Active nano fulvic acid and preparation method thereof, and development and application of biological fertilizer

Abstract

The invention provides active nano fulvic acid, a preparation method and development and application of a biological fertilizer, and belongs to the technical field of crop fertilizers. The active nano fulvic acid is prepared from weathered coal through ethanol extraction, concentrated sulfuric acid oxidation, nanoscale grinding and ultrasonic treatment, has higher biological activity and can improve the absorption and utilization efficiency of plants. Besides, the active nano fulvic acid can be combined with a synergist to prepare an active nano fulvic acid bio-fertilizer, the active nano fulvic acid bio-fertilizer is applied as a base fertilizer, and compared with a traditional bio-fertilizer, the active nano fulvic acid bio-fertilizer can significantly promote seed germination, promote crop growth, improve the soil environment and improve the crop yield and quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of crop fertilizers, and particularly relates to an active nano fulvic acid, a preparation method thereof, and the development and application of a biological fertilizer. Background Art

[0002] In the technical field of crop fertilizers, traditional biological fertilizers have certain limitations in promoting crop growth, improving fertilizer utilization efficiency, and improving the soil environment. With the development of agricultural modernization, the demand for fertilizers that are efficient, environmentally friendly, and can significantly increase crop yield and quality is increasing day by day.

[0003] Most commercially available ordinary fulvic acid fertilizers adopt simple extraction processes and are not finely processed. Such fertilizers have low biological activity, and the absorption and utilization efficiency of plant nutrients is not high, and they have poor effects in promoting seed germination and crop growth. In terms of improving the soil environment, traditional fertilizers cannot effectively improve the activity of enzymes in the soil, are difficult to promote the decomposition of organic matter in the soil and the release of nutrients, and cannot continuously provide sufficient nutrients for crop growth. At the same time, long-term application of traditional fertilizers may also lead to problems such as nutrient imbalance, soil compaction, and decline in cultivated land quality.

[0004] Moreover, existing fertilizers often lack reasonable formulations and cannot fully meet the nutritional requirements of crops at different growth stages. Therefore, it is urgent to develop a new type of biological fertilizer that can overcome the above defects, has high biological activity, high absorption and utilization rate, and can effectively promote crop growth, improve the soil environment, and increase crop yield and quality. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an active nano fulvic acid, a preparation method thereof, and an active nano fulvic acid biological fertilizer, which can significantly promote seed germination, promote crop growth, improve the soil environment, and increase crop yield and quality.

[0006] To achieve the above invention purpose, the present invention provides the following technical solutions:

[0007] A preparation method of an active nano fulvic acid, comprising the following steps: washing weathered coal powder and centrifuging to obtain a precipitate; dissolving the precipitate with ethanol, adding concentrated sulfuric acid, oxidizing at 60-80 °C for 30-60 min, then oscillating and reacting at 40-60 °C for 45-75 min, filtering after the reaction ends, and drying to obtain fulvic acid powder; grinding the fulvic acid powder to a nano-sized particle size, adding deionized water for ultrasonic treatment, centrifuging and drying after the treatment ends to obtain active nano fulvic acid.

[0008] Preferably, the particle size of the weathered coal powder is 40-80 mesh, washed 1-2 times with distilled water, and centrifuged at 5000-7000 rpm for 4-6 min.

[0009] Preferably, the volume ratio of the ethanol: weathered coal coarse coal: concentrated sulfuric acid is 4-8:1:0.05-0.2.

[0010] More preferably, the mass fraction of the ethanol is 80%-90%; the mass fraction of the concentrated sulfuric acid is 98%.

[0011] Preferably, the fulvic acid powder is ground by a planetary ball mill, and the grinding time is 10-14 h.

[0012] Preferably, the ratio of the fulvic acid powder to deionized water is 1 g: 80-120 mL, the ultrasonic power is 550-650 W, and the time is 2-4 h.

[0013] The present invention also provides the active nano-fulvic acid prepared by the above preparation method.

