Studies On Yield, Quality And Nutrient Characteristics Of Flue-cured Tobacco In Zunyi

According to such problems as excessive fertilizer, low utilization rate of fertilizer, tobacco qulity decrease and style vanished, which exists in the system of fertilization techniques for flue-cured. In the present study, the methods of research covered investigation, pot experimenting, lerching chamber experimenting and field experimenting. The characteristics about nutrition environment, relationships between tobacco leaf's quality and their mutual were studied. Then nutrition characteristics of tobacco and N,P,K utilization, leaching and transformation were deeply studied. Finally, the effect of combined application of organic manure and fertilizers was studied in order to explore nutrient use efficiency improvement. The main conclusions are as follows:1 Basic characteristics of quality of tobacco in ZunyiThe average yield of tobacco in Zunyi is only 1846.63 kg/hm2 and the output is 18,000yuan/hm2 and 8.87yuan/kg. For the leaves in the middle part, the contents of total nitrogen and protein in average were 1.91%and 6.72%, the content of nitrogen are between 1.5%-2.5%mostly and nearly 70%of tobacco leaf's protein was between 6%-7%. The contents of total sugar and reducing sugar in average were 27.70%and 22.20%respectively, less than 50%sample was in the suitable range. Both the content of nicotine and K were rather bad,3.14%and 1.91%respectively in average, of which the suitable samples accounted for only 20%and 13.11%respectively. The harmony of quality indexes of tobacco leaf should be improved. For example, the Shmuk values were rather high, which in average was 4.16 and the suitable samples only take a part of 1.42%, meaning the ratio of total sugar to protein were not in harmony. The ratio of total nitrogen to nicotine was low that in average was 0.63,of which the suitable samples accounted for 4.53%. The ratio of total sugar to nicotine in average was 7.58 and the suitable samples reached 50%, which resulted in gentle taste and tame aroma for parts of tobacco leaves. The ratio of potassium to chloride was suitable that in average was 5.44 and suitable samples accounted for 73.37%.2 Basic characteristics of nutrition environment of soilFor the tobacco growing soils, the content of organic matter in average was 25.36 g/kg:the soil samples with content between 20-30 g/kg accounted for 53.37%, and 21%of the samples with a content exceeding 30 g/kg. The pH in average was 6.04:the samples with pH between 5.0-7.0 accounted for 88.48%. The total nitrogen content in average 1.89 g/kg and nearly 90%of the sample was between 1-2.5 g/kg. The contents of nitrate and ammonium nitrogen in average were 6.03 mg/kg and 12.60mg/kg respectively:more than 80%of soil samples nitrate nitrogen content less than 10mg/kg and 75.53%of soil samples ammonium nitrogen content less than 15 mg/kg. The total phosphorus content in average was 0.66 g/kg, and available phosphorus was 17.57mg/kg. The content of total phosphorus was chiefly between 0.5-1.0 g/kg, accounted for 64.04%, and nearly 50%soil sample available phosphorus content more than 15mg/kg. The content of total K in average was 21.40 g/kg, and about 50%of soil total potassium content more than 20 g/kg. The contents of slow available potassium and available potassium in average were 395.65mg/kg and 164.75 mg/kg respectively.3 Relationship between nutrition environment and tobacco leaf's quality in ZunyiThe results of correlation analysis indicated that the leaf quality was correlated with the nutrients of tobacco-growing soils. The soil pH was highly significant positively correlated with leaf total sugar and leaf protein, whereas negatively correlated with leaf reductive sugar. The soil organic matter was only significant negatively correlated with leaf K. The total nitrogen was positively correlated with leaf quality. It is highly significant positively correlated with leaf total nitrogen, leaf nicotion,leaf protein and leaf chloride; and significant positively correlated with potassium/chloride. The ammonium nitrogen was significantly negatively correlated with leaf K, whereas positively correlated with sugar/protein. The total phosphorus was significantly positively correlated with nicotine, protein and significant positively with potassium, whereas negatively with total sugar/protein, total sugar/nicotine. The available phosphorus was significantly positively correlated with total sugar, whereas negatively with total nitrogen. There were significantly negative correlations among total potassium, reductive sugar and total nitrogen, whereas significantly positive correlations among slow available potassium, reductive sugar, total nitrogen and potassium, chloride, and among available potassiun,total sugar, total nitrogen, nicotine, protein and chloride. There were significant negative correlations among water-dissolving chloride, reductive sugar, nitrogen and protein.4nutrients utilization of tobaccoThe accumulation of N,P,K of six flue-cured tobacco varieties:K326,Jinhai 1,Nanjiang 3,Zunyan 6, Yunyan 85 and 87,was gradual increase as seedlings grew up. The nitrogen accumlation were 8.63 g/plant (Jinhai 1),9.75 g/plant (Nanjiang 3),7.75 g/plant (Zunyan 6),6.25 g/plant (K326),6.85 g/plant (Yunyan 85),7.17 g/plant(Yunyan 87). The phosphorus accumlation were 0.71 g/plant (Jinhai 1),1.1 lg/plant (Nanjiang 3),0.78g/plant (Zunyan 6),0.63 g/plant (K326),0.68g/plant (Yunyan 85), 0.76 g/plant(Yunyan 87). And The potassium accumlation were 9.91 g/plant (Jinhai 1),11.11 g/plant (Nanjiang 3),9.38 g/plant (Zunyan 6),6.63 g/plant (K326),6.77 g/plant (Yunyan 85),6.81 g/plant(Yunyan 87).The absorption condition of N,P,K by tobacco showed low-high-low trend. The absorbing peak of N was the 60-90d after transplant, and there was little difference in absorbing