Soil saline-alkali modifier as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of soil improvement, and relates to a soil saline-alkali improver as well as a preparation method and application thereof. The invention provides a soil saline-alkali modifier. The soil saline-alkali modifier is composed of a shell slow-release layer, a middle conditioning layer and an internal functional layer, the internal functional layer is prepared from a saline-alkali soil improving fungicide, biochar and a granulation adhesive; the middle conditioning layer is composed of a conditioner, a first slow-release agent and a first solvent; the shell slow-release layer is prepared from humic acid, furfural residues, a calcium ion compound, a second slow-release agent and a second solvent; the calcium ion compound is at least one of phosphogypsum, desulfurized gypsum, calcium chloride and calcium sulfate; the conditioner is at least one of coumarin, resveratrol and catechin. A multi-layer slow-release structure is constructed, through a multi-layer slow-release mode, all the improvement components make contact with the saline-alkali soil in sequence, and the excellent improvement effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of soil improvement, and relates to a soil saline-alkali improver and a preparation method and application thereof. Background Art

[0002] In agricultural production, soil salinization is a global environmental problem that seriously affects the growth and yield of crops and limits the sustainable use of agricultural resources. Saline-alkali soils usually contain high concentrations of soluble salts (such as sodium chloride, sodium sulfate, etc.) and excessive alkaline substances (such as sodium carbonate, sodium bicarbonate, etc.). These components not only lead to reduced soil permeability and reduced water retention capacity, but also directly affect the absorption and utilization of nutrients by plants, thereby causing plant physiological disorders such as ion poisoning, nutritional imbalance and growth inhibition. Traditional methods for improving soil salinity mainly include water conservancy improvement (such as irrigation and drainage), physical improvement (such as soil transfer method, deep tillage and loosening soil) and chemical improvement (such as application of gypsum, gypsum-superphosphate, etc.). However, these methods often have shortcomings such as high cost, short-term effects or the introduction of new environmental problems. In particular, chemical amendments, although they can reduce soil salinity to a certain extent, often lack specificity, and the improvement effect is easily affected by environmental conditions and difficult to maintain for a long time.

[0003] In recent years, with the rapid development of biotechnology and materials science, the research on improving saline-alkali soil using new materials such as microbial agents and biochar has gradually increased. Microbial agents can improve soil structure, promote nutrient circulation, and increase soil fertility by secreting organic acids, enzymes and other substances; while biochar, due to its porosity, high specific surface area and rich functional groups, can adsorb and fix harmful ions in the soil, while improving the physical and chemical properties of the soil. For example, CN110846249A discloses a microorganism, a microbial agent and a saline-alkali soil microbial improver that can be used to improve saline-alkali soil. The microorganism and the microbial agent that can be used to improve saline-alkali soil are made into saline-alkali soil microbial improvers and applied to saline-alkali land to improve soil fertility, retain fertilizer and water, reduce pests and diseases, reduce soil salinity and pH, and play a positive role in saline-alkali soil improvement; CN115746864A discloses a biochar-based soil improver for coastal saline-alkali land and a preparation method thereof. The biochar-based soil improver is prepared by mixing a specific amount of modified biochar material, desulfurized gypsum, fulvic acid chelated iron and amino acid-modified polyacrylamide, and is applied to coastal saline-alkali land. The synergistic combination of the above raw materials not only effectively reduces the pH, salt content and bulk density of the saline-alkali soil, but also improves the aeration and water retention performance of the soil, and can also provide nutrients, improve the soil aggregate structure, and thus increase the yield of crops planted on the saline-alkali land. However, simply combining these materials directly ignores the actual effects of each component and often makes it difficult to achieve the desired improvement effect. In addition, the effect is easily restricted by environmental conditions and is difficult to sustain. Summary of the invention

[0004] In order to overcome the above technical problems, the present invention has developed a soil salinity-alkali improver that can integrate multiple improvement mechanisms and has long-term slow-release characteristics. The soil salinity-alkali improver provided by the present invention can realize the precise control and release of different improvement components by constructing a multi-layer slow-release structure, so that they can contact the saline-alkali soil in sequence at different stages, thereby more efficiently exerting their respective improvement effects and improving the overall effect of soil improvement.

