Integrated method for rapid cultivation of arable land based on plough layer reconstruction and nutrient pool expansion

Abstract

The present application relates to the field of farmland quality improvement technology, and particularly relates to a farmland rapid cultivation integrated method based on plough layer reconstruction and nutrient reservoir capacity expansion, comprising the following steps: S100: constructing an inverted trapezoidal trench: cutting the plough layer of farmland to construct an inverted trapezoidal trench with a wide upper part and a narrow lower part; S200: injecting a precursor mixture: synchronously injecting a precursor mixture containing solid skeleton particles and liquid cementing agent into the trench while constructing the inverted trapezoidal trench; S300: in-situ solidification forming: causing the precursor mixture to have an in-situ solidification reaction in the inverted trapezoidal trench to generate a porous support column; S400: topsoil backfilling: backfilling topsoil to cover the porous support column, and the present application effectively solves the problems of quick soil backfilling and easy loss of filling materials in the existing deep loosening improvement technology through the coupling of underground inverted trapezoidal mechanical unloading space and in-situ chemical cross-linking forming technology.

Description

Technical Field

[0001] This invention relates to the field of arable land quality improvement technology, specifically to an integrated method for rapid arable land cultivation based on topsoil reconstruction and nutrient storage capacity expansion. Background Technology

[0002] With the increasing intensification of agriculture, long-term mechanical compaction and shallow tillage have resulted in the formation of a hard, closed "plow pan" at a depth of 20-40 centimeters in a large area of ​​arable land in my country. The existence of the plow pan cuts off the exchange of moisture and air between atmospheric precipitation and deep soil layers, hinders the deep root development of crops, and severely restricts their drought resistance and yield potential. Therefore, breaking up the plow pan and constructing a deep, active soil layer is a core task in building high-standard farmland.

[0003] Currently, the treatment of the plow pan mainly relies on mechanical deep tillage technology. This technology uses a deep tillage shovel to forcibly cut through the compacted layer, attempting to increase soil porosity. However, existing technologies suffer from a significant "recompaction" problem. Deep soils face enormous overburden pressure, and the V-shaped or rectangular trenches formed by conventional deep tillage, without internal support, are highly susceptible to lateral creep and collapse under their own weight. Coupled with rainfall leaching and subsequent dynamic load compaction from agricultural machinery operations, the pores formed by deep tillage typically close again within 6-12 months, and the soil bulk density returns to its pre-treatment level. This necessitates deep tillage operations to be carried out annually, resulting in enormous energy consumption and unsustainable effects.

[0004] To delay soil compaction and improve fertility, current techniques often involve filling deep tillage trenches with amendments such as biochar, straw, or organic fertilizer. However, these materials are usually filled directly in loose granular or powder form.

[0005] On the one hand, the loose materials lack bonding between them, making them prone to leaching and loss under the action of groundwater seepage, and difficult to remain in deep layers for a long time;

[0006] On the other hand, and most importantly, loose filler is a loose medium with almost no compressive strength. When the overlying soil settles, this filler is easily compressed and cannot provide effective radial support for the deep trench, thus failing to prevent the trench from closing.

[0007] In summary, existing technologies consistently lack a method for deep soil remodeling that organically combines "long-lasting mechanical support structures" with "highly efficient active amendment materials." How to construct underground channels that can resist soil compaction pressure while maintaining long-term water and fertilizer activity is a pressing technical challenge in the field of agricultural geotechnical engineering. Summary of the Invention

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides an integrated method for rapid cultivation of arable land based on topsoil reconstruction and nutrient storage capacity expansion, comprising the following steps: S100: Constructing an inverted trapezoidal trench: cutting the subsoil layer of the arable land to construct an inverted trapezoidal trench with a cross-section that is wider at the top and narrower at the bottom; S200: Injecting a precursor mixture: simultaneously injecting a precursor mixture containing solid skeleton particles and a liquid binder into the trench while constructing the inverted trapezoidal trench; S300: In-situ solidification and molding: causing the precursor mixture to undergo an in-situ solidification reaction within the inverted trapezoidal trench to generate a porous support column; S400: Topsoil backfilling: backfilling the porous support column with topsoil.

