Water and fertilizer retaining type artificial planting soil and preparation method thereof

Abstract

The present application relates to a kind of water and fertilizer type artificial planting soil and its preparation method.The method first mixes expanded perlite, vermiculite and zeolite particles to form porous mineral framework, then sprays humic acid potassium moisture liquid to form low-humidity humic acid pre-attached mineral framework;Then, three sections are added by sodium carboxymethyl cellulose, sodium alginate and cross-linked polyacrylate potassium consisting of semi-hydrated cellulose water-retaining adjusting component, and atomized water is formed into semi-hydrated water-retaining mineral framework;Then, calcium magnesium light fixing liquid treatment forms water film fixed mineral framework, and finally, with coconut fiber, humified organic matter, slow-release nutrient component and microbial organic fertilizer are compounded and balanced.The present application is beneficial to improve the water-retaining capacity, dry-wet cycle stability and nutrient retention capacity of artificial planting soil, while maintaining suitable air porosity.

Description

Technical Field

[0001] This invention relates to the technical field of artificial cultivation substrates, and in particular to a water-retaining and fertilizer-retaining artificial planting soil and its preparation method. Background Technology

[0002] Artificial planting soil is a cultivation medium formulated by humans, primarily composed of organic materials, inorganic mineral particles, and nutrient regulators. It is commonly used in protected cultivation, horticultural seedling production, potted flowers, rooftop greening, landscape planting, and soil-alternative planting scenarios. Compared to natural soil, the raw material composition, bulk density, porosity, and nutrient levels of artificial planting soil are easier to control, allowing for the establishment of a relatively stable rhizosphere growth foundation based on different cultivation objects and usage environments.

[0003] Artificial planting soil needs to simultaneously serve multiple functions during use, including plant anchorage, water retention, air exchange, and nutrient supply. Its performance depends not only on the water absorption or fertilizer content of a single component, but also on the porosity between various particles, the way water remains in the substrate, and the migration of soluble nutrients during watering. Under conditions of continuous watering, evaporation, and root absorption, if artificial planting soil cannot maintain appropriate water retention and nutrient buffering capacity, it is prone to problems such as rapid salt release in the early stages, insufficient nutrients in the later stages, or large fluctuations in rhizosphere moisture.

[0004] Currently, to improve the performance of artificial planting soil, organic materials such as coconut coir, peat, and compost are typically added to the substrate to enhance its water-holding capacity. Mineral particles such as perlite, vermiculite, and zeolite are added to adjust porosity and adsorption capacity. Water-absorbing resins, humic acids, organic fertilizers, or slow-release fertilizers are also used to improve water retention and nutrient supply. These measures can improve the overall performance of artificial planting soil to some extent. However, because different components act differently in the processes of water absorption, expansion, adsorption, and release, it is still difficult to balance water retention, aeration, and nutrient retention in practical applications.

[0005] Especially under conditions of repeated watering and alternating wet and dry periods, the migration of water in the substrate also carries away some soluble nutrients. If the substrate's ability to retain water is insufficient, the problem of nutrient loss with water will be more pronounced; simply increasing the proportion of water-absorbing components may cause excessive water absorption and swelling in localized areas, affecting interparticle porosity and rhizosphere air exchange, and resulting in uneven nutrient release in localized areas. Therefore, there is still a need to further improve the stability of water and nutrient retention in artificial planting soils during long-term use.

[0006] Therefore, artificial planting soil still needs to form a more stable matching relationship between water retention, nutrient buffering and rhizosphere suitability during long-term use, in order to adapt to the cultivation environment of frequent watering, obvious wet-drying and wet-drying, and continuous nutrient absorption by plants. Summary of the Invention

[0007] This invention provides a water-retaining and fertilizer-retaining artificial planting soil and its preparation method. By controlling the compounding and preparation process of porous mineral skeleton, organic matrix, water-retaining regulating components and nutrient components, the artificial planting soil can maintain good water retention capacity and nutrient buffering capacity under watering and alternating wet and dry conditions.

[0008] To achieve the above objectives, the first aspect of the present invention provides a method for preparing water-retaining and fertilizer-retaining artificial planting soil, comprising the following steps: S1: Mix expanded perlite, vermiculite and zeolite particles to obtain a porous mineral framework; S2: Apply potassium humate conditioning solution to the porous mineral framework to make the water content of the porous mineral framework reach 10% to 18%, and after mixing, a low-moisture humic acid pre-attached mineral framework is obtained. S3: The hemihydrated cellulose water-retaining and regulating component is added to the low-moisture humic acid pre-attached mineral skeleton in several batches, and water is added by atomization during the addition process, so that the moisture content of the material increases from 10% to 18% to 18% to 26%, and a hemihydrated water-retaining mineral skeleton is obtained. S4: The calcium-magnesium light fixation solution is sprayed into the semi-hydrated water-retaining mineral skeleton so that the moisture content of the material reaches 22% to 30%, and the water film fixed mineral skeleton is obtained after mixing. S5: Mix the water-film-fixed mineral skeleton with coconut coir fiber and decomposed organic matter to obtain a water-retaining planting soil substrate; S6: Add the slow-release nutrient group and microbial organic fertilizer to the water-retaining planting soil substrate, mix and adjust the final moisture content to 26% to 36%, and let it stand at 15 to 30℃ for 18 to 48 hours to obtain water-retaining and fertilizer-retaining artificial planting soil. The hemihydrated cellulose water-retaining and regulating components include sodium carboxymethyl cellulose, sodium alginate, and cross-linked potassium polyacrylate.

[0009] Through the above steps, expanded perlite, vermiculite, and zeolite particles first form a porous mineral framework with supporting pores and adsorption sites. This allows subsequent water, potassium humate, and water-retaining components to preferentially act on the surface of the mineral particles, rather than being directly absorbed in large quantities by the coconut fiber and decomposed organic matter. In this way, the active areas in the artificial planting soil that play a role in water and fertilizer retention are first established on the mineral framework. When subsequently combined with the organic matrix, the overall structure will be more uniform and easier to maintain its looseness.

[0010] In step S2, a potassium humate conditioning solution is sprayed onto the porous mineral framework, with the moisture content controlled at 10%–18%. This allows the potassium humate to adhere to the surface and pores of the expanded perlite, vermiculite, and zeolite particles under relatively low humidity. The moisture at this stage is not intended to fully wet the system, but rather to provide a relatively stable landing point for the potassium humate. The pre-distribution of potassium humate on the mineral framework surface provides a wetting basis and adsorption environment for the subsequent hemihydrated cellulose water-retaining conditioning components, making it easier for these components to form a thin layer on the mineral particle surface.

[0011] In step S3, the hemihydrated cellulose water-retaining and regulating component gradually enters the low-moisture humic acid pre-attached mineral framework under atomized water replenishment conditions, increasing the material's moisture content from 10%–18% to 18%–26%. Within this moisture content range, sodium carboxymethyl cellulose and sodium alginate can form a relatively continuous moist thin layer, while cross-linked potassium polyacrylate is in a partially water-absorbing state and does not directly transform into obvious gel clusters. The advantage of this process is that the water-retaining component does not simply remain in the system waiting to absorb water, but rather forms a moderately hydrated water-containing layer on the surface of the mineral particles, laying the foundation for subsequent moisture retention and nutrient buffering.

[0012] In step S4, after the calcium-magnesium light fixation solution enters the hemihydrated water-retaining mineral framework, calcium and magnesium ions can form slight bonds with the oxygen-containing functional groups in sodium carboxymethyl cellulose, sodium alginate, and potassium humate, stabilizing the already formed hemihydrated water-retaining thin layer. Since the calcium-magnesium light fixation solution is added after the hemihydrated water-retaining mineral framework has formed, its effect is primarily focused on the already spread water film area, rather than causing localized hardening or concentrated flocculation in the system. This allows the water film-fixed mineral framework to maintain its water-holding capacity while continuing to preserve the interparticle air-permeable pores.

[0013] In step S5, the water film fixes the mineral framework, which is then mixed with coconut coir fiber and decomposed organic matter. This allows the mineral framework to provide structural support and local water and fertilizer retention, while the coconut coir fiber and decomposed organic matter provide flexible water retention, root contact, and organic matter supply. After the two types of substrates are combined at this stage, the artificial planting soil has both good water buffering capacity and loose space suitable for root expansion.

[0014] In step S6, the slow-release nutrient components and microbial organic fertilizer are added after the formation of the water-film-fixed mineral framework, and then allowed to stand and equilibrate for 18–48 hours at a moisture content of 26%–36%. This allows the soluble nutrients on the surface of the slow-release nutrient components to come into contact with the water-film-fixed mineral framework first. The water-containing thin layer in the water-film-fixed mineral framework can temporarily retain the initially released soluble salts, while zeolite particles and potassium humate further adsorb and buffer ammonium nitrogen, potassium ions, and some nutrient ions. Through this post-contact and equilibration process, the initial electrical conductivity release of the artificial planting soil is more stable, and the tendency for nutrient loss during watering can be controlled.

