1. An alkaline soil remediation microbial inoculum is characterized in that: the effective viable count (cfu) of the alkaline soil remediation microbial inoculum is more than or equal to 5.0 hundred million/g, the rate of mixed bacteria is less than or equal to 20 percent, CaO is more than or equal to 10 percent, and S is more than or equal to 8.0 percent.

2. The alkaline soil remediation microbial inoculum of claim 1, wherein: the alkaline soil remediation microbial inoculum comprises the following components in parts by weight: 0.3-0.9 part of bacillus subtilis, 0.5-1.2 parts of brevibacillus laterosporus, 0.4-1.5 parts of trichoderma harzianum, 5-15 parts of wheat bran powder, 0.5-10 parts of sulfur and 9-10 parts of activated humic acid.

3. The alkaline soil remediation microbial inoculum of claim 2, wherein: the alkaline soil remediation microbial inoculum also comprises the following components in parts by weight: 15-18 parts of phosphogypsum and 5-15 parts of light calcium carbonate.

4. A method for preparing an alkaline soil remediation microbial inoculum according to any one of claims 1 to 3, which comprises the steps of: the method comprises the following steps:

s1, uniformly mixing the activated humic acid and the wheat bran powder, adding bacillus subtilis, bacillus laterosporus and trichoderma harzianum, and fermenting for 3-8 days at the temperature of 30-45 ℃ to obtain a fermentation mixture;

s2, adding phosphogypsum, sulfur and light calcium carbonate into the fermentation mixture;

s3, preparing powder or granules and drying.

5. The method of claim 4, wherein: the phosphogypsum is pretreated, and the method comprises the following steps: introducing 200-250 ℃ hot air into the phosphogypsum with the water content of 18-30% in a rotary kiln for drying, and in the drying process, a crushing mechanism is arranged in the rotary kiln for crushing the phosphogypsum into phosphogypsum powder.

6. The method of claim 4, wherein: and 4-5 parts by weight of soy sauce residues are also added in the step S1.

7. The method of claim 6, wherein: 8-12 parts by weight of orange vinegar residue is also added in the step S1.

8. The method of claim 4, wherein: in step S2, 5-15 parts by weight of expandable graphite is added.

9. The method of claim 8, wherein: in step S2, 3-5 parts by weight of diatomaceous earth is added.

Background

Saline soil, or saline-alkali soil, in the agricultural field, soil with a soluble salt content of more than 2% can be defined as saline soil, and the growth of crops can be adversely affected by the content of the soluble salt. The distribution range of the saline soil in China is wide, the area is large, and the saline soil tends to be further expanded. The main areas of distribution are arid, semi-arid inland areas and coastal areas. The salinization problem restricts the sustainable development of arid regions and the improvement of the environmental quality. In recent years, various methods for improving and optimizing saline-alkali soil are developed, including: 1) hydraulic engineering improvement reaches the effect of proper irrigation and timely drainage to reduce the salt content of soil, but the cost is higher, consumes manpower and materials. 2) Mulching a mulching film or mulching straw scales and other farmland products to reduce the contact between soil and air and reduce water evaporation so as to achieve the effect of water retention, but the method influences the balance of microbial flora in the soil due to the fact that the soil is covered with the method. 3) The addition of chemical modifiers such as gypsum, calcium superphosphate, aluminium sulphate is improved by the principle of acid-base neutralization, but pure chemical modification has the risk of environmental pollution. The soil fertility is not increased by the improvement method, and the improvement time is not long enough. In addition, while improving the soil, attention is paid to improving the soil fertility and prolonging the soil improvement time.

Disclosure of Invention

In order to solve the technical problems, the invention provides an alkaline soil remediation microbial inoculum and a preparation method thereof.

The scheme of the invention is as follows:

an alkaline soil remediation microbial inoculum, wherein the effective viable count (cfu) of the alkaline soil remediation microbial inoculum is more than or equal to 5.0 hundred million/g, the rate of mixed bacteria is less than or equal to 20 percent, CaO is more than or equal to 10 percent, and S is more than or equal to 8.0 percent.

Preferably, the alkaline soil remediation microbial inoculum comprises the following components in parts by weight: 0.3-0.9 part of bacillus subtilis, 0.5-1.2 parts of brevibacillus laterosporus, 0.4-1.5 parts of trichoderma harzianum, 5-15 parts of wheat bran powder, 0.5-10 parts of sulfur and 9-10 parts of activated humic acid.

