Multifunctional water-soluble fertilizer as well as preparation method and application thereof

Abstract

The invention provides a multifunctional water-soluble fertilizer as well as a preparation method and application thereof, and belongs to the technical field of agricultural chemistry and fertilizers. The invention provides a multifunctional water-soluble fertilizer. The multifunctional water-soluble fertilizer is prepared from the following raw materials in parts by weight: 5-15 parts of potassium polysulfide, 10-20 parts of potassium silicate, 20-40 parts of sulfonated potassium humate and 5-10 parts of trace element chelate, the trace element chelate is a chelate formed by at least three of zinc, manganese, molybdenum, iron and copper and amino acid or EDTA (Ethylene Diamine Tetraacetic Acid). The multifunctional water-soluble fertilizer disclosed by the invention can effectively improve the pH value of rhizosphere soil, slowly release H2S gas signal molecules to excite the resistance of a crop system, remarkably promote root development, enhance the drought resistance and salt and alkali resistance of crops, improve the utilization rate of the fertilizer and realize yield increase and quality improvement.

Description

Technical Field

[0001] This invention belongs to the field of agricultural chemistry and fertilizer technology, and particularly relates to a multifunctional water-soluble fertilizer, its preparation method and application. Background Technology

[0002] Soil salinization and drought stress are key abiotic stressors hindering sustainable global agricultural development. Saline-alkali soils typically exhibit high pH levels, high sodium ion content, compacted soil structure, and poor permeability, severely inhibiting crop root development, hindering water and nutrient absorption, and ultimately leading to reduced yields or even crop failure. Meanwhile, drought further exacerbates the instability of agricultural production.

[0003] Currently, technical solutions for improving saline-alkali land and enhancing crop stress resistance mainly focus on the following aspects: applying chemical amendments, using organic materials and humic acids, applying silicon and potassium fertilizers, and applying stress-resistant water-soluble fertilizers. Among these, stress-resistant water-soluble fertilizers are water-soluble fertilizers used to enhance crop stress resistance. Existing stress-resistant water-soluble fertilizers mostly focus on adding biostimulants such as abscisic acid (ABA), betaine, alginic acid, and amino acids to induce crop resistance, or simply supplementing micronutrients. While these stress-resistant water-soluble fertilizers can alleviate stress symptoms to some extent, they often only address the symptoms, not the root cause, failing to simultaneously solve the fundamental problem of chemical barriers in saline-alkali soils. Furthermore, in high-pH saline-alkali soils, conventional micronutrients (such as iron, manganese, and zinc) are easily fixed in ineffective forms, leading to crop deficiencies, and even when added, they are difficult to absorb and utilize. Therefore, there is an urgent need for a water-soluble fertilizer that can integrate multiple functional mechanisms to effectively enhance the crop's own drought and salinity resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a multifunctional water-soluble fertilizer, its preparation method and application, which can significantly enhance the crop's drought and salt resistance.

[0005] This invention provides a multifunctional water-soluble fertilizer comprising the following raw materials in parts by weight: 5-15 parts potassium polysulfide, 10-20 parts potassium silicate, 20-40 parts potassium sulfonate, and 5-10 parts trace element chelates; wherein the trace element chelates are chelates formed by at least three of the elements zinc, manganese, molybdenum, iron, and copper with amino acids or EDTA.

[0006] Preferably, the multifunctional water-soluble fertilizer comprises the following raw materials in parts by weight: 8-12 parts potassium polysulfide, 12-18 parts potassium silicate, 25-35 parts potassium sulfonate, and 6-8 parts trace element chelate.

[0007] Preferably, the trace element chelate includes amino acid zinc, amino acid manganese, amino acid iron, and ammonium molybdate.

[0008] Preferably, the degree of polymerization n of sulfur in the potassium polysulfide is 2 to 4.

[0009] The present invention also provides a method for preparing the multifunctional water-soluble fertilizer described above, comprising the following steps: dissolving potassium sulfonate in water to obtain a mother liquor; dissolving potassium silicate and potassium polysulfide in the mother liquor in sequence, and then mixing them with a trace element chelate to obtain the multifunctional water-soluble fertilizer.

[0010] The present invention also provides the application of the multifunctional water-soluble fertilizer described in the above scheme or the multifunctional water-soluble fertilizer prepared by the preparation method in at least one of the following: 1) promoting crop root development; 2) enhancing crop drought resistance; 3) enhancing crop salt and alkali resistance; 4) soil improvement; 5) improving fertilizer utilization rate; 6) increasing crop yield; 7) improving crop quality.

[0011] The present invention also provides a method for applying the multifunctional water-soluble fertilizer described in the above-described scheme or the multifunctional water-soluble fertilizer prepared by the above preparation method, characterized by comprising the following steps: Dilute the multifunctional water-soluble fertilizer with water 300 to 800 times to obtain a diluted solution; apply the diluted solution to the roots of the crop.

[0012] Preferably, the application period includes after crop transplanting and seedling establishment, during critical growth periods, or when subjected to adverse abiotic stress.

[0013] Preferably, the abiotic stress includes drought stress and / or salinity stress.

[0014] Preferably, the application rate of the multifunctional water-soluble fertilizer is 3~10 kg / mu.

[0015] This invention provides a multifunctional water-soluble fertilizer comprising the following raw materials in parts by weight: 5-15 parts potassium polysulfide, 10-20 parts potassium silicate, 20-40 parts potassium sulfonate, and 5-10 parts trace element chelates; wherein the trace element chelates are chelates formed by at least three of zinc, manganese, molybdenum, iron, and copper with amino acids or EDTA. This invention is the first to utilize potassium polysulfide (K2S)... n Introducing potassium polysulfide as a core functional component into a multifunctional water-soluble fertilizer, its innovation extends far beyond simply providing potassium and sulfur nutrients. The hydrolysis and disproportionation reaction of potassium polysulfide after application to the soil is key to its functionality: S_n 2- + H2O → S n-1 2- + S 0 + 2OH - (Main pathways) and possible pathways: S_n 2- + 2H2O → H2S + S_{n-1} 2- + 2OH -(Secondary pathway). The hydrolysis and disproportionation reaction produces a triple effect: First, chemical modification: the reaction continuously generates OH-. - It can effectively and gently neutralize soil alkalinity and steadily reduce the rhizosphere pH; at the same time, it produces elemental sulfur (S). 0 With its small particle size and uniform distribution, it can serve as a slow-release sulfur source, continuing to generate sulfate ions (SO42-) after microbial oxidation. 2- First, the reaction involves the synergistic replacement of sodium ions to promote salt leaching. Second, the continuous regulation by gaseous signaling molecules: trace amounts of hydrogen sulfide (H2S) are continuously generated during the reaction. The low concentration of exogenous H2S can effectively induce a systemic stress response in crops, including significantly increasing the activity of antioxidant enzymes such as superoxide dismutase (SOD) to remove reactive oxygen species (ROS), maintaining cell membrane integrity (manifested as a decrease in MDA content), promoting root development (increasing root length and root surface area), and regulating stomatal opening and closing to enhance water retention capacity. This physiological regulation mediated by H2S is one of the core biochemical mechanisms by which this invention achieves the functions of "plant stress resistance" and "root promotion". Third, synergistic enhancement: the chemical soil-improving effect of potassium polysulfide in the multifunctional water-soluble fertilizer of this invention creates a good rhizosphere environment (such as a more suitable pH) for the function of potassium silicate and potassium sulfonate. The H2S signaling molecules generated by it, together with silicon, humic acid and trace elements, constitute a complex chemical-physiological synergistic effect. The superposition of multiple effects ultimately achieves a synergistic stress resistance and growth promotion effect far exceeding the sum of the effects of a single component.

