Effects Of Two New Potassium Fertilizers On Potassium Transport In Soil-Flue-cured Tobacco In Southern Main Tobacco-growing Areas

Potassium is the important nutrient and quality element of tobacco,potassium content is one of the important index of tobacco quality evaluation.Applying potassium fertilizer can promote the growth metabolism of flue-cured tobacco,affect the quality and the smoking quality of tobacco,improve the luster,combustibility and capability of keep fire of tobacco leaf and hold fire and conducive to the accumulation of sugar and formation of tobacco aroma of tobacco leaf.The tobacco leaf potassium content is below 2%in our country,potassium levels cann,t meet the high quality tobacco leaves in most of the tobacco growing area.Low potassium content of tobacco is one of the important factors that limit the leaf quality of high quality tobacco in our country.The main factors which create the low potassium content of tobacco leaf in our country are:the rapid available potassium fertilizer used such as potassium sulphate and potassium nitrate are easy leached in soil;the soil potassium fixation is severe,the potassium applied into the soil meet the soil potassium fixation first then supply the growth of flue-cured tobacco;the intensity of potassium providing of soil cann,t match the law of potassium requirement of tobacco growth;the accumulation and distribution of potassium in tobacco are unreasonable,most of the potassium accumulate and distribute in root,stem and lower tobacco leaves after the maturity of tobacco.This paper took K326 as material,studied the rule and influence factor of potassium release,potassium fixation and potassium leaching of citrate soluble potassium fertilizer and humate potassium fertilizer,researched the influence of combined application of new potassium fertilizers and potassium sulfate on growth and accumulation and distribution of potassium of tobacco using pot experiment,verified the influence of combined application of new potassium fertilizer and potassium sulfate on growth and accumulation and distribution of potassium of tobacco in different soil types in the tobacco growing area of fen-flavor and luzhou-flavor by field experiment.This research selected the citrate soluble potassium fertilizer and humate potassium fertilizer which had better potassium release effect then applied to yellow soil and paddy soil in main tobacco areas in south to increase the content of potassium of tobacco and utilization rate of potassium.The specific research results of this paper were as follows:?1?Studied some physical and chemical properties of citrate soluble potassium fertilizer and humate potassium fertilizer,then researched the potassium leaching property in soil of new potassium fertilizers.The results showed that,the Ph of citrate soluble potassium fertilizer and humate potassium fertilizer were 11.16 and 10.15 respectively presented strong alkali which was beneficial to the improvement of acid soil;the solubility of new potassium fertilizer was lower in water?the citrate soluble potassium fertilizer was slightly soluble?,the solubility in citric acid liquor were 6.45 g/L and 14.96 g/L respectively which had guaranteed the potassium liberation in acid soil.The potassium leaching property showed potassium sulfate>citrate soluble potassium fertilizer>humate potassium fertilizer.Accumulated amount of leaching of K⁺and apparent leaching rate of citrate soluble potassium fertilizer were lower in yellow soil,they were also lower for humate potassium fertilizer in paddy soil.New potassium fertilizers could reduce the leaching amount of calcium in soil and were helpful to prevent the soil harden.The determinants of accumulated amount of leaching of K⁺of potassium fertilizer were total potassium content and slowly available potassium content of soil.The determinant of apparent leaching rate of potassium fertilizer was slowly available potassium content of soil.The higher slowly available potassium content,the higher risk of potash fertilizer leaching.?2?Researched the influence of low molecular organic acids and cationics on potassium liberation of new potassium fertilizers.The results showed that,the low molecular organic acids such as oxalic acid,tartaric acid and citric acid and cationics such as Ca²⁺,NH₄⁺and Na⁺could improve the potassium liberation of citrate soluble potassium fertilizer and humate potassium fertilizer.The effect of extracting agents on potassium liberation of citrate soluble potassium fertilizer showed oxalic acid>citric acid>tartaric acid>Ca2⁺>NH4⁺>Na⁺,Theeffectshowedoxalicacid>citricacid>tartaric acid>NH4⁺>Ca2⁺>Na⁺for humate potassium fertilizer.With the concentration improvement of low molecular organic acids and cation,the potassium liberation amount of citrate soluble potassium fertilizer and humate potassium fertilizer significant increased,and the citrate soluble potassium fertilizer had higher potassium liberation amount.?3?Studied the potassium fixation of new potassium fertilizers in different soil types.The results showed that,yellow soil and paddy soil had potassium fixation effect on potassium sulfate and new potassium fertilizers,the power of potassium fixation of soil showed potassium sulfate>citrate soluble potassium fertilizer>humate potassium fertilizer and the yellow soli was lower than paddy soil.The potassium fixation showed positive correlation with time and alternation of drying and wetting.The yellow soil had higher fixation ability than paddy soil with alternation of drying and wetting.Soil temperature could reduce the soil potassium fixation,but the effect was lower than moisture.?4?Researched the influence of combined application of new potassium fertilizers and potassium sulfate on growth and accumulation and distribution of potassium of tobacco using pot experiment.The results showed that,the combined application of new potassium fertilizers and potassium sulfate could promote the growth of flue-cured tobacco and increase dry matter accumulation of tobacco plant,the combined application of slow efficiency fertilizer and potassium sulfate had better effect than single application of them under the same amount of potassium nutrient inputs.The combined application of citrate soluble potassium fertilizer and potassium sulfate had better effect in yellow soil,the combined application of humate potassium fertilizer and potassium sulfate had better effect in paddy soil and the ratio of combined application was 25%potassium sulfate.This combined application could improve the potassium content of tobacco leaves of different parts and the best ratio of combined application for citrate soluble potassium fertilizer and humate potassium fertilizer was 50%-75%.The combined application of new potassium fertilizers and potassium sulfate could increase potassium content of economic area,facilitate potassium transfer from root,stem to leaf,promote the potassium accumulation.?5?Studied the influence of combined application of new potassium fertilizers and potassium sulfate on growth and leaf quality of tobacco by field experiment.The results showed that,the combined application of new potassium fertilizers and potassium sulfate could promote the growth of flue-cured tobacco and increase dry matter accumulation,facilitate the potassium distribution in plant and potassium accumulation in leaves,coordinate the chemical composition proportion of cured tobacco leaves,promote the improvement of quality of upper leaves,the increase of average price and the production value of tobacco leaves.25%citrate soluble potassium fertilizer with 75%potassium sulfate had the best effect in yellow soil,25%humate potassium fertilizer with 75%potassium sulfate had the best effect in paddy soil,the growth of tobacco in Hunan tobacco area was better than in Yunnan.For the effect on dry matter accumulation of root,the combined application of 50%citrate soluble potassium fertilizer and 50%potassium sulfate was the best in yellow soil and 50%humate potassium with 50%potassium sulfate was the best in paddy soil.The combined application of new potassium fertilizers and potassium sulfate could promote the distribution of potassium in leaves and stem,for the effect on potassium accumulation,the combined application of 50%citrate soluble potassium fertilizer and 50%potassium sulfate was the best in yellow soil and 50%humate potassium fertilizer with 50%potassium sulfate was the best in paddy soil in different tobacco growing area.Generally speaking,tobacco in Hunan tobacco area had higher potassium accumulation content and more coherent chemical composition in the same soil type.