Earthworm amino acid water-soluble fertilizer as well as preparation method and application thereof

Abstract

The invention provides an earthworm amino acid water-soluble fertilizer as well as a preparation method and application thereof. The earthworm amino acid water-soluble fertilizer is prepared from the following materials in parts by weight: 70 to 100 parts of ferrous sulfate, 8 to 14 parts of boric acid, 10 to 18 parts of potassium molybdate, 3 to 7 parts of monopotassium phosphate, 3 to 7 parts of manganese sulfate, 2 to 7 parts of zinc sulfate, 3 to 7 parts of copper sulfate, 2 to 5 parts of potassium chloride and 900 to 1100 parts of earthworm fermentation liquor. The nitrogen fertilizer in the amino acid water-soluble fertilizer exists in the form of amino acid molecules, can be easily absorbed and utilized by crops, can significantly reduce the conversion of the nitrogen fertilizer to an inorganic nitrogen form (such as nitrate), and effectively reduces the nitrate content of leaf vegetables. Besides, the proportion of phosphorus and potassium in the amino acid water-soluble fertilizer is determined according to the nutrient requirements of the leaf vegetables, and meanwhile, more comprehensive trace elements are added, so that the growth of the leaf vegetables can be promoted, and the taste of the leaf vegetables is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizers, and in particular to an earthworm amino acid water-soluble fertilizer and a preparation method and application thereof. Background Art

[0002] Leafy vegetables are an important vegetable crop in my country, accounting for about 25% of the total vegetable output. With the improvement of living standards, people are pursuing higher quality of leafy vegetables, such as good taste and low nitrate content. Studies have shown that leafy vegetables are more likely to accumulate nitrates, and their nitrate content is 1.6 times that of root vegetables, 14 times that of nightshades, and 21 times that of melons and vegetables. Nitrates themselves are non-toxic, but during long-term storage, they are easily reduced to nitrites, which reduce the oxygen-carrying capacity of the blood and cause hypoxia in the human body. And under the action of gastric acid, carcinogenic substances such as nitrosamines can be generated, threatening human health. Therefore, reducing the nitrate content in leafy vegetables is an important way to ensure food safety and human health.

[0003] At present, there are many ways to reduce the accumulation of nitrate in leafy vegetables, such as reducing the amount of inorganic nitrogen fertilizer, applying organic nitrogen fertilizer, inoculating microbial functional bacteria, applying nitrogen fertilizer inhibitors, etc. Among them, the effect of inoculating microbial functional bacteria in reducing nitrate is slow, and the application of nitrogen fertilizer inhibitors is greatly affected by the amount of addition, the time of addition and the soil environment. Therefore, reducing the amount of inorganic nitrogen fertilizer and applying organic nitrogen fertilizer is an important way to reduce the nitrate content in leafy vegetables. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an earthworm amino acid water-soluble fertilizer and a preparation method and application thereof.

[0005] The scheme of the present invention includes the following aspects:

[0006] A water-soluble earthworm amino acid fertilizer comprises the following materials in parts by weight: 70-100 parts of ferrous sulfate, 8-14 parts of boric acid, 10-18 parts of potassium molybdate, 3-7 parts of potassium dihydrogen phosphate, 3-7 parts of manganese sulfate, 2-7 parts of zinc sulfate, 3-7 parts of copper sulfate, 2-5 parts of potassium chloride and 900-1100 parts of earthworm fermentation liquid, for supplementing the elements required by leafy vegetables.

[0007] Preferably, the following materials are included in parts by weight: 80-100 parts of ferrous sulfate, 8-12 parts of boric acid, 11-17 parts of potassium molybdate, 4-6 parts of potassium dihydrogen phosphate, 4-6 parts of manganese sulfate, 4-6 parts of zinc sulfate, 4-6 parts of copper sulfate, 2-4 parts of potassium chloride and 900-1100 parts of earthworm fermentation liquid.

[0008] Preferably, the addition ratio of phosphorus to potassium is 1:2.5-6.

