CN112410265A

CN112410265A - Microbial agent and method for planting plants to improve tailing sand

Info

Publication number: CN112410265A
Application number: CN202011427835.7A
Authority: CN
Inventors: 许灏; 孙健; 徐连生; 赵虹; 陈晓寒; 崔兆杰; 赵睿
Original assignee: Ansteel Mining Co Ltd
Current assignee: Ansteel Mining Co Ltd
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2021-02-26

Abstract

The inventionRelates to a microbial agent which is activated, propagated and diluted into effective bacteria with the number concentration of 1 multiplied by 10 respectively⁷～9×10⁷CFU/mL is prepared by mixing bacterial liquids of bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus with equal volume. The invention also relates to a method for planting the plant improved tailing sand by the microbial agent, which comprises the following steps: adding 10-30 wt% of waste rocks with the particle size of 0.5-1.5 cm into tailing sandy soil with the depth of 25-40 cm, covering with 1-3 cm of additional soil, and turning for 15-20 cm; then applying 10-30 g/m of microbial agent²0.1-0.5 kg/m of organic fertilizer²And 5 to 20 soil organisms/m²And then planting the plants. The microbial agent can generate a mycorrhizal symbiotic system with plants, and enhances the capability of fixing and absorbing nutrients of plant roots, so that organic matters are nutritionally and circularly utilized. The method for improving the tailing sandy soil can increase the stability and the variety of systems and environments by adding soil organisms.

Description

Microbial agent and method for planting plants to improve tailing sand

Technical Field

The invention relates to the technical field of iron tailing sandy soil ecological restoration, in particular to a microbial agent and a method for improving tailing sandy soil by planting plants.

Background

Mining is an important basic industry of national economy in our country. According to statistics, more than 95% of primary energy, more than 80% of industrial raw materials and more than 70% of agricultural production data in China all come from mining industry. Due to the development and utilization of mineral resources, the original environmental landscape is seriously damaged and causes a series of ecological environmental problems. According to statistics, 50 hundred million tons of tailing sand are generated in iron ore development activities in China, about 5 hundred million tons of tailing discharge amount is increased every year, about 4 million hectares of land are damaged due to the increase of mining activities every year, and the vegetation reconstruction rate of the damaged land is only 13.3%. Therefore, the reuse of the iron tailings is a great problem which needs to be solved urgently at present. The iron tailings are subjected to sand-earthing treatment, so that the problem that a large amount of tailings are not placed everywhere can be solved, and the pressure of land destruction can be relieved.

Although the iron tailings are mixed into the soil according to a certain proportion, the physicochemical property of the soil can be improved, and the plant growth is facilitated, the problems of low organic nutrient content, difficult long-acting effect and the like caused by lack of organic nutrients in the process of the sandy utilization of the iron tailings are not avoided.

The method for improving the iron tailing sandy soil is mainly used for mine ecological restoration, and comprises vegetation recovery, mining area reclamation, tailing utilization technologies, and application technologies of various additives, microbial agents, adhesives, water retention agents and the like in soil improvement, wherein the application technologies comprise the following reports:

CN201810689836.5 discloses an iron tailing sandy soil modifier and an iron tailing sandy soil modification method, wherein the iron tailing sandy soil modifier comprises biochar, rice hulls, ceramsite, organic fertilizer, attapulgite powder and planting soil. The modifier improves the soil granularity, slows down the water loss rate in the soil, enhances the water retention performance, can quickly and effectively supplement the organic matter content, improves the porosity of the iron tailing sandy soil, reduces the hardening degree of the soil, and ensures that the tailing sandy soil keeps good ventilation and soft state for a long time, thereby being beneficial to the respiration of soil animals and plants and improving the survival rate.

CN201911344425.3 discloses a soda saline-alkali soil modifier containing combined microbial inoculum, which is prepared from the following components in parts by weight: 1.0-1.4 mL: 4-5 g: 1.5-1.8 g; the combined microbial inoculum consists of Azospirillum brasilense, Bacillus licheniformis and Zutongo pseudomonas. The combined microbial inoculum adopted by the invention is simple to produce and convenient to apply, can improve the biomass and the survivability of the plants, and can improve the physical and chemical properties of the soil.

