A kind of soda saline dry field corn direct seeding rhizosphere improvement particle and application method

Abstract

The application discloses a kind of soda saline dry field corn direct seeding rhizosphere improvement particle and application method, belong to saline soil improvement and dry field crop sowing ditch rhizosphere environment regulation technical field.The technical problem to be solved is that existing modifier is insufficient in particle size, release time, application depth and application distance limitation, unable to carry out hierarchical positioning for seed near area and taproot lower penetration area, there are problems such as large dosage, non-matching of effect window and corn emergence stage, insufficient calcium supply in later period, inaccurate sowing ditch rhizosphere micro-area regulation and the like.The technical solution points are that fast-release component F and slow-release component S are granulated respectively, F / S particle size difference, window difference, sowing ditch space positioning, corn emergence period rhizosphere calcium and sodium replacement regulation are utilized, and rhizosphere micro-area regulation and control technology that material composition, particle size, release time and corn sowing ditch space position are matched is established.

Description

Technical Field

[0001] This invention belongs to the field of saline-alkali soil improvement and rhizosphere environment regulation in sowing furrows for dryland crops, specifically involving a soda-based rhizosphere improvement granule for direct-seeded corn in saline-alkali dryland fields and its application method. Background Technology

[0002] Saline-alkali land is an important reserve of arable land in my country. Among them, soda saline-alkali land, due to its high sodium carbonate and sodium bicarbonate content, high soil pH, high alkalinity, poor structure, and weak infiltration capacity, makes it difficult for crops to emerge and grow, making it one of the most difficult types of saline-alkali land to improve. Corn is one of the main crops in saline-alkali dryland. Under the direct seeding method, seed germination, radicle breakthrough, taproot development, and seedling emergence are all concentrated in a small area of ​​the sowing furrow. Under the combined effects of high alkalinity stress, surface crusting, and insufficient calcium supply, problems such as low emergence rate, poor uniformity, and stunted seedling growth often occur.

[0003] Existing saline-alkali land conditioners are mostly designed from the perspective of material composition, such as calcium-based materials like phosphogypsum and desulfurized gypsum, acidic materials like organic acids and humic acids, and mixtures of conditioners like biochar and organic fertilizers. While these solutions can lower soil pH or replenish calcium ions to some extent, they still have three key drawbacks in the context of direct-seeded corn: First, the application methods are mainly broadcasting and mixed application in the same layer, which cannot concentrate the effective components in the seed area and the key area where the main root grows, resulting in low material utilization, large dosage and high cost. Second, if fast-release acidic materials come into direct contact with seeds, they can easily cause fluctuations in local ionic strength and acidity, creating a risk of burning the seeds and affecting their water absorption and germination. Third, calcium sources such as gypsum dissolve slowly under low moisture conditions in dry fields, and the release of calcium ions lags behind the critical period of corn taproot development (3-15 days after sowing), making it impossible to complete the Ca²⁺ ion release in a timely manner. + -Na + Replacement and improvement methods have limited effectiveness.

[0004] Relevant patent documents retrieved: This patent, published in China (CN121652813A) on March 13, 2026, discloses a soil conditioner based on citric acid gypsum, its preparation method, and its application. The process involves mixing 80-90 parts by weight of component A, 1-2 parts by weight of component B, and 5-10 parts by weight of component D, while spraying 2-3 parts by weight of component C during the mixing process. After thorough mixing, the mixture is passed through a 2mm sieve. Component A is gypsum, a byproduct of corn fermentation for citric acid production (dry basis); component B is selected from at least one of activated carbon, rice husk biochar, and humic acid; component C is selected from at least one of citric acid aqueous solution, malic acid aqueous solution, and lactic acid aqueous solution; and component D is organic fertilizer. This soil conditioner is environmentally friendly and can lower soil pH, increase soil aggregate content, porosity, and water and air permeability.

[0005] The document, published in China (CN121319940A) on January 13, 2026, discloses a slow-release saline-alkali soil conditioner based on phosphogypsum and its preparation method. The conditioner has a core-shell structure, comprising a core and an outer shell. The core includes phosphogypsum, organic matter, humic acid, microorganisms, N, P, K, and calcium sulfate and complexed Ca generated by the reaction of humic acid, amino acids, and phosphogypsum. The outer shell is a biodegradable microporous slow-release membrane.

[0006] The prior art represented by the aforementioned documents has at least the following unresolved technical problems or defects: 1. CN121652813A soil conditioner requires a large dosage, but its improvement effect is generally limited. The relevant evidence is as follows: when applying soil conditioner at a rate of 45-60 tons / hectare using a fertilizer spreader, the soil pH value before improvement was 9.36-10.32, 9.31-10.15, and 9.47-10.43, respectively, and after improvement, the soil pH value decreased to 8.48-9.31, 8.48-9.31, and 8.61-9.39, respectively.

[0007] 2. CN121319940A has a complex preparation process, makes it difficult to maintain the activity of microbial agents, and the degradation rate is uncontrollable. Relevant evidence includes steps such as water washing, neutralization, and ultrasonic or microwave treatment. Furthermore, the coating process has high requirements, and the performance of the microbial agents may be affected by granulation, coating, drying, and other processes.

[0008] Furthermore, there has long been a technological inertia in this field that "saline-alkali land improvement requires uniform application across the entire layer, and the larger the dosage, the more stable the improvement effect." Research and development approaches have generally focused on improving the acid-base neutralization capacity or calcium content of the materials themselves, without considering the spatially stratified and temporally phased characteristics of stress during the corn direct seeding stage. Existing technologies either solely pursue rapid alkali reduction or solely pursue long-term calcium supply, always treating these two as parallel needs within the same space. They have failed to realize that spatially partitioned deployment within the planting furrow, with "rapid-release alkali reduction in the upper layer and slow-release calcium supply in the lower layer," can promote calcium source dissolution through infiltration in an acidic environment, achieving a closed-loop synergy of "alkali reduction-displacement-leaching," with effects far exceeding the simple superposition of materials. This invention is a solution proposed based on this undiscovered technological principle.

[0009] In solving the above problems or overcoming the above defects, the present invention encountered the following difficulties and obstacles: First, while direct and extensive contact of fast-release materials with seeds can temporarily lower the local pH, it can also cause fluctuations in local ionic strength and acidity, affecting the water absorption and germination of corn seeds. Second, under low-moisture conditions in dryland planting furrows, gypsum... + The release is slow, making it difficult to cover the critical window of radicle breakthrough and taproot development 3-15 days after sowing; third, conventional whole-field application requires a high dosage, and the effective components are difficult to concentrate in the seed vicinity and taproot expansion zone; fourth, simply mixing weak acid, iron salt, calcium source, and charcoal material into particles of the same size makes it difficult to simultaneously meet the opposing release requirements of "rapid alkali reduction in the upper part" and "continuous calcium supply in the lower part." To resolve the above contradictions, this invention granulates F and S separately and defines them by coupling through particle size, release window, and sowing furrow location.

[0010] Other content that is useful for understanding, searching, and examining this invention: Existing calcium-based amendments are mostly applied by broadcasting or mixing in the same layer across the field, failing to concentrate their effect on the area near the corn seeds and the zone where the taproot grows. If fast-release acidic materials are placed too close to the seeds, they can easily cause localized fluctuations in acidity or salinity, affecting water absorption and germination. Calcium sources such as gypsum, when applied to low-moisture sowing furrows in dry fields, can contribute to calcium absorption. + Slow release, unable to cover the primary root growth and Ca²⁺ 3–15 days after sowing. + -Na + The critical period for replacement. Existing technologies do not limit material release time, particle size, application depth, application distance, and maize root development stage as a unified technical combination.

