Tobacco root-promoting nutrient and use thereof

Abstract

The present application relates to a tobacco root-promoting nutrient agent and application thereof, and belongs to the technical field of flue-cured tobacco planting.The tobacco root-promoting nutrient agent comprises a basic nutrient solution, a biological stimulation agent and mineral nutrients; the basic nutrient solution further comprises a seedling-raising nutrient solution, a composite sugar alcohol and trace elements; wherein, in the tobacco root-promoting nutrient agent, the seedling-raising nutrient solution contains 18-22 g / L of nitrogen elements, 12-17 g / L of phosphorus elements and 12-17 g / L of potassium elements in terms of mass volume content; the content of the composite sugar alcohol is 1-1.5 g / L, the biological stimulation agent contains at least one of alginic acid and its derivatives, polyglutamic acid and brown algae oligosaccharide; and the mineral nutrients contain at least one of mineral source fulvic acid potassium, chelated zinc and ammonium phosphate.The tobacco root-promoting nutrient agent provided by the present application can provide balanced nutrition for flue-cured tobacco seedling raising, promote the early growth of flue-cured tobacco seedlings, and enhance the resistance of flue-cured tobacco seedlings.

Description

Technical Field

[0001] This invention belongs to the field of flue-cured tobacco planting technology, and relates to a tobacco root-promoting nutrient agent and its application. Background Technology

[0002] Floating seedling raising technology is currently the main method of flue-cured tobacco seedling raising in my country. However, due to the small size of the holes, the flue-cured tobacco seedlings have limited growth space, which is not conducive to cultivating strong seedlings. This can lead to problems such as poor uniformity of growth and poor stress resistance in the field after transplanting.

[0003] Early and rapid growth of tobacco seedlings is the core foundation for high-quality and high-yield flue-cured tobacco, requiring a balance between nutrient supply, root development, and stress resistance enhancement. Existing seedling nutrients are mostly based on nitrogen, phosphorus, and potassium, which only meet the basic growth needs of seedlings. In actual tobacco production, seedlings often experience slow or even stagnant growth after transplanting to the field.

[0004] As the industry raises its requirements for tobacco quality, the limitations of traditional formulas are becoming increasingly apparent: the supply of a single element leads to nutritional imbalances, which not only makes it difficult to promote robust root development and early growth, but also makes the tobacco seedlings weak in resistance to adverse conditions, making them susceptible to soil-borne diseases such as black shank and root rot. Furthermore, the seedlings recover slowly after transplanting, hindering the achievement of the goal of early growth and rapid development.

[0005] Therefore, developing a nutrient formula that can provide balanced nutrition, promote root development, enhance stress resistance, and promote early and rapid growth of tobacco seedlings, while taking into account nutrient supply, root cultivation, and stress resistance enhancement, is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a tobacco root-promoting nutrient agent and its application, which provides balanced nutrition for tobacco seedling growth, promotes root development, enhances stress resistance, and promotes early and rapid growth of tobacco seedlings.

[0007] To achieve the above objectives, the present invention adopts the following technical solution.

[0008] In a first aspect, the present invention provides a tobacco root-promoting nutrient agent, comprising a basic nutrient solution, a biostimulant preparation (or biostimulant or biostimulant) and mineral nutrients (or mineral nutrients). The basic nutrient solution includes seedling nutrient solution, compound sugar alcohol, and trace elements; wherein, in the tobacco root-promoting nutrient agent, the seedling nutrient solution contains, by mass and volume, 18-22 g / L of nitrogen, 12-17 g / L of phosphorus, and 12-17 g / L of potassium; the content of the compound sugar alcohol is 1-1.5 g / L. The biostimulant contains at least two of alginate and its derivatives, polyglutamic acid, and brown alginic oligosaccharides. The mineral nutrients include at least one of mineral-derived potassium humate, chelated zinc, and ammonium phosphate.

[0009] Preferably, the seedling nutrient solution contains 20 g / L of nitrogen, 15 g / L of phosphorus, and 15 g / L of potassium by mass and volume.

[0010] Optionally, the trace elements in the basic nutrient solution include at least one of boron, zinc, manganese, iron, copper, molybdenum, calcium, and magnesium.

[0011] In this invention, the mass-volume content of the complex sugar alcohol is 1~1.5 g / L (e.g., 1.1 g / L, 1.2 g / L, 1.25 g / L, 1.3 g / L or 1.4 g / L), preferably 1.2~1.3 g / L, and more preferably 1.25 g / L. The complex sugar alcohol is a mixture of various monosaccharide alcohols, possessing unique physicochemical properties and biological activities. It can significantly promote the absorption of nutrients by roots. After entering the plant, it can act as a signaling molecule, regulating the transport and distribution of nutrients, and improving the crop's resistance to harsh environments such as drought, salinity, and low temperature.

