Polyglutamic acid chelated calcium fertilizer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of agricultural fertilizers, and particularly discloses a polyglutamic acid chelated calcium fertilizer as well as a preparation method and application thereof. The polyglutamic acid chelated calcium fertilizer provided by the invention is prepared from the following components: polyglutamic acid fermentation liquor, a calcium source and seaweed essence, the dosage of the calcium source is 70-80% of the total volume of the polyglutamic acid fermentation liquor; the content of polyglutamic acid in the polyglutamic acid fermentation liquor is 30-45 g / L, and the molecular weight of the polyglutamic acid is 180-2 million Da; the preparation method of the polyglutamic acid fermentation liquor comprises the following steps: carrying out fermentation culture on bacillus subtilis in a fermentation culture medium to obtain the polyglutamic acid fermentation liquor, the formula of the fermentation culture medium comprises 5-10 g / L of glutamic acid, 5-10 g / L of glucose and 60-70 g / L of yeast extract powder. The polyglutamic acid chelated calcium fertilizer provided by the invention has the advantages that the polyglutamic acid chelated calcium fertilizer can be easily absorbed by crop roots, the absorption rate of calcium ions in plants is high, and the yield of crops can be greatly increased when the polyglutamic acid chelated calcium fertilizer is applied to the crops.

Description

Technical Field

[0001] The present application relates to the technical field of agricultural fertilizers, and in particular to a polyglutamic acid chelated calcium fertilizer and a preparation method and application thereof. Background Art

[0002] Calcium is one of the important elements in the growth process of plants. On the one hand, it can combine with pectin in the cell wall to form a stable network structure, thereby increasing the firmness and stability of the cell wall; on the other hand, it can also act as a signal molecule in the plant body to transmit information between cells, thereby helping plants adapt to environmental changes and make physiological adjustments; in addition, calcium ions can promote the absorption of nutrients such as nitrogen and phosphorus by plant roots, and transport them to various parts of the plant body through the xylem and phloem to meet the growth and development needs of the plant. Therefore, calcium plays a variety of important roles in plant growth, and these roles together provide guarantees for the normal growth and development of plants.

[0003] Studies have shown that calcium ions in calcium fertilizers are mainly absorbed through the root system, and then transported intracellularly and intercellularly to various parts of the plant body; however, the calcium fertilizers currently used are mainly the following: one is inorganic salt calcium fertilizers, which are easily fixed in the soil, making it difficult for the roots to absorb; the second is chelated calcium fertilizers such as EDTA, DTPA, EDDHA, HEDTA, IDS, etc., which are relatively stable in the soil, but have a large molecular weight and are difficult for plants to absorb and reuse; the third is amino acid, humic acid and citric acid chelated calcium fertilizers. The chelating agents in this type of calcium fertilizers can be absorbed and utilized by crops on the one hand, and can also carry calcium ions to the phloem on the other hand, providing sufficient nutrition for plant growth and development. However, since the chelating ability of this type of chelating agent is not very strong, the actual chelated amount of calcium ions is insufficient, resulting in unstable calcium fertilizers and general use effects. Summary of the invention

[0004] In order to overcome the problems of difficulty in root absorption and calcium ion transportation in plants in existing calcium fertilizers, the present application provides a polyglutamic acid chelated calcium fertilizer and a preparation method and application thereof.

[0005] The polyglutamic acid chelated calcium fertilizer provided in this application adopts the following technical scheme: A polyglutamic acid chelated calcium fertilizer comprises the following components: polyglutamic acid fermentation liquid, a calcium source and seaweed extract; the amount of the calcium source is 70-80% of the total volume of the polyglutamic acid fermentation liquid; The content of polyglutamic acid in the polyglutamic acid fermentation broth is 30-45 g / L, and the molecular weight of polyglutamic acid is 1.8-2 million Da.

