CN115417720A - Liquid compound microbial fertilizer with long shelf life and no barrel expansion and preparation method thereof - Google Patents

Abstract

The invention discloses a liquid compound microbial fertilizer with long shelf life and no barrel expansion and a preparation method thereof, wherein the liquid compound microbial fertilizer comprises the following components in parts by mass: 40-50 parts of bio-control microbial inoculum, 30-40 parts of buffer substance, 12.5-16.5 parts of organic substance, 0.15-0.2 part of preservative, 3-5 parts of inorganic salt and 0.3-0.5 part of stabilizer; wherein the buffer substance is yeast fermentation liquid and lactobacillus fermentation liquid, and the antiseptic is sodium benzoate and potassium sorbate. The invention uses the preservative and the buffer substance to lead the strains to be in a dormant state and a restrained state, the activity of the strains is reduced, the generation of gas is reduced, and the barrel is not expanded. The preservative and the buffering substance used in the invention have a synergistic effect, the preservative plays a role in inhibiting the growth and the propagation of strains in the liquid fertilizer, and the buffering substance plays a role in regulating the change of pH value and stabilizing the liquid environment.

Description

Liquid compound microbial fertilizer with long shelf life and no barrel expansion and preparation method thereof

Technical Field

The invention relates to the technical field of soil fertilizers, in particular to a liquid compound microbial fertilizer with long shelf life and no barrel expansion and a preparation method thereof.

Background

The compound microbial fertilizer is a biological fertilizer containing microorganisms, inorganic nutrients and organic substances, can effectively promote the growth of crops, promote the development of root systems, improve the microecology of soil and restore the soil, and conforms to the current national policy guidance of reducing the dosage of pesticides and fertilizers and replacing the fertilizers with the organic fertilizers.

At present, most microbial fertilizers are stored in a solid state, the survival rate is guaranteed to a certain extent, but compared with liquid microbial inoculums, more equipment, technology and personnel are needed for producing solid products, and the application convenience and effect are not as good as those of liquid products.

The microbial fertilizer is a biological fertilizer prepared by industrially culturing and fermenting one or more beneficial microorganisms, and most of the microbial agents used in the microbial fertilizer are prepared by liquid fermentation.

The requirement of the microbial bacteria on the growth environment is low, and the microbial bacteria are active, ferment and reproduce to generate gas in the storage and transportation processes, so that the phenomenon of flatulence and barrel expansion occurs. Meanwhile, part of strains die, the content and the activity of the microbial bacteria are reduced, the product effect is reduced, and the quality guarantee period is short.

Disclosure of Invention

Aiming at the prior art, the liquid microbial fertilizer, in particular to a composite microbial fertilizer product rich in organic and inorganic nutrients, has short storage time and is easy to generate gas expansion barrels, and the invention aims to provide the liquid composite microbial fertilizer with long shelf life and no barrel expansion and the preparation method thereof. The invention uses the preservative and the buffer substance to lead the strains to be in a dormant state and a restrained state, the activity of the strains is reduced, the generation of gas is reduced, and the barrel is not expanded.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a liquid compound microbial fertilizer with a long shelf life and no barrel expansion, which comprises the following components in parts by mass:

40-50 parts of biocontrol microbial inoculum, 30-40 parts of buffer substance, 12.5-16.5 parts of organic substance, 0.15-0.2 part of preservative, 3-5 parts of inorganic salt and 0.3-0.5 part of stabilizer;

the biocontrol microbial inoculum is bacillus fermentation liquor; the buffer substance comprises 15 to 20 parts of yeast fermentation liquor and 15 to 20 parts of lactobacillus fermentation liquor; the preservative comprises 0.05 to 0.08 portion of sodium benzoate and 0.1 to 0.12 portion of potassium sorbate.

Preferably, the bacillus fermentation liquid is one or more of bacillus subtilis fermentation liquid, bacillus licheniformis fermentation liquid and bacillus amyloliquefaciens fermentation liquid.

