CN117964421A

CN117964421A - Synergistic improver for saline-alkali soil and preparation method thereof

Info

Publication number: CN117964421A
Application number: CN202410130429.6A
Authority: CN
Inventors: 闫苧; 李世华; 李世峰; 关立元
Original assignee: Inner Mongolia Xingnong Future Science And Technology Development Center LP
Current assignee: Inner Mongolia Xingnong Future Science And Technology Development Center LP
Priority date: 2024-01-31
Filing date: 2024-01-31
Publication date: 2024-05-03

Abstract

The invention discloses a soil synergistic improver for saline-alkali soil and a preparation method thereof, belonging to the technical field of soil improvement, and comprising the following components: wormcast fermentation liquor, composite probiotics microcapsule, modified zeolite-vermiculite, modified chitosan, amino acid, vitamin, biological glycolipid, nano potassium humate, calcium superphosphate, gamma-polyglutamic acid and nitrification inhibitor. According to the invention, the stability of microorganisms is realized by coating the composite flora with carboxymethyl cellulose and sodium alginate, so that the technical effects of improving soil ventilation condition and improving resistance of plants to pathogenic microorganisms are realized, and meanwhile, the stability and water absorption of the modifier are improved by adding modified chitosan obtained by loading urea formaldehyde into carboxymethyl chitosan super absorbent resin, so that the technical effects of slow release of the modifier and soil water and fertilizer retention are realized.

Description

Synergistic improver for saline-alkali soil and preparation method thereof

Technical Field

The invention belongs to the technical field of soil improvement, and particularly relates to a soil synergistic improver for saline-alkali soil and a preparation method thereof.

Background

The saline-alkali soil refers to soil with too high salinity and alkalinity, the saline-alkali soil is hardened soil from the aspect of soil structure, the air permeability and the water permeability of the soil are poor, the soil environment severely limits the growth of crops, the agricultural production is seriously influenced, the saline-alkali soil is reasonably developed and effectively utilized, the problem of insufficient farmland in agricultural production in China can be effectively relieved, and in order to solve the problem of the saline-alkali soil, people aim to find effective synergistic modifier to improve the soil structure of the saline-alkali soil and improve the soil fertility, so that the saline-alkali soil can also carry out agricultural production; some natural materials and chemical substances have an improvement effect on the saline alkali soil, lime, gypsum, organic substances and the like can neutralize the alkalinity of the soil, reduce the salt content in the soil and improve the soil structure, however, the traditional improving agents have limited effects in improving the soil fertility and improving the soil structure; in recent years, some novel saline-alkali soil synergistic improving agents are researched and applied, for example, porous materials, hydrogel, polymers and other materials are introduced into the saline-alkali soil improvement, and the materials have good water and fertilizer retention performance, can improve the water and fertilizer retention capacity of soil, reduce the damage of salt to plants and promote plant growth.

However, the existing saline-alkali soil synergistic modifier has the following problems: 1. the modifier has poor stability and is easy to lose activity in bad soil; 2. the modifier has poor slow release performance and low bioavailability; 3. improving the water and fertilizer retaining capability of soil.

Disclosure of Invention

Aiming at the situation, the invention provides a synergistic modifier for saline-alkali soil and a preparation method thereof, aiming at overcoming the defects of the prior art, and aiming at solving the problems that the stability and the sustained release performance of the modifier are poor and the soil water and fertilizer retaining capacity is improved, the invention provides a mode of coating a composite flora by carboxymethyl cellulose and sodium alginate to realize the stability of microorganisms, further realize the technical effects of improving the ventilation condition of the soil and improving the resistance of plants to pathogenic microorganisms, and simultaneously add modified chitosan obtained by loading urea formaldehyde into carboxymethyl chitosan super absorbent resin to improve the stability and the water absorption of the modifier, thereby realizing the slow release of the modifier and the technical effects of soil water and fertilizer retaining.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the invention provides a synergistic improver for saline-alkali soil, which comprises the following components in parts by weight: 100-150 parts of wormcast fermentation liquor, 8-10 parts of composite probiotics microcapsule, 50-80 parts of modified zeolite-vermiculite, 10-20 parts of modified chitosan, 3-5 parts of amino acid, 3-5 parts of vitamin, 5-7 parts of biological glycolipid, 10-15 parts of nano potassium humate, 10-15 parts of superphosphate, 1-2 parts of gamma-polyglutamic acid and 1-2 parts of nitrification inhibitor;

preferably, the wormcast fermentation liquid is obtained by mixing and fermenting wormcast and an activated microbial agent, and filtering and removing impurities;

preferably, the composite probiotic microcapsule comprises a microcapsule core material and a wall material;

Preferably, the core material comprises an activated complex population coated with soybean oil;

preferably, the wall material comprises a carboxymethyl cellulose and sodium alginate composite film;

Preferably, the modified zeolite-vermiculite is obtained by crushing, mixing and calcining zeolite and vermiculite, and modifying by octadecyl trimethyl ammonium bromide and lanthanum chloride;

preferably, the modified chitosan is obtained by loading urea formaldehyde into carboxymethyl chitosan super absorbent resin;

preferably, the amino acid is selected from at least one of lysine, methionine, threonine, tryptophan and glycine;

Amino acid is an essential element for plant growth, can reduce the toxicity of salt in saline-alkali soil, can be combined with the salt to form soluble hydrochloride or hydrochloride complex, improves the solubility of the salt in the soil, promotes the release and migration of the salt, reduces the influence of saline-alkali stress on plants, and reduces the damage to the plants.

Preferably, the vitamin is selected from at least one of vitamin a, vitamin C, vitamin E, vitamin B1 and vitamin B3;

the vitamins have the anti-oxidation capability, can reduce the oxidative damage of salt to plant cells, protect the integrity of chloroplasts and cell membranes, activate the defense system of plants, and strengthen the anti-oxidation capability and the anti-virus capability of the plants.

Preferably, the biological glycolipid is selected from at least one of rhamnolipids, xylolipids, sophorolipids and trehalose lipids;

The biological glycolipid has good water retention, can increase the water retention capacity of soil, reduce the loss of soil moisture, is beneficial to the growth of crops, can promote the crystallization of salt in the soil, reduce the damage of the salt to plants and improve the physical properties of the soil; the soil aggregate stability can be improved, the soil structure can be improved, the soil air permeability and the permeability can be improved, and the growth of plant roots can be promoted.

Preferably, the nitrification inhibitor is selected from at least one of 4-dimethylaminopyridine, 3, 4-dimethylpyrazole phosphate, dicyandiamide and 2-chloro-6- (trichloromethyl) pyridine;

The nitrification inhibitor can inhibit the oxidative conversion of ammonia nitrogen in soil to nitrate, so that the nitrification process of the nitrogen fertilizer is delayed, the formation of nitrate is reduced, the loss of the nitrogen fertilizer is reduced, the utilization rate of the nitrogen fertilizer is improved, and the pollution to the environment is reduced.

