Drought-resistant fertilizer complex foliar fertilizer for wheat and preparation method thereof

Abstract

This invention relates to the field of crop yield enhancement technology, specifically to a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat and its preparation method. It is prepared from the following raw materials in parts by weight: 54-60 parts of basic foliar fertilizer solution, 5 parts of plant-derived carbon-nitrogen solution, 5 parts of potassium humate solution, 20 parts of photosynthetic bacteria agent, 0.05 parts of polyether-modified trisiloxane, 1 part of polyethylene glycol 2000, 0.3 parts of xanthan gum, and 8.65-14.65 parts of deionized water containing 0.001% 28-homobrassinolide. The basic foliar fertilizer solution includes 12-15 parts of urea, 9-12 parts of potassium dihydrogen phosphate, 0.4 parts of trace elements, and 32.6 parts of deionized water. This invention solves the problems of existing wheat foliar fertilizers having limited function, failing to simultaneously achieve multiple effects such as nutrient supplementation, improved drought resistance, increased photosynthetic efficiency, and stress-resistant yield enhancement, as well as the problems of insufficient spreadability and low absorption and utilization rates due to unscientific adjuvants.

Description

Technical Field

[0001] This invention relates to the field of crop yield enhancement technology, specifically to a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat and its preparation method. Background Technology

[0002] Wheat is a dryland grain crop, frequently encountering natural disasters such as periodic droughts and low-temperature freezing damage during its growth period. Drought, especially in dryland wheat, is a major factor limiting high yields. Wheat is a major summer grain crop, and stable and high yields are directly related to national food security. When wheat encounters adverse conditions such as drought and low temperatures during its growth period, irrigation and foliar fertilization can promote growth. This is particularly important in fields with weak seedlings or dryland wheat where timely irrigation is impossible or unavailable; foliar fertilization can supplement necessary nutrients, enhance resistance, improve photosynthetic capacity, increase dry matter accumulation, and promote healthy growth or resist adverse conditions to achieve stable and high yields. Foliar fertilizer, as a channel for root absorption of nutrients or beneficial substances, has advantages such as rapid onset, high efficiency, and good effects. Especially when wheat encounters adverse conditions such as drought, and when root absorption capacity is weak during the grain-filling stage, foliar fertilization is a primary measure for nutrient supplementation and absorption, which is crucial for ensuring stable and increased wheat yields. Common foliar fertilizers mainly supplement the macro- and micro-elements required by wheat, such as nitrogen, phosphorus, potassium, iron, and manganese. In addition, some new types of foliar fertilizers that have emerged in recent years also contain amino acids and plant growth regulators, in order to better supplement nutrients and promote growth and increase yield.

[0003] In wheat production, especially in dryland wheat production, foliar fertilizer application offers numerous advantages in stress resistance and yield increase. However, existing foliar fertilizers often suffer from limitations, such as limited functionality. Therefore, there is a demand for a compound foliar fertilizer that, through a single application, can supplement nutrients, improve drought resistance, withstand low temperatures and prevent high temperatures, enhance photosynthetic efficiency, promote dry matter accumulation, and achieve a synergistic effect of stress resistance, growth promotion, and yield increase. Currently, the demand for "multi-effect" foliar fertilizers is becoming increasingly diversified, but such multifunctional compound foliar fertilizers are relatively scarce. In practice, many farmers simply mix macro-elements, micro-elements, growth regulators, plant inducing factors, and microbial agents on-site based on experience to achieve "multi-effect" results, but this often falls short of expectations. This is because such nutrient mixing is arbitrary, the ratios are unreasonable, and nutrient compatibility and synergy are poor. Furthermore, there are issues with the unscientific use of adjuvants and dosages, as well as poor spreadability and wettability. This is especially problematic in northern regions during droughts, where low air humidity and rapid evaporation further hinder the spreadability and absorption of foliar fertilizers. Therefore, the current situation where wheat foliar fertilizers cannot simultaneously provide multiple nutrients, protect leaves and roots, delay senescence, improve photosynthetic efficiency, and promote dry matter accumulation and transport to achieve stress resistance and increased yield, particularly under adverse conditions like drought, remains a major challenge for the industry. Developing a compound foliar fertilizer that significantly enhances wheat's absorption and utilization of nutrients and soil moisture, improves photosynthetic efficiency, and meets multiple needs for drought resistance and increased yield remains a key challenge.

[0004] Therefore, it is necessary to invent a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat and its preparation method. Summary of the Invention

[0005] To address the problems of existing wheat foliar fertilizers having limited functions, failing to simultaneously achieve multiple effects such as nutrient supplementation, drought resistance enhancement, photosynthetic efficiency improvement, and stress resistance and yield increase, as well as the issues of unscientific adjuvants leading to insufficient spreadability and low absorption and utilization rates, this invention provides a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat and its preparation method.