Preferably, the number of viable bacteria in the biocontrol microbial inoculum is 2 multiplied by 10 ⁹ -5×10 ¹⁰ CFU/ml。

Preferably, the yeast fermentation liquid is a saccharomyces cerevisiae fermentation liquid, and the lactobacillus fermentation liquid is an acidophilic lactobacillus fermentation liquid.

Preferably, the number of viable bacteria in the buffer substance is 1 × 10 ⁸ -1×10 ¹¹ CFU/ml。

Preferably, the organic matters comprise 4-5 parts of mineral source potassium fulvate, 4-5 parts of molasses liquid and 4.5-6.5 parts of corn steep liquor.

More preferably, the components of the mineral potassium fulvate comprise humic acid and fulvic acid, wherein the content of the humic acid is more than or equal to 30g/L, and the content of the fulvic acid is more than or equal to 20g/L.

Preferably, the inorganic salt is one or more of urea, urea ammonium nitrate solution, monopotassium phosphate, ammonium polyphosphate, monoammonium phosphate, diammonium phosphate, potassium chloride, potassium sulfate and potassium nitrate.

Preferably, the stabilizer is one or more of sodium dodecyl sulfate, methyl amyl alcohol, cellulose derivatives, carboxymethyl cellulose and vitamin C.

The invention also provides a preparation method of the liquid compound microbial fertilizer with long shelf life and no barrel expansion, which comprises the following steps:

(1) Mixing 40-50 parts of bacillus fermentation liquor, 15-20 parts of yeast fermentation liquor, 15-20 parts of lactobacillus fermentation liquor, 4-5 parts of molasses liquid, 4.5-6.5 parts of corn steep liquor, 0.05-0.08 part of sodium benzoate and 0.1-0.12 part of potassium sorbate, and stirring for 5-10min to obtain solution A;

(2) Adding 3-5 parts of inorganic salt into the solution A, and stirring for 10-15min to obtain solution B;

(3) Adding 4-5 parts of mineral source fulvic acid potassium into the solution B, and stirring for 5-10min to obtain solution C;

(4) And adding 0.3-0.5 part of stabilizer into the solution C, and stirring for 15-25min to obtain the liquid composite microbial fertilizer.

The Bacillus subtilis (Bacillus subtilis) used in the invention is purchased from China agricultural microorganism strain preservation management center, and the preservation number is ACCC 60429; the Bacillus licheniformis (Bacillus licheniformis) is purchased from China agricultural microbial strain preservation management center with the preservation number of ACCC 19946; the Bacillus amyloliquefaciens (Bacillus amyloliquefaciens) is purchased from China agricultural microorganism strain preservation management center with the preservation number of ACCC 19746; the Saccharomyces cerevisiae (Saccharomyces cerevisiae) is purchased from China agricultural microbial strain preservation management center, and the preservation number is ACCC 21177; the Lactobacillus acidophilus (Lactobacillus acidophilus) is purchased from China agricultural microorganism culture collection center with the collection number of ACCC 10637.

The mineral potassium fulvate, the molasses liquid and the corn steep liquor have the effects of promoting roots and improving soil, and the metabolites in the yeast fermentation liquor and the lactobacillus fermentation liquor also have the effective root-promoting function; the bacillus fermentation liquor has the function of preventing and treating soil-borne diseases, and the inorganic salt provides nutrient components for crops and supplements nitrogen, phosphorus and potassium nutrients. The stabilizer enables nutrients needed by crops to be suspended in the liquid fertilizer, production precipitation is prevented, and the liquid fertilizer cannot be layered after being placed for a long time.

The invention solves the problem of barrel expansion of the liquid fertilizer by utilizing the combined action of the buffer substance and the preservative, and the preservative plays a role in inhibiting the growth and the propagation of strains in the liquid fertilizer, so that the strains are in an inhibition state, the activity is low, and gas is not generated any more; although the yeast and the lactic acid bacteria can be inhibited from breeding by the preservative, the invention mainly utilizes the buffer substances generated in the yeast fermentation liquor and the lactic acid bacteria fermentation liquor, the buffer substances are not generated after the yeast and the lactic acid bacteria enter the liquid fertilizer, and mainly utilizes the lactic acid and the lactate generated by the yeast and the lactic acid bacteria to form a buffer pair, and the buffer pair is subjected to acid regulation and alkali regulation in advance when meeting acid, so that the effects of regulating the pH value change and stabilizing the liquid environment are achieved, the strain is in a dormant state, the activity is low, the amount of generated gas is small, and the barrel does not expand. The preservative and the buffer substance used in the invention have a synergistic effect on solving the problem of liquid fertilizer expansion.