[0010] Further, in step S100, the construction of the inverted trapezoidal trench specifically includes: selecting a deep loosening shovel with lateral expansion blades as a cutting tool, setting the cutting depth to 20-50 cm below the plow layer; and constructing an inverted trapezoidal space with an upper bottom width of 8-15 cm, a lower bottom width of 3-8 cm, and a side wall inclination angle of 60°-80° through the squeezing action of the lateral expansion blades.

[0011] Furthermore, in step S100, during the cutting process, the inner wall of the groove is coated and compacted using the sidewall of the tool to form a dense hard shell layer with a thickness of 3-5 mm on the inner wall of the groove, so as to prevent the inverted trapezoidal groove from collapsing before the precursor mixture is injected; the center spacing of the inverted trapezoidal groove is set to 40-80 cm, and this spacing matches the row spacing of the crop to be planted, so that the inverted trapezoidal groove is located between or directly below the crop rows.

[0012] Further, in step S200, the precursor mixture is formed by mixing a solid framework component and a liquid binder component in a weight ratio of 1:1.5 to 1:4; the solid framework component is selected from at least one of biochar, activated carbon, bentonite, montmorillonite, and humic acid powder; the liquid binder component comprises a hydrophilic polymer solution with a mass fraction of 2% to 8% and a metal ion crosslinking agent solution with a mass fraction of 0.5% to 3%.

[0013] Furthermore, the hydrophilic polymer is - One or more of polyglutamic acid, polyaspartic acid, sodium alginate, or polyacrylamide; the metal ion crosslinking agent is calcium chloride, calcium lactate, or magnesium sulfate;

[0014] The in-situ curing reaction type of the precursor mixture is ion chelation crosslinking reaction; by adjusting the concentration of the crosslinking agent in the liquid cementing component, the initial setting time of the precursor mixture in the trench is controlled to be 10-40 minutes, so that it has fluidity before curing to fill the micropores at the bottom of the trench.

[0015] The liquid cementing component also contains rhizosphere growth promoters or biostimulants; the rhizosphere growth promoters contain dormant spores of Bacillus subtilis or gelatinous Bacillus, which are embedded in the gel network of the porous support column formed in situ.

[0016] Further, in step S300, the porous support column generated by the in-situ curing reaction is a viscoelastic semi-rigid gel; after curing, the semi-rigid gel forms a continuous three-dimensional network skeleton structure, which provides radial support force to the trench sidewalls, and the compressive strength of the porous support column is 50-300. saturated hydraulic conductivity greater than .

[0017] Furthermore, in step S400, the thickness of the topsoil backfill is 15-25 cm, so that the surface of the backfilled farmland is restored to the original elevation; the volume swelling rate of the porous support column in the water-saturated state is 10%-30%, and this swelling-shrinkage characteristic is used to construct a dynamic capillary connection at the interface between the porous support column and the backfill soil.

[0018] Furthermore, in step S400, the nutrient gradient enriched within the porous support column is used to induce crop roots to penetrate the backfill soil layer and oriented vertically into the inverted trapezoidal trench, forming a deep root network.

[0019] Beneficial effects

[0020] Compared with known public technologies, the technical solution provided by this invention has the following beneficial effects:

[0021] This invention effectively solves the problems of rapid soil compaction and easy loss of filling materials in existing deep tillage improvement technologies by coupling the construction of an underground inverted trapezoidal mechanical unloading space with in-situ chemical cross-linking molding technology. It utilizes the "soil arch effect" induced by the inverted trapezoidal trenches and the "semi-rigid gel skeleton" generated by in-situ self-assembly to form a dual mechanical support mechanism, constructing an active soil corridor in deep soil that can resist overlying loads for a long time (3-5 years) without closing. At the same time, by utilizing the unique dynamic swelling-shrinkage characteristics of the gel network, a stable water and fertilizer transmission and root induction channel is established underground, realizing the leap from "physical fragmentation" to "biomimetic reconstruction" of deep soil structure, significantly improving the water and fertilizer retention capacity of cultivated land and the depth of crop roots. Attached Figure Description