[0012] Preferably, the tobacco root-promoting nutrient agent contains, by mass and volume, the trace elements comprising: boron 0.8-1.2 g / L (e.g., 0.9 g / L, 1 g / L, or 1.1 g / L), zinc 0.35-0.4 g / L (e.g., 0.36 g / L, 0.37 g / L, 0.375 g / L, 0.38 g / L, or 0.39 g / L), manganese 0.2-0.4 g / L (e.g., 0.25 g / L, 0.35 g / L, or 0.35 g / L), iron 0.1-0.4 g / L (e.g., 0.11 g / L, 0.12 g / L, 0.125 g / L, or 0.13 g / L), and copper 0.23-0.27 g / L (e.g., 0.24 g / L, 0.25 g / L, or 0.26 g / L). The concentrations of molybdenum are 0.23–0.27 g / L (e.g., 0.24 g / L, 0.25 g / L, or 0.26 g / L), and the concentrations of calcium and magnesium are 0.8–1.2 g / L (e.g., 0.9 g / L, 1 g / L, or 1.1 g / L).

[0013] In this invention, trace elements (iron, boron, manganese, zinc, copper, molybdenum, etc.) are present in very small amounts in tobacco plants, but they are crucial for the morphology, physiological activity, nutrient absorption, and stress resistance of tobacco seedling roots. Appropriate supplementation of these elements can promote early and rapid root growth, root elongation, and an increase in lateral roots, and synergistically enhance the absorption of nitrogen nutrients by tobacco seedlings. In this invention, trace elements exist in active and / or chelated forms.

[0014] More preferably, the tobacco root-promoting nutrient agent contains, by mass and volume, 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium and magnesium.

[0015] Preferably, the alginic acid and its derivatives are seaweed extracts; more preferably, the total mass content of alginic acid and its derivatives in the seaweed extract is 30-40% (e.g., 35%).

[0016] More preferably, the content of alginic acid and its derivatives in the tobacco root-promoting nutrient agent is 70-150 g / L (e.g., 75 g / L, 80 g / L, 90 g / L, 100 g / L, 120 g / L or 140 g / L, by mass-volume content).

[0017] More preferably, the content of alginic acid and its derivatives in the tobacco root-promoting nutrient agent is 70-95 g / L (e.g., 75 g / L, 80 g / L, 85 g / L, 90 g / L or 95 g / L) by mass-volume content.

[0018] In the tobacco root-promoting nutrient agent provided by this invention, alginic acid (containing seaweed extract) is a natural biostimulant that can promote root cell division and elongation, and promote strong roots. Alginic acid and its derivatives are beneficial to the root development of tobacco seedlings, increasing root weight and root vitality, and also beneficial to increasing the aboveground weight of tobacco seedlings. However, alginic acid and its derivatives have little effect on the plant height of tobacco seedlings. Polyglutamic acid has the effects of strong water retention (forming a "root protective film"), effective chelation of nutrients, and direct stimulation of root development. Appropriate levels of polyglutamic acid are beneficial to increasing the plant height and root vitality of tobacco seedlings, but not to increasing the root weight and aboveground weight of tobacco seedlings. However, lower levels of polyglutamic acid have an adverse effect on the root vitality of tobacco seedlings. In addition, lower or higher levels of polyglutamic acid are not conducive to the cultivation of root length in tobacco seedlings. Fucoidan is an immune biostimulant that can induce endogenous hormones in the root system to explosively promote root growth and strengthen roots, and improve root resistance. Fucoidan is beneficial to the root development of tobacco seedlings, but not to the aboveground weight of tobacco seedlings. In addition, the high or low content of brown algae oligosaccharides has an uncertain impact on the plant height, root weight, and root activity of tobacco seedlings.

[0019] Combining the above-mentioned biostimulants can fully utilize their individual functions, resulting in a comprehensive effect that promotes root growth and enhances the root system's resistance to the drought and water shortage environment during the seedling stage of Yunnan tobacco.

[0020] Preferably, the biostimulant comprises or is composed of polyglutamic acid and fucoidan oligosaccharides.

[0021] Preferably, the polyglutamic acid content in the tobacco root-promoting nutrient is 50-150 g / L (e.g., 60 g / L, 80 g / L, 90 g / L, 100 g / L, 120 g / L, or 140 g / L, by weight / volume). More preferably, the polyglutamic acid content in the tobacco root-promoting nutrient is 90-95 g / L (e.g., 92 g / L, 93 g / L, 93.75 g / L, or 94 g / L, by weight / volume). Even more preferably, the polyglutamic acid content in the tobacco root-promoting nutrient is 93-94 g / L (e.g., 93.5 g / L, 93.75 g / L, or 94 g / L, by weight / volume). Even more preferably, the polyglutamic acid content in the tobacco root-promoting nutrient is 93.5-94 g / L (e.g., 93.75 g / L, by weight / volume).

