Ecological restoration method for facility vegetable continuous cropping obstacle soil

Abstract

The invention relates to the technical field of soil remediation, in particular to an ecological remediation method for greenhouse vegetable continuous cropping obstacle soil. Comprising the following steps: S1, applying mixed gel loaded with a microbial agent into soil, and turning over the soil; s2, water is injected into the soil, then the greenhouse is closed, and after the greenhouse is closed for 6-8 days, a greenhouse door is opened for ventilation; s3, the greenhouse closing and ventilation operation in the step S2 is repeatedly implemented for 2-4 times, and in the ventilation process, remediation liquid is dripped into the soil in a drip irrigation mode; and S4, after airing is conducted for 5-7 days, repairing is completed. According to the method, pathogenic bacteria in soil are eliminated through combination of greenhouse closing and the microbial agent, the mixed gel can protect the microbial agent and avoid death of the microbial agent during greenhouse closing, then greenhouse closing and ventilation are alternately carried out, the microbial agent is gradually released, meanwhile, repair liquid is supplemented to improve the survival rate of the microbial agent, and rapid proliferation is achieved; the soil environment can be quickly restored.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and in particular to an ecological remediation method for continuous cropping obstacle soil of protected vegetables. Background Art

[0002] Continuous cropping obstacle refers to the phenomenon that when the same or the same family of crops are continuously planted in the same piece of soil, even with normal management, the growth potential is weak, the yield is reduced, and the quality is deteriorated. This is because continuous cultivation of the same crop for several years has propagated a large number of harmful microbial populations in the soil, while the activities of beneficial microorganisms in the soil, such as nitrifying bacteria and ammonifying bacteria, are inhibited, thus changing the microbial flora in the soil, resulting in an imbalance in the proportion of microbial numbers in the soil. The applied fertilizers cannot be effectively decomposed, leading to uneven distribution of soil nutrients, exacerbating the spread of soil-borne diseases, and causing soil environmental deterioration and ecological imbalance.

[0003] At present, there are various methods to relieve continuous cropping obstacles, including physical methods and chemical methods, such as applying microbial agents, high-temperature sterilization, increasing the application of organic fertilizers, reasonable irrigation, grafting and root replacement, soil replacement method, etc. However, the repair effect of the physical method is poor, and when using microbial agents, the microbial agents will also be lost due to precipitation and other reasons, resulting in poor repair effect. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides an ecological remediation method for continuous cropping obstacle soil of protected vegetables.

[0005] The technical solution of the present invention is: an ecological remediation method for continuous cropping obstacle soil of protected vegetables, characterized by including the following steps:

[0006] S1. Apply a mixed gel loaded with a microbial agent to the soil, and the application amount of the mixed gel loaded with the microbial agent is 200 - 300 kg per mu, and then plow the soil;

[0007] S2. After the plowing is completed, inject water into the soil, and the water injection amount is 50 - 60 L per mu. After the water injection is completed, cover the soil surface with a plastic film, and then close the shed door for soil steaming. After 6 - 8 days of soil steaming, open the shed door for ventilation, and the ventilation time is 1 - 2 days;

[0008] S3. Repeat the soil steaming and ventilation operations described in step S2 for 2 - 4 times, and each subsequent soil steaming time is reduced by 0.5 - 1.5 days compared with the previous time, and a repair liquid is drip-irrigated into the soil once during each ventilation process, and the drip-irrigation amount of the repair liquid is 2 - 3 L per mu;

[0009] S4. After step S3 is completed, remove the plastic film, and dry it for 5 - 7 days to complete the repair.

[0010] Description: The above-mentioned repair method improves the water storage performance of the soil and adsorbs heavy metal ions in the soil by applying a mixed gel loaded with microbial agents, and then eliminates pathogenic bacteria in the soil by combining soil covering and microbial agents. The mixed gel can form a physical barrier to protect the microbial agents and prevent the death of microbial agents during soil covering. By alternating soil covering and ventilation operations, while the repair solution replenishes nutrients to the soil, the mixed gel can gradually release the microbial agents, improve the survival rate of the microbial agents and rapidly proliferate, and quickly repair the soil environment.