[0014] The present invention also provides an active nano-fulvic acid biological fertilizer, which is prepared by mixing the above active nano-fulvic acid and a synergist in a mass ratio of 70%-80%: 20%-30%; the synergist includes 1-3 parts of rare earth, 3-5 parts of chitosan, 2-5 parts of microbial inoculum, 6-10 parts of amino acid, and 3-8 parts of seaweed extract.

[0015] The present invention also provides the application of the above active nano-fulvic acid biological fertilizer in crop planting.

[0016] Preferably, the active nano-fulvic acid biological fertilizer is applied as a base fertilizer, and the application rate is 20-40 kg / mu.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The unique preparation method of the present invention greatly improves the performance of the active nano-fulvic acid. Using ethanol to dissolve the weathered coal powder can selectively extract low-molecular-weight fulvic acid and inhibit the dissolution of macromolecular humic acid, laying a foundation for the subsequent preparation of high-activity fertilizers. The concentrated sulfuric acid oxidation process is carried out under specific temperature and time conditions, effectively cracking the macromolecular structure of humic acid to generate small-molecular active fulvic acid, significantly enhancing the biological activity of fulvic acid. Nano-scale grinding breaks the fulvic acid powder into nano-scale particle sizes, greatly increasing the specific surface area and significantly improving the contact efficiency with plant roots, which is more conducive to plant nutrient absorption. Ultrasonic treatment further activates the activity of fulvic acid, making its internal structure more stable and increasing the number of active sites. The active nano-fulvic acid obtained by this preparation method has the characteristics of high biological activity, high specific surface area, good water solubility and dispersibility, etc., and can provide nutrients for plants more efficiently and promote plant growth.

[0019] When the active nano - fulvic acid of the present invention is applied in combination with a synergist, a remarkable synergistic effect is further demonstrated. The prepared active nano - fulvic acid bio - fertilizer can not only significantly promote seed germination and crop growth, but also effectively improve the soil environment, enhance soil fertility and microbial activity, ultimately increasing crop yield and improving quality, providing strong support for the sustainable development of agriculture. Detailed implementation manners

[0020] The present invention provides a preparation method of active nano - fulvic acid, comprising the following steps: washing weathered coal powder, centrifuging to obtain a precipitate; dissolving the precipitate in ethanol, adding concentrated sulfuric acid, oxidizing at 60 - 80 °C for 30 - 60 min, then oscillating and reacting at 40 - 60 °C for 45 - 75 min, filtering after the reaction ends, and drying to obtain fulvic acid powder; grinding the fulvic acid powder to a nano - scale particle size, adding deionized water for ultrasonic treatment, centrifuging and drying after the treatment ends to obtain the active nano - fulvic acid bio - fertilizer.

[0021] In the present invention, it is preferred that the particle size of the weathered coal powder is 40 - 80 mesh; more preferably, the particle size is 60 mesh; it is preferred to wash with distilled water 1 - 2 times, centrifuge at 5000 - 7000 rpm for 4 - 6 min, and more preferably wash with distilled water 1 time and centrifuge at 6000 rpm for 5 min. Washing and centrifugal precipitation can remove sediment, soluble salts and inorganic impurities in the raw weathered coal, avoiding interference of impurities in the subsequent reaction for fulvic acid extraction.

[0022] In the present invention, it is preferred that the mass fraction of ethanol is 80% - 90%, more preferably 85%; the mass fraction of concentrated sulfuric acid is 98%. It is preferred that the volume ratio of ethanol:raw weathered coal:concentrated sulfuric acid is 4 - 8:1:0.05 - 0.2, more preferably 6:1:0.1, and stir evenly. It is preferred to oxidize the above - mentioned mixed system at 65 - 75 °C for 35 - 50 min, then oscillate and react at 45 - 55 °C for 55 - 65 min; more preferably oxidize at 70 °C for 40 min, then oscillate and react at 50 °C for 60 min. Ethanol, as a polar solvent, can dissolve low - molecular - weight fulvic acid in weathered coal, while inhibiting the dissolution of macromolecular humic acids (such as humic acid), realizing selective extraction; concentrated sulfuric acid, as a strong oxidant, cleaves the macromolecular structure of humic acid under acidic conditions to generate small - molecule active fulvic acid; and the oscillating reaction promotes the homogeneity of the reaction system, accelerates the exposure of the side - chain functional groups of fulvic acid molecules, and enhances their biological activity.