[0022] Figure 1 This is a flowchart of the integrated method for rapid cultivation of arable land based on topsoil reconstruction and nutrient storage capacity expansion, as described in this invention. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but includes other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings:

[0026] Example:

[0027] like Figure 1 As shown, the integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion includes the following steps:

[0028] S100: Constructing inverted trapezoidal trenches: Cutting the subsoil layer of cultivated land to construct inverted trapezoidal trenches with a cross-section that is wider at the top and narrower at the bottom;

[0029] Furthermore, the construction of the inverted trapezoidal trench specifically includes: using a deep loosening shovel with lateral expansion blades as the cutting tool, setting the cutting depth to 20-50 cm below the plow layer; through the squeezing action of the lateral expansion blades, constructing an inverted trapezoidal space with an upper base width of 8-15 cm, a lower base width of 3-8 cm, and a sidewall inclination angle of 60°-80°; during the cutting process, using the sidewall of the tool to coat and compact the inner wall of the trench, forming a dense hard shell layer with a thickness of 3-5 mm on the inner wall of the trench to prevent the inverted trapezoidal trench from collapsing before the precursor mixture is injected; the center spacing of the inverted trapezoidal trench is set to 40-80 cm, and this spacing matches the row spacing of the crop to be planted, so that the inverted trapezoidal trench is located between or directly below the crop rows.

[0030] In this embodiment, step S100 (constructing an inverted trapezoidal stress-relieving structure) is the foundation of the entire active soil corridor construction. Its core lies in utilizing a specially designed mechanical structure to construct a geometrically stable inverted trapezoidal space deep underground without damaging the surface vegetation cover. The specific implementation process is subdivided into the following sub-steps:

[0031] S101: Based on the soil texture (e.g., clay or loam) and the row spacing of the intended crops (e.g., 60cm for corn), set the work path. Select a vibratory subsoiler equipped with a "reverse wedge lateral spreader" as the work implement. Adjust the hydraulic suspension system of the subsoiler to set the penetration depth of the subsoiler shovel tip to 35cm below the plow pan (approximately 55cm below the surface, assuming a topsoil layer of 20cm). Simultaneously, adjust the pressure of the compaction wheel at the rear of the implement to ensure that surface cracks are sealed promptly while the soil is being cut, preventing excessive moisture evaporation.

[0032] S102: Start the tractor unit, and the subsoiler tip, under hydraulic pressure, vertically penetrates the soil. Once the tip breaks through the hard plow pan (usually located 20-30cm underground), the shank follows, cutting an initial guide slit approximately 2-3cm wide vertically. This process utilizes the high-speed impact force of the tip to break up the hardened plow pan, eliminating vertical physical barriers and providing stress release space for subsequent lateral expansion.

[0033] S103: As the subsoil shovel moves forward, the "reverse wedge-shaped side spreader" installed in the lower part of the shovel handle enters the subsoil layer. The spreader's cross-section is designed as an inverted trapezoidal structure, wider at the top and narrower at the bottom. Its upper wingspan is set at 12cm, its lower wingspan at 5cm, and its sidewall inclination angle is designed at 70°. As the machine moves forward, the spreader forcibly pushes the soil particles on both sides outward, causing plastic displacement. Unlike traditional soil turning operations, this process does not overturn the soil layer. Instead, it utilizes the rheological properties of the soil under deep, high confining pressure to horizontally compress the originally compacted soil to both sides, thereby "supporting" an inverted trapezoidal cavity with the same shape as the spreader in situ behind the shovel body.