[0011] Further, in step S1, the tillage depth is 20 - 30 cm.

[0012] Description: Tillage can loosen the soil and expose pathogenic bacteria on the soil surface, ensuring the subsequent soil covering effect.

[0013] Further, in step S1, the preparation method of the mixed gel loaded with microbial agents includes the following steps:

[0014] S1-1. Dissolve polyvinyl alcohol in deionized water at 80 - 90 °C and stir for 2 - 4 h to obtain a first mixed solution; wherein, the mass ratio of polyvinyl alcohol to deionized water is 1:10 - 20;

[0015] S1-2. Add sodium alginate to the first mixed solution, stir for 10 - 15 min, and then continue to add microbial agents to the first mixed solution and ultrasonically disperse for 1 - 2 h to obtain a second mixed solution; wherein, the addition amount of sodium alginate accounts for 2 - 5% of the initial mass of the first mixed solution, and the addition amount of microbial agents accounts for 20 - 30% of the initial mass of the first mixed solution;

[0016] S1-3. Drop the second mixed solution into the cross-linking agent. After the dropping is completed, let the cross-linking agent stand at 0 - 5 °C for 20 - 24 h, and then filter to obtain gel beads; wherein, the mass ratio of the second mixed solution to the cross-linking agent is 1:1 - 1.5;

[0017] S1-4. Wash the gel beads, and after the washing is completed, obtain the mixed gel loaded with microbial agents.

[0018] Description: The above method forms a gel by mixing polyvinyl alcohol and sodium alginate, and entraps microbial agents inside the mixed gel under the action of the cross-linking agent. The good thermal stability of the mixed gel provides a thermal buffer for the microbial agents to prevent the death of microbial agents during soil covering, and the mixed gel can gradually release the microbial agents under the action of the repair solution, enabling the microbial agents to gradually adapt to the environment and ensuring the survival rate.

[0019] Furthermore, in step S1-2, the components of the microbial agent include, by weight: 8-12 parts of Bacillus subtilis, 5-10 parts of Trichoderma harzianum, 5-10 parts of Trichoderma viride, 10-15 parts of Bacillus velezensis, 20-30 parts of sucrose, and 300-500 parts of deionized water.

[0020] Description: The above-mentioned microbial agents can decompose plant residues, promote the formation of soil aggregate structure, improve the soil's ability to retain water and fertilizer, stabilize the soil pH value, and inhibit the reproduction of pathogens.

[0021] Furthermore, in step S1-3, the dripping rate is 2-4 mL / min, and the droplet diameter is 2-5 mm.

[0022] Note: Limiting the dripping rate and droplet diameter can ensure that the mixed gel is fully formed and forms gel balls with uniform particle size, avoiding affecting the strength of the mixed gel.

[0023] Furthermore, the cross-linking agent comprises, by weight, 8 to 15 parts of citric acid, 5 to 10 parts of calcium carbonate, and 80 to 90 parts of deionized water.

[0024] Note: The above cross-linking agent dissolves calcium carbonate through citric acid to release calcium ions, so that polyvinyl alcohol and sodium alginate can complete cross-linking under the action of calcium ions, ensuring the strength of the mixed gel.

[0025] Furthermore, during the dripping process, calcium chloride is added to the crosslinking agent every time the volume of the crosslinking agent increases by 20-30% compared to its initial volume, and the amount of calcium chloride added accounts for 0.2-0.4% of the initial mass of the crosslinking agent.

[0026] Note: Supplementing calcium chloride can promote the secondary cross-linking of the mixed gel and enhance the stability of the gel.