The nano potassium humate contains rich organic matters, has extremely strong ion exchange capability, can adsorb salt ions in soil, lightens the influence of salt on plants, contains organic acid, can react with alkaline salt in soil, neutralizes the alkalinity of the soil, adjusts the pH value of the soil, is more suitable for plant growth, contains humus and various microelements, and has a promoting effect on plant growth.

The gamma-polyglutamic acid is a biodegradable high molecular polymer, improves the water retention performance of soil, is beneficial to improving the texture and structure of the soil, and provides water required by plants.

Preferably, the preparation method of the wormcast fermentation liquid specifically comprises the following steps:

Removing impurities from wormcast, crushing, sieving with a 20-mesh sieve, stirring wormcast while spraying a calcium chloride aqueous solution, standing for 3h, eluting with tap water, drying at 50 ℃ until the water content is 50%, inoculating activated composite flora, adjusting pH to 6.0, fermenting in a sealed fermentation tank at 30-34 ℃ for 3-5d to obtain a fermentation product, and filtering with a 80-mesh sieve to obtain wormcast fermentation liquor;

Preferably, the mass fraction of the calcium chloride aqueous solution is 2-3%;

preferably, the addition amount of the compound probiotics is 3-5% of the weight of the wormcast.

Wormcast is a substance excreted after earthworm digestion, is rich in organic matters and microorganisms, can provide rich nutrients and beneficial microorganisms for soil, promotes the biological activity of the soil, and improves the fertility of the soil; organic substances in the wormcast can chemically react with salt in the soil, so that the saline alkali degree of the soil can be reduced; the calcium chloride aqueous solution spray can help to reduce volatilization of ammonia in wormcast, reduce influence of odor on surrounding environment, and promote microbial decomposition in livestock manure fertilizer, and the calcium chloride can be used as neutral salt and can also adjust pH value of soil.

Preferably, the preparation method of the activated complex bacterial colony specifically comprises the following steps:

Inoculating Klebsiella oxytoca and Bacillus bailii respectively into Gao's medium for activation culture, wherein the activation temperature is 28-32 ℃, the activation time is 2-3d, shaking culture is carried out until the bacterial content is O.D600 approximately equal to 2.0, mixing is carried out according to the volume ratio of 1:1, and drying is carried out, thus obtaining an activated composite bacterial colony;

Preferably, the number of viable bacteria of the klebsiella oxytoca is more than 1.2×10 ⁷ CFU/g; the number of the bacillus bailii viable bacteria is more than 2.0X10 ⁸ CFU/g.

Preferably, the preparation method of the modified zeolite-vermiculite specifically comprises the following steps:

Pulverizing zeolite and vermiculite respectively, sieving with 50 mesh sieve, placing in a muffle furnace, purging under argon atmosphere with aeration rate of 0.1-0.2L/min, maintaining heating rate of 15-20deg.C/min, heating to 120-130deg.C, calcining for 4-6 hr, and cooling to room temperature to obtain activated zeolite and activated vermiculite; mixing 5g/L lanthanum chloride solution and 8g/L octadecyl trimethyl ammonium bromide solution to obtain mixed solution, adding activated zeolite and activated vermiculite, regulating pH to 9.0-10.0, centrifuging at 5000r/min for 10min, filtering, washing solid product with deionized water, and drying in a constant temperature oven at 110deg.C for 4 hr to obtain modified zeolite-vermiculite;

Preferably, the volume ratio of the lanthanum chloride solution to the octadecyl trimethyl ammonium bromide solution is 1:3-5;

Preferably, the solid-to-liquid ratio of the zeolite, the vermiculite and the mixed solution is 1:1:40-50.

The zeolite is alkaline hydrated aluminosilicate, the vermiculite is natural silicate clay mineral, the zeolite and the vermiculite have larger surface area, higher water retention and cation exchange capacity, and the zeolite-vermiculite modified by the lanthanum chloride solution and the octadecyl trimethyl ammonium bromide solution can improve the ion exchange capacity of soil, is beneficial to adsorbing and releasing nutrients in the soil and improves the fertility of the soil; the modified zeolite-vermiculite can adsorb heavy metal ions and other harmful substances in soil, so that the toxic action of the modified zeolite-vermiculite on plant growth is reduced; the modified zeolite-vermiculite has a porous structure, can provide a nutrient environment for microorganism growth, promotes growth and propagation of beneficial microorganisms in soil, and is beneficial to balance of a soil ecosystem.

Preferably, the preparation method of the modified chitosan specifically comprises the following steps:

① Adding urea into formaldehyde solution with the mass concentration of 35%, stirring for 30min at the rotating speed of 200r/min, uniformly mixing, adjusting the pH value to 9.0 by using 1moL/L sodium hydroxide solution, heating to 50 ℃ for reaction for 2h, adjusting the pH value to 5.0 by using 1moL/L hydrochloric acid solution, continuing to react for 1h, drying by using a constant-temperature oven at 60 ℃ for 6h, and grinding into powder to obtain urea formaldehyde;

② Adding chitosan into isopropanol, swelling for 30min, adding 50mL of 10mo/L sodium hydroxide solution, adding for 6 times, stirring for 1 hour at intervals of 20min each time at the rotating speed of 300r/min, adding 24g of monochloroacetic acid for 3 times, continuing to react for 3 hours at 60 ℃, regulating the pH to 7.0 by using glacial acetic acid after the reaction, filtering, washing a solid product with 70% methanol solution by mass concentration, drying for 4 hours by using a constant-temperature oven at 60 ℃, and grinding into powder to obtain carboxymethyl chitosan;

③ Adding carboxymethyl chitosan into deionized water to obtain carboxymethyl chitosan solution with the mass fraction of 10%, heating to 50 ℃ under nitrogen atmosphere, adding potassium persulfate, reacting for 10min, sequentially adding urea formaldehyde, acrylic acid solution, acrylamide and N, N' -methylene bisacrylamide, heating to 70 ℃ at the heating rate of 5 ℃/min, continuing to react for 3h, filtering, washing the solid product with ethanol solution with the mass concentration of 85%, and drying in a constant-temperature oven at the temperature of 100 ℃ for 3h to obtain modified chitosan;

Preferably, in step ①, the mass ratio of urea to formaldehyde solution is 1:1.5-2;

Preferably, in step ②, the mass to volume ratio of chitosan to isopropanol is 10-12g:200ml;

Preferably, in step ③, the mass ratio of chitosan, potassium persulfate, urea formaldehyde, acrylamide and N, N' -methylenebisacrylamide is 10-20:0.5-0.7:20-30:1-2:3-5;

preferably, the mass volume ratio of the carboxymethyl chitosan to the acrylic acid solution is 10-20g to 100mL;

Preferably, the mass concentration of the acrylic acid solution is 85%.