[0034] The cross-sectional area of ​​the constructed inverted trapezoidal trench It can be determined by the following formula:

[0035]

[0036] in, The width of the top base is 8-15 cm. The width of the bottom base is 3-8 cm. This is the vertical cutting depth. The sidewall inclination angle is controlled. This ensures the effective formation conditions of the soil arch effect:

[0037]

[0038] S104: To prevent the newly formed inverted trapezoidal cavity from collapsing before the filling material is injected, this embodiment utilizes the "smearing effect" generated at the mechanical-soil contact surface. The sidewall surface of the expander is polished and hardened. During the high-pressure friction with the soil, the clay particles at the contact surface are rearranged and compacted, thereby forming a high-density hard shell layer with a thickness of approximately 3-5 mm on the inner wall of the inverted trapezoidal trench. This hard shell layer acts like a "temporary lining" for the tunnel, significantly improving the shear strength of the trench inner wall and enabling it to withstand the creep pressure of the overlying soil layer for approximately 5-10 minutes. This valuable "stabilization window" provides the necessary time guarantee for the synchronous injection and filling of the precursor mixture in the subsequent step S200, ensuring that the trench does not collapse or the surface does not float before the filling material is injected.

[0039] S105: As the machinery passes, the soil above the trench attempts to sink under its own weight. However, due to the trench's inverted trapezoidal geometry (wider at the top and narrower at the bottom) and the compacted soil walls on both sides, the force chains within the overlying soil particles redistribute after sinking a small distance. The stress path deflects, shifting from vertically downwards to being transmitted to the solid soil columns on both sides. At this point, a "natural soil arch" is initially formed in the area above the inverted trapezoidal trench. This soil arch structure "suspends" most of the overlying load, keeping the trench interior in a low-stress state and creating an ideal mechanical environment for the molding and long-term preservation of the soft gel material.

[0040] S200: Injection of precursor mixture: While constructing the inverted trapezoidal trench, a precursor mixture containing solid skeleton particles and liquid binder is simultaneously injected into the trench;

[0041] Furthermore, the precursor mixture is composed of a solid framework component and a liquid binder component mixed in a weight ratio of 1:1.5 to 1:4; the solid framework component is selected from at least one of biochar, activated carbon, bentonite, montmorillonite, and humic acid powder; the liquid binder component comprises a hydrophilic polymer solution with a mass fraction of 2%–8% and a metal ion crosslinking agent solution with a mass fraction of 0.5%–3%; the hydrophilic polymer is... - One or more of polyglutamic acid, polyaspartic acid, sodium alginate, or polyacrylamide; the metal ion crosslinking agent is calcium chloride, calcium lactate, or magnesium sulfate; the in-situ curing reaction type of the precursor mixture is ion chelation crosslinking reaction; by adjusting the concentration of the crosslinking agent in the liquid cementing component, the initial setting time of the precursor mixture in the trench is controlled to be 10-40 minutes, so that it has fluidity before curing to fill the micropores at the bottom of the trench; the liquid cementing component also contains rhizosphere growth promoters or biostimulants; the rhizosphere growth promoters contain dormant spores of Bacillus subtilis or gelatinous Bacillus, and the dormant spores are embedded in the gel network of the porous support column generated by in-situ curing.

[0042] Following the construction of the inverted trapezoidal trench in step S100, within a "window period" of just a few seconds after the expanding blades of the subsoiler have passed over the trench and before the trench sidewalls have creeped back, step S200 (injection of the two-component self-assembled matrix) is immediately executed. This step achieves synchronous injection and micro-mixing of the matrix through a precisely controlled fluid delivery system. The specific implementation process is subdivided into the following sub-steps:

[0043] S201: Adopts a "solid-liquid separation, terminal mixing" strategy. Two independent storage tanks are set on the traction platform of the work vehicle.

[0044] Tank A (solid skeleton suspension): Stores a mixture consisting of modified biochar particles (0.5-1.5 mm in diameter), sodium bentonite powder, and humic acid powder. To facilitate pumping, an appropriate amount of carrier liquid (water) is added to Tank A before operation, and the mixture is continuously stirred with the agitator inside the tank to prepare a "high solids content slurry" with shear-thinning properties.

