nitrogen, the plant height of flue-cured tobacco, stem girth, maximum leaf length, width of the largest leaf showed increasing trend, but the difference was not significant; pitch, effective number of leaves had no significant difference; among the different varieties, plant height, maximum leaf length, maximum width all have significant differences; stem girth, pitch, effective number of leaves had no significant difference. The total dry matter of root, stem and leaf nitrogen accumulation were increased with the increase in the amount of. With the growth period, the variety of agronomic traits and dry matter accumulation were gradually increased, to 80 D tends to be stable, mainly for the internal chemical composition change.8.Plastid pigment content of different varieties of flue cured tobacco leaves increased with the days of transplanting showed a single peak curve, and it increased gradually before the 50 D, to about 50 D reached the maximum value, after transplanting 80-95 d down to the lowest point and tends to be stable. With the increase of the amount of nitrogen, total chlorophyll was increased gradually, and the difference reached the significant level, but there were no certain rule on the effects of carotenoids.9.In a certain range, increasing the amount of nitrogen fertilizer can increase the tobacco output value and average price., neutral aroma substances can be increased In a certain degree. Among the different varieties showed that Yuyan No. 7 has high price and output under the application amount of nitrogen 22.5kg/hm2, Yunyan 87, K326 and Yuyan No. 10 has high price and value under the application amount of nitrogen 37.5kg/hm2, and the content of aroma components of each variety also have higher levels in the amount of nitrogen.10.Application of the increase of amount of nitrogen can promote nitrogen accumulation contained in nicotine, total nitrogen and protein in leaves, and the sugar, total sugar content is reduced accordingly. Yuyan No. 7 in the amount of nitrogen 22.5kg/hm2 level and other varieties in applying amount of nitrogen 37.5kg/hm2,the chemical components of flue-cured tobacco leaves coordination the best, the high and low nitrogen treatment perform poor coordination.11.With the increasing of the amount of nitrogen, leaf weight, leaf thickness increased gradually, tension, filling value, including infarction rate law is not obvious, and the three indicators of Yuyan 7 in the dosage of 22.5 kg / hm2 nitrogen have a higher numerical, and the other three species have higher level in 37.5 kg / hm2 nitrogen dosage Leaf quality, leaf thickness increased gradually with the increase of leaf position, and the tension, stem ratio, the fill value decreased slightly with the increasing of the leaf position.12.The amount of nitrogen also has certain effects on the sensory quality, with the increase of nitrogen amount, the momentum increases. Yuyan 7 mainly perform pure aroma quality, aroma quantity is sufficient, miscellaneous less gas low stimulation and good combustibility, K326 mainly perform comfortable aftertaste, smoke concentration, comfortable aftertaste, better ash. Yuyan No. 7 in 22.5 kg/hm2 nitrogen dosage had the highest value, other varieties had the highest value in the 37.5 kg/hm2 nitrogen dosage. |
PDF Full Text Request