The invention has the beneficial effects that:

the liquid fertilizer solves the problem of barrel expansion by utilizing the combined action of the buffer substance and the preservative, the preservative and the buffer substance have the synergistic promotion effect, the preservative plays a role in inhibiting the growth and the propagation of strains in the liquid fertilizer, and the buffer substance utilizes lactic acid and lactate generated by the buffer substance to form a buffer pair, and the buffer pair regulates acid when meeting acid and alkali when meeting alkali, thereby playing roles in regulating the change of pH value and stabilizing the liquid environment. The invention uses the preservative and the buffer substance to ensure that the strains are in a dormant state and a restrained state, the activity of the strains is reduced, the generation of gas is reduced, and the barrel is not expanded. When the liquid fertilizer is used, the liquid fertilizer is flushed by adding water, the concentration of the preservative is reduced, the pH value is changed, the effect of inhibiting the strains is not achieved, and the strains are released from a dormant state and an inhibited state to play respective effects.

Organic matters in the liquid composite microbial fertilizer and metabolites of lactic acid bacteria and saccharomycetes have the effects of promoting crop rooting and improving soil, and the growth-promoting microbial inoculum has the effect of preventing and treating various soil-borne diseases.

The liquid compound microbial fertilizer can provide nutrient components for crops, has the effects of promoting the rooting of the crops, improving soil and preventing and treating diseases, and has long quality guarantee period and difficult barrel expansion.

Drawings

FIG. 1: the number of bacteria in each group in example 1 of the present invention was varied;

FIG. 2: the number of bacteria was changed in example 2 of the present invention and comparative examples 1 to 2;

FIG. 3: the growth of the mycoderm of each group in example 1 of the present invention;

FIG. 4: the overflow condition of each group in example 1 of the present invention;

FIG. 5: the invention is a schematic diagram of an inflation experiment.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

As described in the background technology, the liquid microbial fertilizer, especially the composite microbial fertilizer product rich in organic and inorganic nutrients, has short storage time and is easy to produce air swelling barrels, and based on the liquid microbial fertilizer, the invention provides the liquid composite microbial fertilizer which has long shelf life and does not swell the barrels, and the liquid composite microbial fertilizer comprises the following components in parts by mass:

40-50 parts of bio-control microbial inoculum, 30-40 parts of buffer substance, 12.5-16.5 parts of organic substance, 0.15-0.2 part of preservative, 3-5 parts of inorganic salt and 0.3-0.5 part of stabilizer;

the biocontrol microbial inoculum is bacillus fermentation liquor; the buffer substance comprises 15 to 20 parts of yeast fermentation liquor and 15 to 20 parts of lactobacillus fermentation liquor; the preservative comprises 0.05 to 0.08 portion of sodium benzoate and 0.1 to 0.12 portion of potassium sorbate.

The bacillus fermentation liquid is one or more of bacillus subtilis fermentation liquid, bacillus licheniformis fermentation liquid and bacillus amyloliquefaciens fermentation liquid. The number of viable bacteria in the biocontrol microbial inoculum is 2 multiplied by 10 ⁹ -5×10 ¹⁰ CFU/ml, the number of viable bacteria of the biological control agent in the liquid fertilizer is more than or equal to 1 multiplied by 10 ⁹ CFU/ml。

Yeast fermentation liquorThe lactobacillus fermentation liquor is acidophilic lactobacillus fermentation liquor. The number of viable bacteria in the buffer material is 1 × 10 ⁸ -1×10 ¹¹ CFU/ml, the number of viable bacteria of the buffer substance in the liquid fertilizer is more than or equal to 1 multiplied by 10 ⁹ CFU/ml。

The organic matter comprises 4-5 parts of mineral source potassium fulvate, 4-5 parts of molasses liquid and 4.5-6.5 parts of corn steep liquor. The mineral potassium fulvate comprises humic acid and fulvic acid, wherein the content of the humic acid is more than or equal to 30g/L, and the content of the fulvic acid is more than or equal to 20g/L.