[0027] Furthermore, in step S3, the components of the repair fluid include, by weight, 25-40 parts of ethylenediaminetetraacetic acid, 30-40 parts of ammonium phosphate, 20-30 parts of potassium nitrate, and 400-600 parts of water.

[0028] Description: The above-mentioned repair liquid can add nutrients to the soil, so that there is sufficient nutrition for the proliferation of microorganisms. At the same time, EDTA can chelate the calcium ions in the mixed gel, decompose the cross-linked structure of the mixed gel and release microbial agents. At the same time, EDTA can chelate with heavy metal ions and reduce the concentration of heavy metal ions in the soil.

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention eliminates pathogenic bacteria in the soil through the combination of soil steaming and microbial inoculants, and the mixed gel can form a physical barrier to protect the microbial inoculants, avoiding the death of microbial bacteria during soil steaming. Then, through the alternation of soil steaming and ventilation operations, while the repair solution replenishes nutrients to the soil, the mixed gel loaded with microbial inoculants can gradually release the microbial inoculants, improving the survival rate of microbial bacteria and rapidly multiplying them, and quickly repairing the soil environment.

[0031] (2) The present invention forms a gel by mixing polyvinyl alcohol and sodium alginate, and embeds microbial inoculants inside the mixed gel under the action of a cross-linking agent. The good thermal stability of the mixed gel provides a thermal buffer for the microbial inoculants, avoiding the death of microbial bacteria during soil steaming, and the mixed gel can gradually release the microbial inoculants under the action of the repair solution, enabling the microbial inoculants to gradually adapt to the environment and ensuring the survival rate.

[0032] (3) The repair solution of the present invention can supplement nutrients to the soil, providing sufficient nutrition for the proliferation of microbial bacteria. At the same time, ethylenediaminetetraacetic acid can chelate calcium ions in the mixed gel, causing the cross-linked structure of the mixed gel to decompose and release the microbial inoculants. At the same time, ethylenediaminetetraacetic acid can chelate with heavy metal ions, reducing the concentration of heavy metal ions in the soil. Specific Embodiments

[0033] To further illustrate the methods and achieved effects adopted by the present invention, the technical solutions of the present invention will be clearly and completely described below in combination with experiments.

[0034] Example 1: An ecological restoration method for continuous cropping obstacle soil of protected vegetables, characterized by comprising the following steps:

[0035] S1. Apply the mixed gel loaded with microbial inoculants to the soil, and the application amount of the mixed gel loaded with microbial inoculants is 250 kg per mu, and then plow the soil; wherein, the plowing depth is 25 cm;

[0036] S2. After plowing, inject water into the soil, and the water injection amount is 55 L per mu. After the water injection is completed, cover the soil surface with a plastic film, and then close the shed door for soil steaming. After 7 days of soil steaming, open the shed door for ventilation, and the ventilation time is 1.5 days;

[0037] S3. Repeat the soil steaming and ventilation operations described in step S2 three times, and the soil steaming time in each subsequent time is reduced by 1 day compared with the previous time, and a repair solution is drip-irrigated into the soil once during each ventilation process, and the drip-irrigation amount of the repair solution is 2.5 L per mu;

[0038] The components of the repair solution include, by weight, 32 parts of ethylenediaminetetraacetic acid, 35 parts of ammonium phosphate, 25 parts of potassium nitrate, and 500 parts of water;

[0039] S4. After the implementation of Step S3, remove the plastic film and air-dry for 6 days to complete the repair.

[0040] The preparation method of the mixed gel loaded with microbial inoculum comprises the following steps:

[0041] S1-1. Dissolve polyvinyl alcohol in deionized water at 85°C and stir for 3 h to obtain a first mixed solution. Among them, the mass ratio of polyvinyl alcohol to deionized water is 1:15.