[0023] In the present invention, the preferred filtration method is suction filtration. Further preferably, the residue is washed with ethanol after suction filtration. More preferably, the mass fraction of ethanol is 85%. The preferred drying method is freeze-drying. Further preferably, it is freeze-dried at -50°C for 1 - 2 h, and more preferably for 1.5 h. Washing can remove unreacted concentrated sulfuric acid, inorganic salts, and undissolved humic acid residues, avoiding the corrosion of plant roots by residual acid; freeze-drying can prevent the inactivation of thermosensitive functional groups of fulvic acid during conventional drying and maintain the porous structure, improving the efficiency of subsequent nano-grinding.

[0024] In the present invention, the fulvic acid powder is preferably ground by a planetary ball mill for 10 - 14 h, and further preferably for 12 h. Grinding can break the fulvic acid powder to the nanoscale (<100 nm), increase the specific surface area, and enhance the contact efficiency with plant roots.

[0025] In the present invention, the ratio of fulvic acid powder to deionized water is preferably 1 g:80 - 120 mL, and further preferably 1 g:100 mL. The preferred power of ultrasonic treatment is 550 - 650 W, and further preferably 600 W; the time is 2 - 4 h, and further preferably 3 h. As an implementable method, an ultrasonic cell disrupter is used for ultrasonic treatment, and after the treatment is completed, it is cooled to room temperature. Ultrasonic treatment further enhances the biological activity of the fulvic acid powder.

[0026] In the present invention, the preferred centrifugation parameters are 6000 - 10000 rpm for 5 - 15 min; further preferably 8000 rpm for 10 min. The preferred drying method is freeze-drying. Further preferably, it is freeze-dried at -50°C for 1 - 2 h.

[0027] The present invention also provides the active nano-fulvic acid prepared by the above preparation method.

[0028] The present invention also provides an active nano fulvic acid biological fertilizer, which is prepared by mixing the above-mentioned active nano fulvic acid and a synergist in a mass ratio of 70% - 80%: 20% - 30%, and further preferably 75%: 25%. The synergist of the present invention includes 1 - 3 parts of rare earth, 3 - 5 parts of chitosan, 2 - 5 parts of microbial inoculum, 6 - 10 parts of amino acids, and 3 - 8 parts of seaweed extract; preferably 2 parts of rare earth, 4 parts of chitosan, 4 parts of microbial inoculum, 8 parts of amino acids, and 5 parts of seaweed extract; further preferably, the rare earth contains 30 - 50 wt% of rare earth chloride and 50 - 70 wt% of rare earth sulfate, and more preferably contains 40 wt% of rare earth chloride and 60 wt% of rare earth sulfate; further preferably, the microbial inoculum is nitrogen-fixing bacteria, and more preferably Azospirillum. In the synergist of the present invention, the rare element ions in the rare earth act as plant enzyme activators, which can promote the transmembrane transport of nutrient ions in fulvic acid; the cationic polysaccharide of chitosan fixes the fulvic acid nanoparticles through electrostatic adsorption, and slowly releases nutrients; the microbial inoculum and fulvic acid synergistically fix nitrogen, reducing the dosage of chemical nitrogen fertilizer; amino acids directly serve as carbon and nitrogen sources to promote the proliferation of microbial inoculum, and at the same time chelate medium and trace elements to improve the nutrient availability; the seaweed extract contains natural growth hormones (such as alginic acid, cytokinin, etc.), which can enhance the absorption response of plants to fulvic acid.

