Ecological planting soil capable of recycling stone waste residues and mud cakes and preparation method of ecological planting soil

Abstract

The invention provides ecological planting soil capable of recycling stone waste residues and mud cakes and a preparation method of the ecological planting soil, and belongs to the technical field of ecological planting soil. Structural oxygen-containing functional groups of mineral source high-activity potassium humate are utilized to be subjected to complex reaction with soil and water and fertilizer, soil structure improvement of a planting matrix is promoted, the content of medium-large soil aggregates is increased, and soil acid-base balance is adjusted; the polymer water-retaining material promotes the formation of a soil aggregate structure and enhances the water-retaining and fertilizer-retaining capabilities of the soil; the decomposed organic matters contain various organic nutrients, so that the soil structure can be improved; the active components in the soil adhesive react with water and mineral substances to generate a gel substance which can effectively bond sand grains and powder grains and provide a large amount of iron ions; the soil microorganism complex microbial inoculant can promote mineral decomposition and soil organic matter decomposition, and finally ecological planting soil which has a good soil granular structure, water and fertilizer retention capacity and soil microorganism activity and can promote plant growth is obtained.

Description

Technical Field

[0001] This invention relates to the field of ecological planting soil technology, and in particular to an ecological planting soil that recycles stone waste and mud cake and its preparation method. Background Technology

[0002] The mining of building materials and stone will generate a large amount of waste residue such as stone powder and wastewater treatment mud cake from washing the stone. The large accumulation of stone waste residue and mud cake not only occupies land, but also causes environmental pollution such as dust and soil erosion.

[0003] Meanwhile, mine ecological restoration faces the problem of topsoil resource shortage. Therefore, with the development of the circular economy and the acceleration of solid waste resource utilization, the comprehensive utilization of stone slag and wastewater treatment sludge to prepare artificial soil, namely ecological planting soil, has become an important direction for solid waste resource utilization.

[0004] Stone waste is mainly composed of silicate minerals such as quartz and feldspar, with a high pH (8.0~11.0) and extremely low cation exchange capacity (CEC) (<5 cmol / kg), resulting in poor water and fertilizer retention. Wastewater treatment sludge cake, on the other hand, has an excessively high clay content (>40%) and poor permeability. Direct mixing of the two makes it difficult to form a suitable porous structure for plant growth. Current technologies mostly rely on simple mechanical mixing without addressing the high alkalinity of the waste and the high viscosity of the sludge cake, leading to insufficient available phosphorus and potassium in the planting soil, which cannot support long-term plant growth. To avoid deterioration of the physicochemical properties of the planting soil, the amount of stone waste in existing technologies is usually less than 30%, requiring large quantities of waste to be stockpiled. Furthermore, wastewater treatment sludge cake contains small amounts of heavy metal ions (such as Pb). 2+ Cd 2+ Direct use of untreated soil poses environmental risks and limits its resource utilization rate. Existing planting soil technologies are primarily designed for farmland or landscaping, without optimization for mine site conditions, resulting in poor remediation outcomes. Summary of the Invention

[0005] The purpose of this invention is to provide an ecological planting soil that recycles stone waste and mud cake and its preparation method. The ecological planting soil provided by this invention has a good soil aggregate structure, water and fertilizer retention capacity and soil microbial activity, which can promote plant growth.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides an ecological planting soil for recycling stone waste and mud cake, which is prepared from the following raw materials: 30-40 parts stone waste, 60-70 parts mud cake, and 6-8 parts soil conditioner;

[0008] The soil conditioner is composed of mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant; the mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant is (28~38):(52~70):(0.2~1.0):(1~4.5):(0.2~1.2).

[0009] Preferably, the mass ratio of the stone waste residue to the mud cake is (4~3):(6~7).

[0010] Preferably, the mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound agent is (30~35):(58~65):(0.4~0.8):(1~5.5):(0.4~1.0).

[0011] Preferably, the method for preparing the mineral-derived highly active potassium humate includes the following steps: mixing nitric acid solution and weathered coal, and then oxidizing the mixture to obtain highly active weathered coal; mixing the highly active weathered coal with KOH solution, and then subjecting the mixture to alkali treatment to adjust the pH to obtain mineral-derived highly active potassium humate.

[0012] Preferably, the cross-linked polymeric water-retaining material is anionic polyacrylamide (APAM); the molecular weight of the cross-linked polymeric water-retaining material is 1,000,000 to 1,200,000 Daltons.

[0013] Preferably, the method for preparing the composted organic matter includes the following steps: mixing weathered coal, cow dung, corn stalks and compound microorganisms, and then fermenting and composting them to obtain composted organic matter.

[0014] Preferably, the carbon-to-nitrogen ratio of the total raw materials composed of weathered coal, cow dung, and corn stalks is (26~30):1; the fermentation temperature is 35~60℃; the fermentation time is 150~200h; during the fermentation process, the moisture content of the fermentation system is maintained at 45wt%~49wt%; and air is introduced into the fermentation system at a flow rate of 0.15 L / min.

[0015] Preferably, the soil binder is a ferrous sulfate binder with a purity ≥90% and an iron content ≥18.1%.

[0016] Preferably, the soil microbial compound inoculant is composed of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis; the mass ratio of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis is 1:0.5:0.3:0.5.

[0017] This invention also provides a method for preparing the ecological planting soil described in the above technical solution, characterized by comprising the following steps:

[0018] A soil conditioner is obtained by mixing mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining materials, soil binders, and soil microbial compound inoculants.

[0019] After mixing stone waste, mud cake and soil conditioner, the mixture is aged to obtain ecological planting soil that recycles stone waste and mud cake.

