Compound microbial soil conditioner and preparation method thereof

Abstract

The invention relates to the technical field of soil amendment preparation, in particular to a compound microorganism soil amendment and a preparation method thereof.The preparation method comprises the steps that the initial molecular weight of an embedding layer of a single strain is determined based on the single growth cycle of crops, and a target strain is embedded to obtain a plurality of embedded strains; determining the latent duration of the target strain to determine whether the initial molecular weight is qualified, and adjusting the initial molecular weight according to the degradation rate of the embedding layer to obtain the implementation molecular weight; determining the embedding sequence of a plurality of strains based on the growth cycle of crops, and embedding a plurality of target strains to prepare compound microorganisms; determining whether the release process of the compound microorganisms is qualified or not according to the overlapping degree so as to optimize the implementation molecular weight based on the change condition of the degradation environment; and mixing the optimized compound microorganism with other components in proportion to obtain the compound microorganism soil conditioner. The purpose of accurately matching the soil conditioner with the whole growth period requirements of crops is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil conditioner preparation, and in particular to a composite microbial soil conditioner and a preparation method thereof. Background Art

[0002] Most existing soil conditioners use a single or simple composite encapsulation material to slowly release microbial strains, but the existing technology has significant defects in the design of the slow-release rate - the slow-release parameters are not set specifically according to the soil type, crop needs and microbial functional characteristics. For example, saline-alkali soil has a high pH and high ionic strength, so the strain release period needs to be extended to avoid the high pH environment inhibiting the activity of functional bacteria; while acidic soil or facility agriculture environment needs to shorten the slow-release time to prevent the strain from being inactivated due to long-term retention. However, the degradation rate of the encapsulation material in the existing technology is mostly a fixed parameter, resulting in the release of the strain being either too fast or too slow, ultimately resulting in a short-lasting improvement effect, nutrient loss or waste of resources. In addition, the existing slow-release design does not distinguish between differences in microbial functions, and the degradation rate of the unified encapsulation material cannot match the full growth period requirements of "early microenvironment improvement-mid-term disease resistance and root promotion-late nutrient supply", which limits the actual application effect of the soil conditioner.

[0003] Chinese Patent Application Publication No. CN119841686A discloses a microbial composite soil conditioner and its preparation method. The various microorganisms in the microbial composite soil conditioner can promote the decomposition of organic matter in the soil, increasing the soil's air permeability and water retention. At the same time, zeolite powder and rice husk ash components can improve the soil's pore structure, enhance its drainage capacity and aeration, thereby optimizing the growth environment for crop roots. Decomposed organic fertilizer and edible fungus residue are rich in nitrogen, phosphorus, and potassium nutrients, providing a continuous and stable nutrient supply for crops. Furthermore, the amino acid stock solution, wood vinegar, and molasses liquid components contain a variety of trace elements and bioactive substances, which help enhance the disease resistance and growth vitality of crops. Due to the improved soil structure, increased fertility, and enhanced microbial activity, crops can better absorb nutrients and water, reducing the occurrence of pests and diseases, and effectively increasing crop yields and quality.

[0004] The following problems also exist in the existing technology: the existing technology does not set the ratio of the embedding material in the sustained-release process of the soil conditioner according to the soil type, crop needs and microbial functional characteristics, and cannot ensure the timely release of various strains in the soil conditioner, resulting in the soil conditioner being unable to accurately match the full growth period needs of the crop, resulting in low actual application efficiency of the soil conditioner. Summary of the Invention

[0005] To this end, the present invention provides a composite microbial soil conditioner and a preparation method thereof, which are used to overcome the problem in the prior art that the ratio of the embedding material is not set in a targeted manner according to the soil type, crop requirements and microbial functional characteristics, and the timely release of each bacterial species in the soil conditioner cannot be guaranteed, resulting in the soil conditioner being unable to accurately match the full growth period requirements of the crop.

[0006] To achieve the above objectives, the present invention provides a method for preparing a composite microbial soil conditioner, comprising:

[0007] Determining the release duration of a single bacterial species based on a single growth cycle of the crop to determine the initial molecular weight of the embedding layer of the single bacterial species, and embedding the target bacterial species according to the initial molecular weight to obtain a plurality of embedded bacterial species;

[0008] Placing the embedded bacteria in a preset degradation environment to determine the incubation time of the target bacteria to determine whether the initial molecular weight of the embedded layer is qualified, and adjusting the initial molecular weight according to the degradation rate of the embedded layer to obtain the implemented molecular weight;

[0009] Determining an embedding order of several bacterial species based on the growth cycle of the crop, and embedding several target bacterial species according to the embedding order to prepare a composite microorganism;

[0010] Placing the composite microorganism in a preset degradation environment to determine the overlap of release times of several bacterial species to determine whether the release process of the composite microorganism is qualified, and determining the release time of a single bacterial species if the release process of the composite microorganism is determined to be unqualified, so as to optimize the implementation molecular weight based on changes in the degradation environment during the release process of a previous layer of bacterial species adjacent to the bacterial species with unqualified release time;

[0011] The optimized composite microorganism is mixed with other ingredients in proportion to obtain a composite microbial soil conditioner, wherein the other ingredients include pyrocatechol, an ammonia stabilizer and polyglutamic acid.

[0012] Furthermore, the process of determining whether the initial molecular weight of the embedding layer is qualified according to the incubation time of the target bacterial strain includes:

[0013] Comparing the latency periods with preset latency periods respectively;

[0014] Determining that the initial molecular weight of the embedding layer is unqualified based on a comparison result that the incubation time is less than a first preset incubation time or greater than a second preset incubation time;

[0015] The second preset latency period is greater than the first preset latency period.