[0042] S1-2. Add sodium alginate to the first mixed solution, stir for 12 min, and then continue to add the microbial inoculum to the first mixed solution and ultrasonically disperse for 1.5 h to obtain a second mixed solution. Among them, the addition amount of sodium alginate accounts for 4% of the initial mass of the first mixed solution, and the addition amount of the microbial inoculum accounts for 25% of the initial mass of the first mixed solution.

[0043] The components of the microbial inoculum include, by weight: 10 parts of Bacillus subtilis, 8 parts of Trichoderma harzianum, 8 parts of Trichoderma viride, 12 parts of Bacillus velezensis, 25 parts of sucrose, and 400 parts of deionized water. Among them, the strain number of Bacillus subtilis is CICC 10732, the strain number of Trichoderma harzianum is CICC 13010, the strain number of Trichoderma viride is CICC 13038, and the strain number of Bacillus velezensis is CICC 21430.

[0044] S1-3. Drop the second mixed solution into the cross-linking agent. After the dropping is completed, let the cross-linking agent stand at 2°C for 22 h, and then filter to obtain gel beads. Among them, the mass ratio of the second mixed solution to the cross-linking agent is 1:1.2; the dropping rate is 3 mL / min, and the droplet diameter is 4 mm.

[0045] The components of the cross-linking agent include, by weight: 12 parts of citric acid, 8 parts of calcium carbonate, and 85 parts of deionized water. And during the dropping process, every time the volume of the cross-linking agent increases by 25% compared with its initial volume, calcium chloride is added to the cross-linking agent once, and the addition amount of calcium chloride accounts for 0.3% of the initial mass of the cross-linking agent.

[0046] S1-4. Wash the gel beads, and after the washing is completed, obtain the mixed gel loaded with the microbial inoculum.

[0047] Example 2: This example is basically the same as Example 1, except that the application amount of the mixed gel loaded with the microbial inoculum is 200 kg per mu.

[0048] Example 3: This example is basically the same as Example 1, except that the application amount of the mixed gel loaded with the microbial inoculum is 300 kg per mu.

[0049] Example 4: This example is basically the same as Example 1, except that the shed door is closed for soil steaming. After 6 days of soil steaming, the shed door is opened for ventilation for 1 day.

[0050] Example 5: This example is basically the same as Example 1, except that the shed door is closed for soil steaming. After 8 days of soil steaming, the shed door is opened for ventilation for 2 days.

[0051] Example 6: This example is basically the same as Example 1, except that the soil steaming and ventilation operations described in step S2 are repeated 2 times.

[0052] Example 7: This example is basically the same as Example 1, except that the soil steaming and ventilation operations described in step S2 are repeated 4 times.

[0053] Example 8: This example is basically the same as Example 1, except that the subsequent soil steaming time is reduced by 0.5 days each time compared to the previous time.

[0054] Example 9: This example is basically the same as Example 1, except that the subsequent soil steaming time is reduced by 1.5 days each time compared to the previous time.

[0055] Example 10: This example is basically the same as Example 1, except that the drip irrigation amount of the repair liquid is 2 L per mu.

[0056] Example 11: This example is basically the same as Example 1, except that the drip irrigation amount of the repair liquid is 3 L per mu.

[0057] Example 12: This example is basically the same as Example 1, except that the components of the repair liquid by weight include 25 parts of ethylenediaminetetraacetic acid, 30 parts of ammonium phosphate, 20 parts of potassium nitrate, and 400 parts of water.

[0058] Example 13: This example is basically the same as Example 1, except that the components of the repair liquid by weight include 40 parts of ethylenediaminetetraacetic acid, 40 parts of ammonium phosphate, 30 parts of potassium nitrate, and 600 parts of water.

[0059] Example 14: This example is basically the same as Example 1, except that the addition amount of the microbial inoculum accounts for 20% of the initial mass of the first mixed liquid.

[0060] Example 15: This example is basically the same as Example 1, except that the addition amount of the microbial inoculum accounts for 30% of the initial mass of the first mixed liquid.