[0020] This invention provides an ecological planting soil that recycles stone waste and mud cake. Utilizing the oxygen-containing functional groups (carboxyl, hydroxyl, carbonyl, quinone, methoxy, etc.) on the structure of highly active potassium humate derived from minerals, it can undergo complex reactions with soil and water / fertilizer, effectively promoting soil structure improvement, increasing the content of medium and large soil aggregates, regulating soil pH balance, increasing soil organic matter content, significantly improving soil quality, and providing a substrate for soil microorganisms. The high-molecular water-retaining material is a cross-linked polyacrylate with good anionic and cation exchange capacity, which can form valence bonds with soil particles to promote soil aggregate formation, enhance soil water and fertilizer retention capacity, and benefit plants. The composted organic matter contains a large amount of small-molecule bio-humic acid and other organic nutrients, which can improve soil structure and provide nutrients for microorganisms and plants. The soil binder is an environmentally friendly inorganic cementitious binder with an iron (Fe) content of ≥18.1%. The gel substance generated by the reaction of the active components with water and minerals can effectively bind sand and silt particles. At the same time, a large amount of iron ions can directly supplement the plants with essential elements, realizing the synergistic improvement of the physical and chemical properties of the soil. The soil microbial compound inoculant can promote the decomposition of minerals and soil organic matter, promote the integration of ecological planting soil with the external matrix of ecological restoration, and promote plant growth. This invention optimizes the ratio of stone waste and mud cake, using granite waste with a composition similar to natural soil. It also artificially accelerates rock weathering and soil formation, and by adding a soil conditioner with a specific composition, the prepared ecological planting soil exhibits good soil aggregate structure, water and fertilizer retention capacity, and soil microbial activity. This promotes plant growth and meets the requirements of the "Landscape Greening Planting Soil DB11 / T 864-2020" standard. Nutrient content meets the Level 4 technical requirements of the second national soil grading survey, and As, Cr, Ni, and Cd all meet the requirements of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard GB15618-2018". This provides important material support for mine ecological restoration and a technical approach for the resource utilization of solid waste. Attached Figure Description

[0021] Figure 1This is a graph showing the changes in the physical properties of the greening substrate prepared from mud cake and stone waste in this invention. Figure 1 In this context, a represents soil bulk density, b represents soil field water holding capacity, c represents soil moisture content, and d represents soil total porosity.

[0022] Figure 2 This is a graph showing the changes in chemical indicators of the greening substrate prepared from mud cake and stone waste in this invention. Figure 2 The left and right graphs show soil pH and soil electrical conductivity, respectively.

[0023] Figure 3 This is a graph showing the effect of different treatment composite environmental materials on the fresh and dry weight of ryegrass in this invention.

[0024] Figure 4 This is a graph showing the effect of different treatment composite environmental materials on the fresh and dry weight of ryegrass in this invention.

[0025] Figure 5 This is a graph showing the effects of different treatment composite environmental materials on the plant height and root length of ryegrass in this invention;

[0026] Figure 6 This is a graph showing the effect of different post-planting treatments of composite environmental materials on the pH of soil-forming materials in this invention.

[0027] Figure 7 This is a graph showing the effect of different post-planting treatments of composite environmental materials on the electrical conductivity of soil-forming materials in this invention.

[0028] Figure 8 This is a graph showing the effect of different post-planting treatments of composite environmental materials on the cation exchange capacity of soil-forming materials in this invention.

[0029] Figure 9 This is a diagram showing the effect of different post-planting treatments of composite environmental materials on the organic matter content of soil-forming materials in this invention.

[0030] Figure 10 This figure shows the effects of different post-planting treatments of the composite environmental material on the alkaline nitrogen, available phosphorus, and readily available potassium of the soil-forming material. Detailed Implementation

[0031] This invention provides an ecological planting soil for recycling stone waste and mud cake, which is prepared from the following raw materials: 30-40 parts stone waste, 60-70 parts mud cake, and 6-8 parts soil conditioner;

[0032] The soil conditioner is composed of mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant; the mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant is (28~38):(52~70):(0.2~1.0):(1~4.5):(0.2~1.2).

[0033] Unless otherwise specified, all raw materials used in this invention are commercially available products in the art.

[0034] In this invention, the preferred mass ratio of the stone waste residue to the mud cake is (4~3):(6~7). By controlling the mass ratio of the stone waste residue to the mud cake within the above range, the soil bulk density can be maintained at 1.28 g / cm³. 3 Below, the field water holding capacity can be maintained above 30%, the soil porosity of the prepared substrate is significantly improved, and the soil pH is effectively increased. In this invention, the preferred mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymeric water-retaining material, soil binder, and soil microbial compound agent is (30~35):(58~65):(0.4~0.8):(1~5.5):(0.4~1.0), more preferably (31.5~34):(60~64):(0.5~0.7):(2~4.5):(0.5~0.9), and even more preferably 33.5:62.8:0.6:2.5:0.7. By controlling the mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymeric water-retaining material, soil binder, and soil microbial compound agent within the above range, the soil bulk density can be further reduced to a suitable soil level (1.00~1.25 g / cm³). 3 The soil porosity and water retention capacity were significantly improved, and the soil CEC, soil organic matter, and nutrients such as nitrogen, phosphorus and potassium were also significantly increased.

[0035] In this invention, the method for preparing the mineral-derived highly active potassium humate preferably includes the following steps: mixing nitric acid solution and weathered coal, and then oxidizing the mixture to obtain highly active weathered coal; mixing the highly active weathered coal with KOH solution, and then subjecting the mixture to alkali treatment to adjust the pH to obtain mineral-derived highly active potassium humate.