[0005] On the one hand, the present invention relates to a soil salinity-alkali conditioner, which is composed of an outer shell slow-release layer, a middle conditioning layer and an inner functional layer;

[0006] The internal functional layer is a saline-alkali land improving bacterial agent, biochar and a granulation binder;

[0007] The middle conditioning layer is composed of a conditioning agent, a first sustained-release agent and a first solvent;

[0008] The shell sustained-release layer is composed of humic acid, furfural residue, calcium ion compound, a second sustained-release agent and a second solvent;

[0009] The calcium ion compound is at least one of phosphogypsum, desulfurized gypsum, calcium chloride and calcium sulfate;

[0010] The conditioning agent is at least one of coumarin, resveratrol and catechins.

[0011] Furthermore, in the soil salinity-alkali conditioner provided by the present invention, the biochar is fruit shell biochar or straw biochar.

[0012] Furthermore, in the soil saline-alkali conditioner provided by the present invention, the composition of the granulation adhesive is, by mass percentage, 0.1-5% of thickener, 0.01-10% of tackifier, 1-5% of stabilizer, and the balance is water.

[0013] Furthermore, in the soil salinity-alkali improver provided by the present invention, the stabilizer is selected from at least one of carboxymethyl cellulose, water-soluble biopolysaccharides, sodium alginate, and sodium polyacrylate;

[0014] The thickener is selected from at least one of gelatin, xanthan gum, sodium alginate and agar;

[0015] The tackifier is selected from at least one of polyvinyl alcohol, polyethylene glycol and polyacrylamide.

[0016] Furthermore, in the soil salinity-alkali conditioner provided by the present invention, the first slow-release agent or the second slow-release agent is independently selected from at least one of gelatin, xanthan gum, sodium alginate, and agar;

[0017] The first solvent and the second solvent are water.

[0018] In another aspect, the present invention relates to a method for preparing a soil salinity-alkali conditioner, comprising the following steps:

[0019] Step 1: after uniformly mixing the saline-alkali land improving bacterial agent and the biochar, the mixture is mixed with the granulation binder for granulation to obtain an inner core as the inner functional layer;

[0020] Step 2: mixing and stirring the conditioning agent, the first sustained-release agent and the first solvent to prepare a first suspension;

[0021] Step 3: mixing the inner core and the first suspension, granulating and drying to obtain a semi-finished product;

[0022] Step 4: mixing and stirring humic acid, furfural residue, the calcium ion compound, the second sustained-release agent and the second solvent to obtain a second suspension;

[0023] Step 5: Mix the semi-finished product and the second suspension, granulate and then dry to obtain the soil salinity-alkali conditioner.

[0024] Furthermore, in the preparation method provided by the present invention, the mass ratio of the saline-alkali land improving bacterial agent to the biochar is 30-50:10-15;

[0025] In terms of mass percentage, the granulation binder is 1 to 3% of the sum of the mass of the saline-alkali land improving bacterial agent and the biochar;

[0026] The mass ratio of the conditioning agent, the first sustained-release agent and the first solvent is 30-50:1-5:100;

[0027] The mass ratio of the humic acid, the furfural residue, the calcium ion compound, the second sustained-release agent and the second solvent is 10-15:10-15:20-30:1-5:100.

[0028] Furthermore, in the preparation method provided by the present invention, the particle size of the inner core is 4 to 6 mm, the particle size of the semi-finished product is 1 to 2 mm larger than the particle size of the inner core, and the particle size of the soil salinity-alkali conditioner is 2 to 4 mm larger than the particle size of the semi-finished product.

[0029] On the other hand, the present invention relates to the use of the soil salinity-alkali improver, or the soil salinity-alkali improver prepared by the preparation method, in improving saline-alkali soil.

[0030] Furthermore, in the application provided by the present invention, it is used for at least one of increasing crop yield, reducing hydrogen peroxide content in crops, reducing superoxide anion levels in crops, reducing pH of saline-alkali soil, and reducing salt content of saline-alkali soil.