[0006] This invention is achieved using the following technical solution:

[0007] A drought-resistant foliar fertilizer for wheat, comprising fertilizer and bacteria, is prepared from the following raw materials in parts by weight: 54-60 parts of basic foliar fertilizer solution, 5 parts of plant-derived carbon-nitrogen solution, 5 parts of potassium humate solution, 20 parts of photosynthetic bacteria agent, 0.05 parts of polyether-modified trisiloxane, 1 part of polyethylene glycol 2000, 0.3 parts of xanthan gum, and 8.65-14.65 parts of deionized water containing 0.001% 28-homobrassinolide; wherein the basic foliar fertilizer solution comprises 12-15 parts of urea, 9-12 parts of potassium dihydrogen phosphate, 0.4 parts of trace elements, and 32.6 parts of deionized water; the plant-derived carbon-nitrogen solution has a solids content of 10%; the potassium humate solution contains 20% potassium humate; and the photosynthetic bacteria agent has a viable count ≥50 × 10⁻⁶. 8 CFU / mL.

[0008] A method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat includes the following steps:

[0009] S1: Dissolve 12-15 parts of urea, 9-12 parts of potassium dihydrogen phosphate and 0.4 parts of trace elements in 32.6 parts of deionized water, adjust the pH to 6.0-6.5, and obtain the basic foliar fertilizer solution.

[0010] S2: Wheat straw was steam-exploded and enzymatically hydrolyzed to obtain 5 portions of plant-derived carbon-nitrogen liquid;

[0011] S3: The lignite was alkalized and purified to obtain 5 parts of potassium humate solution;

[0012] S4: Expand and proliferate the photosynthetic bacteria strain to obtain 20 portions of photosynthetic bacteria agent;

[0013] S5: Add the basic foliar fertilizer solution obtained in step S1, the plant-derived carbon and nitrogen solution obtained in step S2, the potassium humate solution obtained in step S3, and the photosynthetic bacteria agent obtained in step S4 to deionized water containing 0.001% of 28-homobrassinolide, mix evenly, and obtain the fertilizer-bacteria compound foliar fertilizer stock solution.

[0014] S6: Add 0.05 parts of polyether-modified trisiloxane and 1 part of polyethylene glycol 2000 to the stock solution of the fertilizer-bacterial compound foliar fertilizer for emulsification, then add 0.3 parts of xanthan gum and stir. Finally, add deionized water containing 0.001% 28-homobrassinolide to bring the total mass to 100 parts, thus obtaining the drought-resistant fertilizer-bacterial compound foliar fertilizer.

[0015] Furthermore, in step S1, the trace elements include at least three of chelated manganese, chelated iron, chelated magnesium, and boron.

[0016] Further, in step S2, the preparation method of the plant-derived carbon-nitrogen liquid specifically includes: chopping wheat straw to 3cm, steam-exploding it, pulverizing it through a 20-mesh sieve, then adding 40 U / g of cellulase and 20 U / g of xylanase based on the dry weight of the wheat straw, adjusting the pH to 4.5-5, controlling the temperature at 50℃, and performing enzymatic hydrolysis at 100 rpm for 30 h to obtain a plant-derived polysaccharide liquid; then adding pure soybean powder to the plant-derived polysaccharide liquid, wherein the dry weight of the pure soybean powder is 1 / 10 of the dry weight of the wheat straw, adjusting the pH to 8-8.5, adding 20 U / g of alkaline protease and 5 U / g of neutral protease based on the dry weight of the wheat straw, controlling the temperature at 50℃, and performing enzymatic hydrolysis at 100 rpm for 6 h, terminating the reaction, adjusting the pH to 6-7, and concentrating until the solid content is 10% to obtain the plant-derived carbon-nitrogen liquid.

[0017] Further, in step S3, the method for preparing the potassium humate solution specifically includes: crushing lignite with a humic acid content higher than 60% through a 50-mesh sieve, ball milling, oxidizing it at 70°C with a mixed acid of sulfuric acid and nitric acid in a volume ratio of 7:3 for 40 minutes, then adding a potassium hydroxide solution with a mass concentration of 15%, reacting at 60°C for 1 hour, the reaction solution undergoing sedimentation and solid-liquid separation, adjusting the pH of the separated solution to 2 to precipitate humic acid, purifying and desalting, then adjusting the pH to 7, and concentrating it to a potassium humate content of 20% to obtain the potassium humate solution.