[0015] Preferably, based on 100 parts of the dry weight of the water-retaining and fertilizer-retaining artificial planting soil, the expanded perlite comprises 8-18 parts, the vermiculite comprises 5-14 parts, the zeolite particles comprises 5-13 parts, the coconut coir fiber comprises 25-40 parts, the decomposed organic matter comprises 15-28 parts, the potassium humate comprises 1.0-4.0 parts, the hemihydrated cellulose water-retaining and regulating component comprises 0.6-2.2 parts, the calcium and magnesium fixing component comprises 0.4-2.0 parts, wherein a portion of the calcium and magnesium fixing component is used to prepare a calcium and magnesium light fixation solution, the slow-release nutrient group comprises 2.5-7.0 parts, and the microbial organic fertilizer comprises 3-10 parts.

[0016] The above formulation achieves a relatively balanced quality relationship among the mineral framework, organic matrix, water-retaining and regulating components, and nutrient components. The amount of expanded perlite, vermiculite, and zeolite particles provides sufficient particle support and adsorption space; the amount of coconut coir fiber and decomposed organic matter ensures a suitable root contact environment and organic matter base; the amount of hemihydrated cellulose water-retaining and regulating components is at a low level, forming a water-bearing thin layer without excessively occupying pores; the amount of calcium and magnesium fixation components provides mild stabilization to the water-bearing thin layer; and the amount of slow-release nutrient components and microbial organic fertilizer meets the nutrient requirements of plants in the early and continuous growth stages. Overall, this formulation achieves a relatively harmonious balance between water retention, aeration, nutrient buffering, and matrix stability.

[0017] Preferably, in step S1, the mass ratio of the expanded perlite, the vermiculite, and the zeolite particles is 100:35-75:30-70; the particle size of the expanded perlite is 1-4 mm, the particle size of the vermiculite is 0.5-3 mm, and the particle size of the zeolite particles is 0.3-2 mm.

[0018] By limiting the proportions and particle sizes of expanded perlite, vermiculite, and zeolite, a porous mineral framework can simultaneously perform three functions: macroporous support, layered water retention, and ion adsorption. Expanded perlite, with its larger particle size, primarily maintains the aeration pores between particles; vermiculite has good interlayer water retention capacity, improving water buffering; and zeolite, with its smaller particle size and ion exchange capacity, participates in nutrient retention. When these three are mixed in this proportion, water and nutrients are not confined to a single material but rather form a distribution gradient among mineral particles of different sizes and adsorption capacities, which is beneficial for improving the structural stability and water and fertilizer retention capacity of artificial planting soil.

[0019] Preferably, in step S1, the zeolite particles are clinoptilolite particles, and the cation exchange capacity of the clinoptilolite particles is 80-160 cmol / kg; in step S2, the mass concentration of potassium humate in the potassium humate conditioning solution is 1.0%-4.0%, and the pH is 7.5-9.0.

[0020] Clinoptilolite particles possess relatively stable cation exchange capacity. When the cation exchange capacity is controlled within 80–160 cmol / kg, it can provide suitable exchange and adsorption space for ammonium nitrogen, potassium ions, and some medium-level elements. Maintaining the concentration and pH of the potassium humate conditioning solution within this range ensures good dispersion of potassium humate and allows it to adhere evenly to the surface of the mineral particles during spraying. At a pH of 7.5–9.0, the carboxyl and phenolic hydroxyl groups in potassium humate more readily exhibit complexing and adsorption capabilities, subsequently forming a more stable water film base when combined with calcium and magnesium ions and cellulose-based water-retaining and regulating components.

[0021] Preferably, in step S3, the mass ratio of sodium carboxymethyl cellulose, sodium alginate, and crosslinked potassium polyacrylate is 100:15-45:20-70.

[0022] At this ratio, sodium carboxymethyl cellulose, as the main film-forming and thickening component, can form a continuous, moistened thin layer on the surface of mineral particles; sodium alginate, as a component that can slightly bind with calcium and magnesium ions, can enhance subsequent fixation stability; and cross-linked potassium polyacrylate, as a water-absorbing component, can improve the water-holding capacity of the water-containing thin layer. After the ratio of the three components is controlled as described above, the water-regulating component tends to form a semi-hydrated thin layer, rather than simply relying on the free expansion of the superabsorbent resin to increase water holding capacity. This allows the artificial planting soil to maintain good interparticle porosity while improving its water holding capacity.

[0023] Preferably, in step S3, the hemihydrated cellulose water-retaining and regulating component is added to the low-moisture humic acid pre-attached mineral skeleton in three stages, and atomized water replenishment is performed during the three stages of addition. The first stage involves adding 30%–45% of the total mass of the hemihydrated cellulose water-retaining and regulating components, and adding 25%–38% of the total mass of atomized water replenishment. Mix for 3–6 minutes to obtain the first stage of hemihydrated mineral skeleton. In the second stage, 35% to 50% of the total mass of the hemihydrated cellulose water-retaining and regulating components are added, along with 35% to 48% of the total mass of atomized water replenishment. The mixture is then stirred for 4 to 8 minutes to obtain the second-stage hemihydrated mineral skeleton. In the third stage, 15% to 30% of the total mass of the hemihydrated cellulose water-retaining and regulating components are added, along with 18% to 32% of the total mass of atomized water replenishment. The mixture is then stirred for 6 to 12 minutes to obtain the hemihydrated water-retaining mineral skeleton.

[0024] The three-stage addition and three-stage atomized water replenishment transform the hydration process of the hemihydrated cellulose water-retaining and regulating components from a one-time water absorption and expansion to a gradual progression along the path of initiation of adhesion, continuous expansion, and convergence homogenization. In the first stage, a portion of the hemihydrated cellulose water-retaining and regulating components and a portion of the atomized water initially contact the low-moisture humic acid pre-attached mineral framework, causing sodium carboxymethyl cellulose and sodium alginate to initially wet and adhere to the surface of the mineral particles already attached to potassium humate, while cross-linked potassium polyacrylate is only in a preliminary water-absorbing state. The purpose of this stage is not to pursue maximum water absorption, but to allow the water-retaining and regulating components to first obtain a stable surface attachment position.

[0025] In the second stage, the proportion of water-retaining conditioning components and atomized water is relatively increased, allowing the initial moistened area formed in the first stage to continue spreading to the surface of mineral particles, pore areas, and particle contact points. This stage transforms the semi-hydrated region from a point-like or locally attached state to a more continuous thin layer, providing an accessible water film basis for the subsequent uniform action of calcium and magnesium ions. Since water still enters via atomization and the material moisture content is controlled within 18%–26%, the hydration process of the water-retaining conditioning components is jointly restricted by the mineral skeleton surface and the potassium humate adhesion layer, making it difficult to form a large-volume free gel.

[0026] In the third stage, the amount of water-retaining conditioning components and atomized water added is relatively reduced, while the mixing time is extended, causing the semi-hydrated region to shift from continued rapid water absorption to homogenization and convergence. The focus of this stage is to refine the water-bearing thin layer formed in the first two stages, making its distribution on the surface of mineral particles more stable, rather than continuing to increase the degree of local water absorption and swelling. Through this subsequent convergence treatment, the water absorption of cross-linked potassium polyacrylate is confined within the semi-hydrated thin layer, while sodium carboxymethyl cellulose and sodium alginate play a role in continuous water film and subsequent ion fixation and reception.

[0027] Therefore, the three-stage addition and three-stage atomized water replenishment in step S3 are not simple batch mixing, but rather involve phased changes in the water supply, the amount of water-retaining conditioning component added, and the mixing time, causing the water-retaining conditioning component to undergo three processes: surface initiation, thin-layer expansion, and incremental convergence. In the resulting semi-hydrated water-retaining mineral framework, the water-retaining conditioning component tends to be distributed as a water-containing thin layer on the surface of mineral particles and in the contact areas between particles, rather than forming localized gel clusters. This state provides a more stable and dispersed target for calcium and magnesium light fixation in step S4, allowing calcium and magnesium ions to primarily fix the already spread semi-hydrated thin layer without easily inducing localized gelation or pore blockage.

[0028] Preferably, the water holding increment in step S3 satisfies the following relationship: Wherein, W0 is the water-holding mass of the low-moisture humic acid pre-attached mineral skeleton after saturation water absorption and free drainage for 30 minutes, measured by sampling before step S3, in kg; W1 is the water-holding mass of the first-stage semi-hydrated mineral skeleton after saturation water absorption and free drainage for 30 minutes, in kg; W2 is the water-holding mass of the second-stage semi-hydrated mineral skeleton after saturation water absorption and free drainage for 30 minutes, in kg; and W3 is the water-holding mass of the semi-hydrated water-retaining mineral skeleton after saturation water absorption and free drainage for 30 minutes, in kg.

