Method for improving saline-alkali soil and application

Abstract

The invention relates to the field of comprehensive treatment of saline-alkali soil, and discloses a method for improving saline-alkali soil and application. The method comprises the following steps: burying a pre-burying agent in soil of soda saline-alkali soil with the water content of 20-35wt%; applying an eluting agent to the soil; after crops are planted, a microbial agent is applied through a drip irrigation system; the eluting agent comprises modified or unmodified polysiloxane, and the surface active agent comprises sulfonate of C5-C20. According to the method, the soda saline-alkali soil is improved by using the specific modifier and the method, so that the salt content and the pH value of the saline-alkali soil are reduced, the soil aggregate structure of the saline-alkali soil is improved, the content of organic components and humus in the soil is increased, the productivity of the soda saline-alkali soil is improved, and the adaptability and the tolerance of crops to adverse environments are enhanced. The improvement period of the saline-alkali soil can be further shortened, the comprehensive cost of large-scale improvement is reduced, and meanwhile the stability of the improvement effect is improved.

Description

Technical Field

[0001] This invention relates to the field of comprehensive management of saline-alkali land, specifically to a method and application for improving saline-alkali land. Background Technology

[0002] Soda saline-alkali land is a type of saline-alkali land. Its main salts are NaHCO3 and Na2CO3, with small amounts of sulfates and chlorides. Its pH is 9-11. It suffers from strong alkalinity, mixed salt and alkali stress, poor permeability, low basic soil fertility, lack of organic matter, difficulty in cultivation, and slow effectiveness of conventional improvement methods.

[0003] Currently, methods for improving the soil structure of saline-alkali land include: physical remediation, such as land leveling, deep plowing and sun-drying, and adding topsoil to suppress alkali, but these are costly and have limited effectiveness; chemical remediation, such as applying gypsum, superphosphate, humic acid, and calcium silicate minerals, can remove some soluble salt ions and exchangeable sodium from the soil, but its effect on improving soil structure is limited; biological methods are time-consuming and ineffective for severely soda-alkali land.

[0004] Therefore, there is an urgent need to develop a reagent and a method for improving soda saline-alkali land, in order to reduce alkali, desalinate, and fertilize, increase soil aggregates and porosity, and improve the soil structure of soda saline-alkali land. Summary of the Invention

[0005] The purpose of this invention is to overcome the aforementioned problems in the prior art and to provide a method and application for improving saline-alkali land.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for improving saline-alkali land, the method comprising: (1) Bury the pre-embedded agent in the soil of soda saline-alkali land with a moisture content of 20-35wt%; (2) Apply the leaching agent to the soil of saline-alkali land; (3) Apply microbial agents through a drip irrigation system after planting crops in the soil; The pre-embedded agent includes at least one of the following: well-rotted organic fertilizer, agglomerant, long-acting functional material and surfactant; the leaching agent includes modified or unmodified polysiloxane; and the surfactant includes C5-C20 sulfonates.

[0007] The second aspect of the present invention provides the application of the method described in the first aspect in the improvement of saline-alkali land.

[0008] The beneficial effects obtained by the present invention through the above technical solution include at least the following: This invention improves soda-saline-alkali land by using specific amendments and methods. It enhances the soil structure and physicochemical properties of saline-alkali land, especially soda-saline-alkali land, by reducing salinity and pH, improving soil aggregate structure, increasing organic matter and humus content, and boosting productivity. It also strengthens crop adaptability and tolerance to adverse environments. Furthermore, it shortens the improvement cycle, reduces the overall cost of large-scale improvement, and improves the stability of the improvement effect. Attached Figure Description

[0009] Figure 1 The seedling stage of maize in untreated, severely saline-alkali soil; Figure 2 This is the corn seedling stage state in Example 1; Figure 3 This is the corn tasseling stage state of Example 1; Figure 4 This is the seedling stage of corn in ratio 6. Detailed Implementation

[0010] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0011] In this invention, C5-C20 sulfonates refer to compounds with 5-20 carbon atoms in their molecules and containing sulfonic acid groups. They may contain other substituents or functional groups, such as halogens or phenyl groups, for example, n-pentane sulfonate, octadecyl sulfonate, methylbenzene sulfonate, dodecylbenzene sulfonate, and tetradecylbenzene sulfonate.