The invention also provides a preparation method of the soil synergistic improver for the saline-alkali soil, which comprises the following steps:

S1, dispersing activated composite flora in soybean oil, filtering and drying to obtain a composite probiotic microcapsule core material; dissolving carboxymethyl cellulose in deionized water, homogenizing for 10-15min at 10000r/min, adding composite probiotic microcapsule core material, and mixing to obtain composite solution; dissolving sodium alginate in deionized water, homogenizing at 10000r/min for 10-15min, and spray drying to obtain composite probiotic microcapsule;

s2, adding the composite probiotics microcapsule, modified zeolite-vermiculite, amino acid, vitamin, biological glycolipid, nano potassium humate, gamma-polyglutamic acid, nitrification inhibitor and calcium superphosphate into the wormcast fermentation broth, and uniformly stirring and mixing to obtain a pretreatment modifier;

s3, adding modified chitosan and glutaraldehyde into the pretreatment modifier, stirring and mixing uniformly, centrifugally separating for 1-2h at the rotating speed of 8000-12000r/min, collecting a lower-layer precipitate, washing the precipitate with normal saline with the mass fraction of 0.8-0.85% after sterilization, drying, granulating, and carrying out steam curing to obtain the soil synergistic modifier for the saline-alkali soil;

preferably, in step S1, the spray drying conditions are: the air inlet temperature is 160-180 ℃, the air outlet temperature is 80-90 ℃ and the flow rate is 15-20mL/min;

Preferably, in the step S2, the steam curing is to put the materials into a steam curing box with the temperature of 80-100 ℃ and the relative humidity of 60-70%, heat up to 90-110 ℃ at the speed of 15-25 ℃/h, and steam cure for 5-7h;

preferably, in the step S3, the mass ratio of the modified chitosan to glutaraldehyde is 10-20:0.1.

The beneficial effects obtained by the invention are as follows:

according to the invention, wormcast fermentation liquor is used as an improver liquid matrix, and is compounded with the composite probiotic microcapsule, the modified zeolite-vermiculite and the modified chitosan, and amino acid, vitamin, biological glycolipid, a nitrification inhibitor, nano potassium humate, calcium superphosphate and gamma-polyglutamic acid are added, so that the synergistic improver for the saline-alkali soil, which can improve the saline-alkali soil, can preserve fertilizer and water for a long time and has high stability, is obtained.

1. The composite probiotics microcapsule comprises a microcapsule core material and a wall material, wherein the core material comprises a composite flora of activated klebsiella oxytoca and bacillus berryis coated by soybean oil, the wall material comprises inner membrane carboxymethyl cellulose and outer membrane sodium alginate, the klebsiella oxytoca is a gram negative bacterium, belongs to the genus klebsiella, can generate organic acid such as lactic acid and acetic acid, can promote the decomposition of organic substances, converts the acetic acid in the organic substances into acetaldehyde and carbon dioxide which are easier to be absorbed and utilized by plants, is beneficial to improving the decomposition speed and nutrient release of organic substances in soil, can release carbon dioxide in the metabolic process of the klebsiella oxytoca, promotes the respiration in soil, is beneficial to improving the ventilation condition of soil, improves the ventilation property of soil, and can promote the maturation of wormcast fertilizer in the process of wormcast fermentation, so that the nutrients in wormcast are easier to be absorbed and utilized by plants; bacillus bailii can induce plants to produce plant defensins, wherein the plant defensins comprise antibacterial proteins, enzymes and signal molecules, can help the plants resist attack of pathogenic bacteria, pests and adverse environments, can strengthen the immunity of the plants, and can improve the resistance of the plants to pathogenic microorganisms, so that the harm of the pathogenic bacteria to the plants is reduced; the synergistic effect of the Klebsiella oxytoca and the Bacillus bailii is beneficial to regulating the pH value of soil, promoting the decomposition and conversion of organic matters and improving the structure and fertility of the soil; the activated composite flora is dispersed in the soybean oil, so that microorganisms can be protected from the influence of external environment, the soybean oil is rich in unsaturated fatty acids such as linoleic acid and linolenic acid, and nutrient components such as vitamin E and the like, the soybean oil can be used as nutrient sources of the flora, energy and nutrient substances required by growth are provided, the reproduction and the growth of the flora are promoted, the activated composite flora is used as a core material, an amphiphilic carboxymethyl cellulose is used as an inner film to form a microcapsule structure to cover the core material, the compatibility of the soybean oil and a wall material is increased, a protective film is formed, microorganisms and the external environment are effectively isolated, the microorganism strains are prevented from being influenced by the factors such as temperature, illumination, acid and alkali, the stability of the microorganism strains is improved, sodium alginate is used as an outer film of the microcapsule, the sodium alginate can absorb moisture, the moisture retention of the microcapsule is improved, the microorganism strains are prevented from being inactivated in a dry environment, in addition, the sodium alginate can also form a net structure, the stability and the mechanical strength of the microcapsule are increased, and the core material is slowly released;

2. According to the modified chitosan, urea formaldehyde is loaded into carboxymethyl chitosan super absorbent resin, carboxyl in carboxymethyl chitosan is connected with amino in urea formaldehyde through covalent bonds, so that carboxymethyl chitosan molecules are crosslinked, a three-dimensional network structure is formed, urea formaldehyde and carboxymethyl chitosan are firmly connected through crosslinking, immobilized loading of urea formaldehyde in carboxymethyl chitosan is realized, and the modified chitosan is added into a modifier, so that on one hand, interaction between the modified chitosan and other active substances in the modifier is beneficial to improving the water and fertilizer retention performance and the nutrient slow release performance of the modifier, on the other hand, the chitosan is used as the only alkaline polysaccharide in natural polysaccharide, has excellent film forming performance, forms a layer of protective film on the outer surface of a soil modifier, improves the stability of the modifier, and in addition, the chitosan also has antibacterial property, oxidation resistance and biodegradability, is beneficial to improving the disease resistance of soil and reduces the damage of crops from diseases and pests; the modified chitosan is obtained by firstly obtaining carboxymethyl chitosan, then sequentially adding potassium persulfate, urea formaldehyde, an acrylic acid solution, acrylamide and N, N' -methylene bisacrylamide into carboxymethyl chitosan solution, wherein the potassium persulfate is used as an initiator, and the potassium persulfate is decomposed to generate free radicals under the heating condition to promote the urea formaldehyde to be loaded into the carboxymethyl chitosan; acrylic acid is subjected to conjugate addition reaction with carboxyl in carboxymethyl chitosan, acrylic acid groups are introduced to provide active sites, the reaction capacity of the carboxymethyl chitosan is improved, the grafting reaction of the carboxymethyl chitosan and urea formaldehyde is further promoted, and in addition, hydroxyl groups in acrylic acid molecules and the groups can increase the hydrophilicity of the carboxymethyl chitosan; the acrylamide and amino or hydroxyl in the carboxymethyl chitosan are subjected to condensation reaction, and an acrylamide group is introduced, so that the carboxymethyl chitosan has better solubility and better water-phase solubilizing property, the adsorption performance of the carboxymethyl chitosan is improved, and the adsorption of heavy metals is facilitated by-NH ₂ and-OH in the molecule; n, N' -methylene bisacrylamide is a cross-linking agent, can react with acrylamide to form a cross-linking structure, can increase the inter-molecular chain connection of carboxymethyl chitosan, and further improves the stability and mechanical property of carboxymethyl chitosan; the modified chitosan is added into the soil conditioner, so that the technical effects of water and fertilizer retention can be realized, and the stability and nutrient slow release performance of the soil conditioner can be improved;

