Compound liquid fertilizer for improving combustibility of cigar tobacco leaves as well as preparation method and application of compound liquid fertilizer

Abstract

The invention discloses a compound liquid fertilizer for improving combustibility of cigar tobacco leaves as well as a preparation method and application of the compound liquid fertilizer. The compound liquid fertilizer comprises the following components by concentration: 11-12 g / L of zinc, 1.3-1.6 g / L of boron, 0.6-0.8 g / L of molybdenum, 3-4 g / L of brown algae essence, 3-4 g / L of alfalfa extract paste and 78-83 g / L of sugar alcohol chelated magnesium (based on magnesium). The high-efficiency compound liquid fertilizer is constructed by taking sugar alcohol chelated magnesium as a core and compounding trace elements such as zinc, boron and molybdenum as well as the brown algae essence and the alfalfa extract, the magnesium element can be stably released, the interference of side-effect ions is avoided, meanwhile, the potassium-chlorine ratio of tobacco leaves, carbon and nitrogen metabolism and soil micro-ecology are synergistically regulated and controlled, and the yield of the tobacco leaves is increased. Combustion components and physical structures of the tobacco leaves are optimized from the source, and finally the combustion quality of the cigar tobacco leaves is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of cigar tobacco technology, and in particular to a compound liquid fertilizer for improving the combustibility of cigar tobacco, its preparation method, and its application. Background Technology

[0002] Cigars, as a purely natural tobacco product made entirely from tobacco leaves, differ significantly in appearance and structure from traditional tobacco products (flue-cured tobacco, Burley tobacco, etc.), leading consumers to have higher demands for their quality and "all-natural" production. During the consumption of tobacco products, the combustibility of the tobacco leaves plays a decisive role in the quality of the tobacco product. Studies have shown that insufficient combustibility of raw tobacco leaves results in incomplete release of potential aroma components, leading to a strong off-flavor, high irritation, and black ash in the tobacco product, severely affecting the industrial usability of the tobacco leaves.

[0003] Compared to methods that use liquid fertilizers to regulate the combustibility of tobacco leaves, the technique of controlling the content of mineral elements and chemical substances in tobacco leaves through fertilization during field production, thereby regulating the combustibility of tobacco leaves, is obviously more natural and safer. Magnesium (Mg) is one of the key medium-quantity elements affecting the combustibility of tobacco leaves. Magnesium can promote the accumulation of combustion-related substances such as potassium and sugars in tobacco leaves. During tobacco combustion, the white inorganic ash skeleton (MgO) formed by magnesium directly improves the ash color and fire-holding capacity of the tobacco. Currently, magnesium supplementation in tobacco fields is mainly achieved through the application of traditional magnesium fertilizers such as magnesium oxide, magnesium carbonate, and magnesium sulfate. However, magnesium oxide and magnesium carbonate can only provide magnesium ions relatively quickly after application in acidic soils. Although magnesium sulfate can provide magnesium ions quickly in different soil environments, it also provides a large amount of sulfur along with magnesium. Excessive sulfate has a negative effect on the combustibility of tobacco leaves, and the application of large amounts of sulfate can exacerbate the acidification of acidic soils. In addition, the supplementation of magnesium fertilizer alone can easily cause an imbalance in the ratio of "combustion-supporting components" (such as potassium salts and organic acids) and "flame-retardant components" (such as proteins and polyphenols) in tobacco leaves. Furthermore, excessive accumulation of magnesium in the leaves can combine with other elements to form fire-retardant salts, which can actually reduce the combustibility.

[0004] Therefore, there is an urgent need for a high-efficiency magnesium fertilizer that can quickly provide magnesium ions, has no risk of excessive sulfur accumulation, and can synergistically regulate the balance of chemical components related to tobacco combustion. Summary of the Invention

[0005] In view of this, this application provides a compound liquid fertilizer for improving the combustibility of cigar tobacco leaves, its preparation method and application, to solve the problem of how to improve the combustibility of cigar tobacco leaves.

[0006] To achieve the above technical objectives, this application adopts the following technical solution: In one aspect, this application provides a compound liquid fertilizer for improving the combustibility of cigar tobacco leaves, comprising the following components at the following concentrations: 78-83 g / L sugar alcohol chelated magnesium (calculated as magnesium), 11-12 g / L zinc, 1.3-1.6 g / L boron, 0.6-0.8 g / L molybdenum, 3-4 g / L brown algae extract, and 3-4 g / L alfalfa extract.