[0016] Furthermore, under the condition that the initial molecular weight is determined to be unqualified, the process of adjusting the initial molecular weight according to the degradation rate of the embedding layer includes:

[0017] comparing the degradation rates with preset rates respectively;

[0018] Based on the comparison result that the degradation rate is less than the first preset rate, subtracting the first preset rate from the degradation rate to obtain a first rate difference value, or based on the comparison result that the degradation rate is greater than the second preset rate, subtracting the degradation rate from the first preset rate to obtain a second rate difference value;

[0019] A plurality of molecular weight adjustment coefficients corresponding to the first rate difference and the second rate difference are provided to adjust the initial molecular weight according to the molecular weight adjustment coefficients.

[0020] Furthermore, the process of determining whether the release process of the composite microorganism is qualified according to the overlap of the release time of several target strains includes:

[0021] comparing the overlap degrees with preset overlap degrees respectively;

[0022] Determining that the release process of the composite microorganism is unqualified based on a comparison result that the overlap is less than a first preset overlap or greater than a second preset overlap;

[0023] The second preset overlap is greater than the first preset overlap.

[0024] Furthermore, under the condition that the release process of the composite microorganism is determined to be unqualified, the process of determining whether the release time of a single target bacterial species is qualified includes:

[0025] Comparing the release durations with preset release durations respectively;

[0026] Determining that the release time of the single target bacterial species is unqualified based on a comparison result that the release time is less than the first preset release time or the release time is greater than the second preset release time;

[0027] The second preset release time is greater than the first preset release time.

[0028] Furthermore, under the condition that the release time of a single target bacterial species is determined to be unqualified, the process of optimizing the molecular weight according to the pH change of the degradation environment during the release process of the target bacterial species in the previous layer adjacent to the target bacterial species includes:

[0029] comparing the pH change value with a preset change value;

[0030] Determining to optimize the implemented molecular weight based on a comparison result that the pH value change value is greater than or equal to a preset change value;

[0031] Subtracting the pH change value from the preset change value to obtain a change difference;

[0032] A number of molecular weight optimization coefficients corresponding to the variation differences are set to optimize the implemented molecular weight.

[0033] On the other hand, the present invention also provides a composite microbial soil conditioner prepared according to the composite microbial soil conditioner preparation method, comprising: 85-93 parts of composite microorganisms, 1-3 parts of pyrocatechol, 1-3 parts of ammonia stabilizer, and 2-6 parts of polyglutamic acid.

[0034] Furthermore, the composite microorganism includes 80 to 100 parts of a quick-release layer, 90 to 110 parts of a sustained-release layer and 100 to 120 parts of a long-acting layer, the quick-release layer includes 25 to 35 parts of green algae, 15 to 25 parts of yeast, 3 to 6 parts of sucrose, 8 to 10 parts of volcanic ash and 8 to 10 parts of humic acid, the sustained-release layer includes 30 to 40 parts of lactic acid bacteria, 10 to 12 parts of humic acid and 10 to 12 parts of volcanic ash, and the long-acting layer includes 35 to 50 parts of Bacillus subtilis, 30 to 40 parts of biochar and 15 to 30 parts of bentonite.

[0035] Furthermore, the composite microbial soil conditioner is a three-layer embedding material, the outer layer is a quick-release layer, the middle layer is a slow-release layer, and the inner layer is a long-acting layer.

[0036] Furthermore, the embedding material of the quick-release layer is sodium alginate gel, the embedding material of the sustained-release layer is chitosan, and the embedding material of the long-acting layer is polylactic acid-glycolic acid copolymer.

[0037] Compared with the prior art, the beneficial effect of the present invention is that the present invention determines the release time of a single bacterial species through a single growth cycle of the crop. Different growth cycles of crops have different requirements for bacterial species. For example, the core requirements of crops in the seedling stage for the soil are to ensure oxygen supply, decomposition of organic matter and release of basic nutrients to improve the germination rate. Green algae, as an aerobic microorganism, can release oxygen through photosynthesis and directly improve the oxygen-deficient environment in the rhizosphere. Yeast can decompose organic matter such as cellulose and starch remaining in the soil and produce fast-acting nutrients such as amino acids and small molecule sugars to meet the urgent needs of seedlings for carbon and nitrogen. Sucrose, as a fast-acting carbon source, can activate the short-term activity of original soil microorganisms (such as Bacillus amyloliquefaciens) and cooperate with yeast to accelerate the decomposition of organic matter. At the same time, the organic matter produced by sucrose degradation Organic acids (such as citric acid) can lower the local pH value and promote the photosynthesis of green algae. Sodium alginate as the embedding layer of the quick-release layer can ensure the rapid release of green algae and lactic acid bacteria within 7 to 10 days, so as to ensure that the components of the quick-release layer are quickly released and play their role in the seedling stage, avoiding germination disorders caused by hypoxia; after the seedling stage, crops enter the growth period. At this stage, crops enter the period of vigorous nutritional growth, and the root system expands rapidly. They face the dual challenges of soil-borne pathogen infection and autotoxicity caused by accumulation of root secretions. The core demand is biological control and root microecological balance. Lactic acid bacteria, as Gram-positive bacteria, can directly inhibit the reproduction of pathogens by producing lactic acid and secreting bacteriocins (such as Nisin). At the same time, the organic acids produced by their metabolism can complex heavy metal ions in the soil (such as Pb 2 +、Cd 2 +), reducing the toxicity to the root system, chitosan as the embedding layer of the slow-release layer can ensure degradation in 20 to 30 days, so that lactic acid bacteria begin to be released in the late seedling stage (2 to 4 weeks), and continue to act until the middle of the growth period (6 to 8 weeks), which is highly synchronized with the timeline of the "latent-outbreak" of pathogens; after the growth period, crops enter the flowering and fruiting period, and the demand for mineral nutrients such as phosphorus and potassium surges (accounting for more than 60% of the entire growth period). At the same time, they face challenges such as soil nutrient depletion and drought / salt stress. The core demand is long-term nutrient supply and enhanced stress resistance. Bacillus subtilis, as a phosphate and potassium-solubilizing bacterium, can secrete organic acids (such as oxalic acid and gluconic acid) to dissolve the insoluble phosphorus and potassium in the soil and convert them into absorbable At the same time, the antibacterial substances it produces can inhibit the secondary infection of later pathogens (such as Botrytis cinerea). The porous structure of biochar can adsorb organic acids secreted by Bacillus subtilis, phosphate and potassium solubilization products, and ammonium nitrogen and available phosphorus in the soil, avoiding nutrient loss due to leaching (the leaching rate of traditional fertilizers is >30%, and biochar can reduce it to less than 10%). The weak alkalinity of biochar can neutralize soil acidification and provide a more suitable living environment for Bacillus subtilis. The synergistic effect of polylactic acid-glycolic acid copolymer and biochar can extend the nutrient supply cycle to more than 120 days, covering the entire flowering and fruiting period, thereby accurately matching the full growth period needs of crops and improving the actual application efficiency of soil conditioners.