[0009] Preferably, the preparation steps of earthworm fermentation liquid include the following:

[0010] (1) starving earthworms for 6 to 10 hours to obtain hungry earthworms, so as to make them digest the sediment in their bodies and prepare foliar fertilizer that can be directly absorbed;

[0011] (2) mincing the hungry earthworms, placing them in a fermentation tank, and adding deionized water to allow their autolytic enzymes to take effect and decompose the starch in their bodies;

[0012] (3) adding glycine, L-leucine, L-threonine and L-tryptophan to obtain amino acid-rich earthworms;

[0013] (4) Protease and lipase are added to amino acid-rich earthworms for constant temperature fermentation. Protease is used to decompose protein into amino acids that can be directly absorbed by leafy vegetables. The presence of nitrogen fertilizer in the form of amino acids can significantly reduce the conversion of nitrogen fertilizer into inorganic nitrogen forms (such as nitrates), effectively reducing the nitrate content of leafy vegetables. Lipase is used to decompose fat into fatty acids and glycerol that can be directly absorbed by leafy vegetables. At the same time, lipase and protease work synergistically to decompose protein more fully.

[0014] (5) After filtering, check the decomposition status, take the filter residue for secondary fermentation, and filter again after fermentation. The secondary filtration allows the mud and sand in the earthworms to be fully filtered out, and the secondary fermentation ensures that the earthworms are completely decomposed;

[0015] (6) combining the filtrates from the two filtrations to obtain the hungry earthworm fermentation liquid;

[0016] (7) Adding complex amino acids and L-arginine to the fermentation liquid of hungry earthworms makes the pH neutral to alkaline. The soil where leafy vegetables grow is generally acidic. Using neutral to alkaline fertilizers can reduce the loss of fertilizer nutrients and improve fertilizer utilization.

[0017] Earthworms are rich in protein, amino acids, fats, minerals, vitamins and trace elements. The protein content, fat content and carbohydrates account for 53.5% to 65.1%, 4.4% to 17.38% and 11% to 17.4% of their dry weight, respectively. The present invention finds that the use of protease and lipase together can synergistically make the protein decomposition effect more complete. The earthworm amino acid water-soluble fertilizer provided by the present invention uses earthworms as raw materials, and nitrogen fertilizer exists in the form of amino acid molecules. The types and proportions of amino acids ensure that the fertilizer is neutral and alkaline. Selecting alkaline fertilizers on acidic soils and acidic fertilizers on alkaline soils is one of the important principles of rational fertilization to reduce the loss of fertilizer nutrients, improve fertilizer utilization, and give full play to the fertilizer effect. At the same time, it can also significantly reduce the conversion of nitrogen fertilizers to inorganic nitrogen forms (such as nitrates), and effectively reduce the nitrate content of leafy vegetables.

[0018] The present invention adopts a secondary fermentation method to ensure that the earthworm protein is fully decomposed, and secondary filtration is performed to ensure that the residual sand in the earthworm body is completely filtered out, and can be directly absorbed by plants as leaf fertilizer. In addition, the phosphorus and potassium ratios in the amino acid water-soluble fertilizer of the present invention are determined according to the nutrient requirements of leaf vegetables, and a relatively comprehensive trace element is added at the same time, which can promote the growth of leaf vegetables and improve the taste of leaf vegetables.

[0019] Preferably, the earthworms are placed at a density of 5-6 kg / m2.

[0020] Preferably, the mass ratio of the hungry earthworms to water is 2.5-3.5:1; the pH value is adjusted to 6.5-7.5, and the fermentation is carried out at a constant temperature of 26-28°C for 9-10 hours, during which the mixture is stirred 2-5 times.

[0021] Preferably, medium-coarse filter paper is used for the first filtration, fine filter paper is used for the second filtration, and the secondary fermentation is carried out at a constant temperature of 26-28° C. for 2-5 hours.

[0022] Preferably, the mass ratio of the compound amino acids, glycine, L-leucine, L-threonine, L-tryptophan and L-arginine is 12-13: 3.5-4.5: 0.8-1.2: 2.5-3.5: 7.5-8.5: 1.4-1.8.

[0023] Preferably, the added amount of the protease and lipase is 1%-2% of the mass of the hungry earthworms; the mass ratio of the protease to the lipase is 1.8-2.2:1.

[0024] Preferably, the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine added accounts for 60% to 70% of the total amount of free amino acids.

[0025] Preferably, the composite amino acids include at least 15 of threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, tryptophan, aspartic acid, cystine, cysteine, and alanine.