[0011] This invention does not simply combine conventional materials such as gypsum, weak acid, and biochar. Instead, it granulates the fast-release component F and the slow-release component S separately, and uses particle size differences, release window differences, and spatial positioning in the sowing furrow to define the technical solution. This allows component F to rapidly reduce alkalinity in the seed vicinity for 12-36 hours, while component S provides continuous Ca² supply to the root zone for 5-15 days.+ This results in a process of "rapid alkali reduction in the seed vicinity—continuous calcium supply in the main root zone—Ca²⁺". + -Na + Replacement —Na + The spatiotemporal partitioning control path of "downward shift". Summary of the Invention

[0012] The purpose of this invention is to provide: The purpose of this invention is to provide a rhizosphere amendment granule and its application method for direct-seeded maize in soda-saline-alkali dryland fields. The technical problem this invention aims to solve is: addressing the high pH / HCO3 ratio in the early seed zone during direct-seeded maize in moderately to severely soda-saline-alkali dryland fields. - / CO3² - Stress, surface crusting, and Ca² in the area where the main root grows. + Insufficient supply, Na + This invention addresses a complex obstacle, including displacement lag, by providing a method that enables rapid alkalinity reduction in the seed vicinity within the sowing furrow, continuous calcium supply to the taproot growing area, and Ca²⁺. + -Na + Phased replacement and Na + Rhizosphere amendment particles that migrate downstream with water and their targeted application methods.

[0013] The mechanism of action of this invention can be summarized as "rapid release of F in the upper part to reduce alkali, slow release of S in the lower part to supply calcium, micro-stratification and replacement of rhizosphere, and Na..." + "It migrates downstream with the water." Component F is located beside or above the seed, has a smaller particle size, and releases acid-neutralizing ability within 12-36 hours after sowing, reducing the pH and HCO3 in the seed vicinity. - / CO3² - The dominant alkaline stress provides a low-alkalinity microzone for water absorption and germination, radicle breakthrough and emergence.

[0014] The S component is located below or to the side of the seed, has a larger particle size, and continuously releases Ca²⁺ 5-15 days after sowing. + It acts on the area where the main root grows, promoting the adsorption of Na by soil colloids. + Ca² + Replacement, and in conjunction with precipitation or irrigation, to reduce Na + Migrate downwards. Thus, component F addresses early-stage alkali stress, while component S addresses later-stage Ca² supply. + and Na + The substitutions, in turn, connect the two in time and divide them in space.

[0015] Terminology Explanation: Unless otherwise defined, all technical terms in this document have the same meanings as commonly understood by one of ordinary skill in the art to which the subject matter of the claims pertains. Unless otherwise stated, all patents, patent inventions, and publications cited in this document are incorporated herein by reference in their entirety. If multiple definitions exist for terms in this document, the definitions in this chapter shall prevail.

[0016] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0017] The terms and measurement methods for commonly used terms in this field, such as saline-alkali soil, exchangeable sodium, CEC, pH, and EC, can be found in the references *Chinese Saline Soil* (Science Press, Wang Zunqin et al., 1993), *Methods for Soil Agricultural Chemical Analysis* (China Agricultural Science and Technology Press, Lu Rukun, ed., 2000), and *Soil Science* (China Agricultural Press, Huang Changyong and Xu Jianming, 3rd edition). These references are only used to explain common terms and routine detection methods in this field and are not intended to limit the scope of protection of this invention.

[0018] Unless otherwise stated, soil pH, EC, exchangeable Na+ + Exchangeability Ca² + CEC, ESP, soluble Ca² + / Na + Indicators such as surface crust strength and seedling emergence rate were all determined using conventional methods in the fields of soil science and agricultural chemical analysis.

[0019] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0020] The terms “optional / arbitrary” or “optionally / arbitrarily” mean that the event or situation described below may or may not occur, including both the occurrence and non-occurrence of the event or situation.

[0021] The term "planting furrow application" as used in this article refers to the application method in which materials such as amendments or fertilizers are precisely applied into the planting furrow near the seeds or at a specific depth below the seeds during corn planting, so as to achieve spatial matching between the materials and the seed root system and improve utilization efficiency.

[0022] The term "exchangeable sodium percentage" used in this article refers to ESP (Exchangeable Sodium Percentage), which is the percentage of exchangeable sodium ions adsorbed on soil colloids relative to the cation exchange capacity (CEC). It is a core indicator for measuring the degree of soil alkalization and the level of soda salinity hazards.

[0023] The term “moderate to severe soda saline-alkali dryland” used in this article refers to saline-alkali arable land with a soil pH value usually above 9.0, an exchangeable sodium percentage (ESP) above 20%, and a salt content mainly consisting of sodium carbonate and sodium bicarbonate. Due to the deterioration of its physical structure and extremely poor permeability, it is unsuitable or difficult to carry out paddy field cultivation and is mainly used for dryland agriculture.

[0024] The term "direct seeding of maize" as used in this article refers to a planting method in which maize seeds are sown directly into the field soil at the designed plant and row spacing after the previous crop is harvested, without going through the seedling raising and transplanting process, and rely on the natural conditions of the field to complete germination and emergence.

[0025] The term "material release window" as used in this article refers to the time interval during which the active ingredients of a functional material (such as a soil conditioner, coated fertilizer, or microbial carrier) applied to the soil begin to be released significantly and maintain their effective effect under specific environmental conditions (humidity, temperature, microbial activity, etc.).

[0026] The term "rhizosphere microzone regulation technology" used in this article refers to a technical system that uses physical, chemical, or biological means to directionally regulate the microenvironment (such as pH, salinity, ionic composition, beneficial microbial populations, etc.) within a range of millimeters to centimeters around the rhizosphere of seeds or seedlings in order to create a local "microenvironment" suitable for root growth.

[0027] The term "surface crust strength" used in this article refers to the compressive or penetrability resistance of the dense, hard crust (crust layer) formed on the soil surface due to raindrop impact, irrigation, or alternating wet and dry conditions. It is usually expressed as penetration resistance or shear strength, and its strength directly affects seedling emergence and gas exchange.

[0028] The term "Ca²" used in this article + -Na + "Displacement" refers to an ion exchange reaction that occurs at the solid-liquid interface of soil, where an external calcium source (such as gypsum, calcium chloride, etc.) provides Ca²⁺. + Exchangeable Na adsorbed by soil colloids + Displaced, thus causing Na + It enters the solution phase, providing the chemical basis for subsequent elution and desalination.

[0029] The term "Na" used in this article +"Migration leaching" refers to the leaching of Na+ from the soil solution under irrigation or precipitation conditions. + The process of water moving vertically downwards along the soil profile and eventually being discharged from the topsoil or root zone is the key physical process for desalination and alkali reduction in soda saline-alkali soil.

[0030] In a first aspect, the present invention provides: a soda-based rhizosphere amendment granule for direct-seeded maize in saline-alkali dryland fields, comprising a rapid-release component F and a slow-release component S, wherein the rapid-release component F, by mass percentage, comprises the following components: Acidic calcium source material 35-55%; Iron salts 3-10%; Fine-grained biochar 10-20%; 2-6% lignin sulfonate; 1-8% organic acids or organic acid salts; Adhesive 1-5%; and Inert mineral filler allowance; The sustained-release component S, by mass percentage, comprises the following components: Calcium source materials: 30-50%; Calcium-based bentonite 10-25%; Humic acid 8-15%; Mesoporous carbon materials: 10-20%; Adhesive 1-4%; and Inert mineral filler allowance.

[0031] Preferably, the acidic calcium source material in the rapid-release component F is selected from any value or range between 35% and 55% by mass percentage, specifically from: 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55% or a range between the two.

[0032] More preferably, the acidic calcium source material in the rapid-release component F is 45% by mass percentage.

[0033] Preferably, the iron salt in the rapid-release component F is selected from any value or range between 3% and 10% by mass percentage, specifically from: 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range between two of them.

[0034] More preferably, the iron salt in the rapid-release component F is 5% by mass percentage.

[0035] Preferably, the fine biochar in the rapid-release component F is selected from any value or range between 10-20% by mass percentage, specifically from: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or a range between the two.

[0036] More preferably, the fine biochar in the rapid-release component F is 15% by mass percentage.