[0018] Further, in step S4, the preparation method of the photosynthetic bacteria agent specifically includes: mixing *Rhodopseudomonas palustris* and *Rhodopseudomonas capsulatum* at a viable count ratio of 5:1, inoculating into a photosynthetic bacteria culture medium, and culturing under sealed light for 5 days at a light intensity of 3000 Lux and a temperature of 30℃ to obtain a viable count ≥50×10⁻⁶. 8 CFU / mL photosynthetic bacteria agent; the photosynthetic bacteria culture medium consists of 3.5g sodium acetate, 0.8g ammonium chloride, 1.0g potassium dihydrogen phosphate, 0.5g magnesium sulfate, and 1.5g yeast extract per liter of deionized water, with a pH of 7.0-7.5.

[0019] Furthermore, in step S6, the temperature is controlled at 35°C throughout the emulsification process.

[0020] Application of a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat, wherein the drought-resistant fertilizer-bacterial compound foliar fertilizer is applied to the leaves of wheat from the greening stage to the grain-filling stage.

[0021] Furthermore, under drought stress conditions, the aforementioned drought-resistant fertilizer-bacterial compound foliar fertilizer is sprayed on the leaves once every 10-15 days.

[0022] This invention provides a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat and its preparation method, which has the following advantages compared with the prior art:

[0023] 1. By introducing urea as a nitrogen source, combined with potassium dihydrogen phosphate and trace elements, it effectively and quickly replenishes the nitrogen, phosphorus, potassium, manganese, iron and other nutrients required for wheat growth, promotes balanced nutrient absorption, and leverages urea's moisture-absorbing and moisture-retaining properties, rapid penetration, and ability to carry similar nutrients into the plant body as an adjuvant to enhance the efficacy of foliar fertilizer absorption, which can effectively improve the absorption and utilization efficiency of wheat, especially dryland wheat.

[0024] 2. By introducing wheat straw and pure soybean powder and enzymatically hydrolyzing them with a mixed enzyme solution to obtain plant-derived carbon and nitrogen solution, it can not only achieve a chelation and synergistic effect, but also supplement small and medium molecule carbon and nitrogen sources, extend the nutrient period of foliar fertilizer, reduce the number of sprayings, improve drought resistance, low temperature resistance and other stress resistance, and enhance the synergistic utilization effect of foliar fertilizer.

[0025] 3. Introducing potassium humate and 28-homobrassinolide can enhance the drought resistance of dryland wheat, promote growth, increase dry matter accumulation and translocation, and achieve the effects of stress resistance, growth promotion and yield increase.

[0026] 4. By introducing photosynthetic bacteria, the photosynthetic efficiency of wheat can be improved, nitrogen fixation and nitrogen absorption can be promoted. The bacteria and their secondary metabolites can induce and enhance the wheat's resistance to drought, low temperature and high temperature, and work in coordination with nitrogen, phosphorus, potassium and trace elements, plant carbon and nitrogen sources, potassium humate, etc., to jointly promote nutrient absorption, improve photosynthetic efficiency, increase dry matter accumulation, and achieve stress resistance and yield increase.

[0027] 5. By introducing highly efficient surfactants and wetting agents such as organosilicon and polyethylene glycol 2000, as well as xanthan gum, the stability of foliar fertilizer storage and transportation is ensured. Simultaneously, after dilution and foliar spraying, a stable liquid film can be quickly formed, enhancing the spreadability and wettability of the foliar fertilizer on the leaves, improving the penetration and absorption efficiency of nutrients and functional substances, and thus increasing the utilization efficiency of the fertilizer-infused foliar fertilizer product. Detailed Implementation

[0028] The present invention will be described in detail below with reference to specific steps. Unless otherwise specified, all parts in the present invention refer to parts by weight.

[0029] A method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat includes the following steps:

[0030] S1: Preparation of basic foliar fertilizer solution

[0031] Dissolve 12-15 parts of urea, 9-12 parts of potassium dihydrogen phosphate, and 0.4 parts of trace elements in 32.6 parts of deionized water, and adjust the pH to 6.0-6.5 to obtain the basic foliar fertilizer solution.

[0032] The trace elements include at least three of chelated manganese, chelated iron, chelated magnesium, and boron. Preferably, the trace elements are composed of amino acid chelated manganese, amino acid chelated iron, amino acid chelated magnesium, and boric acid in a mass ratio of 1:1:1:1, with a total mass fraction of 0.4 parts (i.e., 0.1 parts of each), which improves absorption and utilization.

[0033] S2: Preparation of plant-derived carbon-nitrogen solution

[0034] Chop wheat straw into 3cm pieces, add water to make the straw moisture content 20%, put it into a sealed high-pressure reaction vessel, heat it to 180℃, control the pressure at 1.5MPa, maintain it for 5 minutes, and quickly open the pressure relief valve to release the pressure to atmospheric pressure instantly, thus completing the steam explosion treatment.

[0035] The steam-exploded straw was crushed and passed through a 20-mesh sieve. Based on the dry weight of wheat straw, 40 U / g of cellulase and 20 U / g of xylanase were added. The pH was adjusted to 4.5-5, the temperature was controlled at 50℃, and the enzymatic hydrolysis reaction was carried out at 100 rpm for 30 h to obtain plant-derived polysaccharide solution.