[0016] Furthermore, the various raw materials in the multifunctional water-soluble fertilizer of this invention exhibit significant synergistic effects; the components are not simply mixed but rather mutually reinforcing. Potassium polysulfide improves the soil environment, laying the foundation for root growth; potassium silicate and potassium sulfonate synergistically form a protective film on the root surface, physically blocking stress; chelated micronutrients ensure nutrient supply under adverse conditions. Experimental data show that the absence of any core component significantly reduces the effectiveness.

[0017] In addition, the multifunctional water-soluble fertilizer of the present invention has multiple stress-resistant functions. It can not only significantly promote root development (significantly increase total root length and root surface area), but also physiologically enhance crop resistance (increase SOD activity and reduce MDA content), and effectively improve the rhizosphere soil environment (reduce pH and EC value). Its overall effect is far superior to conventional products on the market.

[0018] Furthermore, the multifunctional water-soluble fertilizer of this invention has wide applicability, especially suitable for crop planting in saline-alkali land and arid areas, and can be used for a variety of crops, such as tomatoes, corn, and cotton. The application method is simple and easy to promote. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This refers to the state after different raw materials are mixed. Figure 2 The image shows a comparison of maize growth under different treatments. From left to right, the images represent maize growth under the following treatments: water, blank (water + npk), comparative example 1, comparative example 2, comparative example 3, comparative example 4, example 2, and example 1. It is clear that the root system of example 1 is the most developed, while the root system of the blank control is sparse. Figure 3 The curves represent the kinetics of H2S release in soil; the x-axis represents time and the y-axis represents H2S concentration. The CK and T2 curves are always close to the x-axis. The T1 curve shows a low and broad peak with a peak value between 0.2 and 0.4 ppm, while the T3 curve shows a high and sharp peak with a peak value exceeding 3 ppm. Detailed Implementation

[0021] This invention provides a multifunctional water-soluble fertilizer comprising the following raw materials in parts by weight: 5-15 parts potassium polysulfide, 10-20 parts potassium silicate, 20-40 parts potassium sulfonate, and 5-10 parts trace element chelates; wherein the trace element chelates are chelates formed by at least three of the elements zinc, manganese, molybdenum, iron, and copper with amino acids or EDTA.

[0022] The multifunctional water-soluble fertilizer of this invention exhibits significant synergistic effects among its various raw materials. The components are not simply mixed, but rather mutually reinforcing. Potassium polysulfide improves the soil environment, laying the foundation for root growth; potassium silicate and potassium sulfonate synergistically form a protective film on the root surface, physically blocking stress; chelated micronutrients ensure nutrient supply under adverse conditions. Together, they promote crop root development and enhance crop drought and salt tolerance, which is of great strategic significance for ensuring national food security and improving agricultural resource utilization efficiency.

[0023] In one embodiment, the multifunctional water-soluble fertilizer is composed of the following raw materials in parts by weight: 5-15 parts potassium polysulfide, 10-20 parts potassium silicate, 20-40 parts potassium sulfonate, and 5-10 parts trace element chelates.

[0024] In one implementation method, the potassium polysulfide, potassium silicate, and potassium sulfonate are commercially available; the potassium polysulfide was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; the potassium silicate was purchased from Jinan Junteng Chemical Co., Ltd.; and the potassium sulfonate was purchased from Xinjiang Black Ecological Technology Co., Ltd.

[0025] In one embodiment, the multifunctional water-soluble fertilizer comprises the following raw materials in parts by weight: 8-12 parts potassium polysulfide, 12-18 parts potassium silicate, 25-35 parts potassium sulfonate, and 6-8 parts trace element chelate.

[0026] In one embodiment, the trace element chelate is composed of amino acid zinc, amino acid manganese, amino acid iron and ammonium molybdate.

[0027] In one embodiment, the amino acid zinc, amino acid manganese, amino acid iron, and ammonium molybdate are sourced from commercially available sources; the amino acid zinc was purchased from Hebei Pengyu Biotechnology Co., Ltd.; the amino acid manganese was purchased from Shandong Xinxiong Biotechnology Co., Ltd.; the amino acid iron was purchased from Hubei Haijia Biotechnology Co., Ltd.; and the ammonium molybdate was purchased from Shandong Yihong Chemical Co., Ltd.

[0028] In one embodiment, the degree of polymerization n of sulfur in the potassium polysulfide is 2 to 4.

[0029] In one embodiment, the raw material of the multifunctional water-soluble fertilizer also includes water.

[0030] In one embodiment of the present invention, the multifunctional water-soluble fertilizer is composed of the following raw materials in parts by weight: 10 parts potassium polysulfide, 15 parts potassium silicate (K2SiO3), 30 parts potassium sulfonate, and 7 parts trace element chelate; the trace element chelate is composed of the following components in parts by weight: 3 parts zinc amino acid, 2 parts manganese amino acid, 1.5 parts iron amino acid, and 0.5 parts ammonium molybdate.

[0031] In another embodiment of the present invention, the multifunctional water-soluble fertilizer is composed of the following raw materials in parts by weight: 8 parts potassium polysulfide, 18 parts potassium silicate, 25 parts potassium sulfonate and 8 parts trace element chelate; the trace element chelate is composed of the following components in parts by weight: 3 parts EDTA iron, 3 parts EDTA zinc, 1.5 parts borax and 0.5 parts ammonium molybdate.

[0032] In one embodiment, the water content in the multifunctional water-soluble fertilizer is 50% by mass.

[0033] In one embodiment, the pH value of the multifunctional water-soluble fertilizer is 10.5; the density of the multifunctional water-soluble fertilizer is 1.25 g / cm³. 3 The multifunctional water-soluble fertilizer has no precipitate and good water solubility.