[0037] Preferably, the lignin sulfonate in the rapid-release component F is selected from any value or range between 2% and 6% by mass percentage, specifically from: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6% or a range between two of them.

[0038] More preferably, the lignin sulfonate in the rapid-release component F is 3% by mass percentage.

[0039] Preferably, the organic acid or organic acid salt in the rapid-release component F is selected from any value or range between 1% and 8% by mass percentage, specifically from: 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8% or a range between the two.

[0040] More preferably, the organic acid or organic acid salt in the rapid-release component F is 4% by mass percentage.

[0041] Preferably, the binder in the fast-release component F is selected from any value or range between 1% and 5% by mass percentage, specifically from: 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or a range between the two.

[0042] More preferably, the binder in the rapid-release component F is 5% by mass percentage.

[0043] Preferably, the calcium source material in the sustained-release component S is selected from any value or range between 30% and 50% by mass percentage, specifically from: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or a range between the two.

[0044] More preferably, the calcium source material in the sustained-release component S is 35% by mass percentage.

[0045] Preferably, the calcium-based bentonite in the slow-release component S is selected from any value or range between 10% and 25% by mass percentage, specifically from: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25% or a range between the two.

[0046] More preferably, the calcium-based bentonite in the slow-release component S is 20% by mass percentage.

[0047] Preferably, the humic acid in the slow-release component S is selected from any value or range between 8% and 15% by mass percentage, specifically from: 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or a range between the two.

[0048] More preferably, the humic acid in the slow-release component S is 12% by mass percentage.

[0049] Preferably, the mesoporous carbon material in the sustained-release component S is selected from any value or range between 10-20% by mass percentage, specifically from: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or a range between the two.

[0050] More preferably, the mesoporous carbon material in the sustained-release component S comprises 15% by mass percentage.

[0051] Preferably, the binder in the sustained-release component S is selected from any value or range between 1% and 4% by mass percentage, specifically from: 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or a range between the two.

[0052] More preferably, the binder in the sustained-release component S is 4% by mass.

[0053] Preferably, the mass ratio of the rapid-release component F to the sustained-release component S is selected from any value or range between 1:1.5 and 3.0, specifically from: 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3.0 or a range between two of them.

[0054] More preferably, the mass ratio of the rapid-release component F to the sustained-release component S is selected from any value or range between 1:1.8 and 2.5, specifically from: 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5 or a range between the two.

[0055] More preferably, the mass ratio of the rapid-release component F to the sustained-release component S is 1:2.

[0056] Preferably, the acidic calcium source material is a calcium-based material that has been impregnated and cured with an organic acid solution.

[0057] Preferably, the calcium source material is selected from one or more of phosphogypsum, desulfurized gypsum, natural gypsum, or calcium sulfate.

[0058] More preferably, the calcium source material is phosphogypsum.

[0059] Preferably, the preparation of the acidic calcium source material specifically involves: The calcium source material is mixed with citric acid solution, stirred evenly, allowed to stand for aging, and then dried at low temperature to obtain the final product.

[0060] Preferably, the mass fraction of the citric acid solution is selected from any value or range between 3% and 8%, specifically from: 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, or a range between two of them.

[0061] More preferably, the citric acid solution has a mass fraction of 5%.

[0062] Preferably, the liquid-to-solid ratio of the citric acid solution to the calcium source material is selected from any value or range between 0.20-0.35L:1kg, specifically from: 0.20L:1kg, 0.25L:1kg, 0.28L:1kg, 0.30L:1kg, 0.35L:1kg or a range between the two.

[0063] More preferably, the liquid-to-solid ratio of the citric acid solution to the calcium source material is 0.28L:1kg.

[0064] Preferably, the curing time is selected from any value or range between 12 and 24 hours, specifically from: 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours or a range between the two.

[0065] More preferably, the maturation time is 18 hours.

[0066] Preferably, the drying temperature is any value or range between 45-60°C, specifically selected from: 45°C, 50°C, 55°C, 60°C or a range between two of them.

[0067] More preferably, the drying temperature is 55°C.

[0068] Preferably, the drying process specifically involves reducing the moisture content of the acidic calcium source material to 5%-12%.

[0069] More preferably, the drying process specifically involves reducing the moisture content of the acidic calcium source material to 8%.

[0070] Preferably, the iron salt is selected from one or more of ferric sulfate, ferrous sulfate, and polyferric sulfate.

[0071] More preferably, the iron salt is ferric sulfate.

[0072] Preferably, the organic acid is selected from one or more of citric acid, malic acid, tartaric acid, oxalic acid, acetic acid, lactic acid, and fumaric acid.

[0073] Preferably, the organic acid is a compound system composed of citric acid and malic acid in a mass ratio of 2:1.

[0074] Preferably, the organic acid salt is selected from one or more of citrate, malate, tartrate and humate.

[0075] More preferably, the organic acid salt is calcium citrate.

[0076] Preferably, the binder is selected from one or more of starch-based binders, lignin-based binders, carboxymethyl cellulose, and alginate.

[0077] More preferably, the adhesive is a starch-based adhesive.

[0078] Preferably, the inert mineral filler is selected from one or more of bentonite, zeolite powder, diatomite, and attapulgite.

[0079] More preferably, the inert mineral filler is bentonite and / or zeolite powder.

[0080] Preferably, the mesoporous carbon material is selected from one or more of mesoporous biochar, activated carbon, bamboo-based porous carbon, straw-based porous carbon, and carbon-based molecular sieves.

[0081] More preferably, the mesoporous carbon material is mesoporous biochar.

[0082] Preferably, the particle size of the fine biochar is selected from any value or range between 0.05-0.25 mm, specifically from: 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, or a range between two of these.

[0083] More preferably, the particle size of the fine biochar is 0.15 mm.

[0084] Preferably, the specific surface area of ​​the fine-grained biochar is not less than any value or range of 80 m² / g, specifically selected from: 80 m² / g, 90 m² / g, 100 m² / g, 110 m² / g, 120 m² / g, 130 m² / g, 150 m² / g or a range between the two.

[0085] More preferably, the specific surface area of ​​the fine-grained biochar is 120 m² / g.

[0086] Preferably, the pore size of the mesoporous carbon material is selected from any value or range between 2 and 50 nm, specifically from: 2 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm or a range between the two.

[0087] More preferably, the pore size of the mesoporous carbon material is 20 nm.

[0088] Preferably, the specific surface area of ​​the mesoporous carbon material is not less than any value or range of 120 m² / g, specifically selected from: 120 m² / g, 150 m² / g, 180 m² / g, 200 m² / g, 250 m² / g, 300 m² / g or a range between the two.

[0089] More preferably, the specific surface area of ​​the mesoporous carbon material is 180 m² / g.

[0090] Preferably, the preparation method of the fast-release component F is as follows: after crushing, sieving, and mixing the raw materials evenly, water is added to adjust the moisture content, and then the raw materials are extruded, granulated, rolled, dried, and sieved to obtain fast-release particles.

[0091] Preferably, the fineness of the pulverization in the preparation method of the fast-release component F is selected from any value or range between 80 and 120 mesh, specifically from 80 mesh, 100 mesh, 120 mesh or a range between the two.

[0092] More preferably, the fineness of the pulverization in the preparation method of the fast-release component F is 100 mesh.

[0093] Preferably, the sieve used in the preparation method of the fast-release component F is selected from any value or range between 80 and 120 mesh, specifically from 80 mesh, 100 mesh, 120 mesh or a range between the two.

[0094] More preferably, the sieve used in the preparation method of the rapid-release component F is a 100-mesh sieve.

[0095] Preferably, the purpose of adding water in the preparation method of the fast-release component F is to adjust the water content of the mixed raw materials.

[0096] Preferably, the moisture content is selected from any value or range between 12% and 22%, specifically from: 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22% or a range between two of them.

[0097] More preferably, the moisture content is 20%.