[0029] The aforementioned water-holding increment relationship is used to define the formation path of the semi-hydrated water film in step S3, rather than simply defining the final water-holding capacity. W1-W0 reflects the initial water-holding increment generated relative to the low-moisture humic acid pre-attached mineral framework after the first stage of addition. This increment corresponds to the degree of initial adhesion of the water-retaining regulating component on the surface of the mineral particles. W2-W1 reflects the continued water-holding increment generated after the second stage of addition. This increment corresponds to the extent of expansion of the semi-hydrated water film on the surface of the mineral particles and in the contact area between the particles. W3-W2 reflects the final water-holding increment generated after the third stage of addition. This increment corresponds to the change in the newly added water-holding capacity during the subsequent hydration and homogenization processes.

[0030] The first relationship, achieved by squared-up water-holding increment in the second stage and comparing it with the product of water-holding increments in the first and third stages, simultaneously constrains the relative relationships between the three hydration stages. A value between 1.1 and 3.2 indicates that the water-holding increment in the second stage has sufficient continuity relative to the initial increment in the first stage, while also exhibiting a moderate advantage relative to the final increment in the third stage. This suggests that the main water film expansion in step S3 occurs in the second stage, while the third stage has gradually transitioned from continued expansion to convergence and homogenization. This relationship avoids two unfavorable conditions: first, insufficient hydration in the first and second stages leading to discontinuous semi-hydrated thin layers; second, the third stage maintaining a strong increment, causing the water-retaining regulating component to continuously absorb water and expand, resulting in a tendency for localized gelation.

[0031] The second relationship limits the overall water-holding change rate of W3 relative to W0 to 0.18–0.65, ensuring that the hemihydrated water-retaining mineral skeleton after step S3 has both the necessary water-holding capacity enhancement and avoids excessive overall water absorption. Insufficient overall water-holding change indicates that the hemihydrated cellulose water-retaining regulating component has not fully participated in water film formation, resulting in a lack of stable substrates for subsequent calcium and magnesium fixation. Excessive overall water-holding change indicates that the water-retaining regulating component has shifted from a hemihydrated thin-layer state to a free-expanding state, easily occupying the air-permeable pores between mineral particles. Limiting this overall change rate within the above range ensures that the final state of step S3 remains within the moderate hemihydrated range.

[0032] Through the two relationships mentioned above, step S3 forms a semi-hydrated water-retaining mineral framework with process characteristics. Its water-holding capacity does not increase suddenly at a certain stage, nor does it continue to expand disorderly in the later stages, but rather it is gradually established in the order of initiation, expansion, and convergence. This process gives the hydrous thin layer formed by sodium carboxymethyl cellulose and sodium alginate good continuity and fixability, confining the high water absorption of cross-linked potassium polyacrylate to the surface thin layer of the mineral framework. Thus, when the calcium-magnesium light fixation solution enters in step S4, it can mainly undergo slight ionic bonding with the already converged hydrous thin layer, stabilizing the thin layer on the surface of the mineral particles and near the pores, rather than causing the water-retaining conditioning components to continue to concentrate and gel.

[0033] Furthermore, the water film fixation zone formed through the above-mentioned path serves as a receiver for the slow-release nutrients in step S6. When the slow-release nutrients are added and allowed to settle and equilibrate, the soluble nutrients initially released from their surface first enter the water film fixation zone, and are then regulated by the ion exchange of zeolite particles and the complexation and adsorption of potassium humate. As a result, the water retention zone and nutrient buffer zone in the artificial planting soil have a high degree of spatial overlap, making the initial extract conductivity more stable, and the release of nutrients such as nitrogen and potassium during watering more moderate, while still preserving the aeration pores formed by expanded perlite, vermiculite, and zeolite particles. This effect stems from the continuous coordination between the phased water retention increment relationship in step S3, the light fixation of calcium and magnesium in step S4, and the post-nutrient equilibration in step S6.

[0034] Preferably, in step S4, the calcium-magnesium light fixative is prepared from calcium lactate, magnesium sulfate, and water, with a mass ratio of calcium lactate to magnesium sulfate of 100:20-80, and the total concentration of calcium and magnesium ions in the calcium-magnesium light fixative is 0.03-0.18 mol / L. The calcium-magnesium light fixative is sprayed into the semi-hydrated water-retaining mineral framework by atomization for 6-18 minutes, with a mixing speed of 25-50 r / min during spraying, and mixing continues for 10-25 minutes after spraying.

[0035] A calcium-magnesium light fixation solution prepared with calcium lactate and magnesium sulfate provides a mild source of calcium and magnesium ions. Calcium ions facilitate the formation of relatively stable binding sites with sodium alginate and potassium humate, while magnesium ions contribute to ion bridging and nutrient buffering in the water film region. Maintaining the total concentration of calcium and magnesium ions within the range of 0.03–0.18 mol / L keeps the fixation effect within a mild range, enhancing the stability of the semi-hydrated hydrophobic layer without significantly increasing the system's salt burden. Atomized spraying and continuous mixing ensure uniform entry of calcium and magnesium ions into the semi-hydrated water-retaining mineral framework, reducing localized excessive concentrations and making it easier to balance the stability and porosity retention of the water film-fixed mineral framework.

[0036] Preferably, in step S5, the moisture content of the coconut coir fiber before mixing is 12% to 22%, and the moisture content of the decomposed organic matter before mixing is 18% to 32%; in step S6, the slow-release nutrient group comprises coated compound fertilizer, ammonium humate, and potassium magnesium sulfate.

[0037] The moisture content of coconut coir fiber and decomposed organic matter is controlled separately before mixing to prevent significant water competition and agglomeration due to excessive moisture when mixed with the water-film-fixed mineral framework. Coconut coir fiber exhibits good flexibility and dispersibility at a moisture content of 12%–22%, while decomposed organic matter at a moisture content of 18%–32% can be well embedded between mineral particles, forming a suitable substrate environment for root contact. The slow-release nutrient components consist of coated compound fertilizer, ammonium humate, and potassium magnesium sulfate, which can simultaneously provide basic nitrogen, phosphorus, and potassium, organic buffered nitrogen sources, and potassium and magnesium elements. These nutrient components are added after the water-film-fixed mineral framework has formed, allowing for initial release buffering and subsequent fertilization transition through a period of static moisture equilibration.

[0038] The second aspect of the present invention provides a water-retaining and fertilizer-retaining artificial planting soil prepared by the preparation method described above, wherein the saturated water holding capacity of the water-retaining and fertilizer-retaining artificial planting soil is 85% to 150% of its own dry basis mass, the saturated water holding capacity retention rate is not less than 82% after 10 dry-wet cycles, the aeration porosity is 18% to 32%, and the initial extract conductivity is 0.6 to 1.6 mS / cm.

[0039] In the water-retaining and fertilizer-retaining artificial planting soil prepared by the above method, a relatively stable composite relationship is formed among the mineral framework, organic matrix, semi-hydrated water-retaining and regulating components, and nutrient components. The saturated water holding capacity reaches 85%–150% of its dry weight, indicating that the artificial planting soil has good water absorption and retention capacity. After 10 wet-dry cycles, the saturated water holding capacity retention rate is not less than 82%, indicating that the semi-hydrated water film has good cycle stability after calcium and magnesium fixation. The aeration porosity remains at 18%–32%, indicating that the improvement in water retention capacity has not caused the interparticle gas channels to lose their proper function. The initial extract conductivity is 0.6–1.6 mS / cm, indicating that the nutrient components are in a relatively stable state during the initial release stage, which is conducive to seed germination and seedling root growth. Overall, this artificial planting soil achieves a good comprehensive fit between water retention, aeration environment, and nutrient buffering.

[0040] The present invention, by adopting the above technical solution, has the following beneficial effects: 1. This invention first constructs a porous mineral framework and then pre-attaches low-moisture humic acid, allowing water- and fertilizer-retaining sites in the artificial planting soil to preferentially establish themselves on the surfaces of expanded perlite, vermiculite, and zeolite particles. Expanded perlite provides interparticle support pores, vermiculite provides interlayer water-holding space, and zeolite particles provide ion exchange sites. Potassium humate, pre-attached to the surface and pore areas of the mineral particles at a moisture content of 10%–18%, provides a more stable wetting foundation and adsorption environment for subsequent hemihydrated cellulose water-regulating components. Therefore, the water-retaining and nutrient-buffering zones in the artificial planting soil no longer solely rely on the organic matrix for water absorption, but rather form a more stable spatial distribution based on the mineral framework, which is beneficial for improving the stability of the matrix structure and the water and fertilizer retention base.

[0041] 2. This invention employs a three-stage process of adding hemihydrated cellulose water-retaining and regulating components and a three-stage atomized water replenishment, while limiting the water-holding increment relationship in step S3. This allows the water-retaining and regulating components to form a hemihydrated water-bearing thin layer following a path of initiation, expansion, and convergence. This process enables sodium carboxymethyl cellulose and sodium alginate to form a relatively continuous moist thin layer on the surface of mineral particles, confining the water absorption and swelling of cross-linked potassium polyacrylate within the thin layer and reducing the formation of local gel clusters. Further, a calcium-magnesium light fixation solution is used to lightly fix this hemihydrated water-bearing thin layer, enhancing the stability of the water film fixing the mineral skeleton while preserving the aeration pores between particles. This results in artificial planting soil possessing both high saturated water holding capacity, good water retention rate after wet-dry cycles, and suitable aeration porosity.

