A saline-alkali soil composite improvement conditioner and an in-situ repair cultivation method thereof

Abstract

This invention discloses a composite soil conditioner for saline-alkali land and its in-situ remediation cultivation method, belonging to the field of soil ecological restoration technology. The conditioner comprises a calcium-based replacement modification component, an organic chelate acid-regulating component, a porous mineral salt-fixing component, a salt-tolerant microbial remediation component, and a polyamino acid nutrient activating component. The calcium-based component undergoes low-temperature activation treatment, and the porous minerals undergo high-temperature pore-forming modification. These components synergistically constitute a five-in-one remediation system integrating ion replacement, organic acid regulation, physical salt fixation, microbial reconstruction, and nutrient activation. The accompanying in-situ remediation method includes site pretreatment, quantitative application of the conditioner according to salinity level, layered composite tillage combining shallow rotary tillage and deep loosening, multiple gradient leaching, and in-situ steady-state maintenance. This invention can achieve long-term in-situ remediation of saline-alkali land, reducing soil pH and soluble salt content, increasing the proportion of aggregate structure, effectively inhibiting salinity rebound, and is suitable for differentiated management of light, medium, and severe saline-alkali land.

Description

Technical Field

[0001] This invention relates to the field of soil ecological restoration technology, specifically to a compound conditioner for improving saline-alkali land and its in-situ remediation cultivation method. Background Technology

[0002] Saline-alkali arable land resources are widely distributed and complex in type, such as soda saline-alkali soil in the Songnen Plain, saline soil in inland irrigation areas, and saline-alkali land in plains and coastal tidal flats. These lands generally suffer from multiple soil obstacles, including enrichment of exchangeable sodium ions, high pH values, accumulation of soluble salts, soil compaction and hardening, lack of aggregate structure, imbalance of soil microbial communities, and loss of micronutrient retention. Salinity stress leads to poor land tilth, low productivity, and low multiple cropping index, severely restricting high-quality regional agricultural development and the ecological stability of arable land.

[0003] The existing saline-alkali land improvement technology system has obvious technical shortcomings. The mainstream improvement methods mostly adopt single material improvement or single leaching process, which lacks adaptability and long-term effectiveness: traditional calcium-based improvement materials can only achieve simple sodium-calcium replacement and do not have the functions of acid adjustment chelation, salt fixation and soil conservation, and ecological restoration; single organic matter improvement materials can only loosen the soil slightly and cannot solve the problem of sodium ion enrichment in soil colloids and deep salt return from the root; conventional tillage is mostly shallow plowing and mixing, which cannot break the water- and salt-blocking structure of the plow pan, and the salt only migrates back and forth in the surface layer, making it very easy for salt and alkali to return quickly after improvement.

[0004] Meanwhile, existing large-scale remediation methods largely rely on engineering approaches such as topsoil replacement, off-site removal of saline-alkali soil, and large-scale flood irrigation and drainage. These methods suffer from problems such as large engineering workload, high treatment costs, damage to the original soil structure, and a high risk of secondary soil erosion, making it difficult to achieve low-cost, in-situ, and long-term remediation of large areas of saline-alkali farmland. Furthermore, existing improvement technologies lack a tiered and adaptable treatment system, failing to provide differentiated treatment for plots with varying degrees of salinity (mild, moderate, and severe), and generally exhibiting the technical drawbacks of over-improvement for mild cases and under-improvement for severe cases.

[0005] In summary, existing saline-alkali land improvement technologies generally suffer from technical defects such as single function, shallow restoration dimension, poor improvement stability, limited adaptability to different scenarios, easy salinity rebound, and high treatment costs. There is an urgent need to develop a composite improvement system with multiple mechanisms working together, stratified and precise treatment, and in-situ long-term restoration, along with supporting farming techniques. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a compound soil conditioner and its in-situ remediation cultivation method for saline-alkali land. This method utilizes low-temperature activation of calcium-based replacement components and high-temperature pore-forming porous mineral components, coupled with organic chelation, microbial remediation, and polyamino acid nutrient activation to construct a five-in-one synergistic remediation system. Combined with graded and quantitative application, layered three-dimensional cultivation, and multi-stage gradient leaching in-situ remediation processes, this method solves the problems of traditional soil improvement technologies, such as single function, insufficient improvement depth, salt residue rebound, poor adaptability, and high treatment costs. It achieves in-situ, multi-dimensional, long-term, and standardized remediation and treatment of saline-alkali land.