[0012] The first aspect of this invention provides a method for improving saline-alkali land, the method comprising: (1) Bury the pre-embedded agent in the soil of soda saline-alkali land with a moisture content of 20-35wt%; (2) Apply the leaching agent to the soil of saline-alkali land; (3) After planting crops in the soil, apply microbial agents through a drip irrigation system; The pre-embedded agent includes at least one of the following: well-rotted organic fertilizer, agglomerant, long-acting functional material and surfactant; the leaching agent includes modified or unmodified polysiloxane; and the surfactant includes C5-C20 sulfonates.

[0013] In this invention, the use of pre-embedded agents, leaching agents, and microbial agents containing the aforementioned components, along with the methods described above, can improve the soil structure and physicochemical properties of saline-alkali land, especially soda saline-alkali land. This includes reducing the salt and alkali content of the land, improving the soil aggregate structure, increasing the organic matter and humus content, and enhancing the productivity of soda saline-alkali land. Furthermore, it enhances the adaptability and tolerance of crops to adverse environments. Moreover, it can further shorten the saline-alkali land improvement cycle, reduce the overall cost of large-scale improvement, and improve the stability of the improvement effect.

[0014] Specifically, (1) in the pre-embedded agent, decomposed organic fertilizer can improve soil structure, increase large-particle soil aggregates, improve soil porosity and permeability, reduce soil salinity and alkalinity, increase nutrient and organic matter content, increase soil nutrients, optimize soil microbial community structure, promote the production of organic acids by microorganisms, and enhance soil enzyme activity; the hydrolysis of the aggregate can release a large amount of H + This lowers the soil pH, and hydrolysis also forms polymeric ions. One end of these ions can connect with soil mineral colloids through ligand exchange reactions, while the other end connects with humic molecules, creating a "bridge" between organic and inorganic colloids. This enhances the aggregation of soil structures, promotes the transformation of small-sized micro-aggregates into large-sized aggregates, and improves soil structure and permeability. Long-lasting functional materials can be oxidized through chemical and biological processes to produce H+. + (1) It can effectively reduce soil pH; the addition of surfactants can reduce the surface activity between soil particles, which is conducive to the release of water molecules bound between particles during the formation of soil aggregate structure; (2) Leaching agent can ensure rapid penetration of water and rainfall, and promote the speed of salt leaching; (3) Microbial agents increase the stability of soil aggregates through their metabolic activities, thereby improving soil aeration and water retention. At the same time, the strains have nitrogen fixation ability, which can promote plant growth.

[0015] In step (1) of the present invention, preferably, based on the total weight of the pre-embedded agent, the weight of the decomposed organic fertilizer is 70-98wt%, for example, it can be any two values ​​of 70wt%, 71wt%, 73wt%, 75wt%, 77wt%, 79wt%, 70wt%, 80wt%, 85wt%, 87wt%, 89wt%, 90wt%, 92wt%, 94wt%, 98wt% or more, or a value within the range of the above, more preferably 75-79wt%.

[0016] Preferably, the composted organic fertilizer is at least one of composted cow manure, sheep manure, and green manure.

[0017] More preferably, the composted organic fertilizer is composted cow manure and composted sheep manure.

[0018] More preferably, the weight ratio of the composted cow dung to the composted sheep dung is 1:(0.5-2).

[0019] Preferably, based on the total weight of the pre-embedded agent, the weight of the agglomerating agent is 3-20 wt%, for example, it can be any two values ​​of 3 wt%, 5 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 15 wt%, 20 wt%, or more, and values ​​within the range thereof, more preferably 3-15 wt%, and even more preferably 8-13 wt%.