[0036] In this invention, the concentration of the nitric acid solution is preferably 2.6 mol / L; the liquid-to-solid ratio of the nitric acid solution to the weathered coal is preferably 2.8~4.2 mL / g, more preferably 3~4 mL / g, and even more preferably 3.6 mL / g. In this invention, the oxidation time is preferably 20~40 min, more preferably 28 min; the oxidation temperature is preferably 60~100℃. In this invention, the concentration of the KOH solution is preferably 0.8 mL / g. In this invention, the temperature for adjusting the pH using alkali treatment is 40~60℃; the time for adjusting the pH using alkali treatment is 80~120 min. This invention utilizes oxidation to disrupt the cross-linked structure of macromolecules in weathered coal, increasing oxygen-containing functional groups and transforming macromolecular, insoluble humic substances into soluble or extractable forms. Alkali treatment is then used to adjust the pH, achieving a neutralization reaction. This process converts acidic functional groups such as carboxyl groups in the oxidation products into soluble potassium salts, thereby dissolving and purifying the products. The result is a mineral-derived, highly active potassium humate with an organic matter content exceeding 70% and a soluble fulvic acid content of up to 65%.

[0037] In this invention, the cross-linked polymeric water-retaining material is preferably anionic polyacrylamide (APAM); the molecular weight of the cross-linked polymeric water-retaining material is preferably 1,000,000 to 1,200,000 Daltons.

[0038] In this invention, the method for preparing the composted organic matter preferably includes the following steps: mixing weathered coal, cow dung, corn stalks and compound microorganisms, and then fermenting and composting them to obtain composted organic matter.

[0039] In this invention, the carbon-to-nitrogen ratio of the total raw materials composed of weathered coal, cow dung, and corn stalks is preferably (26-30):1, more preferably 28.9:1. This invention controls the carbon-to-nitrogen ratio of the total raw materials within the above range to ensure that the nitrogen source required for energy supply and metabolism by aerobic fermentation microorganisms reaches its optimal level, while simultaneously achieving efficient degradation of organic matter, minimizing nitrogen loss, and promoting humus formation. In this invention, the fermentation temperature is preferably 35-60℃, more preferably controlled at 55-60℃ within 0-50 h of fermentation and at 35-45℃ within 50-200 h of fermentation. The fermentation time is preferably 150-200 h, more preferably 168 h. During the fermentation process, the moisture content of the fermentation system is maintained at 45wt%-49wt%, and air is introduced into the fermentation system at a flow rate of 0.15 L / min. This invention ferments and decomposes cow manure under the above conditions, transforming it into small-molecule biohumic acid rich in fulvic acid and containing a large amount of organic nutrients. At the same time, it degrades and deodorizes, eliminates pests, diseases, and weed seeds, resulting in decomposed organic matter with a maturity of over 80% and an organic matter content of over 35%, providing sufficient nutrients for the growth of microorganisms and plants.

[0040] In this invention, the soil binder is preferably a ferrous sulfate binder with a purity ≥90% and an iron content ≥18.1%, more preferably Shanghai Maclean Biochemical Technology Co., Ltd. I809844. The soil binder in this invention is an environmentally friendly inorganic cementitious binder with an iron (Fe) content ≥18.1%. The gel substance formed by the reaction of the active components with water and minerals can effectively bind sand and silt particles, while the large amount of iron ions can directly supplement essential elements for plants, achieving synergistic improvement of both the physical and chemical properties of the soil.

[0041] In this invention, the soil microbial compound inoculant is composed of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis; the mass ratio of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis is 1:0.5:0.3:0.5. This invention utilizes the above-described soil microbial compound inoculant to promote mineral decomposition and soil organic matter decomposition, promote the integration of ecological planting soil with the external matrix for ecological restoration, and simultaneously promote plant growth.

[0042] This invention also provides a method for preparing the ecological planting soil described in the above technical solution, characterized by comprising the following steps:

[0043] A soil conditioner is obtained by mixing mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining materials, soil binders, and soil microbial compound inoculants.

[0044] After mixing stone waste, mud cake and soil conditioner, the mixture is aged to obtain ecological planting soil that recycles stone waste and mud cake.

[0045] In this invention, the aging temperature is room temperature; the aging time is 10-15 days; and the moisture content of the system during the aging process is preferably 15%-25%. Through aging under the above conditions, this invention allows for sufficient physicochemical reactions between the soil conditioner and the stone waste and mud cake, as well as the succession of soil microorganisms, thereby achieving the stabilization of soil aggregate structure, nutrient buffering, and biological activity.

[0046] In this invention, during the use of the ecological planting soil made from recycled stone waste and mud cake, the surface of the mine landfill can be covered with 10-15 cm of the ecological planting soil made from recycled stone waste and mud cake, or 15-20 cm of the ecological planting soil made from recycled stone waste and mud cake can be laid in the pit before planting plants. The specific depth can be adjusted according to the type of plant. After planting, appropriate water needs to be irrigated, and other general field management is sufficient.

[0047] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0048] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0049] Example 1

[0050] An ecological planting soil that recycles stone waste and mud cake is prepared from the following raw materials: 30 parts stone waste, 70 parts mud cake, and 7 parts soil conditioner.

[0051] The mass ratio of the stone waste residue to the mud cake is 3:7;

[0052] The soil conditioner is composed of mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant; the mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant is 33.5:62.8:0.6:2.5:0.7.

[0053] The method for preparing the mineral-derived highly active potassium humate includes the following steps: mixing 2.6 mol / L nitric acid solution and weathered coal at a liquid-to-solid ratio of 3.6 mL / g, and oxidizing at 80℃ for 28 min to obtain highly active weathered coal; mixing the highly active weathered coal with a 0.8 mg / L KOH solution, and alkali-treating at 50℃ to adjust the pH for 100 min to obtain mineral-derived highly active potassium humate with an organic matter content of 73% and a soluble fulvic acid content of 65%;

[0054] The cross-linked polymer water-retaining material is anionic polyacrylamide (APAM).