The inorganic salt is one or more of urea, urea ammonium nitrate solution, potassium dihydrogen phosphate, ammonium polyphosphate, monoammonium phosphate, diammonium phosphate, potassium chloride, potassium sulfate and potassium nitrate.

The stabilizer is one or more of sodium dodecyl sulfate, methyl amyl alcohol, cellulose derivatives, carboxymethyl cellulose and vitamin C.

The preparation method of the liquid compound microbial fertilizer with long shelf life and no barrel expansion comprises the following steps:

(1) Mixing 40-50 parts of bacillus fermentation liquor, 15-20 parts of yeast fermentation liquor, 15-20 parts of lactobacillus fermentation liquor, 4-5 parts of molasses liquid, 4.5-6.5 parts of corn steep liquor, 0.05-0.08 part of sodium benzoate and 0.1-0.12 part of potassium sorbate, and stirring for 5-10min to obtain solution A;

(2) Adding 3-5 parts of inorganic salt into the solution A, and stirring for 10-15min to obtain solution B;

(3) Adding 4-5 parts of mineral source fulvic acid potassium into the solution B, and stirring for 5-10min to obtain solution C;

(4) And adding 0.3-0.5 part of stabilizer into the solution C, and stirring for 15-25min to obtain the liquid composite microbial fertilizer.

In order to make the technical solutions of the present application more clearly understood by those skilled in the art, the technical solutions of the present application will be described in detail below with reference to specific embodiments.

The test materials used in the examples of the present invention are all conventional in the art and commercially available.

Bacillus subtilis (Bacillus subtilis) used in the following examples and comparative examples was purchased from China agricultural microbial cultures Collection center with the collection number ACCC 60429; the Bacillus amyloliquefaciens (Bacillus amyloliquefaciens) is purchased from China agricultural microorganism strain preservation management center with the preservation number of ACCC 19746; the Saccharomyces cerevisiae (Saccharomyces cerevisiae) is purchased from China agricultural microbial strain preservation management center, and the preservation number is ACCC 21177; the Lactobacillus acidophilus (Lactobacillus acidophilus) is purchased from China agricultural microorganism culture collection center with the collection number of ACCC 10637.

Example 1

Mixing Bacillus fermentation liquid, lactobacillus acidophilus, saccharomyces cerevisiae mixed solution, molasses solution, sodium benzoate, and potassium sorbate, and stirring for 5min to obtain solution A; and adding monoammonium phosphate into the solution A, stirring for 10min to obtain solution B, adding 0.4 part of stabilizer into the solution B, and stirring for 20min to obtain the liquid composite microbial fertilizer. The raw materials are prepared into liquid composite microbial fertilizer according to the proportion shown in the table 1, the liquid composite microbial fertilizer is introduced into a barrel, a cover is pressed, a breathable film on the cover is kept smooth, the barrel is placed in a room at 30 ℃, the bacteria count detection is carried out periodically, and meanwhile, the bacteria film growth condition on the liquid surface is observed.

