Phosphate fertilizer synergist based on horseradish tree leaf extract as well as preparation method and application of phosphate fertilizer synergist

Abstract

The invention discloses a moringa oleifera leaf extract-based phosphate fertilizer synergist as well as a preparation method and application thereof, and relates to the technical field of phosphate fertilizer synergists. The phosphate fertilizer synergist comprises the following components in parts by weight: 1-3 parts of moringa oleifera leaf extract, 1-3 parts of chitosan oligosaccharide fermentation liquor and 1-3 parts of yeast extract. Respectively weighing the yeast extract, the chitosan oligosaccharide fermentation liquor and the moringa oleifera leaf extract; mixing and continuously stirring at room temperature, adjusting the pH value to 6.0-6.5 by using diluted hydrochloric acid or a sodium hydroxide solution, and uniformly mixing to obtain the phosphate fertilizer synergist. The phosphate fertilizer synergist is applied in combination with monoammonium phosphate, or is used as a wrapping agent of monoammonium phosphate, or is mixed with monoammonium phosphate for granulation. The moringa oleifera leaf extract is wide in source, simple in processing mode and low in cost. The moringa oleifera leaf extract-chitosan oligosaccharide-yeast extract combination can significantly improve the phosphorus absorption process of plants, the leaf area is increased by 11.6%, the SPAD value is significantly improved, the nitrogen content of the overground part of the plants is improved by 31.7%, the phosphorus absorption is improved by 10.9%, and the soil alkaline phosphatase activity is improved by 53.7%.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphate fertilizer synergists, and in particular to a phosphate fertilizer synergist based on Moringa oleifera leaf extract, and a preparation method and application thereof. Background Art

[0002] Phosphate fertilizer is essential for maintaining and improving crop production, but phosphorus has poor mobility in the soil and its diffusion coefficient ranges from 10 -12 to 10 -15 m 2 / s, and easy to use with Al 3+ 、Fe 2+ and Ca 2+ Plasma forms phosphate precipitates, rapidly reducing the effectiveness of phosphate fertilizers applied to the soil. This significantly limits plant phosphorus absorption efficiency, resulting in a seasonal utilization rate of only 15-20% in the field. This low utilization rate not only results in a significant waste of phosphate rock resources, but also leads to the accumulation of large amounts of phosphorus in farmland soils, posing an environmental risk of eutrophication.

[0003] To promote the absorption of phosphorus fertilizers, biostimulants are usually added as synergists. Biostimulants are substances or microorganisms that can stimulate natural processes, promote plant nutrient absorption, improve nutrient efficiency, abiotic stress tolerance and crop quality traits, and have great potential in improving fertilizer utilization efficiency.

[0004] In recent years, research on biostimulants such as alginic acid, polyglutamic acid, and humic acid as efficiencies in phosphate fertilizers has gained increasing attention. For example, in a peanut-wheat rotation system, a combined application of diammonium phosphate and algae oligosaccharides increased wheat yield by 37.92% compared to applying phosphate fertilizer alone. Humic acid also has an effect on the apparent utilization rate of phosphate fertilizers. Some publicly available patented formulas involve combinations of biostimulants, such as algae oligosaccharides, γ-polyglutamic acid, chitosan oligosaccharides, and humic acid. These biostimulants are mixed in appropriate proportions and added to compound fertilizers (Patent Application No. 202110846773.1, A Compound Fertilizer and Its Preparation Method), phosphate fertilizers (Patent Application No. 201910589537.9, A Diammonium Phosphate Compound Fertilizer, Its Preparation Method and Application), or water-soluble fertilizers (Patent Application No. 202110938742.9, A Water-soluble Fertilizer Combining γ-polyglutamic acid and chitosan oligosaccharides). However, most of the biostimulant combinations currently used are products of microbial fermentation and are relatively expensive. Summary of the Invention

[0005] The purpose of the present invention is to provide a phosphate fertilizer synergist based on Moringa leaf extract, a preparation method and application thereof, so as to solve the problem of high cost of existing formulas.

