A soda saline soil improvement material based on a sulfate-attapulgite composite, and a preparation method and application thereof

Abstract

This invention belongs to the field of soil environmental quality remediation technology, and discloses a soda saline-alkali soil improvement material based on a sulfate-attapulgite composite, its preparation method, and its application. The improver of this invention comprises a mineralizer and attapulgite in a mass ratio of 1-10:1, with the mineralizer being sulfate. The optimized ratio of sulfate and attapulgite was coupled as an improver, and soil cultivation experiments and pot experiments with Chinese cabbage were conducted to verify its improvement effect on soda saline-alkali soil. Experimental results demonstrate the effectiveness of this novel composite improver composed of sulfate mineralizer and attapulgite. This improver can simultaneously repair the physicochemical properties of saline-alkali soil and improve its adaptability to crops. In-situ mineralization and subsequent pot experiments verified the dual function of this improver in fixing salt and reducing alkali content.

Description

Technical Field

[0001] This invention relates to the field of soil environmental quality remediation technology, and in particular to a soda saline-alkali land improvement material based on sulfate-attapulgite composite, its preparation method and application. Background Technology

[0002] Soil salinization poses a significant threat, causing multifaceted damage. It leads to the disintegration of soil aggregates, resulting in pore blockage, reduced aeration and permeability, decreased soil structural stability, and lower nutrient content. The continuous expansion of saline-alkali land severely restricts the sustainable development of agriculture and forestry in my country. Soda saline-alkali soil is a typical type of saline-alkali soil, with soil salts primarily composed of Na₂CO₃ and NaHCO₃. Its high alkalinity results in poor soil structure, high bulk density, easy hardening, and low permeability, making it difficult to manage. Currently, methods for saline-alkali land management mainly fall into four categories: physical, chemical, biological, and integrated management. Physical improvement refers to engineering measures to improve saline-alkali soil, such as sand covering, micro-area soil improvement, and deep plowing. The basic principle is to cover the surface of saline-alkali land with loose, porous materials such as blast furnace slag, coal ash, and sand to suppress alkali and salt. However, this method is costly and cannot fundamentally change the nature of soil salinization. Biological soil amendment is based on the natural growth and metabolic activities of organisms such as plants or microorganisms. Through the absorption, transformation, and translocation of salts in the soil, it effectively reduces soil salinity and alkalinity. However, biological methods have long cycles, limited effectiveness, and are easily affected by climate, environment, and other factors. Chemical soil amendment mainly involves adding chemical substances to saline-alkali soils that need improvement. Currently, widely used amendments include vinegar residue, humic acid, phosphogypsum, superphosphate, peat, and slag. During the amendment process, ion exchange occurs in the soil, reducing the absorption of sodium by soil colloids. + The adsorption of these substances reduces soil dispersion and regulates soil pH, ultimately decreasing soil salinity. Among numerous chemical amendments, desulfurized gypsum and aluminum sulfate are widely used due to their significant improvement effects. Desulfurized gypsum, whose main component is calcium sulfate, improves soil structure by replacing sodium ions on soil colloids with calcium ions, and is widely used in saline-alkali soil improvement. Chemical amendment methods have become the mainstream method for saline-alkali land management due to their low cost, ease of operation, and ability to fundamentally address soil salinity.

[0003] Attapulgite is frequently used in catalysis and energy storage. In catalysis, due to its unique porous structure, attapulgite can enhance reaction rates in chemical reactions, and its stable structure makes it suitable as a catalyst support to optimize catalytic processes. Attapulgite has more nanopores than zeolites, a surface rich in Si-OH groups, a large specific surface area, good plasticity and binding properties, and also exhibits cation exchange capacity, water absorption, and adsorption / decolorization properties, making it commonly used in the preparation of adsorbent materials. After modification, the adsorption capacity of attapulgite can be significantly improved, allowing it to adsorb various harmful substances. Attapulgite is also used for the remediation of saline-alkali soils; existing technologies disclose the combination of attapulgite with traditional fertilizers, effectively improving the soil's water and fertilizer retention capacity. However, the direct effect of attapulgite on reducing soil salinity and alkalinity has not yet been studied.