3. According to the invention, by using wormcast as a main active ingredient of the modifier, waste is fully and reasonably utilized, the environment is protected, the cost is saved, and the sustainable development concept is met; the synergistic modifier for the saline-alkali soil has the advantages of synergistic effect of all components, capability of improving water and fertilizer retention capability and organic matter content of soil, capability of improving air permeability and permeability of the soil, capability of reducing pH and salt content of the soil, capability of enhancing adsorption of heavy metals and capability of enhancing immunity and disease resistance of crops, and high stability and nutrient slow release performance.

Drawings

FIG. 1 is a graph showing the stability results of the modifiers prepared in example 1 and comparative examples 1-3 according to the present invention, when stored for 7 days in different pH environments;

FIG. 2 is a graph showing the effect of the water absorption properties of the improvers prepared in examples 1 to 3 and comparative examples 1 to 3 according to the present invention;

FIG. 3 is a graph showing the cumulative release results of organic nutrients of the improvers prepared in examples 1 to 3 and comparative examples 3 to 6 according to the present invention;

FIG. 4 is a graph showing the effect of the improvers from example 1 and comparative examples 1-8 of the present invention on the nutritional quality of corn;

FIG. 5 is a scanning image of the modified chitosan prepared in example 1 of the present invention at 500 Xmagnification by electron microscopy.

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention; all other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

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. In addition, any methods and materials similar or equivalent to those described herein can be used in the present application. The preferred methods and materials described herein are illustrative only and should not be construed as limiting the application.

The experimental methods in the following examples are all conventional methods unless otherwise specified; the test materials and test strains used in the examples described below, unless otherwise specified, were commercially available.

The strain sources related to the invention are as follows:

klebsiella oxytoca Klebsiella oxytoca, strain number: CICC 24130 purchased from China center for type culture Collection;

Bacillus belicus Bacillus velezensis, strain number: CICC 20519 purchased from China center for type culture Collection of microorganisms;

example 1

100 Parts of wormcast fermentation liquor, 8 parts of composite probiotics microcapsule, 50 parts of modified zeolite-vermiculite, 10 parts of modified chitosan, 3 parts of lysine, 3 parts of vitamin A, 5 parts of rhamnolipid, 1 part of 4-dimethylaminopyridine, 10 parts of nano potassium humate, 10 parts of calcium superphosphate and 1 part of gamma-polyglutamic acid;

The preparation method of the wormcast fermentation liquid specifically comprises the following steps:

Removing impurities from 30g of wormcast, crushing, sieving with a 20-mesh sieve, stirring wormcast while spraying a calcium chloride aqueous solution with the mass fraction of 2%, standing for 3h, eluting with tap water, drying at 50 ℃ until the water content is 50%, inoculating activated composite flora, adjusting the pH to 6.0, placing in a sealed fermentation tank for fermentation at 30 ℃ for 3d to obtain a fermentation product, and filtering with a 80-mesh sieve to obtain wormcast fermentation liquor.

The preparation method of the activated composite flora specifically comprises the following steps:

inoculating klebsiella oxytoca and bacillus bailii into a Gao's culture medium for activation culture, wherein the activation temperature is 28 ℃, the activation time is 2d, shaking culture is carried out until the bacterial content is O.D600 approximately equal to 2.0, mixing is carried out according to the volume ratio of 1:1, and drying is carried out, thus obtaining the activated composite flora.

The preparation method of the modified zeolite-vermiculite specifically comprises the following steps:

respectively crushing 25g of zeolite and 25g of vermiculite, sieving with a 50-mesh sieve, placing in a muffle furnace, purging under argon atmosphere with the ventilation rate of 0.1L/min, keeping the heating rate at 15 ℃/min, heating to 120 ℃, calcining for 4 hours, and cooling to room temperature to obtain activated zeolite and activated vermiculite; mixing 10mL of lanthanum chloride solution with the mass concentration of 5g/L and 30mL of octadecyl trimethyl ammonium bromide solution with the mass concentration of 8g/L to obtain a mixed solution, adding activated zeolite and activated vermiculite, adjusting the pH value to 9.0, centrifuging for 10min at the rotating speed of 5000r/min, filtering, washing a solid product with deionized water, and drying in a constant temperature oven at 110 ℃ for 4h to obtain the modified zeolite-vermiculite.

The preparation method of the modified chitosan specifically comprises the following steps:

① Adding 20g of urea into 30mL of formaldehyde solution with mass concentration of 35%, stirring for 30min at a rotating speed of 200r/min, uniformly mixing, adjusting the pH to 9.0 by using 1moL/L sodium hydroxide solution, heating to 50 ℃ for reaction for 2h, adjusting the pH to 5.0 by using 1moL/L hydrochloric acid solution, continuing to react for 1h, drying for 6h by using a constant-temperature oven at 60 ℃, and grinding into powder to obtain urea formaldehyde;

② Adding 10g of chitosan into 200mL of isopropanol, swelling for 30min, adding 50mL of 10mo/L sodium hydroxide solution, adding 6 times, fully stirring at intervals of 20min each time at a rotating speed of 300r/min for 1 hour, adding 24g of monochloroacetic acid, adding 3 times, continuing to react at 60 ℃ for 3 hours, regulating the pH value to 7.0 by using glacial acetic acid after the reaction, filtering, washing a solid product by using a methanol solution with the mass concentration of 70%, drying by using a constant temperature oven at 60 ℃ for 4 hours, and grinding into powder to obtain carboxymethyl chitosan;