[0042] 3. In this invention, the slow-release nutrient components and microbial organic fertilizer are added after the formation of the water-film-fixed mineral framework, and then allowed to stand at a moisture content of 26%–36% for 18–48 hours to allow the water-retaining structure to further participate in buffering the initial nutrient release. The soluble nutrients initially released from the surface of the slow-release nutrient components first enter the water-film-fixed area, and are then regulated by the ion exchange of zeolite particles and the complexation and adsorption of potassium humate. This maintains the initial conductivity of the extract in the artificial planting soil within a relatively stable range and reduces the tendency for rapid nutrient migration during watering. Therefore, the artificial planting soil achieves a good overall balance between water retention, aeration, fertilizer retention, and root growth safety. Detailed Implementation

[0043] The specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0044] Unless otherwise defined, all scientific and technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art.

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0047] The present invention will now be described in detail with reference to specific embodiments, which are intended to understand rather than limit the invention.

[0048] Example 1 This embodiment discloses a water-retaining and fertilizer-retaining artificial planting soil and its preparation method. The artificial planting soil, based on a dry weight of 100 kg, comprises the following raw materials: Expanded perlite 12kg, vermiculite 8kg, zeolite granules 8kg, coconut coir fiber 32kg, decomposed organic matter 22kg, potassium humate 2.4kg, hemihydrated cellulose water-retaining and regulating component 1.4kg, calcium and magnesium fixing component 1kg, slow-release nutrient component 4.8kg, microbial organic fertilizer 8.4kg.

[0049] The expanded perlite is horticultural expanded perlite with a particle size of 2–3.5 mm and a bulk density of 95 kg / m³; the vermiculite is horticultural expanded vermiculite with a particle size of 1–2.5 mm; and the zeolite particles are clinoptilolite particles with a particle size of 0.5–1.5 mm and a cation exchange capacity of 120 cmol / kg. The mass ratio of expanded perlite, vermiculite, and zeolite particles is 100:66.7:66.7.

[0050] The coconut coir fiber is desalinated coconut coir fiber with a fiber length of 2-6 mm and a moisture content of 16%. Its conductivity, measured with a 1:5 water extract, is 0.78 mS / cm. The composted organic matter is composted garden waste with a moisture content of 24%, an organic matter content of 48%, and a pH of 7.2. It is used after passing through a 5 mm sieve. The amounts of coconut coir fiber and composted organic matter added are calculated on a dry basis.

[0051] The potassium humate is agricultural grade potassium humate, with an organic matter content of 65%, a humic acid content of 50%, and a moisture content of 10%, calculated on a dry basis. The total amount of potassium humate is 2.4 kg, of which 0.15 kg is used in step S2 to prepare the potassium humate conditioning solution, and the remaining 2.25 kg is used in step S5 to mix with the organic matrix.

[0052] The hemihydrated cellulose water-retaining agent consists of sodium carboxymethyl cellulose, sodium alginate, and cross-linked potassium polyacrylate in a mass ratio of 100:30:45. Based on a total mass of 1.4 kg of the hemihydrated cellulose water-retaining agent, sodium carboxymethyl cellulose comprises 0.8 kg, sodium alginate 0.24 kg, and cross-linked potassium polyacrylate 0.36 kg. A 1% aqueous solution of sodium carboxymethyl cellulose has a viscosity of 800 mPa·s and a degree of substitution of 0.75; a 1% aqueous solution of sodium alginate has a viscosity of 350 mPa·s; and cross-linked potassium polyacrylate is an agricultural granular water-retaining agent with a particle size of 0.18–0.85 mm.

[0053] The calcium-magnesium fixative consists of calcium lactate and magnesium sulfate in a mass ratio of 100:50. Based on a total mass of 1 kg of the calcium-magnesium fixative, calcium lactate comprises 0.667 kg and magnesium sulfate comprises 0.333 kg. Of the total calcium-magnesium fixative, 0.09 kg is used in step S4 to prepare the calcium-magnesium light fixative solution, and the remaining 0.91 kg is added together with the slow-release nutrient components in step S6. Calcium lactate is calculated using anhydrous calcium lactate, and magnesium sulfate is calculated using anhydrous magnesium sulfate.

[0054] The slow-release nutrient group consists of coated compound fertilizer, ammonium humate, and potassium magnesium sulfate, in a mass ratio of 100:25:35. Based on a total slow-release nutrient group mass of 4.8 kg, the coated compound fertilizer comprises 3 kg, ammonium humate 0.75 kg, and potassium magnesium sulfate 1.05 kg. The coated compound fertilizer contains 15% nitrogen, 15% phosphorus pentoxide, and 15% potassium oxide by mass, with a nutrient release period of 60 days. The microbial organic fertilizer is a fully decomposed granular microbial organic fertilizer with an organic matter content of 45% and an effective viable bacteria count of 2.0 × 10⁻⁶. 8 CFU / g, with a particle size of 1-3 mm and a moisture content of 20%, the amount added is calculated based on dry weight.

[0055] The preparation method of this embodiment is as follows.

[0056] S1: Add 12 kg of expanded perlite, 8 kg of vermiculite and 8 kg of zeolite particles to a horizontal paddle mixer and mix for 8 min at 45 r / min to obtain a porous mineral skeleton.

[0057] During the mixing process, water was not sprayed into the materials, and no coconut coir fiber or decomposed organic matter was added, allowing the expanded perlite, vermiculite, and zeolite particles to first form a particle support system. After this step, the initial moisture content of the porous mineral framework was measured to be 3.6%.

[0058] S2: Take 0.15 kg of potassium humate and add it to 3.6 kg of water. Stir at room temperature for 20 min to obtain a potassium humate conditioning solution. The mass concentration of potassium humate in this potassium humate conditioning solution is 4%, and the pH is 8.3.

[0059] The potassium humate conditioning solution was completely added to the porous mineral framework obtained in step S1 via atomized spraying. During the spraying process, the mixer speed was 45 r / min, and the spraying time was 12 min. After spraying, mixing continued for 10 min to bring the moisture content of the porous mineral framework to 14.2%, resulting in a low-moisture humic acid pre-attached mineral framework.

[0060] In this step, 0.15 kg of potassium humate is used to form a low-moisture pre-adhesion layer on the surface of expanded perlite, vermiculite, and zeolite particles; the remaining potassium humate is not added in this step.

[0061] S3: Dry mix 0.8 kg of sodium carboxymethyl cellulose, 0.24 kg of sodium alginate and 0.36 kg of crosslinked potassium polyacrylate for 5 min to obtain 1.4 kg of hemihydrated cellulose water-retaining and regulating component.

[0062] The hemihydrated cellulose water-retaining and regulating component was added in three stages to the low-moisture humic acid pre-attached mineral framework obtained in step S2, and atomized water replenishment was performed during each of the three stages of addition. The total mass of atomized water replenishment was 5 kg.

[0063] In the first stage, 0.56 kg of hemihydrated cellulose water-retaining and regulating component was added, accounting for 40% of the total mass of the hemihydrated cellulose water-retaining and regulating component; at the same time, 1.6 kg of atomized water was added, accounting for 32% of the total mass of atomized water. After addition, the mixture was mixed at 45 r / min for 5 min to obtain the first stage of hemihydrated mineral skeleton.

[0064] In the second stage, 0.6 kg of hemihydrated cellulose water-retaining and regulating component was added, accounting for 42.9% of the total mass of the hemihydrated cellulose water-retaining and regulating component; at the same time, 2.1 kg of atomized water was added, accounting for 42% of the total mass of atomized water. After addition, the mixture was mixed at 45 r / min for 6 min to obtain the second-stage hemihydrated mineral skeleton.

[0065] In the third stage, 0.24 kg of hemihydrated cellulose water-retaining and regulating component was added, accounting for 17.1% of the total mass of the hemihydrated cellulose water-retaining and regulating component; at the same time, 1.3 kg of atomized water was added, accounting for 26% of the total mass of atomized water. After addition, the mixture was mixed at 40 r / min for 10 min to obtain a hemihydrated water-retaining mineral skeleton.

[0066] After step S3 was completed, the moisture content of the material was measured to be 24.6%.

[0067] To characterize the hemihydrate formation process in step S3, 1 kg samples were taken before the start of step S3, after the completion of the first stage, after the completion of the second stage, and after the completion of the third stage. The water-holding capacity was determined using the same method. The specific determination method was as follows: the sample was placed in a nylon mesh bag and immersed in clean water for 30 min to allow the sample to reach a saturated water absorption state. After removal, the sample was allowed to drain freely at room temperature for 30 min. The mass of the sample after free drainage was weighed, and the mass of the nylon mesh bag was subtracted to obtain the water-holding capacity.