Table 1 formulation and grouping of example 1

Material(s)	A	B	C	D	E
						Bacillus subtilis fermentation liquor	40 portions of	40 portions of	40 portions of	100 portions of	100 portions of
Bacillus amyloliquefaciens fermentation liquor	10 portions of	10 portions of	10 portions of	0 portion of	0 portion of
						The volume ratio of lactobacillus acidophilus to saccharomyces cerevisiae =1:1	40 portions of	34.85 portions	30 portions of	0 portion of	0 portion of
Honey liquid	0 portion of	10 portions of	15 portions of	0 portion of	0 portion of
						Monoammonium phosphate	5 portions of	5 portions of	5 portions of	5 portions of	0 portion of
Sodium benzoate	0.05 part	0.05 part	0.05 part	0.05 part	0 portion of
						Potassium sorbate	0.10 part of	0.10 part of	0.10 portion	0.10 portion	0 portion of
Sodium dodecyl sulfate	0.4 portion of	0.4 portion of	0.4 portion of	0.4 portion of	0 portion of

1. Change in the number of bacteria

A. B, C, D, E the five groups showed relatively stable change in bacterial count, while the A, B, C group added with buffer and preservative showed a tendency of rapid decrease before stabilization in groups D and E without buffer or preservative.

The number of A group bacteria is reduced from 139 hundred million/ml to 96 hundred million/ml, and the death rate of the bacteria is 30.94%; the number of B group bacteria is reduced from 155 hundred million/ml to 112 hundred million/ml, and the bacterial death rate is 27.74 percent; the number of the group C bacteria is reduced from 171 hundred million/ml to 117 hundred million/ml, and the death rate of the bacteria is 31.58 percent; the number of the D group bacteria is reduced from 339 hundred million/ml to 221 hundred million/ml, and the death rate of the bacteria is 34.81 percent; the number of the E-treated bacteria is reduced from 337 hundred million/ml to 134 hundred million/ml, and the bacterial cell death rate is 60.24%.

Among them, the cell death rate was the lowest in group B, and the change in the number of cells was the most stable in group B in FIG. 1.

2. Change in appearance

A. 5363 the growth of the bacterial membrane on five groups of B, C, D, E is shown in fig. 3, the sterile membrane on the surface of A, B, C three groups is generated, and the difference between the inside and the outside is avoided; a thin bacterial film is arranged on the surface of the group D, and aerobic bacteria grow; a large amount of lawn is generated on the surface of the group E, and aerobic bacteria grow in a large amount.

About 1 week of storage, A, B, C, D, E five groups of overflow situations are shown in fig. 4, the D and E groups have overflow phenomena, the D group has the most serious overflow phenomenon, and other groups have no abnormality. The monoammonium phosphate added in the group D changes the whole environment of the liquid fertilizer into acidity, and the number of surviving bacilli is large and the bacilli are active, so that gas production is large and liquid overflowing is the most serious; the pH value of the group E after fermentation enables the bacillus to form a dormant body, the survival quantity of the bacillus is small, the gas production rate is not as high as that of the group D, and the liquid overflowing phenomenon is not as serious as that of the group D.

3. Change in odor

A. B, C, D, E five groups had odors after 60 days of storage as shown in table 2.

TABLE 2 odor of five groups A, B, C, D, E after 60 days storage

Treatment of	A	B	C	D	E
						Smell(s)	Taste of fermentation broth	Apple vinegar taste	Apple vinegar taste	Slightly off-flavor	Foul smell

The group A was not added with molasses, and the group B, C was added with molasses, so group A had a fermented liquid flavor, and group B, C had an apple vinegar flavor; in group E, only the Bacillus broth was added, and no buffer substance or preservative was added, thus showing malodor. Group D had a slight odor due to the addition of preservatives but no buffering substances.

4. Flatulence test

The samples of each group were stored at 60 ℃ for 24 hours, the volume change of the fertilizer was expressed as the air inflation, the pressure difference Δ P between the air inflation and the pre-air inflation of the liquid fertilizer closed system was measured using a U-tube pressure difference valve as shown in fig. 5, and the experimental results are shown in table 3.

TABLE 3 Pre-and post-inflation differential pressures for the five groups 3A, B, C, D, E

Treatment of	A	B	C	D	E
						△P/kpa	7	1.2	5	10	12

The inflation pressure difference of the group B is the minimum, and the smaller the pressure difference is, the smaller the inflation volume is, and the lower the inflation degree is. The pressure difference was greatest between group D and group E without the addition of buffer or preservative, and the degree of flatulence was highest.