[0006] To solve the above technical problems, the present invention adopts the following technical solution: a phosphate fertilizer synergist based on Moringa leaf extract, comprising the following components in parts by weight: 1-3 parts Moringa leaf extract 1-3 parts of chitosan oligosaccharide fermentation broth 1-3 parts yeast extract.

[0007] A further technical solution is that the yeast extract preparation method is as follows: the yeast strain is activated on a slant and then inoculated into a liquid culture medium, and cultured at 30°C for 24 hours; the bacteria are collected by centrifugation, suspended in deionized water, the pH is adjusted to 5-6, and autolyzed at 55°C for 6 hours; after inactivation, a complex enzyme is added for enzymatic hydrolysis for 4 hours, and the enzyme is inactivated in a boiling water bath; the supernatant is collected by centrifugation, concentrated under reduced pressure, and spray-dried to obtain a light yellow powdered yeast extract.

[0008] A further technical solution is that the chitosan oligosaccharide fermentation broth is prepared as follows: Aspergillus niger is used as the strain, inoculated into a liquid culture medium containing 2% chitosan, the initial pH is adjusted to 6.0, and fermented at 37°C for 72 hours. During the fermentation process, the dissolved oxygen content is controlled at 30%, and glucose is intermittently added to obtain the chitosan oligosaccharide fermentation broth.

[0009] A further technical solution is that the preparation method of the moringa leaf extract is as follows: after the moringa leaves are naturally air-dried, they are dried in a 60°C oven for 2 hours to constant mass, crushed with a wall-breaking machine, and sieved through a 50-mesh sieve to obtain moringa dry leaf powder; weigh the moringa dry leaf powder, add deionized water at a material-liquid ratio of 1:10m / V, treat in a 100°C boiling water bath for 1-2 hours, centrifuge to obtain the supernatant, extract the residue twice according to the above method, combine the supernatants, and dry to obtain the moringa leaf extract.

[0010] A further technical solution is that the preparation method of the phosphate fertilizer synergist is as follows: weigh yeast extract, chitosan oligosaccharide fermentation liquid, and Moringa leaf extract respectively; mix and continuously stir at room temperature, adjust the pH value to 60-6.5 with dilute hydrochloric acid or sodium hydroxide solution, and mix well to obtain the phosphate fertilizer synergist.

[0011] A further technical solution is that the molecular weight of the chitosan oligosaccharide is less than 2500Da.

[0012] A further technical solution is that the phosphate fertilizer synergist is used to enhance the synergy of monoammonium phosphate.

[0013] A further technical solution is to apply the phosphate fertilizer synergist in combination with monoammonium phosphate.

[0014] A further technical solution is that the phosphate fertilizer synergist is used as a coating agent for monoammonium phosphate or is mixed with monoammonium phosphate to form granules, and the added amount is 5-5.5 kg / ton monoammonium phosphate.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The phosphorus absorption of plants is completed jointly by the plant roots and their related microorganisms, and the three components in the formula play a role in plant root development, plant-microorganism interaction, and microorganism-microorganism interaction, thereby forming an overall synergistic effect and system regulation.

[0016] Moringa leaf extract primarily stimulates plant root growth and development. It contains over 92 active compounds, including vitamins, beta-carotene, amino acids, and ascorbic acid. Potassium, antioxidants, calcium, ascorbic acid, iron, and cytokinins are crucial factors influencing root development. Zeatin (a cytokinin) in particular can significantly regulate root morphology, promote lateral root development, and thus improve plant phosphorus absorption efficiency in the soil.

