Soil conditioner for improving saline-alkali soil in Xinjiang region

Abstract

The invention discloses a soil conditioner for improving saline-alkali soil in the Xinjiang region, and belongs to the technical field of soil conditioners, and the soil conditioner is spherical and comprises a water retention layer, a compound fertilizer layer, a compound bacteria nutrient layer and a microorganism compound layer from outside to inside in sequence. The soil conditioner for improving the saline-alkali soil in the Xinjiang region, provided by the invention, not only can effectively prevent a soil hardening phenomenon, but also can remarkably improve the water and fertilizer retention capability of soil, enhance the stress resistance of crops and improve the yield of the crops.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil conditioners, and particularly relates to a soil conditioner for improving saline-alkali land in Xinjiang region. Background Art

[0002] Regarding the problem of improving saline-alkali land in Xinjiang region, the traditional improvement methods are as follows: Physical improvement: such as deep plowing and covering to suppress salt or achieving the purpose of washing salt by irrigating fresh water. However, the Xinjiang region is generally arid and lacks fresh water resources; Chemical improvement: such as applying acid-base regulating substances or supplementing humic acid substances to supplement organic matter. However, gypsum is likely to cause excessive calcium ions and may trigger new salt accumulation. Humic acid has a slow effect, and due to the insufficient microbial activity in the low-temperature environment in Xinjiang, it is difficult to play a role; Biological improvement: introducing salt-tolerant microbial agents. However, in the saline-alkali soil in Xinjiang, the stability of the bacterial strains is generally poor, and the improvement effect is not good.

[0003] Therefore, there is an urgent need to develop a soil conditioner for improving saline-alkali land in Xinjiang region, which can synchronously solve the problems of saline-alkali stress, lack of organic matter, and nutrient imbalance through the synergistic effect of organic-inorganic-microorganisms. Summary of the Invention

[0004] The purpose of the present invention is to provide a soil conditioner for improving saline-alkali land in Xinjiang region to solve the problems existing in the above-mentioned prior art.

[0005] One of the technical solutions provided by the present invention:

[0006] A soil conditioner for improving saline-alkali land in Xinjiang region, the soil conditioner is spherical, and from the outside to the inside, it is successively a water retention layer, a compound fertilizer layer, a compound bacterial nutrient layer, and a microbial composite layer.

[0007] Preferably, the mass ratio of the water retention layer, the compound fertilizer layer, the compound bacterial nutrient layer, and the microbial composite layer is (1 - 2)∶(2 - 4)∶1∶(2 - 3).

[0008] Another technical solution provided by the present invention:

[0009] A preparation method of the above-mentioned soil conditioner for improving saline-alkali land in Xinjiang region, including the following steps: Weigh the precursors of the water retention layer, the compound fertilizer layer, the compound bacterial nutrient layer, and the microbial composite layer according to the mass ratio; Prepare the precursor of the microbial composite layer into particles as the inner core; Wrap the precursor of the compound bacterial nutrient layer on the surface of the inner core to obtain a secondary inner core; Wrap the precursor of the compound fertilizer layer on the surface of the secondary inner core to obtain a tertiary inner core; Wrap the precursor of the water retention layer on the surface of the tertiary inner core to obtain the soil conditioner for improving saline-alkali land in Xinjiang region.

[0010] Preferably, the method for preparing the microbial composite layer precursor comprises the following steps: mixing the composite bacterial powder and the binder solution to obtain the microbial composite layer precursor.

[0011] More preferably, the composite bacterial powder comprises bacillus subtilis powder and bacillus megaterium powder, and the mass ratio of the bacillus subtilis powder to the bacillus megaterium powder is 3:1.

[0012] Preferably, the method for preparing the composite bacterial nutrient layer precursor comprises the following steps: mixing the composite bacterial nutrient and the binder solution to prepare the composite bacterial nutrient layer precursor.

[0013] Preferably, the method for preparing the composite fertilizer layer precursor comprises the following steps: mixing urea, potassium sulfate, diammonium phosphate, humic acid and gypsum, adding the binder solution, and dropping phosphoric acid to adjust the pH value to obtain the composite fertilizer layer precursor.

[0014] More preferably, the mass ratio of urea, potassium sulfate, diammonium phosphate, humic acid and gypsum is 4:3:2:5:4.

[0015] More preferably, the pH value is 7-8.