[0006] In the present application, polyglutamic acid is a plant growth regulator with good water solubility, strong chelating adsorption capacity, and easy to be absorbed and transported by crops. Polyglutamic acid is mixed with a calcium source to prepare fertilizer. On the one hand, polyglutamic acid can enhance the stress resistance of crops and promote the growth and development of crops; on the other hand, polyglutamic acid can chelate with calcium ions to form a stable chelate. While polyglutamic acid is absorbed and utilized by crops, calcium ions are also carried and transported to the xylem and phloem of plants, thereby improving the absorption and utilization rate of calcium ions by crops and promoting the growth and development of crops; in addition, polyglutamic acid is a biostimulant that can stimulate the regeneration of root hairs and the growth of root systems, improve the ability of crop roots to absorb nutrients, and then improve crop yield and quality. The addition of seaweed essence can control the transformation of crops from vegetative growth to reproductive growth, improve the absorption and utilization rate of crop calcium, avoid crop leggy growth without fruiting, and avoid greedy green late maturity and early aging of crops during the fruiting period. Therefore, the polyglutamate chelated calcium fertilizer prepared by the polyglutamate fermentation liquid, calcium source and seaweed essence in the present application has the advantages of easy absorption by crop roots and high absorption rate of calcium ions in plants. The use of the above-mentioned polyglutamate chelated calcium fertilizer for crop fertilization can, on the one hand, enhance the tolerance of plants to various adversities, including saline-alkali stress, low temperature, drought, etc.; on the other hand, it can improve the effectiveness of trace elements such as iron, zinc, and calcium in the soil and the absorption capacity of plants, thereby improving the quality and yield of crops.

[0007] In the present application, polyglutamic acid is a polymer compound formed by connecting multiple glutamic acid molecules through peptide bonds. The large number of carboxyl groups on its side chain gives it a strong chelating ability; as the molecular weight increases, the number of carboxyl groups in the polyglutamic acid molecule also increases accordingly, thereby providing more chelating sites; these sites can strongly interact with calcium ions to form a chelate with high calcium ion chelation capacity and stable structure.

[0008] Optionally, the calcium source is used in an amount of 73-78% of the total volume of the polyglutamic acid fermentation broth.

[0009] In some embodiments, the calcium source may be present in an amount of 70-73%, 70-75%, 70-78%, 70-80%, 73-75%, 73-78%, 73-80%, 75-78%, 75-80% or 78-80% of the total volume of the polyglutamic acid fermentation broth.

[0010] In a specific embodiment, the amount of the calcium source can be 70%, 73%, 75%, 78% or 80% of the total volume of the polyglutamic acid fermentation broth.

[0011] Optionally, the method for preparing the polyglutamic acid fermentation broth comprises the following steps: fermenting Bacillus subtilis in a fermentation medium to obtain the polyglutamic acid fermentation broth; the fermentation medium formula is: 5-10 g / L glutamic acid, 5-10 g / L glucose, and 60-70 g / L yeast extract powder.

[0012] Optionally, the calcium ion content in the calcium source is 160-190 g / L.

[0013] Optionally, the preparation method of the calcium source comprises the following steps: adding nitric acid to shell powder or bone powder and hydrolyzing it for 48 hours; then adding composite bacteria thereto and hydrolyzing it at 30-40°C for 7-10 days, then concentrating and filtering with an evaporator, taking the supernatant and obtaining the calcium source.

[0014] Optionally, the viable bacteria count of the composite bacteria is ≥100 billion / g, and the composite bacteria is a mixture of Bacillus subtilis, Bacillus licheniformis, lactic acid bacteria and Rhodopseudomonas palustris with a viable bacteria count ratio of 2:2:3:3.

[0015] Optionally, based on the volume of the polyglutamic acid fermentation broth, the amount of the seaweed extract is 15-30 g / L.

[0016] Optionally, based on the volume of the polyglutamic acid fermentation broth, the amount of the seaweed extract is 20-25 g / L.