[0017] Chitosan oligosaccharides primarily enhance the symbiotic relationship between plants and AM fungi and beneficial soil bacteria. For example, arbuscular mycorrhizal fungi are a typical microorganism that promotes plant phosphorus absorption. Chitosan oligosaccharides are a key mycorrhizal factor involved in their symbiotic relationship with plants. Research by Volpe et al. has shown that exogenous addition of chitosan oligosaccharides can promote the upregulation of genes involved in strigolactone biosynthesis (CCD8-1 and CCD8-2) and transport (PDR1a) in alfalfa plants, thereby stimulating the differentiation of arbuscular mycorrhizal fungal hyphae, improving the colonization efficiency of arbuscular mycorrhizal fungi, and promoting plant phosphorus absorption.

[0018] Yeast extract primarily enhances phosphorus activation by improving the rhizosphere microenvironment and mobilizing beneficial microorganisms. Yeast extract contains a complete B-complex vitamin complex. Yeast extract is a mixture of amino acids, peptides, water-soluble vitamins, and carbohydrates. The various amino acids can mitigate microbial-microbial resource competition, improve the ecological relationships of rhizosphere microorganisms, strengthen cooperation among microorganisms, and thus stimulate the functions of soil microorganisms.

[0019] 2. Moringa leaf extract is widely available and easy to process, resulting in low cost. A combination of Moringa leaf extract, chitosan oligosaccharides, and yeast extract significantly improved plant phosphorus uptake, increasing leaf area by 11.6%, significantly improving SPAD values, raising aboveground nitrogen content by 31.7%, phosphorus uptake by 10.9%, and soil alkaline phosphatase activity by 53.7%. A Moringa leaf extract, yeast extract, and chitosan oligosaccharides formulation increased corn biomass by 27.47%, significantly surpassing the effect of applying the same mass of yeast extract (18.30%), chitosan oligosaccharides (11.82%), or Moringa leaf extract (6.18%) alone.

[0020] Through optimized formulations (Moringa leaf extract, yeast extract, and chitosan oligosaccharides are suitable for fertile soils with high organic matter content), the fertilizer is also suitable for calcareous soils. Compared to conventional monoammonium phosphate treatment, the addition of a phosphate fertilizer synergist increased plant aboveground biomass by 17.8-30.0%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Effects of various biostimulants on the dry weight (a) and phosphorus content (b) of corn aboveground parts.

[0022] Figure 2 Effects of biostimulant formulations on the dry weight (a) and phosphorus content (b) of corn aboveground parts.

[0023] Figure 3 To investigate the effects of combined application of phosphate fertilizer synergists and phosphate fertilizers on the growth characteristics of corn. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] Example 1 A phosphate fertilizer synergist based on Moringa leaf extract comprises the following components in parts by weight: 1-3 parts Moringa leaf extract 1-3 parts of chitosan oligosaccharide fermentation broth 1-3 parts yeast extract.

[0026] The yeast extract is prepared as follows: yeast strains are activated on a slant and inoculated into liquid culture medium, cultured at 30°C for 24 hours; the cells are harvested by centrifugation, suspended in deionized water, adjusted to a pH of 5-6, and autolyzed at 55°C for 6 hours; after inactivation, the cells are enzymatically hydrolyzed with a complex enzyme (neutral protease and β-glucanase) for 4 hours, and then inactivated in a boiling water bath; the supernatant is centrifuged, concentrated under reduced pressure, and spray-dried to obtain a light yellow powdered yeast extract. The purchased yeast strains were sourced from Hubei Angel Yeast Co., Ltd.

[0027] The chitosan oligosaccharide fermentation broth is prepared as follows: Aspergillus niger is inoculated into a liquid culture medium containing 2% chitosan. The initial pH is adjusted to 6.0, and the culture is fermented at 37°C for 72 hours. During the fermentation process, the dissolved oxygen level is controlled at 30%, and glucose is intermittently added to produce the chitosan oligosaccharide fermentation broth. The chitosan oligosaccharide is purchased from Shandong Weikang Biopharmaceutical Co., Ltd. Chitosan oligosaccharides have a molecular weight of less than 2500 Da. Although chitosan oligosaccharides with high molecular weights have poor solubility, those with low polymerization degrees have high solubility and are more easily absorbed by plants. However, low molecular weight chitosan oligosaccharides are more effective in enhancing the symbiotic relationship between plants and beneficial soil fungi (AM fungi).