[0038] Furthermore, the present invention adjusts the initial molecular weight of each embedding layer based on the release time of a single bacterial strain. The degradation time of sodium alginate is positively correlated with the molecular weight of sodium alginate and the cross-linking strength with divalent cations. An acidic environmental pH value inhibits the activity of alginate lyase and delays degradation, while a neutral / weakly alkaline environment accelerates enzymatic hydrolysis. The degradation time of chitosan is positively correlated with the degree of deacetylation and molecular weight. An acidic environmental pH value accelerates degradation, while a neutral / weakly alkaline environment slows down degradation. The degradation rate of polylactic acid-glycolic acid copolymer is determined by the copolymerization ratio of lactic acid to glycolic acid and the molecular weight. The higher the glycolic acid content, the faster the degradation rate, and the lower the molecular weight, the faster the degradation rate. The ratio of the embedding layer is adjusted and optimized in a targeted manner according to the degradation characteristics of each embedding layer and the crop growth cycle, thereby accurately matching the full growth period requirements of the crop and improving the actual application efficiency of the soil conditioner.

[0039] Furthermore, in the present invention, the release order of each layer of embedded bacteria is not that the next layer starts to release after the previous layer is completely released, but rather a partially overlapping release, that is, when the bacteria in the previous layer have not yet been completely released, the bacteria in the next layer have begun to be gradually released, so as to avoid the functional window period and ensure the continuous coverage of the functions of bacteria in different growth stages. At the same time, through the gradient control of the material degradation rate, the precise connection of "early-middle-late" is achieved, so as to further optimize the material ratio of each embedded layer according to the overlapping time, so that the soil conditioner can accurately match the full growth period needs of the crop, thereby improving the actual application efficiency of the soil conditioner.

[0040] Furthermore, the present invention further optimizes the material ratio of the embedding layer through the objective impact of each embedding layer on the soil environment. During the implementation of the soil conditioner, various microscopic effects will cause the soil environment to show different changes. The macroscopic manifestations are mostly different pH values ​​or environmental humidity. Environmental changes will have an unavoidable impact on the degradation rate of each embedding layer. Therefore, according to the changes in the soil environment, the material ratio of each embedding layer is precisely optimized to make the soil conditioner accurately match the full growth period requirements of the crop, thereby improving the actual application efficiency of the soil conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a method for preparing a composite microbial soil conditioner according to an embodiment of the present invention;

[0042] Figure 2 A flow chart showing whether the initial molecular weight of the embedding layer is qualified according to an embodiment of the present invention;

[0043] Figure 3 A flow chart for determining whether a composite microbial release process is qualified according to an embodiment of the present invention;

[0044] Figure 4 This is a schematic structural diagram of a composite microbial soil conditioner according to an embodiment of the present invention;

[0045] In the figure: 1. Immediate-release layer, 2. Sustained-release layer, 3. Long-acting layer. DETAILED DESCRIPTION

[0046] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0047] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0048] See also Figure 1 As shown, Figure 1 This is a flow chart of a method for preparing a composite microbial soil conditioner according to an embodiment of the present invention; Figure 2 A flow chart showing whether the initial molecular weight of the embedding layer is qualified according to an embodiment of the present invention; Figure 3 This is a flow chart for determining whether the release process of composite microorganisms is qualified according to an embodiment of the present invention.

[0049] The present invention provides a method for preparing a composite microbial soil conditioner, comprising:

[0050] Step S1, determining the release time of a single bacterial strain based on a single growth cycle of the crop to determine the initial molecular weight of the embedding layer of the single bacterial strain, and embedding the target bacterial strain according to the initial molecular weight to obtain a plurality of embedded bacterial strains;

[0051] Step S2, placing the embedded bacteria in a preset degradation environment to determine the incubation time of the target bacteria to determine whether the initial molecular weight of the embedded layer is qualified, and adjusting the initial molecular weight according to the degradation rate of the embedded layer to obtain the implemented molecular weight;

[0052] Step S3, determining an embedding order of the plurality of bacterial strains based on the growth cycle of the crop, and embedding the plurality of target bacterial strains according to the embedding order to prepare a composite microorganism;

[0053] Step S4, placing the composite microorganism in a preset degradation environment to determine the overlap of release times of several strains to determine whether the release process of the composite microorganism is qualified, and determining the release time of a single strain if the release process of the composite microorganism is determined to be unqualified, so as to optimize the implementation molecular weight based on the changes in the degradation environment during the release process of the previous layer of strains adjacent to the strain with unqualified release time;

[0054] Step S5, mixing the optimized composite microorganism with other ingredients in proportion to obtain a composite microbial soil conditioner, wherein the other ingredients include pyrocatechol, an ammonia stabilizer, and polyglutamic acid.

[0055] It is understandable that the growth cycles of different growth stages of a single crop are different. For example, the seedling stage (sowing and emergence stage) of cotton is the 7th to 15th day, the growth period (seedling stage + bud stage) is the 75th to 100th day, and the flowering and fruiting period (flowering and boll stage + boll opening stage) is the 120th to 150th day. According to the requirements of the crop growth stage, the release time of a single strain is set, such as 7 to 15 days for the quick-release layer, 75 to 100 days for the slow-release layer, and 120 to 150 days for the long-acting layer. The release time determines the degradation rate of the embedding layer, and the degradation rate is related to the molecular weight of the embedding layer material. Therefore, the release time of a single strain can be determined according to the single growth cycle of the crop to determine the initial molecular weight of the embedding layer of a single strain.