[0029] The present invention also provides the application of the above-mentioned active nano fulvic acid biological fertilizer in crop planting. The types of crops of the present invention are not limited, and the active nano fulvic acid biological fertilizer is applicable to common field crops (such as wheat, corn, and rice) and cash crops (such as vegetable crops, fruit trees, oil crops, and tobacco). Preferably, the active nano fulvic acid biological fertilizer is applied as a basal fertilizer, and the application rate is 20 - 40 kg / mu, further preferably 25 - 35 kg / mu, and more preferably 30 kg / mu. When applied as a basal fertilizer, the active nano fulvic acid biological fertilizer of the present invention can form a slow-release carrier after being combined with soil particles, and it also takes time for the microorganisms in the synergist to colonize in the roots. Deep application of the basal fertilizer can synchronously match the crop growth cycle, improve the nutrient utilization efficiency of the crop, and promote its growth and development.

[0030] The following combines examples to detail the technical solutions provided by the present invention, but they cannot be understood as limiting the protection scope of the present invention.

[0031] Example 1

[0032] An active nano fulvic acid is prepared in the following manner:

[0033] (1) Weigh the naturally air-dried weathered coal, crush it to 60 mesh, wash it once with distilled water, and then centrifuge (6000 rpm, 5 min) to obtain a precipitate;

[0034] (2) Dissolve the precipitate with 85% ethanol solution, add concentrated sulfuric acid, stir evenly, oxidize at 70 °C for 40 min, and then keep it oscillating at a constant temperature of 50 °C for 60 min; the volume ratio of ethanol, weathered coal and concentrated sulfuric acid is 6:1:0.1;

[0035] (3) After the reaction is completed, perform suction filtration, wash the residue with 85% ethanol solution, and conduct freeze-drying (-50 °C, 1.5 h) to obtain fulvic acid powder, which is dried and stored for later use;

[0036] (4) Ball-mill the obtained fulvic acid powder with a planetary ball mill for 12 h;

[0037] (5) Pour the ball-milled product obtained after ball-milling into a beaker, add deionized water at a solid-liquid ratio of 1 g:100 mL, and ultrasonically treat it with an ultrasonic cell disruptor for 3 h, with an ultrasonic power of 600 W;

[0038] (6) Centrifuge the liquid after ultrasonic treatment at room temperature (8000 rpm, 10 min) and then conduct freeze-drying (-50 °C, 1.5 h) to obtain active nano-fulvic acid.

[0039] Example 2

[0040] An active nano-fulvic acid is prepared as follows:

[0041] (1) Weigh air-dried weathered coal, crush it to 80 mesh, wash it twice with distilled water, and then centrifuge (5000 rpm, 6 min) to obtain a precipitate;

[0042] (2) Dissolve the precipitate of the raw coal sample with 90% ethanol solution, add concentrated sulfuric acid, stir evenly, oxidize at 60 °C for 60 min, and then keep it oscillating at a constant temperature of 40 °C for 75 min; the volume ratio of ethanol, weathered coal and concentrated sulfuric acid is 4:1:0.05;

[0043] (3) After the reaction is completed, perform suction filtration, wash the residue with 90% ethanol solution, and conduct freeze-drying (-50 °C, 2 h) to obtain fulvic acid powder, which is dried and stored for later use;

[0044] (4) Ball-mill the obtained fulvic acid powder with a planetary ball mill for 14 h;

[0045] (5) Pour the ball-milled product obtained after ball-milling into a beaker, add deionized water at a solid-liquid ratio of 1 g:80 mL, and ultrasonically treat it with an ultrasonic cell disruptor for 2 h, with an ultrasonic power of 650 W;

[0046] (6) Centrifuge the liquid after ultrasonic treatment at room temperature (6000 rpm, 15 min) and then conduct freeze-drying (-50 °C, 2 h) to obtain active nano-fulvic acid.