[0068] The measured values ​​were: W0 = 1.46 kg, W1 = 1.72 kg, W2 = 2.03 kg, and W3 = 2.29 kg.

[0069] Therefore, we can conclude that: (W2-W1) 2 / [(W1-W0)(W3-W2)]=1.42; (W3-W0) / W0=0.568.

[0070] S4: Take 0.09 kg of the calcium-magnesium fixative component to prepare a calcium-magnesium light fixative solution, which contains 0.06 kg of calcium lactate and 0.03 kg of magnesium sulfate. Add 0.06 kg of calcium lactate and 0.03 kg of magnesium sulfate to 3 kg of water and stir for 15 min to obtain the calcium-magnesium light fixative solution. The total concentration of calcium and magnesium ions in this calcium-magnesium light fixative solution is 0.175 mol / L.

[0071] The calcium-magnesium light fixation solution was sprayed onto the semi-hydrated water-retaining mineral framework obtained in step S3 using an atomized method. The spraying time was 12 minutes, and the mixing speed during the spraying process was 35 r / min. After spraying, mixing continued for 18 minutes to ensure that the calcium-magnesium ions were fully in contact with the sodium carboxymethyl cellulose, sodium alginate, and potassium humate in the semi-hydrated water-retaining mineral framework, thus obtaining a water-film fixed mineral framework.

[0072] After step S4 was completed, the moisture content of the material was measured to be 29.9%.

[0073] In this step, only 0.09 kg of the calcium-magnesium fixation component is added to the calcium-magnesium light fixation solution to complete the light fixation of the semi-hydrated aqueous thin film; the remaining 0.91 kg of the calcium-magnesium fixation component is not added in this step.

[0074] S5: Weigh the coconut coir fiber based on a dry basis of 32 kg, with an actual moisture content of 16% at the time of weighing; weigh the decomposed organic matter based on a dry basis of 22 kg, with an actual moisture content of 24% at the time of weighing.

[0075] Take 2.25 kg of potassium humate (not added in step S2), and add it together with coconut coir fiber and decomposed organic matter into another mixer. Mix at 35 r / min for 8 min to obtain an organic matrix containing potassium humate. Then add the organic matrix containing potassium humate to the water-film-fixed mineral framework obtained in step S4, and mix at 35 r / min for 15 min to obtain a water-retaining planting soil substrate.

[0076] In this step, the remaining potassium humate is added to the organic substrate by dry mixing, which on the one hand replenishes the total amount of potassium humate in the artificial planting soil, and on the other hand avoids introducing too much water in step S2 due to the low-moisture pre-attachment requirement.

[0077] S6: Add 3 kg of coated compound fertilizer, 0.75 kg of ammonium humate, 1.05 kg of potassium magnesium sulfate, 8.4 kg of microbial organic fertilizer, and 0.91 kg of calcium magnesium fixation component not added in step S4 to the water-retaining planting soil substrate obtained in step S5, and mix for 10 min at 30 r / min to obtain nutrient-containing artificial planting soil.

[0078] Water was added to the nutrient-rich artificial planting soil via atomization until the final moisture content reached 31%. The material was then placed in a polypropylene turnover box with ventilation holes, with a layer thickness of 18cm, and allowed to stand at 25℃ for 30 hours to achieve equilibrium, resulting in a water-retaining and fertilizer-retaining artificial planting soil.

[0079] During the static balancing process, the feed is turned over once every 10 hours, with each turning lasting 3 minutes, to ensure full contact between the water film fixing the mineral skeleton, the slow-release nutrient components, the calcium and magnesium fixing components, and the organic matrix, while avoiding local water accumulation.

[0080] The water-retaining and fertilizer-retaining artificial planting soil prepared in this embodiment is a loose granular mixed substrate. It can be formed into a clump by hand and then easily crumbled upon light touch. No continuous gel clumps with a diameter greater than 5 mm were observed. It can be subsequently used as a seedling substrate, potting substrate, or greenhouse cultivation substrate.

[0081] Example 2 This embodiment discloses a water-retaining and fertilizer-retaining artificial planting soil and its preparation method. The difference from Embodiment 1 is that this embodiment uses a lower amount of water-retaining regulating component and a lower calcium and magnesium fixation strength.

[0082] In this embodiment, based on 100 kg of dry artificial planting soil, the following raw materials are included: Expanded perlite 14kg, vermiculite 6kg, zeolite granules 7kg, coconut coir fiber 35kg, decomposed organic matter 23kg, potassium humate 1.5kg, hemihydrated cellulose water-retaining and regulating component 0.8kg, calcium and magnesium fixing component 0.5kg, slow-release nutrient component 3.5kg, microbial organic fertilizer 8.7kg.

[0083] The mass ratio of expanded perlite, vermiculite, and zeolite particles is 100:42.9:50.

[0084] The hemihydrated cellulose water-retaining and regulating component consists of sodium carboxymethyl cellulose, sodium alginate, and cross-linked potassium polyacrylate in a mass ratio of 100:20:35. Based on a total mass of 0.8 kg for the hemihydrated cellulose water-retaining and regulating component, sodium carboxymethyl cellulose comprises 0.516 kg, sodium alginate 0.103 kg, and cross-linked potassium polyacrylate 0.181 kg.

[0085] In step S2, 0.12 kg of potassium humate is added to 2.88 kg of water to prepare a 4% potassium humate conditioning solution. The entire potassium humate conditioning solution is sprayed onto the porous mineral skeleton to make the moisture content of the porous mineral skeleton reach 13.8%, thus obtaining a low-moisture humic acid pre-attached mineral skeleton. The remaining 1.38 kg of potassium humate is mixed with coconut coir fiber and decomposed organic matter in step S5.

[0086] In step S3, the total mass of atomized water replenishment was 3.8 kg. In the first stage, 0.32 kg of hemihydrated cellulose water-retaining component was added, along with 1.2 kg of atomized water replenishment, and the mixture was stirred for 5 minutes. In the second stage, 0.34 kg of hemihydrated cellulose water-retaining component was added, along with 1.6 kg of atomized water replenishment, and the mixture was stirred for 6 minutes. In the third stage, 0.14 kg of hemihydrated cellulose water-retaining component was added, along with 1 kg of atomized water replenishment, and the mixture was stirred for 10 minutes, resulting in a hemihydrated water-retaining mineral framework. After step S3, the moisture content of the material was measured to be 22.1%.

[0087] In step S3, W0 was measured to be 1.43 kg, W1 to be 1.63 kg, W2 to be 1.88 kg, and W3 to be 2.08 kg.

[0088] Therefore, we can conclude that: (W2-W1) 2 / [(W1-W0)(W3-W2)]=1.56; (W3-W0) / W0=0.455.

[0089] In step S4, 0.06 kg of the calcium-magnesium fixation component is used to prepare a light calcium-magnesium fixation solution, containing 0.04 kg of calcium lactate and 0.02 kg of magnesium sulfate, which is added to 2.5 kg of water to obtain the light calcium-magnesium fixation solution. The total concentration of calcium and magnesium ions in this light calcium-magnesium fixation solution is 0.14 mol / L. After spraying, mixing continues for 18 minutes to obtain a water film-fixed mineral framework. After step S4, the moisture content of the material is 28.4%. The remaining 0.44 kg of calcium-magnesium fixation component is added together with the slow-release nutrient group in step S6.

[0090] In step S6, the final moisture content is adjusted to 30%, and the soil is left to stand at 25°C for 30 hours to obtain water-retaining and fertilizer-retaining artificial planting soil.

[0091] Example 3 This embodiment discloses a water-retaining and fertilizer-retaining artificial planting soil and its preparation method. The difference from Embodiment 1 is that this embodiment uses a higher amount of hemihydrated cellulose water-retaining regulating component, a higher amount of atomized water replenishment, and a higher amount of slow-release nutrient component.

[0092] In this embodiment, based on 100 kg of dry artificial planting soil, the following raw materials are included: 12kg expanded perlite, 9kg vermiculite, 8kg zeolite granules, 28kg coconut coir fiber, 20kg decomposed organic matter, 3.5kg potassium humate, 2kg hemihydrated cellulose water-retaining and regulating components, 1.5kg calcium and magnesium fixing components, 6kg slow-release nutrient components, and 10kg microbial organic fertilizer.

[0093] The mass ratio of expanded perlite, vermiculite, and zeolite particles is 100:75:66.7.

[0094] The hemihydrated cellulose water-retaining and regulating component consists of sodium carboxymethyl cellulose, sodium alginate, and cross-linked potassium polyacrylate, with a mass ratio of 100:40:60. Based on a total mass of 2 kg of the hemihydrated cellulose water-retaining and regulating component, sodium carboxymethyl cellulose accounts for 1 kg, sodium alginate for 0.4 kg, and cross-linked potassium polyacrylate for 0.6 kg.