[0098] Preferably, the specific operations of extrusion granulation and spheroidization in the preparation method of the fast-release component F are as follows: the conditioned mixture is fed into a screw extruder to extrude short columnar wet particles; then spheroidization, drying and sieving are performed to obtain the final product.

[0099] Preferably, the extrusion particle size in the preparation method of the fast-release component F is selected from any value or range between 0.4-0.8 mm, specifically from: 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm or a range between the two.

[0100] More preferably, the extrusion particle size in the method for preparing the fast-release component F is 0.6 mm.

[0101] Preferably, the spheronization rate in the preparation method of the rapid-release component F is selected from any value or range between 300-600 r / min, specifically from: 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min, 600 r / min or a range between the two.

[0102] More preferably, the spheroidizing rate in the preparation method of the rapid-release component F is 450 r / min.

[0103] Preferably, the spheroidizing time in the preparation method of the rapid-release component F is selected from any value or range between 3 and 8 min, specifically from: 3 min, 4 min, 5 min, 6 min, 7 min, 8 min or a range between the two.

[0104] More preferably, the spheroidizing time in the preparation method of the rapid-release component F is 5 minutes.

[0105] Preferably, the drying temperature in the preparation method of the rapid-release component F is selected from any value or range between 40-65℃, specifically from: 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, 61℃, 62℃, 63℃, 64℃, 65℃ or a range between two of them.

[0106] More preferably, the drying temperature in the preparation method of the fast-release component F is 55°C.

[0107] Preferably, the moisture content of the dried particles in the preparation method of the fast-release component F is any value or range between 5% and 12%, specifically selected from: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12% or a range between the two.

[0108] More preferably, the moisture content of the dried particles in the preparation method of the fast-release component F is up to 8%.

[0109] Preferably, the particle size of the fast-release component F is selected from any value or range between 0.3-0.8 mm, specifically from: 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm or a range between the two.

[0110] More preferably, the particle size of the fast-release component F is selected from any value or range between 0.4-0.7 mm, specifically from: 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm or a range between the two.

[0111] More preferably, the particle size of the fast-release component F is 0.5 mm.

[0112] Preferably, the preparation method of the sustained-release component S is as follows: after crushing, sieving, and mixing the raw materials evenly, water is added to adjust the moisture content, and the sustained-release particles are obtained by extrusion granulation, spheroidization, drying, and sieving.

[0113] Preferably, the fineness of the pulverization in the preparation method of the sustained-release component S is selected from any value or range between 60 and 100 mesh, specifically from: 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh or a range between the two.

[0114] More preferably, the fineness of the pulverization in the preparation method of the sustained-release component S is 80 mesh.

[0115] Preferably, the sieve used in the preparation method of the sustained-release component S is selected from any value or range between 60 and 100 mesh, specifically from 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh or a range between the two.

[0116] More preferably, the sieve used in the preparation method of the sustained-release component S is 80 mesh.

[0117] Preferably, the purpose of adding water in the preparation method of the slow-release component S is to adjust the water content of the mixed raw materials.

[0118] Preferably, the moisture content is selected from any value or range between 12% and 22%, specifically from: 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22% or a range between two of them.

[0119] More preferably, the moisture content is 18%.

[0120] Preferably, the specific operations of extrusion granulation and spheroidization in the preparation method of the slow-release component S are as follows: the conditioned mixture is fed into an extrusion granulator to extrude short columnar wet particles; then spheroidized, dried and sieved to obtain the final product.

[0121] Preferably, the extrusion particle size in the preparation method of the sustained-release component S is selected from any value or range between 1.5-2.5 mm, specifically from: 1.5 mm, 1.55 mm, 1.6 mm, 1.65 mm, 1.7 mm, 1.75 mm, 1.8 mm, 2 mm, 2.1 mm, 2.15 mm, 2.2 mm, 2.25 mm, 2.3 mm, 2.35 mm, 2.4 mm, 2.45 mm, 2.5 mm, or a range between two of them.

[0122] More preferably, the extrusion particle size in the method for preparing the sustained-release component S is 2.0 mm.

[0123] Preferably, the spheronization rate in the preparation method of the sustained-release component S is selected from any value or range between 200-500 r / min, specifically from: 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min or a range between the two.

[0124] More preferably, the spheroidizing rate in the preparation method of the sustained-release component S is 350 r / min.

[0125] Preferably, the spheroidizing time in the preparation method of the sustained-release component S is selected from any value or range between 5 and 12 min, specifically from: 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min or a range between the two.

[0126] More preferably, the spheroidizing time in the preparation method of the sustained-release component S is 8 minutes.

[0127] Preferably, the drying temperature in the preparation method of the sustained-release component S is selected from any value or range between 40-65℃, specifically from: 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, or a range between two of these.

[0128] More preferably, the drying temperature in the preparation method of the sustained-release component S is 50°C.

[0129] Preferably, the moisture content of the dried particles in the preparation method of the sustained-release component S is any value or range between 5% and 12%, specifically selected from: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12% or a range between the two.

[0130] More preferably, the moisture content of the dried particles in the preparation method of the sustained-release component S is up to 10%.

[0131] Preferably, the sieving in the preparation method of the sustained-release component S uses a sieve with a 1.2-2.8 mm aperture, or a 7-16 mesh sieve, to collect particles with a diameter of 1.2-2.8 mm.

[0132] Preferably, the particle size of the sustained-release component S is selected from any value or range between 1.2 and 2.8 mm, specifically from: 1.2 mm, 1.5 mm, 2 mm, 2.3 mm, 2.35 mm, 2.4 mm, 2.45 mm, 2.5 mm, 2.55 mm, 2.6 mm, 2.65 mm, 2.7 mm, 2.75 mm, 2.8 mm, or a range between two of them.

[0133] More preferably, the particle size of the sustained-release component S is selected from any value or range between 1.5-2.5 mm, specifically from: 1.5 mm, 2 mm, 2.3 mm, 2.35 mm, 2.4 mm, 2.45 mm, 2.5 mm or a range between the two.

[0134] More preferably, the particle size of the sustained-release component S is 2.0 mm.

[0135] Based on further solutions to the technical problems of this invention, or simultaneous solutions to multiple technical problems, in this invention... invention The preferred solutions provided in the first aspect include: The first priority solution is a soda-based rhizosphere amendment granule for direct-seeded maize in saline-alkali dryland fields. This solution addresses the technical problems of "large dosage and mismatch between the effective window and the maize emergence stage" and further solves the technical problems of "insufficient calcium supply in the later stage and inaccurate micro-zone regulation of the rhizosphere in the sowing furrow".

[0136] Secondly, the present invention provides a method for applying the above-mentioned modified granules, comprising the following steps: When directing corn in moderately to severely saline-alkali dryland fields, create corn planting furrows and apply the fast-release component F to the planting zone beside and / or above the corn seeds; apply the slow-release component S to the area below and / or to the lateral root extension zone of the corn seeds. After sowing, cover with soil and compact, and manage water according to the conventional cultivation methods for dryland corn.

[0137] Preferably, the total application rate of the improved granules is 200-400 kg / mu.

[0138] Preferably, the improved particles are applied to direct-seeded corn plots in moderately to severely saline-alkali dryland fields with a soil pH of 9.0-10.5 and an ESP of 20-45% in the 0-20cm soil layer before sowing.

[0139] Preferably, the application rate of the improved particles is adjusted according to different soil conditions, as follows: When the soil conditions are pH 9.0-9.5 and ESP 20%-30%, i.e., moderately soda-saline dryland corn direct seeding plots, the total application rate of improved grains is 200-280 kg / mu, of which the mass ratio of fast-release component F to slow-release component S is 1:(1.5-2.0). When the soil conditions are pH 9.5-10.0 and ESP 30%-40%, i.e., moderate to severe soda saline-alkali dryland corn direct seeding plots, the total application rate of improved grains is 280-350 kg / mu, of which the mass ratio of fast-release component F to slow-release component S is 1:(2.0-2.5). When the soil conditions are pH>10 or ESP>40%, i.e., severely soda saline-alkali dryland corn direct seeding plots, the total application rate of improved grains is 350-400 kg / mu, of which the mass ratio of fast-release component F to slow-release component S is 1:(2.5-3.0).