[0028] The preparation method of Moringa leaf extract is as follows: after the Moringa leaves are naturally air-dried, they are dried in a 60°C oven for 2 hours to constant mass, crushed with a wall-breaking machine, and passed through a 50-mesh sieve to obtain Moringa dry leaf powder; the Moringa dry leaf powder is weighed, deionized water is added at a material-liquid ratio of 1:10 m / V, the mixture is treated in a 100°C boiling water bath for 1-2 hours, the supernatant is obtained by centrifugation, the residue is extracted twice according to the above method, the supernatants are combined, and the Moringa leaf extract is obtained after drying.

[0029] Weigh 1 part of yeast extract, 1 part of chitosan oligosaccharide fermentation liquid, and 1 part of Moringa oleifera leaf extract respectively; mix them at room temperature with continuous stirring, adjust the pH value to 6.5 with dilute hydrochloric acid or sodium hydroxide solution, and mix them thoroughly to obtain a phosphate fertilizer synergist.

[0030] The method of using the above-mentioned phosphate fertilizer synergist is as follows: 1. Use directly with phosphate fertilizer, specifically, After adding water-soluble monoammonium phosphate to the soil, the phosphate fertilizer synergist composition is added and applied by flushing or drip irrigation. The application rate is 60 mg / kg soil based on the raw material.

[0031] The drip irrigation and flushing method comprises dripping a solution of the phosphate fertilizer synergist composition with water, and applying the phosphate fertilizer synergist composition to the soil once. Alternatively, the phosphate fertilizer synergist composition is mixed with fine sand and applied to the soil together with fertilizer, followed by timely irrigation, and applying the bioactivator once.

[0032] 2. As a coating agent for ammonium phosphate fertilizer or mixed with it for granulation, specifically

[0033] Coating granulation: A coating machine is used to coat the surface of monoammonium phosphate after the phosphate fertilizer synergist is evenly mixed. The addition rate is 5 kg per ton of fertilizer (10-45-0). A heating device is used during the process to maintain the temperature at around 50°C. The granules are then sieved through a 2 mm sieve and dried. The content of the phosphate fertilizer synergist composition can be adjusted flexibly, ranging from 0.015% to 0.5%.

[0034] Uniform mixing and granulation: Use a solid coating machine, mix the phosphate fertilizer synergist and monoammonium phosphate in powder form, add 5 kg per ton of fertilizer (10-45-0), extrude granules, pass through a 2 mm sieve, and dry.

[0035] Extrusion Granulation: Pulverize the phosphate fertilizer synergist and the phosphate fertilizer raw materials using a high-speed grinder, pass through a 0.5 mm mesh, and set aside. Weigh the appropriate amount of raw material powder and mix it with a small amount of monoammonium phosphate. After mixing, gradually add more monoammonium phosphate and grind it in a high-speed grinder for 30 seconds to 1 minute until completely mixed. This will produce monoammonium phosphate containing 1% phosphate fertilizer synergist. Weigh 25 g, 7.5 g, and 0.75 g of the prepared monoammonium phosphate, respectively, and add monoammonium phosphate to bring the total mass to 50 g. After mixing, monoammonium phosphate with phosphate fertilizer synergist content of 0.5%, 0.15%, and 0.015% is obtained. For tableting and granulation using a mold: Take a small amount of the mixed raw materials, spray the surface with water 2-3 times, and stir until agglomerated granules are formed. Use a spatula to scoop out the granules and place them in a mold. Compact them with a rubber hammer, remove them, and dry them at 60°C for 10-15 minutes.