[0004] Layered double hydroxides (LDHs) are a class of layered clay materials with anion exchange capacity, and their general chemical formula can be represented as [M]. 2+ 1-x M 3+ x (OH)2] x+ A n- x / n·mH2O, where M 2+ and M 3+ A consists of divalent and trivalent metal cations, occupying octahedral sites in the brucite-like lamellae. n- These are interlayer anions used to balance the M... 3+ The positive charge generated by the substitution. This type of material in M... 2+ / M 3+ The types, proportions, and types of interlayer anions are highly adjustable, allowing for flexible control of their structure and properties. A core characteristic of LDHs is the positive charge on their layers and the exchangeability of interlayer anions; among them, CO32-... 2- It typically exhibits a particularly strong affinity for interlayer sites, readily displacing weakly binding anions (such as SO42-). 2- or Cl - This characteristic also provides conditions for the fixation of carbonates. These materials offer high flexibility in the selection of metal ion types, ratios, and interlayer anions, thus allowing for the control of their physicochemical properties.

[0005] LDHs have been widely used in photoelectric and catalysis fields, and are also used in soil remediation, showing great potential, especially in the adsorption and fixation of heavy metals (such as Cd, Pb, and Zn) and anionic pollutants (such as iodates and nitrates). Traditionally, LDHs used for soil improvement are mostly synthesized in the laboratory via co-precipitation, requiring an OH- atmosphere. - and specific interlayer anions (such as CO3) 2-SO4 2- Prepared under conditions where OH- (etc.) are present. However, in natural soil systems, especially those rich in OH-, [the process is less efficient]. - and CO3 2- In soda-saline-alkali soils, the introduction of exogenous divalent and trivalent metal salts may induce in-situ formation of LDHs, thus providing a new approach for soil improvement. Although previous studies have reported the in-situ formation potential of CaFe-LDH combined with attapulgite in saline-alkali soils, systematic research on the formation conditions, stability, and improvement effects of LDHs in real alkaline-saline soils is still lacking and warrants further in-depth exploration. Summary of the Invention

[0006] The purpose of this invention is to provide a soda saline-alkali land improvement material based on sulfate-attapulgite composite, its preparation method and application, thereby solving the above-mentioned problems existing in the prior art.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, comprising the following raw materials: mineralizer and attapulgite; The mass ratio of the mineralizer to attapulgite is 1~10:1; The mineralizing agent is a sulfate.

[0008] Preferably, the mineralizing agent is a mixture of a first acidic metal salt and a second acidic metal salt; the first acidic metal salt is calcium sulfate; and the second acidic metal salt is aluminum sulfate or ferric sulfate.

[0009] Preferably, the molar ratio of the first acidic metal salt to the second acidic metal salt is 1 to 3:1.

[0010] This invention also provides a method for preparing a soda saline-alkali land improvement material based on a sulfate-attapulgite composite, comprising the following steps: Mineralizing agent and attapulgite are mixed to obtain soda saline-alkali land improvement material based on sulfate-attapulgite composite.

[0011] This invention also provides an application of a soda saline-alkali soil improvement material based on sulfate-attapulgite composite in the remediation and treatment of moderate to severe soda saline-alkali soil.

[0012] Preferably, the mineralizing agent has a mass fraction of 0.1-1% in the moderately to severely soda-salt-alkali soil; and the attapulgite has a mass fraction of 0.1% in the moderately to severely soda-salt-alkali soil.