In conclusion, the liquid fertilizer in group B has long preservation time, the minimum flatulence degree, stable change of the bacterial count, low bacterial mortality and the best effect.

Example 2

Mixing Bacillus subtilis fermentation broth, bacillus amyloliquefaciens fermentation broth, lactobacillus acidophilus, saccharomyces cerevisiae mixed solution, mel solution, sodium benzoate, and potassium sorbate, and stirring for 5min to obtain solution A; and adding monoammonium phosphate into the solution A, stirring for 10min to obtain solution B, adding 0.4 part of stabilizer into the solution B, and stirring for 20min to obtain the liquid composite microbial fertilizer. Liquid compound microbial fertilizer is prepared according to the proportion shown in table 4, added into a barrel, placed in a workshop, subjected to a storage test at room temperature, and periodically detected for bacterial count change.

TABLE 4 formulation of example 2

Material(s)	Mass portion of
		Bacillus subtilis fermentation liquor	40 portions of
Bacillus amyloliquefaciens fermentation liquid	10 portions of
		The volume ratio of lactobacillus acidophilus to saccharomyces cerevisiae =1:1	34.85 portions
Honey liquid	10 portions of
		Monoammonium phosphate	5 portions of
Sodium benzoate	0.05 part
		Potassium sorbate	0.10 portion
Sodium dodecyl sulfate	0.4 portion of

Comparative example 1

Mixing Bacillus subtilis fermentation liquid, bacillus amyloliquefaciens fermentation liquid, molasses liquid, sodium benzoate and potassium sorbate, and stirring for 5min to obtain solution A; and adding monoammonium phosphate into the solution A, stirring for 10min to obtain solution B, adding 0.4 part of stabilizer into the solution B, and stirring for 20min to obtain the liquid composite microbial fertilizer. The liquid compound microbial fertilizer is prepared according to the proportion shown in the table 5, added into a barrel, placed in a workshop, subjected to a storage test at room temperature, and periodically tested for the number of bacteria.

TABLE 5 formulation ratio of comparative example 1

Material(s)	Mass portion of
		Bacillus subtilis fermentation liquor	40 portions of
Bacillus amyloliquefaciens fermentation liquor	10 portions of
		The volume ratio of lactobacillus acidophilus to saccharomyces cerevisiae =1:1	0 portion of
Honey liquid	10 portions of
		Monoammonium phosphate	5 portions of
Sodium benzoate	0.05 part
		Potassium sorbate	0.10 part of
Sodium dodecyl sulfate	0.4 portion of

Comparative example 1 compared to example 2, no mixture of Lactobacillus acidophilus and Saccharomyces cerevisiae was added as a buffer.

Comparative example 2

Mixing Bacillus subtilis fermentation liquid, bacillus amyloliquefaciens fermentation liquid, acidophilic lactobacillus, saccharomyces cerevisiae mixed liquid, and molasses liquid, and stirring for 5min to obtain solution A; and adding monoammonium phosphate into the solution A, stirring for 10min to obtain solution B, adding 0.4 part of stabilizer into the solution B, and stirring for 20min to obtain the liquid composite microbial fertilizer. Liquid compound microbial fertilizer is prepared according to the proportion shown in table 6, added into a barrel, placed in a workshop, subjected to a storage test at room temperature, and periodically tested for the number of bacteria.

TABLE 6 formulation of comparative example 2

Material(s)	Mass portion of
		Bacillus subtilis fermentation liquor	40 portions of
Bacillus amyloliquefaciens fermentation liquor	10 portions of
		The volume ratio of lactobacillus acidophilus to saccharomyces cerevisiae =1:1	34.85 portions of
Honey liquid	10 portions of
		Monoammonium phosphate	5 portions of
Sodium benzoate	0 portion of
		Potassium sorbate	0 portion of
Sodium dodecyl sulfate	0.4 part of

Comparative example 2 compared to example 2 no sodium benzoate and potassium sorbate were added as preservatives.