③ Adding carboxymethyl chitosan into deionized water to obtain carboxymethyl chitosan solution with the mass fraction of 10%, heating to 50 ℃ under nitrogen atmosphere, adding 0.5g of potassium persulfate, reacting for 10min, sequentially adding 20g of urea formaldehyde, 100mL of 85% acrylic acid solution, 1g of acrylamide and 3g of N, N' -methylenebisacrylamide, heating to 70 ℃ at the heating rate of 5 ℃/min, continuing to react for 3h, filtering, washing the solid product with ethanol solution with the mass concentration of 85%, and drying in a constant temperature oven at 100 ℃ for 3h to obtain the modified chitosan.

s1, dispersing 8g of activated composite flora in soybean oil, filtering and drying to obtain a composite probiotic microcapsule core material; 1g of carboxymethyl cellulose is dissolved in 100mL of deionized water, homogenized for 10min at the rotating speed of 10000r/min, and added with composite probiotic microcapsule core materials, and uniformly mixed to obtain composite liquid; dissolving 2g of sodium alginate in 30mL of deionized water, homogenizing for 10min at a rotating speed of 10000r/min, adding into the composite liquid, spray drying, and obtaining the composite probiotic microcapsule, wherein the air inlet temperature is 160 ℃, the air outlet temperature is 80 ℃, and the flow speed is 15 mL/min;

S2, adding 8g of composite probiotics microcapsule, 50g of modified zeolite-vermiculite, 3g of lysine, 3g of vitamin A, 5g of rhamnolipid, 10g of nano potassium humate, 1g of gamma-polyglutamic acid, 1g of 4-dimethylaminopyridine and 10g of calcium superphosphate into 100g of wormcast fermentation broth, and uniformly stirring and mixing to obtain a pretreatment modifier;

S3, adding 10g of modified chitosan and 0.1g of glutaraldehyde into the pretreatment modifier, stirring and mixing uniformly, centrifugally separating for 1h at the rotating speed of 8000r/min, collecting a lower-layer precipitate, washing the precipitate with normal saline with the mass fraction of 0.8% after sterilization, drying, granulating, placing the precipitate in a steam curing box with the temperature of 80 ℃ and the relative humidity of 60%, heating to 90 ℃ at the speed of 15 ℃/h, and steaming for 5h to obtain the soil synergistic modifier for the saline-alkali soil.

Example 2

125 Parts of wormcast fermentation liquor, 9 parts of composite probiotics microcapsule, 65 parts of modified zeolite-vermiculite, 15 parts of modified chitosan, 4 parts of methionine, 4 parts of vitamin C, 6 parts of xylo-lipids, 1.5 parts of 3, 4-dimethylpyrazole phosphate, 12.5 parts of nano potassium humate, 12.5 parts of calcium superphosphate and 1.5 parts of gamma-polyglutamic acid.

The preparation method of wormcast fermentation liquor, modified zeolite-vermiculite and modified chitosan is the same as in example 1.

S1, dispersing 9g of activated composite flora in soybean oil, filtering and drying to obtain a composite probiotic microcapsule core material; dissolving 2g of carboxymethyl cellulose in 100mL of deionized water, homogenizing for 12min at a rotating speed of 10000r/min, adding a composite probiotic microcapsule core material, and uniformly mixing to obtain a composite liquid; dissolving 2.5g of sodium alginate in 30mL of deionized water, homogenizing at 10000r/min for 12min, adding into the composite liquid, spray drying, and obtaining the composite probiotic microcapsule, wherein the air inlet temperature is 170 ℃, the air outlet temperature is 85 ℃, and the flow rate is 18 mL/min;

S2, adding 9g of composite probiotics microcapsule, 65g of modified zeolite-vermiculite, 4g of methionine, 4g of vitamin C, 6g of xylose grease, 12.5g of nano potassium humate, 1.5g of gamma-polyglutamic acid, 1.5g of 3, 4-dimethylpyrazole phosphate and 12.5g of calcium superphosphate into 125g of wormcast fermentation liquor, and uniformly stirring and mixing to obtain a pretreatment modifier;

S3, adding 15g of modified chitosan and 0.1g of glutaraldehyde into the pretreatment modifier, stirring and mixing uniformly, centrifugally separating for 1.5h at the rotating speed of 9000r/min, collecting a lower-layer precipitate, washing the precipitate with normal saline with the mass fraction of 0.82% after sterilization, drying, granulating, placing the precipitate in a steam curing box with the temperature of 90 ℃ and the relative humidity of 65%, heating to 100 ℃ at the speed of 18 ℃/h, and steaming for 6h to obtain the soil synergistic modifier for the saline-alkali soil.

Example 3

150 Parts of wormcast fermentation liquor, 10 parts of composite probiotics microcapsule, 80 parts of modified zeolite-vermiculite, 20 parts of modified chitosan, 5 parts of threonine, 5 parts of vitamin E, 7 parts of trehalose ester, 2 parts of 2-chloro-6- (trichloromethyl) pyridine, 15 parts of nano potassium humate, 15 parts of calcium superphosphate and 2 parts of gamma-polyglutamic acid.

S1, dispersing 10g of activated composite flora in soybean oil, filtering and drying to obtain a composite probiotic microcapsule core material; dissolving 3g of carboxymethyl cellulose in 100mL of deionized water, homogenizing for 15min at a rotating speed of 10000r/min, adding a composite probiotic microcapsule core material, and uniformly mixing to obtain a composite liquid; 3g of sodium alginate is dissolved in 30mL of deionized water, homogenized for 15min at the rotating speed of 10000r/min, added into the composite liquid, and spray dried, wherein the air inlet temperature is 180 ℃, the air outlet temperature is 90 ℃ and the flow speed is 20mL/min, so as to obtain the composite probiotic microcapsule;

S2, adding 10g of composite probiotics microcapsule, 80g of modified zeolite-vermiculite, 5g of threonine, 5g of vitamin E, 7g of trehalose ester, 15g of nano potassium humate, 2g of gamma-polyglutamic acid, 2g of 2-chloro-6- (trichloromethyl) pyridine and 15g of calcium superphosphate into 150g of wormcast fermentation liquor, and uniformly stirring and mixing to obtain a pretreatment modifier;

s3, adding 15g of modified chitosan and 0.1g of glutaraldehyde into the pretreatment modifier, stirring and mixing uniformly, centrifugally separating for 2 hours at the rotating speed of 10000r/min, collecting a lower-layer precipitate, washing the precipitate with normal saline with the mass fraction of 0.85% after sterilization, drying, granulating, placing the precipitate in a steam curing box with the temperature of 100 ℃ and the relative humidity of 70%, heating to 110 ℃ at the speed of 20 ℃/h, and steaming for 7 hours to obtain the soil synergistic modifier for the saline-alkali soil.