[0007] Preferably, the sugar alcohol chelated magnesium is derived from sugar alcohol magnesium fertilizer, the zinc from zinc sulfate, the boron from boric acid, and the molybdenum from ammonium molybdate or sodium molybdate.

[0008] Preferably, the sugar alcohol magnesium fertilizer has a magnesium content ≥80 g / L, a sugar alcohol content ≥90 g / L, and a density of 1.35-1.38.

[0009] Preferably, the ingredients contain the following concentrations: sugar alcohol chelated magnesium (calculated as magnesium) 80 g / L, zinc 11.5 g / L, boron 1.5 g / L, molybdenum 0.7 g / L, phycocyanin 3 g / L, and alfalfa extract 3 g / L.

[0010] Secondly, this application provides a method for preparing a compound liquid fertilizer, comprising the steps of: adding zinc sulfate, boric acid, ammonium molybdate or sodium molybdate, phycocyanin and alfalfa extract to a sugar alcohol magnesium fertilizer, and stirring continuously until completely dissolved.

[0011] Thirdly, this application provides a method for improving the combustion quality of cigar tobacco leaves, including applying and spraying compound liquid fertilizer during the tobacco bushing stage.

[0012] The preferred method of topdressing is as follows: during the seedling stage, apply 58-62 L / mu, diluted 14-16 times, and then apply by drilling holes 20-25 cm away from the main stem of the tobacco plant.

[0013] Preferably, the spraying method is to spray compound liquid fertilizer once after topping and once 7 days before the first harvest.

[0014] Preferably, the spraying concentration and dosage are as follows: dilute the compound liquid fertilizer to a concentration of 0.4%-0.5wt%, and spray 40-60 ml per plant.

[0015] Preferably, the application rate is 60 L / mu, the dilution ratio is 15 times, and the hole is made 22 cm away from the main stem of the tobacco plant.

[0016] Preferably, the compound liquid fertilizer is diluted to a concentration of 0.5 wt%.

[0017] The beneficial effects of this application are as follows: This application constructs a high-efficiency compound liquid fertilizer by using sugar alcohol chelated magnesium as the core and compounding it with trace elements such as zinc, boron, and molybdenum, as well as phycocyanin and alfalfa extract. It can stably release magnesium in various soils with different pH levels, avoid interference from side-effect ions, and optimize the combustion components and physical structure of tobacco leaves from the source by synergistically regulating the potassium-chloride ratio, carbon and nitrogen metabolism and soil microecology, ultimately significantly improving the combustion quality of cigar tobacco leaves. Attached Figure Description

[0018] Figure 1 The results show the effects of different treatments on the pyrolysis behavior of cigar tobacco leaves. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] This application provides a compound liquid fertilizer for improving the combustibility of cigar tobacco leaves, comprising the following components at the following concentrations: 78-83 g / L sugar alcohol chelated magnesium (calculated as magnesium), 11-12 g / L zinc, 1.3-1.6 g / L boron, 0.6-0.8 g / L molybdenum, 3-4 g / L brown algae extract, and 3-4 g / L alfalfa extract.

[0021] This application uses sugar alcohol chelated magnesium as the core active ingredient, which encapsulates and protects magnesium ions, enabling it to resist the fixation of aluminum and iron ions in acidic soils and to avoid combining with carbonate ions to form insoluble salts in neutral and calcareous soils. This ensures that magnesium element maintains high availability in soil environments with pH 4.5-8.0, solving the problems of traditional magnesium oxide and magnesium carbonate being only suitable for acidic soils, and magnesium sulfate being easily affected by soil pH and having sulfur side effects. This application eliminates raw materials containing harmful anions such as sulfate and chloride ions, and only uses chelating agents to construct a stable structure with magnesium ions. After being applied to the soil, it only releases magnesium elements in a targeted manner, avoiding the aggravation of acidification of acidic soil by large amounts of sulfate ions, or the formation of salts with other elements that are detrimental to combustion. At the same time, it prevents the deterioration of tobacco quality caused by the accumulation of side-effect ions (such as chloride ions). This application combines zinc, boron, and molybdenum trace elements with sugar alcohol chelated magnesium. On the one hand, it promotes the absorption of combustible potassium, adjusts the carbon-nitrogen ratio and potassium-magnesium ratio of tobacco leaves, and reduces the chlorine content, thereby optimizing the high proportion of "combustion-supporting components". On the other hand, it alleviates the element antagonism caused by single magnesium supplementation, avoids excessive magnesium from combining with polyphenols and proteins to form flame-retardant substances, and coordinates the physical structure and chemical composition related to tobacco combustion from the source to improve combustion performance. The sugar alcohol in this application not only acts as a carrier of magnesium ions, but also, when used in combination with phycocyanin and alfalfa extract, promotes soil microbial activity and improves soil aggregate structure.