[0013] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: This invention proposes a soda-saline-alkali soil improvement material based on a sulfate-attapulgite composite. An optimized ratio of sulfate and attapulgite is coupled as a conditioner, and soil culture experiments and pot experiments with Chinese cabbage were conducted to verify its improvement effect on soda-saline-alkali soil. Experimental results demonstrate the effectiveness of this novel composite conditioner composed of sulfate mineralizer and attapulgite. This conditioner can simultaneously repair the physicochemical properties of saline-alkali soil and improve its adaptability to crops. In-situ mineralization and subsequent pot experiments verified the dual function of this conditioner in fixing salt and reducing alkali content. The experimental results also confirmed that the application of the composite conditioner rapidly initiates the in-situ mineralization process within the saline-alkali soil. Within 150 days, XRD, SEM / TEM, and FTIR analyses confirmed the formation of the CaAl-LDH structure. During the formation of CaAl-LDH, OH... - and CO3 2- The fixation effect makes free OH- - and CO3 2- The soil is transformed into a stable state, thereby reducing soil alkalinity. The metal salt components in the applied mineralizer are also fixed to varying degrees due to their participation in LDH synthesis, with a decrease in water-soluble calcium, magnesium, aluminum, and iron ions. Furthermore, the cation exchange capacity of attapulgite is enhanced under the action of CaSO4, allowing Al and Mg ions released from attapulgite to replace Na ions in saline-alkali soils through cation exchange. Continuous calcium and aluminum extraction experiments also confirmed the role of CaAl-LDH formation in salt fixation. In addition, this amendment showed a positive effect on soil organic matter (SOM) dynamics, enhancing its retention capacity in simulated leaching (stable SOM increased from 5.14 g / kg to 6.81 g / kg), indicating potential benefits for soil carbon stability and overall soil health. Crucially, pot experiments confirmed the practicality and synergistic benefits of this method. Pakchoi planted immediately after application of the soil conditioner showed significantly increased germination rate, plant height (600% increase compared to the control), and leaf area (125% increase compared to the control) during the seedling stage. This indicates that the compound soil conditioner can rapidly improve soil conditions and promote plant growth, bypassing the potential waiting period associated with traditional chemical remediation strategies. The active uptake of released nutrients by plants also mitigated the increase in soil organic matter (EC) observed under non-crop conditions. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0015] Figure 1The images show the soil sample characterization of the in-situ mineralization experiments of the amendments in Examples 1-5; where a is the XRD pattern of soil samples at different mineralization times, b is the XRD pattern of LDHs in soil samples at different mineralization times, c is the FTIR pattern of soil samples at different mineralization times, d is the SEM pattern of LDHs in soil samples after 5 months of mineralization, e is the EDS pattern of LDHs in soil samples after 5 months of mineralization, f is the elemental content pattern of LDHs in soil samples after 5 months of mineralization, g is the TEM image of LDHs in soil samples after 5 months of mineralization, h is the HRTEM image of LDHs in soil samples after 5 months of mineralization at a 10 nm scale, and i is the HRTEM image of LDHs in soil samples after 5 months of mineralization at a 5 nm scale. Figure 2 The soil organic matter content in the in-situ mineralization experiment of the amendment in Example 5; Figure 3 The diagram shows the physicochemical properties of soil samples from the in-situ mineralization experiments of the soil amendments in Examples 1-5; where a represents the change in soil pH and b represents the change in CO3. 2- The change in concentration, where c is the water-soluble Na + The change, d is the water-soluble Ca 2+ The change, e is water-soluble Mg 2+ The change, f is the water-soluble Al 3+ The change, g is water-soluble Fe 3+ Changes; Figure 4 A schematic diagram illustrating the potted plant results of a bok choy crop experiment. Figure 5 Figure 1 shows the physicochemical properties of soil samples from in-situ mineralization experiments using soil amendments in Comparative Examples 1-5; where a represents soil pH and b represents CO3. 2- Concentration, c is conductivity, d is water-soluble Na + e is water-soluble Mg 2+ f is water-soluble Ca 2+ ; Figure 6 The diagram shows the physicochemical properties of soil samples from the in-situ mineralization experiments of the amendments in Examples 6-10; where a represents the change in soil pH, and b represents the change in water-soluble Na+. + The change, c is CO3 2- The change in concentration, d represents the concentration of water-soluble Mg. 2+ The change, e is water-soluble Ca 2+ The change, f is water-soluble Fe 3+ The changes. Detailed Implementation

[0016] This invention provides a soda saline-alkali land improvement material based on a sulfate-attapulgite composite, comprising the following raw materials: mineralizer and attapulgite.

[0017] In this invention, the mineralizing agent is preferably a sulfate.

[0018] In this invention, the mass ratio of the mineralizer to attapulgite is preferably 1 to 10:1, more preferably 2 to 8:1, and even more preferably 2:1.

[0019] In this invention, the mineralizing agent is preferably a mixture of a first acidic metal salt and a second acidic metal salt; the first acidic metal salt is preferably calcium sulfate; the second acidic metal salt is preferably aluminum sulfate or ferric sulfate, and more preferably aluminum sulfate.

[0020] In this invention, the molar ratio of the first acidic metal salt and the second acidic metal salt is preferably 1 to 3:1, more preferably 2 to 3:1, and even more preferably 2:1.

[0021] This invention also provides a method for preparing a soda saline-alkali land improvement material based on a sulfate-attapulgite composite, comprising the following steps: Mineralizing agent and attapulgite are mixed to obtain soda saline-alkali land improvement material based on sulfate-attapulgite composite.

[0022] This invention also provides an application of a soda saline-alkali soil improvement material based on sulfate-attapulgite composite in the remediation and treatment of moderate to severe soda saline-alkali soil.

