Soil conditioner for improving saline-alkali soil and application of soil conditioner in aspect of increasing corn planting yield in saline-alkali soil

Abstract

The invention belongs to the technical field of saline-alkali soil improvement, and particularly relates to a soil conditioner for improving saline-alkali soil and application of the soil conditioner in the aspect of improving the corn planting yield in the saline-alkali soil. The soil conditioner for improving the saline-alkali soil is prepared from the raw materials including the jerusalem artichoke extract, the apocynum venetum extract, the humic acid, the charcoal, the kieselguhr and the complex microbial inoculant, and after the soil conditioner is used for improving the saline-alkali soil, the physical and chemical properties of soil can be remarkably improved, and the corn yield (dry weight) can be remarkably increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of saline-alkali soil improvement, and more specifically relates to a soil conditioner for improving saline-alkali soil and its application in increasing the yield of maize planted in saline-alkali soil. Background Art

[0002] Saline-alkali soil, as one of the major challenges faced by global agriculture, is characterized by high concentrations of Na + , Cl - and other ions in the soil, which lead to an alkaline pH value, causing problems such as soil compaction, poor permeability, and low organic matter content, severely inhibiting crop root development and nutrient absorption. Especially in maize planting areas, salinization greatly limits the yield and quality of maize, posing a major threat to agricultural production. Traditional improvement measures such as freshwater leaching and gypsum application can alleviate saline-alkali problems to a certain extent, but they generally suffer from high costs, short-lived effects, and the risk of secondary pollution.

[0003] Currently, most of the existing soil conditioners on the market rely on single-functional materials (such as humic acid or biochar). Although these materials can play a certain role in improving soil structure, there are still many deficiencies. Firstly, these conditioners usually can only adjust the soil pH value or adsorb salts, lacking the comprehensive ability to promote plant stress resistance; secondly, due to the dependence of some products on expensive synthetic materials (such as polyacrylamide), the production cost remains high; in addition, the improvement effect often disappears rapidly with irrigation or rainfall, showing poor persistence; more importantly, chemical modifiers may have a negative impact on the soil microbial community, thus disrupting the ecological balance.

[0004] Therefore, developing a new type of soil conditioner that is efficient, economical, and environmentally friendly is of great significance for solving the problem of low yield in maize planting in saline-alkali soil. Summary of the Invention

[0005] The purpose of the present invention is to provide a soil conditioner for improving saline-alkali soil and its application in increasing the yield of maize planted in saline-alkali soil to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention: Provide a soil conditioner for improving saline-alkali soil, and by mass, the raw materials include:

[0008] 0.5 - 1 part of Jerusalem artichoke extract, 0.3 - 0.6 part of Apocynum venetum extract, 15 - 20 parts of humic acid, 20 - 30 parts of biochar, 30 - 40 parts of diatomite, and 1 - 2 parts of compound bacterial agent.

[0009] Furthermore, the inulin content in the Jerusalem artichoke extract is ≥ 30%.

[0010] Furthermore, the total flavonoid content in the Apocynum venetum extract is ≥ 15%.

[0011] Furthermore, the biochar is corn straw biochar with a specific surface area of ≥ 300 m 2 / g.

[0012] Furthermore, the degree of humification of the humic acid is ≥ 60%.

[0013] Furthermore, the SiO2 content in the diatomite is ≥ 80%.

[0014] Furthermore, the compound microbial agent is obtained by solid-state fermentation using Bacillus subtilis and Paenibacillus mucilaginosus as compound bacteria and bentonite and wheat bran as carriers. Among them, the bacterial content of Bacillus subtilis and Paenibacillus mucilaginosus is not less than 10 8 cfu / g, and the bacterial content of the compound microbial agent is not less than 10 8 cfu / g.

[0015] Optionally, the mass ratio of Bacillus subtilis to Paenibacillus mucilaginosus is 1:1.

[0016] Optionally, the mass ratio of bentonite to wheat bran is 3:1.

[0017] Optionally, the mass ratio of the compound bacteria to the carrier is 1:20.