[0007] This invention provides the following technical solution: The present invention provides a compound conditioning agent for saline-alkali land, which, by weight, comprises the following functional components: 35-55 parts of calcium-based replacement modified component 20-30 parts of organic chelated acid-regulating component 15-25 parts of porous mineral salt-fixing components Salt-tolerant microbial remediation component 3-8 parts 2-5 parts of polyamino acid nutrient activating component.

[0008] The calcium-based replacement modification component is a composite powder of desulfurized gypsum and shell powder in a mass ratio of 2 to 3:1, with a particle size of 80 to 120 mesh and an effective calcium ion content of not less than 22 wt%. The calcium-based replacement modified component is activated at a low temperature of 120-150℃ for 30-45 minutes, which significantly increases the degree of calcium ion ion release. It is used to efficiently replace adsorbed sodium ions on the surface of soil colloids, thereby eliminating the core causes of soil alkalization and compaction from the root.

[0009] The organic chelated acid-regulating component is a compound system of humic acid and fulvic acid with a mass ratio of 1.5 to 2:1, and the total organic matter content is not less than 60 wt%. It can accurately neutralize the alkaline ions of carbonate and bicarbonate in the soil, steadily reduce and stabilize the soil pH value, and at the same time chelate and passivate harmful heavy metal ions in the soil, thus having the dual functions of acidification and soil improvement and safe soil remediation.

[0010] The porous mineral solid salt component is a composite powder of zeolite and attapulgite in a mass ratio of 1:1 to 1.5, prepared by ultrafine grinding combined with high-temperature pore-forming modification, with a specific surface area of ​​not less than 180 m². 2 / g, with a porosity of not less than 45%, it can efficiently adsorb free soluble salts in the soil, block the capillary salt return channels in the soil, and inhibit the surface accumulation and rebound of salts.

[0011] The salt-tolerant microbial remediation component is a compound bacterial agent consisting of Bacillus subtilis and Bacillus amyloliquefaciens in a 1:1 ratio of viable bacteria, with a total effective viable bacteria count of not less than 2.0 × 10⁻⁶. 9It can stably establish and reproduce in high-salt and high-alkali rhizosphere environments, reconstruct unbalanced soil microbial communities, optimize rhizosphere microecology, and achieve long-term biological salt fixation and alkali stabilization.

[0012] The polyamino acid nutrient activating component is a mixture of polyaspartic acid and polyglutamic acid, which can effectively remove the solidified and passivated state of trace elements such as phosphorus, iron, and zinc in soil under high salinity and alkalinity, activate the inherent nutrients in the soil, and improve the basic fertility of arable land.

[0013] The functional components work synergistically and complement each other to construct a five-in-one composite remediation system that integrates ion exchange dealkalization, physical adsorption and salt fixation, organic acidification and chelation, nutrient activation and fertilizer enhancement, and microbial ecological reconstruction. This system overcomes the technical shortcomings of traditional single-material remediation, which has a single dimension of remediation, short-term effects, and easy rebound.

[0014] This invention also provides a method for in-situ remediation of saline-alkali land, which uses the aforementioned compound soil conditioner for in-situ remediation without the addition of new soil, and includes the following steps: S1. Site pretreatment: Remove surface stubble and weeds, level the site, fully dredge the field irrigation and drainage system, construct a continuous and unobstructed longitudinal salt leaching and drainage channel, eliminate dead spots of water and salt accumulation, and provide basic conditions for the complete migration of salt from the topsoil.