[0036] Then, pure soybean powder was added to the plant-derived polysaccharide solution. The dry weight of the pure soybean powder was 1 / 10 of the dry weight of the wheat straw. The pH was adjusted to 8-8.5. Based on the dry weight of the wheat straw, 20 U / g of alkaline protease and 5 U / g of neutral protease were added. The temperature was controlled at 50℃, and the enzymatic hydrolysis reaction was carried out at 100 rpm for 6 hours. After the reaction was terminated, the pH was adjusted to 6-7, and the solution was concentrated to a solid content of 10% to obtain the plant-derived carbon-nitrogen solution.

[0037] S3: Preparation of potassium humate solution

[0038] Lignite with a humic acid content higher than 60% was crushed and passed through a 50-mesh sieve, and then ball-milled for 4 hours at 300 rpm using a dry ball mill with a ball-to-material ratio of 1:1. During ball milling, 10% potassium oxide by weight of the lignite powder was added to obtain 80-mesh lignite powder.

[0039] The lignite powder was oxidized at 70°C with a mixture of sulfuric acid and nitric acid in a volume ratio of 7:3 for 40 min, and then a 15% potassium hydroxide solution was added. The mixture was reacted at 60°C for 1 h to obtain a potassium humate reaction solution.

[0040] The reaction solution was precipitated in a settling tank, and then separated into solid and liquid components using a centrifuge to remove residue. Sulfuric acid was added to the separated solution to adjust the pH to 2, and polyacrylamide was added to precipitate and purify the fulvic acid. After membrane separation and desalting, a fulvic acid solution was obtained. Then, a 15% potassium hydroxide solution was added to the fulvic acid solution to adjust the pH to 7, and the solution was concentrated until the potassium fulvic acid content was 20%, thus obtaining the potassium fulvic acid solution.

[0041] S4: Preparation of photosynthetic bacteria agent

[0042] Prepare photosynthetic bacteria culture medium: Each liter of deionized water contains 3.5g sodium acetate, 0.8g ammonium chloride, 1.0g potassium dihydrogen phosphate, 0.5g magnesium sulfate, and 1.5g yeast extract. Adjust the pH to 7.0-7.5 with sodium bicarbonate. Preferably, add 0.005g Fe-EDTA and 0.055g peptone per liter of culture medium to improve the culture rate.

[0043] Thoroughly sterilize a transparent, sealable container with alcohol or sodium hypochlorite, add culture medium, then mix Rhodopseudomonas palustris and Rhodopseudomonas capsulatum at a live count ratio of 5:1, and quickly add the inoculum at a volume ratio of 2:8 to culture medium to avoid contamination by other microorganisms. Leave 5% space in the container for sealed culture.

[0044] Culture conditions: Ensure uniform illumination from all sides using LED artificial light or natural diffused light, with a light intensity of 3000 Lux, 24-hour light incubation at 30℃. Aerate intermittently twice daily for 20 minutes using an air pump with a sand filter, stirring twice daily. After 5 days of incubation, when the bacterial solution turns deep reddish-purple, has no odor, and the viable cell count is ≥50 × 10⁻⁶, the culture is considered complete. 8 The photosynthetic bacteria agent is obtained by measuring CFU / mL.

[0045] S5: Formulate Fertilizer-Bacterial Compound Foliar Fertilizer Stock Solution

[0046] Add 54-60 parts of the basic foliar fertilizer solution obtained in step S1 (composed of 12-15 parts urea, 9-12 parts potassium dihydrogen phosphate, 0.4 parts trace elements and 32.6 parts deionized water), 5 parts of the plant-derived carbon and nitrogen solution obtained in step S2, 5 parts of the potassium humate solution obtained in step S3, and 20 parts of the photosynthetic bacteria agent obtained in step S4 to deionized water containing 0.001% 28-homobrassinolide. Mix evenly at a stirring speed of 100 rpm to obtain the fertilizer-bacteria compound foliar fertilizer stock solution.

[0047] S6: Emulsification and Volume Adjustment

[0048] Under stirring at 500 rpm, add 0.05 parts of polyether-modified trisiloxane and 1 part of polyethylene glycol 2000 to the stock solution of the fertilizer-bacterial compound foliar fertilizer. After stirring for 10 min, increase the stirring speed to 2000 rpm and stir for 10 min, then reduce the stirring speed to 1000 rpm and add 0.3 parts of xanthan gum and stir for 5 min. The temperature is controlled at 35℃ throughout the process. Finally, add deionized water containing 0.001% 28-homobrassinolide to bring the total mass to 100 parts, thus obtaining the drought-resistant fertilizer-bacterial compound foliar fertilizer that can be stably stored for a long time.