[0018] The second technical solution of the present invention: provides a preparation method of the above soil conditioner for improving saline-alkali soil, and the steps include:

[0019] Mix the biochar, diatomite and humic acid evenly to obtain a porous composite carrier;

[0020] Add the Jerusalem artichoke extract and the Apocynum venetum extract into water and disperse them ultrasonically to obtain a mixed solution;

[0021] Load the mixed solution onto the porous composite carrier by spray loading, stir evenly, add the compound microbial agent, and mix evenly to obtain the soil conditioner for improving saline-alkali soil.

[0022] Furthermore, the mass ratio of the sum of the Jerusalem artichoke extract and the Apocynum venetum extract to the mass of water is 1:5.

[0023] Furthermore, the parameters of the ultrasonic dispersion are: 40 kHz, 10 min.

[0024] The present invention first constructs a biochar-diatomite-humic acid porous framework, then loads plant extracts to avoid the active ingredients being blocked by pores, and finally adds a composite bacterial agent to ensure the survival rate of the bacterial species in the composite bacterial agent, minimizing the impact of the preparation steps on the bacterial species.

[0025] The third technical solution of the present invention: Provide an application of the above-mentioned soil conditioner for improving saline-alkali land in increasing the yield of corn planted in saline-alkali land.

[0026] The present invention discloses the following technical effects:

[0027] In the components of the soil conditioner for improving saline-alkali land of the present invention, Jerusalem artichoke inulin serves as a microbial carbon source to promote the proliferation of the composite bacterial agent and accelerate the adsorption of salt ions (Na + ); Apocynum venetum flavonoids inhibit the absorption of Cl by corn roots - , and at the same time activate the antioxidant enzyme system; diatomite and biochar form a porous complex to extend the salt adsorption period.

[0028] The soil conditioner composition for improving saline-alkali land provided by the present invention can significantly increase the soil desalination rate, keep the soil pH stable, enhance the root activity of corn, increase the lignin content of straw (anti-lodging), and significantly increase the yield of corn (dry weight) after application. Specific Embodiments

[0029] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0030] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0032] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0033] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0034] It should be noted that the aspects not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0035] Unless otherwise specified, "normal temperature" and "room temperature" involved in the specific embodiments of the present invention both refer to 20 - 30 °C; the "parts" involved are all "parts by mass".

[0036] The extraction method of the Jerusalem artichoke extract used in the specific embodiments of the present invention is as follows:

[0037] S1. After cleaning the Jerusalem artichoke tubers (Qingyu No. 2), cut them into thin slices with a thickness between 3 - 5 mm, dry them at 60 °C with hot air until the moisture content ≤ 8%, and then crush and pass through a 60 - mesh sieve to obtain Jerusalem artichoke powder;

[0038] S2. Set the water - material ratio to 15:1 (mass ratio, water:Jerusalem artichoke powder), then adjust the pH to between 5.0 - 5.5 with citric acid (to promote the dissolution of inulin), carry out stirring extraction in a constant - temperature water bath at 85 °C for 2 h, then immediately raise the temperature to 95 °C and maintain for 10 min (to inhibit enzyme activity), finally centrifuge at 4000 rpm for 15 min, take the supernatant, add activated carbon accounting for 1% of the supernatant mass, stir and decolorize at 70 °C for 30 min, filter, and vacuum - concentrate (at 60 °C, - 0.08 MPa) until the solid content ≥ 30%, and spray - dry (inlet air temperature 180 °C, outlet air temperature 80 °C) to obtain a light - yellow powder, which is the Jerusalem artichoke extract. Measured by the phenol - sulfuric acid method, the inulin content ≥ 30%. GB5009.3 - 2016, the moisture content ≤ 5%.