[0047] Example 3

[0048] An active nano fulvic acid is prepared as follows:

[0049] (1) Weigh the weathered coal that has been naturally air-dried, crush it to 40 mesh, wash it once with distilled water, and then centrifuge (7000 rpm, 4 min) to obtain a precipitate;

[0050] (2) Dissolve the precipitated crude coal sample with 80% ethanol solution, add concentrated sulfuric acid, stir evenly, oxidize it at 80 °C for 30 min, and then keep it oscillating at a constant temperature of 60 °C for 45 min; the volume ratio of ethanol, weathered coal and concentrated sulfuric acid is 8:1:0.2;

[0051] (3) After the reaction is completed, perform suction filtration, wash the residue with 80% ethanol solution, and perform freeze-drying (-50 °C, 1 h) to obtain fulvic acid powder, which is dried and stored for later use;

[0052] (4) Ball-mill the obtained fulvic acid powder with a planetary ball mill for 10 h;

[0053] (5) Pour the ball-milled product obtained after ball-milling into a beaker, add deionized water at a solid-liquid ratio of 1 g:120 mL, and ultrasonically treat it with an ultrasonic cell disruptor for 4 h, with an ultrasonic power of 550 W;

[0054] (6) Centrifuge the liquid after ultrasonic treatment at room temperature (10000 rpm, 5 min) and then perform freeze-drying (-50 °C, 1 h) to obtain active nano fulvic acid.

[0055] Example 4

[0056] An active nano fulvic acid biological fertilizer and its application method are as follows:

[0057] (1) Weigh 75 kg of the active nano fulvic acid in Example 1 and 25 kg of synergist to obtain 100 kg of active nano fulvic acid biological fertilizer; the synergist is made of 2 parts of rare earth (a mixture of 40 wt% rare earth chloride and 60 wt% rare earth sulfate), 4 parts of chitosan, 4 parts of microbial inoculant (Azospirillum), 8 parts of amino acid and 5 parts of seaweed extract by mass;

[0058] (2) As a crop base fertilizer, apply the active nano fulvic acid biological fertilizer at a rate of 30 kg / mu and deeply plow and mix evenly.

[0059] Example 5

[0060] An active nano fulvic acid biological fertilizer and its application method are as follows:

[0061] (1) Weigh 80 kg of the active nano fulvic acid from Example 2 and 20 kg of the synergist to obtain 100 kg of the active nano fulvic acid bio-fertilizer. The synergist is made up of 1 part of rare earth (a mixture of 30 wt% rare earth chloride and 70 wt% rare earth sulfate), 3 parts of chitosan, 2 parts of microbial inoculant (Azospirillum), 6 parts of amino acid, and 3 parts of seaweed extract by mass.

[0062] (2) As a base fertilizer for crops, apply the active nano fulvic acid bio-fertilizer at a rate of 20 kg per mu and deeply plow and mix evenly.

[0063] Example 6

[0064] An active nano fulvic acid bio-fertilizer and its application method are as follows:

[0065] (1) Weigh 70 kg of the active nano fulvic acid from Example 3 and 30 kg of the synergist to obtain 100 kg of the active nano fulvic acid bio-fertilizer. The synergist is made up of 3 parts of rare earth (a mixture of 50 wt% rare earth chloride and 50 wt% rare earth sulfate), 5 parts of chitosan, 5 parts of microbial inoculant (Azospirillum), 10 parts of amino acid, and 8 parts of seaweed extract by mass.

[0066] (2) As a base fertilizer for crops, apply the active nano fulvic acid bio-fertilizer at a rate of 40 kg per mu and deeply plow and mix evenly.

[0067] Test Example 1

[0068] Effect of different fertilizer solutions on tomato seed germination

[0069] Prepare the seed culture solution by diluting the following fertilizers 2000 times with distilled water:

[0070] Treatment 1: Commercially available fulvic acid fertilizer, not extracted with ethanol, and not subjected to oxidation, ultrasonic treatment, grinding, etc.