[0056] Specifically, the initial molecular weight of the embedding layer of a single bacterial species is determined according to the growth cycle of the crop to prepare the corresponding embedding material. Taking the degradation cycle of the 7th to 15th day as an example, the initial molecular weight of the sodium alginate embedding material is 80kDa; taking the degradation cycle of the 75th to 100th day as an example, the initial molecular weight of the chitosan embedding material is 100kDa; taking the degradation cycle of the 120th to 150th day as an example, the initial molecular weight of the polylactic acid-glycolic acid copolymer (PLA) embedding material is 150kDa.

[0057] It is understandable that before embedding the bacterial strains, the bacterial strains need to be activated and the activity of the activated bacterial strains needs to be tested. This is a prior art and will not be described in detail.

[0058] Specifically, the preset degradation environment is a natural degradation environment simulated according to specific crops. Different crops have different degradation environments.

[0059] Specifically, the process of determining whether the initial molecular weight of the embedding layer is qualified based on the incubation time of the target bacterial species includes:

[0060] Comparing the latency periods with preset latency periods respectively;

[0061] Determining that the initial molecular weight of the embedding layer is unqualified based on a comparison result that the incubation time is less than a first preset incubation time or greater than a second preset incubation time;

[0062] Determining that the initial molecular weight of the embedding layer is qualified based on a comparison result that the incubation period is greater than or equal to the first preset incubation period and less than or equal to the second preset incubation period;

[0063] The second preset latency period is greater than the first preset latency period.

[0064] Specifically, the incubation period refers to the time difference from the completion of embedding to the beginning of material degradation and the first contact of the bacteria with the external environment. The preset incubation period is determined according to different embedding layers. For example, for the quick-release layer, the value range of the first preset incubation period is set to [3 days, 5 days], and the embodiment of the present invention is preferably 4 days; the value range of the second preset incubation period is set to [7 days, 10 days], and the embodiment of the present invention is preferably 8 days; for the sustained-release layer, the value range of the first preset incubation period is set to [20 days, 40 days], and the embodiment of the present invention is preferably 30 days; the value range of the second preset incubation period is set to [50 days, 70 days], and the embodiment of the present invention is preferably 60 days; for the long-acting layer, the value range of the first preset incubation period is set to [70 days, 90 days], and the embodiment of the present invention is preferably 80 days; the value range of the second preset incubation period is set to [100 days, 150 days], and the embodiment of the present invention is preferably 100 days.

[0065] Specifically, under the condition that the initial molecular weight is determined to be unqualified, the process of adjusting the initial molecular weight according to the degradation rate of the embedding layer includes:

[0066] comparing the degradation rates with preset rates respectively;

[0067] Based on the comparison result that the degradation rate is less than the first preset rate, subtracting the first preset rate from the degradation rate to obtain a first rate difference value, or based on the comparison result that the degradation rate is greater than the second preset rate, subtracting the degradation rate from the first preset rate to obtain a second rate difference value;

[0068] A plurality of molecular weight adjustment coefficients corresponding to the first rate difference and the second rate difference are provided to adjust the initial molecular weight according to the molecular weight adjustment coefficients.

[0069] Specifically, the degradation rate is calculated as follows: degradation rate = (initial mass - residual mass) / ratio of initial mass / time.

[0070] Specifically, the value of the preset rate is determined according to the actual degradation process, and the value is different for different embedding layers. For the quick-release layer, the value range of the first preset rate is set to [0.1g / d, 0.3g / d], and the embodiment of the present invention is preferably 0.2g / d. The value range of the second preset rate is set to [0.4g / d, 0.6g / d], and the embodiment of the present invention is preferably 0.5g / d; for the sustained-release layer, the value range of the first preset rate is set to [0.05g / d, 0.12g / d d], the embodiment of the present invention is preferably 0.1g / d, the value range of the second preset rate is set to [0.13g / d, 0.2g / d], and the embodiment of the present invention is preferably 0.15g / d; for the long-acting layer, the value range of the first preset rate is set to [0.03g / d, 0.06g / d], and the embodiment of the present invention is preferably 0.05g / d, the value range of the second preset rate is set to [0.07g / d, 0.09g / d], and the embodiment of the present invention is preferably 0.08g / d.

[0071] Specifically, comparing the first rate difference or the second rate difference with a preset difference;

[0072] Determining to reduce the initial molecular weight by a first molecular weight adjustment coefficient based on a comparison result that the first rate difference is greater than or equal to the preset difference;

[0073] Determining to reduce the initial molecular weight by a second molecular weight adjustment coefficient based on a comparison result that the first rate difference is less than the preset difference;

[0074] determining to increase the initial molecular weight by a third molecular weight adjustment coefficient based on a comparison result that the second rate difference is greater than or equal to the preset difference;

[0075] Based on the comparison result that the second rate difference is less than the preset difference, it is determined to increase the initial molecular weight by a fourth molecular weight adjustment coefficient.

[0076] Specifically, the value of the preset difference is determined according to the experimental data of the degradation process, and the specific value range is set to [0.005 g / d, 0.015 g / d], and the embodiment of the present invention is preferably 0.01 g / d; the value range of the first molecular weight adjustment coefficient is set to [0.85, 0.9], and the embodiment of the present invention is preferably 0.85; the value range of the second molecular weight adjustment coefficient is set to [0.91, 0.96], and the embodiment of the present invention is preferably 0.95; the value range of the third molecular weight adjustment coefficient is set to [1.06, 1.12], and the embodiment of the present invention is preferably 1.1; the value range of the fourth molecular weight adjustment coefficient is set to [1.03, 1.05], and the embodiment of the present invention is preferably 1.04.