The iron tailings have small particle size, so that the porosity between slag is small, and even a small amount of water is added, the air permeability is obviously weakened, and the growth of crops on the iron tailings is not facilitated. There is a need to improve the physical structure of iron tailings, for example, to bind small particle tailings to increase the particle size of the tailings, thereby increasing the permeability of the tailings.

In the prior art, the means for improving the physicochemical property of soil and promoting the increase of organic nutrients in soil are commonly compound fertilizers, nutrient additives and the like. However, as the compound fertilizer and the nutrient additive belong to external chemical additives, the physicochemical properties of the soil can be effectively improved and the organic nutrient content of the soil can be increased in a short time, but certain negative effects can be generated in a long term. Therefore, it is necessary to develop a technology that is ecological and environmentally friendly and can effectively improve soil.

In order to solve the problems that the tailings have small particle size and are easy to run off in the process of desertification utilization of the tailings, the inventor mixes the tailings in a mining area with waste rocks in a large number of tests, can effectively improve the air permeability of the tailings sandy soil, finds a microbial mixed microbial inoculum for improving the soil environment, and explores a method for improving the iron tailings sandy soil by planting plants by using the microbial inoculum.

Disclosure of Invention

The invention aims to provide a microbial agent.

The invention also aims to provide a method for cultivating the microbial agent for improving the tailings sandy soil by the plants.

The purpose of the invention is realized by the following technical scheme:

the microbial agent according to the present invention is characterized in that it is activated, propagated and diluted into effective bacteria at a number concentration of 1X 10⁷～9×10⁷The CFU/mL is prepared by mixing the bacterial liquids of bacillus subtilis CGMCC No.1.821, paecilomyces lilacinus CGMCC No.60794 and sphingosine bacillus ATCC 35656 in equal volume.

Further, the method for respectively activating, propagating and diluting the bacterial liquids of bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus multivorus in the microbial agent comprises the following steps:

respectively inoculating primary seeds of strains in a culture medium under an aseptic condition, and performing activation culture on each strain independently at the culture temperature of 23-27 ℃ for 7-10 days to obtain secondary seeds of the strains; digging small blocks, and respectively inoculating the small blocks into a large glass round culture dish for propagation culture at the culture temperature of 30-32 ℃ for 5-8 days, and the pH value of 6-7; collected and diluted to 1X 10⁷～9×10⁷CFU/mL bacterial liquid;

the activation and propagation culture medium is prepared by the following components: 1-3 g/L of nitrogen source, carbon source: 1-3 g/L, yeast extract: 1-3 g/L, peptone: 2-5 g/L, dipotassium hydrogen phosphate: 0.5-1 g/L, magnesium sulfate: 0.03-0.05 g/L.

The method for planting the plant improved tailing sand soil by using the microbial agent comprises the following steps:

(1) adding 10-30 wt% of waste rocks with the particle size of 0.5-1.5 cm into tailing sandy soil with the depth of 25-40 cm, and covering with foreign soil with the depth of 1-3 cm;

(2) applying 10-30 g/m in the sand soil of the iron tailings²A microbial agent, and 0.1-0.5 kg/m²The organic fertilizer is added with soil organisms as follows: the number of the earthworms, rotifers or nematodes is 5 to 20 per meter²Leveling and watering to ensure that the water holding rate of the soil is 60 +/-5%;

further, the method for planting the plant improvement tailings sandy soil by using the microbial agent comprises the steps of (1) and (2), ploughing the iron tailings sandy soil by 15-20 cm, planting the plant with the planting density of 15-30 plants/m 2, and performing field management.

Further, the plants are semen glycines and amorpha fruticosa, and the planting density is 10-20 plants/m²。

Still further, the soil organisms are: the number of the earthworms or nematodes is 10-15/m²。

The microbial agent disclosed by the invention is composed of bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus polyphagi, wherein the bacillus subtilis can obviously increase the contents of alkaline hydrolysis nitrogen and quick-acting phosphorus, quick-acting potassium and total potassium in soil. The organic matter content of the soil can be obviously increased under the action of the bacillus subtilis, so that nutrients of a plough layer are improved and adjusted, and the supply of nutrients required by the growth of crops is facilitated. The sphingosine bacillus multivorus can degrade pollutants in the soil environment, and particularly has a good repairing effect on the pollution of organic pollutants and pesticides. The paecilomyces lilacinus secretion can bond soil, increase the porosity of the soil, can produce a product similar to indoleacetic acid, has the most obvious physiological effects of promoting the growth of plant roots and plant nutritive organs, has a promoting effect on the germination and growth of seeds, can generate a mycorrhizal symbiosis system with plants, and strengthens the capability of fixing and absorbing nutrients of the plant roots so as to ensure the nutrient cyclic utilization of organic matters. The three microbial inoculums play different roles, can improve the soil environment, repair soil pollution, promote plant growth, and are mixed for application.