[0022] Preferably, the content of the fucoidan oligosaccharide in the tobacco root-promoting nutrient agent is 70-80 g / L (e.g., 72 g / L, 74 g / L, 75 g / L, or 78 g / L, by mass / volume). More preferably, the content of the fucoidan oligosaccharide is 73-76 g / L (e.g., 74 g / L, 74.5 g / L, 75 g / L, or 75.5 g / L). Even more preferably, the content of the fucoidan oligosaccharide is 74.5-75.5 g / L (e.g., 75 g / L).

[0023] Preferably, the content of potassium humate from mineral sources in the tobacco root-promoting nutrient agent, by mass-volume percentage, is 35-170 g / L (e.g., 40 g / L, 60 g / L, 80 g / L, 100 g / L, 120 g / L, or 150 g / L); more preferably, the content of potassium humate from mineral sources is 120-170 g / L (e.g., 130 g / L, 140 g / L, 150 g / L, or 160 g / L). Even more preferably, the content of potassium humate from mineral sources is 140-160 g / L (e.g., 145 g / L, 150 g / L, or 155 g / L).

[0024] Preferably, the chelated zinc content in the tobacco root-promoting nutrient agent is 25-80 g / L (e.g., 30 g / L, 40 g / L, 50 g / L, 60 g / L or 70 g / L) by mass-volume content; more preferably, the chelated zinc content is 70-80 g / L (e.g., 72 g / L, 74 g / L, 75 g / L or 78 g / L).

[0025] Preferably, the content of ammonium phosphate in the tobacco root-promoting nutrient is 70-80 g / L (e.g., 72 g / L, 74 g / L, 75 g / L or 78 g / L) by mass-volume content.

[0026] In this invention, chelated zinc is beneficial for improving root length, root weight, and root activity in tobacco seedlings. However, its effects on other growth indicators of tobacco seedlings are limited by the concentration of chelated zinc, resulting in either beneficial or detrimental effects. Appropriate concentrations of ammonium phosphate have beneficial effects on plant height, root length, root weight, aboveground part weight, and root activity in tobacco seedlings, but lower concentrations have detrimental effects; therefore, the preferred ammonium phosphate content in this invention is 70-80 g / L. Potassium humate from mineral sources is a unique potassium-rich amino acid fertilizer that has beneficial effects on plant height, root weight, and aboveground part weight, but higher concentrations are detrimental to improving root length and root activity.

[0027] Preferably, the chelated zinc in the mineral nutrients includes EDTA chelated zinc.

[0028] Secondly, the present invention provides an application of any of the above-mentioned tobacco root-promoting nutrients in promoting early and rapid growth of tobacco seedlings during the growth of flue-cured tobacco.

[0029] Preferably, the tobacco root-promoting nutrient agent described above is diluted and sprayed onto the roots of tobacco seedlings (or tobacco plants).

[0030] This invention conducts hydroponic experiments on tobacco seedlings using different dosages of biostimulants and mineral nutrients, and monitors and evaluates the root-promoting effects on the seedlings. By measuring indicators such as plant height, root length, root weight, above-ground weight, and root vitality, the components of a highly effective tobacco root-promoting nutrient agent are screened, and these components are scientifically combined to form a nutrient solution formula that promotes early and rapid growth of tobacco seedlings, namely, the tobacco root-promoting nutrient agent. When applied to flue-cured tobacco production, this tobacco root-promoting nutrient agent provides seedlings with a balanced supply of nutrients, promotes root development, enhances stress resistance, and accelerates early and rapid growth.

[0031] This invention investigates the effects of different dosages of tobacco root-promoting nutrients on the growth of tobacco seedlings in hydroponic experiments, and determines the appropriate dosage of tobacco root-promoting nutrients for promoting early and rapid growth of tobacco seedlings when applied to flue-cured tobacco production.

[0032] The tobacco root-promoting nutrient agent provided by this invention is a nutrient agent formula that promotes early and rapid growth of tobacco seedlings. It can increase the height, root length, root weight and above-ground weight of tobacco seedlings, improve the root vitality of tobacco seedlings, and is convenient and quick to apply.

[0033] In this invention, the above-mentioned technical features can be freely combined to form new technical solutions, provided they do not conflict with each other.

[0034] The technical solution provided by this invention has the following beneficial technical effects compared with the prior art: (1) The tobacco root-promoting nutrient agent provided by the present invention provides nutrients for root growth by adding mineral nutrients and biostimulants, and promotes root cell division and elongation by using bioactivating substances, thereby simultaneously promoting the absorption of nutrients and rapid growth of tobacco seedling roots, achieving the goal of early growth and rapid development, and improving the resistance of roots to drought and water shortage stress. (2) The tobacco root-promoting nutrient agent provided by the present invention, by adding biostimulant and mineral nutrients to the basic nutrient solution, enables the three to work synergistically, comprehensively improving the indicators of plant height, root length, root weight, aboveground weight and root vitality of tobacco seedlings during the tobacco seedling raising period, significantly promoting the early growth and rapid development of tobacco seedlings, and providing a nutrient agent for tobacco production that can provide balanced nutrition, promote root development, enhance stress resistance and promote the early growth and rapid development of tobacco seedlings. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0037] All test materials and experimental raw materials mentioned in the following description are commercially available. The biostimulant raw materials were all sourced from Mengbaolong Biotechnology Co., Ltd., and then mixed according to the required mass-to-volume ratios in the experimental protocol.