[0017] In this application, the amount of seaweed essence added will affect the effect of polyglutamic acid chelated calcium fertilizer. Through experimental research, this application found that by further controlling the amount of seaweed essence added to 2-2.5% of the total weight of polyglutamic acid fermentation liquid, the obtained polyglutamic acid chelated calcium fertilizer was applied to tomato plants, and the fruit setting rate of tomatoes could reach more than 80%, and the yield could reach more than 28,000 kg / mu.

[0018] In some embodiments, the amount of seaweed essence can be 15-20 g / L, 15-25 g / L, 15-30 g / L, 20-25 g / L, 20-30 g / L or 25-30 g / L.

[0019] In a specific embodiment, the amount of seaweed essence can also be 15g / L, 20g / L, 25g / L or 30g / L.

[0020] In a second aspect, the present application provides a method for preparing polyglutamate chelated calcium fertilizer.

[0021] A preparation method of polyglutamic acid chelated calcium fertilizer comprises the following steps: gradually adding a calcium source to polyglutamic acid fermentation liquid under stirring, controlling the stirring speed to be 300-500 r / min for 60-120 min to obtain a polyglutamic acid chelated calcium solution; and then adding seaweed extract to the polyglutamic acid chelated calcium solution, stirring evenly to obtain the polyglutamic acid chelated calcium fertilizer.

[0022] In the present application, the speed and time of mixing the polyglutamic acid fermentation liquid and the calcium source will affect the chelation efficiency of polyglutamic acid to calcium ions, thereby affecting the use effect of polyglutamic acid chelated calcium fertilizer. The present application found through experimental research that by controlling the stirring speed and time within the above range, the use effect of the obtained polyglutamic acid chelated calcium fertilizer is better, which can increase the yield of tomatoes.

[0023] In some embodiments, the stirring speed may be 300-350 r / min, 300-400 r / min, 300-450 r / min, 300-500 r / min, 350-400 r / min, 350-450 r / min, 350-500 r / min, 400-450 r / min, 400-500 r / min or 450-500 r / min.

[0024] In a specific embodiment, the stirring speed can also be 300 r / min, 350 r / min, 400 r / min, 450 r / min or 400-500 r / min.

[0025] In some embodiments, the stirring time may be 60-90 min or 90-120 min.

[0026] In a specific embodiment, the stirring time can also be 60 min, 90 min or 120 min.

[0027] In a second aspect, the present application provides an application of polyglutamate chelated calcium fertilizer in the cultivation of fruits and vegetables.

[0028] Optionally, the application amount of the polyglutamate chelated calcium fertilizer is 8-12 kg / mu.

[0029] In summary, this application has the following beneficial effects: 1. The present application adopts polyglutamic acid fermentation liquid, calcium source and seaweed essence to prepare a polyglutamic acid chelated calcium fertilizer, which has good water solubility and high calcium ion chelating capacity. The above polyglutamic acid chelated calcium fertilizer is used as fruits and vegetables, which can greatly improve the yield and quality of fruits and vegetables.

[0030] 2. The present application further controls the amount of calcium source added to the polyglutamate chelated calcium fertilizer within the range of 73-78% of the total volume of the polyglutamate fermentation broth, and the amount of seaweed extract added to the polyglutamate chelated calcium fertilizer is controlled within the range of 2-2.5% of the total weight of the polyglutamate fermentation broth. The obtained polyglutamate chelated calcium fertilizer can increase the yield and quality of tomatoes, the tomato fruit setting rate can reach more than 80%, the yield can reach more than 28,000 kg / mu, and the VC content can reach more than 298.0 mg / kg. DETAILED DESCRIPTION

[0031] The present application provides a polyglutamic acid chelated calcium fertilizer, comprising the following components: polyglutamic acid fermentation liquid, a calcium source and seaweed essence; the amount of the calcium source is 70-80% of the total volume of the polyglutamic acid fermentation liquid, and the calcium ion content in the calcium source is 160-190 g / L; the content of polyglutamic acid in the polyglutamic acid fermentation liquid is 30-45 g / L, and the molecular weight of polyglutamic acid is 1.8-2 million Da; further, based on the volume of the polyglutamic acid fermentation liquid, the amount of the seaweed essence is 15-30 g / L; further, the amount of the calcium source is 73-78% of the total volume of the polyglutamic acid fermentation liquid, and the amount of the seaweed essence is 20-25 g / L.