[0026] Preferably, the earthworm fermentation liquid is mixed with ferrous sulfate, boric acid, potassium molybdate, potassium dihydrogen phosphate, manganese sulfate, zinc sulfate, copper sulfate and potassium chloride to obtain the earthworm amino acid water-soluble fertilizer.

[0027] Preferably, the earthworm amino acid water-soluble fertilizer is used in the cultivation of pakchoi.

[0028] Preferably, the earthworm amino acid water-soluble fertilizer is used to increase the yield of Chinese cabbage, the soluble sugar content or reduce the nitrate content.

[0029] Preferably, 8 to 12 days after the Chinese cabbage sprouts, the above-mentioned earthworm amino acid water-soluble fertilizer is used for topdressing. After diluting the earthworm amino acid water-soluble fertilizer by 800 to 1000 times, topdressing is performed every 5 to 7 days, for a total of 2 to 4 times.

[0030] Beneficial effects achieved by the present invention:

[0031] 1. The present invention prepares amino acid water-soluble fertilizer by scientifically preparing earthworm fermentation liquid and ferrous sulfate, boric acid, potassium molybdate, potassium dihydrogen phosphate, manganese sulfate, zinc sulfate, copper sulfate and potassium chloride. The nitrogen fertilizer in the amino acid water-soluble fertilizer exists in the form of amino acid molecules, which is easy to be absorbed and utilized by crops. At the same time, it can also significantly reduce the conversion of nitrogen fertilizer into inorganic nitrogen form (such as nitrate), and can reduce the nitrate content of tall-legged sweet cabbage, black-leafed Chinese cabbage and short-legged black-leafed sweet cabbage by 34.15%, 31.41% and 32.39% respectively.

[0032] 2. In the amino acid water-soluble fertilizer of the present invention, the phosphorus and potassium ratios in ferrous sulfate, boric acid, potassium molybdate, potassium dihydrogen phosphate, manganese sulfate, zinc sulfate, copper sulfate and potassium chloride can be adjusted according to the nutrient requirements of leafy vegetables. At the same time, the earthworm fermentation liquid is matched with comprehensive trace elements to fully ensure the healthy growth, high yield and high quality of leafy vegetables, promote the growth of tall-legged sweet cabbage, black-leafed Chinese cabbage and short-legged black-leafed sweet cabbage, increase their yields by 43.18%, 46.31% and 47.30% respectively, and increase the soluble sugar content by 50.18%, 46.14% and 51.15% respectively, significantly improve the taste of leafy vegetables, and improve the quality of leafy vegetables.

[0033] 3. The preparation method of earthworm fermentation liquid provided by the present invention uses hungry earthworms to remove the mud and sand in the earthworms' bodies, adopts the secondary fermentation process, can fully decompose the earthworms, and uses medium-coarse filter paper and fine filter paper successively during filtration, thereby achieving the goal of improving the extraction efficiency while ensuring the experimental process, and preparing an amino acid water-soluble fertilizer that can be used as a foliar fertilizer, thereby improving the cultivation quality of leafy vegetables, especially tall-legged sweet cabbage, black-leafed Chinese cabbage, and short-legged black-leafed sweet cabbage. DETAILED DESCRIPTION

[0034] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0035] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0036] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0037] The protease used in the embodiment of the present invention is papain, and the enzyme activities of lipase and papain are both 100,000 U / g.

[0038] Example 1

[0039] A water-soluble earthworm amino acid fertilizer is composed of the following materials in parts by weight: 80 parts of ferrous sulfate, 8 parts of boric acid, 11 parts of potassium molybdate, 4 parts of potassium dihydrogen phosphate, 4 parts of manganese sulfate, 4 parts of zinc sulfate, 4 parts of copper sulfate, 2 parts of potassium chloride, and 900 parts of earthworm fermentation liquid, wherein the ratio of phosphorus to potassium added is 1:2.96.