[0023] In this invention, the mass fraction of the mineralizing agent in moderately to severely soda saline-alkali soil is preferably 0.1-1%, more preferably 0.2-0.7%, and even more preferably 0.2%; the mass fraction of the attapulgite in moderately to severely soda saline-alkali soil is preferably 0.1%.

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, comprising the following raw materials: Attapulgite and mineralizer in a mass ratio of 1:1; the mineralizer is CaSO4 and Al2(SO4)3 in a molar ratio of 1:1.

[0027] Example 2

[0028] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, comprising the following raw materials: Attapulgite and mineralizer in a mass ratio of 1:1; the mineralizer is CaSO4 and Al2(SO4)3 in a molar ratio of 2:1.

[0029] Example 3

[0030] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, comprising the following raw materials: Attapulgite and mineralizer in a mass ratio of 1:1; the mineralizer is CaSO4 and Al2(SO4)3 in a molar ratio of 3:1.

[0031] Example 4

[0032] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, comprising the following raw materials: Attapulgite and mineralizer in a mass ratio of 1:2; the mineralizer is CaSO4 and Al2(SO4)3 in a molar ratio of 2:1.

[0033] Example 5

[0034] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, comprising the following raw materials: Attapulgite and mineralizer in a mass ratio of 1:3; the mineralizer is CaSO4 and Al2(SO4)3 in a molar ratio of 2:1.

[0035] In-situ mineralization experiment

[0036] 20g of soda saline-alkali soil sample was added to a 100mL plastic cup, and the amendments from Examples 1-5 were added respectively, i.e., 5 treatment groups, denoted as T1-T5; at the same time, a blank control group (without amendment) was set up, denoted as CK. The setup of the 5 treatment groups and 1 blank control group is shown in Table 1. The amendment was thoroughly mixed into the soda saline-alkali soil by mechanical stirring (stirring with a scraper for 5 minutes) until it was visually uniform and the surface was slightly smooth. After flattening the surface, 5g of water was added at a water-to-soil mass ratio of 1:4 to promote the dissolution of the mineralizer and ensure that it fully contacts the water-soluble ions in the soda saline-alkali soil. Then it was placed near a window to maintain the temperature consistent with the local temperature. In the following experiments, water was added in a timely manner according to the soil moisture content of 10%. On the subsequent days of 3, 7, 14, 21, 30, 60, 90, 120, and 150, soil samples were collected using the sacrificial method, air-dried, and subjected to physicochemical analysis and characterization.

[0037] Table 1. Setup of 5 treatment groups and 1 blank control group

[0038] The soil sample characterization results of the in-situ mineralization experiments of the amendments in Examples 1-5 are as follows: Figure 1As shown. By Figure 1 It can be seen that the application of the modifier of this invention rapidly initiates the in-situ mineralization process in saline-alkali land. Within 150 days, the formation of the CaAl-LDH structure was confirmed by XRD, SEM / TEM, and FTIR analysis. During the formation of CaAl-LDH, OH... - and CO3 2- The fixation effect makes free OH- - and CO3 2- The soil is transformed into a stable state, thereby reducing soil alkalinity. The metal salt components in the applied mineralizing agent are also fixed to varying degrees due to their participation in the synthesis of LDHs, with a decrease in water-soluble calcium, magnesium, aluminum, and iron ions. Furthermore, under the action of CaSO4, the cation exchange capacity of ATP clay is enhanced, and Al and Mg ions released from attapulgite can replace Na ions in saline-alkali soil through cation exchange. Continuous extraction experiments of calcium and aluminum also confirmed the role of CaAl-LDH formation in salt fixation. In addition, the soil organic matter content in the in-situ mineralization experiment of the amendment in Example 5 was as follows... Figure 2 As shown, by Figure 2 It can be seen that the amendment has a positive effect on soil organic matter (SOM) dynamics, enhancing its retention capacity in simulated leaching (stable SOM increased from 5.14 g / kg to 6.81 g / kg), indicating potential benefits for soil carbon stability and overall soil health.

[0039] The physicochemical properties of soil samples from the in-situ mineralization experiments of the amendments in Examples 1-5 are as follows: Figure 3 As shown. By Figure 3 It is evident that the application of the soil conditioner of this invention leads to substantial improvement in key soil chemical properties. Soil pH decreased significantly, from a highly alkaline 10.6 in the control group to a near-neutral 7.9, a reduction of 2.7 pH units; soil carbonate ion concentration decreased from 4.1 g / kg in the control group to 0.7 g / kg in the improved soil (a decrease of 83%); water-soluble calcium ion concentration decreased from 66 mg / kg to 22 mg / kg, a decrease of 67%; magnesium ion concentration decreased from 177 mg / kg to 28 mg / kg, a decrease of 84%; aluminum ion concentration decreased by 85%; and iron ion concentration decreased by 86%. The water-soluble sodium content in the treated group increased by 9-290% compared to the control group, indicating that more colloidal sodium was replaced, and combined with leaching, this fundamentally solves the problem of high alkalinity.