Comparative example 1

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which are different from example 1 only in that the composite probiotics are not coated with microcapsules, and the rest components, component contents and preparation method are the same as those of example 1.

Comparative example 2

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which are different from example 1 only in that modified zeolite-vermiculite is not modified, and the rest components, component contents and preparation method are the same as those of example 1.

Comparative example 3

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which are different from example 1 only in that modified chitosan is added with only potassium persulfate and urea formaldehyde, and the rest components, component contents and preparation method are the same as example 1.

Comparative example 4

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which is different from example 1 only in that composite probiotic microcapsules are not included, and the rest components, component contents and preparation method are the same as example 1.

Comparative example 5

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which is different from example 1 only in that modified zeolite-vermiculite is not included, and the rest components, component contents and preparation method are the same as those of example 1.

Comparative example 6

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which are different from example 1 only in that the modified chitosan is only carboxymethyl chitosan, and the rest components, component contents and preparation method are the same as example 1.

Comparative example 7

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which are different from example 1 only in that nano potassium humate is not included, and the rest components, component contents and preparation method are the same as those of example 1.

Comparative example 8

This comparative example provides a soil synergistic improver for saline-alkali soil and a preparation method thereof, which is different from example 1 only in that gamma-polyglutamic acid is not included, and the rest components, component contents and preparation method are the same as those of example 1.

Experimental example 1

The experimental example is used for measuring the stability of the saline-alkali soil synergistic improver in the examples and the comparative example in different pH environments, and the specific method is as follows: 2.0g of the modifier samples prepared in example 1 and comparative examples 1 to 3 were placed in test tubes, 1000mL of deionized water was added to the test tubes to adjust the pH to 5.0, 7.0 and 9.0, and the mixture was stored for 7 days, and after 7 days, the content of the modifier in the deionized water was measured to obtain the survival rate of the modifier, and the stability of the organic fertilizer to the environmental pH was analyzed.

FIG. 1 is a graph showing the results of 7 days of storage stability of the modifier prepared in example 1 and comparative examples 1-3, wherein the modifier prepared in example 1 has a survival rate of 80% or more in acidic, neutral and alkaline environments, the average survival rate of the group 1 reaches 64.2% in three pH environments, the average survival rate of the group 2 reaches 76.1% in three pH environments, and the survival rate of the group 3 is the lowest in various pH environments, and only reaches about 42.7%; the composite probiotics in the modifier prepared in the comparative example 1 are not coated by microcapsules, the stability of the composite flora is extremely poor and is easy to be influenced by surrounding environment, the composite probiotics are rapidly released in a short time, and the stability of the composite flora is reduced and the stability of the modifier is reduced without adding carboxymethyl cellulose and sodium alginate; the zeolite-vermiculite in the modifier prepared in the comparative example 2 is not modified, so that the adsorption of heavy metal ions can be reduced, and the stability of the modifier is not greatly influenced; the modified chitosan in the modifier prepared in the comparative example 3 is only added with potassium persulfate and urea formaldehyde, the urea formaldehyde is loaded in the chitosan, and as no acrylic acid solution, acrylamide and N, N' -methylene bisacrylamide are added for further modification treatment, the modified chitosan has no reticular cross-linking structure, and the mechanical strength of the modified chitosan is reduced, so that the stability of the modifier is influenced, and the survival rate of the modifier in various pH environments is greatly reduced; the modifier prepared by the embodiment of the invention has good stability in acidic, neutral and alkaline environments.

Experimental example 2

The experimental example is used for measuring the stability of the saline-alkali soil synergistic improver under different temperature and time conditions, and the specific method is as follows: 2.0g of the modifier samples prepared in examples 1-3 and comparative examples 1-8 are placed in a test tube, 100mL of deionized water is added into the test tube, the test tube is placed in an environment of-15 ℃ and 25 ℃ and 50 ℃, 7d, 30d and 180d are placed, stability performance tests at different temperatures and different times are carried out, whether material precipitation, modification agent saccule morphological damage and precipitation are caused or not is observed, the quality of the organic fertilizer is judged according to the material precipitation amount, modification agent saccule morphological damage condition and precipitation amount, the stability influence of temperature and time on the modification agent is examined, and the test results are shown in Table 1.

TABLE 1 effect of temperature and time on stability of modifier results

As shown in Table 1, the modifier prepared in the embodiment of the invention can keep good stability after 7d, 30d and 180d, and the shape of the modifier balloon is not damaged in low temperature, room temperature and high temperature environments, which indicates that the modified zeolite-vermiculite and the modified chitosan obtained by using carboxymethyl cellulose-sodium alginate as a composite flora coated by microcapsule wall materials and using octadecyl trimethyl ammonium bromide and lanthanum chloride after calcination are main factors influencing the stability of the modifier.

Experimental example 3

The experimental example is used for measuring the water absorption performance of the saline-alkali soil synergistic improver according to the examples and the comparative example, and the specific method is as follows: 1.0g of the pesticide fertilizer mixed fertilizer with uniform particle size prepared in the examples 1-3 and the comparative examples 1-4 are respectively weighed and respectively added into a 250mL beaker containing deionized water, samples are taken out at intervals to be filtered, weighed and the soil quality after water absorption is recorded, the sampling time is 0.5h, 1h, 3h, 5h, 8h, 12h, 16h and 20h, and the water absorption rate of the modifier is calculated according to the following formula:

；

Wherein, Q: water absorption (%) of the modifier; m ₁: the mass (g) of the modifier before water absorption; m ₂: quality (g) of the modifier after water absorption.

FIG. 2 is a graph showing the effect of the water absorption of the modifiers prepared in examples 1-3 and comparative examples 1-3, wherein the water absorption of the modifiers in examples 1-3 is saturated at about 20h, the water absorption is 64.7-67.9%, the water absorption is kept unchanged within 20-24h, and the water retention is good; the modifier of the comparative example 5 has saturated water absorption capacity of about 3 hours, water absorption rate of 38.5 percent, water absorption rate of 3-8 hours, and dissolution when the modifier absorbs water for about 8 hours; the modifier of the comparative example 6 has saturated water absorption capacity of about 0.5h, the water absorption rate is as high as 92.3%, and the modifier is dissolved when absorbing water for about 3 h; the modifier of the comparative example 7 has saturated water absorption capacity of about 8 hours, water absorption rate of 47.2 percent and can not be dissolved in 24 hours; the modifier of the comparative example 8 has saturated water absorption capacity of about 8 hours, water absorption rate of 55.8 percent and can not be dissolved in 24 hours; the modifier prepared in comparative example 5 does not include modified zeolite-vermiculite, has an untight internal structure, poor mechanical properties, reaches saturation after 3 hours of rapid water absorption, and is dissolved in water after 2 hours; the modified chitosan in the modifier prepared in the comparative example 6 is only carboxymethyl chitosan, and does not comprise substances capable of improving the water absorption performance of chitosan such as acrylic acid solution, acrylamide, N' -methylene bisacrylamide and the like, and the single carboxymethyl chitosan is weak in stability, and the modifier disintegrates in a short time when meeting water, so that the concentration of the modifier in a unit volume environment suddenly rises, and the adverse effect on crops is easy to occur; the modifier prepared in comparative example 7 does not include nano potassium humate, and the modifier prepared in comparative example 8 does not include gamma-polyglutamic acid, which reduces the water absorption rate of the modifier and does not affect the water retention.