[0040] The preparation steps of earthworm fermentation liquid are as follows:

[0041] (1) earthworms were placed in a box at a density of 5 kg per square meter, the indoor temperature was adjusted to 22°C, and starvation culture was performed for 6 hours, after which the earthworms were taken out;

[0042] (2) Put the minced earthworms into a fermentation tank, add deionized water, the mass ratio of earthworms to deionized water is 2.5:1, then add glycine, L-leucine, L-threonine, L-tryptophan in a mass ratio of 3.5:0.8:2.5:7.5, and then add papain and lipase in a mass ratio of 1.8:1. The enzyme addition ratio is 1.066% of the total material mass. Adjust the pH value to 6.8, and ferment at a constant temperature of 26°C for 9 hours, stir twice during the fermentation, filter with medium-coarse filter paper after fermentation, and take the filter residue for secondary fermentation at 26°C for 2 hours;

[0043] (3) After the secondary fermentation, filter with fine filter paper, combine the two filtrates, and then add a composite amino acid composed of threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, tryptophan and L-arginine in a mass ratio of 12:1.4 to the filtrate, stir evenly, ensure that the pH of the fermentation liquid is 7-8, ensure that the mass ratio of the composite amino acid, glycine, L-leucine, L-threonine, L-tryptophan and L-arginine is 12:3.5:0.8:2.5:7.5:1.4, and ensure that the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine in the fermentation liquid accounts for 60% of the total amount of free amino acids, which is the earthworm fermentation liquid.

[0044] Example 2

[0045] A water-soluble earthworm amino acid fertilizer is composed of the following materials in parts by weight: 90 parts of ferrous sulfate, 10 parts of boric acid, 14 parts of potassium molybdate, 5 parts of potassium dihydrogen phosphate, 5 parts of manganese sulfate, 5 parts of zinc sulfate, 5 parts of copper sulfate, 3 parts of potassium chloride, and 1000 parts of earthworm fermentation liquid, wherein the ratio of phosphorus to potassium added is 1:3.08.

[0046] The preparation steps of earthworm fermentation liquid are as follows:

[0047] (1) earthworms were placed in a box at a density of 5.5 kg per square meter, the indoor temperature was adjusted to 22°C, and starvation culture was performed for 8 hours, after which the earthworms were taken out;

[0048] (2) Put the minced earthworms into a fermentation tank, add deionized water, the mass ratio of earthworms to deionized water is 3:1, then add glycine, L-leucine, L-threonine, L-tryptophan in a mass ratio of 4:1:3:8, and then add papain and lipase in a mass ratio of 2:1. The enzyme addition ratio is 1.3% of the total material mass. Adjust the pH value to 7 and ferment at a constant temperature of 27°C for 9.5 hours, stir 3 times during the fermentation, filter with medium-coarse filter paper after fermentation, and take the filter residue for secondary fermentation at 28°C for 4 hours;

[0049] (3) After the secondary fermentation, filter with fine filter paper, combine the two filtrates, and then add a composite amino acid composed of threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, tryptophan, aspartic acid, cystine, cysteine, and alanine and L-arginine in a mass ratio of 12.5:1.6 to the filtrate, stir evenly, ensure that the pH of the fermentation liquid is 7-8, ensure that the mass ratio of the composite amino acid, glycine, L-leucine, L-threonine, L-tryptophan and L-arginine is 12.5:4:1:3:8:1.6, and ensure that the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine in the fermentation liquid accounts for 65% of the total amount of free amino acids, which is the earthworm fermentation liquid.

[0050] Example 3

[0051] A water-soluble earthworm amino acid fertilizer is composed of the following materials in parts by weight: 100 parts of ferrous sulfate, 12 parts of boric acid, 17 parts of potassium molybdate, 6 parts of potassium dihydrogen phosphate, 6 parts of manganese sulfate, 6 parts of zinc sulfate, 6 parts of copper sulfate, 4 parts of potassium chloride, and 1,100 parts of earthworm fermentation liquid, wherein the ratio of phosphorus to potassium added is 1:3.21.

[0052] The preparation steps of earthworm fermentation liquid are as follows:

[0053] (1) earthworms were placed in a box at a density of 6 kg per square meter, the indoor temperature was adjusted to 22°C, and starvation culture was performed for 10 hours, after which the earthworms were taken out;

[0054] (2) Put the minced earthworms into a fermentation tank, add deionized water, the mass ratio of earthworms to deionized water is 3.5:1, then add glycine, L-leucine, L-threonine, L-tryptophan in a mass ratio of 4.5:1.2:3.5:8.5, and then add papain and lipase in a mass ratio of 2.2:1. The enzyme addition ratio is 1.6% of the total material mass, adjust the pH value to 7.2, and ferment at a constant temperature of 28°C for 10 hours, stir 5 times during the fermentation, filter with medium-coarse filter paper after fermentation, and take the filter residue for secondary fermentation at 28°C for 5 hours;