[0077] It can be understood that the degradation rate of each layer of embedding material is negatively correlated with the molecular weight.

[0078] Specifically, the process of determining whether the release process of the composite microorganism is qualified based on the overlap of the release time of several target strains includes:

[0079] comparing the overlap degrees with preset overlap degrees respectively;

[0080] Determining that the release process of the composite microorganism is unqualified based on a comparison result that the overlap is less than a first preset overlap or greater than a second preset overlap;

[0081] Determining that the release process of the composite microorganisms is qualified based on a comparison result that the overlap degree is greater than or equal to the first preset overlap degree and the overlap degree is less than or equal to the second preset overlap degree;

[0082] The second preset overlap is greater than the first preset overlap.

[0083] It can be understood that the overlap is the overlapping ratio of the release time of each target species in the composite microorganism. The demand for microbial functions in different growth stages of crops is time-sequential. For example, growth-promoting bacteria need to start quickly in the seedling stage, nitrogen-fixing bacteria need to continuously supply nitrogen in the growth period, and phosphate-solubilizing bacteria need to release nutrients in the mature period. If the release time of adjacent species has no overlap or insufficient overlap, that is, the overlap is less than the first preset overlap, it may cause the species in the previous stage to be exhausted prematurely, while the species in the next stage have not yet been released, forming a "functional vacuum". If the release time of adjacent species overlaps too much, the overlap is greater than the second preset overlap, which may cause multiple species to be "clustered" and released in the same stage. Different species may compete for the same nutrients, such as carbon sources, nitrogen sources or living space, resulting in the activity of some species decreasing due to insufficient resources. At the same time, some species may secrete metabolites that inhibit the activity of other species, such as antibiotics and organic acids. If the overlapping release time of two species is too long, they may inhibit each other and weaken the overall function.

[0084] Specifically, the value of the preset overlap is determined according to the growth requirements of specific crops. The value range of the first preset overlap is set to [10%, 40%], and 30% is preferred in the embodiment of the present invention. The value range of the second preset overlap is set to [50%, 60%], and 50% is preferred in the embodiment of the present invention. It can be understood that the setting of the overlap is essentially a quantitative regulation of the "release rhythm". The first preset overlap ensures that the "surplus" of the bacterial species in the previous stage can buffer the "start-up delay" of the bacterial species in the next stage, avoiding the risk of release lag due to environmental fluctuations, such as rainfall delays and soil temperature changes; the second preset overlap limits the "early entry" of the bacterial species in the next stage, avoiding premature consumption of resources or conflict with the functions of the bacterial species in the previous stage.

[0085] Specifically, under the condition that the release process of the composite microorganism is determined to be unqualified, the process of determining whether the release time of a single target bacterial species is qualified includes:

[0086] Comparing each of the release durations with a preset release duration;

[0087] Determining that the release time of the single target bacterial species is unqualified based on a comparison result that the release time is less than the first preset release time or the release time is greater than the second preset release time;

[0088] Determining that the release duration of a single target bacterial species is qualified based on a comparison result that the release duration is greater than or equal to the first preset release duration and the release duration is less than or equal to the second preset release duration;

[0089] The second preset release time is greater than the first preset release time.

[0090] Specifically, the preset release time is determined according to different encapsulation materials. For example, for the quick-release layer material sodium alginate, the value range of the first preset release time is set to [3d, 7d], and 5d is preferred in the embodiment of the present invention. The value range of the second preset release time is set to [18d, 22d], and 20d is preferred in the embodiment of the present invention. A release time shorter than the first preset release time may result in the material not fully protecting the bacterial strain and degrading, or the nutrients being exhausted prematurely. A release time longer than the second preset release time cannot meet the "quick response" requirement in the seedling stage.

[0091] For the sustained-release layer material chitosan, the value range of the first preset release time is set to [25d, 35d], and 30d is preferred in the embodiment of the present invention. The value range of the second preset release time is set to [55d, 65d], and 60d is preferred in the embodiment of the present invention. If the release time is less than the first preset time, the nutrients will be released too early and cannot cover the medium-term demand. If the release time is greater than the second preset release time, the release of the bacteria will be delayed and cannot respond to the growth period demand in time.

[0092] For the long-lasting layer material PLA, the value range of the first preset release time is set to [80d, 95d], and 90d is preferred in the embodiment of the present invention. The value range of the second preset release time is set to [100d, 110d], and 105d is preferred in the embodiment of the present invention. If the release time is less than the first preset time, the material will fail prematurely and cannot meet long-term needs. If the release time is greater than the second preset time, it means that the material degrades too slowly and may accumulate harmful substances.

[0093] Specifically, under the condition that the release time of a single target bacterial species is determined to be unqualified, the process of optimizing the molecular weight according to the pH change of the degradation environment during the release process of the target bacterial species in the previous layer adjacent to the target bacterial species includes:

[0094] comparing the pH change value with a preset change value;

[0095] Determining to optimize the implemented molecular weight based on a comparison result that the pH value change value is greater than or equal to a preset change value;

[0096] Determining not to optimize the implemented molecular weight based on a comparison result that the pH value change value is less than the preset change value;

[0097] Subtracting the pH change value from the preset change value to obtain a change difference;

[0098] A number of molecular weight optimization coefficients corresponding to the variation differences are set to optimize the implemented molecular weight.

[0099] Specifically, sodium alginate and chitosan can accelerate degradation under acidic soil conditions, while PLA will slow down degradation under neutral soil conditions. The lactic acid bacteria in the embodiments of the present invention are typical acid-producing microorganisms that directly reduce the soil pH by fermenting sugars to produce lactic acid. The metabolic products of yeast are mainly carbon dioxide and water. Some strains (such as Saccharomyces cerevisiae) can produce a small amount of organic acid, but its effect on soil pH is relatively weak. Bacillus subtilis converts organic nitrogen into ammonia through ammoniation, and ammonia dissolves in water to generate NH4 + , which can slightly increase the pH value. It is understandable that the late degradation of the quick-release layer material and the entire degradation process of the sustained-release layer material may be accelerated because lactic acid bacteria ferment sugars to lower the pH value of the soil environment, while the degradation rate of the quick-release layer material and the long-acting layer material is not affected by changes in soil pH value.