[0055] The cross-linked polymer water-retaining material has a molecular weight of 1.2 million Daltons; the method for preparing the decomposed organic matter includes the following steps: mixing weathered coal, cow dung, corn stalks and composite microorganisms, and then fermenting and decomposing them to obtain decomposed organic matter;

[0056] The total raw material, consisting of weathered coal, cow dung, and corn stalks, has a carbon-to-nitrogen ratio of 28.9:1. The fermentation temperature is controlled at 60°C for 0-50 h and at 45°C for 50-168 h. The fermentation time is 168 h. During the fermentation process, the moisture content of the fermentation system is maintained at 49 wt%, and air is introduced into the fermentation system at a flow rate of 0.15 L / min.

[0057] The soil binder is a ferrous sulfate binder, Shanghai Maclean Biochemical Technology Co., Ltd. - I809844, with a purity ≥90% and an iron content ≥18.1%.

[0058] The soil microbial compound inoculant is composed of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis; the mass ratio of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis is 1:0.5:0.3:0.5.

[0059] The preparation method of the ecological planting soil includes the following steps:

[0060] A soil conditioner is obtained by mixing mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining materials, soil binders, and soil microbial compound inoculants.

[0061] After mixing stone waste, mud cake and soil conditioner, the mixture is aged at room temperature for 12 days, with the moisture content of the system maintained at 20% during the aging process, to obtain ecological planting soil that recycles stone waste and mud cake.

[0062] Investigation 1. Study on the ratio of mud cake and stone waste in the preparation of greening substrate

[0063] (1) Experimental setup: The mud cake was a cake-shaped solid obtained by dewatering the wet washing wastewater from the Guanyinshan granite mine, with a fine texture; the stone waste residue was the surface stripping material from the mine, mostly fine sand and gravel. The heavy metal chromium, cadmium, arsenic and mercury content of the mud cake and stone waste residue all met the Class I standard of CJ / T 340-2016 "Greening Planting Soil" and the lead content of the stone waste residue met the Class II standard. Both met the technical requirements for heavy metal content of greening substrate for mine restoration. The heavy metal content test results of the stone waste residue and mud cake used in this invention are shown in Table 1, and the basic physicochemical properties are shown in Table 2.

[0064] Table 1. Heavy metal content (mg / kg) of stone waste residue and mud cake

[0065]

[0066] Table 2. Basic physical and chemical properties of stone waste and mud cake

[0067]

[0068] Mud cake and stone waste were used as raw materials to prepare a greening substrate. Eleven mixing ratios were set: 10:0 (A), 9:1 (B), 8:2 (C), 7:3 (D), 6:4 (E), 5:5 (F), 4:6 (G), 3:7 (H), 2:8 (I), 1:9 (J), and 10:0 (K). Each treatment had three replicates, with 500g of soil per pot placed indoors in the dark for 30 days. After cultivation, the soil bulk density, field water holding capacity, porosity, pH, and EC were analyzed. The changes in the physical properties of the greening substrate prepared from mud cake and stone waste are shown in the figure below. Figure 1 As shown.

[0069] Figure 1 The results show that soil bulk density refers to the mass of a unit volume of undisturbed soil after drying, and is generally used to reflect soil compaction and porosity. The suitable soil bulk density according to the second national soil survey in my country is 1.00–1.25 g / cm³. 3 CJ / T340-2016 "Green Planting Soil" requires a bulk density of <1.35 g / cm³. 3 When the ratio of mud cake to stone waste is 6:4 (G) or lower, the soil bulk density remains at 1.35 g / cm³. 3 the following.

[0070] Field holding capacity refers to the soil moisture content when the capillary suspended water reaches its maximum value. Capillary pores are primarily used for water storage and plant water utilization, which are directly related to soil porosity. Generally, soil field holding capacity ranges from 20% to 35%, and total soil porosity is between 45% and 55%. Experiments have shown that with optimized ratios of mud cake and stone waste (7:3 or 6:4), the field holding capacity of greening substrate soil is within a suitable range, and the capillary porosity is generally adjusted to around 50%. Figure 1 ).

[0071] 2) Chemical properties of greening substrates with different proportions

[0072] Soil pH is a key indicator for measuring soil acidity and alkalinity, effectively reflecting soil development and fertility levels. CJ / T 340-2016 "Greening Planting Soil" requires a pH range of 5.0–8.3. Therefore, except for treatments A and B, whose pH values ​​were below 5.0, all other treatments met the standard requirements. Soil electrical conductivity (EC) is the ion transport capacity of the soil solution and reflects soil salinity. According to CJ / T 340-2016 "Greening Planting Soil," the required soil EC value is 0.15–0.9 ms / cm. All treatments were far below 0.15 ms / cm, therefore, the addition of suitable environmental materials could be considered to improve the soil to a suitable salinity level. The results of the chemical index changes of the greening substrate prepared from mud cake and stone waste are shown in the figure below. Figure 2 As shown.

[0073] Depend on Figure 2 Based on CJ / T 340-2016 "Green Planting Soil" and CJJ 82-2012 "Code for Construction and Acceptance of Landscape Greening Engineering", the optimal ratio of mud cake and stone waste is 6:4 and 7:3. The 7:3 treatment results in better total porosity and capillary porosity of the greening substrate soil, while the 6:4 treatment has better pH and EC.