[0015] S2. Graded and quantitative application: Apply the pesticide precisely according to the different levels of saline-alkali land. Apply 40-60 kg of conditioner per mu for mild saline-alkali land, 70-90 kg per mu for moderate saline-alkali land, and 100-120 kg per mu for severe saline-alkali land to ensure that the conditioner evenly covers the entire surface.

[0016] S3. Layered compound tillage: A three-dimensional tillage mode combining shallow rotary tillage and deep loosening is adopted. Rotary tillage is carried out at a speed of 200-250 r / min for 20-25 cm to homogeneously mix the conditioner with the 0-25 cm tillage layer soil, with a mixing uniformity of not less than 90%. Then, deep loosening is carried out for 30-60 cm to break up the dense salt-blocking plow layer of saline-alkali land and construct a three-dimensional salt leaching channel that runs through the tillage layer.

[0017] S4. Staged gradient leaching: Within 24 hours of tillage completion, perform the first saturated irrigation with fresh water with a mineralization of ≤1g / L, with an irrigation volume of 30-40m³. 3 / mu, rapidly driving the sodium-calcium replacement reaction to proceed fully; leaching salt with secondary irrigation every 7-10 days, with an irrigation volume of 15-20m³. 3 / acre, thoroughly remove residual free salts from the topsoil; the entire process adopts a slow-seepage flood irrigation mode, controlling the water flow speed to ≤0.5m / s, to avoid soil erosion and localized accumulation of chemicals.

[0018] S5. In-situ stable maintenance: After salt leaching, allow the soil to dry naturally for 3-5 days to avoid disturbing the deep soil layers, preserve the complete salt leaching channels and soil structure, and combine with straw return to the field to continuously maintain the soil aggregate structure and achieve long-term salt control and alkali stabilization.

[0019] The core technical principle of this invention is as follows: This invention achieves efficient sodium-calcium replacement dealkali removal through modified calcium-based components, stabilizes acidity and reduces alkali and passesivates ions through organic chelating components, physically fixes and inhibits salt through multi-level pore-forming mineral components, reconstructs the rhizosphere microecology through salt-tolerant microbial components, and activates soil nutrients through polyamino acid components. Simultaneously, it incorporates a complete set of tillage techniques including differentiated pesticide application, layered salt breaking and drainage, gradient salt leaching and desalination, and in-situ stable maintenance. This multi-dimensional approach simultaneously improves soil chemical properties, physical structure, microecological environment, and nutrient supply capacity, achieving long-term, non-rebounding restoration of saline-alkali land.

[0020] The beneficial effects achieved by the present invention using the above technical solution are as follows: 1. By constructing a five-in-one synergistic remediation system integrating modified calcium-based dealkali removal, organic chelation acidification, mineral porous salt fixation, microbial ecological restoration, and polyamino acid nutrient activation, the system solves the problems of traditional amendment materials having single function and limited remediation dimensions, and simultaneously addresses multiple obstacles in saline-alkali land such as salt damage, alkali damage, compaction, nutrient failure, and microecological imbalance.

[0021] 2. By performing specialized modification treatment on calcium-based components and porous mineral components, the free activity of calcium ions and the adsorption capacity of mineral pores are enhanced, thereby improving the sodium-calcium replacement efficiency and salt suppression and fixation capacity from the root, and solving the defects of traditional modification technology such as easy salt return and poor stability.

[0022] 3. By adopting a layered compound tillage and multi-stage gradient leaching process, the shortcomings of insufficient improvement depth in traditional shallow tillage are solved, and the salt is completely removed through two-stage gradient irrigation.

[0023] 4. By adopting a graded and precise application system, it can be used to treat mild, moderate and severe saline-alkali land differently. It is suitable for multiple types of saline-alkali land, including soda type, sulfate type and chloride type, and can be applied on a large scale.

[0024] 5. This plan adopts the in-situ soil remediation model throughout the process, without the need for soil replacement or transportation of saline-alkali soil. It involves a small amount of engineering work, low treatment costs, and does not damage the original farmland structure. Combined with microbial colonization and straw maintenance, it achieves long-term improvement, sustainably enhances farmland fertility, and realizes ecological and long-term treatment of saline-alkali farmland. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the synergistic repair mechanism of the compound conditioning agent for saline-alkali land of the present invention; Figure 2This is a flowchart of the in-situ remediation cultivation method for saline-alkali land according to the present invention. Figure 3 This is a bar chart comparing the improvement effects of different repair systems of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. 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.