[0071] Treatment 2: The active nano fulvic acid bio-fertilizer of Example 4

[0072] Treatment 3: Different from Treatment 2 in that it is not subjected to nano grinding and ultrasonic treatment and does not contain a synergist.

[0073] Treatment 4: Different from Treatment 2 in that it is only subjected to ultrasonic treatment.

[0074] Treatment 5: Different from Treatment 2 in that the nano fulvic acid is not activated and the synergist is used alone.

[0075] Treatment 6: Different from Treatment 2 in that it is only subjected to nano grinding treatment.

[0076] Treatment 7: Different from Treatment 2 in that it is only subjected to ultrasonic treatment and contains a synergist.

[0077] Treatment 8: The difference from Treatment 2 is that only nano-grinding and ultrasonic treatment are carried out;

[0078] Treatment 9: The difference from Treatment 2 is that only nano-grinding is carried out and it contains synergists.

[0079] Each seedling tray is lined with two layers of filter paper and diluted seed culture solution at 2000 times. Each seedling tray is divided into three equal parts, that is, equally divided into 3 replicates. 50 seeds of large red tomatoes (Cooperation 903) are placed in each replicate and germinated in a light incubator at 25°C. Observe and record the number of germinated seeds every day. Each treatment is supplemented with 50 mL of the corresponding seed culture solution every 1 day to ensure sufficient water supply. The germination potential, germination number and vigor index are measured.

[0080] Germination potential (%) = Number of germinated seeds in 3 days / Number of test seeds × 100%;

[0081] Germination rate (%) = Number of germinated seeds in 7 days / Number of test seeds × 100%;

[0082] Vigor index VI = Germination index Gi × Total length;

[0083] Germination index Gi = Σ(Gt / Dt), where Gt is the number of germinated seeds on day t and Dt is the corresponding germination days.

[0084] Test results:

[0085] As shown in Table 1, the germination potential, germination rate and vigor index of Treatment 2 are significantly higher than those of Treatment 1. All indicators of Treatments 3 - 9 are between Treatment 1 and Treatment 2, indicating that the promotion effect of nano-grinding, ultrasonic treatment alone, or the synergist alone on tomato seed germination is not as good as that of the active nano fulvic acid bio-fertilizer treatment in Example 4. There is a synergistic effect between nano-grinding, ultrasonic treatment and the synergist, which jointly promotes the germination of tomato seeds, improves the germination potential, germination rate and vigor index of the seeds, and enhances the germination ability of the seeds and the robustness of the seedlings.

[0086] Table 1 Effects of different fertilizer solution treatments on tomato seed germination

[0087]

[0088]

[0089] Test Example 2

[0090] Effects of different fertilization treatments on tomato plants

[0091] A field greenhouse experiment is carried out. Fertilizers are uniformly added to the soil according to the following treatments. Each treatment has 4 replicates, and the plants at four points are detected for each replicate.

[0092] Treatment 1: 30 kg / mu of the active nano-fulvic acid biofertilizer of Example 4;

[0093] Treatment 2: The difference from treatment 1 is that it was not nano-milled and ultrasonicated, and did not contain enhancers;

[0094] CK: The difference from treatment 1 is that only basal fertilizer was applied.

[0095] The base fertilizers for the three fertilization treatments were 150 kg of commercial organic fertilizer, 30 kg of urea, 80 kg of superphosphate and 18 kg of potassium sulfate per mu, and the topdressing was the same.

[0096] 60 days after transplanting, measure the height from the bottom of the tomato main stem to the top of the plant and the diameter of the bottom of the main stem.

[0097] Test results:

[0098] As shown in Table 2, the tomato plants in treatment 1 performed best in terms of height and diameter. Treatment 2 had a certain growth advantage over CK, but not as obvious as treatment 1. This shows that the active nano-fulvic acid biofertilizer after nano-grinding, ultrasonic treatment and addition of synergist can significantly promote the nutritional growth of tomato plants, making the plants taller and the stems thicker, which helps the tomato plants to better photosynthesize and transport nutrients, laying a good foundation for subsequent flowering and fruiting.