[0100] Specifically, the value of the preset pH value change is determined according to the historical degradation process, and the specific value range is set to [0.3, 0.8]. In the embodiment of the present invention, 0.4 is preferred.

[0101] Specifically, the change difference is compared with a preset difference;

[0102] Determining to increase the implemented molecular weight by a first molecular weight optimization coefficient based on a comparison result that the change difference is greater than the preset difference;

[0103] Based on the comparison result that the change difference is less than or equal to the preset difference, it is determined to increase the implemented molecular weight by a second molecular weight optimization coefficient.

[0104] Specifically, the value of the preset difference is determined according to the historical degradation process, and the specific range is set to [0.05, 0.12], and the embodiment of the present invention preferably is 0.07; it can be understood that in the embodiment of the present invention, the molecular weight is optimized according to the pH value only for the sustained-release layer material chitosan, and the value range of the first molecular weight optimization coefficient is set to [1.07, 1.12], and the embodiment of the present invention preferably is 1.1, and the value range of the second molecular weight optimization coefficient is set to [1.02, 1.06], and the embodiment of the present invention preferably is 1.04.

[0105] In practice, the adjustment process of the initial molecular weight is that the product of the initial molecular weight and the corresponding molecular weight optimization coefficient is the implemented molecular weight.

[0106] See also Figure 4 As shown, it is a schematic structural diagram of the composite microbial soil conditioner according to an embodiment of the present invention.

[0107] The embodiment of the present invention also provides a composite microbial soil conditioner prepared using the composite microbial soil conditioner preparation method, comprising: 85-93 parts of composite microorganisms, 1-3 parts of pyrocatechol, 1-3 parts of an ammonia stabilizer, and 2-6 parts of polyglutamic acid.

[0108] Specifically, the composite microorganism includes 80 to 100 parts of a quick-release layer, 90 to 110 parts of a sustained-release layer and 100 to 120 parts of a long-acting layer. The quick-release layer includes 25 to 35 parts of green algae, 15 to 25 parts of yeast, 3 to 6 parts of sucrose, 8 to 10 parts of volcanic ash and 8 to 10 parts of humic acid. The sustained-release layer includes 30 to 40 parts of lactic acid bacteria, 10 to 12 parts of humic acid and 10 to 12 parts of volcanic ash. The long-acting layer includes 35 to 50 parts of Bacillus subtilis, 30 to 40 parts of biochar and 15 to 30 parts of bentonite.

[0109] Specifically, the composite microbial soil conditioner is a three-layer embedding material, the outer layer is a quick-release layer 1, the middle layer is a slow-release layer 2, and the inner layer is a long-acting layer 3.

[0110] Specifically, the embedding material of the immediate-release layer 1 is sodium alginate gel, the embedding material of the sustained-release layer 2 is chitosan, and the embedding material of the long-acting layer 3 is polylactic acid-glycolic acid copolymer.

[0111] Specifically, the preparation process of the composite microorganism in the embodiment of the present invention is as follows:

[0112] Preparation of immediate-release layer 1:

[0113] Sodium alginate was prepared using the calcium ion cross-linking method. 2 g of sodium alginate powder with a molecular weight of 80 kDa was completely dissolved in 100 mL of distilled water, and then ultrasonically degassed to obtain a sodium alginate solution.

[0114] Green algae (Chlorella) and yeast are activated to prepare green algae suspension and yeast suspension respectively. The activation method is a prior art and will not be described in detail here.

[0115] Dissolve 1 g of food-grade sucrose in 20 mL of sterile water to prepare a 5% (w / v) sterile solution. Grind the volcanic ash and humic acid through a 100-mesh sieve, rinse three times with deionized water, dry at 105°C to constant weight, and sterilize.

[0116] Green algae suspension (10 mL), yeast suspension (5 mL), sucrose solution (10 mL), and volcanic ash (5 g) were added to sodium alginate solution (80 mL), and magnetic stirring was performed for 20 min to ensure uniform dispersion to obtain a mixed solution;

[0117] The mixed solution was slowly dripped into the CaCl2 solidification solution (concentration 0.8% w / v, volume 50 mL) through a syringe (needle inner diameter 0.8 mm) at a dripping speed of 5 to 8 drops / min. The droplets stayed in the CaCl2 solution for 8 to 10 minutes to form microspheres with a diameter of 200 to 300 μm.

[0118] The microspheres were centrifuged, washed three times with deionized water, and then pre-frozen at -50 °C for 2 h. They were then transferred to a vacuum freeze dryer (-40 °C, 0.1 mbar) and dried for 12 h to obtain dry microspheres.

[0119] The dried microspheres were soaked in a suspension prepared with volcanic ash and humic acid in a ratio of 1:1 and ultrasonicated for 5 minutes. The suspension concentration was 5% w / v. After soaking, the microspheres were dried again in a vacuum freezer to obtain a quick-release layer material.

[0120] Preparation of sustained-release layer 2:

[0121] 3 g of chitosan powder with a molecular weight of 100 kDa was weighed, added to 100 mL of 1% acetic acid solution (pH 4.5-5.0), stirred magnetically (300 rpm) at 40°C for 2 hours until completely dissolved, and degassed by ultrasonication (40 kHz, 10 min).

[0122] The lactic acid bacteria are activated to obtain a lactic acid bacteria suspension. The activation process is a prior art and will not be described in detail here.

[0123] Humic acid powder was passed through a 100-mesh sieve and dissolved in deionized water to a concentration of 1% w / v, and sterilized.

