Effects Of The Nutrient And Biology Of Different Soil Types On The Quality Of Flue-cured Tobacco

In order to find out the effects of agrotype on growth and quality of flue-cured tobacco, the differences of nutrients and biological characteristics between different soils(paddy soil, purple soil and red soil) were studied in this research through field experiment method. The main results are as follows:1The paddy soil and purple soil were loamy clay in texture and their pH was alkaline, while the red soil was clay loam in texture and its pH was slightly acidic. Before planting tobacco, the differences of the contents of urease, sucrase, alkaline phosphatase, bacteria, actinomycetes, fungus and available potassium were extremely significant (P<0.01) between these three soils. The differences of the contents of catalase, organic matter, total nitrogen, available nitrogen, available phosphorus, total potassium were significant (P<0.05) between these three soils. The biological characteristics and nutrient contents in soil had certain influence on most physical and chemical indexes of flue-cured tobacco. Bacteria effect the most significant in microorganisms, while nutrient had the most significant in physical and chemical indexes.2The contents of soil nutrient declined rapidly after topping,、The content of urease and nitrogen were high in early times well low in later time, which would conducive to tobacco leaves maturity, denitrification and improve the content of potassium, it also was favor in forming a good quality of tobacco. Alkaline phosphatase, urease activities were high, and catalase activities were low during whole tobacco growth stages in paddy soil, while the high contents of nitrogen and phosphorus in maturity period would cause the high content of nitrogen compounds. The catalase activities were higher in red soil, besides other biological characteristics were similar to purple soil. But the enzyme activities and microbial quantities and nutrient contents were all significantly lower than those in purple soil.3In purple soil tobacco grew fast in prosperous long-term but matured slowly, the chemical composition proportion of tobacco leaves was concerted. The content of potassium was rich but the proportion of midrib was also high. The dry matter, leaf thickness and the unit leaf area were significantly lower than the other two types of soil. Tobacco from paddy soil grew too fast in maturity. The dry matter, leaf thickness and the content of nicotine and total nitrogen were too high owing to the difficulties in denitrification. The growth of flue-cured tobacco in red soil was relatively weak, the physical properties was similar to the tobacco leaves in paddy soil. The content of sugar was high while nicotine was in low level, the ratio of sugar/nicotine and volatile acid/volatile alkali was significantly higher than tobacco in paddy and purple soil. The evaluated results by sense organ showed that one of the main reasons made diversity in growth and quality of flue-cured tobacco from different soils was they had differences of nutrients and biological characteristics.