[0140] More preferably, the application rate of the improved particles is adjusted according to different soil conditions, as follows: When the soil conditions are pH 9.0-9.5 and ESP 20%-30%, i.e., moderately soda saline-alkali dryland corn direct seeding plots, the total application rate of improved grains is 240 kg / mu, of which the mass ratio of fast-release component F to slow-release component S is 1:1.8. When the soil conditions are pH 9.5-10.0 and ESP 30%-40%, i.e., moderate to severe soda saline-alkali dryland corn direct seeding plots, the total application rate of improved grains is 320 kg / mu, of which the mass ratio of fast-release component F to slow-release component S is 1:2.2. When the soil conditions are pH>10 or ESP>40%, i.e., severely soda saline-alkali dryland corn direct seeding plots, the total application rate of improved granules is 380 kg / mu, of which the mass ratio of fast-release component F to slow-release component S is 1:2.8.

[0141] Preferably, the width of the corn planting furrow is 5-10cm, and more preferably 6-8cm.

[0142] Preferably, the soil covering thickness of the corn planting furrow is 3-6 cm, and more preferably 4-5 cm. This range takes into account the problems of easy moisture loss in the surface layer of soda-saline dryland fields in Northeast China in spring, the impact of excessively thick soil covering on seedling emergence, and the tendency of excessively thin soil covering to cause salt return and crusting.

[0143] Preferably, the seeding zone of the fast-release component F is specifically: applied 0-2 cm to the side of the corn seed and / or 1-3 cm above the corn seed.

[0144] Preferably, the slow-release component S is applied to the sowing zone area, specifically in the area where the main root extends 3-6 cm below and / or 2-5 cm to the side below the corn seed.

[0145] The acidic calcium source material in the fast-release component F not only provides some of the available Ca²⁺ + It also reduces local alkalinity through the neutralizing ability of residual organic acid radicals and acidic treatment; the weakly acidic environment generated by the hydrolysis of ferric salts can participate in alkalinity regulation and promote Na+ metabolism through the influence of ferric hydroxyl species on carbonate / bicarbonate and colloidal surface charge. + Desorption; fine-grained biochar can improve the porosity and buffering environment near the seed, lignin sulfonates can disperse, complex, and regulate particle disintegration, and organic acids or organic acid salts can regulate local pH. The calcium source material in the slow-release component S can continuously provide calcium. 2+ Calcium-based bentonite can provide calcium and improve soil structure, humic acid can improve aggregates and rhizosphere buffering capacity, and mesoporous carbon materials can regulate water conduction and calcium. 2+ Release process.

[0146] The binders in the fast-release component F and the slow-release component S can granulate and control particle strength, while the inert mineral fillers can adjust the particle structure and release rate.

[0147] The rapid-release component F is located beside and / or above the maize seed, has a small particle size, and releases rapidly. Within 12-36 hours after sowing, component F releases its acid-neutralizing ability, reducing the pH and alkalinity in the seed vicinity and mitigating HCO3. / CO3 2 The dominant alkaline stress provides a low-alkalinity microenvironment for seed water absorption and germination, radicle breakthrough and seedling emergence.

[0148] The slow-release component S is located below and / or to the side of the maize seed, has a larger particle size, and releases at a slower rate. Within 5-15 days after sowing, component S continuously releases water-soluble calcium. 2+ It acts on the area below the main root of corn, promoting the adsorption of Na by soil colloids. + by Ca 2+ Replacement, and in conjunction with precipitation or irrigation, to reduce Na + Migrate downwards.

[0149] The fast-release component F and the slow-release component S are not characterized by simple isotopic mixing, but rather by differences in particle size, release window, and application location, respectively corresponding to the main obstacles in the seed vicinity and the primary root penetration area, forming a "rapid alkali reduction in the upper part - Na" structure. + Desorption - continuous calcium supply from the lower part - Ca 2+ -Na + Replacement of Na + The rhizosphere microregion regulatory pathway of "downward migration and discharge".

[0150] The beneficial effects of this invention are as follows: (1) It pioneered a spatiotemporal partitioning control technology system, breaking through the technical bias of full-layer improvement. This invention is the first to couple four elements—particle size classification, material release window, spatial location of the sowing furrow, and maize root development stage—into a design that breaks away from the conventional approach of broadcasting and mixing materials across the entire field. By matching the release rate to particle size differences and matching the root development needs to spatial positioning, the limited amount of amendment material is precisely applied to the key areas of seed germination and taproot development. The dosage is only 1 / 10 to 1 / 12 of existing broadcasting techniques, yet it achieves superior seedling emergence and improvement results.

[0151] (2) The rapid release layer precisely matches the germination window, simultaneously overcoming the dual obstacles of alkali damage and skin formation. The fast-release component F is positioned near the seed and, through the synergistic effect of acidic calcium sources, iron salts, and organic acids, rapidly neutralizes rhizosphere carbonate and lowers pH within 12-36 hours after sowing, thus relieving the toxicity of high alkalinity to the radicle. At the same time, in conjunction with the porous structure of fine-grained biochar, it weakens surface soil compaction and reduces crust strength, thus simultaneously addressing emergence obstacles from both chemical and physical perspectives, avoiding the risk of seed burning from direct contact between the fast-release material and the seed.

[0152] (3) The slow-release layer continuously supplies calcium during the ligation period to achieve deep sodium replacement. The slow-release component S is located in the root zone and, through the controlled release of calcium-based bentonite, humic acid, and mesoporous carbon, steadily releases calcium ions 5–15 days after sowing, perfectly coinciding with the critical period of rapid root elongation in maize. More importantly, the slightly acidic environment created by the upper component F, as water infiltrates downwards, significantly promotes the dissolution of gypsum-based calcium sources in the lower layers, increasing calcium ion release efficiency by more than 30% compared to a single slow-release material, achieving more thorough Ca²⁺ release. + -Na + Displacement.

[0153] (4) The upper and lower layers work together to form a closed loop, producing unexpected technical effects. The upper layer rapidly desorbs colloidal adsorbed sodium ions, while the lower layer continuously provides calcium ions to complete the replacement. Combined with field water movement, the replaced sodium ions can migrate directionally out of the root zone with the water. Field experiments have confirmed that the seedling emergence rate and sodium ion leaching amount of this invention are significantly higher than the linear additive effect of fast-release and slow-release materials, representing a synergistic effect that cannot be predicted in advance by those skilled in the art.

[0154] (5) The process is simple and suitable for field production, and is easy to promote. This invention does not require complex processes such as coating or microbial loading; it can be prepared simply through conventional extrusion granulation and sieving. The application method can be completed simultaneously with a corn planter, without the need for additional agronomic procedures, making it suitable for large-scale promotion and application in the soda-saline-alkali arid areas of Northeast and Northwest China. Attached Figure Description

[0155] Figure 1 The cumulative sodium ion leaching amount for different treatments. Detailed Implementation

[0156] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0157] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0158] Table 1

[0159] Basic Example 1: Preparation of Acidic Calcium Source Material The preparation method includes the following steps: The calcium source material was mixed with a 5% citric acid solution at a liquid-to-solid ratio of 0.28 L: 1 kg. After stirring evenly, the mixture was allowed to stand and mature for 18 hours, and then dried at a low temperature of 55°C to reduce the moisture content of the acidic calcium source material to 8%. The pH of the acidic calcium source material was 3.5.

[0160] The acidic calcium source material was tested for As, Cd, Pb, Cr, Hg, total fluorine, water-soluble fluorine, and 22... 6 The specific detection methods for Ra and total phosphorus content are as follows: Heavy metals (As, Cd, Pb, Cr, Hg): determined by microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) according to GB / T23349-2009 standard. Hg and As were simultaneously verified by atomic fluorescence spectrometry.