[0036] In order to verify the effects of each component and their synergistic effects, the following tests were conducted: 1. Comparison of the effects of Moringa leaf extract on plant phosphorus absorption (1) Test materials The corn variety used in the test was Zhengdan 958. The test soil was collected from the experimental field at the Quzhou Experimental Station of China Agricultural University. The basic soil nutrients were: 69.8 mg / kg alkaline-hydrolyzable nitrogen, 14.7 mg / kg available phosphorus, and 229.5 mg / kg available potassium. The collected soil was cleaned of debris and residual roots, air-dried, and passed through a 2 mm sieve.

[0037] The 20 biostimulants tested are shown in Table 1.

[0038] (2) Experimental design The experiment used a randomized block design with a control (CK) and 17 biostimulant treatments, with four replicates per treatment. The biostimulant concentration was set at 50 mg / kg. Deionized water was used to prepare the corresponding solutions, and water-insoluble agents were mixed with the potting soil before sowing. During corn thinning, 200 mL of biostimulant solution was added to each pot, while the same amount of deionized water was added to the control. The pot experiment was conducted from June to August 2023 in the intelligent greenhouse at the Quzhou Experimental Station of China Agricultural University. Each pot contained 2 kg of potting soil, and three surface-sterilized and germinated corn seeds were sown. After seven days of growth, the seedlings were thinned out, leaving only one uniformly growing seedling.

[0039] After six weeks of growth, corn plant height, stem diameter, leaf area, and SPAD were measured. Aboveground parts were cut, sterilized at 105°C, and then oven-dried at 60°C for dry weight. Nitrogen and phosphorus content in aboveground parts were determined by grinding the dried corn plants and digesting them using a combined H₂SO₄-H₂O₂ digestion method. Total nitrogen and total phosphorus content were then determined using a Kjeldahl nitrogen analyzer and a vanadium-molybdenum yellow colorimetric method, respectively.

[0040] (3) Test results Compared to the control, Moringa leaf extract alone increased aboveground biomass by 6.18%, a slightly lower effect than other biostimulants such as yeast extract and chitosan oligosaccharides. However, Moringa leaf extract showed a similar effect on aboveground phosphorus content as the 14 other biostimulants, with all showing a significant effect, with Moringa leaf extract achieving a moderate increase of 16%. However, compared to the other substances, Moringa leaf extract was the least expensive.

[0041] 2. Comparison of the effects of the synergist composition formed by Moringa leaf extract (1) Test materials The corn variety used in the test was Zhengdan 958. The test soil was collected from the experimental field at the Quzhou Experimental Station of China Agricultural University. The basic soil nutrients were: 69.8 mg / kg alkaline-hydrolyzable nitrogen, 14.7 mg / kg available phosphorus, and 229.5 mg / kg available potassium. The collected soil was cleaned of debris and residual roots, air-dried, and passed through a 2 mm sieve.

[0042] (2) Experimental design All biostimulants with significant effects were divided into three types and then combined. A total of 17 biostimulant compositions were obtained (Table 2). These compositions were applied at a concentration of 60 mg / kg. The rest of the design was the same as in Example 1. (3) Test results Only three biostimulant combinations were effective in promoting corn plant height. The chitosan oligosaccharide-polyglutamic acid-glucose treatment achieved a plant height of 58.7 cm, an 18.3% increase compared to the CK treatment. Furthermore, two synergistic combinations based on Moringa leaf extract (Moringa leaf extract-chitosan oligosaccharide-yeast extract; Moringa leaf extract-yeast extract-arginine) increased leaf area by 11.6% and 5.2%, respectively.

[0043] Moringa leaf extract, chitosan oligosaccharide, and yeast extract increased the aboveground dry weight of corn by 27.6%, boosted aboveground nitrogen content by 31.7%, increased phosphorus uptake by 10.9%, and increased soil alkaline phosphatase activity by 53.7%. Overall, Moringa leaf extract, chitosan oligosaccharide, and yeast extract were among the most effective phosphate fertilizer combinations, and their cost was significantly lower than the most effective comparison (chitosan oligosaccharide, polyglutamic acid, and glucose).