[0039] The extraction method of the Apocynum venetum extract used in the specific embodiments of the present invention is as follows:

[0040] S1. Dry the Apocynum venetum leaves (leaves before flowering) at 40 °C until the moisture content ≤ 10%, crush, and pass through a 40 - mesh sieve to obtain Apocynum venetum powder;

[0041] S2. Use ethanol with a volume fraction of 65% as the extraction solvent, and obtain the extract by ethanol reflux extraction. The material - liquid ratio is 1:20 (mass ratio, Apocynum venetum powder:ethanol), reflux extract at 75 °C for 2 times, 1.5 h each time, and use ultrasonic assistance (300 W, 40 kHz) during the extraction process;

[0042] S3. Combine the extractives obtained twice, filter with a 400-mesh filter cloth, and perform rotary evaporation (50 °C, -0.06 MPa) until there is no alcohol smell. Subsequently, conduct macroporous resin purification (resin model: AB-8 macroporous resin; sample loading flow rate: 2 BV / h (column volume); eluent: 70% ethanol, elution volume 3 BV), and freeze-dry (-50 °C, 24 h) to obtain a brownish powder, which is the Apocynum venetum extract. The total flavonoids are determined by the aluminum nitrate-sodium nitrite colorimetric method (calculated as rutin) to be ≥15%; the lead (Pb) is determined according to GB 5009.12-2017 to be ≤5 mg / kg.

[0043] The extraction method of the seabuckthorn extract used in the specific implementation plan of the present invention is as follows:

[0044] S1. After cleaning the mature seabuckthorn fruits to remove impurities, soak them in 0.5% NaCl solution for 10 minutes, rinse with clear water 3 times, dry at 50 °C hot air until the moisture content ≤10%, pulverize, and pass through a 40-mesh sieve to obtain seabuckthorn powder;

[0045] S2. Hot water extraction:

[0046] Ratio of water to material: 1:20 (mass ratio, seabuckthorn powder: water);

[0047] Temperature and time: Constant temperature extraction at 90 °C for 3 times, 1 hour each time;

[0048] pH adjustment: Adjust the pH to 7.0 - 7.5 with NaHCO3;

[0049] Enzyme inactivation: Inactivate in a boiling water bath for 5 minutes;

[0050] S3. Separation and purification:

[0051] Centrifugation: Centrifuge at 5000 rpm for 20 minutes and combine the supernatant;

[0052] Protein removal: Repeatedly remove protein by the Sevage method (chloroform: n-butanol = 4:1) until there is no precipitate;

[0053] Alcohol precipitation: Add 3 volumes of 95% ethanol, let stand at 4 °C for 12 hours, and centrifuge to collect the precipitate;

[0054] Drying: Vacuum freeze-dry (-45 °C, 24 h) to obtain a light yellow powder, which is the seabuckthorn extract.

[0055] Determined by the phenol-sulfuric acid method, the polysaccharide content is ≥25%; ash content: ≤5% (GB 5009.4-2016).

[0056] The extraction method of the Suaeda salsa extract used in the specific implementation plan of the present invention is as follows:

[0057] S1. Take the whole plant of Suaeda salsa (harvested at the full flowering stage and dried to a moisture content of ≤12%), crush it and pass through a 30-mesh sieve to obtain Suaeda salsa powder;

[0058] S2. Water extraction and alcohol precipitation method:

[0059] Solvent: Deionized water;

[0060] Ratio of material to liquid: 1:15 (mass ratio, Suaeda salsa powder: water);

[0061] Temperature and time: Ultrasonic-assisted extraction at 80°C (power 250 W, frequency 40 kHz) for 2 hours;

[0062] Filtration: Filter by double-layer filter paper under suction and collect the filtrate;

[0063] S3. Betaine enrichment:

[0064] Purification by ion exchange resin:

[0065] Resin model: 001×7 strong acidic cation resin;

[0066] Sample loading flow rate: 1.5 BV / h;

[0067] Eluent: 5% ammonia water solution, elution volume 4 BV;

[0068] Concentration and crystallization:

[0069] Concentrate the eluate under reduced pressure to 1 / 5 of the original volume and let it stand for crystallization at 4°C for 24 hours;

[0070] Filter the crystals and dry them at 60°C to obtain a white crystalline powder, which is the Suaeda salsa extract.