[0038] Comparative Example 1 Using water as a root-promoting nutrient for tobacco, a hydroponic experiment was conducted to study its effect on promoting early and rapid growth of flue-cured tobacco seedlings. The specific steps are as follows.

[0039] Tobacco seedlings (or plants, using Yunyan 87) were placed in wide-mouthed triangular flasks. 500 mL of clean water was used as the base solution for this hydroponic experiment. Yunyan 87 was used as the test seedlings, which were placed directly in the water. Each seedling was treated with 500 mL of nutrient solution for 20 days. This treatment was repeated five times, and the average value was used to study the effect of clean water on promoting early and rapid growth of flue-cured tobacco seedlings.

[0040] Example 1 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Mineral nutrients: Contains 75g / L EDTA-chelated zinc (Mengbaolong Biotechnology Co., Ltd.), 75g / L ammonium phosphate, and 150g / L mineral-derived potassium humate. Among them, the mineral-derived potassium humate contains 50 wt% humic acid, 50 wt% fulvic acid, and 12 wt% potassium oxide.

[0041] The above-mentioned tobacco root-promoting nutrients were applied to the growth of flue-cured tobacco using a hydroponic experiment to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0042] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed well to obtain nutrient solution No. 2. 500 mL of this nutrient solution was used as the base solution for this hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in nutrient solution No. 2. That is, each seedling was treated with 500 mL of nutrient solution for hydroponic cultivation for 20 days. This hydroponic experiment was repeated 5 times, and the average value was used to study the effect of nutrient solution No. 2 on promoting early and rapid growth of flue-cured tobacco seedlings. The results are shown in Table 1.

[0043] Example 2 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant: Contains 75 g / L alginic acid, wherein the alginic acid is added using alginic acid extract stock solution (containing 35wt% alginic acid) as raw material; Mineral nutrients: Contains 75 g / L EDTA-chelated zinc, 75 g / L ammonium phosphate, and 150 g / L mineral-derived potassium humate. The potassium humate contains 50 wt% humic acid, 50 wt% fulvic acid, and 12 wt% potassium oxide.

[0044] The above-mentioned tobacco root-promoting nutrient agent (i.e., the combination of nutrient solution No. 2 and alginic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings through hydroponic experiments. The specific steps are as follows.

[0045] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution (i.e., 131 g of tobacco root-promoting nutrient solution) was placed in a spray container, and 15 L of water was added and mixed thoroughly to obtain the nutrient solution. The sprayer head was removed, and 500 mL of the nutrient solution was used as the base solution for this hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in the nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, and the cultivation time was 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 1.

[0046] Example 3 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant: Contains 93.75 g / L of polyglutamic acid; Mineral nutrients: Contains 75 g / L EDTA-chelated zinc, 75 g / L ammonium phosphate, and 150 g / L mineral-derived potassium humate. The potassium humate contains 50 wt% humic acid, 50 wt% fulvic acid, and 12 wt% potassium oxide.

[0047] The above-mentioned tobacco root-promoting nutrient agent (i.e., the combination of nutrient solution No. 2 and polyglutamic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings through hydroponic experiments. The specific steps are as follows.

[0048] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed thoroughly to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for a hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 1.

[0049] Example 4 A tobacco root-promoting nutrient agent, comprising the following ingredients: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant preparation: contains 75g / L of fucoidan oligosaccharide, wherein the fucoidan oligosaccharide is made from liquid fucoidan oligosaccharide; Mineral nutrients: Contains 75 g / L EDTA-chelated zinc, 75 g / L ammonium phosphate, and 150 g / L mineral-derived potassium humate. The potassium humate contains 50 wt% humic acid, 50 wt% fulvic acid, and 12 wt% potassium oxide.

[0050] The above-mentioned tobacco root-promoting nutrient agent (i.e., the combination of nutrient solution No. 2 and brown algae oligosaccharides) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0051] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed thoroughly to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 1.

[0052] Example 5 A tobacco root-promoting nutrient agent, comprising the following ingredients: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant preparation: contains 75 g / L alginic acid and 93.75 g / L polyglutamic acid, wherein the alginic acid is added using seaweed extract containing 35 wt% alginic acid and its derivatives as raw material; Mineral nutrients: Contains 75 g / L EDTA-chelated zinc, 75 g / L ammonium phosphate, and 150 g / L mineral-derived potassium humate. The potassium humate contains 50 wt% humic acid, 50 wt% fulvic acid, and 12 wt% potassium oxide.