[0020] Preferably, the agglomerating agent includes at least one of potassium aluminum sulfate, polyferric sulfate, polyaluminum chloride, polyaluminum sulfate, and active silica.

[0021] According to a preferred embodiment of the present invention, the number average molecular weight of the polyferric sulfate, polyaluminum chloride, or polyaluminum sulfate can be selected within a wide range, for example, each can be independently 10. 2 -10 6 Da.

[0022] Potassium aluminum sulfate and polyferric sulfate will produce a large amount of H₂ during hydrolysis. + Neutralize OH in the soil - This lowers the soil pH. The aluminum hydroxide colloidal particles generated by the hydrolysis of potassium aluminum sulfate have a large surface area and adsorption capacity, forming large flocs. The polynuclear complexes generated after the hydrolysis of polyferric sulfate, such as [Fe4(H2O)6], [Fe2(H2O)6], and [Fe(OH)2], have strong flocculation capabilities and a wide pH range. These high molecular structures can promote the transformation of small-diameter micro-aggregates into large-diameter aggregates in the soil, thereby improving soil structure and permeability. Furthermore, the inventors of this invention discovered that active silicic acid can synergistically enhance the soil aggregation-improving effect of flocs and polynuclear complexes with potassium aluminum sulfate and polyferric sulfate. Based on the above findings, the preferred agglomerating agent is potassium aluminum sulfate, polyferric sulfate, and active silicic acid.

[0023] According to some specific embodiments of the present invention, the active silicic acid is potassium silicate.

[0024] In this invention, the ratio of potassium aluminum sulfate, polyferric sulfate and active silica can be selected within a wide range. For example, the weight ratio of potassium aluminum sulfate, polyferric sulfate and active silica can be 1:(0.2-3):(0.1-0.5), preferably 1:(1-3):(0.1-0.5), and more preferably 1:(1.5-2.5):(0.35-0.45).

[0025] Preferably, the weight of the long-lasting functional material is 3-20 wt%, based on the total weight of the pre-embedded agent.

[0026] Preferably, the long-lasting functional material includes at least one of sulfur, peat moss, and pine needles.

[0027] In soil, sulfur can be continuously converted into sulfuric acid by oxidizing bacteria, releasing hydrogen ions to neutralize alkaline substances (such as Na₂CO₃ and NaHCO₃) and thus effectively lower the pH value. Pine needles contain specific acidic substances that not only weaken the affinity of soil colloidal particles for water and disrupt the colloidal structure of soil particles, but also synergistically enhance the dissociation of soil colloids by interacting with the hydrolysis products of agglomerators, thereby further improving soil structure.

[0028] More preferably, the long-lasting functional material is sulfur and pine needles.

[0029] Preferably, the weight ratio of sulfur to pine needles is (1-5):1, for example, it can be any two values ​​within the range of 1:1, 2:1, 2.5:1, 3:1, 3.5:1, 5:1 or above, and more preferably (2.5-3.5):1.

[0030] Preferably, based on the total weight of the pre-embedded agent, the weight of the surfactant is 0.1-5 wt%, for example, it can be any two values ​​forming a range or value within the range of 0.1 wt%, 0.2 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.1 wt%, 1.2 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 5 wt%, or more, more preferably 0.5-2 wt%, and even more preferably 0.8-1.2 wt%.

[0031] Preferably, the surfactant comprises at least one of a C10-C12 benzenesulfonate and / or a C14-C16 sulfonate.

[0032] More preferably, the surfactant is a C10-C12 benzenesulfonate, and even more preferably a dodecylbenzenesulfonate.

[0033] According to a preferred embodiment of the present invention, the cationic group in the surfactant can be a common cation found in soil, such as at least one of sodium ion, potassium ion, calcium ion, and magnesium ion. According to some specific embodiments of the present invention, the cationic group in the surfactant is sodium ion.