[0095] In step S2, 0.18 kg of potassium humate is added to 4.32 kg of water to prepare a 4% potassium humate conditioning solution. The entire potassium humate conditioning solution is sprayed onto the porous mineral skeleton to make the moisture content of the porous mineral skeleton reach 15.2%, thus obtaining a low-moisture humic acid pre-attached mineral skeleton. The remaining 3.32 kg of potassium humate is mixed with coconut coir fiber and decomposed organic matter in step S5.

[0096] In step S3, the total mass of atomized water replenishment is 6 kg. In the first stage, 0.8 kg of hemihydrated cellulose water-retaining component is added, along with 1.9 kg of atomized water replenishment, and the mixture is stirred for 5 minutes. In the second stage, 0.85 kg of hemihydrated cellulose water-retaining component is added, along with 2.5 kg of atomized water replenishment, and the mixture is stirred for 7 minutes. In the third stage, 0.35 kg of hemihydrated cellulose water-retaining component is added, along with 1.6 kg of atomized water replenishment, and the mixture is stirred for 12 minutes, resulting in a hemihydrated water-retaining mineral framework. After step S3, the moisture content of the material was measured to be 25.5%.

[0097] In step S3, W0 was measured to be 1.50 kg, W1 to be 1.84 kg, W2 to be 2.25 kg, and W3 to be 2.44 kg.

[0098] Therefore, we can conclude that: (W2-W1) 2 / [(W1-W0)(W3-W2)]==2.60; (W3-W0) / W0==0.627.

[0099] In step S4, 0.11 kg of the calcium-magnesium fixation component was used to prepare a light calcium-magnesium fixation solution, containing 0.073 kg of calcium lactate and 0.037 kg of magnesium sulfate, which was added to 3.6 kg of water to obtain the light calcium-magnesium fixation solution. The total concentration of calcium and magnesium ions in this light calcium-magnesium fixation solution was 0.178 mol / L. After spraying, mixing was continued for 20 minutes to obtain a water film-fixed mineral framework. After step S4, the moisture content of the material was 29.8%. The remaining 1.39 kg of calcium-magnesium fixation component was added together with the slow-release nutrient group in step S6.

[0100] In step S6, the final moisture content is adjusted to 34%, and the soil is left to stand at 25°C for 36 hours to obtain water-retaining and fertilizer-retaining artificial planting soil.

[0101] Example 4 This embodiment discloses a water-retaining and fertilizer-retaining artificial planting soil and its preparation method. The difference from Embodiment 1 is that this embodiment increases the relative proportion of zeolite particles in the porous mineral framework to enhance the nutrient ion buffering effect.

[0102] In this embodiment, based on 100 kg of dry artificial planting soil, the following raw materials are included: 10kg expanded perlite, 6kg vermiculite, 7kg zeolite granules, 34kg coconut coir fiber, 24kg decomposed organic matter, 2.8kg potassium humate, 1.2kg hemihydrated cellulose water-retaining and regulating component, 1kg calcium and magnesium fixing component, 5kg slow-release nutrient component, and 9kg microbial organic fertilizer.

[0103] The mass ratio of expanded perlite, vermiculite, and zeolite particles is 100:60:70.

[0104] The hemihydrated cellulose water-retaining and regulating component consists of sodium carboxymethyl cellulose, sodium alginate, and cross-linked potassium polyacrylate in a mass ratio of 100:30:40. Based on a total mass of 1.2 kg for the hemihydrated cellulose water-retaining and regulating component, sodium carboxymethyl cellulose comprises 0.706 kg, sodium alginate 0.212 kg, and cross-linked potassium polyacrylate 0.282 kg.

[0105] In step S2, 0.16 kg of potassium humate was added to 3.84 kg of water to prepare a 4% potassium humate conditioning solution. The entire solution was sprayed onto the porous mineral skeleton to achieve a moisture content of 14.7%, thus obtaining a low-moisture humic acid pre-attached mineral skeleton. The remaining 2.64 kg of potassium humate was mixed with coconut coir fiber and decomposed organic matter in step S5.

[0106] In step S3, the total mass of atomized water replenishment is 4.5 kg. In the first stage, 0.48 kg of hemihydrated cellulose water-retaining component is added, along with 1.45 kg of atomized water replenishment, and the mixture is stirred for 5 minutes. In the second stage, 0.52 kg of hemihydrated cellulose water-retaining component is added, along with 1.9 kg of atomized water replenishment, and the mixture is stirred for 6 minutes. In the third stage, 0.2 kg of hemihydrated cellulose water-retaining component is added, along with 1.15 kg of atomized water replenishment, and the mixture is stirred for 10 minutes, resulting in a hemihydrated water-retaining mineral framework. After step S3, the moisture content of the material was measured to be 24%.

[0107] In step S3, W0 was measured to be 1.55 kg, W1 to be 1.80 kg, W2 to be 2.12 kg, and W3 to be 2.38 kg.

[0108] Therefore, we can conclude that: (W2-W1) 2 / [(W1-W0)(W3-W2)]==1.58; (W3-W0) / W0=0.535.

[0109] In step S4, 0.09 kg of the calcium-magnesium fixation component is used to prepare a calcium-magnesium light fixation solution, containing 0.06 kg of calcium lactate and 0.03 kg of magnesium sulfate, which is added to 3 kg of water to obtain the calcium-magnesium light fixation solution. The total concentration of calcium and magnesium ions in this calcium-magnesium light fixation solution is 0.175 mol / L. After spraying, mixing continues for 18 minutes to obtain a water film-fixed mineral framework. After step S4, the material moisture content is 29.2%. The remaining 0.91 kg of calcium-magnesium fixation component is added together with the slow-release nutrient group in step S6.

[0110] In step S6, the final moisture content is adjusted to 32%, and the soil is left to stand at 25°C for 30 hours to obtain water-retaining and fertilizer-retaining artificial planting soil.

[0111] Example 5 This embodiment discloses a water-retaining and fertilizer-retaining artificial planting soil and its preparation method. The difference from Embodiment 1 is that the proportion of the three additions in step S3 is adjusted in this embodiment to make the semi-hydration expansion effect of the second stage more concentrated.

[0112] The raw material composition, raw material specifications, steps S1, S2, S4, S5 and S6 in this embodiment are the same as in embodiment 1, the only difference being step S3.

[0113] In step S3, the total mass of atomized water replenishment remains 5 kg. In the first stage, 0.49 kg of hemihydrated cellulose water-retaining and regulating component is added, accounting for 35% of the total mass of the hemihydrated cellulose water-retaining and regulating component; simultaneously, 1.4 kg of atomized water is replenished, accounting for 28% of the total mass of atomized water replenishment. The mixture is mixed for 5 minutes to obtain the first-stage hemihydrated mineral skeleton.

[0114] In the second stage, 0.7 kg of hemihydrated cellulose water-retaining and regulating component was added, accounting for 50% of the total mass of the hemihydrated cellulose water-retaining and regulating component; at the same time, 2.4 kg of atomized water was added, accounting for 48% of the total mass of atomized water. After mixing for 8 minutes, the second-stage hemihydrated mineral skeleton was obtained.

[0115] In the third stage, 0.21 kg of hemihydrated cellulose water-retaining and regulating component was added, accounting for 15% of the total mass of the hemihydrated cellulose water-retaining and regulating component; at the same time, 1.2 kg of atomized water was added, accounting for 24% of the total mass of atomized water. After mixing for 12 minutes, a hemihydrated water-retaining mineral skeleton was obtained.

[0116] After step S3 was completed, the moisture content of the material was measured to be 24.6%.

[0117] In step S3, W0 was measured to be 1.46 kg, W1 to be 1.68 kg, W2 to be 2.06 kg, and W3 to be 2.29 kg.

[0118] Therefore, we can conclude that: (W2-W1) 2 / [(W1-W0)(W3-W2)]==2.85; (W3-W0) / W0=0.568.

[0119] Comparative Example Comparative Example 1 This comparative example discloses an artificial planting soil and its preparation method. The difference from Example 1 is that it does not perform low-moisture humic acid pre-attachment, three-stage semi-hydration treatment, calcium and magnesium light fixation and post-nutrient balancing, but adopts a one-time mixing method.

[0120] Specifically, 12 kg of expanded perlite, 8 kg of vermiculite, 8 kg of zeolite granules, 32 kg of coconut coir fiber, 22 kg of decomposed organic matter, 2.4 kg of potassium humate, 1.4 kg of hemihydrated cellulose water-retaining and regulating component, 1 kg of calcium and magnesium fixing component, 4.8 kg of slow-release nutrient component, and 8.4 kg of microbial organic fertilizer were added to a horizontal paddle mixer at once and mixed for 25 minutes at 35 r / min. Then, water was added by atomization to the moisture content to 31%, and the mixture was allowed to stand at 25℃ for 30 hours to obtain artificial planting soil.

[0121] In this comparative example, the total amount of each component is the same as in Example 1.