[0055] (3) After the secondary fermentation, filter with fine filter paper, combine the two filtrates, and then add a composite amino acid composed of threonine, serine, glutamic acid, proline, alanine, valine, methionine, isoleucine, tyrosine, phenylalanine, lysine, histidine, aspartic acid, cystine, cysteine, and alanine and L-arginine in a mass ratio of 13:1.8 to the filtrate, stir evenly, ensure that the pH of the fermentation liquid is 7-8, ensure that the mass ratio of the composite amino acid, glycine, L-leucine, L-threonine, L-tryptophan and L-arginine is 13:4.5:1.2:3.5:8.5:1.8, and ensure that the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine in the fermentation liquid accounts for 70% of the total amount of free amino acids, which is the earthworm fermentation liquid.

[0056] Test example:

[0057] In order to further illustrate the promotion and application value of the earthworm amino acid water-soluble fertilizer of the present invention, the functional fertilizers prepared in the examples and comparative examples were tested for fertilizer efficiency on pakchoi.

[0058] Test materials: Chinese cabbage, tall sweet cabbage, black-leaf Chinese cabbage, short black-leaf sweet cabbage

[0059] Experimental design: The experimental design includes 27 treatments, 3 replicates per treatment, and 2 m 2 , randomized block arrangement. The specific experimental design is as follows.

[0060] Treatment 1: Functional fertilizer prepared in Example 1

[0061] Treatment 2: Functional fertilizer prepared in Example 2

[0062] Treatment 3: Functional fertilizer prepared in Example 3

[0063] Control 1-1: The ratio of phosphorus and potassium added in treatment 1 was greater than 1:1.40

[0064] Control 1-2: The ratio of phosphorus and potassium addition in treatment 2 was greater than 1:1.40

[0065] Control 1-3: The ratio of phosphorus and potassium addition in treatment 3 was greater than 1:1.40

[0066] Control 2-1: The ratio of phosphorus and potassium added in treatment 1 was greater than 1:1.60

[0067] Control 2-2: The ratio of phosphorus and potassium added in treatment 2 was greater than 1:1.60

[0068] Control 2-3: The ratio of phosphorus and potassium addition in treatment 3 was greater than 1:1.60

[0069] Control 3-1: No earthworm fermentation liquid was added to treatment 1

[0070] Control 3-2: No earthworm fermentation liquid was added to treatment 2

[0071] Control 3-3: No earthworm fermentation liquid was added in treatment 3

[0072] Control 4-1: Treatment 1 with sterilized earthworm fermentation liquid

[0073] Control 4-2: Treatment 2 with sterilized earthworm fermentation liquid

[0074] Control 4-3: Treatment 3 with sterilized earthworm fermentation liquid

[0075] Control 5-1: The total amount of glycine, L-leucine, L-threonine, L-tryptophan, and L-arginine in treatment 1 accounted for less than 60% of the total amount of free amino acids

[0076] Control 5-2: The total amount of glycine, L-leucine, L-threonine, L-tryptophan, and L-arginine in treatment 2 accounted for less than 60% of the total amount of free amino acids

[0077] Control 5-3: The total amount of glycine, L-leucine, L-threonine, L-tryptophan, and L-arginine in treatment 3 accounted for less than 60% of the total amount of free amino acids

[0078] Control 6-1: The total amount of glycine, L-leucine, L-threonine, L-tryptophan, and L-arginine in treatment 1 accounted for more than 70% of the total amount of free amino acids

[0079] Control 6-2: The total amount of glycine, L-leucine, L-threonine, L-tryptophan, and L-arginine in treatment 2 accounted for more than 70% of the total amount of free amino acids

[0080] Control 6-3: The total amount of glycine, L-leucine, L-threonine, L-tryptophan, and L-arginine in treatment 3 accounted for more than 70% of the total amount of free amino acids

[0081] Control 7-1: No compound amino acids and L-arginine were added to treatment 1

[0082] Control 7-2: No compound amino acids and L-arginine were added to treatment 2

[0083] Control 7-3: No compound amino acids and L-arginine were added to treatment 3

[0084] Absolute control 1: conventional amino acid water-soluble fertilizer, the total amount of free amino acids is the same as treatment 1

[0085] Absolute control 2: conventional amino acid water-soluble fertilizer, the total amount of free amino acids is the same as treatment 2