Experimental example 4

The experimental example is used for measuring the nutrient release performance of the saline-alkali soil synergistic improver according to the embodiment and the comparative example, and the specific method is as follows: 1.0g of the modifier with uniform particle size prepared in the examples 1-3 and the comparative examples 3-6 is respectively weighed and put into a 60-mesh gauze bag with the size of 3cm multiplied by 3cm, 100g of air-dried soil (the moisture content is less than 3.0%) is then weighed and put into a self-sealing plastic bag, 20mL of distilled water is evenly sprayed to moisten the soil, the mouth of the bag is sealed, the bag is respectively put into an incubator with the temperature of 25 ℃ for constant temperature and static culture for 24 hours, and then the gauze bag with the modifier is buried into the soil with the pH of 7, and culture is started for 40 days; sampling 3d, 5d, 8d, 12d, 16d, 20d, 26d, 32d and 40d, drying, analyzing the nutrient content by using a soil nutrient detector, and calculating the cumulative release rate of organic matters in the culture time according to the following formula:

；

Wherein v: cumulative organic matter release rate (%), w _t: mass fraction of organic matter released amount measured in time t; w: total nutrient mass fraction of the modifier.

FIG. 3 is a graph showing the cumulative release results of organic matter nutrient for the modifiers prepared in examples 1-3 and comparative examples 3-6 according to the present invention, wherein the modifiers prepared in examples 1-3 reach nutrient release saturation in about 32 days, and the cumulative release rate of organic matter reaches 76.6-78.5%; the modifier prepared in the comparative example 3 reaches nutrient release saturation in about 12 days, and at this time, the cumulative release rate of organic matters is only 55.6%; the modifier prepared in comparative example 4 reached nutrient release saturation in about 8 days, at which time the cumulative release rate of organic matter was 69.4%; the modifier prepared in the comparative example 5 reaches nutrient release saturation in about 20 days, and at this time, the cumulative release rate of organic matters is only 64.2%; the modifier prepared in the comparative example 6 reaches nutrient release saturation in about 5 days, and at the moment, the cumulative release rate of organic matters is up to 88.2%; the modifier prepared in the embodiment 1-3 comprises composite probiotics microcapsule, modified zeolite-vermiculite and modified chitosan, carboxymethyl cellulose is used as microcapsule inner film, sodium alginate is used as microcapsule outer film, the two cooperate to protect composite flora, and enable microorganisms to be released slowly, lanthanum chloride and octadecyl trimethyl ammonium bromide are used for modifying zeolite-vermiculite, so that the zeolite-vermiculite has a porous structure, a nutrient environment for microorganism growth can be provided, growth and propagation of beneficial microorganisms in soil are promoted, urea formaldehyde is loaded into carboxymethyl chitosan super absorbent resin to obtain modified chitosan, and the components cooperate to realize the technical effect of slowly releasing modifier nutrients; the modified chitosan in the modifier prepared in the comparative example 3 is only added with potassium persulfate and urea formaldehyde, so that the water absorption and retention property cannot be improved, and the stability of the fertilizer is also reduced, so that more nutrients are released within 12 days and then the fertilizer tends to be saturated; the modifier prepared in comparative example 4 does not include composite probiotic microcapsules, and can reduce the decomposition rate of organic matters and the nutrient release rate; the modifier prepared in comparative example 5 does not include modified zeolite-vermiculite, provides little attachment sites for microorganisms, and affects nutrient release; the modified chitosan in the modifier prepared in the comparative example 6 is only carboxymethyl chitosan, and a cross-linked structure is not formed, so that the modifier releases a large amount of nutrients in a short time and reaches the saturation point of nutrient release quickly.

Experimental example 5

Test treatment: selecting a certain corn planting test field in the sun-shine city of Shandong province, dividing the corn planting test field into 9 small blocks/mu with the same area, randomly arranging the corn planting test field, spacing between each small test field by 0.5m, respectively scattering the soil conditioner mixed common fertilizer prepared in the examples 1-3 and the comparative examples 1-8 into the test field when corn grows to 20-30cm in the beginning of 8 months, wherein the scattering amount is 40 kg/mu, the weight ratio of the soil conditioner to the common fertilizer is 3:1, taking clear water as a blank control group, measuring each physical and chemical property of the soil after 45 days, selecting 1500 corn plants per mu, and counting the total yield, average plant height, thousand grain weight, withering rate, insect pest rate and nutrient content of each mu.

The soil performance measurement method used in the experimental example comprises the following steps:

1. heavy metal pollutants of lead, chromium, mercury, zinc and copper in soil: atomic absorption spectrometry;

2. organic matter, soil porosity, soil volume weight: the method is a potassium dichromate capacity method, a water level gauge method and a cutting ring method respectively;

3. soil total nitrogen, quick-acting phosphorus and quick-acting potassium: respectively a semi-trace Kai method, a photoelectric colorimetry and a flame photometry method;

4. Soil urease, phosphatase, catalase, total salt amount respectively: respectively an indophenol colorimetric method, a disodium phosphate colorimetric method, a phenol oxidation method and a conductive method.

Table 2 results of measuring various physical and chemical properties of soil

As can be seen from Table 2, the synergistic effect among the components of the synergistic improver for the saline-alkali soil prepared by the embodiment of the invention can improve the removal rate of heavy metal pollutants, increase the content of organic matters in soil, improve the porosity of the soil, reduce the volume weight of the soil, be beneficial to improving the quality of the soil, loosen the soil, reduce the hardening condition of the soil, improve the total nitrogen, quick-acting phosphorus, quick-acting potassium, urease, phosphatase and catalase, improve the soil environment and be beneficial to improving the growth of crops in the soil and increasing the yield of the crops in the soil, and the soil improver can effectively restore the saline-alkali soil, keep the soil neutral and also reduce the total salt content of the soil.