[0034] In step (2) of the present invention, preferably, the rinsing agent further includes polyglutamic acid.

[0035] Polyglutamic acid molecules contain numerous carboxyl groups and peptide bonds in their main chain, allowing them to directly interact with alkaline substances to lower soil pH, significantly improve water wettability, accelerate water and fertilizer infiltration, and rapidly migrate topsoil salts to deeper soil layers, thus quickly reducing salinity. Therefore, as a leaching agent, it is applied to the soil after pre-embedded fertilizers and before planting crops to promote salt removal. Furthermore, polyglutamic acid can significantly improve the photosynthetic efficiency and stress resistance (such as drought, salt, and disease resistance) of plants during crop growth stages, and further promote root development and enhance root absorption capacity.

[0036] More preferably, the weight ratio of the modified or unmodified polysiloxane to polyglutamic acid is (0.2-5):1, further preferably (1-3):1, and particularly preferably (1.5-2.5):1.

[0037] Preferably, the modified polysiloxane is a polysiloxane, more preferably a polydimethylsiloxane.

[0038] According to a preferred embodiment of the present invention, in order to improve the efficiency of soil improvement and promote crop growth, it is preferable to dilute the leaching agent before applying it to the soil. The dilution ratio can be flexibly adjusted according to the actual situation, for example, it can be diluted to 100-300 times, preferably 180-220 times.

[0039] Preferably, the microbial agent comprises microorganisms and / or extracellular polysaccharides.

[0040] According to a preferred embodiment of the present invention, the microorganism may be Bacillus subtilis (Bacillus subtilis). Bacillus subtilis ), Bacillus megaterium (Bacillus megaterium) ), gelatinous spore-forming bacteria ( Paenibacillus mucilaginosus At least one of the following, preferably Bacillus subtilis, Bacillus megaterium, and gelatinous Bacillus.

[0041] According to some specific embodiments of the present invention, Bacillus subtilis is designated as CGMCC 1.286, Bacillus megaterium as CGMCC 1.6721, and Bacillus jellyoides as CGMCC 1.232.

[0042] Extracellular polysaccharides not only promote the formation of large soil aggregates, effectively improving soil structure and enhancing soil aeration and water retention, but also possess significant growth-promoting, immune-inducing, and stress-mitigating functions. Through a triple mechanism of physical, biochemical, and ecological action, they comprehensively promote crop growth and enhance stress resistance. According to a preferred embodiment of the present invention, the extracellular polysaccharide can be a water-soluble polysaccharide produced by microbial metabolism, such as xanthan gum, gellan gum, trehalose, or hyaluronic acid, preferably xanthan gum.

[0043] Preferably, the microbial agent comprises microorganisms and extracellular polysaccharides, wherein the viable count of the microorganisms is 10 per gram of extracellular polysaccharides. 8 -10 13 CFU, for example, can be 10. 8 CFU, 10 9 CFU, 10 10 CFU, 10 11 CFU, 10 12 CFU, 10 13 The range formed by any two values ​​of CFU or above, and the value within that range, is more preferably 10. 10 -10 12 CFU.

[0044] Preferably, relative to a surface area of ​​1000m² 2 The total weight of the soil, pre-embedded agent, leaching agent and microbial agent is 5-20 tons, more preferably 5-10 tons, and even more preferably 8-10 tons.

[0045] In this invention, the relevant amounts of the microbial agent (such as the content of each component, the dosage, etc.) are all calculated based on the weight of the liquid agent.

[0046] In this invention, when applying microbial agents through a drip irrigation system, the drip irrigation system "creates" and maintains a root zone microenvironment with sufficient moisture and continuous salt leaching by precisely supplying water to specific points. While exerting the efficacy of the microbial agents, it also utilizes the laws of water and salt movement to "drive away" and "lock" harmful salts in specific areas that are difficult for crop roots to reach.