[0124] Lactobacillus suspension (5 mL) and humic acid solution (10 mL) were added to chitosan solution (80 mL) and magnetically stirred (200 rpm) for 20 min to ensure uniform dispersion;

[0125] The prepared quick-release layer microspheres (10 g) were added to the chitosan-lactic acid bacteria-humic acid mixture and ultrasonically treated to uniformly disperse the microspheres in the chitosan solution;

[0126] Chitosan solution was dropped into glutaraldehyde curing solution (concentration 0.3% to 0.5% w / v, volume 100 mL) for 10 to 15 min;

[0127] The microspheres were collected by centrifugation, washed three times with sterile deionized water, and freeze-dried (pre-frozen at -50°C for 2 hours, vacuum degree <10 Pa) to constant weight to obtain double-layer embedded microspheres.

[0128] Preparation of long-lasting layer 3:

[0129] 60 g of PLA powder with a molecular weight of 150 kDa was weighed, 100 mL of dichloromethane (DCM) was added, and magnetic stirring (300 rpm) was performed for 2 h until the PLA was completely dissolved to obtain a PLA solution;

[0130] The biochar was ground through a 100-mesh sieve, washed three times with deionized water, dried at 105 °C to constant weight, and sterilized (121 °C, 15 min);

[0131] 10 g of double-layer embedded microspheres were added to the PLA solution to obtain a mixed slurry, which was then ultrasonically treated;

[0132] The mixed slurry was slowly dripped into the PLA curing liquid (dichloromethane:ethanol=3:1, volume ratio) using a syringe with a needle inner diameter of 0.8 mm at a dripping speed of 3-5 drops / minute. The droplets stayed in the curing liquid for 10-15 minutes to form three-layer microspheres with a diameter of 300-500 μm (the outer layer was the PLA sustained-release layer, the middle layer was the sustained-release layer microspheres, and the inner layer was the immediate-release layer microspheres);

[0133] The three-layer microspheres were collected by centrifugation, washed three times with deionized water, pre-frozen at -50°C for 2 hours, transferred to a vacuum freeze dryer (-40°C, 0.1 mbar) for 12 hours, and irradiated with gamma rays (dose 15 kGy) to ensure sterility to obtain composite microorganisms.

[0134] The process of preparing composite microbial soil conditioner is as follows:

[0135] Taking 100g of the composite microbial soil conditioner as an example, 91g of the composite microorganism, 3g of pyrocatechol, 1g of the ammonia stabilizer, and 5g of polyglutamic acid are physically mixed to obtain the composite microbial soil conditioner.

[0136] Specifically, the composite microorganisms (yeast, lactic acid bacteria and Bacillus subtilis) are fixed by three-layer embedding technology to form a stable microsphere structure, which prolongs the survival period of microorganisms in the soil and ensures their efficient colonization in the rhizosphere. Among them: yeast produces CO2 and organic acids by decomposing soil organic matter, releasing potential nutrients in the soil and providing a direct carbon source for plants; lactic acid bacteria metabolize to produce organic acids such as lactic acid and acetic acid, lowering the pH value of the soil and inhibiting the reproduction of soil-borne pathogens such as Fusarium and Penicillium; Bacillus subtilis secretes hydrolases such as cellulase and chitinase to decompose insoluble phosphorus and difficult-to-degrade organic matter (such as pesticide residues), and at the same time produces antibacterial substances (such as lipopeptide antibiotics) to antagonize soil-borne pathogens (such as root-knot nematodes and wilt pathogens); pyrocatechol, as a natural polyphenol compound, inhibits the metabolic activity of harmful microorganisms in the soil (such as Escherichia coli and Salmonella) through redox reactions, reducing the damage of their secreted toxins (such as enterotoxins and aflatoxins) to plant roots; at the same time, its Weak acidity can neutralize some alkaline substances, assist lactic acid bacteria in adjusting the soil pH to slightly acidic, and create a "low-toxic, acidic" growth environment for crop roots; ammonia stabilizers chelate ammonium nitrogen in the soil, inhibit its conversion to nitrate nitrogen, significantly reduce nitrogen volatilization losses, and increase the effective nitrogen content in the soil by 20% to 30%; at the same time, its weak alkalinity can neutralize some acidic substances, avoid excessive soil acidity, and balance the microbial metabolic environment; polyglutamic acid, as a high-molecular amino acid polymer, can combine with soil colloids (such as clay minerals and humus) through carboxyl groups to form a stable aggregate structure, thereby improving soil aeration and water holding capacity; the amino groups on its molecular chain can chelate with metal ions to form chelated nutrients that are easily absorbed by plants, thereby promoting the active absorption of nutrients by crop roots.

[0137] Example 1

[0138] 91 parts of composite microorganisms, 3 parts of pyrocatechol, 1 part of ammonia stabilizer, and 5 parts of polyglutamic acid were physically mixed to obtain 10 kg of composite microbial soil conditioner. Compared with the composite microbial soil conditioner in the embodiment of the present invention, a commercially available single-layer sodium alginate-encapsulated lactic acid bacteria agent and a commercially available organic fertilizer containing Bacillus subtilis encapsulated by a material were used respectively. They were applied to cotton crops according to the requirements of use. The comparison results are shown in the table. Table 1 Effects of different soil conditioners on soil physical and chemical properties and microbial activity during the cotton seedling stage (7th to 15th day)

[0139]

[0140] As can be seen from Table 1, the composite microbial soil conditioner produced by the embodiment of the present invention has better effects on soil pH, organic matter increment, available phosphorus, available nitrogen, bacterial survival rate and soil-borne disease inhibition rate than the single-layer encapsulated lactic acid bacteria and non-encapsulated Bacillus subtilis inoculants.

[0141] Table 2 Effects of different soil amendments on nutrient supply and crop growth during the cotton growth period (75th to 100th day)

[0142]

[0143]

[0144] As can be seen from Table 2, the composite microbial soil conditioner produced in the embodiment of the present invention has better effects on soil pH, available phosphorus increment, urease activity, plant height, bud number and bacterial survival rate compared with the control group.