[0061] Example 16: This example is basically the same as Example 1, except that the ingredients of the microbial agent include, by weight: 8 parts of Bacillus subtilis, 5 parts of Trichoderma harzianum, 5 parts of Trichoderma viride, 10 parts of Bacillus velezensis, 20 parts of sucrose, and 300 parts of deionized water.

[0062] Example 17: This example is basically the same as Example 1, except that the ingredients of the microbial agent include, by weight: 12 parts of Bacillus subtilis, 10 parts of Trichoderma harzianum, 10 parts of Trichoderma viride, 15 parts of Bacillus velezensis, 30 parts of sucrose, and 500 parts of deionized water.

[0063] Example 18: This example is basically the same as Example 1, except that the mass ratio of the second mixed liquid to the cross-linking agent is 1:1.

[0064] Example 19: This example is basically the same as Example 1, except that the mass ratio of the second mixed liquid to the cross-linking agent is 1:1.5.

[0065] Example 20: This example is basically the same as Example 1, except that the components of the cross-linking agent include, by weight, 10 parts of citric acid, 5 parts of calcium carbonate and 80 parts of deionized water.

[0066] Example 21: This example is basically the same as Example 1, except that the components of the cross-linking agent include, by weight, 15 parts of citric acid, 10 parts of calcium carbonate and 90 parts of deionized water.

[0067] Example 22: This example is basically the same as Example 1, except that calcium chloride is added to the cross-linking agent every time the volume of the cross-linking agent increases by 20% compared to its initial volume during the instillation process. The amount of calcium chloride added accounts for 0.2% of the initial mass of the cross-linking agent.

[0068] Example 23: This example is basically the same as Example 1, except that calcium chloride is added to the cross-linking agent every time the volume of the cross-linking agent increases by 30% compared to its initial volume during the instillation process. The amount of calcium chloride added accounts for 0.4% of the initial mass of the cross-linking agent.

[0069] Comparative Example 1: No soil repair was performed.

[0070] Comparative Example 2: Taking Example 1 as a reference, instead of loading the mixed gel with the microbial agent, the microbial agent and the mixed gel were applied to the soil separately.

[0071] Comparative Example 3: Taking Example 1 as a reference, the time of each suffocation was constant at 7 days.

[0072] Comparative Example 4: Using Example 1 as a reference, the repair liquid was not drip-irrigated into the soil.

[0073] Comparative Example 5: Referring to Example 1, calcium chloride was not added to the crosslinking agent.

[0074] Experimental Example: In order to explore the influence of the parameters of each example on the soil remediation effect, the vegetable planting land in Xi'an, Shaanxi, which had been continuously cropped for 6 years, was used as the experimental object. 28 experimental areas were selected. After the soil was remediated by the methods of each example and comparative example, 1,800 tomato plants were planted on the soil of each experimental area, and the influence of the parameters of each example on the soil remediation effect was obtained. The specific exploration is as follows:

[0075] Experimental Example 1: Explore the influence of the application amount of the mixed gel loaded with microbial inoculum on the soil remediation effect

[0076] Taking Examples 1-3 and Comparative Examples 1-2 as experimental comparisons, the soil remediation effects under different application amounts of the mixed gel loaded with microbial inoculum are shown in Table 1 below:

[0077] Table 1 Soil remediation effects under different application amounts of the mixed gel loaded with microbial inoculum

[0078] Group Incidence rate Yield / kg Example 1 1.5％ 5463 Example 2 2.1％ 5021 Example 3 1.4％ 5474 Comparative Example 1 6.1％ 3358 Comparative Example 2 5.4％ 3694

[0079] It can be seen from the data in Table 1 that compared with Examples 1, 2, and 3: The tomato yield in Example 3 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 3 is better. Therefore, as the application amount of the mixed gel loaded with microbial inoculum increases, the soil remediation effect also improves. However, compared with Example 1, the increase in yield in Example 3 is less. Therefore, from the perspective of cost, the application amount of the mixed gel loaded with microbial inoculum selected in Example 1 is the most optimal;