Comparative example 3

Mixing Bacillus subtilis fermentation liquid, bacillus amyloliquefaciens fermentation liquid and molasses liquid, and stirring for 5min to obtain solution A; and adding monoammonium phosphate into the solution A, stirring for 10min to obtain solution B, adding 0.4 part of stabilizer into the solution B, and stirring for 20min to obtain the liquid composite microbial fertilizer. Liquid compound microbial fertilizer is prepared according to the proportion shown in table 7, added into a barrel, placed in a workshop, subjected to a storage test at room temperature, and periodically tested for the number of bacteria.

TABLE 7 formulation ratio of comparative example 2

Material(s)	Mass portion of
		Bacillus subtilis fermentation liquor	40 portions of
Bacillus amyloliquefaciens fermentation liquor	10 portions of
		The volume ratio of lactobacillus acidophilus to saccharomyces cerevisiae =1:1	0 portion of
Honey liquid	10 portions of
		Monoammonium phosphate	5 portions of
Sodium benzoate	0 portion of
		Potassium sorbate	0 portion of
Sodium dodecyl sulfate	0.4 portion of

Comparative example 3 compared to example 2 no buffer substance and no preservative were added.

The change in the number of bacteria in example 2 and comparative examples 1 to 2 is shown in FIG. 2.

Each group of samples was stored at 60 ℃ for 24 hours, the volume change of the fertilizer was expressed as the air inflation condition, the pressure difference Δ P between the liquid fertilizer closed system after air inflation and before air inflation was measured by using a U-tube pressure difference valve as shown in FIG. 5, and the experimental results are shown in Table 8.

TABLE 8 pressure difference DeltaP after and before inflation for example 2 and comparative examples 1 to 3

The smaller the pressure difference, the smaller the inflation volume and the lower the degree of inflation.

Example 2 was reduced by 9.7kpa relative to the pressure difference of comparative example 3 as a blank, comparative example 1 with no preservative added to the buffer substance was reduced by 5.7kpa relative to the pressure difference of comparative example 3, and comparative example 2 with no preservative added to the buffer substance was reduced by 1.5kpa relative to the pressure difference of comparative example 3; the buffer substance and the preservative used in the invention have a synergistic effect on solving the problem of barrel expansion.

As can be seen from Table 8, the pressure difference of the comparative example 2 is larger than that of the comparative example 1, and the flatulence volume is larger, because the preservative added in the comparative example 1 can inhibit the growth and the propagation of strains, only the bacillus in the liquid fertilizer in the comparative example 1 is in a inhibited state, and the strains do not actively produce gas, the buffer substance added in the comparative example 2 can adjust the pH value to enable the bacillus to be in a dormant state, but the yeast and the lactic acid bacteria still actively produce more gas, so the flatulence volume of the comparative example 2 is larger than that of the comparative example 1; in the embodiment 2, the preservative and the buffer substance are added, the pH value of the buffer substance is adjusted to enable the bacillus to be in a dormant state, the preservative inhibits the activity of saccharomycetes and lactic acid bacteria, and the preservative and the lactic acid bacteria are cooperated to reduce the gas production rate of the liquid fertilizer without barrel expansion.

As can be seen from FIG. 2, the number of bacteria in example 2 is slightly reduced with the increase of the storage time, and when the storage time is up to 90 days, the bacteria gradually balance and are maintained between 135 hundred million/ml and 142 hundred million/ml, so that the bacteria meet the design requirement of the product, and the shelf life is higher than the specification of more than or equal to 3 months of the Ministry of agriculture (NY/T798-2015). The number of bacteria in the comparative example 1 and the comparative example 2 is changed violently, the final number of bacteria in the comparative example 1 is maintained between 40 and 50 hundred million/ml, and the final number of bacteria in the comparative example 2 is maintained between 80 and 90 hundred million/ml.