[0031] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0032] (1) The soil salinity improver adopts a multi-layer slow-release design to ensure that each improved component can contact the saline-alkali soil in a predetermined order and rate, avoiding the problem of uneven component release and short-lasting effect in traditional improvement methods. The outer shell slow-release layer acts first, effectively reducing the soil salt concentration and pH value, laying the foundation for the in-depth effect of subsequent improved components; the middle conditioning layer further enhances the plant's resistance to salt stress and improves the survival ability of crops in harsh environments; the internal functional layer deeply improves the soil structure, improves soil fertility, and builds a fertile and desalinated soil layer through the synergistic effect of biochar and improved bacteria, thereby significantly improving the overall soil improvement effect.

[0033] (2) The humic acid and furfural residue in the shell slow-release layer can improve the soil aggregation structure, loosen the topsoil, and effectively eliminate the soil compaction phenomenon. This not only improves the air permeability and water and fertilizer retention capacity of the soil, but also promotes the growth and development of plant roots, providing a more favorable soil environment for crop growth. Through the multi-layer slow-release structure, the nutrients in the soil salinity-alkali improver can be gradually released into the soil, reducing the loss and waste of nutrients. At the same time, the calcium ion compounds and other ingredients in the soil salinity-alkali improver can also react with other ions in the soil to form stable compounds, further improving the utilization efficiency of nutrients. Conditioning agents such as coumarin, resveratrol, and catechins in the middle conditioning layer can significantly improve the salt stress resistance of plants, allowing crops to grow normally in a high-salt environment. This is of great significance for agricultural production in saline-alkali areas and can significantly improve the yield and quality of crops. The combined action of the salinity-alkali land improvement agent and biochar in the internal functional layer not only provides a good environment for the growth of microorganisms, but also promotes the diversity and ecological balance of soil microbial populations. Microorganisms play an important role in soil improvement. They can decompose organic matter, release nutrients, inhibit pathogens, etc., thereby further improving the soil environment.

[0034] (3) The soil salinity improver is made of natural or renewable raw materials, such as humic acid, furfural residue, biochar, etc. It is not only widely available and low-cost, but also does not cause secondary pollution to the environment during use. At the same time, its multi-layer slow-release structure also ensures the durability of the improvement effect, reduces the amount and frequency of soil salinity improver use, and meets the requirements of environmental protection and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 This is a field map before saline-alkali soil improvement.

[0037] Figure 2 Field map of improved saline-alkali soil DETAILED DESCRIPTION

[0038] The technical scheme of the present invention is described below in conjunction with the examples, but the present invention is not limited to the following examples. The experimental methods and detection methods described in each example are conventional methods unless otherwise specified; the reagents and materials are available on the market unless otherwise specified, and the % in the following examples are all mass percentages unless otherwise specified.

[0039] The following saline-alkali land improvement agents are all composite salt-tolerant microbial agents (containing Bacillus subtilis and other beneficial microorganisms, 5×10 8 CFU / mL) was purchased from Beijing Bennong Technology Development Co., Ltd.

[0040] Straw biochar (corn straw, 200 mesh) and husk biochar (coconut shell, 200 mesh) were purchased from Henan Xingnuo Environmental Protection Materials Co., Ltd.

[0041] Example 1

[0042] This embodiment provides the preparation of a soil salinity-alkali conditioner.

[0043] Step 1: According to the formula, take 0.1% gelatin, 0.01% polyvinyl alcohol, 1% carboxymethyl cellulose, and the rest is water, totaling 100%. Pour water into the mixing tank, add thickener and stabilizer first, stir for 30 minutes until completely dissolved, then add viscosity enhancer, continue stirring for 45 minutes, until the viscosity enhancer is completely dissolved, and can be loaded into the tank to obtain granulation adhesive. During the entire stirring process, the stirring speed should not be too fast, and the stirring speed should be controlled within the range of 300-500r / min. Stirring too fast will produce too much foam that is not easy to dissipate, and stirring too slowly will cause part of the viscosity enhancer to dissolve and disperse unevenly, which will bring difficulties to use.