[0080] Compared with Example 1 and Comparative Example 1: After the soil was not remediated, the incidence rate of tomatoes increased by 4.6% and the yield decreased by 38.5%. This shows that the remediation method in Example 1 can effectively increase the yield of the soil with continuous cropping obstacles of vegetables;

[0081] Compared with Example 1 and Comparative Example 2: After the microbial inoculum and the mixed gel were respectively applied to the soil, the incidence rate of tomatoes increased and the yield decreased significantly. This may be because the microbial inoculum failed to effectively proliferate in the soil. Therefore, the soil remediation method selected in Example 1 is more optimal.

[0082] Experimental Example 2: Explore the influence of the parameters of soil covering and ventilation on the soil remediation effect

[0083] Taking Examples 1, 4-9 and Comparative Example 3 as experimental comparisons, the soil remediation effects under different parameters of soil covering and ventilation are shown in Table 2 below:

[0084] Table 2 Soil remediation effects under different parameters of soil covering and ventilation

[0085] Group Incidence rate Yield / kg Example 1 1.5％ 5463 Example 4 1.9％ 5210 Example 5 2.3％ 4932 Example 6 2.0％ 5087 Example 7 1.8％ 5276 Example 8 2.2％ 4985 Example 9 1.9％ 5188 Comparative Example 3 4.2％ 4296

[0086] As can be seen from the data in Table 2, comparing Examples 1, 4, and 5: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because under the initial time of soil steaming and ventilation selected in Example 1, the amount of pathogenic bacteria eliminated is higher. Therefore, the initial time of soil steaming and ventilation selected in Example 1 is the optimal one;

[0087] Comparing Examples 1, 6, and 7: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because under the number of times of soil steaming and ventilation selected in Example 1, the activity of the microbial inoculant is the best. Therefore, the number of times of soil steaming and ventilation selected in Example 1 is the optimal one;

[0088] Comparing Examples 1, 8, and 9: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because under the reduction amount of soil steaming time selected in Example 1, the inactivation amount of the microbial inoculant is less and the proliferation rate is higher. Therefore, the reduction amount of soil steaming time selected in Example 1 is the optimal one;

[0089] Comparing Example 1 with Comparative Example 3: After the soil steaming time is constant each time, the incidence rate of tomatoes increases and the yield decreases significantly. This may be because the activity of the released microbial inoculant is lost due to the constant soil steaming time each time. Therefore, the remediation method selected in Example 1 is better.

[0090] Experimental Example 3. Explore the influence of the drip irrigation amount and composition of the remediation liquid on the soil remediation effect

[0091] Taking Examples 1, 10 - 13 and Comparative Example 4 as experimental comparisons, the soil remediation effects under different drip irrigation amounts and compositions of the remediation liquid are shown in Table 3 below:

[0092] Table 3 Soil remediation effects under different drip irrigation amounts and compositions of the remediation liquid

[0093] Group Incidence rate Yield / kg Example 1 1.5％ 5463 Example 10 1.8％ 5223 Example 11 1.6％ 5434 Example 12 2.0％ 5017 Example 13 1.7％ 5291 Comparative Example 4 3.8％ 4573

[0094] As can be seen from the data in Table 3, comparing Examples 1, 10, and 11: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because under the drip irrigation amount of the remediation liquid selected in Example 1, the humidity and nutrients in the soil are suitable for the growth of microorganisms. Therefore, the drip irrigation amount of the remediation liquid selected in Example 1 is the optimal one;

[0095] Comparing Examples 1, 12, and 13: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because under the composition of the remediation liquid selected in Example 1, the release rate of the microbial inoculant is the best. Therefore, the composition of the remediation liquid selected in Example 1 is the optimal one;

[0096] Example 1 compared with Comparative Example 4: After ceasing the drip irrigation of the remediation liquid into the soil, the incidence rate of tomatoes increased and the yield decreased significantly. This may be because the mixed gel loaded with the microbial inoculant could not decompose rapidly, resulting in the insufficient release of the microbial inoculant. Therefore, the remediation method selected in Example 1 is the optimal one.