The method for improving the sandy soil of the tailings mainly comprises the steps of adding the waste rocks from a fine crushed product of a separation plant, carrying out magnetic separation on the waste rocks by using a magnetic pulley, and screening to obtain the tailings. The invention prepares novel soil by compounding the waste rock, the iron tailing sandy soil and the natural soil, can increase the air permeability of a compound system and improve the performance of the iron tailing sandy soil.

According to the method for improving the tailings sandy soil, earthworms or nematodes are added, the soil organisms have multiple functions of consumers, decomposers and regulators in an agricultural ecological system, the stability and the variety of the system and the environment can be improved, and the soil organisms can play a unique role in nutrient conversion and energy transfer in the soil, for example, the earthworms can penetrate in the soil to increase the air permeability of the soil; the earthworm and nematode excreta can in turn contribute more than 19% of the soluble nitrogen content of the soil.

The method for improving the tailing sandy soil is a technical method for effectively improving the soil, plants can adjust microclimate, reduce water evaporation and improve the water content of the soil, and the porosity of the soil is increased due to the interpenetration of plant roots to the soil. The microbial agent adopted by the invention can generate a mycorrhizal symbiotic system with plants, and the capability of fixing nutrients and absorbing nutrients of plant root systems is enhanced, so that organic matters are nutritionally and circularly utilized.

The microbial agent and the method for planting the plant to improve the tailing sand soil are characterized in that:

(1) the method has the advantages that three bacteria liquids of the bacillus subtilis, the paecilomyces lilacinus and the sphingosine bacillus polyphylla are combined for application, the production method is simple, the application is convenient, the action duration is long, the biomass and the survivability of plants can be improved, the physicochemical property of soil can be improved, the iron tailing sandy soil can be further improved by the aid of the mixed bacteria of the three microorganisms through combination of the plants and the soil animals, the harmless improvement effect is achieved, and the improvement effect is better through tests.

(2) The iron tailings and the waste rocks are utilized in a soil mode, the problems that the tailings sand is low in porosity and easy to run off are solved, the cooperative large-scale utilization of the tailings sand and the waste rocks in a mining area is realized, the ecological restoration in the mining area is long-acting and stable, the environment is continuously improved through greening, and the tailings sand and the waste rocks are changed into valuables.

(3) The invention utilizes the iron tailing sandy soil and the waste rocks to solve the problem of large-scale accumulation of mine wastes, relieves the atmospheric dust and soil pollution around a mining area, and reduces the risks of dam collapse, ecological landslide and the like of a tailing pond.

Detailed Description

The following examples are provided for illustrative purposes only and are not intended to limit the scope of the claims, and other alternatives that may occur to those skilled in the art from consideration of the specification are intended to be within the scope of the claims.

The implementation place of the method is a flat open space located on the southeast side of the large solitary mountain tailing waste area. The soil is high in terrain, sufficient in illumination, flat in terrain, free of other uses in recent years, and suitable for simulating an ecological restoration test in a tailing pond. The numerical conditions of the tailings sandy soil performance indexes in the test area are as follows:

index (I)	Detection value
		Volume weight (g/cm)³)	1.57
Total porosity(％)	44.68
		Water content (%)	11.88
pH value	8.75
		Organic matter content (g/kg)	1.15
Cu(mg/kg)	12.5
		Mn(mg/kg)	1070
Cd(mg/kg)	0.69

Example 1

A method for activating, expanding propagation and diluting bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus multivorus comprises the following steps:

respectively inoculating primary seeds of strains in a culture medium under an aseptic condition, and performing activation culture on each strain independently at the culture temperature of 25 ℃ for 7-8 days to obtain secondary seeds of the strains; digging small blocks, and inoculating into a large glass round culture dish for propagation culture at 32 deg.C for 8 days with pH of 6.5; collected and diluted to 1X 10⁷～9×10⁷CFU/mL bacterial liquid;

the activation and propagation culture medium is prepared by the following components: nitrogen source 2g/L, carbon source: 2g/L, yeast extract: 2g/L, peptone: 3g/L, dipotassium hydrogen phosphate: 1g/L, magnesium sulfate: 0.04 g/L.