[0027] Example 1: In-situ remediation of mildly saline-alkali land like Figure 1 and Figure 2 As shown, this embodiment provides a composite conditioner suitable for mildly saline-alkali land, which is formulated in the following proportions by weight: 40 parts of calcium-based replacement modification component, 25 parts of organic chelated acid-regulating component, 22 parts of porous mineral salt-fixing component, 5 parts of salt-tolerant microbial repair component, and 3 parts of polyamino acid nutrient activating component.

[0028] The calcium-based replacement modification component consists of desulfurized gypsum and shell powder in a mass ratio of 2.5:1, with a particle size of 100 mesh and an effective calcium ion content of 23wt%, activated at 130℃ for 40 min; the organic chelate acidifying component consists of humic acid and fulvic acid in a mass ratio of 1.8:1, with an organic matter content of 62wt%; and the porous mineral salt-fixing component consists of zeolite and attapulgite in a mass ratio of 1.2:1, with a specific surface area of ​​190 m². 2 / g, porosity 46%; total effective viable bacteria count of the compound microbial agent 2.2×10 9 cfu / g.

[0029] Matching in-situ remediation tillage methods: Clear and level the plot, dredge the field irrigation and drainage system; evenly apply 50 kg of conditioner per acre; rotary till at 220 r / min to a depth of 22 cm, and deep loosen to a depth of 45 cm; saturate irrigate 35 m³ within 24 hours of application. 3 / mu, with two salt leaching irrigations at 8-day intervals, totaling 18m 3 / mu; natural drying for 4 days, combined with straw return to the field for stable maintenance.

[0030] Post-remediation test results: Soil pH stabilized at 8.0, soluble salt content in the topsoil decreased by 48%, soil aggregate structure ratio increased by 38%, and no salt or alkali return occurred within one year after remediation.

[0031] Example 2: In-situ remediation of moderately saline-alkali land like Figure 1 and Figure 2As shown, the conditioner in this embodiment is formulated by weight as follows: 45 parts calcium-based replacement modification component, 28 parts organic chelated acid-regulating component, 20 parts porous mineral salt-fixing component, 6 parts salt-tolerant microbial repair component, and 4 parts polyamino acid nutrient activating component.

[0032] Matching in-situ remediation tillage methods: Apply 80 kg of conditioner per acre; rotary till at 230 r / min to a depth of 25 cm, and deep loosen to a depth of 50 cm; initial saturated irrigation for 38 m³. 3 / mu, irrigate twice at 20m intervals every 9 days. 3 / acre; natural air drying for 5 days to complete steady-state maintenance.

[0033] Post-remediation test results: Soil pH stabilized at 7.8, soluble salt content decreased by 55%, soil aggregate structure ratio increased by 42%, soil physicochemical properties remained stable, and there was no trend of salinity rebound.

[0034] Example 3: In-situ remediation of severely saline-alkali land like Figure 1 and Figure 2 As shown, the conditioner in this embodiment is formulated by weight as follows: 52 parts calcium-based replacement modification component, 22 parts organic chelated acid-regulating component, 18 parts porous mineral salt-fixing component, 7 parts salt-tolerant microbial repair component, and 3 parts polyamino acid nutrient activating component.

[0035] Matching in-situ remediation tillage methods: Apply 110 kg of conditioner per acre; rotary till at 250 r / min to a depth of 25 cm, and deep loosen to a depth of 60 cm to break up the deep plow pan; initial saturated irrigation of 40 m³. 3 / mu, irrigate twice at 20m intervals every 10 days. 3 / acre; 5-day natural sun-drying for long-lasting maintenance.

[0036] Post-remediation test results: Soil pH stabilized at 8.1, soluble salt content decreased by 58%, soil aggregate structure ratio increased by 36%, deep soil permeability was significantly improved, and long-term stability was good.