The problem that the liquid fertilizer expands the barrel is solved by utilizing the synergistic effect of the buffer substance and the preservative, the preservative plays a role in inhibiting the growth and the propagation of strains in the liquid fertilizer, so that the strains are in an inhibition state, the activity of the strains is low, and gas is not generated any more; the invention utilizes the buffer substances, namely lactic acid and lactate, generated in the yeast fermentation liquor and the lactic acid bacteria fermentation liquor to form a buffer pair, and the buffer pair can be adjusted to be acid when meeting acid and alkali when meeting alkali, so as to play the roles of adjusting the change of pH value and stabilizing the liquid environment, so that the strain is in a dormant state, the strain activity is low, the amount of generated gas is small, and the barrel does not expand. The preservative and the buffering substance used in the invention have a synergistic effect on solving the problem of barrel swelling of liquid fertilizer.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. The liquid compound microbial fertilizer with long shelf life and no barrel expansion is characterized by comprising the following components in parts by mass:

40-50 parts of biocontrol microbial inoculum, 30-40 parts of buffer substance, 12.5-16.5 parts of organic substance, 0.15-0.2 part of preservative, 3-5 parts of inorganic salt and 0.3-0.5 part of stabilizer;

the biocontrol microbial inoculum is bacillus fermentation liquor; the buffer substance comprises 15 to 20 parts of yeast fermentation liquor and 15 to 20 parts of lactobacillus fermentation liquor; the preservative comprises 0.05 to 0.08 portion of sodium benzoate and 0.1 to 0.12 portion of potassium sorbate.

2. The liquid composite microbial fertilizer according to claim 1, wherein the bacillus fermentation broth is one or more of bacillus subtilis fermentation broth, bacillus licheniformis fermentation broth and bacillus amyloliquefaciens fermentation broth.

3. The liquid compound microbial fertilizer as claimed in claim 1, wherein the number of viable bacteria in the biocontrol microbial agent is 2 x 10 ⁹ -5×10 ¹⁰ CFU/ml。

4. The liquid composite microbial fertilizer according to claim 1, wherein the yeast fermentation broth is a saccharomyces cerevisiae fermentation broth, and the lactic acid bacteria fermentation broth is an acidophilic lactic acid bacteria fermentation broth.

5. The liquid composite microbial fertilizer according to claim 1, wherein the number of viable bacteria in the buffer substance is 1 x 10 ⁸ -1×10 ¹¹ CFU/ml。

6. The liquid composite microbial fertilizer according to claim 1, wherein the organic matter comprises 4-5 parts of mineral potassium fulvate, 4-5 parts of molasses liquid and 4.5-6.5 parts of corn steep liquor.

7. The liquid composite microbial fertilizer according to claim 6, wherein the components of the mineral potassium fulvate comprise humic acid and fulvic acid, the humic acid content is not less than 30g/L, and the fulvic acid content is not less than 20g/L.

8. The liquid composite microbial fertilizer according to claim 1, wherein the inorganic salt is one or more of urea, urea ammonium nitrate solution, monopotassium phosphate, ammonium polyphosphate, monoammonium phosphate, diammonium phosphate, potassium chloride, potassium sulfate and potassium nitrate.

9. The liquid composite microbial fertilizer according to claim 1, wherein the stabilizer is one or more of sodium dodecyl sulfate, methylpentanol, cellulose derivatives, carboxymethyl cellulose, vitamin C.

10. The method for preparing the liquid compound microbial fertilizer with long shelf life and no barrel expansion as claimed in any one of claims 1 to 9, is characterized by comprising the following steps:

(1) Mixing 40-50 parts of bacillus fermentation liquor, 15-20 parts of yeast fermentation liquor, 15-20 parts of lactobacillus fermentation liquor, 4-5 parts of molasses liquid, 4.5-6.5 parts of corn steep liquor, 0.05-0.08 part of sodium benzoate and 0.1-0.12 part of potassium sorbate, and stirring for 5-10min to obtain solution A;

(2) Adding 3-5 parts of inorganic salt into the solution A, and stirring for 10-15min to obtain solution B;

(3) Adding 4-5 parts of mineral source fulvic acid potassium into the solution B, and stirring for 5-10min to obtain solution C;

(4) And adding 0.3-0.5 part of stabilizer into the solution C, and stirring for 15-25min to obtain the liquid composite microbial fertilizer.

Images