[0044] 3. Evaluation of the effect of combining phosphate fertilizer synergists with phosphate fertilizer granulation Test materials: Soil and plant seeds are the same as in Example 1 Granulation of phosphate fertilizer synergist and monoammonium phosphate: Both the biostimulant and phosphate fertilizer raw materials were ground using a high-speed grinder, passed through a 0.5 mm mesh, and set aside. Weigh the appropriate amount of raw material powder and mix it with a small amount of monoammonium phosphate. After mixing, gradually add more monoammonium phosphate and grind it in a high-speed grinder for 30 seconds to 1 minute until completely mixed. This yields monoammonium phosphate containing 1% phosphate fertilizer synergist. Weigh 25 g, 7.5 g, and 0.75 g of the monoammonium phosphate containing phosphate fertilizer synergist, respectively, and add monoammonium phosphate to bring the total mass to 50 g. After mixing, these monoammonium phosphate synergists are obtained with 0.5%, 0.15%, and 0.015% phosphate synergist content. For tableting and granulation, use a mold: Take a small amount of the mixed raw materials, spray the surface with water 2-3 times, and stir until agglomerated granules are formed. Use a spatula to scoop out the granules and place them in a mold. Compact them with a rubber hammer, remove them, and dry them at 60°C for 10-15 minutes.

[0045] Experimental design The potted plant experiment was conducted in the smart greenhouse of the Quzhou Experimental Station of China Agricultural University from June to August 2024. This experiment used a randomized block design with the following control groups: (1) blank control (CK): no phosphate fertilizer was added to the potted plants; (2) monoammonium phosphate control (MAP): ordinary MAP was used; and (3) a phosphate fertilizer synergist formula (Moringa leaf extract-chitooligosaccharide-yeast extract) was set at four fertilizer addition rates of 0.015%, 0.15%, 0.5%, and 1% (w / w). Each treatment had four replicates. Phosphate fertilizer was applied by broadcasting, with phosphate fertilizer granules evenly spread 2-4 cm around the seeds and 10 cm below the soil surface to simulate hole / row application in large fields.

[0046] Test results The aboveground dry weight data were analyzed, and the results showed that compared with the ordinary monoammonium phosphate treatment, the aboveground biomass of plants increased by 30.0%, 14.3%, 28.9% and 17.8% after adding phosphate fertilizer synergists.

[0047] 4. Field evaluation of the application of phosphate fertilizer synergists and phosphate fertilizer granulation Test materials: In field trials, the enhanced fertilizer, when applied in combination with conventional fertilizers, demonstrated improved plant physiological parameters and nutrient utilization efficiency, demonstrating its agronomic benefits. The enhanced fertilizer mixture powder was added to monoammonium phosphate (MAP) raw material at concentrations of 0.15% and 0.015%, and granulated to produce fertilizer granules with diameters ranging from 2 to 4 mm. Each treatment was applied as a topdressing fertilizer at the jointing stage of corn at a rate of 10.5 kg P2O5 hm2. -2 Apply nitrogen in rows, and the difference in nitrogen between treatments will be deducted from the topdressing urea. Apply nitrogen evenly in furrows along the midline of two rows of corn at 10 cm from the soil surface.

[0048] Experimental Design: The experiment included six treatments with four replicates. (1) Blank control: no topdressing of phosphate fertilizer; (2) Monoammonium phosphate control: monoammonium phosphate; (3) Positive control: polyglutamic acid / humic acid enhanced monoammonium phosphate; (4) Treatment 1: 0.015% formula enhanced monoammonium phosphate; (5) Treatment 2: 0.15% formula enhanced monoammonium phosphate.

[0049] Sample sampling and measurement method: 1. Determine the planting area of the plot and count the number of corn plants and ears within the plot. Due to the small size of the plot, all corn within the plot must be broken off for yield measurement. 2. Seed Testing: Measure the cob width, cob length, number of kernels per row, and number of rows. After threshing the corn, measure the kernel fresh weight, moisture content, and thousand-kernel weight. Sampling Process: Count the number of corn plants and ears in each split plot and keep a record. Break off all corn within the split plot, bag it individually, and take it home.