[0161] Total fluoride and water-soluble fluoride: In accordance with the NY / T2975-2016 standard, total fluoride was determined by the alkali fusion-fluoride ion selective electrode method; water-soluble fluoride was extracted at a liquid-solid ratio of 10:1 (mL:g) and then determined by the fluoride ion selective electrode method.

[0162] Radionuclides²² 6 Ra: Measured using a high-purity germanium gamma spectrometer, in accordance with GB6566-2010 standard.

[0163] Total phosphorus (as P2O5): determined by vanadium molybdenum yellow spectrophotometry according to GB / T8573-2017 standard.

[0164] The test results were as follows: As 2.4 mg / kg, Cd 0.21 mg / kg, Pb 8.6 mg / kg, Cr 15.2 mg / kg, Hg 0.03 mg / kg, total fluoride 0.48%, water-soluble fluoride 18.5 mg / kg,²² 6 Ra 92Bq / kg, total phosphorus 0.62% (calculated as P2O5).

[0165] Basic Example 2: Preparation of Acidic Calcium Source Material The preparation method includes the following steps: The calcium source material was mixed with a 3% citric acid solution at a liquid-to-solid ratio of 0.35 L: 1 kg. After stirring evenly, the mixture was allowed to stand and mature for 12 hours, and then dried at a low temperature of 45°C to reduce the moisture content of the acidic calcium source material to 5%. The pH of the acidic calcium source material was 3.6.

[0166] The acidic calcium source material was tested for As, Cd, Pb, Cr, Hg, total fluorine, water-soluble fluorine, and 22... 6 The specific detection methods for Ra and total phosphorus content are as follows: Heavy metals (As, Cd, Pb, Cr, Hg): determined by microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) according to GB / T23349-2009 standard. Hg and As were simultaneously verified by atomic fluorescence spectrometry.

[0167] Total fluoride and water-soluble fluoride: In accordance with the NY / T2975-2016 standard, total fluoride was determined by the alkali fusion-fluoride ion selective electrode method; water-soluble fluoride was extracted at a liquid-solid ratio of 10:1 (mL:g) and then determined by the fluoride ion selective electrode method.

[0168] Radionuclides²² 6 Ra: Measured using a high-purity germanium gamma spectrometer, in accordance with GB6566-2010 standard.

[0169] Total phosphorus (as P2O5): determined by vanadium molybdenum yellow spectrophotometry according to GB / T8573-2017 standard.

[0170] The test results were as follows: As 2.7 mg / kg, Cd 0.25 mg / kg, Pb 9.2 mg / kg, Cr 16.8 mg / kg, Hg 0.04 mg / kg, total fluoride 0.52%, water-soluble fluoride 21.3 mg / kg, and so on. 6 Ra 98Bq / kg, total phosphorus 0.58% as P2O5.

[0171] Basic Example 3: Preparation of Acidic Calcium Source Material The preparation method includes the following steps: The calcium source material was mixed with an 8% citric acid solution at a liquid-to-solid ratio of 0.20 L: 1 kg. After stirring evenly, the mixture was allowed to stand and mature for 24 hours, and then dried at a low temperature of 60°C to reduce the moisture content of the acidic calcium source material to 12%. The pH of the acidified calcium source material was 3.8.

[0172] The acidic calcium source material was tested for As, Cd, Pb, Cr, Hg, total fluorine, water-soluble fluorine, and 22... 6 The specific detection methods for Ra and total phosphorus content are as follows: Heavy metals (As, Cd, Pb, Cr, Hg): determined by microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) according to GB / T23349-2009 standard. Hg and As were simultaneously verified by atomic fluorescence spectrometry.

[0173] Total fluoride and water-soluble fluoride: In accordance with the NY / T2975-2016 standard, total fluoride was determined by the alkali fusion-fluoride ion selective electrode method; water-soluble fluoride was extracted at a liquid-solid ratio of 10:1 (mL:g) and then determined by the fluoride ion selective electrode method.

[0174] Radionuclides²² 6 Ra: Measured using a high-purity germanium gamma spectrometer, in accordance with GB6566-2010 standard.

[0175] Total phosphorus (as P2O5): determined by vanadium molybdenum yellow spectrophotometry according to GB / T8573-2017 standard.

[0176] The test results were as follows: As 2.1 mg / kg, Cd 0.19 mg / kg, Pb 7.8 mg / kg, Cr 14.5 mg / kg, Hg 0.03 mg / kg, total fluoride 0.46%, water-soluble fluoride 16.9 mg / kg,²² 6 Ra 89Bq / kg, total phosphorus as P2O5 0.65%.

[0177] Example 1 Fast-release component F formulation (mass percentage): 45% acidic phosphogypsum prepared in basic example 1, 5% ferric sulfate, 15% fine biochar, 3% sodium lignosulfonate, 4% calcium citrate, 23% bentonite, and 5% starch-based binder.

[0178] Preparation process: All raw materials are crushed to 100 mesh, passed through a 100 mesh sieve, mixed for 12 minutes, water is added to adjust the moisture content to 20%, and fed into a screw extruder to granulate short cylindrical wet granules through a 0.6 mm aperture template; then fed into a rounding machine and rounded at 450 r / min for 5 minutes; dried at 55℃ until the granule moisture content is 8%, and sieved through 0.3 mm and 0.8 mm standard sieves to obtain fast-release component F with a particle size of about 0.5 mm.

[0179] Slow-release component S formulation (by weight): phosphogypsum 35%, calcium-based bentonite 20%, humic acid 12%, mesoporous biochar 15%, zeolite powder 14%, starch-based binder 4%.

[0180] Preparation process: Crush all raw materials to 80 mesh, pass through an 80 mesh sieve and mix for 15 min, add water to adjust the moisture content to 18%, granulate by extrusion through a 2.0 mm aperture template; roll into rounds at 350 r / min for 8 min; dry at 50℃ until the particle moisture content is 10%, and sieve through 1.2 mm and 2.8 mm standard sieves to obtain a slow-release component S with a particle size of about 2.0 mm.

[0181] In this embodiment, the mass ratio of the fast-release component F to the sustained-release component S is 1:2; The specific application area for the fast-release component F is 1-3 cm above the corn seeds; The slow-release component S is specifically applied to the seeding zone 3-6 cm below the corn seeds.

[0182] Example 2 Fast-release component F formulation: 55% acidic phosphogypsum, 10% ferric sulfate, 10% fine biochar, 2% sodium lignosulfonate, 1% calcium citrate, 1% starch-based binder, and 21% bentonite prepared in Basic Example 2.

[0183] Preparation process: The powder is crushed through a 100-mesh sieve, mixed for 10 minutes, and the moisture content is adjusted to 18%. It is then extruded through a 0.5 mm template, rolled into balls at 500 r / min for 4 minutes, dried at 55℃ to a moisture content of 8%, and sieved to obtain a fast-release component F with a particle size of about 0.4 mm.

[0184] Slow-release component S formulation: 50% phosphogypsum, 25% calcium-based bentonite, 8% humic acid, 10% mesoporous biochar, 1% starch-based binder, and 6% zeolite powder.

[0185] Preparation process: The powder is crushed through an 80-mesh sieve, mixed for 15 minutes, and the moisture content is adjusted to 17%. It is then extruded through a 2.5 mm template, rolled into balls at 300 r / min for 10 minutes, dried at 50℃ to a moisture content of 10%, and sieved to obtain a slow-release component S with a particle size of about 2.5 mm.

[0186] In this embodiment, the mass ratio of the fast-release component F to the sustained-release component S is 1:2.5; The specific application area for the fast-release component F is 1-3 cm above the corn seeds; The slow-release component S is specifically applied to the seeding zone 3-6 cm below the corn seeds.

[0187] Example 3 Fast-release component F formulation: 35% acidic phosphogypsum, 3% ferric sulfate, 20% fine biochar, 6% sodium lignosulfonate, 8% calcium citrate, 5% starch-based binder, and 23% bentonite prepared in basic example 3.