[0049] An application of a drought-resistant microbial compound foliar fertilizer for wheat, wherein the drought-resistant microbial compound foliar fertilizer is applied as a foliar spray during the wheat's greening-up stage to the grain-filling stage. Under drought stress conditions, the drought-resistant microbial compound foliar fertilizer is applied as a foliar spray once every 10-15 days.

[0050] The present invention will be further explained and illustrated below with reference to embodiments. Obviously, the described embodiments are only a part of the embodiments, and not all of the embodiments. 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.

[0051] The differences in operating parameters of Examples 1-12 are summarized in Table 1. The preparation methods of each example are the same as the detailed preparation methods described above, with only the parameters being different.

[0052] Example 1

[0053] Fertilizer-grade raw materials: 12 parts urea, 9 parts potassium dihydrogen phosphate and 0.4 parts trace elements (chelated manganese, chelated iron and boron, mass ratio 1:1:1) were dissolved in 32.6 parts deionized water and the pH was adjusted to 6.0 to obtain the basic foliar fertilizer solution.

[0054] Plant-derived carbon-nitrogen solutions were prepared according to the S2 method, with the enzymatic hydrolysis of straw at pH 4.5 and the enzymatic hydrolysis of straw and pure soybean flour at pH 8.0. After terminating the enzymatic hydrolysis reaction, the pH was adjusted to 6.

[0055] Potassium humate solution was prepared according to method S3.

[0056] The photosynthetic bacteria agent was prepared according to method S4, wherein the pH of the photosynthetic bacteria culture medium was 7.0.

[0057] The above-mentioned basic foliar fertilizer solution (54 parts), 5 parts plant-derived carbon-nitrogen solution, 5 parts potassium humate solution, and 20 parts photosynthetic bacteria agent were sequentially added to deionized water containing 0.001% 28-homobrassinolide. After mixing evenly at 100 rpm, the fertilizer-bacterial compound foliar fertilizer stock solution was obtained. While stirring at 500 rpm, 0.05 parts polyether-modified trisiloxane and 1 part polyethylene glycol 2000 were added to the fertilizer-bacterial compound foliar fertilizer stock solution. After stirring for 10 min, the stirring speed was increased to 2000 rpm and stirred for 10 min, then the speed was reduced to 1000 rpm. Then, 0.3 parts xanthan gum were added and stirred for 5 min. The temperature was controlled at 35℃ throughout the emulsification process. Finally, deionized water containing 0.001% 28-homobrassinolide was added to bring the total mass to 100 parts (14.65 parts), thus obtaining the drought-resistant fertilizer-bacterial compound foliar fertilizer.

[0058] Example 2-12

[0059] The preparation steps of Examples 2-12 are the same as those of Example 1, except that the parameters are changed according to Table 1.

[0060] Table 1: Changes in operating parameters in Examples 1-12

[0061]

[0062] The following comparative examples are used to illustrate the beneficial effects of the key technical features of the present invention.

[0063] Comparative Example 1: The difference from Example 1 is that urea is replaced with an equal mass of ammonium nitrate, while other process parameters remain unchanged.

[0064] Comparative Example 2: The difference from Example 1 is that the plant-derived carbon-nitrogen solution was replaced with an amino acid solution of equal mass fraction and concentration, while other process parameters remained unchanged.

[0065] Comparative Example 3: The difference from Example 1 is that the potassium humate solution was replaced with an equal mass fraction and concentration of humic acid solution, while other process parameters remained unchanged.

[0066] Comparative Example 4: The difference from Example 1 is that the photosynthetic bacteria agent was replaced with an equal number of effective viable bacteria of Bacillus subtilis in equal mass fractions, while other process parameters remained unchanged.

[0067] Comparative Example 5: The difference from Example 7 is that no plant-derived carbon-nitrogen solution was added, while other process parameters remained unchanged.

[0068] Comparative Example 6: The difference from Example 7 is that potassium humate solution was not added, while other process parameters remained unchanged.

[0069] Comparative Example 7: The difference from Example 7 is that no photosynthetic bacteria agent was added, while other process parameters remained unchanged.

[0070] Comparative Example 8: The difference from Example 7 is that 28-homobrassinolide is not added, while other process parameters remain unchanged.

[0071] Comparative Example 9: The difference from Example 12 is that polyethylene glycol 2000 is not added, while other process parameters remain unchanged.

[0072] The following experimental examples are used to verify the beneficial effects of the drought-resistant fertilizer-bacterial compound foliar fertilizer of the present invention.