Example 2

A method for planting a microbial agent for improving tailing sand by plants comprises the following steps:

(1) adding 20 wt% of waste rocks with the particle size of 0.5-1.5 cm into tailing sandy soil with the depth of 35cm, turning, uniformly mixing, and covering with 2.5cm of additional soil;

(2) applying 15g/m²The microbial agent prepared in the example 1 has the following effective bacteria in number concentration: 3X 10⁷CFU/mL of a mixed microbial inoculum with equal volume of bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus liquid, 0.32kg/m is added²Adding 10 earthworms/m into the chicken manure²Leveling and watering are carried out, the water holding rate of the soil is 60% +/-5%, and the soil is aged for one week.

The numerical conditions of the performance indexes of the tailings sandy soil after one week of curing are as follows:

index (I)	Detection value
		Volume weight (g/cm)³)	1.2～1.5
Total porosity (%)	50％～65％
		Water content (%)	15％～20％
pH value	6～8，
		Organic matter content (g/kg)	5～15

The performance index value of the tailings sandy soil is as follows: the volume weight, the total porosity, the water content, the pH value and the organic matter content reach the range suitable for planting the plant soil.

(3) Planting soybeans in the sand soil of the iron tailings with the planting density of 15 plants/m²And performing field management.

The three repeated tests are carried out, sampling analysis is carried out respectively in 1 month, 2 months and 3 months after sowing, various physical and chemical indexes of the soil are measured, and the test results of the physical and chemical indexes of the soil and plants in 3 months are shown in the following table 1.

TABLE 1

Example 3

the weight percentage of the added waste rock is as follows: 10% by weight, the procedure and procedure were the same as in example 2, and the results are shown in Table 2 below.

TABLE 2

Example 4

the number concentration of effective bacteria is as follows: 6X 10⁷CFU/mL, the same procedure and procedure as in example 2, and the results are shown in Table 3 below.

TABLE 3

Example 5

the number concentration of effective bacteria is 9 × 10⁷CFU/mL, the same procedure and procedure as in example 2, and the results are shown in Table 4 below.

TABLE 4

Example 6

the addition amount of the microbial agent is as follows: 25g/m²The procedure and procedure were the same as in example 2, and the results are shown in Table 5 below.

TABLE 5

Example 7

the plants planted were: the procedure and procedure were the same as in example 2, and the results are shown in Table 6 below.

TABLE 6

Example 8

the soil organisms added are: the nematodes were obtained in the same manner and procedure as in example 2, and the results are shown in Table 7 below.

TABLE 7

Comparative example 1

applying effective bacteria at a number concentration of 3 × 10⁷The procedure of example 2 was the same as that of example 2 except for the use of one strain of Paecilomyces lilacinus CFU/mL, and the results are shown in Table 7 below.

TABLE 7

Comparative example 2

applying effective bacteria at a number concentration of 3 × 10⁷CFU/mL of Bacillus subtilis, a bacterial preparation, was prepared in the same manner as in example 2, and the results are shown in Table 8 below.

TABLE 8

Comparative example 3

applying effective bacteria at a number concentration of 3 × 10⁷CFU/mL of a Sphingobacterium multivorum strain, the procedure and procedure were the same as in example 2, and the results are shown in Table 9 below.

TABLE 9

Comparative example 4

applying a quantitative concentration of 3X 10 containing the same effective bacteria⁷CFU/mL of a mixed bacterial preparation of bacterial solutions of Bacillus subtilis and Paecilomyces lilacinus in equal volumes, the other methods and procedures were the same as in example 2, and the results are shown in Table 10 below.

Watch 10

Comparative example 5

applying the same effective bacteria at a quantitative concentration of 3X 10⁷The same procedure as in example 2 was repeated except for using CFU/mL of a mixed bacterial preparation of the bacterial solutions of Paecilomyces lilacinus and Sphingobacterium multivorum in the same volume, and the results are shown in Table 11 below.