[0045] Tank B (liquid cementitious initiator): Storage concentration 4% An aqueous solution, pre-dissolved with 1.5% anhydrous calcium chloride. As a cross-linking agent, the solution is transparent and viscous, and can be made into a biologically active fluid by adding rhizosphere growth-promoting bacteria (such as dormant spores of Bacillus subtilis).

[0046] S202: Start the dual-head screw pump system installed at the rear of the locomotive. This pump has positive displacement conveying characteristics and can precisely control the flow rate. Component A slurry and component B solution are conveyed through two independent high-pressure resistant conveying pipes, extending downwards along the back of the subsoil shovel handle. At this time, the pressure of the screw pump overcomes frictional resistance, rapidly conveying the two materials to the "injection port assembly" located at a depth of 35-40cm underground. The conveying pressure is set to... The pressure is slightly higher than the pore water pressure in the deeper soil layers to ensure that the material can be sprayed out smoothly.

[0047] S203: Two feed pipes converge at the tail of the expanding vane of the deep loosening shovel, entering a specially designed "static mixing chamber." Within this chamber, the high-velocity B-component jet collides violently with the A-component slurry in a small space. Utilizing the turbulence effect in fluid dynamics, the... The polymer chains rapidly coat the surfaces of the biochar and bentonite particles within milliseconds. At this point, calcium ions within the system begin to interact with... The carboxyl groups on the molecular chain coordinate and bind. By adjusting the formula, the induction period (i.e., the time from mixing to loss of fluidity) is precisely controlled to about 15 minutes. This means that the mixture maintains good liquid fluidity when it is sprayed out of the nozzle, allowing it to penetrate into every corner of the trench.

[0048] S204: The mixed precursor mixture is ejected in a fan shape from the nozzle below the expander vane. The injection process follows the "follow-up filling" principle, meaning the nozzle's movement speed is completely synchronized with the machine's forward speed. The fluid mixture first fills the bottom (lower area) of the inverted trapezoidal trench, utilizing the fluid's self-leveling properties to quickly fill the tiny gaps at the bottom of the trench, and relying on its own hydrostatic pressure to support the lower sidewalls of the trench. As the injection volume continues to increase, the liquid level of the mixture gradually rises from bottom to top until it fills the entire inverted trapezoidal space (approximately 10-15 cm in height). During this process, the liquid slurry generates a certain lateral support force on the inner wall of the trench, not only offsetting part of the sidewall soil pressure, but also penetrating into the trench wall by about 1-2 mm through permeation, fusing with the "hard shell layer" formed in step S104, laying the foundation for subsequent solidification and rooting.

[0049] S300: In-situ curing molding: The precursor mixture undergoes an in-situ curing reaction within the inverted trapezoidal groove to generate a porous support column;

[0050] Furthermore, in step S300, the porous support column generated by the in-situ curing reaction is a viscoelastic semi-rigid gel; after curing, the semi-rigid gel forms a continuous three-dimensional network skeleton structure, which provides radial support force to the trench sidewalls, and the compressive strength of the porous support column is 50-300. saturated hydraulic conductivity greater than .

[0051] After the precursor mixture in step S200 fills the inverted trapezoidal trench, the interior of the trench enters a static reaction stage as the injection equipment leaves. Step S300 (induced in-situ crosslinking molding) utilizes the natural underground temperature (typically 10-25℃) as an environmental condition, relying on chemical kinetics to spontaneously complete the phase transition process from "liquid sol" to "semi-rigid gel". The specific implementation process is subdivided into the following sub-steps:

[0052] S301: The first 5-10 minutes after the precursor mixture is injected into the trench are the "viscosity mutation period". Within the mixture system, The long-chain molecules of polyglutamic acid fully extend in the aqueous environment. At this time, the divalent calcium ions released from component B begin to act as "molecular bridges." Calcium ions, through electrostatic attraction, quickly find the negatively charged carboxyl sites (-COO⁻) on the PGA molecular chains. Unlike ordinary chemical polymerization, this embodiment involves physical cross-linking. Calcium ions, through coordination bonds, "hook" two or more adjacent PGA molecular chains together, forming a chelate structure similar to an "egg carton model." Macroscopically, this manifests as an exponential increase in fluid viscosity within the trench, with a rapid loss of fluidity, thus preventing excessive seepage of the slurry into deeper soil layers.