[0145] Table 3 Effects of different soil amendments on soil health and yield during the flowering and fruiting period of cotton (120th to 150th day)

[0146]

[0147] As shown in Table 3, the composite microbial soil conditioner produced by the embodiment of the present invention has better effects on soil heavy metal passivation rate, soil aggregate stability, wilt disease incidence, seed cotton yield and fungus survival rate compared with the control group.

[0148] The soil conditioner provided in the embodiment of the present invention is propagated in the workshop so that it can be fermented in the soil, thereby activating the microorganisms in the soil to ferment the soil, thereby converting the soil environment into an environment where microorganisms can live well, thereby achieving the purpose of soil improvement.

[0149] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a composite microbial soil conditioner, characterized in that: include: Determining the release duration of a single bacterial species based on a single growth cycle of the crop to determine the initial molecular weight of the embedding layer of the single bacterial species, and embedding the target bacterial species according to the initial molecular weight to obtain a plurality of embedded bacterial species; Placing the embedded bacteria in a preset degradation environment to determine the incubation time of the target bacteria to determine whether the initial molecular weight of the embedded layer is qualified, and adjusting the initial molecular weight according to the degradation rate of the embedded layer to obtain the implemented molecular weight; Determining an embedding order of several bacterial species based on the growth cycle of the crop, and embedding several target bacterial species according to the embedding order to prepare a composite microorganism; Placing the composite microorganism in a preset degradation environment to determine the overlap of release times of several bacterial species to determine whether the release process of the composite microorganism is qualified, and determining the release time of a single bacterial species if the release process of the composite microorganism is determined to be unqualified, so as to optimize the implementation molecular weight based on changes in the degradation environment during the release process of a previous layer of bacterial species adjacent to the bacterial species with unqualified release time; The optimized composite microorganism is mixed with other ingredients in proportion to obtain a composite microbial soil conditioner, wherein the other ingredients include pyrocatechol, an ammonia stabilizer and polyglutamic acid.

2. The method for preparing the composite microbial soil conditioner according to claim 1, characterized in that: The process of determining whether the initial molecular weight of the encapsulation layer is qualified based on the incubation time of the target bacterial species includes: Comparing the latency periods with preset latency periods respectively; Determining that the initial molecular weight of the embedding layer is unqualified based on a comparison result that the incubation time is less than a first preset incubation time or greater than a second preset incubation time; The second preset latency period is greater than the first preset latency period.

3. The method for preparing the composite microbial soil conditioner according to claim 2, characterized in that: Under the condition that the initial molecular weight is determined to be unqualified, the process of adjusting the initial molecular weight according to the degradation rate of the embedding layer includes: comparing the degradation rates with preset rates respectively; Based on the comparison result that the degradation rate is less than the first preset rate, subtracting the first preset rate from the degradation rate to obtain a first rate difference value, or based on the comparison result that the degradation rate is greater than the second preset rate, subtracting the degradation rate from the first preset rate to obtain a second rate difference value; A plurality of molecular weight adjustment coefficients corresponding to the first rate difference and the second rate difference are provided to adjust the initial molecular weight according to the molecular weight adjustment coefficients.

4. The method for preparing the composite microbial soil conditioner according to claim 3, wherein: The process of determining whether the release process of the composite microorganism is qualified according to the overlap of the release time of several target strains includes: comparing the overlap degrees with preset overlap degrees respectively; Determining that the release process of the composite microorganism is unqualified based on a comparison result that the overlap is less than a first preset overlap or greater than a second preset overlap; The second preset overlap is greater than the first preset overlap.

5. The method for preparing the composite microbial soil conditioner according to claim 4, characterized in that: Under the condition that the release process of the composite microorganisms is determined to be unqualified, the process of determining whether the release time of a single target bacterial species is qualified includes: Comparing the release durations with preset release durations respectively; Determining that the release time of the single target bacterial species is unqualified based on a comparison result that the release time is less than the first preset release time or the release time is greater than the second preset release time; The second preset release time is greater than the first preset release time.

6. The method for preparing the composite microbial soil conditioner according to claim 5, characterized in that: Under the condition that the release time of a single target bacterial species is determined to be unqualified, the process of optimizing the molecular weight according to the pH change of the degradation environment during the release process of the target bacterial species in the previous layer adjacent to the target bacterial species includes: comparing the pH change value with a preset change value; Determining to optimize the implemented molecular weight based on a comparison result that the pH value change value is greater than or equal to a preset change value; Subtracting the pH change value from the preset change value to obtain a change difference; A number of molecular weight optimization coefficients corresponding to the variation differences are set to optimize the implemented molecular weight.

7. The composite microbial soil conditioner prepared by the method for preparing the composite microbial soil conditioner according to any one of claims 1 to 6, characterized in that: include: 85-93 parts of composite microorganisms, 1-3 parts of pyrocatechol, 1-3 parts of ammonia stabilizer, and 2-6 parts of polyglutamic acid.

8. The composite microbial soil conditioner according to claim 7, characterized in that The composite microorganism includes 80-100 parts of a quick-release layer, 90-110 parts of a sustained-release layer and 100-120 parts of a long-acting layer. The quick-release layer includes 25-35 parts of green algae, 15-25 parts of yeast, 3-6 parts of sucrose, 8-10 parts of volcanic ash and 8-10 parts of humic acid. The sustained-release layer includes 30-40 parts of lactic acid bacteria, 10-12 parts of humic acid and 10-12 parts of volcanic ash. The long-acting layer includes 35-50 parts of Bacillus subtilis, 30-40 parts of biochar and 15-30 parts of bentonite.

9. The composite microbial soil conditioner according to claim 8, characterized in that The composite microbial soil conditioner is a three-layer embedding material, wherein the outer layer is a quick-release layer, the middle layer is a slow-release layer, and the inner layer is a long-acting layer.

10. The composite microbial soil conditioner according to claim 9, characterized in that The embedding material of the quick-release layer is sodium alginate gel, the embedding material of the sustained-release layer is chitosan, and the embedding material of the long-acting layer is polylactic acid-glycolic acid copolymer.

Images