Further preferably, the alkaline soil remediation microbial inoculum also comprises the following components in parts by weight: 15-18 parts of phosphogypsum and 5-15 parts of light calcium carbonate.

The preparation method of the alkaline soil remediation microbial inoculum comprises the following steps:

s1, uniformly mixing the activated humic acid and the wheat bran powder, adding bacillus subtilis, bacillus laterosporus and trichoderma harzianum, and fermenting for 3-8 days at the temperature of 30-45 ℃ to obtain a fermentation mixture;

s2, adding phosphogypsum, sulfur and light calcium carbonate into the fermentation mixture;

s3, preparing powder or granules and drying.

Preferably, phosphogypsum is pretreated by the following method: introducing 200-250 ℃ hot air into the phosphogypsum with the water content of 18-30% in a rotary kiln for drying, and in the drying process, a crushing mechanism is arranged in the rotary kiln for crushing the phosphogypsum into phosphogypsum powder.

Preferably, 4-5 parts by weight of soy sauce residues are also added in the step S1.

Further preferably, 8-12 parts by weight of the orange vinegar residue is also added in the step S1.

Preferably, 5 to 15 parts by weight of expandable graphite is further added in step S2.

Further preferably, 3 to 5 parts by weight of diatomaceous earth is also added in step S2.

The invention has the beneficial effects that:

1. the four-season positioning test shows that the soil microbial remediation microbial inoculum has an obvious effect on improving saline-alkali soil and an obvious effect on increasing the yield of wheat and corn.

1) The volume weight of the saline-alkali soil can be obviously reduced by additionally applying the soil microorganism remediation microbial inoculum. Through a four-season test, the volume weight of the soil treated by the microbial remediation microbial inoculum for K3 is reduced from 1.24g/cm3 to 1.10g/cm3, and is reduced by 11.29% on average compared with a control K0. The volume weight of the K2 soil treated by the applied inactivated microbial inoculum is reduced by 8.06 percent compared with that of the contrast K0. The microbial remediation microbial inoculum is applied to loosen soil and enhance permeability, and provides good soil conditions for the root system of crops to absorb nutrients and water. Lays a foundation for increasing the yield of wheat and corn. The K3 and K2 achieve obvious difference, which shows that the soil microorganism remediation microbial inoculum improves volume weight, and the effect of microorganisms cannot be ignored.

2) The pH value of saline-alkali soil is obviously reduced by using the soil microorganism repairing microbial inoculum, the pH value is reduced from 8.55 of an initial soil sample to 8.33, the pH value is reduced by 1.17% from K0 in the first season to 2.57% from K0 in the fourth season, although the reduction range is not large, the pH value of the soil is continuously improved along with the increase of the service life. The inactivated soil remediation agent also has a certain reduction in soil pH, but its improvement does not increase significantly with age.

3) The soil microorganism repairing microbial inoculum has obvious promotion effect on the formation of different components of soil aggregates larger than 0.25mm, except that the increasing rate of 0.5-1mm particle size is 5.36 percent compared with K0, the increasing rate of other particle sizes is more than 20 percent compared with K0, wherein the component larger than 5mm is 33.51 percent compared with K0. The active microorganisms contained in the soil micro-aggregate particularly improve the content of the soil micro-aggregates with large particle size. The improvement of soil aggregates also plays an important role in improving the content of microorganisms in soil, and the two promote each other.

4) The total microbial load was significantly increased by the application of the microbial remediation inoculum over the control K0. The main expression is that the number of bacteria and actinomycetes is increased compared with K0, and the number of fungi is slightly reduced. Compared with K0, the K3 treated actinomycetes amount is increased by 75.4%, the bacteria amount is increased by 114.86%, the fungus amount is increased by-18.75%, and the total microorganism amount is increased by 107.28%. The effect of the microbial repairing microbial inoculum is greater than the effect of the inactivation matrix. The B/F ratio of bacteria/fungi is an important indicator of the structure that reflects the microbial population of the soil. The B/F value of the treatment of applying the soil microbial remediation microbial inoculum reaches 65.38, which is 1.64 times of that of farmer habit K0.