[0034] This invention also provides a method for preparing the multifunctional water-soluble fertilizer described above, comprising the following steps: Potassium sulfonate was dissolved in water to obtain a mother liquor; potassium silicate and potassium polysulfide were dissolved in the mother liquor in sequence, and then mixed with trace element chelates to obtain a multifunctional water-soluble fertilizer.

[0035] The present invention first dissolves potassium sulfonate in water to obtain a mother liquor.

[0036] As one embodiment, the mass ratio of potassium sulfonate to water is 1:10~20; after the potassium sulfonate and water are mixed, they are stirred at 40~60°C until completely dissolved, and further stirred at 50°C until completely dissolved; the stirring time is 40 min.

[0037] After obtaining the mother liquor, the present invention dissolves potassium silicate and potassium polysulfide in the mother liquor in sequence, and then mixes them with trace element chelates to obtain a multifunctional water-soluble fertilizer.

[0038] As one implementation method, the potassium silicate and potassium polysulfide are dissolved in the mother liquor at room temperature.

[0039] As one implementation method, stirring is carried out during the dissolution or mixing of raw materials, and the mixing is carried out to ensure thorough mixing.

[0040] The preparation method of the present invention is simple and can ensure the stability of each component, especially potassium polysulfide.

[0041] After obtaining the multifunctional water-soluble fertilizer, the process also includes filtering and packaging the multifunctional water-soluble fertilizer in sequence; the filter screen used for filtration has a pore size of 100 mesh; the packaging uses an opaque dark-colored packaging barrel to prevent potassium polysulfide from decomposing when exposed to light.

[0042] The present invention also provides the application of the multifunctional water-soluble fertilizer described in the above scheme or the multifunctional water-soluble fertilizer prepared by the preparation method in at least one of the following: 1) promoting crop root development; 2) enhancing crop drought resistance; 3) enhancing crop salt and alkali resistance; 4) soil improvement; 5) improving fertilizer utilization rate; 6) increasing crop yield; 7) improving crop quality.

[0043] In one implementation, the soil improvement includes improving the pH of the rhizosphere soil; the improvement of the pH of the rhizosphere soil includes reducing the pH and / or EC value of the rhizosphere soil.

[0044] As one implementation, promoting crop root development includes increasing the total root length and / or root surface area of ​​the crop.

[0045] In one implementation, the multifunctional water-soluble fertilizer stimulates crop systemic resistance by slowly releasing H2S gaseous signaling molecules.

[0046] In one implementation, the enhancement of crop drought resistance and salt-alkali resistance is achieved by enhancing plant physiological resistance; enhancing plant physiological resistance includes increasing crop SOD activity and / or reducing MDA content in crops.

[0047] The multifunctional water-soluble fertilizer of this invention can effectively improve the pH of rhizosphere soil, slowly release H2S gaseous signaling molecules to stimulate crop system resistance, significantly promote root development, enhance crop drought and salt tolerance, and improve fertilizer utilization, thereby increasing yield and quality.

[0048] The present invention also provides an application method for the multifunctional water-soluble fertilizer described in the above scheme or the multifunctional water-soluble fertilizer prepared by the preparation method, comprising the following steps: diluting the multifunctional water-soluble fertilizer with water by 300 to 800 times to obtain a diluted solution; and applying the diluted solution to the roots of crops.

[0049] As one implementation method, the multifunctional water-soluble fertilizer is further diluted with water 500 to 600 times.

[0050] In one implementation method, the application period includes after crop transplanting and seedling establishment, during critical growth periods, or under abiotic stress; the abiotic stress includes drought stress and / or saline-alkali stress, further specifically saline-alkali stress. The above-mentioned application period represents the optimal timing for application, maximizing the stress-resistance effect of the multifunctional water-soluble fertilizer.

[0051] As one implementation method, the application rate of the multifunctional water-soluble fertilizer, before dilution, is 3~10 kg / mu.

[0052] As one implementation method, the diluted solution can be applied via drip irrigation, sprinkler irrigation, or root drenching. These methods are considered optimal for maximizing the stress-resistance effect of the multifunctional water-soluble fertilizer.

[0053] As one embodiment, suitable land for the application method includes saline-alkali land and / or arid land; the saline-alkali land includes slightly to moderately saline-alkali land. As one embodiment, the pH of the saline-alkali land is 8.1-8.6, more preferably 8.3-8.5, and even more preferably 8.4; the EC value of the saline-alkali land is 1.5-4.6 mS / cm, more preferably 3.2-3.6 mS / cm; and the organic matter content of the saline-alkali land is 10.3 g / kg.

[0054] In one embodiment, the crop includes at least one of tomato, corn, cotton and wheat; the corn variety includes Xianyu 335 or Zhengdan 958; the wheat variety includes Xindong 20; and the cotton variety includes Xinluzao 1.

[0055] To further illustrate the present invention, a multifunctional water-soluble fertilizer, its preparation method, and its application are described in detail below with reference to the accompanying drawings and embodiments. However, these descriptions should not be construed as limiting the scope of protection of the present invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All parts are by weight unless otherwise specified. All raw materials used in this invention, unless otherwise specified, are commercially available.

[0056] Example 1 1. Raw materials: The raw materials are weighed according to the following weight ratio: 10 parts potassium polysulfide (K2S4, n≈4), 15 parts potassium silicate (K2SiO3), 30 parts potassium sulfonate, and 7 parts trace element chelate, wherein the trace element chelate is composed of 3 parts zinc amino acid, 2 parts manganese amino acid, 1.5 parts iron amino acid, and 0.5 parts ammonium molybdate. 2. Preparation Method The steps are as follows: 1) In a stirred reactor, add an appropriate amount of deionized water (about 50% of the total mass of the final product), start stirring, slowly add sulfonated potassium humate, slowly raise the temperature to 50°C, and continue stirring for 40 minutes until it is completely dissolved, forming a dark brown homogeneous mother liquor.

[0057] 2) Stop heating and allow the mother liquor to cool naturally to 25°C. While stirring continuously, slowly add potassium silicate and stir until completely transparent. Then add potassium polysulfide and continue stirring for 30 minutes until completely dissolved.

[0058] 3) Finally, add the pre-mixed trace element chelate and stir thoroughly for 60 minutes to ensure the system is completely homogeneous.

[0059] 4) Filter the obtained liquid through a 100-mesh filter. The filtrate is the multifunctional water-soluble fertilizer product of this invention, with a pH value of approximately 10.5 and a density of 1.25 g / cm³. 3 It produces no precipitate and has good water solubility.