[0032] The preparation method of polyglutamic acid fermentation liquid comprises the following steps: inoculating activated Bacillus subtilis into a 300mL triangular flask containing 50mL fermentation medium, culturing for 10 hours under shaking conditions of 37°C and 200r / min to obtain Bacillus subtilis seed liquid; inoculating the above seed liquid into a 7.5L fermentation tank pre-loaded with 4.5L sterilized fermentation medium at a seed amount of 5% (v / v) for culturing under the conditions of 37°C, 600r / min, and 10 hours, and fermenting to obtain polyglutamic acid fermentation liquid. The fermentation medium formula is: 5-10g / L glutamic acid, 5-10g / L glucose, and 60-70g / L yeast extract powder.

[0033] The preparation method of the calcium source comprises the following steps: adding 60% nitric acid to shell powder, hydrolyzing for 40-50 hours; then adding composite bacteria thereto, hydrolyzing at 30-40°C for 7-10 days, then concentrating and filtering by an evaporator, taking the supernatant, and obtaining the calcium source. The amount of 60% nitric acid added is 3-5 times that of shell powder; the amount of composite bacteria added is 0.1-0.3wt% of shell powder; the number of viable bacteria of the composite bacteria is ≥100 billion / g, and the composite bacteria is a mixture of Bacillus subtilis, Bacillus licheniformis, lactic acid bacteria and Rhodopseudomonas palustris with a ratio of 2:2:3:3.

[0034] The preparation method of polyglutamate chelated calcium fertilizer provided by the present application comprises the following steps: gradually adding a calcium source to a polyglutamate fermentation liquid under stirring, controlling the stirring speed to 300-500 r / min for 60-120 min to obtain a polyglutamate chelated calcium solution; and then adding seaweed extract to the polyglutamate chelated calcium solution, stirring evenly, to obtain a polyglutamate chelated calcium fertilizer.

[0035] In the present application, glutamic acid was purchased from Shandong Qianfeng Agricultural Technology Co., Ltd.; glucose was purchased from Inner Mongolia Fufeng Biotechnology Co., Ltd.; yeast extract powder was purchased from Angel Angel Yeast Co., Ltd.; seaweed extract was purchased from Shandong Crystal Group Co., Ltd.; Bacillus subtilis, Bacillus licheniformis, lactic acid bacteria and Rhodopseudomonas palustris were all bacterial powders purchased from Shandong Weilan Biotechnology Co., Ltd.; the raw materials, reagents, solvents, etc. of the present application can all be obtained commercially.

[0036] The present application is further described in detail below in combination with preparation examples, embodiments and performance testing experiments.

[0037] Examples 1-5 Embodiments 1-5 respectively provide a polyglutamic acid chelated calcium fertilizer.

[0038] The difference between the above embodiments is that the amount of calcium source added to the polyglutamic acid fermentation broth is specifically shown in Table 1 below.

[0039] The preparation method of polyglutamic acid chelated calcium fertilizer provided in Examples 1-5 comprises the following steps: (1) Preparation of polyglutamic acid fermentation liquid: The activated Bacillus subtilis was inoculated into a 300mL Erlenmeyer flask containing 50mL of fermentation medium, and cultured for 10 hours at 37°C and 200r / min of shaking table to obtain Bacillus subtilis seed liquid; the seed liquid was inoculated into a 7.5L fermentation tank pre-filled with 4.5L of sterilized fermentation medium at a seed amount of 5% (v / v) for culture under the conditions of 37°C and 600r / min for 10 hours. After fermentation, a polyglutamic acid fermentation liquid with a polyglutamic acid content of 40g / L and a molecular weight of 2 million Da was obtained. The fermentation medium formula is: 8g / L of glutamic acid, 8g / L of glucose, and 65g / L of yeast extract powder.