[0016] Preferably, the method for preparing the water retention layer precursor comprises the following steps: adding kaolin to the sodium polyglutamate aqueous solution, adjusting the pH to 4-5, adding a crosslinking agent, and carrying out a crosslinking reaction to obtain a polyglutamate-kaolin gel. After drying and pulverizing the polyglutamate-kaolin gel, adding the binder solution to prepare the water retention layer precursor.

[0017] More preferably, the mass ratio of sodium polyglutamate, kaolin and the crosslinking agent is 1:(0.3-0.5):(0.3-0.8).

[0018] More preferably, the crosslinking agent is selected from ethylene glycol diglycidyl ether or polyethylene glycol diglycidyl ether.

[0019] More preferably, the temperature of the crosslinking reaction is 40-60°C and the time is 6-10h.

[0020] Sodium polyglutamate has good water solubility, biodegradability, and moisture retention performance. In the present invention, it serves as the main gelling substance and forms a gel network structure under the action of a crosslinking agent. Kaolin, as a filler, can enhance the mechanical strength and stability of the gel. Under the condition of pH = 4 - 5 (lower than the isoelectric point of sodium polyglutamate, which is 3.22), the carboxyl groups on the molecular chain of sodium polyglutamate are partially protonated, making it carry a positive charge or reducing its charge, enhancing its hydrophilicity, and contributing to the dispersion and stretching of the molecular chain in water. The surface of kaolin is negatively charged and adsorbs and wraps around the positively charged molecular chain of sodium polyglutamate through charge attraction, forming a uniform mixture, preventing particle aggregation and sedimentation, and promoting the uniform progress of subsequent crosslinking reactions. After adding the crosslinking agent, the crosslinking agent bridges the functional groups of the sodium polyglutamate molecular chain to form chemical bond connections. Since the sodium polyglutamate molecular chain has been uniformly adsorbed on the surface of kaolin particles, the crosslinking reaction forms a network structure between the kaolin particles, firmly binding the particles, and finally forming the polyglutamic acid-kaolin gel.

[0021] The core microbial layer of the present invention decomposes some of the salts in the soil through metabolic activities; the composite bacterial nutrient layer provides a continuous carbon source (such as starch, cellulose) and trace elements for the microorganisms, maintains their activity, and accelerates the salt conversion process; the water retention layer increases the soil field water holding capacity and promotes the discharge of salts with deep seepage; the layered structure of the soil conditioner provided by the present invention has a certain controlled release and long-term effect, and the wrapping structure from the inside out realizes the slow release of nutrients and microorganisms, avoiding short-term concentration fluctuations of salts caused by rapid leaching.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] The present invention uses a layer-by-layer granulation technology to prepare the soil conditioner, and its core lies in constructing a multi-functional layered structure. The inner core layer, that is, the microbial composite layer, can improve the soil microbial community structure. Adjacent to the inner core is the composite bacterial nutrient layer, which can provide essential nutrients for the microorganisms in actual application, stimulate their reproductive vitality and metabolic functions, and further promote the balance and development of the soil ecosystem. The compound fertilizer layer, as a key part of nutrient supply, scientifically formulates various nutrient elements required for plant growth and development, effectively promotes crop growth, and improves soil fertility. The water retention layer specifically solves the problem of rapid water loss in the soil of arid regions, significantly enhances the water retention capacity of the soil, and provides a stable water environment for crop growth. For the unique saline-alkali soil in Xinjiang region (high salinity, extreme drought, and soil infertility), the present invention ensures that no adverse chemical reactions or mutual interferences occur between the functional layers during the pressing process.

[0024] The soil conditioner provided by the present invention for improving saline-alkali soil in Xinjiang region can not only effectively prevent soil compaction, but also significantly improve the water and fertilizer retention capacity of the soil, enhance the stress resistance of crops, and increase crop yields. Detailed Embodiments

[0025] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be construed as a limitation on the present invention, but rather as a more detailed description of certain aspects, features, and implementation manners of the present invention.

[0026] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended 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. Each 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.

[0027] 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 may 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.

[0028] 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.

[0029] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0030] The room temperature in the present invention refers to 25 ± 2°C.

[0031] In the embodiments of the present invention, "parts" are "parts by mass" unless otherwise specified.