5) The yield (wheat) of the soil microorganism repairing microbial inoculum treated K3 reaches 406.42kg in the first season, the yield is increased by 6.75 percent compared with that of the inactivated soil microorganism repairing microbial inoculum K2, and the yield is increased by 16.49 percent compared with that of farmer habit treated K0; the yield of K3 in the second season (corn) is 495.93kg, which is increased by 10.72 percent compared with K2 and 18.45 percent compared with K0; the yield of K3 in the third season (wheat) is 439.80kg, which is increased by 8.19% compared with K2 and 25.23% compared with K0; the yield of the corn in the fourth season (corn) K3 is 512.33kg, the yield is increased by 12.05 percent compared with that of K2, the yield is increased by 19.29 percent compared with that of the treatment by farmers, and the difference is obvious. With the application of the remediation microbial inoculum, the physical and chemical properties of the soil are improved, and the yield of wheat and corn is greatly improved compared with the habit of farmers. The yield and the cost investment of the wheat and the corn are increased by applying the soil microbial remediation microbial inoculum additionally, and the pure income increase of the soil microbial remediation microbial inoculum is respectively 67.95 yuan, 90.75 yuan, 148.76 yuan and 104.69 yuan compared with the habit of farmers in the four seasons by the comprehensive calculation. Meanwhile, the microbial remediation microbial inoculum has an improvement function on indexes such as the volume weight, the pH value, soil aggregates, soil microorganisms and the like of saline-alkali soil, and the product has a great application prospect in the aspects of improving the soil and improving the soil fertility.

2. The soy sauce residue is rich in protein, starch, fat and other nutrient components, the invention utilizes the high organic matter content of the soy sauce residue to make up the defect of insufficient organic matter content of soil, and the organic matter content can be increased to 15-35 g/kg. However, the soy sauce residues are very high in viscosity and very high in oil content, and are often bonded into blocks when being used for fermenting with activated humic acid and wheat bran powder, and cannot be fermented uniformly, so that the citrus vinegar residues are also added in the invention, are leftovers of fruits processed in the process of preparing citrus vinegar from citrus, mainly comprise peels, tangerine pith, residual pulp and the like, and mainly comprise pectin and dietary fiber, which account for about 40-50% of the fruits. Meanwhile, the pH value of the citrus vinegar residues is low, and alkaline substances in alkaline soil can be neutralized.

3. The invention utilizes the micro-expansion characteristic of the phosphogypsum to lead the phosphogypsum to form a framework of the repairing agent in the final finished product repairing agent, the fermentation mixture forms a network derived by taking the framework as a base point, and the light calcium carbonate and the sulfur are filled on the network framework to improve the soil. And because the adsorbability of the expanded graphite can also absorb the salt in the soy sauce, the adverse effect of the salt in the soy sauce is eliminated, and the phosphogypsum, the light calcium carbonate, the sulfur and the expanded graphite are uniformly dispersed in a plurality of sites and used for absorbing alkaline ions in saline-alkali soil.

4. At the in-process of adding graphite, expanded graphite and calcium carbonate can appear and can precipitate in the bottom, unable stirring, the inhomogeneous phenomenon of repairing agent layering appears, and this application adds diatomaceous earth at the compounding in-process, plays the effect of solid-state suspension to expanded graphite, guarantees the homogeneity of microbial inoculum quality.

5. The phosphogypsum is solid waste residue generated when phosphorite is treated by sulfuric acid in the production of phosphoric acid, the main component of the phosphogypsum is calcium sulfate, the phosphogypsum can neutralize the acid-base property of soil, and the phosphogypsum is crushed to release F ions and phosphorus ions in crystal lattices, so that the damage to plants caused by entering the soil is reduced.

Detailed Description

The invention is further illustrated by the following examples, but the scope of the invention as claimed is not limited to the scope of the examples.

The technical index and the harmless index requirements of the repairing agent of the invention are shown in the table A-B.

TABLE A technical indexes of repair microbial inoculum products

TABLE B harmlessness index requirement

Example 1

An alkaline soil remediation microbial inoculum, wherein the effective viable count (cfu) of the alkaline soil remediation microbial inoculum is more than or equal to 5.0 hundred million/g, the rate of mixed bacteria is less than or equal to 20 percent, CaO is more than or equal to 10 percent, and S is more than or equal to 8.0 percent.