TABLE 3 corn growth performance measurement results

As can be seen from Table 3, the modifier prepared by the embodiment of the invention realizes the slow release of the modifier by adding the modified zeolite-vermiculite and the modified chitosan, achieves the technical effect of long-term fertilizer conservation, ensures that the utilization rate of the modifier is higher, the crop seeds are plump, and the composite probiotic microcapsules are added to effectively improve the stability of the microbial agent, improve the soil ventilation condition and improve the air permeability of the soil, and the modifier has synergistic effect with nano potassium humate and gamma-polyglutamic acid to strengthen the immunity of plants and improve the resistance of the plants to pathogenic microorganisms, thereby reducing the harm of pathogenic bacteria to the plants and enhancing the immunity and disease resistance of crops.

Fig. 4 is a graph showing the effect of the improvers prepared in the examples 1 and the comparative examples 1-8 on the nutritional quality of corn, and as shown in the graph, the starch contents of the examples 1 and the comparative examples 2,3, 5, 7 and 8 have very significant differences compared with the blank control group, the starch contents of the comparative examples 1, 4 and 6 have significant differences compared with the blank control group, the starch content of the comparative example 6 has no significant differences compared with the examples 1 and the comparative examples 1-5 and 7-8, and the starch contents of the comparative examples 1 and 4 have significant differences compared with the examples 1 and the comparative examples 1-5 and 7-8, so that the improvers prepared in the examples not only can improve the yield of crops, but also can improve the nutritional quality of crops and have positive effects on the improvement of the nutritional ingredients of crops.

Experimental example 6

In this experimental example, the modified chitosan prepared in example 1 was scanned by an electron microscope, and fig. 5 is a scanning image of the modified chitosan prepared in example 1 of the present invention with 500 times magnification of the electron microscope.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

The invention and its embodiments have been described above with no limitation, and the invention is illustrated in the figures of the accompanying drawings as one of its embodiments, without limitation in practice. In summary, those skilled in the art, having benefit of this disclosure, will appreciate that the invention can be practiced without the specific details disclosed herein.

Claims

1. The utility model provides a soil synergism modifier for saline and alkaline land which characterized in that: the modifier comprises the following components in parts by weight: 100-150 parts of wormcast fermentation liquor, 8-10 parts of composite probiotics microcapsule, 50-80 parts of modified zeolite-vermiculite, 10-20 parts of modified chitosan, 3-5 parts of amino acid, 3-5 parts of vitamin, 5-7 parts of biological glycolipid, 1-2 parts of nitrification inhibitor, 10-15 parts of nano potassium humate, 10-15 parts of calcium superphosphate and 1-2 parts of gamma-polyglutamic acid;

The wormcast fermentation liquid is obtained by mixing and fermenting wormcast and an activated microbial agent, and filtering and removing impurities;

The composite probiotic microcapsule comprises a microcapsule core material and a wall material; the core material comprises an activated composite flora coated by soybean oil; the wall material comprises a carboxymethyl cellulose and sodium alginate composite film;

the modified zeolite-vermiculite is obtained by crushing, mixing and calcining zeolite and vermiculite, and modifying by octadecyl trimethyl ammonium bromide and lanthanum chloride;

The modified chitosan is obtained by loading urea formaldehyde into carboxymethyl chitosan super absorbent resin.

2. The synergistic modifying agent for saline-alkali soil according to claim 1, wherein:

the amino acid is at least one selected from lysine, methionine, threonine, tryptophan and glycine;

The vitamin is at least one selected from vitamin A, vitamin C, vitamin E, vitamin B1 and vitamin B3;

The biological glycolipid is at least one selected from rhamnolipid, xylolipid, sophorolipid and trehalose lipid;

The nitrification inhibitor is selected from at least one of 4-dimethylaminopyridine, 3, 4-dimethylpyrazole phosphate, dicyandiamide and 2-chloro-6- (trichloromethyl) pyridine.

3. The synergistic modifying agent for saline-alkali soil according to claim 2, wherein: the preparation method of the wormcast fermentation liquid specifically comprises the following steps:

The mass fraction of the calcium chloride aqueous solution is 2-3%;

The addition amount of the activated composite flora is 3-5% of the weight of the wormcast.

4. A synergistic modifying agent for saline-alkali soil as claimed in claim 3, wherein: the preparation method of the activated composite flora specifically comprises the following steps:

The viable count of the klebsiella oxytoca is more than 1.2 multiplied by 10 ⁷ CFU/g; the number of the bacillus bailii viable bacteria is more than 2.0X10 ⁸ CFU/g.

5. The synergistic modifying agent for the saline-alkali soil according to claim 4, wherein: the preparation method of the modified zeolite-vermiculite specifically comprises the following steps:

The volume ratio of the lanthanum chloride solution to the octadecyl trimethyl ammonium bromide solution is 1:3-5;

the solid-liquid ratio of the zeolite, the vermiculite and the mixed solution is 1:1:40-50.

6. The synergistic modifying agent for the saline-alkali soil according to claim 5, wherein: the preparation method of the modified chitosan specifically comprises the following steps:

In step ①, the mass ratio of urea to formaldehyde solution is 1:1.5-2;

In the step ②, the mass-volume ratio of the chitosan to the isopropanol is 10-12g:200mL;

In the step ③, the mass ratio of the chitosan, the potassium persulfate, the urea formaldehyde, the acrylamide and the N, N' -methylenebisacrylamide is 10-20:0.5-0.7:20-30:1-2:3-5;

the mass volume ratio of the carboxymethyl chitosan to the acrylic acid solution is 10-20g to 100mL;

the mass concentration of the acrylic acid solution is 85%.

7. A method for preparing the synergistic modifying agent for the saline-alkali soil according to any one of claims 1 to 6, which is characterized in that: the method specifically comprises the following steps:

S1, dispersing activated composite flora in soybean oil, filtering and drying to obtain a composite probiotic microcapsule core material; dissolving carboxymethyl cellulose in 20mL deionized water, homogenizing for 10-15min at 10000r/min, adding composite probiotic microcapsule core material, and mixing to obtain composite solution; dissolving sodium alginate in 30mL deionized water, homogenizing at 10000r/min for 10-15min, adding into the composite liquid, and spray drying to obtain composite probiotic microcapsule;

in the step S1, the mass ratio of the complex bacterial group to the carboxymethyl cellulose to the sodium alginate is 8-10:1-3:2-3;

The spray drying conditions are as follows: the air inlet temperature is 160-180 ℃, the air outlet temperature is 80-90 ℃ and the flow rate is 15-20mL/min;

In the step S2, the steam curing is to put the materials into a steam curing box with the temperature of 80-100 ℃ and the relative humidity of 60-70%, heat up to 90-110 ℃ at the speed of 15-25 ℃/h, steam cure for 5-7h;

in the step S3, the mass ratio of the modified chitosan to glutaraldehyde is 10-20:0.1.