[0040] Experiment with Chinese cabbage crop

[0041] In the pot cultivation experiment, opaque plastic pots (size: 1 gallon) were selected, and each pot was filled with 1.0 kg of soda saline-alkali soil. Three treatment groups were established, with three replicate pots in each group: (1) control, denoted as CK, with only 1000 g of prepared soil; (2) attapulgite soil (ATP) only, denoted as ATP, 1000 g of soil + 1.0% w / w (10 g) of ATP; (3) soil conditioner, denoted as CA, 1000 g of soil + 1.0% w / w (10 g, calcium sulfate and aluminum sulfate molar ratio 2:1) mineralizer + 1.0% w / w (10 g) of ATP. Chinese cabbage seeds were sown in the pots, with 9 live Chinese cabbage seeds sown at equal intervals in each pot, buried shallowly at a depth of ~0.5 cm. Evapotranspiration loss was replenished by watering daily (about 4 mL / day, adjusted as needed based on visual observation or pot weight), and soil moisture was maintained near the optimal level. The entire experiment was conducted in a greenhouse with a daytime temperature of 25℃ and a nighttime temperature of 20℃. At the end of the experiment (day 24), plant growth was assessed by measuring germination rate (%), average plant height (cm), and average number of leaves. The results are shown in Table 2. Figure 4 As shown. After crop harvest, soil samples were collected from each pot and key physicochemical properties (pH, EC, CO3) were analyzed. 2- To assess soil conditions after planting, the results are shown in Table 3.

[0042] Table 2. Effects of different treatments on the growth of Chinese cabbage in a pot experiment (after 24 days).

[0043] Table 3. Effects of different treatments on the physicochemical properties of saline-alkali soil in pot experiments (after 24 days)

[0044] Adding ATP alone moderately increased the germination rate to 42%, suggesting an association with improved or slightly improved water retention. The amendant (CA) treatment also significantly increased the germination rate compared to the control. Post-germination growth assessment highlighted the more pronounced effects of the treatments. Although the ATP treatment had limited growth-promoting effects (average plant height 1.3 cm, average number of leaves 3), this was not significantly different from the control group (average plant height 1.1 cm, average number of leaves 3), indicating that ATP alone is insufficient to overcome severe salt-alkali stress. In contrast, the amendant (CA) treatment significantly promoted all aspects of plant growth. Morphologically, it promoted plant growth (…). Figure 4The improvements were as follows: average plant height (3.5 cm, 218% increase over control) and average number of leaves (5 leaves, 67% increase over control). Importantly, these morphological improvements led to a significant increase in biomass. The total fresh weight of plants treated with CA (0.71 g) was 70% higher than that of plants treated with CK (0.21 g), providing further evidence that CA promotes growth. Figure 4 Visual observation of the plants showed that, compared to sparsely stressed plants under CK and ATP treatments, plants treated with CA were greener and had more complete root, stem, and leaf development, providing intuitive and quantifiable evidence for improved plant health. Analysis of the soil physicochemical properties after bok choy harvest further clarified the effectiveness of the amendment under planting conditions (Table 3). Even under conditions of active plant growth, the application of the amendment resulted in a significant decrease in soil pH and carbonate content. Soil pH decreased from an initial 10.2 to 7.4 in the amended pot, a reduction of 27%. Similarly, CO3... 2- The content of [unspecified substance] decreased sharply from 3.5 g / kg (control) to 0.83 g / kg, a decrease of 76%. This is consistent with the results of the in-situ mineralization experiment. Due to the addition of soluble salts, the EC of the improved potted soil after harvest (2.1 mS / cm) was higher than that of the post-harvest control (1.3 mS / cm), but importantly, the increase was less significant compared to the in-situ mineralization experiment (EC reached 2.5 mS / cm). This indicates that under natural drainage and long growing seasons in the field, EC is expected to decrease further with salt utilization or leaching.