Preferably, the alkaline soil remediation microbial inoculum comprises the following components in parts by weight: 0.5 part of bacillus subtilis, 0.8 part of bacillus laterosporus, 0.9 part of trichoderma harzianum, 10 parts of wheat bran powder, 9 parts of sulfur and 9 parts of activated humic acid.

Further preferably, the alkaline soil remediation microbial inoculum also comprises the following components in parts by weight: 12 parts of phosphogypsum and 10 parts of light calcium carbonate.

The preparation method of the alkaline soil remediation microbial inoculum comprises the following steps:

s1, uniformly mixing the activated humic acid and the wheat bran powder, adding bacillus subtilis, bacillus laterosporus and trichoderma harzianum, and fermenting for 5d at 38 ℃ to obtain a fermentation mixture;

s2, adding phosphogypsum, sulfur and light calcium carbonate into the fermentation mixture;

s3, preparing powder or granules and drying.

The field test reports:

1. test site and basic conditions

The mountains and east provinces at the yellow river farm land are beneficial to the reclamation of the eastern provinces, belong to continental climate in the northwest temperate east Asia monsoon region, have an average annual temperature of about 12 ℃, and have a test land soil type of moisture soil. The test design is a positioning test of wheat-corn-wheat-corn crop rotation, the test year is 2017-2019, 0-20cm of soil is collected before the test is started to serve as a foundation soil sample, and the basic physicochemical properties of the soil are measured after the soil is naturally air-dried (see table 1). The tested crops are corn and winter wheat, and the design of completely random block groups is adopted, each treatment is repeated for 3 times, and the area of each cell is 50m²(5mxl0m), the total land occupation is 1.2 mu.

The fertilizing method comprises the following steps: 50% of nitrogen fertilizer, 100% of phosphorus-potassium fertilizer and a tested product are applied before soil preparation in wheat season, mechanical sowing is carried out when soil picking conditions are proper, and 50% of nitrogen fertilizer is applied after wheat is pulled out in the second year; in corn season, 40% of nitrogen fertilizer, 100% of phosphorus-potassium fertilizer and a test product are used as base fertilizers to be applied outside a sowing row with 10 male ditches, and the residual 60% of nitrogen fertilizer (urea) is applied in a topdressing mode in a large-horn-mouth period. The fertilizer consumption and the fertilizer application method of each district are consistent in three years. The farmland management such as irrigation, disease, pest and grass control and the like is normally carried out according to the habit of farmers.

TABLE 1 test plot soil conditions

2. The test variety and the cultivation mode are that the corn variety is Tianta 119, and the winter wheat variety is Qingmai No. 6.

3. Test method

3.1 test design

4 treatments are set, the three times of treatment are repeated, the area of a cell is 50m2, the cell is randomly arranged, and a protection row is set for the cell for 2 meters. The specific treatment is as follows:

k0, conventional fertilization;

k1 processing, namely optimizing fertilization;

treatment K2, optimized fertilization + inactivation of the soil microbial remediation inoculum (made in example 1) (60 kg/mu);

treatment K3 optimized fertilization + soil microbial remediation inoculum (made in example 1) (60 kg/acre).

Treatment K4: optimized fertilization plus soil microbial remediation inoculum (made in example 2) (60 kg/acre).

Treatment K5: optimized fertilization plus soil microbial remediation inoculum (made in example 3) (60 kg/acre).

Treatment K6: optimized fertilization plus soil microbial remediation inoculum (made in example 4) (60 kg/acre).

Treatment K7: optimized fertilization plus soil microbial remediation inoculum (made in example 5) (60 kg/acre).

3.2 fertilizing method

(1) The K0 is treated to be used by farmers for fertilizer application, 50 kilograms of diammonium is applied per mu in wheat seasons (9 kilograms of pure nitrogen and 23 kilograms of phosphorus), the fertilizer is spread and ploughed, and 15.2 kilograms of urea is applied in topdressing (7 kilograms of pure nitrogen). The corn season fertilization is to apply 50 kg of compound fertilizer (7.5 kg of pure nitrogen, 7.5 kg of phosphorus and 7.5 kg of potassium) per mu, and the fertilizer is spread and ploughed. 10 kg of urea (4.6 kg of pure nitrogen) is applied.