[0022] In some embodiments, sugar alcohol chelated magnesium is derived from sugar alcohol magnesium fertilizer, zinc is derived from zinc sulfate, boron is derived from boric acid, and molybdenum is derived from ammonium molybdate or sodium molybdate.

[0023] In some embodiments, the sugar alcohol magnesium fertilizer contains ≥80 g / L of magnesium, ≥90 g / L of sugar alcohol, and has a density of 1.35-1.38.

[0024] In some embodiments, the ingredients include the following concentrations: sugar alcohol chelated magnesium (calculated as magnesium) 80 g / L, zinc 11.5 g / L, boron 1.5 g / L, molybdenum 0.7 g / L, phycocyanin 3 g / L, and alfalfa extract 3 g / L.

[0025] In this embodiment, when the above-mentioned content is in the specific formulation described above, the effect on improving the combustion quality of cigar tobacco is particularly significant.

[0026] This application provides a method for preparing a compound liquid fertilizer, comprising the steps of: adding zinc sulfate, boric acid, ammonium molybdate or sodium molybdate, phycocyanin and alfalfa extract to a sugar alcohol magnesium fertilizer, and stirring continuously until completely dissolved.

[0027] This application provides a method for improving the combustion quality of cigar tobacco leaves, including applying and spraying compound liquid fertilizer during the tobacco bushing stage.

[0028] In some embodiments, the topdressing method is as follows: during the seedling stage, apply 28-62 L / mu at a rate of 14-30 times diluted and then apply the solution by drilling holes 20-25 cm away from the main stem of the tobacco plant.

[0029] In some embodiments, the application rate during the seedling stage is 28-32 L / mu.

[0030] In some embodiments, the application rate during the seedling stage is 58-62 L / mu.

[0031] In some embodiments, the topdressing rate is 60 L / mu, the dilution ratio is 15 times, and the hole is made 22 cm away from the main stem of the tobacco plant.

[0032] In some embodiments, the spraying method is as follows: spray once after topping and once 7 days before the first harvest, specifically by diluting the compound liquid fertilizer to a concentration of 0.4%-0.5%, and spraying 40-60 ml per plant.

[0033] In some embodiments, the concentration of the compound liquid fertilizer spraying is 0.5%, and the spraying amount per plant is 50 ml.

[0034] This application adopts a combined topdressing and foliar spraying method to further match the demand for magnesium during the growth period of tobacco leaves (especially from the vigorous growth period to the maturity period). Topdressing the soil promotes the absorption and utilization of magnesium and other nutrients by the roots of tobacco plants through the biostimulating effects of sugar alcohols, alginic acid, and alfalfa extract. Foliar spraying further ensures uniform maturity of tobacco leaves. Alginic acid and alginic acid oligosaccharides in sugar alcohols and alginic acid, and amino acids, sugars, and flavonoids in alfalfa extract regulate the chemical composition of tobacco leaves, especially small molecule pyrolytic substances and other substances related to combustion, and coordinate their combustibility.

[0035] Source of raw materials Alfalfa extract: Fresh alfalfa foliage at the budding stage was collected, washed, and dried in an oven at 50-55℃ until the moisture content was ≤10%. The powder was then pulverized and passed through a 50-70 mesh sieve to obtain alfalfa powder. A 70% ethanol solution was added at a material-to-liquid ratio of 1:20-1:15, and the mixture was placed in an ultrasonic extractor. The power was set to 350W, the frequency to 25-40kHz, and the temperature to 50-55℃. Ultrasonic extraction was performed for 50-70 minutes with intermittent stirring (5 minutes of operation followed by a 2-minute break). The extract was centrifuged at 3000-5000 r / min for 8-10 minutes. The supernatant was collected and the ethanol was recovered using a rotary evaporator (55℃, 0.08MPa vacuum) to obtain a paste-like alfalfa extract.

[0036] The following specific embodiments further illustrate this solution.