[0053] The above-mentioned tobacco root-promoting nutrient solution (i.e., the combination of nutrient solution No. 2 with alginic acid and polyglutamic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0054] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed thoroughly to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for a hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 1.

[0055] Example 6 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant preparation: contains 93.75 g / L polyglutamic acid and 75 g / L fucoidan, wherein the fucoidan is made from fucoidan liquid; Mineral nutrients: Contains 75 g / L EDTA-chelated zinc, 75 g / L ammonium phosphate, and 150 g / L mineral-derived potassium humate. The potassium humate contains 50 wt% humic acid, 50 wt% fulvic acid, and 12 wt% potassium oxide.

[0056] The above-mentioned tobacco root-promoting nutrient solution (i.e., the combination of nutrient solution No. 2 with brown algae oligosaccharides and polyglutamic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0057] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed well to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 1.

[0058] Table 1. Growth status of tobacco seedlings under different hydroponic treatments Note: In the ANOVA using the multiple range method, lowercase letters represent statistical results at the P < 0.05 level. The same letter between treatments indicates no significant difference, while different letters represent the significance level of the difference between treatments.

[0059] As shown in Table 1, when nutrient solution No. 2 was combined with polyglutamic acid and fucoidan alone to form a tobacco root-promoting nutrient agent, both combinations improved various agronomic traits and root activity of tobacco seedlings, with similar effects. However, when nutrient solution No. 2 was combined with polyglutamic acid and fucoidan to form a tobacco root-promoting nutrient agent, its effect on improving various indicators of tobacco plants was more significant: compared with the water control (i.e., Comparative Example 1), plant height, root length, root weight, aboveground weight, and root activity increased by 17.8%, 33.6%, 21.9%, 55.4%, and 79.4%, respectively. In Example 6, the tobacco seedlings treated with the tobacco root-promoting nutrient agent formed by the combination of nutrient solution No. 2, fucoidan, and polyglutamic acid had the highest plant height, root length, root weight, aboveground weight, and root activity indicators in the above examples. Compared with the water control, the treatment in Example 6 significantly improved the aboveground weight and root activity of tobacco seedlings.

[0060] The following comparative studies investigated the screening of biostimulants and their interaction with mineral nutrient dosage. The effects of adding single biostimulants or mineral nutrients at different dilution ratios to a basic nutrient solution on the root-promoting nutrients for tobacco were studied to obtain the influence of different concentrations of single biostimulants or mineral nutrients on the early and rapid growth of tobacco seedlings. The tobacco seedlings used were Yunyan 87; the hydroponic experiment was conducted at the Agricultural Resources and Environment Teaching and Practice Base of the College of Resources, Hunan Agricultural University.

[0061] Comparative Example 2 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L complex sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium.

[0062] The above-mentioned tobacco root-promoting nutrients were applied to the growth of flue-cured tobacco using a hydroponic experiment to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0063] 200 mL of basic nutrient solution (as the stock solution) was dissolved in 15 L of water to obtain nutrient solution No. 1. 500 mL of nutrient solution No. 1 was used as the base solution for this hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in nutrient solution No. 1. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, and the cultivation time was 20 days. This hydroponic experiment was repeated 5 times, and the average value was used to study the effect of nutrient solution No. 1 on promoting early and rapid growth of flue-cured tobacco seedlings. The results are shown in Table 2.

[0064] Comparative Example 3 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant preparations: containing different concentrations of alginic acid, as shown in Table 2; among them, seaweed extract containing 35 wt% alginic acid and its derivatives was used as raw material and diluted by different ratios to obtain tobacco root-promoting nutrients containing different concentrations of alginic acid (i.e., biostimulant preparations).

[0065] The above-mentioned tobacco root-promoting nutrient agent (i.e., the combination of nutrient solution No. 1 and seaweed acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings through hydroponic experiments. The specific steps are as follows.

[0066] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed well to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 2.

[0067] Table 2. Growth status of tobacco seedlings treated with different concentrations of alginic acid root-promoting nutrients (20 days) Note: In the ANOVA using the multiple range method, lowercase letters represent statistical results at the P < 0.05 level. The same letter between treatments indicates no significant difference, while different letters represent the significance level of the difference between treatments.

[0068] Table 2 shows that the effect of adding alginic acid was not significant in terms of plant height. The treatment with an alginic acid content of 37.5 g / L showed the highest root length compared to other treatments. Compared with the control treatment in Comparative Example 2, except for the treatment with an alginic acid content of 50 g / L, the addition of alginic acid increased the root weight of tobacco plants to varying degrees. Among them, the treatment with an alginic acid content of 93.75 g / L had the heaviest root weight at 20 days of seedling growth, and the aboveground weight of the treatment with an alginic acid content of 93.75 g / L was significantly higher than that of other treatments. The treatments with alginic acid contents of 150 g / L, 93.75 g / L, and 75 g / L showed improved root activity compared to the control treatment. The root activity of the treatment with an alginic acid content of 75 g / L was significantly higher than that of other treatments, with a root activity value of 0.3032 μg / (g • h).