[0099] Table 2 Effects of different fertilization treatments on tomato plant growth

[0100]

[0101]

[0102] Test Example 3

[0103] Field experiment on the effects of different fertilization treatments on soil environment, growth and yield of carrot

[0104] Before planting carrots, three different fertilization treatments were set up as follows:

[0105] Treatment 1: Apply base fertilizer + 30 kg / mu of active nano fulvic acid biofertilizer of Example 4;

[0106] Treatment 2: The difference from treatment 1 is that it was not nano-milled and ultrasonicated, and did not contain enhancers;

[0107] CK: The difference from treatment 1 is that only basal fertilizer was applied.

[0108] The base fertilizers for the three fertilization treatments were 150 kg of commercial organic fertilizer, 20 kg of urea, 20 kg of superphosphate and 5 kg of potassium sulfate per mu, and the topdressing was the same.

[0109] After the carrots were harvested, the five-point sampling method was used. For each treatment, the nutrient content and enzyme activity of the soil in the 0-10 cm soil layer of the planting area were measured, and the yield of each treatment was measured.

[0110] Test results:

[0111] As shown in Tables 3 to 5, in terms of soil nutrients, the total nitrogen, total phosphorus, available potassium, available phosphorus, and organic matter content of Treatment 1 were all higher than those of Treatment 2 and CK, indicating that the active nano fulvic acid biological fertilizer of the present invention can effectively improve soil fertility and provide more sufficient nutrients for the growth of carrots. In terms of soil enzyme activity, the urease, phosphatase, and sucrase activities of Treatment 1 were also the highest. These enzymes are closely related to the transformation and utilization of nutrients in the soil. Higher enzyme activity is conducive to the decomposition of organic matter in the soil and the release of nutrients, promoting the absorption of nutrients by carrots. The carrots in Treatment 1 were significantly superior to Treatment 2 and CK in terms of mu yield, average plant height, carrot length, and commodity rate, with an increase in production of 10.14%. This shows that the active nano fulvic acid biological fertilizer can not only improve the soil environment but also significantly promote the growth and development of carrots, increasing yield and quality.

[0112] Table 3 Effects of different fertilization treatments on soil nutrients in carrot planting areas

[0113] Treatment Total nitrogen g / kg Total phosphorus g / kg Available potassium mg / kg Available phosphorus mg / kg Organic matter g / kg 1 3.54 0.96 264.7 347.2 21.5 2 3.28 0.87 231.3 326.4 17.7 CK 3.10 0.82 218.5 285.8 13.4

[0114] Table 4 Effects of different fertilization treatments on soil enzyme activity in carrot planting areas

[0115]

[0116]

[0117] Table 5 Effects of different fertilization treatments on carrot growth and yield

[0118] Yield per mu kg Average plant height cm Carrot length cm Commodity rate % Yield increase % 1 5637 75.65 18.73 78.5 10.14 2 5403 72.91 18.92 75.2 5.57 CK 5118 71.54 17.81 73.5 /

[0119] Test Example 4

[0120] Effects of different fertilization treatments on the growth of tobacco seedlings

[0121] Before transplanting tobacco seedlings, 3 different fertilization treatments were set up as follows:

[0122] Treatment 1: Applying basal fertilizer + 30 kg / mu of the active nano fulvic acid biological fertilizer of Example 4;

[0123] Treatment 2: Different from Treatment 1 in that it was not nano-ground and ultrasonically treated and did not contain synergists;

[0124] CK: Different from Treatment 1 in that only basal fertilizer was applied.

[0125] For the basal fertilizers of the three fertilization treatments, 30 kg of ternary compound fertilizer (N:P2O5:K2O = 12%:12%:25%), 20 kg of oil cake / cow dung, and 40 kg of superphosphate were applied per mu, and the topdressing was the same.