[0047] In this invention, during the process of improving saline-alkali land, the crops can be salt-tolerant crops such as corn, wheat, cotton, and sunflower. However, the inventors of this invention have discovered through research that, compared to other common crops, corn possesses salt tolerance and a well-developed root system. Furthermore, its root exudates can regulate the rhizosphere pH and control stomatal opening and closing to maintain plant physiological balance. Simultaneously, it accumulates osmotic-regulating substances such as proline. These excellent physiological properties allow the root system to further synergistically work with the pre-embedded agent, leaching agent, and microbial agent provided by this invention during its growth process, thereby effectively improving soil permeability.

[0048] Furthermore, corn can serve as an indicator crop for improving saline-alkali land. If the improved soil can support the normal growth of corn, it directly demonstrates the significant improvement effect of saline-alkali land. Planting other crops on this basis usually also ensures normal growth, achieving the goal of cultivating high-quality soil suitable for multiple crops with a single improvement.

[0049] Preferably, the method further includes: applying the pre-embedding agent to the topsoil before burying it in the soil of saline-alkali land.

[0050] The second aspect of the present invention provides the application of the method described in the first aspect in the improvement of saline-alkali land.

[0051] The present invention will be described in detail below through embodiments. It should be understood that the following embodiments are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0052] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available products purchased from regular chemical or biological reagent / material suppliers, and all reagents are of analytical grade.

[0053] Bacillus subtilis ( Bacillus subtilis CGMCC 1.286, Bacillus megaterium ( Bacillus megatherium CGMCC 1.6721, Bacillus jellyoidus ( Paenibacillus mucilaginosus CGMCC1.232, all purchased from the China General Microbiological Culture Collection Center; Extracellular polysaccharides: The main component is xanthan gum; Well-rotted organic fertilizer: Cow manure and sheep manure in a 1:1 weight ratio, composted using conventional methods. After composting, the color is dark brown to black, with no obvious ammonia or foul odor, moisture content of 35±5%, C / N ≤20:1, and seed germination index ≥70%. Polyferric sulfate: number average molecular weight 399.88 g / mol; Active silicic acid: liquid potassium silicate; Pine needles: sourced from the Changbai Mountain region of Jilin Province; Polydimethylsiloxane (unmodified polysiloxane), CAS No. 68937-54-2, number average molecular weight 5600 Da, purchased from Guangzhou Huazhiwang Chemical Co., Ltd., product number KF-6017; Polyglutamic acid: CAS No. 25513-46-6, number average molecular weight 50-200 kDa, purchased from Shandong Jingwei Chemical Co., Ltd., item number 09; Test method: The soil permeability coefficient was tested using the ring sampler method (F-HZ-DZ-TR-0021). Uncirculated soil samples were taken using a ring sampler, and after immersion in water, the water flow velocity per unit soil cross-sectional area perpendicular to the water flow direction was calculated according to Darcy's law under a unit water pressure gradient. This velocity is the soil permeability coefficient.

[0054] The soil bulk density test method adopts the ring cutter method (NY / T1121.4-2006). The soil sample in its natural state is cut with a ring cutter of a certain volume to fill the sample. The mass of the dried soil sample per unit volume is then calculated, which is the bulk density.

[0055] Soil pH was determined using the point method (HJ 962-2018), with water as the extractant and a water-to-soil ratio of 2.5:1. When the indicator electrode and reference electrode were immersed in the soil suspension, a galvanic cell was formed. At a certain temperature (25℃), its electromotive force was related to the pH of the suspension. The soil pH could be obtained by measuring the electromotive force of the galvanic cell.

[0056] The total salt content of soil was determined by chemical analysis (GB 15618-2018), which involved water extraction, evaporation, drying and weighing of soil samples.

[0057] Soil organic matter content was determined using the potassium dichromate titration method (NY-T 1121.6-2006). Under acidic conditions, excess potassium dichromate was used to oxidize soil organic carbon, and the organic carbon content was calculated by titrating the unreacted potassium dichromate, thereby obtaining the soil organic matter content.