TABLE 11

Comparative example 6

applying the same effective bacteria at a quantitative concentration of 3X 10⁷The same procedure and procedure as in example 2 were repeated except for the CFU/mL of a mixed bacterial preparation of Bacillus subtilis and Sphingobacterium multivorum in the same volume, and the results are shown in Table 12 below.

TABLE 12

Comparative example 7

the weight percentage of the waste stone is as follows: 5% by weight, the same procedure and procedure as in example 2 were followed, and the results are shown in Table 13 below.

Watch 13

Comparative example 8

the weight percentage of the waste stone is as follows: 35% by weight, the same procedure and procedure as in example 2 were followed, and the results are shown in Table 14 below.

TABLE 14

Comparative example 9

the number concentration of the effective bacteria of the three microbial liquid is as follows: 5X 10⁶CFU/mL, the same procedure and procedure as in example 2, and the results are shown in Table 15 below.

Watch 15

Comparative example 10

the number concentration of the effective bacteria of the three microbial liquid is as follows: 1.2X 10⁸CFU/mL, the same procedure and procedure as in example 2, and the results are given in Table 16 below.

TABLE 16

Comparative example 11

the addition amount of the microbial agent is as follows: 5g/m²The procedure and procedure were the same as in example 2, and the results are shown in Table 17 below.

TABLE 17

Comparative example 12

the addition amount of the microbial agent is as follows: 40g/m²The procedure and procedure were the same as in example 2, and the results are shown in Table 18 below.

Watch 18

Comparative example 13

the three microbial solutions are mixed by bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus polyphagi according to the ratio of 1: 2: 2 and the other method and procedure were the same as in example 2, the results are shown in table 19 below.

Watch 19

Comparative example 14

the three microbial solutions are mixed by bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus polyphagi according to the ratio of 2: 1: 2, the other method and procedure were the same as in example 2, and the results are shown in table 20 below.

Watch 20

Comparative example 15

the procedure of example 2 was the same as that of example 2 except that the plant to be planted was capsicum, and the results are shown in table 21 below.

TABLE 21

Comparative example 16

the procedure was the same as in example 2 except that soil organisms were not added, and the results are shown in Table 22 below.

TABLE 22

For the physical and chemical property indexes of soil, when the water content in the soil reaches 15% -20%, the porosity of the soil is 50% -65%, and when the organic matter of the soil is 5-15 g/kg, the soil is the soil ecological environment for the growth of organisms and plants.

The test data results of the embodiments 2 to 8 show that various physical and chemical property indexes of the soil reach the ecological environment range suitable for planting the plant soil, and the soil shows better effect along with the increase of time, which shows that the technical scheme of the invention can effectively improve the tailing sandy soil for a long time and improve the ecological environment; however, the soil of comparative examples 1 to 16 had poor physical and chemical properties. The concrete description is as follows.

As can be seen from the comparison between examples 2 and 3 and comparative examples 7 and 8, the optimum addition ratio of the waste rock is preferably in the range of 10 to 30%, and the addition ratios of the waste rock are preferably in the ranges of 5% and 40%. The effects of effectively loosening the soil and increasing the air permeability of the soil cannot be achieved when the addition amount of the waste rocks is less than 10 percent, so that the soil is bonded, and the porosity is poor; when the addition amount of the waste rocks is higher than 30%, the porosity in the soil is too large, so that the soil is too loose, the loss of water and nutrients is easily caused, and the growth of plants is not facilitated.

As can be seen by comparing examples 2, 4 and 5 with comparative examples 9 and 10, the number of effective bacteria of three microorganisms is increasedThe concentration is 1 × 10⁷～9×10⁷Has the best effect in the CFU/mL range, and the effect ratio of 5 multiplied by 10 is exerted in the range⁶CFU/mL concentration was much better, slightly better than 1.2X 10⁸Effect of CFU/mL number concentration. The influence of the concentration of the microbial inoculum on the physicochemical property of the soil is large, the effect of the microbial inoculum is limited when the concentration of the microbial inoculum is too low, and the effect saturation effect can be caused on one hand and the improvement effect on the soil is not obviously increased when the concentration of the microbial inoculum is too high; on the other hand, the cost is increased, and the cost of soil improvement is increased.