[0032] In the embodiments of the present invention, the Bacillus subtilis powder was purchased from Jinan Hore Biotechnology Co., Ltd.; the Bacillus megaterium powder was purchased from Foshan Sanzhong Environmental Protection Technology Co., Ltd. In the embodiments of the present invention, the composite bacterial nutrient is LB solid medium, and its preparation method is as follows: Dissolve tryptone, yeast extract and sodium chloride in water according to the mass ratio of 10:5:9, adjust the pH = 7.3 with sodium hydroxide aqueous solution, add agar powder and mix well, and make up the volume to obtain solution A; Take the obtained solution A, sterilize it by high pressure, and cool it to 45 - 50 °C to obtain solution B; Add the obtained solution B into a petri dish, adjust the wind speed to 1000 r / min, blow for 70 min, and seal the petri dish with a sterile sealing film to obtain LB solid medium.

[0033] In the present invention, the binder is sodium carboxymethyl cellulose.

[0034] In the embodiments of the present invention, the remaining reagents are all obtained by purchasing from the market.

[0035] Example 1 Preparation method of a soil conditioner for improving saline-alkali soil in Xinjiang region

[0036] S1. The preparation method of the water retention layer precursor is as follows: Add 10 parts of sodium polyglutamate to 30 parts of water, add 3 parts of kaolin to the obtained sodium polyglutamate solution, adjust the pH to 4 with phosphoric acid, add 4 parts of ethylene glycol diglycidyl ether, carry out a cross-linking reaction at 40 °C for 6 h to obtain polyglutamic acid-kaolin gel, cut and dry the obtained polyglutamic acid-kaolin gel (50 °C, 0.5 h), pulverize it and then add sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the total mass of sodium polyglutamate, kaolin and ethylene glycol diglycidyl ether to prepare the water retention layer precursor;

[0037] S2. The preparation method of the composite fertilizer layer precursor is as follows: Mix 40 parts of urea, 30 parts of potassium sulfate, 20 parts of diammonium phosphate, 50 parts of humic acid and 40 parts of gypsum, add sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the total mass of urea, potassium sulfate, diammonium phosphate, humic acid and gypsum, and adjust the pH to 7.5 to prepare the composite fertilizer layer precursor;

[0038] S3. The preparation method of the composite bacterial nutrient layer precursor is as follows: Mix 50 parts of composite bacterial nutrient and sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the mass of the composite bacterial nutrient to prepare the composite bacterial nutrient layer precursor;

[0039] S4. The preparation method of the microbial composite layer precursor is as follows: Mix 30 parts of Bacillus subtilis powder and 10 parts of Bacillus megaterium powder, add sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the total mass of Bacillus subtilis powder and Bacillus megaterium powder, and mix well to obtain the microbial composite layer precursor.

[0040] S5. Take 10 parts of the above-mentioned water-retaining layer precursor, 30 parts of the compound fertilizer layer precursor, 10 parts of the compound bacterial nutrient layer precursor, and 20 parts of the microbial composite layer precursor. At room temperature, granulate the microbial composite layer precursor as the inner core; wrap the compound bacterial nutrient layer precursor on the surface of the obtained inner core to obtain a secondary inner core; wrap the compound fertilizer layer precursor on the surface of the obtained secondary inner core to obtain a tertiary inner core; wrap the water-retaining layer precursor on the surface of the obtained tertiary inner core to obtain a soil conditioner for improving saline-alkali land in Xinjiang region.

[0041] Example 2 Preparation method of a soil conditioner for improving saline-alkali land in Xinjiang region

[0042] S1. The preparation method of the water-retaining layer precursor is as follows: Add 10 parts of sodium polyglutamate to 30 parts of water, add 5 parts of kaolin to the obtained sodium polyglutamate solution, adjust the pH to 4 with phosphoric acid, add 3 parts of polyethylene glycol diglycidyl ether, and carry out a cross-linking reaction at 60 °C for 10 h to obtain polyglutamic acid-kaolin gel. Cut and dry the obtained polyglutamic acid-kaolin gel (50 °C, 0.5 h), pulverize it, and then add a sodium carboxymethyl cellulose solution so that sodium carboxymethyl cellulose accounts for 2% of the total mass of sodium polyglutamate, kaolin, and ethylene glycol diglycidyl ether to prepare the water-retaining layer precursor;