[0058] Soil Moisture Content Test Method (HJ 613-2011): Soil samples are dried to constant weight at (105±5)℃. The dry matter and moisture content are calculated based on the difference in soil sample mass before and after drying, and labeled as mass fraction.

[0059] The average soil pH is 10.22, indicating a predominantly alkaline soil condition, with many sampling points showing strongly alkaline or even extremely strongly alkaline soil. The average total salt content is 0.93%, with a maximum of 2.77%. The average organic matter content is 11.63 g / kg, and the soil has extremely poor permeability, making it impossible for crops to grow.

[0060] The formula for calculating the surviving rate is: (Number of surviving plants / Number of seedlings) × 100%. To clearly verify the universality of the method provided by this invention, the experiment was designed as follows: Various properties of the land to be improved were pre-tested and recorded, with severely saline-alkali land used as the basic experimental subject for parallel experiments. Based on this, the most effective method was used to further test the soils of moderately and slightly saline-alkali land, thereby comprehensively demonstrating the practical application effect of the method provided by this invention.

[0061] Preparation of microbial agents: Culture medium: molasses 30g / L, corn starch 20g / L, etc.; Nitrogen source: soybean meal powder 15g / L, peanut meal powder 5g / L, fish meal 10g / L, yeast powder 5g / L, peptone 20g / L, ammonium sulfate 5g / L, ammonium chloride 2g / L; Inorganic salts: magnesium sulfate heptahydrate 1g / L, manganese sulfate monohydrate 0.05g / L, dipotassium hydrogen phosphate 5g / L, potassium dihydrogen phosphate 2g / L, calcium carbonate 8g / L), with the remainder being water.

[0062] Bacillus, Bacillus megaterium, and Bacillus mucilaginosus were added to the culture medium and fermented under the following conditions (inoculum size: 10 vol%, temperature: 33 ± 3°C; pH: 7.1 ± 0.3; aeration rate: 1.1 ± 0.3 vvm) until the viable count in the fermentation broth reached 10. 10 Fermentation should be stopped when CFU / g is reached.

[0063] Example 1 (a) Composition of the modifier: (1) Embedded agent: 76 wt% well-rotted organic fertilizer; The agglomerating agent is 10.8 wt%, wherein the weight ratio of potassium aluminum sulfate, polyferric sulfate and active silica is 1:2:0.4. Long-lasting functional materials comprise 10.8 wt%, of which sulfur and pine needles are present in a mass ratio of 3:1. Surfactant 1 wt%, sodium dodecylbenzenesulfonate.

[0064] (2) 1 wt% rinsing agent: polydimethylsiloxane and polyglutamic acid in a weight ratio of 2:1, concentration 0.5 wt%; (3) Microbial inoculant 0.4wt%: Bacillus, Bacillus megaterium, gelatinous Bacillus and extracellular polysaccharide in a mass ratio of 1:4:2:0.5; The total weight of the pre-embedded agent, rinsing agent, and microbial agent is 60 tons.

[0065] (II) Improvement process: (1) After mixing the pre-embedding agent evenly, apply it to a 6666m area. 2 Soil surface (soil moisture content at this time is 27±2wt%); when the soil moisture content is 25wt%, the soil is tilled to a depth of 20cm, and the pre-embedded agent is evenly mixed into the topsoil. (2) Spray 12 tons of leaching agent evenly onto the tilled land; (3) Sow corn at a density of 10 seedlings / m² 2 After sowing, during the first drip irrigation seedling stage, add 240 kg of 0.4 wt% microbial agent to the drip irrigation system, diluted 200 times, and let it enter the ground with the drip irrigation.

[0066] (4) After the corn grows to the three-leaf stage, no more microbial agents are added, the improvement is completed, and the soil physicochemical indicators are tested after the corn matures.