[0053] calcium ions and Carboxyl groups on the molecular chain The coordination crosslinking reaction that occurs can be represented by the following formula:

[0054]

[0055] The "egg-box" structure formed by this reaction is what causes the system's viscosity. Over time The main reasons for the exponential growth:

[0056]

[0057] in The initial viscosity, This is the reaction rate constant related to the crosslinking agent concentration.

[0058] S302: Within 10-30 minutes after injection, the system undergoes a sol-gel phase transition. As the crosslinking density increases, the PGA molecular chains weave together a continuous, three-dimensional supramolecular hydrogel network. This network acts like a three-dimensional fishing net, tightly wrapping, entangled, and fixing the solid particles (modified biochar, bentonite, and humic acid) introduced in step S200 to the grid nodes. This process achieves "microstructural restructuring": the originally loose carbon powder and soil particles are "cemented" into a whole by the polymer network. The biochar particles are no longer free impurities but become "rigid aggregates" that enhance the gel strength (similar to stones in concrete), while the gel network acts as "cement."

[0059] S303: Before S301 completely loses its fluidity, the liquid precursor mixture, under hydrostatic pressure, penetrates into the micropores of the inverted trapezoidal trench sidewalls (i.e., the hard shell layer crevices formed in step S104). When the gelation reaction occurs in S302, the slurry that has penetrated into the sidewall pores solidifies simultaneously, forming countless micron-sized "gel roots." These gel roots, like micro-rivets, tightly "rivet" the in-situ generated gel pillars to the solid soil on both sides. This "interfacial interpenetrating network" eliminates the sliding surface between the gel and the soil, allowing the gel pillars to deform in tandem with the surrounding soil, rather than being displaced by the soil as a foreign object.

[0060] S304: The curing reaction is basically complete 30-60 minutes after injection, and the gel column reaches its "final stable state." At this time, a unique multi-level porous structure is formed inside the gel column:

[0061] Primary pores (skeletal pores): micropores inherent in biochar itself. It is used to adsorb molecular-level nutrients.

[0062] Secondary pores (structural pores): macropores created by the dehydration and shrinkage of the gel network. It is used to store water and provide space for root penetration. Meanwhile, the compressive strength of the gel column gradually increases to... Within the design scope. At this point, the column exhibits semi-rigid characteristics: it has sufficient rigidity to support the lateral pressure of the inverted trapezoidal soil walls on both sides, preventing the soil arch foot from becoming unstable; it also has a viscoelasticity similar to rubber, so that when agricultural machinery passes over it, it can produce elastic deformation to absorb energy, rather than undergoing brittle fracture like a rigid pipe.

[0063] The permeability of gel columns follows Darcy's law, and their saturated hydroconductivity is... Defined as:

[0064]

[0065] in For steady-state seepage flow, This is the seepage path length. The cross-sectional area of ​​the water passage is... This is due to the difference in hydraulic head. The hydraulic conductivity is significantly higher than that of the surrounding compacted soil, ensuring the formation of preferential flow channels.

[0066] S400: Topsoil backfill: Backfill the topsoil to cover the porous support column.

[0067] Furthermore, in step S400, the thickness of the topsoil backfill is 15-25 cm, so that the surface of the cultivated land after backfilling is restored to the original elevation; the volume swelling rate of the porous support column in the water-saturated state is 10%-30%, and this swelling-shrinkage characteristic is used to construct a dynamic capillary connection at the interface between the porous support column and the backfill soil; the nutrient gradient enriched in the porous support column is used to induce crop roots to penetrate the backfill soil layer and directionally and vertically penetrate into the inverted trapezoidal trench, forming a deep root network.