[0060] This invention also compares the states of different raw materials after mixing, see [link to relevant documentation]. Figure 1 The images, from left to right, are: "a mixture of potassium polysulfide and potassium silicate", "a mixture of potassium silicate and potassium sulfonate", "a mixture of potassium polysulfide and potassium sulfonate", "a mixture of potassium polysulfide with potassium silicate and potassium sulfonate in sequence", and "a mixture of potassium polysulfide with potassium silicate, potassium sulfonate and trace element chelates in sequence".

[0061] Example 2: Preparation of a multifunctional water-soluble fertilizer 1. Raw materials: The raw materials are weighed according to the following weight ratio: 8 parts potassium polysulfide, 18 parts potassium silicate, 25 parts potassium sulfonate and 8 parts trace element chelate, wherein the trace element chelate is composed of 3 parts EDTA iron, 3 parts EDTA zinc, 1.5 parts borax and 0.5 parts ammonium molybdate.

[0062] The preparation method is the same as in Example 1.

[0063] Comparative Example 1 Raw materials: Based on the raw materials in Example 1, potassium polysulfide is omitted, and an equal amount of potassium sulfate (calculated according to the potassium content) is used to supplement the potassium source.

[0064] The preparation method is the same as in Example 1.

[0065] Comparative Example 2 Raw materials: Based on the raw materials in Example 1, potassium silicate is omitted, and an equal amount of potassium sulfate is used to supplement the potassium source.

[0066] The preparation method is the same as in Example 1.

[0067] Comparative Example 3 Raw materials: Based on the raw materials in Example 1, sulfonated potassium humate is omitted and replaced with an equal amount of ordinary potassium humate.

[0068] The preparation method is the same as in Example 1.

[0069] Comparative Example 4 Use commercially available stress-resistant water-soluble fertilizers, and commercially available alginic acid-based macro-element water-soluble fertilizers (N-P2O5-K2O: 15-15-30, containing seaweed extract) that claim to have stress-resistant functions, according to their recommended concentrations.

[0070] Experiment Example 1: Comparison of Accelerated Thermal Storage Stability of Water-Soluble Fertilizers with Different Formulas This experiment aims to systematically evaluate the impact of key components such as potassium polysulfide, potassium silicate, and different types of potassium humate on the thermal stability of water-soluble fertilizer systems through accelerated thermal storage stability testing. By comparing the appearance, pH value, potassium polysulfide decomposition rate, and water-insoluble matter content of different formulations, the role of each component is clarified, providing a basis for optimizing formulations and improving product storage stability.

[0071] 1. Materials Main raw material: Potassium polysulfide (K2S) n Potassium silicate (K2SiO3), sulfonated potassium humate (industrial grade), ordinary potassium humate (industrial grade), and macronutrient fertilizers (such as potassium nitrate, potassium dihydrogen phosphate, etc., determined according to the basic formula). Control sample: Commercially available seaweed-based water-soluble macronutrient fertilizer products (Comparative Example 4).

[0072] Equipment and instruments: electronic balance, constant temperature water bath or oven, stoppered colorimetric tubes or conical flasks (50-100 mL), pH meter, centrifuge, vacuum filtration device, constant temperature drying oven.

[0073] 2. Sample Preparation Formulation Design: Based on the research objectives, each component was accurately weighed, and the following 5 groups of samples were prepared: Example 1: Basic Formulation (containing K2S) n (K2SiO3, potassium sulfonate, and macroelements). Example 2: Basic formulation with adjusted proportions of some additives (used to examine the effect of fine-tuning the formulation). Comparative Example 1: Lacking the core component potassium polysulfide (K2SiO3, potassium sulfonate, and macroelements). n The formula is as follows: Example 1: Formula lacking the key stabilizer potassium silicate (K2SiO3). Example 2: Formula using ordinary potassium humate instead of sulfonated potassium humate. Dissolution and volume adjustment: Add each ingredient to deionized water, stir at room temperature until completely dissolved or a homogeneous and stable liquid is formed, and then bring the volume to the same level to obtain the initial water-soluble fertilizer solution.

[0074] 3. Accelerated thermal storage stability testing Test conditions: Following industry standards, the high-temperature accelerated aging method was used. The sample solutions from each treatment group were dispensed into clean, dry, stoppered glass containers, ensuring consistent filling volume (approximately 2 / 3 full). These were then placed in a constant-temperature environment and stored at (54±2)℃ in the dark for 14 days.

[0075] Observation and recording: The following indicators were measured and observed before the start of the experiment (day 0) and after the end of the experiment (day 14).

[0076] 4. Evaluation Indicators and Testing Methods Appearance: Under natural light or standard light source, visually inspect and record whether the sample solution exhibits precipitation, layering, turbidity, discoloration, or flocculent formation.

[0077] pH change (ΔpH): Using a calibrated precision pH meter, the pH values ​​of the samples were measured before and after heat storage. ΔpH = pH(after) - pH(before), and the change was recorded.

[0078] Relative decomposition rate of potassium polysulfide: For those containing K2S n The effective sulfur (or potassium polysulfide) content in the samples (Examples 1, 2, Comparative Examples 2, 3) before and after thermal storage was determined by chemical titration (such as iodometric titration) or spectrometry.

[0079] Relative decomposition rate (%) = [(initial content - content after thermal storage) / initial content] × 100%.

[0080] Comparative Examples 1 and 4 are either not included or have unclear K2S. n Content, this item is marked as "—".

[0081] Water-insoluble matter content: Take a certain amount (e.g., 50g) of the sample solution after heat storage, and use a filter membrane of known weight (pore size approximately 0.45μm) for vacuum filtration, or collect the insoluble matter by centrifugation. Wash the insoluble matter thoroughly with deionized water, and dry it together with the filter membrane at (105±2)℃ to constant weight.

[0082] Water-insoluble matter content (%) = [(insoluble matter and constant weight of filter membrane - weight of filter membrane) / mass of sample solution] × 100%.

[0083] Comprehensive stability evaluation: Based on the test results of the above four indicators, especially the two key indicators of appearance change and potassium polysulfide decomposition rate, the storage stability of each treatment group is rated as "excellent, good, medium and poor".

[0084] 5. Data Recording and Analysis All measurement results are summarized in Table 1. By comparing and analyzing the specific effects of each component (especially K2SiO3 and different potassium humates) on the thermal stability of the water-soluble fertilizer system, experimental conclusions are drawn.

[0085] 6. The results are shown in Table 1. The results show that Example 1 exhibits the best overall stability. Comparative Example 2 (missing data) Potassium silicate showed the worst stability, indicating that it plays a crucial role in maintaining system stability and preventing the rapid decomposition of potassium polysulfide. Comparative Example 3 demonstrates that sulfonated potassium humate is superior to ordinary potassium humate in terms of solubility and system compatibility.