[0069] Comparative Example 4 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant preparations: containing different concentrations of polyglutamic acid, as shown in Table 3.

[0070] The above-mentioned tobacco root-promoting nutrient agent (i.e., the combination of nutrient solution No. 1 and polyglutamic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings through hydroponic experiments. The specific steps are as follows.

[0071] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed well to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 3.

[0072] Table 3. Growth status of tobacco seedlings treated with different concentrations of polyglutamic acid root-promoting nutrients (20 days) Note: In the ANOVA using the multiple range method, lowercase letters represent statistical results at the P < 0.05 level. The same letter between treatments indicates no significant difference, while different letters represent the significance level of the difference between treatments.

[0073] As shown in Table 3, the treatment with a polyglutamic acid content of 75 g / L showed the greatest increase in plant height compared to the control treatment in Comparative Example 2. Compared to the control treatment, the treatment with a polyglutamic acid content of 50 g / L showed the greatest increase in root length. Compared to the control treatment, the treatments with polyglutamic acid contents of 150 g / L, 93.75 g / L, and 50 g / L all showed improved root activity. Among them, the root activity of the treatment with a polyglutamic acid content of 93.75 g / L was significantly higher than that of the other treatments, with a root activity value of 0.1592 μg / (g • h).

[0074] Comparative Example 5 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Biostimulant preparations: containing different concentrations of brown algae oligosaccharides.

[0075] The above-mentioned tobacco root-promoting nutrient agent (i.e., the combination of nutrient solution No. 1 and seaweed acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings through hydroponic experiments. The specific steps are as follows.

[0076] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed well to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 4.

[0077] Table 4. Growth status of tobacco seedlings treated with root-promoting nutrients containing different concentrations of brown algae oligosaccharides (20 days) Note: In the ANOVA using the multiple range method, lowercase letters represent statistical results at the P < 0.05 level. The same letter between treatments indicates no significant difference, while different letters represent the significance level of the difference between treatments.

[0078] As shown in Table 4, compared with Comparative Example 2, the addition of fucoidan increased the root length of tobacco plants to varying degrees. The root activity of the treatment with a fucoidan content of 75 g / L was significantly improved compared with the control treatment, with a root activity value of 0.1438 μg / (g • h).

[0079] Comparative Example 6 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Mineral nutrients: Contains EDTA-chelated zinc at varying concentrations.

[0080] The above-mentioned tobacco root-promoting nutrient solution (i.e., the combination of nutrient solution No. 2 with brown algae oligosaccharides and polyglutamic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0081] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed well to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 5.

[0082] Table 5. Growth status of tobacco seedlings treated with root-promoting nutrient agents containing different concentrations of mineral nutrients (20 days) Note: In the ANOVA using the multiple range method, lowercase letters represent statistical results at the P < 0.05 level. The same letter between treatments indicates no significant difference, while different letters represent the significance level of the difference between treatments.

[0083] Comparative Example 7 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Mineral nutrients: Contains ammonium phosphate at different concentrations.

[0084] The above-mentioned tobacco root-promoting nutrient solution (i.e., the combination of nutrient solution No. 2 with brown algae oligosaccharides and polyglutamic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0085] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed thoroughly to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 6.

[0086] Table 6. Growth status of tobacco seedlings treated with root-promoting nutrient agents containing different concentrations of mineral nutrients (20 days) Note: In the ANOVA using the multiple range method, lowercase letters represent statistical results at the P < 0.05 level. The same letter between treatments indicates no significant difference, while different letters represent the significance level of the difference between treatments.

[0087] Comparative Example 8 A tobacco root-promoting nutrient agent, comprising the following components: Basic nutrient solution: contains 20 g / L nitrogen, 15 g / L phosphorus, 15 g / L potassium, and 1.25 g / L compound sugar alcohol, and trace elements: contains 1 g / L boron, 0.375 g / L zinc, 0.3 g / L manganese, 0.125 g / L iron, 0.25 g / L copper, 0.25 g / L molybdenum, and 1 g / L calcium + magnesium. Mineral nutrients: Contains potassium humate of varying concentrations. Specifically, the potassium humate contains 50 wt% humic acid, 50 wt% fulvic acid, and 12 wt% potassium oxide.

[0088] The above-mentioned tobacco root-promoting nutrient solution (i.e., the combination of nutrient solution No. 2 with brown algae oligosaccharides and polyglutamic acid) was applied to the growth of flue-cured tobacco to promote early and rapid growth of tobacco seedlings. The specific steps are as follows.