[0067] Example 2 The soil was improved according to the method in Example 1, except that: (1) The mass fractions of decomposed organic fertilizer, aggregates, long-acting functional materials and surfactants were 88 wt%, 5 wt%, 5 wt%, and 0.8 wt%, respectively; (2) The mass fraction of the rinsing agent is 0.8 wt%.

[0068] Example 3 The soil was improved according to the method in Example 1, except that: (1) The mass fractions of decomposed organic fertilizer, agglomerates, long-acting functional materials and surfactants were 70wt%, 12.75wt%, 12.75wt%, and 2wt%, respectively. (2) The mass fraction of the rinsing agent is 2 wt%; (3) The mass fraction of the microbial agent is 0.5 wt%.

[0069] Example 4 The soil was improved according to the method in Example 1, except that: (1) The mass fractions of decomposed organic fertilizer, agglomerates, long-acting functional materials and surfactants were 93.75 wt%, 3 wt%, 3 wt%, and 0.1 wt%, respectively. (2) The mass fraction of the rinsing agent is 0.1 wt%; (3) The mass fraction of the microbial agent is 0.05 wt%.

[0070] Example 5 The soil was improved according to the method in Example 1, except that polydimethylsiloxane was replaced with an equal weight of polyether-modified polydimethylsiloxane, purchased from Guangdong Zhongke Hongtai New Materials Co., Ltd., product number polyether-modified silicone oil (CN-164), with a number average molecular weight of 5600 Da.

[0071] Example 6 The soil was improved according to the method in Example 1, except that the weight ratio of polydimethylsiloxane to polyglutamic acid was 5:1.

[0072] Example 7 The soil was improved according to the method in Example 1, except that the weight ratio of polydimethylsiloxane to polyglutamic acid was 0.2:1.

[0073] Examples 8-9 The soil was improved according to the method in Example 1, except that the soil properties were different, referred to as slightly saline-alkali land and moderately saline-alkali land.

[0074] Comparative Example 1 The soil was improved according to the method of Example 1, except that in step (1), the pre-embedded agent was only well-rotted organic fertilizer, and the amount was 45.6 tons.

[0075] Comparative Example 2 The soil was improved according to the method of Example 1, except that in step (3), the leaching agent was replaced with an equal weight of ethylenediaminetetraacetic acid (EDTA).

[0076] Comparative Example 3 The soil was improved according to the method of Example 1, except that in step (4), the mixed bacterial agent did not contain extracellular polysaccharides, and the total weight of the mixed bacterial agent and the proportion of each component were the same as in Example 1.

[0077] Comparative Example 4 The soil was treated according to the method of Example 1, except that in step (3), the leaching agent did not contain polydimethylsiloxane, and the weight of polyglutamic acid was three times that of Example 1.

[0078] Comparative Example 5 The soil was improved according to the method of Example 1, except that in step (3), the leaching agent did not contain surfactant.

[0079] Comparative Example 6 The soil was improved according to the method in Example 1, except that the pre-embedded agent was replaced with an equal weight of conventional amendment (desulfurized gypsum + humic acid, weight ratio 1:0.1), while the other operations remained unchanged. The desulfurized gypsum was sourced from Hebei Yousheng Refractory Materials Co., Ltd., product number 1030; the humic acid was sourced from Lingshou County Yuede Mineral Products Processing Plant, product number YD-387.

[0080] Comparative Example 7 The soil was improved according to the method of Example 1, except that the pre-embedding agent, leaching agent and microbial agent were mixed and buried in the soil in step (1), and in steps (2) and (3) the leaching agent and microbial agent were replaced with an equal weight of solvent (water).

[0081] Test Example 1 The parameters of the soil before improvement (severely saline-alkali land, slightly saline-alkali land, and moderately saline-alkali land) and the improved soil of the examples and comparative examples are shown in Table 1.

