Effects Of Different Magnesium Fertilizer Types On Soil Magnesium Content,Yield And Quality Of Flue-cured Tobacco

In order tochangethe situation of soil magnesium deficiency and improve yield and quality of flue-cured tobacco,and then select the suitable magnesium type for Meizhou tobacco production region,this experiment used magnesium sulfate,magnesium oxide,magnesium hydroxide,calcium magnesium phosphate magnesium fertilizer types as treatments,and magnesium free as control,exploredeffects of different magnesium fertilizer on soil physical and chemical properties,agronomic traits,matter accumulatio n,chemical components,appearance quality and sensory quality,economic characters,yield and quality of flue-cured tobacco.The results showed that:1.The soil pH of all magnesium fertilizer before transplanting was higher than that of CK,while the soil p H after harvest was the opposite,which was lower than that of CK,soil p H was increased compared with that before transplanting.The content of available phosphorus and available potassium in soil decreased significantly after harvest,and soil available potassium in MgSO₄ treatment was the highest,reached 158.12mg/kg,which was significantly higher than that of other four treatments.During the whole field production,the Mg content of all treatments decreased and the overall trend was similar,but the content of Mg in eac h treatment was significantly higher than that of CK.2.The agronomic characters of flue-cured tobacco in different periods after applying magnesium fertilizer were higher than those of CK.In each field growth period,plant height of MgO treatment was the highest,respectively up to 80cm,103.33cm and 107.33cm,with the growth of tobacco plants in the field,the overall trend of plant height,stem girth,effective leaf number,leaf length,leaf width and pitch were increased.The effects of different treatments on the agronomic traits were different,but on the whole,all treatments improved the growth and development of tobacco plant.3.The accumulation of dry matter in different parts of tobacco plants showed an upward trend during the whole growth period.The ascent rate of 35-75d was the fastest after transplanting,and the dry matter accumulation reached the maximum value and then stabilized at 90d after transplanting.The dry matter accumulation of tobacco plants treated with magnesium fertilizer was higher than that of CK,the root dry matter accumulation was highest in MgO treatment,there were differences in leaf dry matter accumulation in different periods,MgO treatment was the largest at60d,but MgSO₄ treatment was the highest at 90d.The whole plant drymatter accumulation of MgSO₄ treatment was highest and up to 224.2g/strain.The contents of Mg in roots,stems and leaves of tobacco plants with different magnesium fertilizer treatments were higher than those in control,and all of them decreased w ith the development of growth stage.4.The application of magnesium fertilizer improved the appearance quality and sensory quality of Flue-cured tobacco,and the type of magnesium fertilizer was very important.Effects of different magnesium fertilizer trea tments on the appearance quality and sensory evaluation of tobacco leaves were different.The sensory quality of flue-cured tobacco leaves treated with MgSO₄ was the best,followed by MgO and Mg（OH）₂,and effect of calcium magnesium phosphate treatment on t he sensory quality of flue-cured tobacco leaves was less.5.The contents of total sugar,reducing sugar and starch in the upper leaves of flue-cured tobacco were higher than those in the control,while the content of total nitrogen and nicotine showed no difference with the CK,the potassium content was lower than that of the CK.The total sugar and nicotine content of MgO treatment was the highest,and the content of reducing sugar and starch in MgSO ₄ treatment was the highest.The content of reducing sugar in the middle leaves of MgO treated with magnesium fertilizer was the highest,the total sugar and starch content of MgSO ₄treatment was the highest,the content of nicotine content was the highest of Mg（OH）₂ treatment.From the lower leaves,the total suga r,reducing sugar and nicotine content of Mg（OH）₂ were the highest,which reached 22.66%,20.13%and2.17%respectively,and the highest content of starch was MgSO ₄ treatment（2.76%）.6.The yield and output value of MgSO₄ treatment were highest and respectively higher 21.52%and 36.29%than that of CK.The average price and ratio of high and middle flue-cured tobacco of MgO treatment were the highest.The ratio of upperleaves of Mg（OH）₂ treatment and the ratio of middle leavesof MgSO₄treatment were the highest.