[0074] Investigation 2. Optimization Experiment of Soil Improvement Materials for Ecological Planting Soil Substrate

[0075] Experimental Setup: A four-factor, three-level orthogonal experiment was conducted. Different amounts of mineral-derived highly active potassium humate, cross-linked polymeric water-retaining materials, decomposed organic matter, and soil binder were mixed evenly and then applied to a substrate of mud cake and stone waste. Ecological planting soil was prepared according to the method in Example 1 as the soil-forming material. Each pot contained 500 g of soil, with three treatments per environmental material and three replicates per treatment. The soil was incubated indoors in the dark for 60 days. During the incubation period, water was applied every 2-3 days, with 50-60 mL of water each time. Samples were taken at 7, 25, and 60 days for analysis of physical indicators such as soil bulk density, field water holding capacity, and porosity. Chemical indicators such as pH, available nitrogen, available potassium, and available phosphorus were analyzed in the soil sample taken on day 25. Soil without added amendments served as a control (CK). Correlation analysis was used to explore the relationship between the three environmental materials and the various indicators of soil physicochemical properties. Principal component analysis was used to screen the optimal ratio of ecological planting soil matrix. The orthogonal experimental design table of the composite environmental materials including mineral-derived high-activity potassium humate, cross-linked polymer water-retaining material, decomposed organic matter, and soil binder in this invention is shown in Table 3. The preparation method of raw materials and the amount of other raw materials are the same as in Example 1.

[0076] Table 3 Orthogonal Experimental Design Table for Composite Environmental Materials

[0077]

[0078] The effects of the composite environmental materials of this invention on the physicochemical properties of ecological planting soil are shown in Tables 4 and 5 below.

[0079] Table 4. Effects of composite environmental materials on the physicochemical properties of ecological planting soil (1)

[0080]

[0081] Table 5. Effects of composite environmental materials on the physicochemical properties of ecological planting soil (2)

[0082]

[0083] As shown in Tables 4 and 5, (1) the effect of composite environmental materials on soil field water holding capacity: after 60 days of soil incubation, the A3 treatment group showed the best improvement in field water holding capacity, reaching 37.59%, which was 28.78% higher than the control group CK (29.19%); the A8 treatment group showed the worst improvement, with only 9.32% higher than the control group CK (29.19%). (2) After 60 days of soil incubation, the total porosity of the soil in the control group CK was 42.76%, and the total porosity of the soil in each treatment group ranged from 46.55% to 49.03%, with the A5 treatment group showing the most significant improvement. (3) The effect of composite environmental materials on soil bulk density was as follows: after 60 days of soil incubation, the soil bulk density of the control group CK was 1.40 g / cm3. The bulk density of the A1~A9 treatment groups all showed a decreasing trend compared with the control group CK, with a decrease range of 0.05 g / cm3~0.20 g / cm3. Among them, the A3 treatment group had the most significant effect on reducing the soil bulk density of the soil-forming materials of mud cake and stone waste. After 60 days of treatment, the soil bulk density decreased to 1.19 g / cm3. (4) After 60 days of soil incubation, the soil pH of the control group CK did not change significantly. After adding composite environmental materials, the soil pH of the soil-forming materials of the A1~A9 treatment groups was effectively improved. Among them, the treatment groups with better improvement effect were: A5 (pH=7.0), A7 (pH=6.9) and A9 (pH=9.8). (5) The soil electrical conductivity of the experimental groups treated with composite environmental materials was significantly higher than that of the control group CK, with an increase of 413.5 μs / cm to 1031.2 μs / cm. With the extension of the incubation time, the overall trend of soil electrical conductivity was a significant increase followed by a slight decrease. The treatment group with the most significant increase was the A3 treatment group (EC=1078.0 μs / cm). (6) The cation exchange capacity of the control group CK was only 0.11 cmol / kg. After 60 days of soil incubation with the addition of composite environmental materials, the increase in soil cation exchange capacity of each treatment group was 1.92 cmol / kg to 5.13 cmol / kg. The A7 treatment group showed the most significant increase, followed by A5 and A9. (7) The soil organic matter of the soil base treated with composite environmental materials was significantly improved compared with the control group CK, with an improvement range of 5.79 g / kg to 16.01 g / kg. The treatment groups that met the standard requirements after treatment were: A3 (15.1 g / kg), A4 (12.1 g / kg), A5 (16.5 g / kg), A7 (17.9 g / kg) and A9 (13.1 g / kg).(8) The available nitrogen content in the soil of the treatment groups improved by composite environmental materials was significantly higher than that of the control group CK. The available nitrogen content in the soil of each treatment group ranged from 76.4 mg / kg to 142.3 mg / kg. Among them, the A3 and A4 treatment groups showed the most significant increase, increasing by 111.0 mg / kg and 85.6 mg / kg respectively compared with CK. (9) After 60 days of soil incubation, the available phosphorus content in the soil of the soil-forming materials showed significant improvement in all treatment groups except for the A4, A5 and A6 treatment groups. Among them, the A1 treatment group showed the best improvement, increasing by 85.0 mg / kg compared with the control group CK, followed by the A9 treatment group (91.3 mg / g). (10) The available potassium content in the soil of the soil-forming materials after A1~A9 treatment ranged from 645 mg / kg to 1474 mg / kg compared with the control group CK. Among them, the A5 treatment group showed a particularly significant increase in available potassium, increasing the available potassium content in the soil to 1474.3 mg / kg.

[0084] The comprehensive evaluation and range analysis of the improvement effect of composite environmental materials in the preparation of ecological planting soil are shown in Tables 6-10 below.

