| Flue-cured tobacco in Panzhihua has attracted cigarette manufacturers’ great attention because of its unique Fen-flavor style, and Panzhihua has become a key area to develop good quality flue-cured tobacco in China. Yunyan 97 is a newly introduced cultivar in Panzhihua, its law of requiring fertilizer (especially the coordinated supply and reasonable use of NPK fertilizers) in special environments needs further investigating. This research adopts quadratic orthogonal rotation composite design of three factors and five levels. A field experiment was carried out to study the NPK fertilization effects of Yunyan 97 in Pingdi Town of Renhe District, Panzhihua City. By counted and evaluated the agronomic traits, economic benefits and chemical quality of Yunyan 97, By counted and evaluated the Yunyan 97 agronomic traits, economic benefits and chemical quality, the most optimal application rate of NPK fertilizers was worked out for Yunyan 97 growing in flat areas. The main results were as follows:1. The effects of combined application NPK fertilizers on the agronomic characters of Yunyan 97When the ranges pure nitrogen, pure phosphorus and pure potassium were 1.75～12.25kg/667m2,1.40～9.80kg/667m2 and 4.90～34.30kg/667m2, increasing the application amount of NPK fertilizers can promote the growth of Yunyan 97 in some extent, it can also increase the stalk width and the leaf area coefficient of tobacco plant. And nitrogen and potassium fertilizers greatly affect the agronomic characters of tobacco plant during the whole growth and development. While phosphorus fertilizer show its impact mainly in topping period, it can help to increase the stalk width and the leaf area coefficient of tobacco plant.2. The effects of combined application of NPK fertilizers on the economic benefits of Yunyan 97When Xi ranges from -1.682 to 1.682, the economic values of Yunyan 97 firstly increase and then decrease with the increase of the application rate of NPK fertilizers. And nitrogen and potassium fertilizers have significant influence on the yield and the production value of Yunyan 97, while phosphorus fertilizer greatly affected the proportion of middle and superior tobacco leaves.Under the test condition in 2010, when the yield, production value and the proportion of middle and superior tobacco leaves reached 170kg/667m2,3000yuan/667m2 and 80%, the specific application fertilizer scheme were: supplying nitrogen fertilizer 5.55-6.88kg, phosphate fertilizer 5.22-6.75kg and potassium fertilizer 16.58-22.62kg per 667m2.3. The effects of combined application of NPK fertilizers on the chemical quality of Yunyan 97The application rate of NPK fertilizers had different influence on different chemical quality index. Among them, the total nitrogen, nicotine, potassium content, the ratio of potassium to chlorine and composite index of Yunyan 97 firstly increase and then decrease with the increase of the application rate of NPK fertilizers. While the ratio of N to alkali, the contents of total saccharides and reducing sugar and ratio of sugar to alkali were greatly affected by nitrogen fertilizer. When the potassium content exceeded 2%, the composite index of chemical quality was above 0.8, The specific application fertilizer scheme were:supplying nitrogen fertilizer 6.03-7.96kg, phosphate fertilizer 5.49-7.38kg and potassium fertilizer 19.82～25.20kg per 667m2.4. The best fertilization model of NPK for Yunyan 97 and the verification and demonstration of the formulaTherefore the paper combines experimental results,local concrete conditions,NPK ratio, reduction applied fertilizer while increasing efficiency and soil environmental sustainability,etc.the application fertilizer scheme for Yunyan 97 growing in flat areas were worked out:the applying contents of nitrogen, phosphate and potassium were 6kg,6kg and 22kg per 667m2 respectively. The fertilization formula has been proved to be feasible by the researchers in 2011. And in 2012, this fertilization formula has been promoted on a large scale by the local tobacco companies. |
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