[0188] Preparation process: The powder is crushed through a 100-mesh sieve, mixed for 15 minutes, and the moisture content is adjusted to 22%. It is then extruded through a 0.7 mm template, rolled at 400 r / min for 6 minutes, dried at 55℃ to a moisture content of 8%, and sieved to obtain a fast-release component F with a particle size of about 0.7 mm.

[0189] Slow-release component S formulation: 30% phosphogypsum, 10% calcium-based bentonite, 15% humic acid, 20% mesoporous biochar, 4% starch-based binder, and 21% zeolite powder.

[0190] Preparation process: The powder is crushed through an 80-mesh sieve, mixed for 18 minutes, and the moisture content is adjusted to 20%. It is then extruded through a 1.5mm template, rolled at 400r / min for 7 minutes, dried at 50℃ to a moisture content of 10%, and sieved to obtain a slow-release component S with a particle size of about 1.5mm.

[0191] In this embodiment, the mass ratio of the fast-release component F to the sustained-release component S is 1:1.8; The specific application area for the fast-release component F is 1-3 cm above the corn seeds; The slow-release component S is specifically applied to the seeding zone 3-6 cm below the corn seeds.

[0192] Comparative Example 1 In this comparative example, the F / S mass ratio is outside the range. The formulation and preparation method are the same as in Example 1, except that the mass ratio of the fast-release component F to the sustained-release component S is adjusted to 1:0.5 (the proportion of fast-release is too high, exceeding the range of 1:1.5~3.0 of this invention). The application method is the same as the zoned and targeted application in Example 1, and the total application amount is the same as in Example 1.

[0193] In this comparative example, the mass ratio of the fast-release component F to the sustained-release component S is 1:0.5.

[0194] Purpose of this invention: To verify the technical rationality of the F / S mass ratio range defined in this invention, and to prove that an imbalance in the ratio will lead to insufficient calcium supply and incomplete sodium replacement in the later stages.

[0195] Comparative Example 2 This comparative example involves the application of F / S mixed materials in the same layer. All raw materials of F and S from Example 1 were uniformly mixed at a mass ratio of 1:2 and then granulated. The particle size was controlled to be 1.2 mm, and the preparation process was the same as in Example 1. During application, the mixed granules were placed in the same layer as the corn seeds in the planting furrow, without any upper or lower partitioning.

[0196] Purpose of the setup: To verify the synergistic effect of "spatial positioning + particle size classification + release window matching" and to prove that simple mixing cannot achieve spatiotemporal synergy between alkalinity reduction in the seed vicinity and calcium supply in the main root zone.

[0197] Comparative Example 3 This comparative example uses a conventional soil amendment applied topically. The amendment was prepared according to the technical scheme of CN121652813A: by mass percentage, it consists of 80% citric acid-treated gypsum, 10% commercial organic fertilizer, 5% fine biochar, 3% humic acid, and 2% starch-based binder, mixed and granulated to obtain particles of 1.0~1.5mm. The application method is to evenly spread it across the entire field and then rotary till it into the 0~20cm soil layer. The recommended application rate is 3000kg / mu (45t / hectare) according to current technology.

[0198] Purpose of this invention: To highlight the technical advantages of reducing dosage and increasing efficiency in contrast to the low-dosage, targeted application scheme of this invention.

[0199] Comparative Example 4 This comparative example involves the application of only the slow-release component S, using only the slow-release component S from Example 1. The total application amount is the same as that in Example 1, and it is applied entirely to the main root zone 3-6 cm below the seed. No fast-release component F is applied.

[0200] Purpose of the experiment: To verify the irreplaceable role of the rapid-release component F in early alkalinity reduction and germination promotion, as well as the synergistic promoting effect of F on calcium release from S.

[0201] Comparative Example 5 This comparative example involves the application of only the fast-release component F, using only the fast-release component F from Example 1. The total application amount is the same as that in Example 1, and it is applied entirely to the main root zone 3-6 cm above the seed. No slow-release component S is applied.

[0202] Purpose of the setup: To verify the effect of slow-release component S on promoting the adsorption of Na by soil colloidal particles. + by Ca 2+ The irreplaceability of the substitution and the synergistic promoting effect of F on S calcium release.

[0203] Detection of release curve and verification of fast / slow-release compatibility in Example 1 1. Testing Method A simulated sodium bicarbonate-alkali solution was prepared using sodium bicarbonate and sodium carbonate, with a pH of 9.8 ± 0.1 and HCO3- content... The concentration was 10 mmol / L. Weigh 2.00 g of the sample and add 200 mL of simulated sodium bicarbonate solution, with a solid-liquid ratio of 1:100 (g / mL). Each treatment was repeated in triplicate. The sample was placed in a constant temperature shaking incubator at 25 ± 1 °C and a shaking frequency of 150 r / min. Samples were taken at 6 h, 12 h, 24 h, 48 h, 5 d, 9 d, 15 d, and 30 d, with an equal volume of simulated solution of the same concentration added after each sampling.

[0204] The sample solution was centrifuged at 4000 r / min for 10 min and then filtered through a 0.45 μm filter membrane. The acid neutralization amount was determined by acid-base titration, and the acid neutralization release rate was calculated as At / A∞ × 100%, where At is the amount of acid neutralized released at time t, and A∞ is the total amount of acid neutralized after complete release. Water-soluble Ca 2+ The pH of the system was determined by EDTA complexometric titration, atomic absorption spectrophotometry, or ICP-OES. The pH of the system was determined using a pH meter calibrated with standard buffer solutions at pH 4.00, 6.86, and 9.18.

[0205] Data are expressed as mean ± standard deviation, with n=3 replicates; one-way ANOVA was used, and differences between treatments were analyzed using Duncan's method or LSD method for multiple comparisons, with a significance level of 1. P <0.05. Different lowercase letters represent differences after different treatments at the same time point. P <0.05 level.

[0206] The examples and comparative studies used the same number of replicates, the same sampling time, the same measurement method, and the same statistical method.

[0207] 2. Experimental Results Results analysis: Early acid neutralization capacity: The 12h release rate of single fast-release F and D1 (with too high proportion of fast release) was the highest, but the total calcium release of D1 over 30 days was significantly lower than that of the embodiment of the present invention due to insufficient slow-release calcium source.

[0208] Synergistic effect of calcium release: Based on the linear superposition of F:S=1:2, the theoretical calcium release in 30 days is about 57.6 mg / g, while the actual T1 of this invention reaches 86.4 mg / g, an increase of about 50%, which proves that the acidic environment in the upper layer significantly promotes the dissolution of the calcium source in the lower layer. The two have a clear synergistic effect, rather than a simple superposition.

[0209] Mixed and whole-field treatments have poor effects: D2 mixed application in the same layer results in a significant decrease in both acid efficiency and calcium release efficiency due to premature neutralization of acid and calcium; D3 whole-field broadcasting results in low release concentration due to material dispersion, and its effect is far worse than that of fixed application.

[0210] Table 2

[0211] Note: Different lowercase letters in the same column indicate significant differences (P < 0.05).

[0212] Example 2: Ca detection in soil column 2+ -Na + Displacement and Na + Migration and effusion validation 1. Testing Method PVC soil columns with an inner diameter of 10 cm and a height of 40 cm were used to fill a 0-20 cm layer of soda-saline-alkali dryland soil. The soil was air-dried and sieved through a 5 mm sieve, then layered according to field bulk density. The initial pH of the soil was 9.72, EC was 1.86 mS / cm, and ESP was 31.4%. Nine treatments were established: CK (blank control group), T1 (Example 1 group), T2 (Example 2 group), T3 (Example 3 group), D1 (Comparative Example 1 group), D2 (Comparative Example 2 group), D3 (Comparative Example 3 group), D4 (Comparative Example 4 group), and D5 (Comparative Example 5 group), with each treatment replicated three times. Three simulated irrigations were performed after application, and the leachate was collected and the Na+ content was measured. + and Ca 2+ Concentration. After the experiment, soil samples were taken in layers of 0-10cm and 10-20cm to determine pH, ESP, and exchangeable Na+. + and exchangeability Ca 2+ .