[0050] Test results: In the field, topdressing with phosphate fertilizer increased yield by 9.79%, 10.46%, and 11.33%, respectively, compared to the control, and the partial productivity of phosphate fertilizer increased by 2.29-3.72%. Adding 0.015% of the formula increased corn ear width by 4.08%, and adding 0.15% of the formula increased corn kernel number by 7.83%. Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope of this disclosure.

Claims

1. A phosphate fertilizer synergist based on Moringa leaf extract, characterized in that: The composition comprises the following components in parts by weight: 1-3 parts Moringa leaf extract 1-3 parts of chitosan oligosaccharide fermentation broth 1-3 parts yeast extract.

2. A phosphate fertilizer synergist based on Moringa leaf extract according to claim 1, characterized in that: The yeast extract preparation method is as follows: yeast strains are activated on a slant surface and then inoculated into a liquid culture medium, and cultured at 30°C for 24 hours; the yeast cells are collected by centrifugation, suspended in deionized water, adjusted to a pH of 5-6, and autolyzed at 55°C for 6 hours; after inactivation, a complex enzyme is added for enzymatic hydrolysis for 4 hours, and the enzyme is inactivated in a boiling water bath; the supernatant is collected by centrifugation, concentrated under reduced pressure, and spray-dried to obtain a light yellow powdered yeast extract.

3. A phosphate fertilizer synergist based on Moringa leaf extract according to claim 1, characterized in that: The chitosan oligosaccharide fermentation liquid is prepared as follows: Aspergillus niger is used as the strain, inoculated into a liquid culture medium containing 2% chitosan, the initial pH is adjusted to 6.0, and fermented at 37°C for 72 hours. During the fermentation process, the dissolved oxygen content is controlled at 30% and glucose is intermittently added to obtain the chitosan oligosaccharide fermentation liquid.

4. A phosphate fertilizer synergist based on Moringa leaf extract according to claim 1, characterized in that: The preparation method of the moringa leaf extract is as follows: after the moringa leaves are naturally air-dried, they are dried in a 60°C oven for 2 hours to constant mass, crushed with a wall-breaking machine, and sieved through a 50-mesh sieve to obtain moringa dry leaf powder; the moringa dry leaf powder is weighed, deionized water is added according to a material-liquid ratio of 1:10 m / V, the powder is treated in a 100°C boiling water bath for 1-2 hours, the supernatant is obtained by centrifugation, the residue is extracted twice according to the above method, the supernatants are combined, and the powder is dried to obtain the moringa leaf extract.

5. A phosphate fertilizer synergist based on Moringa leaf extract according to any one of claims 1 to 4, characterized in that: The preparation method of the phosphate fertilizer synergist is as follows: respectively weighing yeast extract, chitosan oligosaccharide fermentation liquid, and Moringa oleifera leaf extract; mixing and continuously stirring at room temperature, adjusting the pH value to 6.0-6.5 with dilute hydrochloric acid or sodium hydroxide solution, and mixing to obtain the phosphate fertilizer synergist.

6. A phosphate fertilizer synergist based on Moringa leaf extract according to claim 5, characterized in that: The molecular weight of the chitosan oligosaccharide is less than 2500Da.

7. A phosphate fertilizer synergist based on Moringa leaf extract according to claim 5, characterized in that: The phosphate fertilizer synergist is used for enhancing the effectiveness of monoammonium phosphate.

8. A phosphate fertilizer synergist based on Moringa leaf extract according to claim 7, characterized in that: The phosphate fertilizer synergist is applied in combination with monoammonium phosphate.

9. A phosphate fertilizer synergist based on Moringa leaf extract according to claim 7, characterized in that: The phosphate fertilizer synergist is used as a coating agent for monoammonium phosphate or is mixed with monoammonium phosphate to form granules, and the added amount is 0.15-5 kg / ton of monoammonium phosphate.

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