[0037] Comparison of scale settings and performance tests To fully verify the synergistic innovative advantages of the modified formulation system, component modification process, stratified tillage and gradient leaching in-situ remediation process of this invention, multiple comparative groups were set up to conduct a 12-month standardized control experiment under the conditions of uniform saline-alkali soil matrix, uniform fertilizer application rate and uniform water and fertilizer management. All indicators were tested in accordance with national soil testing standards.

[0038] Basic experimental conditions: The experimental soil was typical saline-alkali farmland in North China, with an initial pH of 9.1 and a soluble salt content of 3.8 g / kg. The field management conditions were uniform, and the remediation and maintenance period was 12 months.

[0039] Comparative Example 1 (Conventional Single Calcium-Based Improvement and Remediation): Only ordinary desulfurized gypsum was used for improvement, without the addition of organic chelating components, porous mineral salt-fixing components, or salt-tolerant microbial components. Conventional shallow tillage and single leaching processes were adopted, and the remaining field management was consistent with Example 1.

[0040] Comparative Example 2 (unmodified conventional compound conditioner): The same raw material formulation and ratio as in Example 1 of this invention were used, but the calcium-based component was not subjected to low-temperature activation treatment, the porous mineral component was not subjected to high-temperature pore-forming modification, and conventional tillage and mixing process was used, while the other experimental conditions remained the same.

[0041] Comparative Example 3 (Conventional Single-Time Leaching Remediation Process): The modified composite conditioner of Example 1 of this invention was used, and only a single-time saturated irrigation leaching process was adopted. The multi-stage gradient leaching process of this invention was not adopted. All other application and tillage conditions were completely the same.

[0042] Comparative Example 4 (Shallow Single Tillage Process): The modified composite conditioner of Example 1 of this invention was used, and only shallow rotary tillage was performed. Deep loosening and breaking of the layer and construction of three-dimensional salt leaching channels were not implemented. The other application and leaching conditions were kept the same.

[0043] Comparison of test results Analysis of Experimental Conclusions like Figure 3 As shown in the results, multiple control experiments clearly demonstrate that this invention, through a composite modification process of low-temperature activated calcium-based components and high-temperature pore-forming mineral components, combined with a graded precision application, layered three-dimensional tillage, and multi-stage gradient leaching in-situ remediation system, produces a significant synergistic effect. Compared to traditional single-material improvement, unmodified compound systems, conventional single-stage leaching, and shallow tillage processes, the composite conditioner and supporting remediation process prepared in this invention significantly outperform existing technologies in terms of salinity reduction, soil improvement and stabilization, and long-term salt suppression. The experimental results fully demonstrate that the multi-component synergistic modification formula is the core of improving the comprehensive improvement capacity of saline-alkali land, and the layered three-dimensional tillage + gradient leaching process is the key design for achieving complete salt migration from the cultivated layer and long-term prevention of salt return. The combination of the two forms an excellent improvement effect that cannot be achieved by existing technologies, possessing unexpected technical effects, and demonstrating outstanding creativity and practicality.

[0044] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A compound conditioner for improving saline-alkali land, characterized in that, Based on parts by weight, it includes the following functional components: 35-55 parts of calcium-based replacement modified component 20-30 parts of organic chelated acid-regulating component 15-25 parts of porous mineral salt fixation component Salt-tolerant microbial remediation component 3-8 parts 2-5 parts of polyamino acid nutrient activating component; The calcium-based replacement modification component is a composite powder of desulfurized gypsum and shell powder with a mass ratio of 2 to 3:1, a particle size of 80 to 120 mesh, and an effective calcium ion content of not less than 22 wt%, used to replace adsorbed sodium ions in soil colloids. The organic chelated acid-regulating component is a compound system of humic acid and fulvic acid with a mass ratio of 1.5 to 2:1, and the total organic matter content is not less than 60 wt%. It is used to neutralize alkaline substances in the soil and chelate and passivate harmful ions in the soil. The porous mineral salt component is a composite powder of zeolite and attapulgite in a mass ratio of 1:1 to 1.5, with a specific surface area of ​​not less than 180 m². 2 / g, with a porosity of not less than 45%, used to adsorb free soil salts and inhibit salt accumulation on the surface; The salt-tolerant microbial remediation component is a compound bacterial agent consisting of Bacillus subtilis and Bacillus amyloliquefaciens in a 1:1 ratio of viable bacteria, with a total effective viable bacteria count of not less than 2.0 × 10⁻⁶. 9 cfu / g; The polyamino acid nutrient activating component is a mixture of polyaspartic acid and polyglutamic acid, used to relieve the solidification of soil trace elements under saline-alkali stress.