[0126] Two months after transplanting the tobacco seedlings, 30 tobacco seedlings were randomly pulled out from each treatment for the measurement of plant height and leaf area.

[0127] Test results:

[0128] As shown in Table 6, the growth rates of plant height and leaf area of the tobacco seedlings in Treatment 1 were significantly higher than those in Treatment 2 and CK. Although Treatment 2 had a certain growth advantage over CK, it was far less than Treatment 1. This indicates that the active nano fulvic acid biological fertilizer has a significant promoting effect on the vegetative growth of tobacco seedlings, can increase the plant height and leaf area of tobacco seedlings, improve the photosynthesis efficiency of tobacco seedlings, provide strong support for the later growth and quality formation of tobacco, and contribute to improving the yield and quality of tobacco.

[0129] Table 6 Effects of different fertilization treatments on the growth of tobacco seedlings

[0130] Treatment Plant height m Plant height growth rate % <![CDATA[Leaf area / m 2 > Leaf area growth rate % 1 1.668 40.88 0.182 31.88 2 1.582 33.61 0.150 8.70 CK 1.184 / 0.138 /

[0131] It can be seen from Test Examples 1 to 4 that the weathered coal powder is made into active nano humic acid through ethanol extraction, concentrated sulfuric acid oxidation, grinding and ultrasonic treatment of the present invention, and combined with a synergist to make an active nano humic acid biological fertilizer for application. Compared with the currently commercially available humic acid fertilizers, it has the effects of promoting seed germination, promoting crop growth, improving the soil environment, and enhancing crop yield and quality.

[0132] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of active nano fulvic acid, characterized in that, It includes the following steps: Wash weathered coal powder, and centrifuge to obtain a precipitate; dissolve the precipitate with ethanol, add concentrated sulfuric acid, oxidize at 60 - 80 °C for 30 - 60 min, then react with oscillation at 40 - 60 °C for 45 - 75 min. After the reaction ends, filter and dry to obtain fulvic acid powder; grind the fulvic acid powder to a nanoscale particle size, add deionized water and perform ultrasonic treatment. After the treatment ends, centrifuge and dry to obtain active nano-fulvic acid.

2. The preparation method according to claim 1, characterized in that, The particle size of the weathered coal powder is 40 - 80 mesh, wash it with distilled water 1 - 2 times, and centrifuge at 5000 - 7000 rpm for 4 - 6 min.

3. The preparation method according to claim 1, characterized in that, The volume ratio of the ethanol: weathered coal coarse coal: concentrated sulfuric acid is 4 - 8:1:0.05 - 0.

2.

4. The preparation method according to claim 1 or 3, characterized in that, The mass fraction of the ethanol is 80% - 90%; the mass fraction of the concentrated sulfuric acid is 98%.

5. The preparation method according to claim 1, characterized in that, The fulvic acid powder is ground by a planetary ball mill, and the grinding time is 10 - 14 h.

6. The preparation method according to claim 1, characterized in that, The ratio of the fulvic acid powder to deionized water is 1 g:80 - 120 mL, the ultrasonic power is 550 - 650 W, and the time is 2 - 4 h.

7. Active nano-fulvic acid prepared by the preparation method according to any one of claims 1 - 6.

8. An active nano fulvic acid biological fertilizer, characterized in that, It is made by mixing the active nano-fulvic acid according to claim 7 and a synergist in a mass ratio of 70% - 80%:20% - 30%; the synergist includes 1 - 3 parts of rare earth, 3 - 5 parts of chitosan, 2 - 5 parts of microbial inoculum, 6 - 10 parts of amino acid, and 3 - 8 parts of seaweed extract.

9. Application of the active nano-fulvic acid biological fertilizer according to claim 8 in crop planting.

10. The application according to claim 9, characterized in that, The active nano-fulvic acid biological fertilizer is applied as a base fertilizer, and the application rate is 20 - 40 kg / mu.

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