[0037] Example 1 A compound liquid fertilizer for improving the combustibility of cigar tobacco leaves contains the following components at the following concentrations: zinc sulfate, boric acid, sodium molybdate, phycocyanin, and alfalfa extract are added to 60L of sugar alcohol magnesium fertilizer and stirred until completely dissolved to obtain the compound liquid fertilizer for improving the combustibility of cigar tobacco leaves. The concentrations of each component in the compound liquid fertilizer are as follows: sugar alcohol chelated magnesium (calculated as magnesium) 80 g / L, zinc 11.5 g / L, boron 1.5 g / L, molybdenum 0.7 g / L, phycocyanin 3 g / L, and alfalfa extract 3 g / L.

[0038] Comparative Example 1 A compound liquid fertilizer, otherwise identical to Example 1, except that it does not include zinc sulfate, boric acid, sodium molybdate, phycocyanin, and alfalfa extract.

[0039] Comparative Example 2 A compound liquid fertilizer, otherwise identical to Example 1, except that sugar alcohol chelated magnesium is replaced with magnesium sulfate.

[0040] Comparative Example 3 A compound liquid fertilizer, otherwise identical to Comparative Example 2, except that it does not include zinc sulfate, boric acid, sodium molybdate, alginic acid, and alfalfa extract.

[0041] Testing and Evaluation The specific steps for cultivating cigar tobacco using compound liquid fertilizers from different embodiments and comparative proportions are as follows: A field experiment was conducted in Xinghua Village, Xijiadian Town, Danjiangkou City, Shiyan City, Hubei Province (32°47′22″N, 111°10′58″E, altitude 215.2 m). The tested soil was yellow-brown soil with a pH of 6.8 and medium fertility. The tested variety was the eggplant core variety 'Chuxue 14'. The experiment consisted of 6 treatment groups (T1-T6), with each treatment replicated 3 times, arranged in a randomized block design. In addition to conventional NPK fertilizers, the liquid fertilizers of each example and the comparative example were applied as top dressing and / or sprayed. The CK group received only conventional NPK fertilizers.

[0042] The planting methods were divided into sprayed group and unsprayed group: Spraying group: During the seedling stage, apply fertilizer at a rate of 60 L / mu, diluted 15 times, and apply by drilling holes 22cm away from the main stem of the tobacco plant. Spray once after topping and once 7 days before the first harvest. Specifically, dilute the compound liquid fertilizer to a concentration of 0.5wt% and spray 50 ml per plant.

[0043] Unsprayed group: During the seedling stage, apply fertilizer at a rate of 60 L / acre, diluted 15 times, and then apply by drilling holes 22cm away from the main stem of the tobacco plant.

[0044] The application methods for different compound liquid fertilizers are shown in Table 1.

[0045] Table 1 Treatment methods for different fertilizers

[0046] Analysis and determination: (1) Statistical methods for tobacco leaf grades, yield, and output value: The yield and output value were calculated by grading the tobacco leaves of each treatment according to the Hubei Provincial Local Standard DB42 / T1549-2023, and the yield of tobacco leaves of each treatment (wrapper, binder, and filler) was statistically analyzed. The output value of tobacco leaves was calculated based on the Hubei Provincial Cigar Tobacco Leaf Purchase Price in 2024. The continuous flow analysis method was used to determine the reducing sugar content of tobacco leaves according to the standard YC / T 159—2019, the nicotine content according to the standard YC / T 468—2013, the potassium content according to the standard YC / T217—2007, and the chlorine content according to the standard YC / T162—2002.

[0047] Table 2. Yield, output value, and grade ratio of cigar tobacco leaves treated with different methods

[0048] Table 2 shows that treatment group T1 had the highest yield and output value, both higher than the control (CK). Its total yield of high-value eggplant wrappers and bindings was also higher than other treatments. Notably, treatment T3, which applied only sugar alcohol magnesium fertilizer, had higher yield and output value than treatments applying only magnesium sulfate (T6) and magnesium sulfate + trace elements + plant extracts (T5). Furthermore, treatments applying both topdressing and foliar spraying (T1, T4) had higher yield, output value, and the production of high-quality tobacco leaves than the topdressing-only treatment, indicating that the combined application of topdressing and foliar spraying was more effective in promoting yield and the production of high-quality tobacco leaves.

[0049] Table 3. Ratios of magnesium content and potassium and chlorine content in cigar tobacco leaves treated with different methods.

[0050] Note: Significance level (P<0.05) Compared with the control group (CK), the magnesium content of cigar tobacco leaves treated with different formulations was significantly increased, and the potassium-to-chlorine ratio, nicotine, and reducing sugar were all elevated.