[0097] Experimental Example 4. Exploration of the influence of the addition amount and components of the microbial inoculant on the soil remediation effect

[0098] Taking Examples 1, 14 to 17 as experimental comparative examples, the soil remediation effects under different addition amounts and components of the microbial inoculant are shown in Table 4 below:

[0099] Table 4. Soil remediation effects under different addition amounts and components of the microbial inoculant

[0100] Group Incidence rate Yield / kg Example 1 1.5％ 5463 Example 14 2.4％ 4841 Example 15 2.2％ 4957 Example 16 1.9％ 5225 Example 17 1.7％ 5387

[0101] From the data in Table 4, it can be seen that when comparing Examples 1, 14, and 15: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because at the addition amount of the microbial inoculant selected in Example 1, the protection effect of the mixed gel on the microbial inoculant is better. Therefore, the addition amount of the microbial inoculant selected in Example 1 is the optimal one;

[0102] When comparing Examples 1, 16, and 17: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because with the components of the microbial inoculant selected in Example 1, the microbial inoculant can effectively play a synergistic role in remediating the soil. Therefore, the components of the microbial inoculant selected in Example 1 are the optimal ones.

[0103] Experimental Example 5. Exploration of the influence of crosslinking agent addition parameters on the soil remediation effect

[0104] Taking Examples 1, 18 to 23 and Comparative Example 5 as experimental comparisons, the soil remediation effects under different addition parameters of the crosslinking agent are shown in Table 5 below:

[0105] Table 5. Soil remediation effects under different addition parameters of the crosslinking agent

[0106] Group Incidence rate Yield / kg Example 1 1.5％ 5463 Example 18 2.2％ 4985 Example 19 1.8％ 5230 Example 20 2.5％ 4812 Example 21 2.3％ 4981 Example 22 2.0％ 5114 Example 23 1.9％ 5197 Comparative Example 5 3.5％ 4668

[0107] From the data in Table 5, it can be seen that when comparing Examples 1, 18, and 19: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because at the ratio of the second mixed liquid to the crosslinking agent selected in Example 1, the structure of the mixed gel is the most stable and the protection effect on the microbial inoculant is better. Therefore, the ratio of the second mixed liquid to the crosslinking agent selected in Example 1 is the optimal one;

[0108] Compared with Examples 1, 20, and 21: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because under the cross-linking agent components selected in Example 1, the mixed gel can be fully cross-linked to encapsulate the microbial inoculant. Therefore, the cross-linking agent components selected in Example 1 are the best;

[0109] Compared with Examples 1, 22, and 23: The tomato yield in Example 1 is higher and the incidence rate is lower, indicating that the soil remediation effect in Example 1 is better. This may be because at the addition amount of calcium chloride selected in Example 1, the structure of the mixed gel is the most stable. Therefore, the addition amount of calcium chloride selected in Example 1 is the best;

[0110] Compared with Comparative Example 5: After not adding calcium chloride to the cross-linking agent, the incidence rate of tomatoes increases and the yield decreases significantly. This may be because the failure to add calcium chloride to the cross-linking agent results in the inability of the mixed gel to cross-link secondary, affecting the structure of the mixed gel. Therefore, the preparation method of the mixed gel loaded with microbial inoculant selected in Example 1 is the best.