[0085] Table 6. Effects of composite material addition on soil field water holding capacity and soil bulk density in ecological planting soil

[0086]

[0087] Table 6 shows that the improvement effects of each material on soil field capacity are as follows: decomposed organic matter (C) > mineral-derived highly active potassium humate (A) > soil binder (D) > cross-linked polymeric water-retaining material (B). Among these, the effect of mineral-derived highly active potassium humate on soil field capacity exhibits a negative dose-response relationship; treatment A1 maintains the field capacity at the optimal level. Decomposed organic matter, soil binder, and cross-linked polymeric water-retaining material all achieve the best improvement effect when added at the highest amounts (C3, D3, B3). Based on range analysis, the optimal ratio of the composite materials for improving soil field capacity is determined to be the A1B3C3D3 combination formula. According to the data analysis in Table 6, the improvement effects of each material on soil bulk density are as follows: decomposed organic matter (C) > mineral-derived highly active potassium humate (A) > soil binder (D) > cross-linked polymeric water-retaining material (B). Mineral-derived highly active potassium humate showed the optimal improvement in soil bulk density during treatment A3, while decomposed organic matter, soil binder, and cross-linked polymeric water-retaining materials achieved the best improvement effects during treatments C3, D2, and B2, respectively. Based on range analysis, the optimal ratio of composite materials for improving soil bulk density was determined to be the A3B2C3D2 combination formulation.

[0088] Table 7. Effects of composite material addition on soil organic matter and cation exchange capacity in ecological planting soil.

[0089]

[0090] Table 7 shows that the improvement effects of each material on soil organic matter are as follows: decomposed organic matter (C) > mineral-derived highly active potassium humate (A) > cross-linked polymeric water-retaining material (B) > soil binder (D). Soil organic matter content increases with increasing amounts of mineral-derived highly active potassium humate and decomposed organic matter; however, the organic matter content initially increases and then decreases with increasing amounts of cross-linked polymeric water-retaining material and soil binder. Therefore, the A3B2C3D2 ratio combination has the best improvement effect on increasing soil organic matter content. The influence of each material on soil cation exchange capacity is as follows: decomposed organic matter (C) > mineral-derived highly active potassium humate (A) > soil binder (D) > cross-linked polymeric water-retaining material (B). Among these, mineral-derived highly active potassium humate and decomposed organic matter achieve the best improvement effect on soil cation exchange capacity at the highest addition levels, while cross-linked polymeric water-retaining material and soil binder reach their optimal levels in treatments B2 and D2, respectively. Therefore, the A3B2C3D2 ratio combination has the best improvement effect on increasing soil cation exchange capacity.

[0091] Table 8. Effects of composite material addition on soil pH and soil electrical conductivity in ecological planting soil.

[0092]

[0093] Table 8 shows that the influence of each material on soil pH is as follows: decomposed organic matter (C) > soil binder (D) > mineral-derived highly active potassium humate (A) > cross-linked polymeric water-retaining material (B). The four amendments showed optimal levels in treatments A1, B3, C3, and D2, respectively. Therefore, the combination of A1B3C3D2 has the best effect on improving soil pH. Table 8 also shows that the influence of each material on soil electrical conductivity is as follows: mineral-derived highly active potassium humate (A) > soil binder (D) > cross-linked polymeric water-retaining material (B) > decomposed organic matter (C). Soil binder showed the best improvement effect at the highest addition level, while decomposed organic matter showed the best improvement effect at its lowest addition level. Mineral-derived highly active potassium humate and cross-linked polymeric water-retaining material reached optimal levels in treatments A2 and B2. Therefore, the combination of A2B2C1D3 has the best effect on improving soil electrical conductivity.

[0094] Table 9. Effects of composite material addition on the improvement of alkaline nitrogen and available phosphorus in ecological planting soil.

[0095]

[0096] Table 9 shows that the influence of each material on soil available nitrogen, in descending order, is: decomposed organic matter (C) > soil binder (D) > cross-linked polymeric water-retaining material (B) > mineral-derived highly active potassium humate (A). Among these, mineral-derived highly active potassium humate showed the best improvement effect at the lowest addition amount. However, with the increase of the amounts of cross-linked polymeric water-retaining material, decomposed organic matter, and soil binder, soil available nitrogen showed an upward trend, reaching its optimal level at the highest addition amounts of the three. Therefore, the A1B3C3D3 ratio was determined to be the optimal combination for improving soil available nitrogen. Table 9 also shows that the influence of each material on soil available phosphorus, in descending order, is: mineral-derived highly active potassium humate (A) > soil binder (D) > cross-linked polymeric water-retaining material (B) > decomposed organic matter (C). The effect of cross-linked polymeric water-retaining materials on improving available phosphorus in soil continuously increases with the increase of the addition amount, reaching the best improvement effect in treatment B3. Meanwhile, the three materials—mineral-derived highly active potassium humate, decomposed organic matter, and soil binder—all showed optimal levels at their minimum dosages (A1, C1, D1). Therefore, the combination of A1B3C1D1 was determined to be the optimal combination for improving available phosphorus in soil.

[0097] Table 10. The effect of adding composite materials on the improvement of available potassium in ecological planting soil.

[0098]

[0099] Table 10 shows that the influence of each material on available potassium in the soil is as follows: decomposed organic matter (C) > mineral-derived highly active potassium humate (A) > soil binder (D) > cross-linked polymeric water-retaining material (B). Among these, mineral-derived highly active potassium humate and cross-linked polymeric water-retaining material showed the best improvement effects in treatments A2 and B2, respectively. Meanwhile, decomposed organic matter and soil binder both showed optimal levels at their highest addition amounts. Therefore, the combination of A2B2C3D3 was determined to be the optimal combination for improving available potassium in the soil.