[0043] S2. The preparation method of the compound fertilizer layer precursor is as follows: Mix 40 parts of urea, 30 parts of potassium sulfate, 20 parts of diammonium phosphate, 50 parts of humic acid, and 40 parts of gypsum, add a sodium carboxymethyl cellulose solution so that sodium carboxymethyl cellulose accounts for 2% of the total mass of urea, potassium sulfate, diammonium phosphate, humic acid, and gypsum, and adjust the pH to 7.5 to prepare the compound fertilizer layer precursor;

[0044] S3. The preparation method of the compound bacterial nutrient layer precursor is as follows: Mix 50 parts of compound bacterial nutrient with a sodium carboxymethyl cellulose solution so that sodium carboxymethyl cellulose accounts for 2% of the mass of the compound bacterial nutrient to prepare the compound bacterial nutrient layer precursor;

[0045] S4. The preparation method of the microbial composite layer precursor is as follows: Mix 30 parts of Bacillus subtilis powder and 10 parts of Bacillus megaterium powder, add a sodium carboxymethyl cellulose solution so that sodium carboxymethyl cellulose accounts for 2% of the total mass of Bacillus subtilis powder and Bacillus megaterium powder, and mix well to obtain the microbial composite layer precursor.

[0046] S5. Take 20 parts of the above-mentioned water-retaining layer precursor, 40 parts of the compound fertilizer layer precursor, 10 parts of the compound bacterial nutrient layer precursor, and 25 parts of the microbial composite layer precursor. At room temperature, granulate the microbial composite layer precursor as the inner core; wrap the compound bacterial nutrient layer precursor on the surface of the obtained inner core to obtain a secondary inner core; wrap the compound fertilizer layer precursor on the surface of the obtained secondary inner core to obtain a tertiary inner core; wrap the water-retaining layer precursor on the surface of the obtained tertiary inner core to obtain a soil conditioner for improving saline-alkali land in Xinjiang region.

[0047] Example 3 Preparation method of a soil conditioner for improving saline-alkali soil in Xinjiang region

[0048] S1. Preparation method of the water retention layer precursor: Add 10 parts of sodium polyglutamate to 30 parts of water, add 4 parts of kaolin to the obtained sodium polyglutamate solution, adjust the pH to 5 with phosphoric acid, add 8 parts of ethylene glycol diglycidyl ether, carry out a cross-linking reaction at 50 °C for 9 h to obtain polyglutamic acid-kaolin gel. Cut and dry the obtained polyglutamic acid-kaolin gel (50 °C, 0.5 h), and after pulverization, add a sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the total mass of sodium polyglutamate, kaolin and ethylene glycol diglycidyl ether to prepare the water retention layer precursor;

[0049] S2. Preparation method of the compound fertilizer layer precursor: Mix 40 parts of urea, 30 parts of potassium sulfate, 20 parts of diammonium phosphate, 50 parts of humic acid and 40 parts of gypsum, add a sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the total mass of urea, potassium sulfate, diammonium phosphate, humic acid and gypsum, and adjust the pH to 7.5 to prepare the compound fertilizer layer precursor;

[0050] S3. Preparation method of the compound bacterial fertilizer layer precursor: Mix 50 parts of compound bacterial fertilizer and a sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the mass of the compound bacterial fertilizer to prepare the compound bacterial fertilizer layer precursor;

[0051] S4. Preparation method of the microbial composite layer precursor: Mix 30 parts of Bacillus subtilis powder and 10 parts of Bacillus megaterium powder, add a sodium carboxymethyl cellulose solution so that the sodium carboxymethyl cellulose accounts for 2% of the total mass of Bacillus subtilis powder and Bacillus megaterium powder, and mix evenly to obtain the microbial composite layer precursor.

[0052] S5. Take 15 parts of the above water retention layer precursor, 20 parts of the compound fertilizer layer precursor, 10 parts of the compound bacterial fertilizer layer precursor and 30 parts of the microbial composite layer precursor. At room temperature, granulate the microbial composite layer precursor as the inner core; wrap the compound bacterial fertilizer layer precursor on the surface of the obtained inner core to obtain a secondary inner core; wrap the compound fertilizer layer precursor on the surface of the obtained secondary inner core to obtain a tertiary inner core; wrap the water retention layer precursor on the surface of the obtained tertiary inner core to obtain a soil conditioner for improving saline-alkali soil in Xinjiang region.