(2) The K1 treatment is optimized fertilization, 15.2 kg of urea, 28.89 kg of heavy calcium and 8 kg of potassium sulfate (7 kg of pure nitrogen, 13 kg of phosphorus and 4 kg of potassium) are applied to each mu of wheat season base fertilizer for broadcasting and turning over. 15.2 kg of urea (7 kg of pure nitrogen) is applied. 13 kilograms of urea, 43.75 kilograms of calcium superphosphate, 12 kilograms of potassium sulfate (6 kilograms of pure nitrogen, 7 kilograms of phosphorus and 6 kilograms of potassium) are applied to each acre of corn in a season, and fertilizers are spread for ploughing. 5 kg of urea is applied.

(3) Treatment K2 on the basis of optimizing fertilization, 60 kg/mu of high-temperature and high-pressure inactivated soil microorganism remediation microbial inoculum (prepared in example 1) is basal applied and is spread together with fertilizers for ploughing.

(4) Treatment K3 on the basis of optimizing fertilization, 60 kg/mu of soil microbial remediation fungicide (prepared in example 1) is basal applied and is spread together with fertilizer for ploughing.

(5) Treatment K4: the optimized fertilization plus the soil microorganism remediation microbial inoculum (prepared in example 2) (60 kg/mu) are applied together with fertilizers for ploughing.

(6) Treatment K5: the optimized fertilization plus the soil microorganism remediation microbial inoculum (prepared in example 3) (60 kg/mu) are applied together with fertilizers for ploughing.

(7) Treatment K6: the optimized fertilization plus the soil microorganism remediation microbial inoculum (prepared in example 4) (60 kg/mu) are applied together with fertilizers for ploughing.

(8) Treatment K7: the optimized fertilization plus the soil microorganism remediation microbial inoculum (prepared in example 5) (60 kg/mu) are applied together with fertilizers for ploughing.

3.3 field management and planting time

In the first season winter wheat test, fertilizing, ploughing and sowing are carried out in 5 days of 10 months in 2017, and harvesting is carried out in 6 last days of 2018; in the second-season corn test, fertilizing and sowing in 2018, 6 and 16 months, and harvesting in the first 10 months; in the third season, winter wheat is tested, fertilization, ploughing and sowing are carried out on 12 days in 10 months in 2019, and harvesting is carried out on 6 th-last days in 2019; the summer corn test in the fourth season comprises fertilizing, ploughing and sowing in 20 days 6 and 6 months in 2019, and harvesting in 10 days last in 2019. The seeding density of the corn is 4100 plants/mu, and the seeding quantity of the wheat per mu is 20 kilograms; and in each season, the seeds are independently harvested, weighed and counted according to the residential area, and other cultivation management measures are consistent with the habits of local farmers.

3.4 sample Collection and measurement

Soil sample determination after crops are harvested in each season, sampling 5 points in a plum blossom shape in each cell, taking soil from 0-20cm of the ground surface by a cutting ring, and determining the volume weight of the soil; after summer corns are harvested in the fourth season, undisturbed soil of 20 multiplied by 20cm test land is taken back to a laboratory for measurement, the pH value of the soil is measured by a pH meter, the volume weight of the soil is measured by a ring cutter method, soil aggregates are measured by a wet sieve method, and other basic physical and chemical properties of the soil are analyzed by referring to a related method of soil agricultural chemical analysis method in literature. Statistical data analysis was performed using Excel2010 and DPS v7.05 statistical software.