[0040] (2) Preparation of calcium source: Add 2kg of 60% nitric acid to 500g of shell powder and hydrolyze for 48h; then add 1g of composite bacteria and hydrolyze at 37°C for 8 days, then use an evaporator to concentrate and filter, take the supernatant, and obtain a calcium source with a calcium ion content of 180g / L. The number of viable bacteria of the composite bacteria is 100 billion / g, and the composite bacteria is a mixture of Bacillus subtilis, Bacillus licheniformis, lactic acid bacteria and Rhodopseudomonas palustris with a ratio of 2:2:3:3.

[0041] (3) Under stirring, gradually add calcium source (the amount added is shown in Table 1) to 1L of polyglutamic acid fermentation broth, control the stirring speed to 400r / min, and the time to 90min to obtain polyglutamic acid chelated calcium solution; then add 20g of seaweed extract to the above solution, stir evenly, and obtain polyglutamic acid chelated calcium fertilizer.

[0042] Table 1 The amount of calcium source added in the polyglutamic acid chelated calcium fertilizer provided in Examples 1-5 Embodiment 6-9 Examples 6-9 each provide a polyglutamic acid chelated calcium fertilizer.

[0043] The difference between the above embodiment and embodiment 3 is that the amount of seaweed extract added to the polyglutamic acid fermentation broth is specifically shown in Table 2 below.

[0044] Table 2 Addition amount of seaweed extract in polyglutamic acid chelated calcium fertilizer provided in Example 3, Example 6-9 Examples 10-15 Examples 10-15 each provide a polyglutamic acid chelated calcium fertilizer.

[0045] The difference between the above embodiment and embodiment 3 is that the stirring speed and time in step (3) are specifically shown in Table 3 below.

[0046] Table 3 Stirring speed and time in step (3) of Example 3 and Examples 10-15 Comparative Example 1 Comparative Example 1 provides a polyglutamic acid chelated calcium fertilizer.

[0047] The difference between the comparative example and Example 3 is that the amount of calcium source added to the polyglutamic acid fermentation broth is 650 mL.

[0048] Comparative Example 2 Comparative Example 2 provides a polyglutamic acid chelated calcium fertilizer.

[0049] The difference between the comparative example and Example 3 is that the amount of calcium source added to the polyglutamic acid fermentation broth is 950 mL.

[0050] Comparative Example 3 Comparative Example 3 provides a polyglutamic acid chelated calcium fertilizer.

[0051] The difference between the comparative example and Example 3 is that the amount of seaweed extract added to the polyglutamic acid fermentation broth is 0.

[0052] Comparative Example 4 Comparative Example 4 provides a polyglutamic acid chelated calcium fertilizer.

[0053] The difference between the comparative example and Example 3 is that the stirring speed in step (3) is 200 r / min.

[0054] Comparative Example 5 Comparative Example 5 provides a polyglutamic acid chelated calcium fertilizer.

[0055] The difference between the comparative example and Example 3 is that the stirring speed in step (3) is 600 r / min.

[0056] Performance testing The performance of the polyglutamic acid chelated calcium fertilizers obtained in Examples 1-15 and Comparative Examples 1-5 was investigated, and the results are shown in Table 4 below.

[0057] 1. Experimental location: No. 10 solar greenhouse, Institute of Vegetable and Floriculture, Chinese Academy of Agricultural Sciences.

[0058] 2. Experimental method: Cherry tomatoes (Fengzhu 409) were sown in plug trays on January 1, 2022, and planted in fertilized soil on January 30, with a planting spacing of 35 cm and double rows; in the early growth stage of cherry tomatoes, a large area of ​​tomatoes in the greenhouse appeared dwarfed plants, with curled leaves and yellowing leaf margins, especially the top leaves faded green and yellowed and became smaller. 21 test plots were drawn in the greenhouse (each test plot was 5.4m×1.4m, and the interval between each two test plots was at least 1m), of which 15 test plots were applied with polyglutamic acid chelated calcium fertilizer provided in Examples 1-15, named as test groups 1-15; 5 test plots were applied with polyglutamic acid chelated calcium fertilizer provided in Comparative Examples 1-5, named as control groups 1-5; 1 test plot was not fertilized and served as a blank group.