As can be seen from comparison of examples 2 and 6 with comparative examples 11 and 12, the application amount of the microbial agent is 10-30 g/m²Has the best effect within the range, and the effect exerted by the range is 5g/m in specific application amount²And 40g/m²It is good. The application amount of the microbial agent with low addition amount cannot reach the dosage which can exert the optimal effect, and the excessive application of the microbial agent can consume excessive nutrient substances in soil in the metabolic process, compete with plants for nutrients, and cause the growth of the plants to be limited.

In example 2, the results of comparison with comparative examples 1, 2, 3, 4, 5 and 6 show that the mixed bacterial solution of three microorganisms exerts better effects than the single microbial bacterial solution and the mixed bacterial solution of two microorganisms when the amounts and the number concentrations of the microbial agents are the same. The three microbial solutions are mixed to generate a synergistic effect due to the unique properties of the three microbial solutions, and the synergistic effect is expressed as improvement on the physical and chemical properties of soil and promotion on plant growth. Also, example 2 can be seen in comparison with comparative examples 13 and 14. The microbial inoculum prepared by mixing the bacterial liquids of the bacillus subtilis, the paecilomyces lilacinus and the sphingosine bacillus multivorus in equal volumes has better effect than the microbial inoculum prepared by other volume ratios.

In examples 2, 7 and 8, the mycorrhiza infection rate is 27.16% -38.18%, which shows that the symbiotic relationship between the microorganisms and the plants is established, and the plant-mycorrhiza synergistic effect can improve the physicochemical properties of the iron tailing sandy soil better. In contrast, in comparative example 15, when soybeans and amorpha fruticosa were changed into other plants, the mycorrhiza infection rate was very low, and the soil and plant indexes were also reduced, which indicates that the microorganisms in the research range may hardly establish symbiotic relationship with other plants, and thus cannot perform synergistic action.

Examples 2, 8 and comparative example 16 it can be seen that the combination with soil animals works better than the combination without soil animals, indicating that soil animals do play a role, mainly because their activity in the soil leads to an increase in the porosity of the soil and that the excretion of soil animals may increase the content of organic matter in the soil, further promoting the growth of plants.

On the basis of a large number of tests, the invention develops a method for cultivating a microbial agent for improving the tailing sand by plants. And test results show that the soil conditioner can well improve various physical and chemical indexes and properties of soil and promote the growth and development of plants.

Claims

1. A microbial bacterial preparation features that it is activated, propagated and diluted to become effective bacteria whose number concentration is 1X 10⁷～9×10⁷CFU/mL bacillus subtilis CGMCC No.1.821, Paecilomyces lilacinus CGMCC No.60794 and Sphingobacterium multivorum ATCC 35656 are mixed in equal volume.

2. The microbial agent according to claim 1, wherein the method for activating, expanding and diluting the bacterial liquid of bacillus subtilis, paecilomyces lilacinus and sphingosine bacillus multivorus comprises the following steps:

3. The microbial agent according to claim 1, wherein the method for planting the plant improved tailing sand comprises the following steps:

(1) adding 10-30 wt% of waste rocks with the particle size of 0.5-1.5 cm into tailing sandy soil with the depth of 25-40 cm, and covering with foreign soil with the particle size of 1-3 cm;

(2) applying 10-30 g/m in iron tailing sand soil²A microbial agent, and 0.1-0.5 kg/m²The organic fertilizer is added with soil organisms as follows: the number of the earthworms, rotifers or nematodes is 5 to 20 per meter²Leveling and watering to ensure that the water holding rate of the soil is 60 +/-5%;

4. the method for cultivating the plant to improve the tailings sandy soil by using the microbial agent as claimed in claim 3, wherein after the steps (1) and (2) are carried out, the iron tailings sandy soil is ploughed by 15-20 cm, then the plant is cultivated, and the planting density is 15-30 plants/m²And performing field management.

5. The method for cultivating plants to improve the sandy soil of tailings by using the microbial agent as claimed in claim 4, wherein the plants are soybeans and amorpha fruticosa, and the planting density is 10-20 plants/m²。

6. The method for cultivating plants to improve the sandy soil of tailings according to the microbial inoculum of claim 3, wherein the soil organisms are: the number of the earthworms or nematodes is 10-15/m²。