[0089] Using the aforementioned tobacco root-promoting nutrient solution as the stock solution, 200 mL of the stock solution was dissolved in 15 L of water and mixed well to obtain the nutrient solution. 500 mL of this nutrient solution was used as the base solution for the hydroponic experiment. Yunyan 87 tobacco seedlings were used as the test seedlings, and the seedlings were placed in this nutrient solution. That is, each seedling was treated with 500 mL of nutrient solution for the hydroponic experiment, with a cultivation time of 20 days. This hydroponic experiment was repeated 5 times. The results are shown in Table 7.

[0090] Table 7. Growth status of tobacco seedlings treated with root-promoting nutrient agents containing different concentrations of mineral nutrients (20 days) Note: In the ANOVA using the multiple range method, lowercase letters represent statistical results at the P < 0.05 level. The same letter between treatments indicates no significant difference, while different letters represent the significance level of the difference between treatments.

[0091] As shown in Table 5, the root length of the treatments with added chelated zinc was increased to varying degrees compared with the control treatment in Comparative Example 2, with the treatment with a chelated zinc content of 75 g / L showing the greatest increase. Furthermore, the treatment with a chelated zinc content of 75 g / L significantly increased the plant height compared with other treatments, and also showed the best improvement in root weight and aboveground weight. In addition, the root activity of the tobacco plants under the chelated zinc content of 75 g / L was significantly higher than that under other treatments, with a root activity value of 0.2099 μg / (g•h).

[0092] As shown in Table 6, the treatment with ammonium phosphate content of 75 g / L showed the best results in terms of plant height, root length, root weight, aboveground weight, and root activity compared to other concentrations. It significantly increased the plant height and aboveground weight of tobacco plants, and its root activity value was 0.2863 μg / (g • h).

[0093] As shown in Table 7, compared with the control treatment in Comparative Example 2, the addition of potassium humate from mineral sources increased the height of tobacco plants to varying degrees. The treatment with a potassium humate content of 37.5 g / L showed the highest root length compared with other treatments. Compared with the control treatment, the treatments with potassium humate from mineral sources increased the root weight of tobacco plants to varying degrees. The aboveground weight of the treatment with a potassium humate content of 150 g / L was significantly higher than that of the control treatment and other potassium humate treatments. Among them, the root activity of tobacco plants under the treatment with a potassium humate content of 150 g / L was significantly higher than that of other treatments, with a root activity value of 0.9302 μg / (g • h).

[0094] Field trial on the effects of tobacco root-promoting nutrient application on the early growth of tobacco plants (1) Test site: Technology extension station of Daheqiao Village, Rende Subdistrict Office, Xundian County, Kunming City, Yunnan Province.

[0095] (2) Test materials (as shown in Table 8): Table 8: (3) Field trial design A field plot experiment was conducted. Considering the characteristics of batch harvesting and curing of tobacco leaves, a tagging method was used. The field experiment consisted of two treatments (CK and YX treatments) with three replicates. Each replicate plot had 30 plants. The treatment settings are shown in Table 9.

[0096] Table 9. Field trial treatments showing the effects of tobacco root-promoting nutrient application on early growth of tobacco plants. Fertilizer application methods: CK: The tobacco planting and management model of local farmers in the Kunming tobacco-growing area, which involves ensuring normal fertilization (ensuring a basic amount of fertilizer for the tobacco seedlings) and routine field management. YX: During the seedling stage after transplanting, apply tobacco root-promoting nutrient solution by root irrigation. Take 200 mL of tobacco root-promoting nutrient solution as a stock solution, pour it into a 15-liter container, add water and mix thoroughly. Take 500 mL and pour it directly around the roots of the tobacco plants to thoroughly irrigate them. Other management is the same as the farmers' usual planting mode (i.e., CK mode).

[0097] Field management: (1) Two treatments, three replicates, and a total of six plots. Five tobacco seedlings with similar growth conditions were selected from each plot and tagged. The agronomic traits of the five tagged tobacco seedlings, namely plant height, leaf length and leaf width, were recorded on the 20th and 60th days after the application of nutrients.

[0098] (2) On the 20th and 60th days, three tobacco seedlings were randomly dug up from each plot (excluding the five seedlings with tags), keeping the roots intact, and marked with treatment numbers. They were then sent back to the laboratory for relevant index measurement and analysis. The measurement results are shown in Tables 10 and 11.

[0099] Table 10 Record of agronomic traits of tobacco plants in the field Note: Five tobacco seedlings in each plot are tagged and recorded for plant height, maximum leaf length, and maximum leaf width during the clustering stage and vigorous growth stage, and the average value is taken.

[0100] As shown in Table 10, the treatment with tobacco root-promoting nutrient (YX) showed varying degrees of improvement in plant height, maximum leaf length, and maximum leaf width on day 20 compared to the treatment with normal fertilization (CK). The plant height, maximum leaf length, and maximum leaf width increased by 1.5 cm, 0.9 cm, and 0.8 cm, respectively. On day 60, the plant height and maximum leaf length under the YX treatment increased by 0.4 cm and 0.1 cm, respectively, compared to the CK treatment.