Claims

1. An ecological restoration method for continuous cropping obstacle soil of protected vegetables, characterized in that, It includes the following steps: S1. Apply a mixed gel loaded with microbial inoculum to the soil. The application amount of the mixed gel loaded with microbial inoculum is 200 - 300 kg per mu, and then plow the soil; S2. After the plowing is completed, inject water into the soil. The water injection amount is 50 - 60 L per mu. After the water injection is completed, cover the soil surface with a plastic film, then close the shed door for soil steaming. After 6 - 8 days of soil steaming, open the shed door for ventilation for 1 - 2 days; S3. Repeat the soil steaming and ventilation operations described in step S2 for 2 - 4 times. And the soil steaming time for each subsequent time is reduced by 0.5 - 1.5 days compared with the previous time. And during each ventilation process, drip - irrigate a repair liquid into the soil once. The drip - irrigation amount of the repair liquid is 2 - 3 L per mu; S4. After step S3 is completed, remove the plastic film and dry it for 5 - 7 days to complete the repair.

2. The ecological restoration method for continuous cropping obstacle soil of protected vegetables according to claim 1, characterized in that In step S1, the plowing depth is 20 - 30 cm.

3. A method for ecological restoration of continuous cropping obstacle soil in protected vegetables according to claim 1, characterized in that, In step S1, the preparation method of the mixed gel loaded with microbial inoculum includes the following steps: S1 - 1. Dissolve polyvinyl alcohol in deionized water at 80 - 90 °C and stir for 2 - 4 h to obtain a first mixed solution. Wherein, the mass ratio of polyvinyl alcohol to deionized water is 1:10 - 20; S1 - 2. Add sodium alginate to the first mixed solution. After stirring for 10 - 15 min, continue to add microbial inoculum to the first mixed solution and ultrasonically disperse for 1 - 2 h to obtain a second mixed solution. Wherein, the addition amount of sodium alginate accounts for 2 - 5% of the initial mass of the first mixed solution, and the addition amount of microbial inoculum accounts for 20 - 30% of the initial mass of the first mixed solution; S1 - 3. Drop - inject the second mixed solution into the cross - linker. After the drop - injection is completed, let the cross - linker stand at 0 - 5 °C for 20 - 24 h, and then filter to obtain gel beads. Wherein, the mass ratio of the second mixed solution to the cross - linker is 1:1 - 1.5; S1 - 4. Wash the gel beads, and after the washing is completed, obtain the mixed gel loaded with microbial inoculum.

4. A method for ecological restoration of continuous cropping obstacle soil in protected vegetables according to claim 3, characterized in that, In step S1 - 2, the components of the microbial inoculum by weight include: 8 - 12 parts of Bacillus subtilis, 5 - 10 parts of Trichoderma harzianum, 5 - 10 parts of Trichoderma viride, 10 - 15 parts of Bacillus velezensis, 20 - 30 parts of sucrose, and 300 - 500 parts of deionized water.

5. A method for ecological restoration of continuous cropping obstacle soil in protected vegetables according to claim 3, characterized in that In step S1 - 3, the drop - injection rate is 2 - 4 mL / min, and the droplet diameter is 2 - 5 mm.

6. The ecological restoration method for continuous cropping obstacle soil of protected vegetables according to claim 3, characterized in that, The components of the cross - linker by weight include 10 - 15 parts of citric acid, 5 - 10 parts of calcium carbonate, and 80 - 90 parts of deionized water.

7. The ecological restoration method for continuous cropping obstacle soil of protected vegetables according to claim 6, wherein, During the drop - injection process, every time the volume of the cross - linker increases by 20 - 30% compared with its initial volume, add calcium chloride to the cross - linker once. The addition amount of calcium chloride accounts for 0.2 - 0.4% of the initial mass of the cross - linker.

8. The ecological restoration method for continuous cropping obstacle soil of protected vegetables according to claim 1, characterized in that In step S3, the components of the repair liquid by weight include 25 - 40 parts of ethylenediaminetetraacetic acid, 30 - 40 parts of ammonium phosphate, 20 - 30 parts of potassium nitrate, and 400 - 600 parts of water.