[0086] Table 1. Comparison of accelerated thermal storage stability of water-soluble fertilizers with different formulations (54±2)℃, 14 days)

[0087] Stability test of the multifunctional water-soluble fertilizer prepared in Example 2 of Example 1 To verify the physical and chemical stability of the multifunctional water-soluble fertilizer prepared in Example 1 of this invention under long-term storage and high-temperature conditions, and to evaluate its shelf life.

[0088] 1. Test method: Referring to the "Fertilizer Labeling Content and Requirements" and general chemical product stability testing methods, the stability was investigated using room temperature storage tests and accelerated thermal storage tests.

[0089] Room temperature storage test: Store the sample in a sealed container in a cool, dry place (ambient temperature 5~30℃), and observe and test it regularly.

[0090] Accelerated thermal storage test (high temperature stress test): The sample was sealed and placed in a constant temperature incubator and stored at (54±2)℃ for 14 days. After the thermal storage was completed, it was cooled to room temperature, and various indicators were observed and tested. This condition can simulate the effect of long-term storage.

[0091] 2. Detection indicators and results: Tests were conducted at the start of the test (day 0), on day 90 and day 180 after storage at room temperature, and after the end of the heat storage test. The results are recorded in Table 2.

[0092] Table 2. Stability test results of the multifunctional water-soluble fertilizer prepared in Example 1

[0093] Note: The relative decomposition rate of potassium polysulfide was calculated by measuring the change in effective sulfur content before and after thermal storage.

[0094] 3. Experimental Conclusions: The multifunctional water-soluble fertilizer prepared in Example 1 of this invention remained stable in appearance, pH value, water-insoluble matter content, and main active ingredients during a 180-day storage period at room temperature, without significant changes. Under the harsh conditions of accelerated heat storage at (54±2)℃ for 14 days, although the product underwent slight changes (such as a slight increase in pH value and a small amount of decomposition of potassium polysulfide), all key indicators remained within controllable and acceptable ranges, and no precipitation, crystallization, stratification, or significant degradation of active ingredients occurred. This indicates that the formulation of the product of this invention is scientific, the preparation process is reasonable, it has good chemical stability and a long shelf life, and can meet the requirements of commercial production and storage.

[0095] The effect of an unreasonable preparation sequence on stability in Comparative Example 5 1. The raw materials are the same as in Example 1.

[0096] 2. Preparation Method: At room temperature, potassium polysulfide and potassium silicate were first dissolved together in water. The solution quickly turned into a milky white turbid liquid with a slight sulfurous odor (H2S escaping). Then, potassium sulfonate was added. Despite vigorous stirring, the system could not be restored to clarity, and a small amount of yellow suspended matter (elemental sulfur) remained at the bottom. The resulting turbid liquid was subjected to an accelerated heat storage test at (54±2)℃ for 7 days. After heat storage, the solution showed severe stratification, with a large amount of yellow precipitate appearing at the bottom. Testing indicated that the decomposition rate of potassium polysulfide exceeded 40%, and the product was ineffective. 3. Conclusion: Comparison of Example 5 and Example 1 demonstrates that changing the order of addition, adding highly alkaline potassium polysulfide and potassium silicate first, leads to excessively high local pH, causing rapid hydrolysis and disproportionation of potassium polysulfide, generating elemental sulfur precipitate and H2S gas, resulting in loss of effective components and damage to the physical stability of the product. This indirectly verifies the crucial role of the process in Example 1 of this invention, in maintaining product stability, which involves first dissolving potassium sulfonate to form a buffer mother liquor, cooling it, and then sequentially adding other components.

[0097] Experiment Example 3: A comprehensive comparative experiment on the effects of different formulations of multifunctional water-soluble fertilizers on the growth, physiology, and rhizosphere soil of maize seedlings under salt stress. 1. The purpose of the experiment is to verify and compare the effects of different embodiments of the present invention (Examples 1 and 2) on the growth promotion, stress resistance and soil improvement of maize seedlings under salt stress conditions with comparative examples (Comparative Examples 1 to 3) lacking core components or using alternative materials, and commercial products (Comparative Example 4), so as to systematically evaluate the superiority, synergy and indispensability of the formulation of the present invention and the core components.

[0098] 2. Test materials The tested maize variety was Xianyu 335. The tested fertilizers were the multifunctional water-soluble fertilizers prepared in Examples 1 and 2, as well as the formulations of Comparative Example 1 (potassium polysulfide deficient), Comparative Example 2 (potassium silicate deficient), and Comparative Example 3 (common potassium humate). Comparative Example 4 was a commercially available humic acid stress-resistant water-soluble fertilizer. The tested soil was collected from slightly saline-alkali farmland (initial pH=8.3, EC=1.2 mS / cm), air-dried, sieved, and then placed in plastic basins (3 kg per basin).

[0099] 3. Experimental Design Seven treatments were set up: (1) CK, blank control: watering with an equal amount of water; (2) NPK (conventional nitrogen, phosphorus and potassium fertilization); (3) Example 1 (T1): watering with a 500-fold diluted solution of the multifunctional water-soluble fertilizer prepared in Example 1 + an equal amount of NPK; (4) Example 2 (T2): watering with a 500-fold diluted solution of the multifunctional water-soluble fertilizer prepared in Example 2 + an equal amount of NPK; (5) Comparative Example 1 (T3, potassium polysulfide deficient): watering with a control without potassium polysulfide (potassium source supplemented with an equal amount of potassium sulfate). (6) Comparative Example 2 (T4, potassium silicate deficient): Irrigated with a 500-fold diluted solution of control fertilizer (with potassium sulfate supplemented as a potassium source) and an equal amount of NPK; (7) Comparative Example 3 (T5, common potassium humate): Irrigated with a 500-fold diluted solution of control fertilizer (with common potassium humate replacing sulfonated potassium humate) and an equal amount of NPK; (8) Comparative Example 4 (T6, commercially available product): Irrigated with a 500-fold diluted solution of a commercially available humic acid stress-resistant water-soluble fertilizer. Each treatment was repeated 6 times. After sowing, when the corn seedlings grew to the three-leaf stage, all treatments were irrigated with 100 mL of 100 mmol / L NaCl solution to simulate salt stress. 24 h later, the first fertilization treatment was carried out, with 100 mL of the corresponding fertilizer solution irrigated per pot. Thereafter, irrigation was carried out once every 7 days for a total of two times.

[0100] 4. Measurement Items and Methods Measurements were taken 14 days after the last fertilization: Root morphology: Roots were washed and total root length and root surface area were analyzed using a root scanner and analysis software (such as WinRHIZO). Physiological indicators: Fresh leaves were collected to measure chlorophyll content (SPAD value), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content. Soil indicators: Rhizosphere soil was collected to measure pH and electrical conductivity (EC value).

