| Equilibrium fertilization is one of methods of fertilizering which depends on trophic situation of soil,theabsorption of various nutrients in different crops and the supplement of necessary nutrients, in ordertoobtain the most highest yield and the best ecnomic efficiency. Using flue-cured tobacco(Nicotianatabacum L.) as materials, this study investigates the effect of equilibrium fertilization on theyield andquality of flue-cured tobacco based on the soil and climatic resources of Anshun city. The resultswere asfollows:1,Basic conditions for tobacco-growing areas, meteorological factors, status of soil nutrients andquality of tobacco leaves were analyzed in Liuyang, Hunan province. The results showed that: (1) Inliuyang tobacco-growing areas, frost-free period was 222-241 d, accumulated temperature of =10℃was5123-5447℃, period of time with daily average temperature of =20℃was 140-160 d. The soil wasyellow-red with a hilly topography, slightly acid to neutral pH, and low Cl~- content. (2)The nutrientcontent of the soil showed a big variation in locations. The contents of organic matter, total N, available Nand available P were rich in general; the content of total P was rich for half of the soil samples, and poorthe other half; the content of K was medium to low for most soil samples; the contents of mostmedium-micro elements were rich. But the contents of available B were obviously low, the contents ofexchangeable Ca and exchangeable Mg were poor, the contents of the water soluble Cl was rich for 2/3 ofthe soil samples, and poor the other 1/3.2,The study to different formulation of nitrogen showed that economical character of cured tobacco issignificantly improved, as the increasing of nitrogen application. In the condition of same amount ofnitrogen, organic-nitrogen is better than inorganic nitrogen. With the use of nitrogen increases, the outputand output value of tobacco in elemental area tends to rise. Also the organic-nitrogen is better thaninorganic nitrogen. Dealing with the whole, the chemical compositions in internal tobacco areuncoordinated, which may be related to out of employ of calcium, magnesium, phosphorus and otherfertilizers in the experiment. In particular, the lack of phosphorus has a great influence to the coordinationof total sugar, reducing sugar and ratio of sugar, and also affects the absorption of nitrogen element bytobacco paints.3,the effect of ratio of nitrate nitrogen to ammonium nitrogen(R_N) on agronomical character, economic and quality of flue-cured tobacco were studied. The results showed: 1) RN didn't influence the leaf width,leaf long, leaf area, yield, productive value and average price of flue-cured tobacco, but had significanteffect on grad composing, content of chemical component and the accumulation of N, K and CI. Withinlimited rang of R_N, the relations between yield, average price, yield of high grad tobacco, yield of low gradtobacco, nicotin, N, reducing sugar, Cl, amylum, volatile base and the quotient of ammonium would beendescribed by significant quadratic polynomial, and the relations between K and the quotient of ammoniumconformed to negative linear equation; 2)With a R_N of 75％:25％, the value of proportion of high &middle grad tobacco, content of nicotin, N, K, uptake of N and K/Cl were the highest, volatile base waslowest. When R_N was 25％:75％, N and amylum were lowest, and volatile base were highest. With 100％ammonium, reducing sugar, CI and amylum were highest, and K/Cl, nicotin and K were lowest. With100％nitrate, the content and uptake of N, K and Cl were the lowest; 3) Any RN, the content of nicotin, N,K, Cl and amylum satisfied the demand of high quality tobacco, reducing sugar was on the other wayround. Taking economy, nutrition utilization and chemical quality into consideration, the suitable R_Nwould be 54％:46％～50％:50％.4,five fertilizer application methods on growth, yields and quality of flue-cured tobacco were tested inLiuyang. On comparison, the results showed that "101" fertilizer method and bank-type row applicationmethod, especially "101" fertilizer method, could increase apparently the height, the cane, the leaf amount,the biggest single leaf area and the single leaf weight of tobacco, it was especially reasonable of theaccumulation of dry matter, thereby they could increase apparently yield, quality, the average price and therate of superior and medium tobacco leaf,of flue-cured tobacco.5,the effect of B on agronomical character, economic of flue-cured tobacco were studied. The resultsshowed that B didn't influence the leaf width, leaf long, leaf area and yield, but had significant effect ongrade composition, production value and average price. With 900～1500g/hm2 Borax being sprayed atrosette stage, production value, average price and upper grade tobacco leaf were respectively increased by1189.5～4095.0 yuan/hm2, 0.98-1.49 yuan/kg and 12.8-15.5 percentage points, and lower grade tobaccoleaf was decreased by 10.8-16.3 percentage points.
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