[0044] Step 2: Take the saline-alkali land improving bacteria agent and the straw biochar in a mass ratio of 30:10, mix the saline-alkali land improving bacteria agent and the biochar evenly in a stirring tank, then add 1% of a granulation adhesive, mix evenly, and use a fluidized bed granulator to granulate to obtain a 4 mm inner core.

[0045] Step 3: Mix and stir coumarin, gelatin and water in a mass ratio of 30:1:100 to prepare a first suspension.

[0046] Step 4: After the first suspension and the inner core are evenly mixed, granulation is performed using a fluidized bed granulator, and drying is performed at room temperature to obtain a 5 mm semi-finished product.

[0047] Step 5: Mix and stir humic acid, furfural residue, phosphogypsum, gelatin and water in a mass ratio of 10:10:20:1:100 to obtain a second suspension.

[0048] Step 6: After the second suspension and the semi-finished product are evenly mixed, the mixture is granulated using a fluidized bed granulator, and dried at room temperature to obtain a 7 mm soil salinity improver.

[0049] Example 2

[0050] This embodiment provides the preparation of a soil salinity-alkali conditioner.

[0051] Step 1: According to the formula, take 1% xanthan gum, 1% agar, 3% polyethylene glycol, 2% water-soluble biopolysaccharide (starch), and the balance is water, totaling 100%. Pour water into the mixing tank, add thickener and stabilizer first, stir for 30 minutes until completely dissolved, then add viscosity enhancer, continue stirring for 45 minutes, until the viscosity enhancer is completely dissolved, and can be loaded into the tank to obtain a granulation adhesive. During the entire stirring process, the stirring speed should not be too fast, and the stirring speed should be controlled to 300-500r / min. Stirring too fast will produce too much foam that is not easy to dissipate, and stirring too slowly will cause part of the viscosity enhancer to dissolve and disperse unevenly, which will bring difficulties to use.

[0052] Step 2: Take the saline-alkali land improving bacteria agent and the fruit shell biochar in a mass ratio of 40:13, mix the saline-alkali land improving bacteria agent and the biochar evenly in a stirring tank, then add 2% of a granulation binder, mix evenly, and use a fluidized bed granulator to granulate to obtain a 5 mm inner core.

[0053] Step 3: resveratrol, xanthan gum and water are mixed and stirred in a mass ratio of 40:3:100 to prepare a first suspension.

[0054] Step 4: After the first suspension and the inner core are evenly mixed, granulation is performed using a fluidized bed granulator, and drying is performed at room temperature to obtain a 6 mm semi-finished product.

[0055] Step 5: Mix and stir humic acid, furfural residue, desulfurized gypsum, xanthan gum and water in a mass ratio of 12:12:25:3:100 to obtain a second suspension.

[0056] Step 6: After the second suspension and the semi-finished product are evenly mixed, the mixture is granulated using a fluidized bed granulator, and dried at room temperature to obtain a 9 mm soil salinity-alkali conditioner.

[0057] Example 3

[0058] This embodiment provides the preparation of a soil salinity-alkali conditioner.

[0059] Step 1: According to the formula, take 5% sodium alginate, 5% polyacrylamide, 5% sodium polyacrylate, and the rest is water, totaling 100%. Pour water into the mixing tank, add thickener and stabilizer first, stir for 30 minutes until completely dissolved, then add tackifier, continue stirring for 45 minutes, until the tackifier is completely dissolved, and can be loaded into the tank to obtain granulation adhesive. During the entire stirring process, the stirring speed should not be too fast, and the stirring speed should be controlled at 300-500r / min. Stirring too fast will produce too much foam that is not easy to dissipate, and stirring too slowly will cause part of the tackifier to dissolve and disperse unevenly, which will bring difficulties to use.

[0060] Step 2: Take the saline-alkali land improving bacteria agent and the fruit shell biochar in a mass ratio of 50:15, mix the saline-alkali land improving bacteria agent and the biochar evenly in a stirring tank, then add 3% of a granulation binder, mix evenly, and use a fluidized bed granulator to granulate to obtain a 6 mm inner core.