2. The compound conditioner for improving saline-alkali land according to claim 1, characterized in that, The calcium-based replacement modified component is activated at a low temperature of 120-150℃ for 30-45 minutes, which increases the calcium ion freeness by more than 30% compared with conventional powder; the porous mineral solid salt component is prepared by ultrafine grinding combined with high temperature pore-forming modification.

3. The compound conditioner for improving saline-alkali land according to claim 1, characterized in that, The organic chelated acid-regulating component can neutralize carbonate and bicarbonate ions in the soil, reduce the soil pH, and at the same time chelate and fix heavy metal ions in the soil.

4. The compound soil conditioner for saline-alkali land according to claim 1, characterized in that, The salt-tolerant microbial remediation component can colonize and reproduce in high-salt and high-alkali rhizosphere environments, reconstructing the soil microbial community structure and optimizing the crop rhizosphere microecological environment.

5. A method for in-situ remediation of saline-alkali land, comprising using the saline-alkali land composite soil conditioner as described in any one of claims 1 to 4 for in-situ soil remediation, characterized in that, Includes the following steps: S1. Site pretreatment: Remove surface stubble and weeds, level the site, dredge the field irrigation and drainage system, and form a continuous salt leaching drainage channel; S2. Graded and quantitative application: Apply the pesticide according to the degree of salinization. Apply 40-60 kg of conditioner per mu for mild salinization, 70-90 kg per mu for moderate salinization, and 100-120 kg per mu for severe salinization. Apply evenly to the surface of the plot. S3. Layered compound tillage: The tillage method is to combine shallow rotary tillage with deep loosening. Tillage is carried out at a rotary speed of 200-250 r / min for 20-25 cm to make the conditioner evenly mixed with the soil in the tillage layer, and the soil mixing uniformity is not less than 90%. Then, deep loosening is carried out for 30-60 cm to break up the plow pan in the field. S4. Gradual Irrigation in Stages: Within 24 hours of tillage completion, saturate irrigation is carried out using fresh water with a mineralization of ≤1g / L, with a single irrigation volume of 30-40m³. 3 / mu; repeat salt leaching irrigation every 7-10 days, with an irrigation volume of 15-20m³. 3 / mu; Irrigation adopts slow infiltration flood irrigation method, water flow velocity ≤0.5m / s; S5. In-situ stable maintenance: After salting, allow the soil to dry naturally for 3-5 days to avoid disturbing the deep soil. Combine this with straw return to the field to maintain the soil structure and achieve long-term salt control and alkali stabilization.

6. The in-situ remediation cultivation method for saline-alkali land according to claim 5, characterized in that, The remediation method employs in-situ soil improvement throughout the entire process, eliminating the need for soil replacement and the removal of saline-alkali soil.

7. The in-situ remediation cultivation method for saline-alkali land according to claim 5, characterized in that, The phased gradient leaching promotes the full sodium-calcium replacement reaction through the first saturated irrigation, and the second supplemental irrigation removes residual salts from the topsoil, thus completing the migration of salts from the topsoil.

8. The in-situ remediation cultivation method for saline-alkali land according to claim 5, characterized in that, The layered composite tillage model simultaneously completes the homogenization and soil improvement of the 0-25cm tillage layer and the loosening and salt-leaching of the 30-60cm deep soil, forming a vertical three-dimensional salt leaching channel.

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