[0068] Once the in-situ solidification reaction in step S300 is essentially complete, forming a gel column with initial strength, step S400 (topsoil backfilling and functional activation) can proceed. This step restores the structure of the topsoil layer, establishing hydraulic and mechanical continuity between the underground artificial structure and the natural soil environment, thus formally forming the "active soil corridor." The specific implementation process is further divided into the following sub-steps:

[0069] S401: Backfilling is performed using the "soil covering and compaction assembly" mounted at the rear of the work unit. First, the topsoil (cultivated soil) cut and turned over during deep tillage is backfilled above the inverted trapezoidal trench. The backfill thickness is controlled to approximately 15-25cm, just filling the space from the top of the gel column (20-25cm below ground) to the surface. Then, a contour compaction roller is used to lightly compact the backfilled surface. The compaction force is controlled at 30-50. The purpose is to eliminate large voids in the loose soil, restore the flatness of the ground surface, and avoid excessive impact damage to the gel column below.

[0070] S402: After backfilling is completed, the self-weight pressure of the overlying soil layer begins to act on the underlying structure. At this time, the core "structural coordination mechanism" of this invention is activated:

[0071] For the soil: The main part of the overburden pressure is effectively transferred and guided to the undisturbed solid soil columns on both sides of the trench through the inverted trapezoidal slope constructed in step S100, marking the final closure and stabilization of the "stress arch".

[0072] For the gel column: the remaining small portion of the vertical pressure acts on the top surface of the gel column. Since the gel column generated in step S300 has semi-rigid support, it can withstand this part of the load and prevent the surface from collapsing. Thus, a stable "arch-column" mechanical equilibrium system is formed, and the underground passage will not close even if heavy agricultural machinery (such as harvesters) rolls over it in subsequent operations.

[0073] S403: The hydraulic function of the active soil corridor is activated during the first rainfall or irrigation after backfilling. (Deeply buried underground) Upon contact with infiltrated water, the gel column rapidly absorbs water due to its high hydrophilicity, resulting in volume swelling. According to the formulation design, its volume swelling rate is set at 10%-30%. This moderate expansion generates a "microscopic compressive pressure," forcing the gel surface to adhere tightly to the surrounding backfill soil and trench sidewalls, eliminating interfacial cracks caused by soil shrinkage and establishing capillary continuity.

[0074] During the wet period: the gel absorbs water and swells, becoming an "underground reservoir" that intercepts and stores leaked nutrients;

[0075] During dry periods: The gel slowly releases water and shrinks slightly, creating air gaps at the contact interface. This cyclical swelling-shrinking process simulates the "dynamic breathing" of the soil, preventing the channels from becoming blocked.

[0076] When a gel column absorbs water and swells, the swelling ratio is... The calculation formula is as follows:

[0077]

[0078] In the formula, This represents the volume of the gel column after it has become saturated with water. To define the initial volume after in-situ curing, set exist Between these, suitable expansion pressure can be generated. To maintain interfacial contact without damaging the soil structure.

[0079] S404:

[0080] Biological induction and deep root development: After a 1-2 week soil adaptation period, the active soil corridor enters the "biological function period".

[0081] Microbial resuscitation: Growth-promoting bacteria (such as Bacillus subtilis) spores embedded in the gel network awaken and multiply in large quantities under suitable temperature, humidity and carbon source (humic acid) protection, and begin to secrete plant growth hormones (IAA).