[0100] (Tables 6-10 above all conducted orthogonal experiments on composite environmental materials with four factors (A, B, C, D) and three levels (1, 2, 3). These experiments were range analyses. K1-3 represent the sum of experimental results for a certain factor at a certain level, and k1-3 represent the average value of experimental results for a certain factor at a certain level, i.e., k1 = K1 / 3. Taking the field capacity index as an example, for material A, K1 is the sum of the field capacity values ​​at all levels 1 in the orthogonal treatment, and k1 is the value obtained from K1 divided by 3, used to compare the advantages and disadvantages of each level.)

[0101] Principal component analysis

[0102] Principal component analysis was performed on the soil physicochemical properties of treatment groups A1–A9 using SPSS. The comprehensive score of each principal component was obtained by weighting each common factor. The results for mineral-derived highly active potassium humate (M), cross-linked polymeric water-retaining material (P), decomposed organic matter (N), and soil binder (B) are shown in Tables 11 and 12.

[0103] Table 11 Principal component analysis extraction results

[0104]

[0105] Table 12 Evaluation of the effect of composite environmental materials on improving ecological planting soil of mud cake and stone waste

[0106]

[0107] As shown in Tables 11 and 12, the A3 (M1P3N3B3) treatment group, obtained by principal component analysis, scored the highest in terms of the improvement effect of the ecological planting soil prepared from mud cake and stone waste. Specifically, 24 g of mineral-derived highly active potassium humate, 0.4 g of cross-linked polymer water-retaining material, 45 g of decomposed organic matter, and 1.8 g of soil binder were added to 1 kg of mud cake and stone waste (6:4 mixture).

[0108] Investigation 3. Planting Experiment with Ecological Planting Soil

[0109] Experimental setup

[0110] Based on soil culture simulation experiments, an optimized combination was selected: mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant, with a mass ratio of 33.5%:62.8%:0.6%:2.5%:0.7%. Five different application rates of the composite material (low, medium, and high) were set up, as shown in Table 6. The composite material was mixed evenly with a mixture of mud cake and stone waste, and then potted for the experiment (500 g per pot). A control group (CK) was set up with a mixture of mud cake and stone waste without the composite material. Each treatment was replicated three times. Considering the essential nutrients for plant growth, and based on the soil culture results, nitrogen, phosphorus, and potassium fertilizers were added. Nitrogen was applied in the form of urea at a rate of 0.2 g / kg, and phosphorus and potassium were added in the form of potassium dihydrogen phosphate at a rate of 0.36 g / kg. Planting was carried out after 14 days of culture. Select plump and uniform ryegrass seeds, sowing 40 seeds per pot. Sow the seeds evenly on the surface of the soil in each pot, then lightly cover with a thin layer of soil (approximately 0.5 cm to 1 cm). The planting time is 30-40 days. The harvested plants are then measured for relevant indicators. Remove the harvested ryegrass plants from the pots, wash them with clean water to remove soil from the roots, and then slowly rinse them with distilled water to remove impurities from the plant surface. The harvested ryegrass plants are separated into above-ground and underground parts. After air-drying the surface moisture, the plant height, above-ground fresh weight, root length, and underground fresh weight are measured. The plants are blanched in an oven at 105 ℃ for 30 minutes, then dried at 70 ℃ to constant weight and weighed to determine the above-ground and underground dry weights. Simultaneously, soil samples are collected from the pots, dried, and measured for soil pH, EC, and other indicators. The design table for the composite material usage in the pot planting experiment is shown in Table 13.

[0111] Table 13 Design table for composite material usage in potted plant experiment

[0112]

[0113] Results of plant cultivation experiment

[0114] (1) The effects of applying composite environmental materials at different dosage levels on the growth and development of the aboveground parts of ryegrass, such as Figure 3 As shown, by Figure 3 It was found that with increasing dosage levels, both the aboveground fresh weight and aboveground dry weight of ryegrass plants showed a trend of first increasing and then decreasing. After treatment, the aboveground fresh weight and dry weight of ryegrass ranged from 8.71 g to 13.61 g and 0.82 g to 1.40 g, respectively. All treatment groups showed an improvement compared to the control group (CK), with increases in aboveground fresh weight ranging from 5.26% to 56.28% and aboveground dry weight ranging from 31.98% to 70.04%. The S3 treatment group showed the best improvement, with aboveground fresh weight and dry weight of 13.61 g and 1.40 g, respectively.

[0115] (2) Effects of different dosage levels of composite environmental materials on the fresh and dry weight of ryegrass ground cover, such as Figure 4 As shown. By Figure 4 It can be seen that the treatment also has a certain improvement effect compared with the control group (CK). The fresh weight and dry weight of the ryegrass ground cover ranged from 1.25 g to 3.71 g and 0.76 g to 1.61 g, respectively. Among them, the S3 treatment group showed the most significant improvement effect, with the fresh weight of the ground cover increasing by 196.28% and the dry weight of the ground cover increasing by 111.35% compared with the CK treatment group.

[0116] (3) The plant height and root length of ryegrass after application of different amounts of compound environmental materials are as follows: Figure 5 As shown, the plant height of ryegrass exhibited a growth pattern of "slow increase followed by decrease," with each treatment group showing a promoting effect compared to the control group (CK). After low-dose treatment, the S1 and S2 treatment groups showed increases of 5.91% and 10.28% compared to the CK treatment group, respectively; after medium-dose treatment, the S3 treatment group showed an increase of 19.14% compared to the CK treatment group; and the high-dose treatment groups S4 and S5 showed increases of 12.42% and 4.07% compared to the CK treatment group, respectively.

[0117] (4) The pH of the soil used for planting plants was measured, and the effects of different treatments of the composite environmental materials on the pH of the ecological planting soil after planting were obtained as follows: Figure 6 .Depend on Figure 6 It can be seen that after different doses of composite materials were applied to ryegrass, the soil pH value of its ecological planting soil increased slowly with the increase of the environmental material dosage, and was significantly higher than that of the control group CK, increasing by 0.72, 0.84, 1.03, 1.05 and 1.07 respectively. Among them, the S5 treatment group had the best pH increase effect, with the pH increasing to 7.17.