[0059] The fertilization method of the above-mentioned polyglutamic acid chelated calcium fertilizer is: according to the usage amount of 10kg / mu, dilute the polyglutamic acid chelated calcium fertilizer 500 times, and apply it to the root system of the tomato plant, the number of applications is 2 times, and the interval time is 10 days.

[0060] 3. Test results: (1) In the middle growth period of tomatoes, the flowering and fruit setting of tomato plants were counted, and the fruit setting rate was calculated. The calculation formula of the fruit setting rate is as follows: Fruit setting rate = number of fruits / number of flowers × 100% (2) From the end of May to the end of June, cherry tomatoes began to mature gradually. Tomatoes in each experimental area were harvested gradually, once a week until all the tomatoes were harvested. The tomato yield of each experimental area was counted (in terms of per mu), and the iodine titration method was used to detect the VC content in the tomatoes.

[0061] Table 4 Performance test results of polyglutamic acid chelated calcium fertilizer in tomato plants The test results of Examples 1-5 and Comparative Examples 1-2 show that with the increase in the amount of calcium source added, the fruit setting rate of tomato plants shows a trend of first increasing and then remaining basically unchanged, and the yield and quality show a trend of first increasing and then decreasing; after fertilizing the tomato plants with the polyglutamate chelated calcium fertilizer obtained in Examples 1-5, the fruit setting rate of tomatoes is 74.3-86.7%, the yield is 27281-28546 kg / mu, and the VC content in tomatoes is 294.3-300.3 mg / kg; and after fertilizing the tomato plants with the polyglutamate chelated calcium fertilizer obtained in Comparative Examples 1-2, the fruit setting rate of tomatoes is 65.28-68.43%, the yield is 25873-26456 kg / mu, and the VC content in tomatoes is 288.5-291.3 mg / kg. Therefore, it is explained that the application controls the addition amount of calcium source in polyglutamic acid chelated calcium fertilizer to 70-80% of the total volume of polyglutamic acid fermentation liquid, and the obtained polyglutamic acid chelated calcium fertilizer is applied to tomato plants to obtain high-yield and high-quality tomatoes. Further comparison shows that after the polyglutamic acid chelated calcium fertilizer obtained in Examples 2-4 is used to fertilize tomato plants, the fruit setting rate of tomatoes can reach 83.7-86.7% (>80%), the yield can reach 28008-28546kg / mu (>28000kg / mu), and the VC content in tomatoes can reach 298.5-301.4mg / kg (>298.0mg / kg). Therefore, it is explained that the application further controls the addition amount of calcium source in polyglutamic acid chelated calcium fertilizer to 73-78% of the total volume of polyglutamic acid fermentation liquid, and the obtained polyglutamic acid chelated calcium fertilizer can make tomatoes have higher yield and better quality.

[0062] The test results of Example 3, Examples 6-9, and Comparative Example 3 show that with the increase in the amount of seaweed essence added, the fruit setting rate and yield of tomato plants both show a trend of first increasing and then decreasing; further comparison shows that after fertilizing tomato plants with the polyglutamic acid chelated calcium fertilizer obtained in Example 3 and Examples 6-7, the fruit setting rate of tomatoes can reach 81.7-86.7% (>80%), the yield can reach 28094-28546kg / mu (>28000kg / mu), and the VC content in tomatoes can reach 299.8-300.3mg / kg (>299.0mg / kg). Therefore, it is explained that the application further controls the amount of seaweed essence added in the polyglutamic acid chelated calcium fertilizer to 2-2.5% of the total weight of the polyglutamic acid fermentation liquid, and the use effect of the obtained polyglutamic acid chelated calcium fertilizer is better, which can make the yield of tomatoes higher.