[0051] (2) Regarding the analysis of the influence of cigar tobacco leaf combustibility: The middle leaves were selected, and the main veins of the leaves were removed as the test samples. The combustion characteristics of the tobacco leaves were analyzed using a thermogravimetric analyzer (TA) under the following conditions: air atmosphere, approximately 8 mg of sample that had passed through a 65-mesh sieve was weighed into a platinum crucible, the initial temperature was room temperature, and the temperature was increased to 940℃ at a rate of 20℃ / min. The curve of sample weight change with temperature was obtained, and the DTG curve of the sample was obtained by first differentiation. In this work, the combustion initiation temperature and burnout temperature of the tobacco leaves were determined by the TG-DTG joint definition method based on the combustion weight loss (TG) curve and the differential thermal gravity (DTG) curve of the combustion spectrum. The ignition index (Di), combustion stability index (Fi), and comprehensive combustion characteristic index were used to determine the combustion characteristics. This study evaluated the combustion performance of cigar tobacco leaves under different treatments. The ignition performance of the samples was positively correlated with Di. The value reflects the flammability and reactivity of the sample. Fi is mainly used to evaluate the combustion stability of the sample during combustion. The larger the diameter, the more stable the combustion. The higher the value, the better the overall combustion performance of the sample.

[0052] Ignition Index:

[0053] Combustion stability index:

[0054] Overall Combustion Characteristics Index:

[0055] Average combustion rate:

[0056] In equations (1), (2), (3), and (4), Maximum combustion rate (maximum weight loss rate), % / min; The average combustion rate is expressed as % / min. Corresponding combustion initiation temperature, ℃; The temperature corresponding to the maximum combustion rate, in °C; The burnout temperature is ℃. The heating rate is expressed in °C / min. For the sample temperature to reach the combustion initiation temperature The corresponding remaining mass fraction of the sample at that time, % To ensure the sample temperature reaches the burnout temperature The corresponding remaining mass fraction of the sample at that time.

[0057] (2) Investigate the effects of different treatments on the pyrolysis behavior of cigar tobacco leaves: The results of the effects of different treatments on the pyrolysis behavior of cigar tobacco leaves are as follows Figure 1 As shown.

[0058] As temperature rises, the pyrolysis process of cigar tobacco leaves can be divided into five weight loss stages ( Figure 1 The process involves several stages: Stage I (21℃~120℃) is the dehydration and drying stage; Stage II (120℃~400℃) corresponds to the thermal decomposition temperature range of low-boiling-point organic compounds (such as nicotine); Stage III (400℃~510℃) mainly involves the successive decomposition of high molecular weight components such as cellulose, and the resulting coke is rapidly combusted; Stage IV (510℃~930℃) in the early stage mainly involves the decomposition of the remaining coke and lignin after the combustion in the previous stage, until the remaining material is inorganic ash (mainly composed of MgO, K2O, CaO, etc.), and the quality remains stable.

[0059] The rapid pyrolysis combustion of cigar tobacco mainly occurs in stages II and III, and the specific parameters and mass loss results are shown in the table below.

[0060] Table 4. Pyrolysis parameters and mass loss of cigar tobacco leaves under different treatments in stages II and III.

[0061] The above results demonstrate that the Zn, B, molybdenum, and plant extracts (algae extract and alfalfa extract) in the water-soluble fertilizer of this invention can further promote the increase of low-molecular-weight, easily pyrolytic organic matter (such as nicotine) content in tobacco leaves, as well as the increase of magnesium content and potassium-chlorine ratio, thereby reducing the activation energy consumed in the pyrolysis stages II and III and promoting the combustion of tobacco leaves. Potassium in tobacco leaves has a promoting effect on combustion; adding potassium salts to the surface of tobacco leaves can improve their combustibility. Chlorine has a negative impact, but this invention increases the potassium-chlorine ratio of cigar tobacco leaves through fertilization techniques, meaning that while improving the combustibility of tobacco leaves, it perfectly aligns with the "all-natural" positioning of high-end cigars.