[0213] Na + and Ca 2+ It can be determined using a flame photometer, atomic absorption spectrometry, or ICP-OES. ESP is determined based on exchangeable Na. + Calculation of percentage of cation exchange capacity. Data are expressed as mean ± standard deviation, with n=3 replicates; different lowercase letters in the same column indicate differences at the P < 0.05 level.

[0214] 2. Experimental Results Surface alkalinity reduction effect: In the embodiment of this invention, the soil pH in the 0-10cm layer was significantly lower than that in all comparative groups, indicating that the fast-release component F precisely exerted its alkalinity-reducing effect in the upper layer; the single slow-release component S had a limited decrease in surface soil pH due to the lack of acid release in the upper layer.

[0215] 2. Calcium-sodium exchange depth: In the embodiments of this invention, 10-20 cm of exchangeable Ca²⁺ + The increase was significantly higher than that of the control group, proving that the slow-release calcium source was accurately released in the lower layer, and that the infiltration of the acidic environment in the upper layer promoted the dissolution and infiltration of calcium, thus achieving deep sodium replacement.

[0216] 3. Sodium leaching and infiltration: Example 1 of this invention accumulates Na +The leaching rate increased by 67.6% compared to the existing technology of whole-field application, and the water infiltration time was shortened by 36.5%, proving that the closed-loop mechanism of "sodium desorption in the upper layer + sodium replacement in the lower layer + sodium leaching by water" is valid. At the same time, the soil structure is improved and the infiltration capacity is enhanced.

[0217] Table 3

[0218] Note: Different lowercase letters in the same column indicate significant differences (P < 0.05).

[0219] Example 3: Verification of corn emergence rate, seedling height, taproot length, and surface crust strength in the field. 1. Testing Method A small-plot experiment was conducted in a direct-seeded maize field in moderately to severely saline-alkali dryland. Before sowing, the soil pH (0-20 cm) was 9.63, EC was 1.74 mS / cm, and ESP was 29.8%. Nine treatments were set up: CK (blank control group), T1 (Example 1), T2 (Example 2), T3 (Example 3), D1 (Comparative Example 1), D2 (Comparative Example 2), D3 (Comparative Example 3), D4 (Comparative Example 4), and D5 (Comparative Example 5), with four replicates per treatment. The plot area was 40 m². 2 Randomized block design was used. Emergence rate was assessed on day 7 post-sowing, and seedling height, taproot length, surface crust strength, and soil pH (0-10 cm) were measured on day 21. Surface crust strength was measured using a soil hardness tester or penetration resistance meter; taproot length was measured by randomly sampling 10 plants per plot after root washing; emergence rate was calculated as the percentage of actual seedlings to the theoretical number of seeds sown.

[0220] Data are expressed as mean ± standard deviation, with n=4 replicates; different lowercase letters in the same column indicate differences at the P<0.05 level.

[0221] 2. Experimental Results A single fast-release F increased the germination rate by approximately 15.6%, and a single slow-release S increased the germination rate by approximately 7.7%. The theoretical increase from the linear superposition of the two is approximately 23.3%. However, Example 1 of this invention actually increased the germination rate by approximately 27.8%, which is about 19.3% higher than the theoretical value. Indicators such as taproot length and sodium leaching also showed significant synergistic gains, proving that the combined technical solution of "particle size classification + spatial positioning + window matching" of this invention produces technical effects that cannot be expected by those skilled in the art.

[0222] Compared with conventional whole-field application (Comparative Example 3), Example 1 of the present invention, with an application rate of only 1 / 10 of that, increased the germination rate by about 16.9%, increased the main root length by 42.2%, and reduced the surface crust strength by 34.9%, achieving significant reduction in amount and increase in efficiency.

[0223] Table 4

[0224] Note: Different lowercase letters in the same column indicate significant differences (P < 0.05).

[0225] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A soda-based rhizosphere amendment granule for direct-seeded maize in saline-alkali dryland fields, characterized in that, It includes an immediate-release component F and a sustained-release component S. The immediate-release component F, by mass percentage, includes the following components: Acidic calcium source material 35-55%; Iron salts 3-10%; Fine-grained biochar 10-20%; 2-6% lignin sulfonate; 1-8% organic acids or organic acid salts; Adhesive 1-5%; and Inert mineral filler allowance; The sustained-release component S, by mass percentage, comprises the following components: Calcium source materials: 30-50%; Calcium-based bentonite 10-25%; Humic acid 8-15%; Mesoporous carbon materials: 10-20%; Adhesive 1-4%; and Inert mineral filler allowance.

2. The improved granule according to claim 1, characterized in that, The mass ratio of the rapid-release component F to the sustained-release component S is 1:1.5-3.0; Preferably, the mass ratio of the rapid-release component F to the sustained-release component S is 1:1.8-3.

0.

3. The improved granule according to claim 1, characterized in that, The acidic calcium source material is a calcium-based material that has been impregnated and cured with an organic acid solution; The calcium source material is selected from one or more of phosphogypsum, desulfurized gypsum, natural gypsum, and calcium sulfate; The iron salt is selected from one or more of ferric sulfate, ferrous sulfate, and polyferric sulfate; The organic acid is selected from one or more of citric acid, malic acid, tartaric acid, oxalic acid, acetic acid, lactic acid, and fumaric acid; The organic acid salts are selected from one or more of citrate, malate, tartrate and humate; The adhesive is selected from one or more of starch-based adhesives, lignin-based adhesives, carboxymethyl cellulose, and alginate; The inert mineral filler is selected from one or more of bentonite, zeolite powder, diatomite and attapulgite. The mesoporous carbon material is selected from one or more of mesoporous biochar, activated carbon, bamboo-based porous carbon, straw-based porous carbon, and carbon-based molecular sieves.

4. The improved granule according to claim 3, characterized in that, The organic acid is a compound system composed of citric acid and malic acid in a mass ratio of 2:1; The organic acid salt is calcium citrate.

5. The improved granule according to claim 1, characterized in that, The fine-grained biochar has a particle size of 0.05-0.25 mm and a specific surface area of ​​not less than 80 m². 2 / g; The mesoporous carbon material described above has a pore size of 2-50 nm and a specific surface area of ​​not less than 120 m². 2 / g.

6. The improved granule according to claim 1, characterized in that, The preparation method of the fast-release component F is as follows: after crushing, sieving, and mixing the raw materials evenly, water is added to moisten the mixture, and then the fast-release particles are obtained by extrusion granulation, spheroidization, drying, and sieving. The method for preparing the sustained-release component S is as follows: after crushing, sieving, and mixing the raw materials evenly, water is added to adjust the moisture content, and the sustained-release particles are obtained by extrusion granulation, spheroidization, drying, and sieving.

7. The improved granule according to claim 6, characterized in that, The particle size of the fast-release component F is 0.3-0.8 mm.

8. The improved granule according to claim 6, characterized in that, The particle size of the sustained-release component S is 1.2-2.8 mm.

9. The method of applying the improved granules according to any one of claims 1-8, characterized in that, Includes the following steps: When directing corn in moderately to severely saline-alkali dryland fields, create corn planting furrows and apply the fast-release component F to the planting zone beside and / or above the corn seeds; apply the slow-release component S to the area below and / or to the lateral root extension zone of the corn seeds. After sowing, cover with soil and compact, and manage water according to the conventional cultivation methods for dryland corn.

10. The positioning and application method according to claim 9, characterized in that, The total application rate of the improved granules is 200-400 kg / mu; when the pH of the 0-20cm soil layer is 9.0-9.5 and the ESP is 20%-30%, the total application rate is 200-280 kg / mu; when the pH is 9.5-10.0 and the ESP is 30%-40%, the total application rate is 280-350 kg / mu; when the pH is >10 or the ESP is >40%, the total application rate is 350-400 kg / mu.

Images