[0073] Experiment Example 1: Field Trial of Wheat in Irrigated Land

[0074] The drought-resistant fertilizer-bacterial compound foliar fertilizer products prepared in Examples 1-6 and Comparative Examples 1-4 were applied as foliar sprays during the jointing, booting, and grain-filling stages of wheat. The application rate was 150-200g per acre, diluted 300 times (manual spraying) or 30 times (aerial spraying) with water. Plant height, number of spikes, number of grains per spike, thousand-grain weight, and yield were recorded. The results are shown in Table 2. All data recorded were for a distance of 1000m. 2 10 1m experimental fields 2 Average value of data from survey points.

[0075] Table 2: Relevant data on the application of drought-resistant fertilizer-bacterial compound foliar fertilizers prepared in Examples 1-6 and Comparative Examples 1-4 during the tillering, booting, and early grain-filling stages of irrigated wheat.

[0076]

[0077] As shown in Table 2, the yield of wheat in Example 1 on irrigated land increased by 12.86%, 14.96%, 18.11%, and 15.74% compared with Comparative Examples 1-4, respectively, indicating that the drought-resistant fertilizer-bacterial compound foliar fertilizer prepared in this invention has significant advantages in increasing the yield composition and yield of wheat on irrigated land.

[0078] Comparative Example 1, replacing urea with ammonium nitrate, reduced the rate of nutrient absorption and moisture retention in leaves, resulting in poorer synergistic nutrient absorption. It also lacked the sustained, slow-release nitrogen supply characteristic of urea, leading to a decrease in yield composition and overall yield. Comparative Example 2, replacing plant-derived carbon-nitrogen solution with amino acid solution, only supplied the readily available nitrogen needed for wheat growth. The lack of small-molecule sugars and other carbon sources easily led to excessively high nitrogen content, affecting the absorption of other nutrients. Simultaneously, the carbon source supply improved wheat photosynthetic efficiency, especially under drought, low temperature, or low light conditions, alleviating "carbon hunger," increasing photosynthetic products, promoting growth, and increasing yield. Comparative Example 3, replacing potassium humate solution with fulvic acid solution, while both could improve wheat drought resistance, potassium humate foliar spraying was more effective. Containing functional groups and potassium, it had higher foliar absorption efficiency, improving photosynthesis, enhancing stress resistance, and significantly increasing thousand-grain weight and yield compared to fulvic acid solution. In Comparative Example 4, photosynthetic bacteria were replaced with Bacillus subtilis. The role of photosynthetic bacteria is to improve photosynthetic efficiency, especially under conditions of drought and low temperature. It can improve photosynthetic efficiency, promote dry matter accumulation, maintain carbon balance and chlorophyll function, and delay leaf senescence. Bacillus subtilis mainly improves wheat's disease resistance and can reduce the incidence of wheat sheath blight, Fusarium head blight and powdery mildew. Although it can also improve wheat's stress resistance, its effect is significantly lower than that of photosynthetic bacteria.

[0079] In summary, this invention introduces urea as a nitrogen source, which promotes absorption and slows down nitrogen release, resulting in better nitrogen supplementation, delayed senescence, and growth promotion. Simultaneously, the use of plant-derived carbon-nitrogen solution, potassium humate solution, and photosynthetic bacteria maximizes wheat photosynthetic efficiency and enhances its resistance to drought, low temperatures, and other adverse conditions, achieving carbon supplementation and stress resistance, improving photosynthetic efficiency, promoting dry matter accumulation, and ultimately achieving stress resistance, delayed senescence, and increased yield.

[0080] Experiment Example 2: Field Trial of Dryland Wheat

[0081] The drought-resistant fertilizer-bacterial compound foliar fertilizer products prepared in Examples 7-11 and Comparative Examples 5-8 were applied as foliar sprays to dryland wheat during the greening, booting, and early grain-filling stages. Plant height, number of spikes, number of grains per spike, thousand-grain weight, and yield were recorded. The results are shown in Table 3. All data are for a distance of 1000m. 2 10 1m experimental fields 2 Average value of data from survey points.

[0082] Table 3: Relevant data obtained from the foliar spraying of wheat drought-resistant fertilizer-bacterial compound foliar fertilizer prepared in Examples 7-11 and Comparative Examples 5-8 after application during the tillering, booting, and early grain-filling stages of dryland wheat.

[0083]

[0084] As shown in Table 3, the yield of Examples 7-11 on dryland wheat increased by 10.73%-22.61% compared with Comparative Examples 5-8, indicating that the drought-resistant fertilizer-bacterial compound foliar fertilizer prepared in this invention can effectively promote the composition and increase the yield of dryland wheat.