[0101] 5. Test Results In this comprehensive comparative experiment (see Table 3), different treatments had a significant impact on the growth, physiology, and rhizosphere environment of maize seedlings under salt stress.

[0102] Regarding root development, all fertilizer treatments showed some root-promoting effects, but the differences in effectiveness were significant. The treatment in Example 1 showed the most outstanding effect, with a total root length (658.7 cm) and root surface area (125.8 cm²). 2 Both were significantly higher than the blank control ( P <0.01), with increases of 71.0% and 83.6%, respectively. The effect of treatment in Example 2 was second best, with total root length and root surface area significantly superior to other treatments except Example 1 ( P <0.05). It is worth noting that Comparative Example 1 (deficient in potassium polysulfide) and the treatment had the weakest effect. Although its root index was significantly higher than the blank control, it was significantly lower than that of Example 1, Example 2 and Comparative Example 4 (commercially available product). P <0.05). This directly indicates that the absence of the core component potassium polysulfide severely weakens the root-promoting ability of the product. The root-promoting effects of Comparative Example 2 (potassium silicate deficiency) and Comparative Example 3 (common potassium humate) were also significantly less than those of the two examples, further demonstrating the necessity of each core component in the complete formulation system.

[0103] Regarding plant physiological resistance, the treatment in Example 1 exhibited the strongest overall stress resistance. Its chlorophyll content (41.5 SPAD) and SOD activity (298.6 U / g FW) were both significantly higher than the blank control. P <0.01, and significantly higher than all other treatments ( P <0.05. The MDA content, a key indicator of oxidative damage, was lowest in the treatment of Example 1 (8.91 pmol / g FW), significantly lower than the blank control ( P The SOD activity was <0.01%, and significantly lower than other treatments (P<0.05). This indicates that the core formulation of this invention can most effectively maintain leaf photosynthetic function, activate the antioxidant system, and reduce cell membrane damage. Comparative Example 1 (potassium polysulfide deficient) showed the lowest SOD activity and the highest MDA content, further highlighting the key role of potassium polysulfide in stimulating system resistance.

[0104] In terms of rhizosphere soil improvement, the treatment in Example 1 also performed best, with its rhizosphere soil pH (7.68) and EC value (1.41 mS / cm) being significantly lower than the blank control. P <0.01), and the improvement effect is significantly better than all other treatments ( P <0.05). Crucially, Comparative Example 1 (deficient in potassium polysulfide) showed no significant difference from the control in reducing soil pH and EC values. P >0.05), which strongly confirms from the opposite perspective that potassium polysulfide is an indispensable core functional component for achieving soil chemical improvement (neutralizing alkalinity and reducing salinity).

[0105] Comprehensive analysis shows that the optimal formulation of this invention, represented by Example 1, can achieve comprehensive regulation and protection of maize seedlings under salt stress by simultaneously and significantly promoting root development, enhancing plant physiological resistance, and improving the rhizosphere soil environment. Its overall effect is significantly better than that of Example 2, the comparative examples of missing components, and commercially available similar products. Comparative Example 1 (lacking potassium polysulfide) performed the worst in all key indicators, strongly demonstrating that potassium polysulfide plays an irreplaceable core role in the formulation system of this invention. Its dual functions of slow-release H2S gaseous signaling molecules and direct chemical soil improvement are key to generating synergistic effects.

[0106] Table 3. Effects of different salt stress treatments on maize seedling growth, physiology, and rhizosphere soil.

[0107] 6. Experimental Conclusions Example 1 significantly outperformed all other treatments in all key indicators, demonstrating the comprehensive efficacy of its optimal formulation. Comparative Example 1 (potassium polysulfide deficiency) showed the worst results in all growth-promoting and physiological indicators, and its soil improvement effect was no different from the control, directly proving that potassium polysulfide is the core of chemical soil improvement and the activation of systemic stress resistance, and its role cannot be replaced by simple potassium sources such as potassium sulfate. Comparative Example 2 (potassium silicate deficiency): Root development and physiological resistance indicators decreased significantly, indicating that potassium silicate is indispensable in the construction of physical barriers and synergistic enhancement of plant resistance. Comparative Example 3 (common potassium humate) showed better results than Comparative Examples 1 and 2, but significantly worse than Example 1, demonstrating that sulfonated potassium humate has unique advantages in solubility, activity, and synergy with other components (especially potassium polysulfide).

[0108] Experiment Example 4: Field Trial of Increased Maize Yield in Saline-Alkali Land To verify the effects of the multifunctional water-soluble fertilizer prepared in Example 1 of this invention on the agronomic traits and yield of maize under actual saline-alkali conditions in the field.

[0109] 1. Site Overview: The experiment was conducted in Honghai Village 9, Bachu County, Xinjiang, in moderately saline-alkali soil. Basic soil properties: pH 8.5, EC 3.6 mS / cm, organic matter content 10.3 g / kg. Tested maize variety: Zhengdan 958.

[0110] 2. Experimental Design Set up 3 processes: (1) Control (CK): Conventional fertilization (base fertilizer + top dressing of urea) and watering with the same amount of water.

[0111] (2) Treatment (T): Conventional fertilization + the multifunctional water-soluble fertilizer of the present invention (the multifunctional water-soluble fertilizer prepared in Example 1).

[0112] A randomized block design was used, with each treatment repeated three times and each cell area being 30 m². 2 Application method: During the corn jointing and tasseling stages, apply the multifunctional water-soluble fertilizer of this invention at a dosage of 5 kg per acre, diluted 500 times, and then combined with the drip irrigation system. The control group was irrigated with the same amount of clean water during the same period.

[0113] 3. Measurement items and methods: After the rice matures, the middle two rows of each plot are harvested for yield calculation, and yield components such as ear length, tip barrenness length, number of rows per ear, number of grains per row, and thousand-grain weight are measured.

[0114] 4. Test Results: The results are shown in Table 4.

[0115] Table 4. Effects of the multifunctional water-soluble fertilizer prepared in Example 1 of this invention on maize yield and its constituent factors in saline-alkali land.

[0116] Note: Different letters after the data in the same column indicate that the differences between treatments are significant at the p<0.05 level.

[0117] 5. Experimental Conclusions Field trial results showed that on moderately saline-alkali land, the application of the multifunctional water-soluble fertilizer prepared in Example 1 of this invention, in addition to conventional fertilization, significantly improved the yield components of maize: effectively increasing ear length and diameter (manifested as an increase in the number of rows per ear), reducing tip barrenness caused by salt stress, and significantly increasing the number of kernels per row and the thousand-kernel weight. This indicates that the multifunctional water-soluble fertilizer prepared in Example 1 of this invention promotes root development and enhances stress resistance, ensuring the fullness of maize grain filling in the later stages. Ultimately, the yield of treatment T reached 587.2 kg / mu, a significant increase of 20.9% compared to the control (CK), demonstrating significant economic benefits. This experiment fully demonstrates the application value and yield-increasing potential of the multifunctional water-soluble fertilizer prepared in Example 1 of this invention in real saline-alkali land environments.