[0071] Riecke's salt precipitation method (verified by HPLC), betaine ≥10%; chloride ion residue: ≤0.5% (GB 5009.44-2016).

[0072] The biochar used in the specific implementation of the present invention is corn straw biochar (reuse of agricultural products), with a specific surface area of ≥300 m 2 / g, and the specific preparation steps are as follows:

[0073] Pyrolyze corn straw (carbon content ≥35%) under oxygen-limited conditions at 600°C for 2 h, cool and crush it to 80 mesh, soak it in 1 mol / L hydrochloric acid for 24 hours (to remove ash), wash it with clear water until neutral, and dry it at 105°C to obtain the corn straw biochar.

[0074] The SiO2 content of the diatomite used in the specific implementation of the present invention is ≥80%, and the preparation steps are as follows:

[0075] Calcine natural diatomite (SiO2 ≥80%) at 500°C for 3 hours and pass it through a 100-mesh sieve to obtain diatomite.

[0076] In the specific implementation of the present invention, the total bacterial content of the compound bacterial agent used is not less than 10 8 cfu / g, and the specific preparation steps include:

[0077] Mix Bacillus subtilis and Paenibacillus mucilaginosus in a mass ratio of 1:1 to obtain a mixed bacterium;

[0078] Mix bentonite (specific surface area > 250m 2 / g) and bran in a mass ratio of 3:1, and sterilize (121°C, 20 min) to use as a carrier;

[0079] Mix the mixed bacterium and the carrier in a mass ratio of 1:20, and perform solid-state fermentation at 30°C for 48 h to obtain the compound bacterial agent.

[0080] Unless otherwise specified, the raw materials used in the specific implementation of the present invention are all commercially available products, and the purchase channels do not affect the realization of the technical effects.

[0081] The degree of humification of the humic acid used in the present invention is ≥60%; the Bacillus subtilis and Paenibacillus mucilaginosus in the compound bacterial agent used are provided by Shandong Xinxiong Biotechnology Co., Ltd., and the bacterial content is not less than 10 9 cfu / g.

[0082] Example 1

[0083] The preparation steps of the soil conditioner for improving saline-alkali land include:

[0084] S1. Raw material preparation: 0.8 parts of Jerusalem artichoke extract, 0.5 parts of Apocynum venetum extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite, and 1.5 parts of compound bacterial agent;

[0085] S2. Mix biochar, diatomite, and humic acid evenly using a double-helix conical mixer (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40°C) to obtain a porous composite carrier;

[0086] S3. Add Jerusalem artichoke extract and Apocynum venetum extract to deionized water (solid-liquid ratio 1:5), and perform ultrasonic dispersion (40 kHz, 10 min) to obtain a mixed solution;

[0087] S4. Load the mixed solution onto the porous composite carrier by spray loading, stir evenly, add the compound bacterial agent, and mix evenly to obtain the soil conditioner for improving saline-alkali land.

[0088] Example 2

[0089] The preparation steps of the soil conditioner for improving saline-alkali land include:

[0090] S1. Raw material preparation: 1 part of Jerusalem artichoke extract, 0.3 part of Apocynum venetum extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite, and 1.5 parts of compound microbial agent;

[0091] S2. Mix the biochar, diatomite, and humic acid evenly using a double - helix conical mixer (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a porous composite carrier;

[0092] S3. Add the Jerusalem artichoke extract and Apocynum venetum extract to deionized water (solid - liquid ratio 1:5), and perform ultrasonic dispersion (40 kHz, 10 min) to obtain a mixed solution;

[0093] S4. Load the mixed solution onto the porous composite carrier by spray loading. After stirring evenly, add the compound microbial agent and mix evenly to obtain a soil conditioner for improving saline - alkali soil.