4 results and analysis

4.1 Effect of soil microbial remediation Agents on soil bulk density

The soil volume weight is one of important physical properties of soil, the soil with a good structure has small volume weight and good porosity, and is beneficial to the regulation of water, fertilizer, gas and heat conditions of the soil and the activity of plant roots. From the test results of four seasons (table 2), the soil volume weight of the test area is gradually reduced along with the increasing application of the soil microbial remediation microbial inoculum, and the difference of the soil volume weight among different treatments reaches the significance level of 5%. From the change trend, the treatments K2 and K3 added with the remediation microbial inoculum both have the effect of obviously reducing the volume weight of the soil. After the harvest in the first season, the unit weight of the optimized fertilization K1 is reduced by 1.22% compared with that of the farmer habit K0, and the unit weights of the treatments K2 and K3 are reduced by 4.88% and 6.5% compared with that of the treatment K0 respectively, wherein the difference between the treatment K3 and the treatment K2 is obvious. The volume weight change of the soil in the second, third and fourth seasons has similar regularity. With the continuous application of the remediation microbial inoculum every season, the gap between the soil unit weight of K2 and K3 and the soil unit weight of farmer habit K0 continues to increase. After harvesting in the fourth season, the bulk weight of the treated K2 is 1.14g/cm3, the bulk weight of the treated K3 is 1.10g/cm3, and the bulk weight is respectively reduced by 8.06% and 11.29% compared with the weight of the farmer habit K0. The bulk weight of treatment K3 was reduced by 3.23% over treatment K2 to a significant level of difference. The effect of the microbial strains in the remediation microbial inoculum on the volume weight of the soil is not ignored.

TABLE 2 Effect of different treatments on soil bulk weight

The concentration of the active ingredient is maintained between 0.35% and 0.70%. The pH of the soil treated with K3 tended to decrease continuously and to increase continuously with time away from K0. After harvest in the first season, the pH values of the treatments K2 and K3 are respectively reduced by 0.7 percent and 1.17 percent compared with K0; in the second season, the pH values of the treatments K2 and K3 are reduced by 1.17 percent and 1.75 percent respectively compared with the pH value of K0; in the third season, the pH values of the treatments K2 and K3 are reduced by 1.17 percent and 1.87 percent respectively compared with the pH value of K0; after harvesting in the fourth season, the pH values of treatments K2 and K3 were reduced by 1.40% and 2.57% respectively compared to K0. Treatments K2 and K3 achieved a significant level of 5% difference from treatment K0. A significant level of 5% difference was also achieved between treatments K2 and K3.

The four-season test data are integrated, the soil microorganism remediation microbial inoculum is used, the pH value of the soil is obviously reduced, although the reduction range is small, from 1.17% in the first season to 2.57% in the fourth season, the pH value of the soil is continuously improved along with the increase of the service life. The inactivated soil remediation microbial inoculum also has a certain reduction effect on the pH of the soil, but the improvement effect of the soil remediation microbial inoculum is not obviously increased along with the increase of the application age.

TABLE 3 Effect of different treatments on soil pH

4.3 Effect of different treatments on soil aggregate content

The soil aggregate is a good soil structure body and plays an important role in regulating water, gas and temperature of soil. In saline alkali soil, a low content of soil aggregates larger than 0.25mm is a major factor affecting plant growth.

After the remediation microbial inoculum is applied, aggregates larger than 0.25mm in the saline-alkali soil tend to increase. The processing K3 is obviously improved compared with the habit of farmers K0 and the optimized fertilization K1 in several grain sizes of 0.25-0.5mm, 0.5-1mm, 1-2mm, 2-5mm and more than 5mm, and the obvious difference is achieved. K3 has different promoting effects on aggregates with different particle sizes in soil. Compared with K0, the content of 0.25-0.5mm aggregates treated by K3 is increased by 24.41%, the content of 0.5-1mm is increased by 5.36%, the content of 1-2mm is increased by 24.69%, the content of 2-5mm is increased by 28.86%, and the content of >5mm particle size is increased by 33.51%. The effect of the remediation microbial inoculum on promoting the soil large-particle-size aggregates is more obvious. Compared with K2, the treated K3 has a particle size of 0.5-lmm, the soil aggregate K3 with other particle sizes is remarkably different from that of K2, particularly the particle size of more than 0.5mm is increased by 21.79% compared with that of K2 by K3.

The application effect of the inactivated soil microorganism repairing microbial inoculum (treatment K2) on the formation of soil aggregates is better than that of farmer habit treatment (K0) and optimized fertilization treatment (K1), but the application effect of the inactivated soil microorganism repairing microbial inoculum (treatment K3) is not far reached, and the difference is significant. In general, the application of the soil microorganism repairing microbial inoculum has a remarkable promoting effect on the formation of soil aggregates, and the contained active microorganisms particularly improve the content of soil micro-aggregates with large particle size (>5 mm).