[0053] Comparative Example 1

[0054] S1 - S4 are the same as in Example 1;

[0055] S5. Take 10 parts of the above-mentioned water-retaining layer precursor, 30 parts of the compound fertilizer layer precursor, 10 parts of the compound bacterial nutrient layer precursor, and 20 parts of the microbial composite layer precursor. After mixing, add sodium carboxymethylcellulose solution so that sodium carboxymethylcellulose accounts for 2% of the total mass of the water-retaining layer precursor, the compound fertilizer layer precursor, the compound bacterial nutrient layer precursor, and the microbial composite layer precursor. At room temperature, make the above mixture into spherical particles to obtain a soil conditioner.

[0056] Comparative Example 2

[0057] S1 - S4 are the same as in Example 1;

[0058] S5. Take 10 parts of the above-mentioned water-retaining layer precursor, 30 parts of the compound fertilizer layer precursor, 10 parts of the compound bacterial nutrient layer precursor, and 20 parts of the microbial composite layer precursor. At room temperature, granulate the microbial composite layer precursor through a tablet press as the inner core; wrap the compound fertilizer layer precursor on the surface of the obtained inner core to obtain a secondary inner core; wrap the compound bacterial nutrient layer precursor on the surface of the obtained secondary inner core to obtain a tertiary inner core; wrap the water-retaining layer precursor on the surface of the obtained tertiary inner core to obtain a soil conditioner for improving saline-alkali land in Xinjiang region.

[0059] Performance test experiment:

[0060] The saline-alkali hazard of the experimental field soil is relatively serious (total salt 78.45 g / kg - 351 g / kg, pH value 8.76 - 9.5, organic matter content 7.688 g / kg - 16.316 g / kg), and the plot is flat and regular in shape. The test area is 6 hm 2 , with a total of 6 treatments, and the treatments are as follows: Treatment 1, CK (without using soil conditioner); Treatments 2 - 4, apply the soil conditioners prepared in Examples 1 - 3 to the soil; Treatments 5 - 6: apply the soil conditioners prepared in Comparative Example 1 - 2 to the soil. The basic situation of soil caking is shown in Table 1, and the total salt content of the soil is shown in Table 2.

[0061] Table 1 Percentage of soil particle size in each treatment group

[0062] > 2 mm 0.5 - 2 mm 0.25 - 0.5 mm < 0.25 mm Treatment group 1 78.89％ 19.59％ 0.65％ 0.87％ Treatment group 2 90.12％ 9.01％ 0.41％ 0.46％ Treatment group 3 89.05％ 10.15％ 0.45％ 0.35％ Treatment group 4 88.59％ 10.48％ 0.56％ 0.37％ Treatment group 5 80.39％ 18.56％ 0.59％ 0.56％ Treatment group 6 83.91％ 14.89％ 0.6％ 0.6％

[0063] As can be seen from Table 1, after treatment with the soil conditioner of the present invention (treatment groups 2 - 4), the aggregate content is mainly concentrated in > 2 mm. The < 0.25 mm, 0.25 - 0.5 mm, and 0.5 - 2 mm aggregate contents of treatment group 5 (Comparative Example 1), treatment group 6 (Comparative Example 2), and treatment group 1 (CK) are all higher than those treated with the soil conditioner of the present invention, proving that the soil conditioner prepared by the present invention affects the soil aggregate particle size distribution, improves the soil aggregate structure, and improves the soil physical properties.

[0064] Table 2

[0065]

[0066] Halostachys caspica belongs to the Chenopodiaceae family and has the characteristics of drought resistance, salt and alkali tolerance, and wind erosion and sand burial resistance. It is an excellent shrub for sand prevention and fixation, afforestation, and soil and water conservation, and is widely used in desertification control, saline-alkali land improvement, and the protection of desert highways. Its unique bio-ecological characteristics and extensive economic, medicinal, and ecological values. In the present invention, Halostachys caspica was planted in the above-mentioned sandy land improved by the soil conditioner prepared in Examples 1-3 and Comparative Examples 1-2 and the blank sandy land (CK, that is, without soil conditioner improvement) respectively, and the specific planting process is as follows:

[0067] 1) Seed germination promotion treatment: Select plump Halostachys caspica seeds, soak them in a constant temperature water of 30°C ± 1°C for 48 hours to allow the seeds to fully imbibe and complete germination promotion. After germination promotion, slight cracks appear on the seed surface, and the radicle shows signs of initial germination.