[0118] Experiment Example 5: Application Experiment of Wheat Drought Resistance This study verifies the effects of the multifunctional water-soluble fertilizer prepared in Example 1 of the present invention on wheat root growth, physiological resistance and yield under drought stress, and demonstrates its application potential in arid regions.

[0119] 1. Test materials The wheat variety tested was 'Xindong 20'.

[0120] Fertilizer tested: Multifunctional water-soluble fertilizer.

[0121] Soil tested: Farmland soil collected from Qitai Wheat Experimental Station of Xinjiang Academy of Agricultural Sciences (initial pH=8.1, EC=1.5 mS / cm).

[0122] Experimental design: Pot experiment, with 4 kg of soil in each pot.

[0123] 2. The experimental design includes four treatments: (1) CK (blank control): conventional irrigation, no fertilizer added.

[0124] (2) T1 (Fertilizer of the present invention): Apply a 500-fold diluted solution of the multifunctional water-soluble fertilizer prepared in Example 1.

[0125] (3) T2 (commercially available drought-resistant fertilizer): Apply commercially available humic acid-based drought-resistant water-soluble fertilizer (at the recommended concentration).

[0126] (4) T3 (lacking potassium polysulfide): Apply control fertilizer that does not contain potassium polysulfide (formula same as comparative example 1).

[0127] Each treatment was repeated 8 times. Drought stress treatment: Irrigation was stopped for 7 days during the wheat jointing stage to reduce soil moisture content to 40% of field capacity, simulating moderate drought. Fertilization method: On the 3rd day after the start of drought stress, 200 mL of the corresponding fertilizer solution was applied to each pot, once every 7 days, for a total of 2 times.

[0128] 3. Measurement Indicators Root morphology: total root length, root surface area.

[0129] Physiological indicators: chlorophyll content (SPAD), superoxide dismutase (SOD) activity, malondialdehyde (MDA) content.

[0130] Yield indicators: number of ears per pot, number of grains per ear, and weight of 1,000 grains.

[0131] 4. The experimental results are shown in Table 5 (mean ± standard deviation, different letters in the same column indicate different values). p (The difference was statistically significant at levels <0.05).

[0132] Table 5 Wheat growth status and yield

[0133] 5. Conclusion Under drought stress, the multifunctional water-soluble fertilizer (T1) prepared in Example 1 of this invention significantly promotes wheat root development, increases antioxidant enzyme activity, reduces membrane lipid peroxidation damage, and increases yield. Compared with commercially available products, this invention performs better in drought resistance, and potassium polysulfide is a key functional component.

[0134] Experimental Example 6: Field Trial of Cotton's Salt-Alkali Resistance To verify the effects of the multifunctional water-soluble fertilizer prepared in Example 1 of this invention on cotton growth, fiber quality, and soil improvement in saline-alkali cotton fields.

[0135] 1. Overview of the test site The experiment was conducted in moderately saline-alkali soil in Aksu region of Xinjiang (soil pH=8.6, EC=3.2 mS / cm). The cotton variety tested was 'Xinluzao No. 1'.

[0136] 2. The experimental design includes three treatments: (1) CK: Conventional fertilization (base fertilizer + top dressing), irrigation with clean water.

[0137] (2) T1: Conventional fertilization + multifunctional water-soluble fertilizer prepared in Example 1 of this invention (Product of Example 1).

[0138] (3) T2: Conventional fertilization + commercially available salt-alkali resistant water-soluble fertilizer (humic acid type).

[0139] Randomized block design, with 3 replicates per treatment and a cell size of 40 m². 2 .

[0140] Application method: Apply once each during the cotton budding stage and the boll-forming stage, using 5 kg per acre per application, diluted 500 times and then drip-irrigated.

[0141] 3. Measurement Indicators Agronomic traits: plant height, number of bolls, fiber length, lint percentage.

[0142] Soil parameters: rhizosphere soil pH and EC.

[0143] Production: Seed cotton production.

[0144] 4. The experimental results are shown in Table 5 (mean ± standard deviation, different letters in the same column indicate significant differences at the p<0.05 level).

[0145] Table 6 Cotton quality and yield and soil physical and chemical indicators

[0146] 5. Conclusion The multifunctional water-soluble fertilizer prepared in Example 1 of this invention can significantly improve the growth of cotton in saline-alkali land, increase boll number, fiber quality and yield, and effectively reduce the pH and EC value of rhizosphere soil, with better results than commercially available products.

[0147] Experimental Example 7: Study on the kinetics and concentration effects of potassium polysulfide releasing H2S in soil. The purpose of this invention is to verify whether potassium polysulfide, the core component of this invention, can continuously and slowly release low concentrations of hydrogen sulfide (H2S) after being applied to saline-alkali soil, and to clarify its release dynamics and peak concentration, so as to prove its mechanism of action and ensure that its concentration is within the safe threshold for promoting growth and stress resistance.

[0148] 1. Test Methods Test soil: Same as the application effect verification experiment, collected from slightly saline-alkali farmland soil (pH=8.3, EC=1.8mS / cm).

[0149] Experimental design: Four treatments were set up: (1) T1 (treatment of the present invention): Weigh 500g of air-dried and sieved soil sample, and add the multifunctional water-soluble fertilizer (containing potassium polysulfide) prepared in Example 1 of the present invention, which is equivalent to the recommended dosage in Example 1 (diluted 600 times, 500mL for potting).

[0150] (2) T2 (Potassium polysulfide-free control): Weigh 500g of soil sample and add an equal amount of fertilizer without potassium polysulfide (formula same as comparative example 1).

[0151] (3) T3 (high dose of potassium polysulfide treatment): Weigh 500g of soil sample and add 5 times the dose of potassium polysulfide of T1 (to verify the high concentration inhibition effect).

[0152] (4) CK (blank control): Weigh 500g of soil sample and add an equal amount of water.

[0153] Each treatment was replicated four times. After the fertilizer was mixed with the soil, the soil moisture content was adjusted to 70% of field capacity and then placed into a sealable gas sampling culture bottle.

[0154] H2S gas collection and detection: In-situ monitoring was performed using a static chamber-gas chromatography method or a portable hydrogen sulfide gas detector. Gas samples were collected from the headspace of the culture flasks using a gas sampler at 1, 3, 6, 12, 24, 48, 72, 120, and 168 hours (1–7 days) after fertilization. Analysis was performed using a gas chromatograph equipped with a flame photometric detector (FPD), with quantification using the external standard method. Alternatively, a calibrated portable H2S detector was used for direct reading. Plant biomass validation: After the culture experiment, maize seeds were sown in each treatment pot, and the early seedling growth (plant height, root length) was observed to visually verify the effects of different H2S release levels on the plants.