[0082] Root-targeted induction: When crop roots grow to the plow pan interface, high concentrations of water and fertilizer signals and biostimulant signals released from the gel columns below are detected. Driven by chemotropism and hydrotropism, the roots penetrate the hard plow pan and directionally enter the inverted trapezoidal gel columns with less resistance. Ultimately, guided by the gel columns, the crop roots break through the original 20cm shallow growth layer and penetrate 40-50cm underground, constructing a vast deep root network and achieving a fundamental improvement in farmland productivity.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion, characterized in that, Includes the following steps: S100: Constructing inverted trapezoidal trenches: Cutting the subsoil layer of cultivated land to construct inverted trapezoidal trenches with a cross-section that is wider at the top and narrower at the bottom; S200: Injection of precursor mixture: While constructing the inverted trapezoidal trench, a precursor mixture containing solid skeleton particles and liquid binder is simultaneously injected into the trench; S300: In-situ curing molding: The precursor mixture undergoes an in-situ curing reaction within the inverted trapezoidal groove to generate a porous support column; S400: Topsoil backfill: Backfill the topsoil to cover the porous support column.

2. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 1, characterized in that, In step S100, the construction of the inverted trapezoidal trench specifically includes: selecting a deep loosening shovel with lateral expansion blades as a cutting tool, setting the cutting depth to 20-50 cm below the plow layer; and constructing an inverted trapezoidal space with an upper bottom width of 8-15 cm, a lower bottom width of 3-8 cm, and a side wall inclination angle of 60°-80° through the squeezing action of the lateral expansion blades.

3. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 2, characterized in that, In step S100, during the cutting process, the inner wall of the groove is coated and compacted using the sidewall of the tool to form a dense hard shell layer with a thickness of 3-5 mm on the inner wall of the groove, so as to prevent the inverted trapezoidal groove from collapsing before the precursor mixture is injected.

4. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 3, characterized in that, The center-to-center spacing of the inverted trapezoidal trenches is set to 40-80 cm, and this spacing matches the row spacing of the crops to be planted, so that the inverted trapezoidal trenches are located between or directly below the crop rows.

5. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 4, characterized in that, In step S200, the precursor mixture is formed by mixing a solid framework component and a liquid binder component in a weight ratio of 1:1.5 to 1:4; the solid framework component is selected from at least one of biochar, activated carbon, bentonite, montmorillonite, and humic acid powder.

6. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 5, characterized in that, The liquid cementing component comprises a hydrophilic polymer solution with a mass fraction of 2%–8% and a metal ion crosslinking agent solution with a mass fraction of 0.5%–3%; the hydrophilic polymer is… One or more of polyglutamic acid, polyaspartic acid, sodium alginate, or polyacrylamide; the metal ion crosslinking agent is calcium chloride, calcium lactate, or magnesium sulfate.

7. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 6, characterized in that, The in-situ curing reaction of the precursor mixture is an ion chelation crosslinking reaction; by adjusting the concentration of the crosslinking agent in the liquid binder component, the initial setting time of the precursor mixture in the trench is controlled to be 10-40 minutes, so that it has fluidity before curing to fill the micropores at the bottom of the trench.

8. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 7, characterized in that, The precursor mixture also contains rhizosphere growth promoters or biostimulants; the rhizosphere growth promoters contain dormant spores of Bacillus subtilis or Bacillus lentigines, which are embedded in the gel network of the porous support column formed in situ.

9. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 8, characterized in that, In step S300, the porous support column generated by the in-situ curing reaction is a viscoelastic semi-rigid gel; after curing, the semi-rigid gel forms a continuous three-dimensional network skeleton structure, which provides radial support force to the trench sidewalls, and the compressive strength of the porous support column is 50-300 kPa, and its saturated water conductivity is greater than... .

10. The integrated method for rapid farmland cultivation based on topsoil reconstruction and nutrient storage capacity expansion according to claim 9, characterized in that, In step S400, the thickness of the topsoil backfill is 15-25 cm; the volume swelling rate of the porous support column under water saturation is 10%-30%. This swelling-shrinkage characteristic is used to construct a dynamic capillary connection at the interface between the porous support column and the backfill soil, and the nutrient gradient enriched in the porous support column is used to induce the crop roots to penetrate vertically in a directional manner.

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