[0061] Step 3: Mix and stir catechin, sodium alginate and water in a mass ratio of 40:3:100 to prepare a first suspension.

[0062] Step 4: After the first suspension and the inner core are evenly mixed, granulation is performed using a fluidized bed granulator, and drying is performed at room temperature to obtain a 8 mm semi-finished product.

[0063] Step 5: Mix and stir humic acid, furfural residue, calcium chloride, calcium sulfate, sodium alginate and water in a mass ratio of 15:15:15:15:5:100 to obtain a second suspension.

[0064] Step 6: After the second suspension and the semi-finished product are evenly mixed, the mixture is granulated using a fluidized bed granulator, and then dried at room temperature to obtain a 12 mm soil salinity improver.

[0065] Comparative Example 1

[0066] This comparative example 1 is intended to illustrate the effects of the structure provided by the present invention by comparison. Its preparation method is the same as that of Example 1, except that the inner core and the second suspension are first made into a semi-finished product, and then the semi-finished product and the first suspension are made into a soil salinity-alkali conditioner.

[0067] Comparative Example 2

[0068] This comparative example 1 is intended to illustrate the effects of the structure provided by the present invention by comparison. Its preparation method is the same as that of Example 1, except that the first suspension and the second suspension are mixed in a mass ratio of 1:2, and then prepared into a soil salinity-alkali conditioner with the inner core.

[0069] Comparative Example 3

[0070] This comparative example is the inner core prepared in Example 1.

[0071] Test Case

[0072] This test example provides the application effect of soil salinity and alkali amendment.

[0073] The test site is a heavily saline-alkali field in the Xinjiang Uygur Autonomous Region test base. The original soil has a pH of 8.8-9.2 and a salt content of 6.6-7.0 g / kg. The soil salinity modifiers prepared in Examples 1-3 and Comparative Examples 1-3 are applied to the soil at an amount of 70.0 kg / mu, and then quinoa is planted. The field management measures are local unified conventional management. After quinoa is harvested, the change in soil salinity is characterized by measuring the soil pH and salt content of each group, as well as the growth of quinoa. Five measurement points are randomly selected for each group, and the improvement effect is determined by the average value obtained. The statistical results are shown in Table 1.

[0074] Table 1: Soil changes and improvement effects

[0075]

[0076] As can be seen from Table 1, the soil salinity improvers used in Examples 1 to 3 have achieved remarkable results in improving the soil conditions of the severely saline-alkali land in the experimental base of Xinjiang Uygur Autonomous Region. Compared with the pH value (8.8-9.2) and salt content (6.6-7.0 g / kg) of the original soil, the pH value of the soil after treatment in the examples was significantly reduced to 8.01-8.24, and the salt content was also greatly reduced to 2.62-2.89 g / kg, indicating that these soil salinity improvers effectively reduced the alkalinity and salt content of the soil, creating a more favorable environment for crop growth. At the same time, from the perspective of crop growth, the quinoa emergence rate (90.61%-92.52%) and yield (216-230 kg / hm2) of the quinoa treatment group in the examples were significantly reduced to 8.01-8.24, and the salt content was also significantly reduced to 2.62-2.89 g / kg. 2 ) were significantly higher than the control group (germination rate 82.96% to 89.98%, yield 176 to 194 kg / hm 2 ) and blank control group (germination rate 68.12%, yield 113kg / hm 2 ). In addition, the disease rate of the example treatment group is also relatively low (5% to 8%), which further proves that the improvement of the soil environment by these amendments is conducive to the healthy growth of crops and the increase of yield. In contrast, although the soil pH value and salt content of the comparative example treatment group also decreased to a certain extent, the effect was not as significant as that of the example, and the crop growth was also poor. The soil conditions of the blank control group were hardly improved, and the crop growth was severely inhibited, which was manifested as a lower emergence rate, yield and higher disease rate.

[0077] The present invention uses the soil salinity-alkali modifier prepared in Example 1 for Figure 1 The heavy saline-alkali land shown in the figure was used for soil improvement. The amount of 70.0 kg / mu was applied once every 6 months. After continuous application for 2 years, the Figure 2 The restored landform is shown.