[0068] 2) Sowing: Select to sow in early April in spring when the soil temperature is stably maintained at 16°C - 25°C. The seedbed has a low-bed structure with a length of 6 m and a width of 2 m. Embankments are built around the seedbed, with a height of 25 cm ± 2 cm and a width of 50 cm ± 3 cm to form an independent irrigation unit. The seedbed is fully irrigated 24 hours before sowing to make the soil moisture content reach 85% - 90% of the field water holding capacity; transfer the germinated seeds to a perforated water container, and use a spraying device to evenly mix the seeds and water; use the strip sowing method to evenly spread the seeds together with water on the surface of the seedbed, and control the sowing density at 300 - 350 seeds / m 2 ; Immediately cover with disinfected fine sand, and strictly control the sand covering thickness at 1.0 - 1.5 cm, and lay a broken straw retaining layer on the surface to prevent water evaporation.

[0069] 3) Management during the emergence period: Maintain the soil moisture content in the 0 - 2 cm soil layer on the surface of the seedbed ≥ 65% through a micro-sprinkler irrigation system, regularly monitor the soil humidity daily and adjust the irrigation amount; use a bamboo rake to gently rake the seedbed surface every morning to break the hardening layer and keep the soil in a loose state; Temperature control: Adjust the seedbed temperature through a sunshade net to ensure a daily temperature of 22°C - 28°C and a night temperature not lower than 15°C.

[0070] Fifteen days after sowing the Halostachys caspica seeds, the emergence rate, plumule height, and radicle length were counted, and the results are shown in Table 3.

[0071] Table 3

[0072]

[0073] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A soil conditioner for improving saline-alkali soil in Xinjiang region, characterized in that, The soil conditioner is spherical, and from the outside to the inside, it is successively a water retention layer, a compound fertilizer layer, a compound bacterial nutrient layer, and a microbial composite layer.

2. The soil conditioner for improving saline-alkali soil in Xinjiang region according to claim 1, characterized in that The mass ratio of the water retention layer, the compound fertilizer layer, the compound bacterial nutrient layer, and the microbial composite layer is (1-2)∶(2-4)∶1∶(2-3).

3. A method for preparing a soil conditioner for improving saline-alkali land in Xinjiang region according to claim 1 or 2, characterized in that, It includes the following steps: Weigh the precursors of the water retention layer, the compound fertilizer layer, the compound bacterial nutrient layer, and the microbial composite layer according to the mass ratio; prepare the precursor of the microbial composite layer into granules as the inner core; wrap the precursor of the compound bacterial nutrient layer on the surface of the inner core to obtain a secondary inner core. Wrap the precursor of the compound fertilizer layer on the surface of the secondary inner core to obtain a tertiary inner core; wrap the precursor of the water retention layer on the surface of the tertiary inner core to obtain the soil conditioner for improving saline-alkali land in Xinjiang region.

4. The preparation method according to claim 3, wherein, The preparation method of the precursor of the microbial composite layer includes the following steps: mix the compound bacterial powder and the binder solution to obtain the precursor of the microbial composite layer.

5. The preparation method according to claim 3, characterized in that, The preparation method of the precursor of the compound bacterial nutrient layer includes the following steps: mix the compound bacterial nutrient and the binder solution to prepare the precursor of the compound bacterial nutrient layer.

6. The preparation method according to claim 3, characterized in that, The preparation method of the precursor of the compound fertilizer layer includes the following steps: mix urea, potassium sulfate, diammonium phosphate, humic acid, and gypsum, add the binder solution, and adjust the pH value to obtain the precursor of the compound fertilizer layer.

7. The preparation method according to claim 3, characterized in that, The preparation method of the precursor of the water retention layer includes the following steps: add kaolin to the sodium polyglutamate aqueous solution, adjust the pH to 4-5, add a cross-linking agent, and carry out a cross-linking reaction to obtain polyglutamic acid-kaolin gel. After crushing the polyglutamic acid-kaolin gel, add the binder solution to prepare the precursor of the water retention layer.

8. The preparation method according to claim 7, wherein The mass ratio of the sodium polyglutamate, kaolin, and the cross-linking agent is 1∶(0.3-0.5)∶(0.3-0.8).

9. The preparation method according to claim 7, wherein The temperature of the cross-linking reaction is 40-60°C, and the time is 6-10h.

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