[0045] Comparative Examples 1-5

[0046] 20g of soil was placed in a 100mL plastic cup. One blank group and five control groups were set up. The blank group received no soil amendment, while the other five control groups received different amendment components (calcium sulfate, aluminum sulfate, ATP, calcium sulfate + ATP, aluminum sulfate + ATP) at 0.1% of the soil mass fraction, as shown in Table 4. All other experimental procedures followed the methods described in the "In-situ Mineralization Experiment". Soil samples were collected on day 30 of the experiment to measure soil pH, electrical conductivity (EC), and CO3. 2- Concentration and soluble Na + Mg 2+ and Ca 2+ Concentration, each measurement was repeated three times. Results are as follows: Figure 5 As shown.

[0047] Table 4. Setup of one blank group and five control groups

[0048] Depend on Figure 5It can be seen from the comparative experiment that, under the same addition amount and within the same time period, the improvement effect of adding sulfate and attapulgite alone is far less than that of the composite amendment with optimized ratio.

[0049] Example 6

[0050] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, as detailed in Embodiment 1, except that Al2(SO4)3 is replaced with Fe2(SO4)3.

[0051] Example 7

[0052] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, as detailed in Embodiment 2, except that Al2(SO4)3 is replaced with Fe2(SO4)3.

[0053] Example 8

[0054] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, as detailed in Embodiment 3, except that Al2(SO4)3 is replaced with Fe2(SO4)3.

[0055] Example 9

[0056] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, as detailed in Embodiment 4, except that Al2(SO4)3 is replaced with Fe2(SO4)3.

[0057] Example 10

[0058] This embodiment provides a soda saline-alkali land improvement material based on sulfate-attapulgite composite, as detailed in Embodiment 5, except that Al2(SO4)3 is replaced with Fe2(SO4)3.

[0059] Based on the aforementioned in-situ mineralization experiments, the setup of 5 treatment groups and 1 blank control group is shown in Table 5. The physicochemical properties of the soil samples from the in-situ mineralization experiments of the amendments in Examples 6-10 are as follows: Figure 6 As shown.

[0060] Table 5. Setup of 5 treatment groups and 1 blank control group

[0061] Depend on Figure 6It is evident that the application of the soil conditioner of this invention leads to substantial improvement in key soil chemical properties. Soil pH decreased significantly, from a high alkalinity of 10.6 in the control group to a minimum of 8.6, a reduction of 2 pH units; soil carbonate ion concentration decreased from 4.1 g / kg in the control group to 0.5 g / kg in the improved soil (a decrease of 88%); water-soluble calcium ion concentration decreased from 15 mg / kg to 2 mg / kg, a decrease of 86%; magnesium ion concentration decreased from 150 mg / kg to 1 mg / kg, a decrease of 99%; aluminum ion concentration decreased by 99%; and iron ion concentration decreased by 98%. The water-soluble sodium content in the treated group increased by 9-95% compared to the control group, indicating that more colloidal sodium was replaced, and combined with leaching, this fundamentally solves the problem of high alkalinity.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A soda-saline soil improvement material based on a sulfate-attapulgite complex, characterized in that, The soda saline soil improvement material based on the sulfate-attapulgite composite comprises the following raw materials: a mineralizer and attapulgite. The mass ratio of the mineralizer to the attapulgite is 1-10:

1. The mineralizer is a sulfate.

2. The soda-saline soil improvement material based on a sulfate-attapulgite complex according to claim 1, characterized in that, The mineralizer is a mixture of a first acidic metal salt and a second acidic metal salt; the first acidic metal salt is calcium sulfate; and the second acidic metal salt is aluminum sulfate or iron sulfate.

3. The soda-saline soil improvement material based on a sulfate-attapulgite complex according to claim 2, characterized in that, The molar ratio of the first acidic metal salt to the second acidic metal salt is 1-3:

1.

4. A method for preparing a soda-saline soil amelioration material based on a sulfate-attapulgite complex according to any one of claims 1 to 3, characterized in that, The soda saline soil improvement material based on the sulfate-attapulgite composite comprises the following steps: The mineralizer and the attapulgite are mixed to obtain the soda saline soil improvement material based on the sulfate-attapulgite composite.

5. The use of the soda saline soil improvement material based on the sulfate-attapulgite composite in the repair and treatment of moderate-to-severe soda saline soil.

6. Use according to claim 5, characterized in that, The mass fraction of the mineralizer in the moderate-to-severe soda saline soil is 0.1-1%; and the mass fraction of the attapulgite in the moderate-to-severe soda saline soil is 0.1%.

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