[0078] In summary, the test results of this test example fully prove that the soil salinity-alkali conditioner provided by Examples 1 to 3 has a significant effect in improving the soil conditions of severe saline-alkali land, promoting crop growth and increasing yield through a specific structure, and has broad application prospects.

[0079] As described above, the basic principle, main features and advantages of the present invention are well described. The above embodiments and descriptions are only descriptions of the preferred implementation modes of the present invention, and the present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, various changes and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the protection scope determined by the present invention.

Claims

1. A soil salinity modifier, characterized in that: The soil salinity-alkali improver is composed of an outer shell slow-release layer, a middle conditioning layer and an inner functional layer; The internal functional layer is a saline-alkali land improving bacterial agent, biochar and a granulation binder; The middle conditioning layer is composed of a conditioning agent, a first sustained-release agent and a first solvent; The shell sustained-release layer is composed of humic acid, furfural residue, calcium ion compound, a second sustained-release agent and a second solvent; The calcium ion compound is at least one of phosphogypsum, desulfurized gypsum, calcium chloride and calcium sulfate; The conditioning agent is at least one of coumarin, resveratrol and catechins.

2. The soil salinity modifier according to claim 1, characterized in that The biochar is fruit shell biochar or straw biochar.

3. The soil salinity modifier according to claim 1, characterized in that In terms of mass percentage, the composition of the granulation adhesive is 0.1-5% of a thickener, 0.01-10% of a tackifier, 1-5% of a stabilizer, and the balance is water.

4. The soil salinity modifier according to claim 3, characterized in that The stabilizer is selected from at least one of carboxymethyl cellulose, water-soluble biopolysaccharide, sodium alginate and sodium polyacrylate; The thickener is selected from at least one of gelatin, xanthan gum, sodium alginate and agar; The tackifier is selected from at least one of polyvinyl alcohol, polyethylene glycol and polyacrylamide.

5. The soil salinity modifier according to claim 1, characterized in that: The first sustained-release agent or the second sustained-release agent is independently selected from at least one of gelatin, xanthan gum, sodium alginate, and agar; The first solvent and the second solvent are water.

6. A method for preparing the soil salinity-alkali conditioner according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: after uniformly mixing the saline-alkali land improving bacterial agent and the biochar, the mixture is mixed with the granulation binder for granulation to obtain an inner core as the inner functional layer; Step 2: mixing and stirring the conditioning agent, the first sustained-release agent and the first solvent to prepare a first suspension; Step 3: mixing the inner core and the first suspension, granulating and drying to obtain a semi-finished product; Step 4: mixing and stirring humic acid, furfural residue, the calcium ion compound, the second sustained-release agent and the second solvent to obtain a second suspension; Step 5: Mix the semi-finished product and the second suspension, granulate and then dry to obtain the soil salinity-alkali conditioner.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the saline-alkali land improving bacterial agent to the biochar is 30-50:10-15; In terms of mass percentage, the granulation binder is 1 to 3% of the sum of the mass of the saline-alkali land improving bacterial agent and the biochar; The mass ratio of the conditioning agent, the first sustained-release agent and the first solvent is 30-50:1-5:100; The mass ratio of the humic acid, the furfural residue, the calcium ion compound, the second sustained-release agent and the second solvent is 10-15:10-15:20-30:1-5:

100.

8. The preparation method according to claim 6, characterized in that: The particle size of the inner core is 4 to 6 mm, the particle size of the semi-finished product is 1 to 2 mm larger than that of the inner core, and the particle size of the soil salinity-alkali improver is 2 to 4 mm larger than that of the semi-finished product.

9. Use of the soil salt-alkali improver according to any one of claims 1 to 5, or the soil salt-alkali improver prepared by the preparation method according to any one of claims 6 to 8 in improving saline-alkali soil.

10. The use according to claim 9, characterized in that: Used for at least one of increasing crop yield, reducing hydrogen peroxide content in crops, reducing superoxide anion levels in crops, reducing pH of saline-alkali soil, and reducing salt content of saline-alkali soil.

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