[0155] 2. Experimental Results and Analysis: The test results are shown in Table 7 and Figure 3 .

[0156] Table 7 Dynamic changes in H2S gas concentration in soil under different treatments (unit: ppm, X±SD, n=4)

[0157] Note: Different lowercase letters after the data in the same row indicate significant differences at the P<0.05 level. 1 ppm ≈ 1.4 mg / m³ 3 .

[0158] Results analysis: After application to the soil, the H2S concentration in the T1 treatment (of this invention) gradually increased, reaching a peak of 0.82–0.95 ppm at 24–48 h, and then slowly decreased, reaching a low level by 168 h (7 days). This indicates that the hydrolysis and disproportionation reaction of potassium polysulfide is a slow-release, controllable process that continuously provides H2S signaling molecules, rather than an instantaneous burst. The peak H2S concentration released by the treatment (T1) of this invention remained below 1.0 ppm. Numerous plant physiological studies have shown that H2S concentrations below 1–2 ppm can effectively activate the plant's antioxidant system and growth-promoting pathways without any toxic effects. The data from this invention fully comply with this safety threshold range.

[0159] The H2S concentration in the T2 (potassium polysulfide-free) treatment was not significantly different from that in the control (CK) treatment, and was almost undetectable. This directly proves that the H2S detected in the soil originated entirely from the potassium polysulfide added in this invention, and not from other components or the soil itself. The T3 (5 times higher dose) treatment showed an extremely high H2S concentration exceeding 3.57 ppm. At this concentration, the germination rate of subsequently sown tomato seeds was significantly reduced, seedling roots became noticeably blackened and withered, and growth was strongly inhibited. This conversely demonstrates the crucial importance of precisely controlling the amount of potassium polysulfide used, and that the formulation design of this invention ensures that it is within the optimal low concentration range.

[0160] 3. Conclusion: The potassium polysulfide component in the multifunctional water-soluble fertilizer prepared in Example 1 of this invention can slowly release low concentrations of H2S gas in saline-alkali soil. Its release kinetics exhibit a slow rise followed by a steady decline, with the effect lasting for several days. The peak H2S concentration throughout the release process remains stable below 1.0 ppm, a concentration widely recognized as a safe and effective window for promoting plant growth and stress resistance, completely avoiding the risk of high-concentration toxicity. This data, along with the physiological effects observed in the main example such as increased SOD activity, decreased MDA content, and root promotion, forms a complete chain of evidence, strongly supporting the core mechanism of action of this invention—"H2S gas signaling molecule-mediated physiological regulation"—significantly enhancing the scientific rigor and inventiveness of the invention.

[0161] Experimental Example 8: Long-term application and its effect on soil properties The long-term improvement effect of the multifunctional water-soluble fertilizer prepared in Example 1 of this invention on saline-alkali soil and the stability of crop yield were evaluated after two consecutive years of application.

[0162] 1. Experimental Design A field experiment was conducted in saline-alkali land (initial pH=8.4, EC=4.6 mS / cm) in Jiashi County, Kashgar Prefecture, Xinjiang.

[0163] Crop rotation: maize-wheat. Two treatments were set up: (1) CK: Conventional fertilization.

[0164] (2) T: Conventional fertilization + the multifunctional water-soluble fertilizer of this invention (according to the method in Example 1). Apply twice a year during the critical growth period of the crop, for two consecutive years.

[0165] 2. Measurement Indicators Soil chemical properties: pH, EC, organic matter content, and percentage of exchangeable sodium (ESP).

[0166] Crop yield: Annual production of corn and wheat.

[0167] 3. The test results are shown in Table 8 (mean ± standard deviation).

[0168] Table 8 Soil physicochemical properties and maize yield

[0169] 4. Conclusion Long-term application of the multifunctional water-soluble fertilizer of this invention can continuously reduce soil pH and EC value, increase organic matter content, reduce sodium ion damage, and significantly increase crop yield, indicating that it has long-term soil improvement and yield-increasing effects.

[0170] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A multifunctional water-soluble fertilizer, characterized by comprising: The raw materials include the following components by weight: potassium polysulfide 5-15 parts, potassium silicate 10-20 parts, sulfonated potassium humate 20-40 parts, and trace element chelate 5-10 parts. The trace element chelate is at least one of zinc, manganese, molybdenum, iron, and copper chelated with amino acid or EDTA.

2. The multifunctional water-soluble fertilizer according to claim 1, characterized in that, The multifunctional water-soluble fertilizer includes the following components by weight: potassium polysulfide 8-12 parts, potassium silicate 12-18 parts, sulfonated potassium humate 25-35 parts, and trace element chelate 6-8 parts.

3. The multifunctional water-soluble fertilizer according to claim 1 or 2, characterized by, The trace element chelate includes zinc amino acid, manganese amino acid, iron amino acid, and ammonium molybdate.

4. The multifunctional water-soluble fertilizer according to claim 1 or 2, characterized by, The degree of polymerization n of sulfur in the potassium polysulfide is 2-4.

5. The method for preparing the multifunctional water-soluble fertilizer according to any one of claims 1 to 4, characterized by, The method includes the following steps: Sulfonated potassium humate is dissolved in water to obtain a mother liquor; Potassium silicate and potassium polysulfide are sequentially dissolved in the mother liquor, and then mixed with trace element chelate to obtain the multifunctional water-soluble fertilizer.

6. The multifunctional water-soluble fertilizer of any one of claims 1-4 or prepared by the method of claim 5 is applied in at least one of the following: 1) promoting crop root development; 2) enhancing drought resistance of crops; 3) enhancing salt and alkali resistance of crops; 4) soil improvement; 5) improving fertilizer utilization rate; 6) increasing crop yield; and 7) improving crop quality.

7. The method for applying the multifunctional water-soluble fertilizer according to any one of claims 1 to 4 or the multifunctional water-soluble fertilizer prepared by the method according to claim 5, characterized in that, The method includes the following steps: The multifunctional water-soluble fertilizer is diluted 300-800 times with water to obtain a diluted solution, and the diluted solution is applied to the roots of crops.

8. The method of applying according to claim 7, wherein, The application time includes after crop transplanting and seedling recovery, during the critical growth period, or during stress.

9. The method of applying according to claim 8, wherein, The stress includes drought stress and / or salt and alkali stress.

10. The method of applying of claim 7, wherein, The application amount of the multifunctional water-soluble fertilizer is 3-10 kg per mu.

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