Studies On Phosphorus Nutrition Of High-quality Flue-cured Tobacco Production In Fujian Province

Simulation experiment with repacked soil columns, soil-culture, pot experiment, field experiment, sense appraisal of high grade leaf, field investigation were conducted to study the rule of the leaching lose and the transference of P fertilizer in different soils, suggested the index whether be rich or lack of P content in soil and tobacco leaf in Fujian tobacco planting area, and appraised the ability of soil to supply P in Fujian tobacco planting area.1．The result of an indoor simulating experiment with repacked soil columns showed that, under the amount of 80 mg/kg condition (P₂O₅) , the concentration of total P and dissolved P in soil columns leachates of calcium magnesium phosphate, Ca(H₂PO₄) ₂, (NH₄) ₂HPO₄, NH₄H₂PO₄ and KH₂PO₄ in the moist sandy land were very little, 0．020 mg/L-0．282 mg/L and 0．578 mg/kg-0．748 mg/kg respectively. Even if the content of soil available phosphate reached 64．40 mg/kg, the leaching ratio of 5 kinds of phosphate fertilizers was only between 0．235 %-0．721%, during the entire leaching period, the leaching ratio of phosphorus in fertilizer was very low.2．The result of the soil-culture indicated that, calcium magnesium phosphate applying in every kind of soil, with the time extension, the content of soil available phosphate increased gradually, and the soil had the highest amount of available phosphate and tended to stability in 80 days. The content of soil available phosphate gradually decreased after Ca(H₂PO₄) ₂, (NH₄) ₂HPO₄, NH₄H₂PO₄ and KH₂PO₄ were applied in the soils. The change of the P content was slight and tended to be stabilized. The ratio of clench in various soils was in the following order: the yellow mud field >the grey yellow mud field >the moist sandy land >the lime marl field.3．The correlation coefficient of flue-cured tobacco P uptake and soil available phosphate by Olsen method,0．03 mol/LNH₄F-0．025 mol/LHCl method,M3 method and 0．05 mol/LHCl-0．0125 mol/LH₂SO₄ method were 0．974,0．983,0．972,0．963 separately, being extremely remarkably positive in correlation (r_0．01 =0．798) . Olsen method is generally used in flue-cured tobacco production practice at present. So, soil available phosphate that the digestion determined with Olsen method is the index of soil provides phosphorus ability in this paper.The result of the pot experiment indicated that, in flourishing stage, if the level of soil available phosphate was deficient, then tobacco leaf had vacant phosphorus symptom, growth was blocked and plant was undersized. Blades were rigid on middle lower part and appeared necrotic blots.The content of chlorophyll and protein were low, the flue-cured tobacco leaf blade was easily senile. In the prosperous long-term of flue-cured tobacco, considering the growing trend, the physiological biochemistry target, and the content of phosphorus in the leaf tobacco of each processing, might initially consider phosphorus content was less than 0．17% for to lack the phosphorus, 0．17%-0．22% for the phosphorus to be insufficient, was more than 0．22% to be sufficient for the phosphorus element in lower part leaf. Fujian tobacco planting area, less than 10 mg/kg of soil available phosphate, then the phosphorus deficiency was grave, 10 mg/kg-20 mg/kg was phosphorus deficiency, 21 mg/kg-35 mg/kg was medium; more than 35 mg/kg was rich.4．The field test result indicated that, when the content of soil available phosphate was lower (13．02 mg/kg), medium(25．11 mg/kg), higher(36．80 mg/kg), the proper amount of applicationof phosphate fertilizer (P₂O₅) was 127．5 kg/hm², 96．0 kg/hm², 63．0 kg/hm² respectively, which may promote flue-cured tobacco to grow , reduce flue-cured tobacco cost of production, raise flue-cured tobacco output and mass , increase economic efficiency thereby. But, when the content of soil available phosphate was sufficient (42．43 mg/kg) , applying phosphate fertilizer was without obvious effect.5．The sense comments of upper tobacco leaf indicated that, the flue-cured tobacco which contained quantity of the phosphorus was 0．26±0．050%, the tobacco grade was higher (71．67) ; for 0．35±0．027% phosphorus content taking second place (69．44) ; and for 0．46±0．066% phosphorus content, scored 67．33．The result of middle tobacco leaf showed: when the total P content was 0．24±0．019%, the score was the highest (76．6) , the quality and the quantity of aroma were relatively suitable and there was less offensive odor, the cigarette gas was exquisite, sweet smooth feeling was good, and the characteristic of superior fume was obvious; when the total P content was 0．35±0．035%, attracted scores points lowly, scored 75．2．And the sense comments of lower tobacco leaf indicated that, the flue-cured tobacco which contained quantity of the phosphorus was 0．23±0．019%, comments attracted scores points high, scored 74．3, it had the characteristic of superior fume; the flue-cured tobacco which contained quantity of the phosphorus was 0．17±0．026%, comments attracted scores points was low, scored 73．5．By the result of appraising and analyzing representative upper, middle, lower part tobacco leaf, we might initially consider flue-cured tobacco leaf, the quantity of phosphorus was 0．23%-0．26% blades to be the high quality tobacco leaf.6．By analyzing 2,256 representative soil samples in Fujian tobacco planting area. The research considered that the content of soil available phosphate is 0．06-335．62 mg/kg, averaged 28．37 mg/kg in Fujian. The order of averaged soil available phosphate in three tobacco planting area is: Longyan (32．66 mg/kg) >Sanming (28．52 mg/kg) >Nanping (21．61 mg/kg) .Soil, the content of available phosphate is more than 35．00 mg/kg, respectively accounted for 35．43%, 25．86%, 14．75% in Longyan, Sanming and Nanping tobacco planting area. Soil, the content of available phosphate is between 21．00 mg/kg-35．00 mg/kg, respectively accounted for 31．42%, 37．91%, 28．89% in Longyan, Sanming and Nanping tobacco planting area. Soil, the content of available phosphate is in the 10．00 mg/kg-20．00 mg/kg, respectively accounted for 27．01%, 28．53%, 33．94% in Longyan, Sanming and Nanping tobacco planting area. Soil, the content of available phosphate is less than 10．00 mg/kg, respectively accounted for 6．15%, 7．70%, 22．42% in Longyan, Sanming and Nanping tobacco planting area. Every cigarette area should assign and apply phosphate fertilizer according to the content of soil available phosphate.