[0094] Example 3

[0095] The preparation steps of the soil conditioner for improving saline - alkali soil include:

[0096] S1. Raw material preparation: 0.5 part of Jerusalem artichoke extract, 0.6 part of Apocynum venetum extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite, and 1.5 parts of compound microbial agent;

[0097] S2. Mix the biochar, diatomite, and humic acid evenly using a double - helix conical mixer (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a porous composite carrier;

[0098] S3. Add the Jerusalem artichoke extract and Apocynum venetum extract to deionized water (solid - liquid ratio 1:5), and perform ultrasonic dispersion (40 kHz, 10 min) to obtain a mixed solution;

[0099] S4. Load the mixed solution onto the porous composite carrier by spray loading. After stirring evenly, add the compound microbial agent and mix evenly to obtain a soil conditioner for improving saline - alkali soil.

[0100] Comparative Example 1

[0101] Compared with Example 1, the difference is that the Jerusalem artichoke extract is replaced with an equal amount of Apocynum venetum extract. The specific steps are as follows:

[0102] S1. Raw material preparation: 1.3 parts of Apocynum venetum extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite, and 1.5 parts of compound microbial agent;

[0103] S2. Mix the biochar, diatomite, and humic acid evenly using a double - helix conical mixer (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a porous composite carrier;

[0104] S3. Add the Apocynum venetum extract into deionized water (solid-liquid ratio 1:5), and perform ultrasonic dispersion (40 kHz, 10 min) to obtain an Apocynum venetum extract solution;

[0105] S4. Load the Apocynum venetum extract solution onto the porous composite carrier by spray loading. After stirring evenly, add the composite bacterial agent and mix evenly to obtain a soil conditioner for improving saline-alkali soil.

[0106] Comparative Example 2

[0107] Compared with Example 1, the difference is that the Apocynum venetum extract is replaced with an equal amount of Jerusalem artichoke extract. The specific steps are as follows:

[0108] S1. Raw material preparation: 1.3 parts of Jerusalem artichoke extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite, and 1.5 parts of composite bacterial agent;

[0109] S2. Use a double-screw conical mixer to mix the biochar, diatomite, and humic acid evenly (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a porous composite carrier;

[0110] S3. Add the Jerusalem artichoke extract into deionized water (solid-liquid ratio 1:5), and perform ultrasonic dispersion (40 kHz, 10 min) to obtain a Jerusalem artichoke extract solution;

[0111] S4. Load the Jerusalem artichoke extract solution onto the porous composite carrier by spray loading. After stirring evenly, add the composite bacterial agent and mix evenly to obtain a soil conditioner for improving saline-alkali soil.

[0112] Comparative Example 3

[0113] The preparation steps of the conventional soil conditioner include:

[0114] S1. Raw material preparation: 18 parts of humic acid, 25 parts of biochar, and 35 parts of gypsum;

[0115] S2. Use a double-screw conical mixer to mix the biochar, gypsum, and humic acid evenly (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a conventional soil conditioner.

[0116] Comparative Example 4

[0117] Compared with Example 1, the difference is that the Jerusalem artichoke extract is replaced with an equal amount of sea buckthorn extract. The specific steps are as follows:

[0118] S1. Raw material preparation: 0.8 part of sea buckthorn extract, 0.5 part of Apocynum venetum extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite, and 1.5 parts of composite bacterial agent;

[0119] S2. Mix biochar, diatomite and humic acid evenly using a double - helix conical mixer (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a porous composite carrier;

[0120] S3. Add seabuckthorn extract and apocynum venetum extract to deionized water (solid - liquid ratio 1:5), and disperse ultrasonically (40 kHz, 10 min) to obtain a mixed solution;

[0121] S4. Load the mixed solution onto the porous composite carrier by spray loading. After stirring evenly, add a composite microbial agent and mix evenly to obtain a soil conditioner for improving saline - alkali soil.