[0086] Absolute control 3: conventional amino acid water-soluble fertilizer, the total amount of free amino acids is the same as treatment 3

[0087] On the 10th day after the leafy vegetables sprouted, the amino acid water-soluble fertilizer prepared for each treatment was applied according to the experimental design, diluted 800-1000 times and sprayed on the leaves, and then applied once every 5-7 days, for a total of 3 times. Except for the topdressing during the growth period of the leafy vegetables, the water, fertilizer and pesticide management of each treatment was the same. At harvest, the yield of leafy vegetables of different varieties was counted, and their nitrate and soluble sugar content was determined. The specific data are shown in Table 1-3.

[0088] Table 1 Effect of fertilization treatment on yield of different varieties of leafy vegetables (kg / area)

[0089]

[0090]

[0091] Note: Different capital letters in the table indicate significant differences among treatments (P<0.05), and different lowercase letters indicate significant differences within treatments (P<0.05), the same below

[0092] As can be seen from Table 1, compared with the addition ratio of phosphorus and potassium greater than 1:1.40 (control 1-1 to 1-3), the addition ratio of phosphorus and potassium greater than 1:1.60 (control 2-1 to 2-3), no addition of earthworm fermentation liquid (control 3-1 to 3-3), addition of sterilized earthworm fermentation liquid (control 4-1 to 4-3), the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine in the fertilizer accounting for less than 60% of the total amount of free amino acids (control 5-1 to 5-3) or greater than 70% (control 6-1 to 6-3), no addition of composite amino acids and L-arginine (control 7-1 to 7-3) and conventional amino acid water-soluble fertilizer (absolute control 1 to 3), the application of the earthworm amino acid water-soluble fertilizer prepared by the present invention (treatment 1 to 3), the yield of different varieties of leafy vegetables was significantly increased, and the highest increase was 43.18%, 46.31% and 47.30%, respectively.

[0093] Table 2 Effect of fertilization treatment on soluble sugar content of different varieties of leafy vegetables (%)

[0094]

[0095]

[0096] As can be seen from Table 2, compared with the addition ratio of phosphorus and potassium greater than 1:1.40 (control 1-1 to 1-3), the addition ratio of phosphorus and potassium greater than 1:1.60 (control 2-1 to 2-3), no addition of earthworm fermentation liquid (control 3-1 to 3-3), addition of sterilized earthworm fermentation liquid (control 4-1 to 4-3), the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine in the fertilizer accounting for less than 60% of the total amount of free amino acids (control 5-1 to 5-3) or greater than 70% (control 6-1 to 6-3), no addition of composite amino acids and L-arginine (control 7-1 to 7-3) and conventional amino acid water-soluble fertilizer (absolute control 1 to 3), the application of the earthworm amino acid water-soluble fertilizer prepared by the present invention (treatment 1 to 3), the soluble sugar content of different varieties of leafy vegetables was significantly increased, and the highest increase was 50.18%, 46.14% and 51.15%, respectively.

[0097] Table 3 Effect of fertilization treatment on nitrate content of different varieties of leafy vegetables (mg / kg)

[0098]

[0099]

[0100] As can be seen from Table 3, compared with the addition ratio of phosphorus and potassium greater than 1:1.40 (control 1-1 to 1-3), the addition ratio of phosphorus and potassium greater than 1:1.60 (control 2-1 to 2-3), no addition of earthworm fermentation liquid (control 3-1 to 3-3), addition of sterilized earthworm fermentation liquid (control 4-1 to 4-3), the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine in the fertilizer accounting for less than 60% (control 5-1 to 5-3) or greater than 70% (control 6-1 to 6-3) of the total amount of free amino acids, no addition of composite amino acids and L-arginine (control 7-1 to 7-3) and conventional amino acid water-soluble fertilizer (absolute control 1 to 3), the application of the earthworm amino acid water-soluble fertilizer prepared by the present invention (treatment 1 to 3), the nitrate content of different varieties of leafy vegetables was significantly reduced, and the maximum reduction was 34.15%, 31.41% and 32.39%, respectively.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A water-soluble earthworm amino acid fertilizer, characterized in that: The invention comprises the following materials in parts by weight: 70-100 parts of ferrous sulfate, 8-14 parts of boric acid, 10-18 parts of potassium molybdate, 3-7 parts of potassium dihydrogen phosphate, 3-7 parts of manganese sulfate, 2-7 parts of zinc sulfate, 3-7 parts of copper sulfate, 2-5 parts of potassium chloride and 900-1100 parts of earthworm fermentation liquid.