nitrogen bewteen varieties. The absorbing peak of P was the 70-90d after transplant, and there was great difference in absorption rate and the time reached absorbing peak. Zunyan 6 and Yunyan 85 reached absorbing peak at 70 d after transplant, Nanjing 3 reached at 75d, K326 reached at 85d, and Jinhai 1 and Yunyan 87 reached at 90d. More than 90% potassium was absorpted before 90d after transplant. For all of them but Jinhai 1.,the absorption peak rise at 40-45d after transplant, and potassium absorption completed 75%-85% at 60 d.The characteristic nutrient supply of flue-cured tobacco-grown soil showed low-high-low trend, but supply was much earlier than the absorption of tobacco. The peak of available nutrients supply reached at 30d after transplant, and then rapidly decreased.There was a positive correlation between ground runoff and rain prescription, the highest ratio of ground runoff to rain prescription appeared at early period of tobacco growth and then a gradual decrease as seedlings grew up. The concentration of NO₃, which similar with K+, was much higher than NH4+ but no phosphorus was detected in leaching solution. The rates of leached nutrients accounted for over than 60% of nitrogen and about 1/4 of potassium supplied. In addition, the amount of nutrient leached was related to soil nutrient content (nitrate) and rain prescription (potassium). The apparent utilization rate of fertilizers was 42.71%(nitrogen),20.77%(phosphorus) and 34.48%(potassium), respectively. The highest amount of phosphorus, less potassium and smallest nitrogen fertilized remained in soil.After three years of successive cropping, overuse of fertilizer led to P K N accumulation in soils. Available N content was obviously increased:nitrate and ammonium nitrogen contents were increased 2.26 times and 4.97 times than that of the original soil.The unutilized fertilizer P was transformed mainly into Al-P, increased Al-P content about 6 times after 3 years at plow soil layer followed by Fe-P,increased by 2.30-folds at the end of cultivation. However, O-P and Ca-P fluctuated slightly. At the end of continuous tobacco cultivation, the average contribution of each fraction to the increase in total inorganic P was A1-P (23.39%), Fe-P (39.36%), O-P (21.76%) and Ca-P (15.47%), whilst it was O-P (38.94%), Fe-P (30.04%), Ca-P (24.19%) and Al-P (6.82%) in original soil. Cultivation increased H₂O-K content about 3.92 times after 3 years. NH4Ac-K and HNO3-K were also increased by 3.92-folds and 4.70-folds at the end of cultivation. At the end of continuous tobacco cultivation, the average contribution of each fraction to the increase in total inorganic K was H2O-K (17.72%), NH4A_c-K (44.93%) and HNO₃-K (37.34%), whilst it was H₂O-K (17.31%), NH4A_c-K (48.81%) and HNO₃-K (33.88%) in original soil.5 The yield and quality of Flue-cured tobacco, quality of soil and nutrient utilization under different tobacco cropping modalsThe quality of tobacco and soil was same as the basic characteristics in Zunyi. The quality of tobacco was bad and the contents of nutrient in soil were very rich. Neither continuous cropping nor tobacco-corn rotation can make any difference in yield, quality of tobacco and soil nutrient. Six years pot experiment of continuous tobacco cropping showed the decrease in the yields of tobacco leaves in general, and variation in the amount of the yield reduction in variable soils in particular. There was no significant difference in the yield of the leaves within the first three years and then decrease after that in the soil suitable for continuous cropping in contrast to the unsuitable one in which the yield constantly reduced during the process. Available nutrients were increased variably, and the amount of increment showed in the sequence:phosphorus> potassium> nitrogen.There was no obvious difference between continuous cropping and rotation in yield, output value and disease occurrence under conventional fertilization, also soil nutrient content. All of Total N,P,K and available N,P,K, were increased than that in original soil. However, reduce the mount of ferilizer in corn, enhanced yield and output value of tobacco significantly, and obviously decreased disease occurrence. The contents of available nutrient in soil had different changes between continuous cropping and rotation, available N was increased a little in rotation system, whereas increased about 3.7 times in continuous cropping system. Available P content was obviously increased, increased by 2-folds and 4.71-folds respectively, also increased Available K content,about 2 times,3 times respectively.Apparent utilization rate of fertilization was obviously increased after decreased the fertilization. The apparent utilization rate of tobacco fertilizers in continuous cropping system was 25.01% (nitrogen),17.70%(phosphorus) and 24.67%(potassium), respectively, whilst it was 41.48% (nitrogen),29.91%(phosphorus) and 34.63%(potassium) in rotation system. The apparent utilization rate of corn fertilizers was 81.40%(nitrogen),103.86%(phosphorus) and 99.81% (potassium), whilst it was 41.53%(nitrogen),49.22%(phosphorus) and 64.93%(potassium) in original system.6 High-efficient and multifunctional biological fertilizer and chemical fertilizer cooperating applicationThe combined application of High-efficient and multifunctional biological fertilizer and chemical fertilizer can decrease the fertilization, enhance utilization rate of fertilizers, and also can promote the growth of tobacco plant and improve the quality of tobacco. It also could activate soil nutrient and increase the biological availability of soil nutrient. Application of High-efficient and multifunctional biological fertilizer can change the curve of nutrient supply, which can satisfy the requirement of tobacco even better, and could reduce cost and increase economic benefit.