[0122] Comparative Example 5

[0123] Compared with Example 1, the difference is that the apocynum venetum extract is replaced with an equal amount of suaeda salsa extract. The specific steps are as follows:

[0124] S1. Raw material preparation: 0.8 parts of jerusalem artichoke extract, 0.5 parts of suaeda salsa extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite and 1.5 parts of composite microbial agent;

[0125] S2. Mix biochar, diatomite and humic acid evenly using a double - helix conical mixer (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a porous composite carrier;

[0126] S3. Add jerusalem artichoke extract and suaeda salsa extract to deionized water (solid - liquid ratio 1:5), and disperse ultrasonically (40 kHz, 10 min) to obtain a mixed solution;

[0127] S4. Load the mixed solution onto the porous composite carrier by spray loading. After stirring evenly, add a composite microbial agent and mix evenly to obtain a soil conditioner for improving saline - alkali soil.

[0128] Comparative Example 6

[0129] Compared with Example 1, the difference is that the jerusalem artichoke extract is replaced with an equal amount of seabuckthorn extract, and the apocynum venetum extract is replaced with an equal amount of suaeda salsa extract. The specific steps are as follows:

[0130] S1. Raw material preparation: 0.8 parts of seabuckthorn extract, 0.5 parts of suaeda salsa extract, 18 parts of humic acid, 25 parts of biochar, 35 parts of diatomite and 1.5 parts of composite microbial agent;

[0131] S2. Mix biochar, diatomite and humic acid evenly using a double - helix conical mixer (rotation speed 25 rpm, mixing time 30 minutes, temperature ≤ 40 °C) to obtain a porous composite carrier;

[0132] S3. Add seabuckthorn extract and Suaeda salsa extract into deionized water (solid-liquid ratio 1:5), and perform ultrasonic dispersion (40 kHz, 10 min) to obtain a mixed solution;

[0133] S4. Load the mixed solution onto a porous composite carrier by spray loading. After stirring evenly, add a composite microbial agent, and mix evenly to obtain a soil conditioner for improving saline-alkali land.

[0134] Test Example

[0135] Apply the modifiers prepared in Examples 1-3 and Comparative Examples 1-6 to saline-alkali land (initial pH 8.6, conductivity 4.2 mS / cm, Na + content 1.2%). The application rate is 100 kg / mu. After application, rotary tillage is carried out to a depth of 20-25 cm, and flood irrigation is carried out. Subsequently, corn (Jingke 968) is planted, and the same field management measures are adopted after planting.

[0136] Among them, Examples 1-3, Comparative Examples 1-6, and no application of any modifier (blank control group) total 10 groups, with 3 replicates in each group and 100 m for each replicate 2 . During the planting period, plant height, stem diameter, and chlorophyll SPAD value are detected, and the physical and chemical properties of the soil before applying the modifier, as well as the physical and chemical properties of the soil after harvesting corn, are compared. The corn yield (grain dry weight) and straw yield are statistically analyzed. The specific results are shown in Table 1.

[0137] The plant height is measured at the tasseling stage, which is the vertical distance from the ground base (junction of root and stem) to the top of the male spike of the plant. Randomly select 10 plants in each replicate and take the average value.

[0138] The stem diameter is measured at the early filling stage (vernier caliper). At the middle of the third internode at the base of the stem, the stem diameter is measured horizontally, avoiding the swollen area of the node. Measure 3 times in different directions for each plant. Randomly select 10 plants in each replicate and take the average value.

[0139] The chlorophyll SPAD value is detected at the filling stage, at the middle of the ear leaf (avoiding the main vein). Randomly select 10 plants in each replicate, and select 3 points on the same leaf for measurement and take the average value.

[0140] Table 1

[0141]

[0142]

[0143] It can be found from the data in Table 1 that after harvesting corn in Example 1, the pH decreased from 8.6 to 7.6, and the conductivity decreased by 38.9% (only 25.3% in Comparative Example 3), indicating that the Jerusalem artichoke-Apocynum venetum combination significantly improved the desalination efficiency. Na +Content reduction: In Example 1, it reached 41.5% (only 15.6% in Comparative Example 1), verifying the adsorption effect of inulin-promoting bacteria on Na + .