2. The earthworm amino acid water-soluble fertilizer according to claim 1, characterized in that: The invention comprises the following materials in parts by weight: 80-100 parts of ferrous sulfate, 8-12 parts of boric acid, 11-17 parts of potassium molybdate, 4-6 parts of potassium dihydrogen phosphate, 4-6 parts of manganese sulfate, 4-6 parts of zinc sulfate, 4-6 parts of copper sulfate, 2-4 parts of potassium chloride and 900-1100 parts of earthworm fermentation liquid; the adding ratio of phosphorus to potassium is 1:2.5-6.

3. The earthworm amino acid water-soluble fertilizer according to claim 1 or 2, characterized in that: The preparation steps of the earthworm fermentation liquid include the following: (1) Starving earthworms for 6 to 10 hours to obtain hungry earthworms; (2) mincing the hungry earthworms, adding water, and adding glycine, L-leucine, L-threonine and L-tryptophan to obtain amino acid-rich earthworms; (3) adding protease and lipase to the amino acid-rich earthworms, adjusting the pH, and performing constant temperature fermentation; (4) performing a first filtration after constant temperature fermentation, taking the filter residue for a second fermentation, and performing a second filtration after the second fermentation; (5) combining the filtrates from the two filtrations to obtain hungry earthworm fermentation liquid; (6) Adding complex amino acids and L-arginine to the fermentation liquid of hungry earthworms to adjust the pH to neutral or alkaline, thereby obtaining earthworm fermentation liquid.

4. The earthworm amino acid water-soluble fertilizer according to claim 3, characterized in that: In step (1), the earthworms are placed at a density of 5-6 kg / m2; In step (2), the mass ratio of the hungry earthworms to water is 2.5 to 3.5:1; In step (3), the pH value is adjusted to 6.5-7.5, and the fermentation is carried out at a constant temperature of 26-28° C. for 9-10 hours, during which the mixture is stirred 2-5 times; In step (4), medium-coarse filter paper is used for the first filtration, fine filter paper is used for the second filtration, and the secondary fermentation is carried out at a constant temperature of 26-28° C. for 2-5 hours; In steps (2) and (6), the mass ratio of the compound amino acids, glycine, L-leucine, L-threonine, L-tryptophan and L-arginine is 12-13: 3.5-4.5: 0.8-1.2: 2.5-3.5: 7.5-8.5: 1.4-1.

8.

5. The earthworm amino acid water-soluble fertilizer according to claim 3, characterized in that: In step (3), the amount of the protease and lipase added is 1%-2% of the mass of the hungry earthworms; the mass ratio of the protease to the lipase is 1.8-2.2:1; In step (2), the total amount of glycine, L-leucine, L-threonine, L-tryptophan and L-arginine added accounts for 60% to 70% of the total amount of free amino acids.

6. The earthworm amino acid water-soluble fertilizer according to claim 3, characterized in that: The composite amino acids include at least 15 of threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, tryptophan, aspartic acid, cystine, cysteine, and alanine.

7. The method for preparing the earthworm amino acid water-soluble fertilizer according to any one of claims 1 to 6, characterized in that: The earthworm fermentation liquid is mixed with ferrous sulfate, boric acid, potassium molybdate, potassium dihydrogen phosphate, manganese sulfate, zinc sulfate, copper sulfate and potassium chloride to obtain the earthworm amino acid water-soluble fertilizer.

8. Use of the earthworm amino acid water-soluble fertilizer according to any one of claims 1 to 6 in the cultivation of pakchoi.

9. The use according to claim 8, characterized in that: The earthworm amino acid water-soluble fertilizer is used to increase the yield of Chinese cabbage, the soluble sugar content or reduce the nitrate content.

10. A method for reducing the nitrate content of pakchoi, characterized in that: 8 to 12 days after the Chinese cabbage sprouts, use the earthworm amino acid water-soluble fertilizer described in any one of claims 1 to 6 for topdressing. After diluting the earthworm amino acid water-soluble fertilizer 800 to 1000 times, topdress once every 5 to 7 days, for a total of 2 to 4 times.

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