[0122] Comparative Example 2 This comparative example discloses an artificial planting soil and its preparation method. The difference from Example 1 is that potassium humate conditioning solution is not used for low-moisture humic acid pre-attachment in step S2.

[0123] Specifically, in step S2, only 3.6 kg of clean water is sprayed onto the porous mineral skeleton to make the moisture content of the porous mineral skeleton reach 14.2%, thus obtaining a low-moisture mineral skeleton; 2.4 kg of potassium humate is mixed together with coconut coir fiber and decomposed organic matter in step S5.

[0124] Apart from the differences mentioned above, the composition of the raw materials and steps S3 to S6 are the same as in Example 1.

[0125] Comparative Example 3 This comparative example discloses an artificial planting soil and its preparation method. The difference from Example 1 is that in step S3, instead of using three-stage addition and three-stage atomized water replenishment, the hemihydrated cellulose water-retaining and regulating component is added and atomized water replenishment is performed all at once.

[0126] Specifically, in step S3, 1.4 kg of hemihydrated cellulose water-retaining and regulating component is added at once to the low-moisture humic acid pre-attached mineral skeleton obtained in step S2, and 5 kg of water is added at once by atomization. The mixture is mixed for 21 min at 45 r / min to obtain the water-retaining mineral skeleton.

[0127] Except for the differences mentioned above, the other raw material composition, steps S1, S2, and steps S4 to S6 are the same as in Example 1.

[0128] Comparative Example 4 This comparative example discloses an artificial planting soil and its preparation method. The difference from Example 1 is that in step S3, the hemihydrated cellulose water-retaining and regulating component absorbs water to form a gel before being added.

[0129] Specifically, 1.4 kg of hemihydrated cellulose water-retaining conditioning component is mixed with 5 kg of water and allowed to stand for 30 min to absorb water, forming a pre-absorbed hydrogel; then the pre-absorbed hydrogel is added to the low-moisture humic acid pre-attached mineral skeleton obtained in step S2, and mixed at 45 r / min for 21 min to obtain a water-retaining mineral skeleton.

[0130] Except for the differences mentioned above, the other raw material composition, steps S1, S2, and steps S4 to S6 are the same as in Example 1.

[0131] Comparative Example 5 This comparative example discloses an artificial planting soil and its preparation method. The difference from Example 1 is that the calcium-magnesium light fixative is added before step S3.

[0132] Specifically, after step S2 is completed, the calcium-magnesium light fixative solution prepared by 0.06 kg of calcium lactate, 0.03 kg of magnesium sulfate and 3 kg of water is sprayed onto the low-moisture humic acid pre-attached mineral skeleton for 12 min. The mixing speed during the spraying process is 35 r / min. After the spraying is completed, mixing continues for 18 min. Then, the hemihydrated cellulose water-retaining and regulating component is added according to step S3 of Example 1 and three-stage atomization water replenishment is performed.

[0133] Except for the different order of addition of the calcium and magnesium fixative solution, the composition of the raw materials and the process parameters are the same as in Example 1. The remaining 0.91 kg of calcium and magnesium fixative component is added in step S6.

[0134] Comparative Example 6 This comparative example discloses an artificial planting soil and its preparation method. The difference from Example 1 is that the slow-release nutrient group and microbial organic fertilizer are added in advance, and nutrient balancing is not performed afterward.

[0135] Specifically, after preparing the porous mineral framework in step S1, 3 kg of coated compound fertilizer, 0.75 kg of ammonium humate, 1.05 kg of potassium magnesium sulfate, 8.4 kg of microbial organic fertilizer, and 0.91 kg of calcium magnesium fixation component not added in step S4 are added to the porous mineral framework and mixed at 30 r / min for 10 min. Then, the preparation is carried out according to steps S2 to S5 of Example 1. After step S5, only the final moisture content is adjusted to 31%, and no further addition of slow-release nutrient components is made.

[0136] Apart from the differences mentioned above, the other raw material composition and process parameters are the same as in Example 1.

[0137] Performance testing To verify the technical effectiveness of the water-retaining and fertilizer-retaining artificial planting soil prepared according to this invention, performance tests were conducted on the samples obtained in Examples 1-5 and Comparative Examples 1-6. Before testing, each sample was equilibrated at 25°C for 24 hours, and after removing obvious large impurities, it was mixed thoroughly before sampling. Three parallel samples were set up for each test item, and the average value of the test results was taken.

[0138] 1. Saturated water holding capacity test Take 500g of naturally balanced artificial planting soil sample and record its wet weight. Take another sample from the same batch to determine its moisture content and calculate its dry weight. Place the sample in a cylindrical container with a filter at the bottom, with an inner diameter of 10cm and a height of 15cm. Slowly add water to the container until the water level is 2cm above the sample surface, and let it soak for 30 minutes. Then remove the container and allow it to drain freely at room temperature for 30 minutes. Weigh the sample after drainage. The saturated water holding capacity is calculated as the percentage of the water content of the sample after drainage to its dry weight.

[0139] 2. Test of saturated water holding capacity retention rate after wet-dry cycle After completing the saturated water holding capacity test, the sample was placed in a 40℃ forced-air drying oven and dried until its mass was close to the initial dry basis mass. Then, water was reabsorbed and freely drained according to the saturated water holding capacity test method, constituting one wet-dry cycle. Ten consecutive wet-dry cycles were performed, and the saturated water holding capacity after the tenth cycle was measured. The saturated water holding capacity retention rate after wet-dry cycles was calculated as the percentage of the saturated water holding capacity after the tenth cycle to the saturated water holding capacity after the first cycle.

[0140] 3. Ventilation porosity testing The aeration porosity was determined using the ring cutter method. A ring cutter with an inner diameter of 5 cm and a height of 5 cm was used. The sample was naturally filled into the ring cutter, and the surface was gently leveled to ensure uniform filling of all samples. The ring cutter containing the sample was slowly immersed in water until saturated, allowed to stand for 30 minutes, and then removed. The water was allowed to drain freely for 30 minutes, and the volume of water retained in the sample after saturation and drainage was measured. The total pore volume and the pore volume occupied by water were then calculated based on the total volume of the ring cutter and the dry basis mass of the sample. The aeration porosity was calculated as the percentage of pore volume not occupied by water after drainage relative to the total volume of the ring cutter.

[0141] 4. Initial extract conductivity test Take 20g of air-dried artificial planting soil sample to equilibrium, add 100mL of deionized water, and extract at a mass-to-volume ratio of 1:5. After mixing the sample with deionized water, shake for 30min, let stand for 10min, collect the supernatant, and measure the conductivity of the extract using a conductivity meter. The detection temperature is controlled at 25℃.

[0142] 5. Continuous rinsing fluid conductivity testing Take 300g of artificial planting soil sample and fill it into a leaching column with an inner diameter of 6cm to a height of 15cm. Add 300mL of deionized water each time, allow it to seep naturally, and collect all the leaching solution. Repeat the leaching process 5 times, with an interval of 2 hours between each leaching. Measure the conductivity of the leaching solution after the 1st, 3rd, and 5th leaching cycles.

[0143] 6. Ammonium nitrogen retention rate detection 300g of artificially planted soil sample was placed into a leaching column and leached five times consecutively using the continuous leaching conductivity detection method. The five leaching solutions were combined. The ammonium nitrogen content in the combined leaching solution was determined using Nessler's reagent spectrophotometry. Simultaneously, the extractable ammonium nitrogen content in the unleached sample was also determined. The ammonium nitrogen retention rate was calculated as the percentage of ammonium nitrogen retained in the leached sample relative to the extractable ammonium nitrogen in the unleached sample.

[0144] 7. Test of available potassium retention rate Take 300g of artificial planting soil sample and rinse it 5 times consecutively according to the continuous leaching solution conductivity test method. Before and after leaching, extract the available potassium in the sample with 1mol / L ammonium acetate solution, and determine the potassium content by flame photometry. The available potassium retention rate is calculated as the percentage of available potassium content in the sample after leaching to the available potassium content in the sample before leaching.

[0145] 8. Germination Index Detection Each sample was placed in a seedling tray, 50g per well, with 50 Chinese cabbage seeds per sample. The trays were covered with approximately 0.5cm of soil and incubated at 25℃ and 70% relative humidity. An equal amount of water was added daily after sowing to keep the samples moist but not waterlogged. Germination potential was recorded on day 3, and germination rate on day 7. Root length was measured on 20 randomly selected seedlings. The germination index was calculated as the percentage of the product of the germination rate and average root length of the sample relative to the corresponding value under the control culture condition (water filter paper).

[0146] The test results are shown in Table 1-4.