[0062] Table 5. Pyrolysis characteristic parameters of tobacco leaves under different treatments

[0063] (3) Determination of ash value of cigar tobacco leaves: Select uniform and dried cigar tobacco leaf samples, grind them and pass them through a 60-mesh sieve. Use the multi-hole base smoldering method to simulate the smoldering process of cigar tobacco. Operate in a fume hood, using an aluminum plate as a platform, and pile the tobacco powder into a cone or small mountain shape on the base. Lightly sweep the tip of the flame gun across the top of the powder pile. Patiently wait for the smoldering layer to spread completely from top to bottom until the entire powder pile turns into white / gray ash and there is no red heat. After it cools naturally, carefully collect the ash with a brush. Place the collected ash on A4 paper, press it firmly with a powder presser to make a round cake with a diameter of 2.0±0.2cm, and make its surface smooth and without cracks. Use an X-Rite Ci6X colorimeter to determine the red-green value a of the ash. (Positive values ​​represent the red direction, negative values ​​represent the green direction), Yellow / Blue value b (Positive values ​​represent the yellow direction, negative values ​​represent the blue direction), brightness value L (0 represents black, 100 represents white), chromaticity value ΔEab The color difference is calculated using the 1976 color difference formula, as follows.

[0064] ΔEab = + +

[0065] In the formula, △L It's the difference in brightness, △a , △b It is the color index difference, calculated using the following formula: ΔL =L1 -L0 , Δa =a1 -a0 Δb =b1 -b0 In the formula, L1 a1 b1 It is a measured value, L0 a0 b0 It is the standard value on the standard whiteboard (L0) =95.51, a0 =-0.81、b0 =1.52). ΔEab The larger the size, the darker the color; conversely, the smaller the size, the lighter the color.

[0066] Table 6 Ash values ​​of tobacco leaves under different treatments

[0067] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A complex liquid fertilizer for improving the combustibility of cigar tobacco leaves, characterized by, The composition comprises the following ingredients: zinc 11-12 g / L, boron 1.3-1.6 g / L, molybdenum 0.6-0.8 g / L, brown algae extract 3-4 g / L, alfalfa extract 3-4 g / L, and sugar alcohol chelated magnesium (as Mg) 78-83 g / L.

2. The complex liquid fertilizer for improving the combustibility of a cigar leaf according to claim 1, wherein, The sugar alcohol chelated magnesium is derived from a sugar alcohol magnesium fertilizer, the zinc is derived from zinc sulfate, the boron is derived from boric acid, and the molybdenum is derived from ammonium molybdate or sodium molybdate.

3. The complex liquid fertilizer for improving the combustibility of a cigar leaf according to claim 1, characterized by, The sugar alcohol magnesium fertilizer has a magnesium content of ≥80 g / L, a sugar alcohol content of ≥90 g / L, and a density of 1.35-1.

38.

4. The complex liquid fertilizer for improving the combustibility of a cigar leaf according to claim 1, characterized by, The composition comprises the following ingredients at the following concentrations: sugar alcohol chelated magnesium (as Mg) 80 g / L, zinc 11.5 g / L, boron 1.5 g / L, molybdenum 0.7 g / L, brown algae extract 3 g / L, and alfalfa extract 3 g / L.

5. A method of preparing a composite liquid fertilizer as claimed in any one of claims 1 to 4, characterised in that, The method comprises the steps of: adding zinc sulfate, boric acid, ammonium molybdate or sodium molybdate, brown algae extract, and alfalfa extract to a sugar alcohol magnesium fertilizer, and continuously stirring until all are dissolved.

6. A method of improving the burning quality of a cigar leaf, characterized in that, The method comprises the steps of: applying the compound liquid fertilizer as claimed in any one of claims 1-4 to tobacco plants during the rosette stage and spraying the compound liquid fertilizer to the tobacco plants.

7. The method of claim 6, wherein, The application method comprises the steps of: during the rosette stage, applying the compound liquid fertilizer at a dosage of 58-62 L / acre, diluting the compound liquid fertilizer 14-16 times, and then applying the diluted compound liquid fertilizer to the tobacco plants by punching holes at a distance of 20-25 cm from the main stem of the tobacco plants.

8. The method of claim 6, wherein, The spraying method comprises the steps of: after topping and 7 days before the first harvest, diluting the compound liquid fertilizer to a concentration of 0.4-0.5 wt%, and then spraying 40-60 ml of the diluted compound liquid fertilizer to each tobacco plant.

9. The method of claim 7, wherein, The application method comprises the steps of: applying the compound liquid fertilizer at a dosage of 60 L / acre, diluting the compound liquid fertilizer 15 times, and then applying the diluted compound liquid fertilizer to the tobacco plants by punching holes at a distance of 22 cm from the main stem of the tobacco plants.

10. The method of claim 8, wherein, The spraying method comprises the steps of: diluting the compound liquid fertilizer to a concentration of 0.5 wt%, and then spraying 50 ml of the diluted compound liquid fertilizer to each tobacco plant.

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