[0063] The test results of Example 3, Example 10-15, and Comparative Example 4-5 show that after the tomato plants are fertilized with the polyglutamic acid chelated calcium fertilizer obtained in Example 3 and Example 10-15, the fruit setting rate of tomatoes is 80.8-86.7%, the yield is 27279-28546 kg / mu, and the VC content in tomatoes is 293.4-300.3 mg / kg; while after the tomato plants are fertilized with the polyglutamic acid chelated calcium fertilizer obtained in Comparative Example 4-5, the fruit setting rate of tomatoes is 69.2-71.5%, the yield is 25993-26867 kg / mu, and the VC content in tomatoes is 288.8-290.8 mg / kg. Therefore, it is explained that the application controls the stirring speed in step (3) to 300-500 r / min and the time to 60-120 min, and the use effect of the obtained polyglutamic acid chelated calcium fertilizer is good, and the tomato yield obtained is high.

[0064] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A polyglutamic acid chelated calcium fertilizer, characterized in that: The invention comprises the following components: polyglutamic acid fermentation liquid, a calcium source and seaweed extract; the amount of the calcium source is 70-80% of the total volume of the polyglutamic acid fermentation liquid; The content of polyglutamic acid in the polyglutamic acid fermentation broth is 30-45 g / L, and the molecular weight of polyglutamic acid is 1.8-2 million Da.

2. The polyglutamate chelated calcium fertilizer according to claim 1, characterized in that The amount of the calcium source is 73-78% of the total volume of the polyglutamic acid fermentation broth.

3. The polyglutamate chelated calcium fertilizer according to claim 1, characterized in that The preparation method of the polyglutamic acid fermentation liquid comprises the following steps: fermenting and culturing Bacillus subtilis in a fermentation medium to obtain the polyglutamic acid fermentation liquid; the fermentation medium formula is: 5-10 g / L glutamic acid, 5-10 g / L glucose, and 60-70 g / L yeast extract powder.

4. The polyglutamate chelated calcium fertilizer according to claim 1, characterized in that The calcium ion content in the calcium source is 160-190 g / L.

5. The polyglutamate chelated calcium fertilizer according to claim 1, characterized in that The preparation method of the calcium source comprises the following steps: adding nitric acid to shell powder or bone powder, and hydrolyzing for 48 hours; then adding composite bacteria thereto, and hydrolyzing at 30-40°C for 7-10 days, and then concentrating and filtering with an evaporator, and taking the supernatant to obtain the calcium source.

6. The polyglutamate chelated calcium fertilizer according to claim 5, characterized in that The live bacteria count of the composite bacteria is ≥100 billion / g, and the composite bacteria is a mixture of Bacillus subtilis, Bacillus licheniformis, lactic acid bacteria and Rhodopseudomonas palustris with a live bacteria count ratio of 2:2:3:

3.

7. The polyglutamate chelated calcium fertilizer according to claim 1, characterized in that Based on the volume of the polyglutamic acid fermentation liquid, the dosage of the seaweed essence is 15-30 g / L.

8. The method for preparing the polyglutamic acid chelated calcium fertilizer according to any one of claims 1 to 7, characterized in that: The following steps are involved: Under stirring, calcium source is gradually added to the polyglutamic acid fermentation liquid, and the stirring speed is controlled to be 300-500r / min for 60-120min to obtain a polyglutamic acid chelated calcium solution; and then seaweed extract is added to the polyglutamic acid chelated calcium solution, and stirred evenly to obtain a polyglutamic acid chelated calcium fertilizer.

9. Use of the polyglutamate chelated calcium fertilizer according to any one of claims 1 to 7 in the cultivation of fruits and vegetables.

10. The use according to claim 9, characterized in that: The application amount of the polyglutamic acid chelated calcium fertilizer is 8-12 kg / mu.

Images