[0147] Table 1. Test results of water retention and air permeability of each sample. As shown in Table 1, the saturated water holding capacity of Examples 1-5 ranged from 105.3% to 139.8%, and the saturated water holding capacity retention rate after 10 wet-dry cycles was no less than 84.1%, while the aeration porosity remained between 20.6% and 27.6%. This indicates that the artificial planting soil obtained in these examples improved water holding capacity while still retaining good air channels. Although Comparative Examples 3 and 4 had higher saturated water holding capacity, their aeration porosity was significantly reduced, and continuous gel clusters appeared, indicating that one-time hydration or the addition of pre-absorbed hydrogels easily leads to local concentration of water-retaining components, affecting the interparticle porosity.

[0148] Table 2. Results of conductivity tests for initial extract and continuous eluent for each sample. As shown in Table 2, the initial extract conductivity of Examples 1-5 ranged from 1.05 to 1.43 mS / cm, all within a relatively stable range. Example 3, due to the higher dosage of the slow-release nutrient components, had a relatively higher conductivity, but it remained below 1.6 mS / cm. In Comparative Example 6, the nutrient components were added earlier, resulting in a significant increase in both the initial extract conductivity and the conductivity of the first eluent, indicating that post-addition of nutrients and static equilibration are beneficial in reducing the concentrated release of soluble salts in the initial stage. The higher conductivity of the first eluent in Comparative Examples 1, 3, and 4 indicates that ordinary one-time mixing, one-time hydration, or pre-absorbed hydrogel states are not conducive to stable initial salt release.

[0149] Table 3. Results of ammonium nitrogen retention rate and available potassium retention rate for each sample. As shown in Table 3, Examples 1-5 maintained high retention rates of ammonium nitrogen and available potassium after five consecutive rinsings. Example 4, with its higher proportion of zeolite particles, exhibited particularly high retention rates of both ammonium nitrogen and available potassium. These results indicate that the combined effects of low-moisture humic acid pre-attachment, semi-hydrated water film formation, calcium and magnesium light fixation, and post-nutrient balancing can achieve a better overlap between the moisture retention zone and the nutrient buffer zone, thereby reducing the tendency for nutrients to migrate rapidly with water.

[0150] Table 4. Results of Germination and Early Seedling Growth Detection for Each Sample of Bok Choy As shown in Table 4, the germination rate of the bok choy in Examples 1-5 was no less than 91% on day 7, and the germination index was no less than 85.6%. This indicates that the artificial planting soil obtained in these examples not only has water and fertilizer retention capacity, but also that the initial salt release and aeration conditions are suitable for seed germination and seedling root growth. The lower germination indices of Comparative Examples 4 and 6 are mainly related to the reduced aeration porosity or the higher initial electrical conductivity, further demonstrating that the semi-hydrated thin-layer state and the low-salt balance of post-nutrient placement have a positive effect on seedling safety.

[0151] In summary, this invention achieves a better balance between high water retention capacity, good aeration, and low nutrient leaching in artificial planting soil through low-moisture humic acid pre-attachment, three-stage semi-hydrated water film formation, calcium and magnesium light fixation, and post-nutrient balancing.

[0152] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a water-retaining and fertilizer-retaining artificial planting soil, characterized in that, Includes the following steps: S1: Mix expanded perlite, vermiculite and zeolite particles to obtain a porous mineral framework; S2: Apply potassium humate conditioning solution to the porous mineral framework to make the water content of the porous mineral framework reach 10% to 18%, and after mixing, a low-moisture humic acid pre-attached mineral framework is obtained. S3: The hemihydrated cellulose water-retaining and regulating component is added to the low-moisture humic acid pre-attached mineral skeleton in several batches, and water is added by atomization during the addition process, so that the moisture content of the material increases from 10% to 18% to 18% to 26%, and a hemihydrated water-retaining mineral skeleton is obtained. S4: The calcium-magnesium light fixation solution is sprayed into the semi-hydrated water-retaining mineral skeleton so that the moisture content of the material reaches 22% to 30%, and after mixing, a water film fixed mineral skeleton is obtained. S5: Mix the water-film-fixed mineral skeleton with coconut coir fiber and decomposed organic matter to obtain a water-retaining planting soil substrate; S6: Add the slow-release nutrient group and microbial organic fertilizer to the water-retaining planting soil substrate, mix and adjust the final moisture content to 26% to 36%, and let it stand at 15 to 30℃ for 18 to 48 hours to obtain water-retaining and fertilizer-retaining artificial planting soil. The hemihydrated cellulose water-retaining and regulating components include sodium carboxymethyl cellulose, sodium alginate, and cross-linked potassium polyacrylate.

2. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 1, characterized in that, Based on 100 parts of the dry weight of the water-retaining and fertilizer-retaining artificial planting soil, the expanded perlite comprises 8-18 parts, the vermiculite comprises 5-14 parts, the zeolite particles comprise 5-13 parts, the coconut coir fiber comprises 25-40 parts, the decomposed organic matter comprises 15-28 parts, the potassium humate comprises 1.0-4.0 parts, the hemihydrated cellulose water-retaining and regulating component comprises 0.6-2.2 parts, the calcium and magnesium fixing component comprises 0.4-2.0 parts, a portion of which is used to prepare a calcium and magnesium light fixation solution; the slow-release nutrient group comprises 2.5-7.0 parts, and the microbial organic fertilizer comprises 3-10 parts.

3. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 1, characterized in that, In step S1, the mass ratio of the expanded perlite, the vermiculite, and the zeolite particles is 100:35-75:30-70; the particle size of the expanded perlite is 1-4 mm, the particle size of the vermiculite is 0.5-3 mm, and the particle size of the zeolite particles is 0.3-2 mm.

4. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 1, characterized in that, In step S1, the zeolite particles are clinoptilolite particles, and the cation exchange capacity of the clinoptilolite particles is 80-160 cmol / kg; in step S2, the mass concentration of potassium humate in the potassium humate conditioning solution is 1.0%-4.0%, and the pH is 7.5-9.

0.

5. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 1, characterized in that, In step S3, the mass ratio of sodium carboxymethyl cellulose, sodium alginate, and crosslinked potassium polyacrylate is 100:15-45:20-70.

6. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 1, characterized in that, In step S3, the hemihydrated cellulose water-retaining and regulating component is added to the low-moisture humic acid pre-attached mineral skeleton in three stages, and atomized water replenishment is performed during the three stages of addition. The first stage involves adding 30%–45% of the total mass of the hemihydrated cellulose water-retaining and regulating components, and adding 25%–38% of the total mass of atomized water replenishment. Mix for 3–6 minutes to obtain the first stage of hemihydrated mineral skeleton. In the second stage, 35% to 50% of the total mass of the hemihydrated cellulose water-retaining and regulating components are added, along with 35% to 48% of the total mass of atomized water replenishment. The mixture is then stirred for 4 to 8 minutes to obtain the second-stage hemihydrated mineral skeleton. In the third stage, 15% to 30% of the total mass of the hemihydrated cellulose water-retaining and regulating components are added, along with 18% to 32% of the total mass of atomized water replenishment. The mixture is then stirred for 6 to 12 minutes to obtain the hemihydrated water-retaining mineral skeleton.

7. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 6, characterized in that, The water holding increment in step S3 satisfies the following relationship: Wherein, W0 is the water-holding mass of the low-moisture humic acid pre-attached mineral skeleton after saturation water absorption and free drainage for 30 minutes, measured by sampling before step S3, in kg; W1 is the water-holding mass of the first-stage semi-hydrated mineral skeleton after saturation water absorption and free drainage for 30 minutes, in kg; W2 is the water-holding mass of the second-stage semi-hydrated mineral skeleton after saturation water absorption and free drainage for 30 minutes, in kg; and W3 is the water-holding mass of the semi-hydrated water-retaining mineral skeleton after saturation water absorption and free drainage for 30 minutes, in kg.

8. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 1, characterized in that, In step S4, the calcium-magnesium light fixative solution is prepared from calcium lactate, magnesium sulfate, and water, with a mass ratio of calcium lactate to magnesium sulfate of 100:20-80. The total concentration of calcium and magnesium ions in the calcium-magnesium light fixative solution is 0.03-0.18 mol / L. The calcium-magnesium light fixative solution is sprayed into the semi-hydrated water-retaining mineral framework by atomization for 6-18 minutes. During the spraying process, the mixing speed is 25-50 r / min, and mixing continues for 10-25 minutes after spraying.

9. The method for preparing water-retaining and fertilizer-retaining artificial planting soil according to claim 1, characterized in that, In step S5, the moisture content of the coconut coir fiber before mixing is 12% to 22%, and the moisture content of the decomposed organic matter before mixing is 18% to 32%. In step S6, the slow-release nutrient group includes coated compound fertilizer, ammonium humate, and potassium magnesium sulfate.

10. A water-retaining and fertilizer-retaining artificial planting soil, characterized in that, The soil is prepared by the method described in any one of claims 1 to 9; the saturated water holding capacity of the water-retaining and fertilizer-retaining artificial planting soil is 85% to 150% of its own dry basis mass, the saturated water holding capacity retention rate is not less than 82% after 10 dry-wet cycles, the aeration porosity is 18% to 32%, and the initial extract conductivity is 0.6 to 1.6 mS / cm.

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