[0144] In plant height, Example 1 (195 cm) was 34.5% higher than the blank group (145 cm), and Comparative Example 6 (158 cm) had the worst effect due to the lack of synergistic effect. In stem diameter, Example 1 (22.5 mm) was 12% higher than Comparative Example 2 (20.1 mm), proving that flavonoids enhance stem lignification. In SPAD value, Example 1 (48.6) was significantly higher than Comparative Example 5 (39.1), reflecting the antioxidant protection effect of Apocynum venetum flavonoids.

[0145] In grain dry weight, Example 1 (485 kg / mu) was 18.3% higher than Comparative Example 3 (410 kg / mu), indicating the positive regulation of the plant extract combination on the filling stage.

[0146] In root activity, Example 1 (28.4 μg / g·h) far exceeded Comparative Example 4 (17.2 μg / g·h), indicating that inulin-flavonoid synergistically activates root metabolism.

[0147] The improvement effects of Comparative Examples 4-6 (substituted by sea buckthorn and Suaeda glauca) were significantly lower than those of Examples 1-3, indicating that the use of Jerusalem artichoke and Apocynum venetum extracts in this application has a synergistic effect. When other extracts are used for substitution, the realization of technical effects will be significantly affected.

[0148] In this specification, each example is described in a progressive manner. The key point of each example is to illustrate the differences from other examples. The same or similar parts among the examples can be referred to each other.

[0149] The above description of the disclosed examples enables those skilled in the art to implement or use the present invention. Various modifications to these examples will be obvious to those skilled in the art. The general principles defined herein can be implemented in other examples without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these examples shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A soil conditioner for improving saline-alkali soil, characterized in that, By mass fraction, the raw materials include: 0.5 - 1 part of Jerusalem artichoke extract, 0.3 - 0.66 part of Apocynum venetum extract, 15 - 20 parts of humic acid, 20 - 30 parts of biochar, 30 - 40 parts of diatomite, and 1 - 2 parts of compound microbial agent.

2. The soil conditioner for improving saline-alkali soil according to claim 1, characterized in that, The inulin content in the Jerusalem artichoke extract is ≥ 30%; and / or, the total flavonoid content in the Apocynum venetum extract is ≥ 15%.

3. The soil conditioner for improving saline-alkali soil according to claim 1, characterized in that, The biochar is corn straw biochar, with a specific surface area ≥ 300 m 2 / g.

4. The soil conditioner for improving saline-alkali soil according to claim 1, characterized in that, The humification degree of the humic acid is ≥ 60%.

5. The soil conditioner for improving saline-alkali soil according to claim 1, characterized in that, The SiO2 content of the diatomite is ≥ 80%.

6. The soil conditioner for improving saline-alkali soil according to claim 1, characterized in that, The compound microbial agent is obtained by solid-state fermentation with Bacillus subtilis and Paenibacillus mucilaginosus as the compound bacteria and bentonite and bran as the carriers.

7. The soil conditioner for improving saline-alkali land according to claim 6, wherein The mass ratio of Bacillus subtilis to Paenibacillus mucilaginosus is 1:1; and / or, the mass ratio of bentonite to bran is 3:1; and / or, the mass ratio of the compound bacteria to the carrier is 1:

20.

8. A method for preparing a soil conditioner for improving saline-alkali soil according to any one of claims 1-7, characterized in that the steps It includes: Mix biochar, diatomite and humic acid evenly to obtain a porous composite carrier; Add the Jerusalem artichoke extract and the Apocynum venetum extract into water and disperse them ultrasonically to obtain a mixed solution; Load the mixed solution onto the porous composite carrier by spray loading, stir evenly, then add the compound microbial agent, and mix evenly to obtain the soil conditioner for improving saline-alkali land.

9. The preparation method according to claim 8, characterized in that, The mass ratio of the sum of the masses of the Jerusalem artichoke extract and the Apocynum venetum extract to the mass of water is 1:5; and / or, the parameters of the ultrasonic dispersion are: 40 kHz, 10 min.

10. Use of a soil conditioner for improving saline-alkali land according to any one of claims 1 - 7 in increasing the yield of corn planted in saline-alkali land.

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