[0082] Table 1

[0083] Among them, the state of severely saline-alkali soil before improvement is as follows: Figure 1 As shown, the improved planting effects of Example 1 and Comparative Example 6 are respectively as follows: Figures 2-3 (Example 1) and Figure 4 As shown in Comparative Example 6, combined with the results in Table 1, it can be seen that after the soil was improved by the improvement method provided by this invention, the permeability was significantly improved, the soil bulk density, pH value and total salt content were significantly reduced, the organic matter content was increased, and the corn plant rate reached about 90%.

[0084] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for improving saline-alkali land, characterized in that, The method includes: (1) Bury the pre-embedded agent in the soil of soda saline-alkali land with a moisture content of 20-35wt%; (2) Apply the leaching agent to the soil of saline-alkali land; (3) After planting crops in the soil, apply microbial agents through a drip irrigation system; The pre-embedded agent includes at least one of the following: well-rotted organic fertilizer, agglomerant, long-acting functional material and surfactant; the leaching agent includes modified or unmodified polysiloxane; and the surfactant includes C5-C20 sulfonates.

2. The method according to claim 1, wherein, The decomposed organic fertilizer is at least one of the following: composted cow manure, sheep manure, and green manure; And / or, the agglomerating agent includes at least one of potassium aluminum sulfate, polyferric sulfate, polyaluminum chloride, polyaluminum sulfate, and active silica. And / or, the long-lasting functional material includes at least one of sulfur, peat moss and pine needles; And / or, the surfactant includes at least one of a C10-C12 benzenesulfonate and / or a C14-C16 sulfonate.

3. The method according to claim 1, wherein, The composted organic fertilizer is composted cow manure and composted sheep manure; And / or, the agglomerating agent is potassium aluminum sulfate, polyferric sulfate, and active silica; And / or, the number-average molecular weights of the polyferric sulfate, polyaluminum chloride, and polyaluminum sulfate are each independently 10. 2 -10 6 Da; And / or, the long-lasting functional material is sulfur and pine needles; And / or, the surfactant is a C10-C12 benzenesulfonate.

4. The method according to claim 3, wherein, The weight ratio of the composted cow dung to the composted sheep dung is 1:(0.5-2). And / or, the weight ratio of potassium aluminum sulfate, polyferric sulfate and active silica is 1:(0.2-3):(0.1-0.5); And / or, the weight ratio of sulfur to pine needles is (1-5):

1.

5. The method according to claim 1, wherein, Based on the total weight of the pre-embedded agent, the weight of the well-rotted organic fertilizer is 70-98 wt%. And / or, based on the total weight of the pre-embedded agent, the weight of the agglomerating agent is 3-20 wt%; And / or, based on the total weight of the pre-embedded agent, the weight of the long-lasting functional material is 3-20 wt%; And / or, based on the total weight of the pre-embedded agent, the weight of the surfactant is 0.1-5 wt%.

6. The method according to claim 1, wherein, The modified polysiloxane is a polysiloxane; And / or, the rinsing agent further includes polyglutamic acid; And / or, the microbial agent includes microorganisms and / or extracellular polysaccharides.

7. The method according to claim 6, wherein, The microbial inoculant comprises microorganisms and extracellular polysaccharides, wherein the viable count of the microorganisms is 10 per gram of extracellular polysaccharides. 8 -10 13 CFU; And / or, the weight ratio of the modified or unmodified polysiloxane to polyglutamic acid is (0.2-5):

1.

8. The method according to claim 1, wherein, Relative to a surface area of ​​1000m² 2 The total weight of the soil, pre-embedded agent, leaching agent and microbial agent is 5-20 tons; And / or, the weight ratio of the pre-embedding agent, the rinsing agent and the microbial agent is (150-2500):(1-10):

1.

9. The method according to claim 7, wherein, The method further includes: applying the pre-embedding agent to the topsoil before burying it in the soil of saline-alkali land.

10. The application of the method according to any one of claims 1-9 in the improvement of saline-alkali land.

Images