TABLE 4 Effect of different treatments on particle size grading of soil Water-stable agglomerates (%)

4.4 Effect of different treatments on the number of microbial populations in the soil

After the fourth harvest, the number of fungi, actinomycetes and bacteria in the soil layers of 0-30cm each of the treatments was determined (Table 5). Different treatments have a significant impact on soil microbial counts. The total number of microorganisms, actinomycetes and bacteria of the treatment K3 with the soil microorganism repairing microbial inoculum is obviously increased compared with other treatments. The number of fungi did not differ much between treatments. Compared with the farmer habit K0, the number of actinomycetes treated by the K3 is increased by 75.4%, the number of bacteria is increased by 114.86%, the number of fungi is increased by-18.75%, and the total amount of microorganisms is increased by 107.28%. Compared with K0, the K2 treatment has the advantages of increasing the number of actinomycetes by 45.63%, the number of bacteria by 33.59%, the number of fungi by-6.25% and the total number of microorganisms by 32.99%. It can be seen that the number of bacteria is increased by 60.83%, the number of actinomycetes is increased by 20.44%, the number of fungi is increased by-13.33%, and the total microbial quantity is increased by 55.85% based on K2 in K3. The effect of the microbial repairing microbial inoculum is far greater than the effect of the inactivation matrix. The ratio B/F of bacteria/fungi may reflect the structure of the soil microbial population, and it is generally believed that the greater this ratio, the more fertile the soil. The B/F value of saline-alkali soil is generally lower than that of conventional field soil and vegetable field soil. In the test, the B/F value of the treatment by applying the soil microbial remediation agent reaches 65.38, and the B/F values of K0, K1 and K2 are 24.73, 31.12 and 35.23 respectively. The B/F value of the treatment K3 is 1.64 times that of the farmer's habit K0. The application of the microbial remediation microbial inoculum can improve the total microbial quantity of the soil and optimize the microbial colony structure.

TABLE 5 Effect of different treatments on the number of microbial populations in the soil

4.5 Effect of different treatments on crop yield

The yield results showed significant differences in the yields of the different treatments (table 6). In general, the optimization of the fertilization treatment K1 resulted in a definite increase in crop yield but in a limited proportion, as demonstrated in the four season trials. The yield of the repairing microbial inoculum K3 and the inactivating repairing microbial inoculum K2 is greatly improved compared with the optimized fertilization K1. The yield improvement range of the treated K3 is obviously higher than that of the K2 treated by the inactivated fungicide. The yield of wheat and corn in four seasons is highest when the soil microbial remediation microbial inoculum is applied for treatment K3. The first, second, third and fourth season treatments increase the K3 yield by 16.49% respectively compared with the K0; 18.45 percent; 25.23% and 19.29%. Compared with the treatment K2 using the inactivated soil microorganism repairing microbial inoculum, the yield is increased by 6.75 percent respectively; 10.72 percent; 8.19% and 12.05%. The yield increasing effect is better than that of the K2 treatment, and the difference is obvious.

TABLE 6 Effect of different treatments on crop yield

5 test economic benefit analysis

The economic benefits of different treatments in the four-season test are compared, other agronomic measures are the same, and only the input and output of the applied fertilizer and the soil microorganism remediation microbial inoculum are calculated. The input-output ratio is calculated according to the prices of 2000 yuan/t of soil microbial remediation microbial inoculum, 2000 yuan/t of urea, 3000 yuan/t of 45% compound fertilizer, 900 yuan/t of calcium superphosphate (16%), 2800 yuan/t of diammonium, 3500 yuan/t of potassium sulfate, 1600 yuan/t of heavy calcium, 2.5 yuan/kg of corn and 2.6 yuan/kg of wheat, and the results are shown in tables 7, 8, 9 and 10.

As can be seen from Table 7, the wheat is planted in the saline-alkali soil of the first season, and the income increase of 149.55 yuan per mu is higher than that of K0 mu treated by farmers by applying the soil microbial remediation fungicide K3, so that the cost is increased and the income increase of 67.95 yuan per mu is high due to the addition of the soil microbial remediation fungicide; compared with K2, the cost investment of K3 is the same, K3 is increased by the action of microorganisms compared with K2, and the pure income per mu is increased by 61.18 yuan.

TABLE 7.2018 analysis table of wheat benefit

The soil microbial remediation microbial inoculum is 2.00 yuan kg (sold in the market), and the wheat price is 2.6 yuan kg in 2018.