[0085] Compared to Example 7, Comparative Example 5 lacked plant-derived carbon and nitrogen solution, resulting in a decrease in the number of spikes, grains per spike, and thousand-grain weight of dryland wheat, leading to a significant drop in yield. This indicates that the addition of plant-derived carbon and nitrogen solution is beneficial for the rapid replenishment of carbon sources and available nitrogen through foliar application, especially under drought stress, as it can supplement the small-molecule carbon required for photosynthesis, improve photosynthetic efficiency and stress resistance, and achieve a significant increase in yield. Compared to Example 7, Comparative Example 6 lacked potassium humate solution, resulting in lower spike numbers, grains per spike, thousand-grain weight, and grain yield compared to Example 6. This demonstrates that potassium humate plays an important role in improving the drought resistance of dryland wheat, synergistically promoting nutrient absorption, and improving leaf photosynthesis. Compared with Example 7, Comparative Example 7 lacked photosynthetic bacteria, resulting in a significant decrease in plant height, number of spikes, number of grains per spike, thousand-grain weight, and grain yield. This fully demonstrates that adding photosynthetic bacteria to foliar fertilizer can effectively improve the photosynthetic efficiency of dryland wheat, especially under adverse conditions such as drought and low temperature, ensuring high photosynthetic efficiency under abiotic stress and significantly increasing the yield of dryland wheat. Compared with Example 7, Comparative Example 8 lacked 28-homobrassinolide, resulting in a certain degree of reduction in plant height, yield composition, and yield. This indicates that adding 28-homobrassinolide to the drought-resistant fertilizer-bacterial compound foliar fertilizer can promote crop growth and dry matter accumulation and transport, thereby increasing yield.

[0086] In summary, adding plant-derived carbon and nitrogen solution, potassium humate solution, photosynthetic bacteria, and 28-homobrassinolide to foliar fertilizer can compensate for the deficiency of ordinary foliar fertilizers in supplementing only the nitrogen, phosphorus, potassium, and trace elements required for wheat growth. Simultaneously, it supplements carbon sources, active substances, photosynthetic bacteria, and 28-homobrassinolide, which promote plant growth. This synergistic effect can enhance the resistance of dryland wheat to drought, low temperatures, and other adverse conditions during its growth period, promote nutrient absorption by leaves and roots, improve photosynthetic efficiency, increase photosynthetic products, improve yield composition, and ultimately achieve stress resistance and increased yield in dryland wheat.

[0087] Experimental Example 3: Effect Test of Additives

[0088] The drought-resistant fertilizer-bacterial compound foliar fertilizer products prepared in Example 12 and Comparative Example 9 were applied as foliar sprays to wheat in dryland areas during the greening, booting, and early grain-filling stages. Plant height, number of spikes, number of grains per spike, thousand-grain weight, and yield were recorded. The results are shown in Table 4. All recorded data are for a distance of 1000m. 2 10 1m experimental fields 2 Average value of data from survey points.

[0089] Table 4: Relevant data obtained from the investigation of the wheat drought-resistant fertilizer-bacterial compound foliar fertilizer prepared in Example 12 and Comparative Example 9 after foliar spraying during the tillering stage, booting stage and early grain filling stage of dryland wheat.

[0090]

[0091] As shown in Table 4, the plant height, number of spikes, number of grains per spike, thousand-grain weight, and yield of dryland wheat in Example 12 were all higher than those in Comparative Example 9, indicating that the drought-resistant fertilizer-bacterial compound foliar fertilizer prepared in the examples has certain advantages in improving the yield composition and increasing the yield of dryland wheat.

[0092] Compared to Example 12, Comparative Example 9 lacked Polyethanol 2000, resulting in a decrease in plant height, yield composition, and yield of dryland wheat. This indicates that adding Polyethanol 2000 as an adjuvant during the preparation of foliar fertilizer can effectively improve the physicochemical properties of the drought-resistant fertilizer-bacterial compound foliar fertilizer, enhance the adhesion and permeability of the foliar fertilizer solution on the surface of wheat leaves, promote the synergistic absorption of nutrient elements, and improve the stability of the foliar fertilizer and the uniformity of foliar spraying, thereby enhancing the drought resistance and yield increase of dryland wheat.

[0093] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A drought-resistant, microbial compound foliar fertilizer for wheat, characterized in that, This product is prepared from the following raw materials in parts by weight: 54-60 parts of basic foliar fertilizer solution, 5 parts of plant-derived carbon-nitrogen solution, 5 parts of potassium humate solution, 20 parts of photosynthetic bacteria agent, 0.05 parts of polyether-modified trisiloxane, 1 part of polyethylene glycol 2000, 0.3 parts of xanthan gum, and 8.65-14.65 parts of deionized water containing 0.001% 28-homobrassinolide; wherein the basic foliar fertilizer solution comprises 12-15 parts of urea, 9-12 parts of potassium dihydrogen phosphate, 0.4 parts of trace elements, and 32.6 parts of deionized water; the plant-derived carbon-nitrogen solution has a solids content of 10%; the potassium humate solution contains 20% potassium humate; and the photosynthetic bacteria agent has a viable count ≥50 × 10⁻⁶. 8 CFU / mL.