[0101] Table 11 Effects of applying tobacco root-promoting nutrients on the early growth of tobacco seedlings Note: Units for each indicator: root length - cm; root weight - g; aboveground part weight - g; root activity - [μg / (g·h)]; CK: farmer's usual normal fertilization treatment; YX: early growth and rapid development nutrient treatment.

[0102] As shown in Table 11, on the 20th day after the application of the tobacco root-promoting nutrient, the root length, root weight, aboveground weight, root-to-shoot ratio, and root activity of the YX treatment were all increased to varying degrees compared with the CK treatment, increasing by 0.7 cm, 2.9 g, 23.6 g, 0.002, and 0.17 [μg / (g·h)], respectively; on the 60th day, the root length, root weight, aboveground weight, and root activity of the YX treatment increased by 1.3 cm, 4.8 g, 86.3 g, and 0.12 [μg / (g·h)], respectively, compared with the CK treatment.

[0103] The above descriptions are merely some preferred embodiments of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A tobacco root-promoting nutrient agent, characterized in that, The tobacco root-promoting nutrient solution includes a basic nutrient solution, a biostimulant, and mineral nutrients. The basic nutrient solution also includes seedling nutrient solution, compound sugar alcohol, and trace elements; wherein, in the tobacco root-promoting nutrient agent, the seedling nutrient solution contains, by mass and volume, 18-22 g / L of nitrogen, 12-17 g / L of phosphorus, and 12-17 g / L of potassium; the content of the compound sugar alcohol is 1-1.5 g / L. The biostimulant contains at least one of alginate and its derivatives, polyglutamic acid, and brown alginic acid. The mineral nutrients include at least one of mineral-derived potassium humate, chelated zinc, and ammonium phosphate.

2. The tobacco root-promoting nutrient agent according to claim 1, characterized in that, The seedling nutrient solution contains, by weight and volume, 20 g / L nitrogen, 15 g / L phosphorus, and 15 g / L potassium; and / or The mass-volume content of the compound sugar alcohol is 1.2~1.3 g / L.

3. The tobacco root-promoting nutrient agent according to claim 1, characterized in that, The trace elements include at least one of boron, zinc, manganese, iron, copper, molybdenum, calcium, and magnesium; The tobacco root-promoting nutrient agent contains, by mass and volume, 0.8-1.2 g / L boron, 0.35-0.4 g / L zinc, 0.2-0.4 g / L manganese, 0.1-0.4 g / L iron, 0.23-0.27 g / L copper, 0.23-0.27 g / L molybdenum, and 0.8-1.2 g / L calcium and magnesium.

4. The tobacco root-promoting nutrient agent according to claim 1, characterized in that, The alginic acid and its derivatives are derived from seaweed extracts, and the total mass content of alginic acid and its derivatives in the seaweed extracts is 30-40%. In the tobacco root-promoting nutrient agent, the content of alginic acid and its derivatives is 70~150g / L by mass and volume.

5. The tobacco root-promoting nutrient agent according to any one of claims 1-4, characterized in that, The biostimulant contains polyglutamic acid and fucoidan oligosaccharides; wherein... In the tobacco root-promoting nutrient agent, the content of polyglutamic acid is 50-150 g / L and the content of fucoidan is 70-80 g / L, based on mass and volume.

6. The tobacco root-promoting nutrient agent according to claim 5, characterized in that, In the tobacco root-promoting nutrient agent, the content of polyglutamic acid is 90-95 g / L and the content of fucoidan is 70-80 g / L, based on mass and volume.

7. The tobacco root-promoting nutrient agent according to any one of claims 1-4, characterized in that, In the tobacco root-promoting nutrient agent, the content of the mineral-derived potassium humate is 35~170 g / L, the content of the chelated zinc is 25~80 g / L, and the content of the ammonium phosphate is 70~80 g / L, based on mass and volume content. Preferably, in the tobacco root-promoting nutrient agent, the content of the mineral-derived potassium humate is 120-170 g / L, the content of the chelated zinc is 70-80 g / L, and the content of the ammonium phosphate is 70-80 g / L, based on mass and volume content.

8. The tobacco root-promoting nutrient agent according to claim 7, characterized in that, The mineral nutrients include chelated zinc, which includes EDTA chelated zinc.

9. The application of a tobacco root-promoting nutrient agent according to any one of claims 1-8 in promoting early and rapid growth of tobacco seedlings during the growth of flue-cured tobacco.

10. The application of the tobacco root-promoting nutrient agent according to claim 9 in promoting early and rapid growth of tobacco seedlings during flue-cured tobacco growth, characterized in that, After diluting the tobacco root-promoting nutrient, spray it onto the roots of the tobacco seedlings.

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