As can be seen from Table 8, when corns are planted in the saline-alkali soil of the second season, the income is increased by 193.13 yuan per mu when K3 is processed compared with K0 mu which is used by farmers for fertilizing, and the pure income per mu is increased by 90.75 yuan due to the increased cost of the microbial remediation fungicide applied to the soil; compared with the treatment K2, the treatment K3 has consistent cost investment, and the treatment K3 increases the effect of microorganisms compared with the treatment K2, so that the pure income per mu is increased by 112.23 yuan.

TABLE 8.2018 analysis chart of maize profit situation

The soil microbial remediation microbial inoculum is 2.00 yuan kg (sold in the market), and the price of the corn in 2018 is 2.5 yuan kg.

As can be seen from Table 9, wheat is planted on the saline-alkali soil in the third season, the income increase of K3 is 230.36 yuan compared with the income increase of K0 mu of farmers who are used for fertilizing, and the income increase of mu is 148.76 purely because the cost of the microbial remediation bactericide for soil is increased; compared with the K2 treatment method, the K3 has consistent cost investment, the effect of microorganisms is increased by K3 compared with K2, and the pure income per mu is increased by 74.78 yuan.

TABLE 9.2019 analysis table of wheat benefit

The soil microbial remediation microbial inoculum is 2.00 yuan kg (sold in the market), and the wheat price is 2.6 yuan kg in 2019.

TABLE 10.2019 analysis chart of maize profit situation

The soil microbial remediation microbial inoculum is 2.00 yuan kg (sold in the market), and the price of the corn in 2018 is 2.5 yuan kg.

As can be seen from Table 10, when corns are planted on the saline-alkali soil in the fourth season, the K3 is 207.07 yuan higher than that of the K0 mu of pure income increase of 104.69 yuan when farmers are used for applying fertilizers; compared with the K2 treatment method, the K3 treatment method has consistent cost investment, and the K3 treatment method increases the effect of microorganisms compared with the K2 treatment method, so that the pure income per mu is increased by 129.35 yuan.

Example 2

On the basis of the example 1, phosphogypsum is pretreated, and the method comprises the following steps: introducing 200-250 ℃ hot air into the phosphogypsum with the water content of 18-30% in a rotary kiln for drying, and in the drying process, a crushing mechanism is arranged in the rotary kiln for crushing the phosphogypsum into phosphogypsum powder. The rest is the same as example 1.

Example 3

On the basis of the embodiment 2, 4 to 5 parts by weight of soy sauce residues are also added in the step S1. The rest is the same as example 1.

Example 4

Based on example 3, 8-12 parts by weight of orange vinegar residue is also added in step S1. The rest is the same as example 3.

Example 5

5-15 parts by weight of expandable graphite is added in step S2 on the basis of example 4. The rest is the same as example 3.

In step S2, 3-5 parts by weight of diatomaceous earth is added.

TABLE 11 Effect of examples 2-5 on soil pH improvement

As can be seen from Table 11, the addition of the citrus pulp for treatment can prolong the slow release of the soil conditioner and further prolong the action time of the soil conditioner for improving the soil performance, and meanwhile, the citrus vinegar residue has a low pH value, can neutralize alkaline substances in alkaline soil, and improves the repairing effect.

The fluorine release amount of the remediation microbial inoculum prepared in the embodiment 1-5 is detected, and the specific detection method comprises the following steps: 5g of the microbial composite inoculum is put into a 100ml serum bottle (polyethylene plastic serum bottle), 100ml of ultrapure water (namely an extractant) is added, and the sample is taken by shaking at the rotating speed of 250r/min for 20min at room temperature (25 +/-2 ℃). 3ml of liquid in the bottle is extracted by a disposable syringe, filtered by a 0.45 cellulose acetate filter, and finally the content of the fluorinion in the filtrate is measured by adopting a water quality fluorinion measuring ion selective electrode method (GB 7484-87). The results are given in Table 12 below.

TABLE 12 detection of fluorine content in soil remediation Agents made according to the different examples

	Fluorine release amount mg/g
		Example 1	0.36
Example 2	0.24
		Example 3	0.21
Example 4	0.21
		Example 5	0.19

It is clear from table 12 that the phosphorous gypsum pretreatment of examples 4-5 reduces the amount of fluorine released.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.