2. The method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 1, characterized in that, Includes the following steps: S1: Dissolve 12-15 parts of urea, 9-12 parts of potassium dihydrogen phosphate and 0.4 parts of trace elements in 32.6 parts of deionized water, adjust the pH to 6.0-6.5, and obtain the basic foliar fertilizer solution. S2: Wheat straw was steam-exploded and enzymatically hydrolyzed to obtain 5 portions of plant-derived carbon-nitrogen liquid; S3: The lignite was alkalized and purified to obtain 5 parts of potassium humate solution; S4: Expand and proliferate the photosynthetic bacteria strain to obtain 20 portions of photosynthetic bacteria agent; S5: Add the basic foliar fertilizer solution obtained in step S1, the plant-derived carbon and nitrogen solution obtained in step S2, the potassium humate solution obtained in step S3, and the photosynthetic bacteria agent obtained in step S4 to deionized water containing 0.001% of 28-homobrassinolide, mix evenly, and obtain the fertilizer-bacteria compound foliar fertilizer stock solution. S6: Add 0.05 parts of polyether-modified trisiloxane and 1 part of polyethylene glycol 2000 to the stock solution of the fertilizer-bacterial compound foliar fertilizer for emulsification, then add 0.3 parts of xanthan gum and stir. Finally, add deionized water containing 0.001% 28-homobrassinolide to bring the total mass to 100 parts, thus obtaining the drought-resistant fertilizer-bacterial compound foliar fertilizer.

3. The method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 2, characterized in that, Includes the following steps: In step S1, the trace elements include at least three of chelated manganese, chelated iron, chelated magnesium, and boron.

4. The method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 2, characterized in that, In step S2, the preparation method of the plant-derived carbon-nitrogen solution specifically includes: chopping wheat straw to 3cm, steam-exploding it, pulverizing it through a 20-mesh sieve, then adding 40 U / g cellulase and 20 U / g xylanase based on the dry weight of the wheat straw, adjusting the pH to 4.5-5, controlling the temperature at 50℃, and performing enzymatic hydrolysis at 100 rpm for 30 h to obtain a plant-derived polysaccharide solution; then adding pure soybean powder to the plant-derived polysaccharide solution, wherein the dry weight of the pure soybean powder is 1 / 10 of the dry weight of the wheat straw, adjusting the pH to 8-8.5, adding 20 U / g alkaline protease and 5 U / g neutral protease based on the dry weight of the wheat straw, controlling the temperature at 50℃, and performing enzymatic hydrolysis at 100 rpm for 6 h, terminating the reaction, adjusting the pH to 6-7, and concentrating to a solid content of 10% to obtain the plant-derived carbon-nitrogen solution.

5. The method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 2, characterized in that, In step S3, the preparation method of the potassium humate solution specifically includes: crushing lignite with a humic acid content higher than 60% through a 50-mesh sieve, ball milling, oxidizing it at 70°C with a mixed acid of sulfuric acid and nitric acid in a volume ratio of 7:3 for 40 min, then adding a 15% potassium hydroxide solution, reacting at 60°C for 1 h, the reaction solution undergoing sedimentation and solid-liquid separation, adjusting the pH of the separated solution to 2 to precipitate humic acid, purifying and desalting, adjusting the pH to 7 again, and concentrating it to a potassium humate content of 20% to obtain the potassium humate solution.

6. The method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 2, characterized in that, In step S4, the preparation method of the photosynthetic bacteria agent specifically includes: mixing *Rhodopseudomonas palustris* and *Rhodopseudomonas capsulatum* at a viable count ratio of 5:1, inoculating the mixture into a photosynthetic bacteria culture medium, and culturing it under sealed light for 5 days at a light intensity of 3000 Lux and a temperature of 30℃ to obtain a viable count ≥50×10⁻⁶. 8 CFU / mL photosynthetic bacteria agent; the photosynthetic bacteria culture medium consists of 3.5g sodium acetate, 0.8g ammonium chloride, 1.0g potassium dihydrogen phosphate, 0.5g magnesium sulfate, and 1.5g yeast extract per liter of deionized water, with a pH of 7.0-7.

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7. The method for preparing a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 2, characterized in that, In step S6, the temperature is controlled at 35°C throughout the emulsification process.

8. The application of the drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 1, characterized in that, The drought-resistant fertilizer-bacterial compound foliar fertilizer is used for foliar spraying during the wheat's greening-up stage to the grain-filling stage.

9. The application of a drought-resistant fertilizer-bacterial compound foliar fertilizer for wheat according to claim 8, characterized in that, Under drought stress, the drought-resistant fertilizer-bacterial compound foliar fertilizer shall be sprayed on the leaves once every 10-15 days.

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