[0118] (5) The effect of different treatments of composite environmental materials on the electrical conductivity of ecological planting soil after planting is shown in the figure. Figure 7 As shown. By Figure 7 It can be seen that the soil electrical conductivity of the ecological planting soil formed by mud cake and stone waste significantly increased with the increase of environmental material dosage, with an increase range of 513.7~1400.37 μs / cm. The low dosage treatment groups S1 and S2 increased by 373.24% and 576.68% respectively compared with the control group CK; the medium dosage treatment group S3 increased by 892.7 μs / cm compared with CK; and the high dosage treatment groups S4 and S5 increased by 1238.37 μs / cm and 1400.37 μs / cm respectively compared with CK.

[0119] (5) Results of the effects of different treatments of composite environmental materials on the cation exchange capacity of ecological planting soil after plant planting are as follows: Figure 8As shown. By Figure 8 It was found that the application of different doses of composite environmental materials significantly improved the cation exchange capacity of ecological planting soil, with the improvement range ranging from 0.89 to 3.40 cmol / kg. Compared with the control group (CK), the treatment groups showed increases of 280.89%, 514.40%, 847.75%, 1045.73%, and 1071.11%, respectively.

[0120] (7) The changing trends of organic matter in ecological planting soil after planting ryegrass with different treatment composite environmental materials are as follows: Figure 9 As shown, the levels exhibit a continuous upward trend. Compared to the control group CK, S1~S5 increased by 6.84, 11.03, 14.64, 15.68, and 20.15 g / kg, respectively. The S5 treatment group showed the best improvement, with soil organic matter in the soil-forming material increasing to 23.86 g / kg.

[0121] (8) Changes in the contents of available nitrogen, available phosphorus, and available potassium in ecological planting soils under different treatments after planting are as follows: Figure 10 As shown, alkaline available nitrogen exhibits a continuous increasing trend with the increase of environmental materials added, generally showing an "N"-shaped growth pattern. Specifically, the S1-S5 treatment groups showed increases of 3.0 mg / kg, 15.3 mg / kg, 28.7 mg / kg, 42.3 mg / kg, and 43 mg / kg compared to the CK control group, respectively. The available phosphorus content in all treatment groups of the ecological planting soil showed a significant increase compared to the CK control group, ranging from 25.96 mg / kg to 75.30 mg / kg. Compared to the CK control group, the available potassium content in all S1-S5 treatment groups was significantly increased, with S5 showing the largest increase of 1573.0 mg / kg, and S1 showing the smallest increase, rising from 136.0 mg / kg in the CK treatment group to 699.7 mg / kg.

[0122] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ecological planting soil that recycles stone waste and mud cake, characterized in that, It is prepared from the following raw materials: 30-40 parts stone waste, 60-70 parts mud cake, and 6-8 parts soil conditioner; The soil conditioner is composed of mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant; the mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound inoculant is (28~38):(52~70):(0.2~1.0):(1~4.5):(0.2~1.2).

2. The ecological planting soil according to claim 1, characterized in that, The mass ratio of the stone waste residue to the mud cake is (4~3):(6~7).

3. The ecological planting soil according to claim 1, characterized in that, The mass ratio of the mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining material, soil binder, and soil microbial compound agent is (30~35):(58~65):(0.4~0.8):(1~5.5):(0.4~1.0).

4. The ecological planting soil according to claim 1, characterized in that, The method for preparing the mineral-derived highly active potassium humate includes the following steps: mixing nitric acid solution and weathered coal, and then oxidizing the mixture to obtain highly active weathered coal; mixing the highly active weathered coal with KOH solution, and then subjecting the mixture to alkali treatment to adjust the pH to obtain mineral-derived highly active potassium humate.

5. The ecological planting soil according to claim 1, characterized in that, The cross-linked polymeric water-retaining material is anionic polyacrylamide (APAM); the molecular weight of the cross-linked polymeric water-retaining material is 1,000,000 to 1,200,000 Daltons.

6. The ecological planting soil according to claim 1, characterized in that, The method for preparing the decomposed organic matter includes the following steps: mixing weathered coal, cow dung, corn stalks and compound microorganisms, and then fermenting and decomposing them to obtain decomposed organic matter.

7. The ecological planting soil according to claim 6, characterized in that, The total raw materials, consisting of weathered coal, cow dung, and corn stalks, have a carbon-to-nitrogen ratio of (26-30):1; the fermentation temperature is 35-60℃; the fermentation time is 150-200 hours; during the fermentation process, the moisture content of the fermentation system is maintained at 45wt%-49wt%; and air is introduced into the fermentation system at a flow rate of 0.15 L / min.

8. The ecological planting soil according to claim 1, characterized in that, The soil binder is a ferrous sulfate binder with a purity of ≥90% and an iron content of ≥18.1%.

9. The ecological planting soil according to claim 1, characterized in that, The soil microbial compound inoculant is composed of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis; the mass ratio of Bacillus subtilis, Bacillus megaterium, silicate bacteria, and Bacillus licheniformis is 1:0.5:0.3:0.

5.

10. A method for preparing the ecological planting soil according to any one of claims 1 to 9, characterized in that, Includes the following steps: A soil conditioner is obtained by mixing mineral-derived highly active potassium humate, decomposed organic matter, cross-linked polymer water-retaining materials, soil binders, and soil microbial compound inoculants. After mixing stone waste, mud cake and soil conditioner, the mixture is aged to obtain ecological planting soil that recycles stone waste and mud cake.

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