A method for improving abandoned slag based on water-retaining material combined with aspergillus niger

Abstract

This invention discloses a method for improving waste slag based on water-retaining materials combined with Aspergillus niger, belonging to the field of mine ecological restoration and soil improvement technology. This invention restores the soil characteristics of waste slag by adding organic fertilizer, straw powder, humic acid, and a mixed microbial agent, enhancing soil microbial activity, promoting organic matter decomposition and nutrient transformation, thereby releasing available nutrients for plants. Adding Aspergillus niger spore powder transforms inorganic minerals in the waste slag that are difficult to utilize into forms that can be absorbed by plants, improving nutrient bioavailability and further improving the rhizosphere environment. Adding water-retaining polymers enhances the water-holding capacity of the substrate, alleviates drought stress, improves pore structure, prevents excessive water loss, and provides a stable water supply for plants. Ultimately, the physicochemical properties and biological activity of the waste slag are significantly improved, gradually transforming it into a substrate suitable for plant growth, thereby achieving ecological restoration and vegetation reconstruction of mine slopes.

Description

Technical Field

[0001] This invention belongs to the field of mine ecological restoration and soil improvement technology, and in particular relates to a method for improving waste residue based on water-retaining materials combined with Aspergillus niger. Background Technology

[0002] Xinjiang Uygur Autonomous Region, as an important iron ore resource base, has more than 300 iron ore deposits, including 37 large and medium-sized deposits. While large-scale iron ore mining and beneficiation provide resources, they also generate massive amounts of solid waste—slag. The indiscriminate dumping of this slag occupies vast amounts of land, and its fine particles are easily stirred up by dust during dry and windy weather, exacerbating soil desertification and salinization in the surrounding areas. More importantly, the slag itself possesses a series of unfavorable physical and chemical properties: extremely low nutrient content, loose and unstable structure, uneven particle composition, and extremely poor water and fertilizer retention capacity; the surface is prone to compaction, hindering root penetration and water infiltration. These characteristics severely impede the natural restoration process of the mining area's ecosystem and pose a long-term threat to agricultural and pastoral production and the ecological environment downstream of the slag dump.

[0003] Furthermore, Xinjiang's typical arid and semi-arid continental climate makes the aforementioned ecological restoration tasks exceptionally challenging. The region generally experiences scarce rainfall, intense evaporation, cold winters, and frequent sandstorms. Under these extreme conditions, the restoration substrate evaporates moisture rapidly and suffers severe nutrient loss, requiring planted plants to possess extremely strong drought, cold, poor soil, and salinity tolerance. Therefore, the resource utilization and ecological restoration of waste materials must not only address their inherent pollution and structural problems but also overcome the enormous challenge of the extreme climatic conditions that exponentially increase the difficulty of plant establishment and community reconstruction.

[0004] Although numerous practices have been implemented in the ecological restoration of open-pit mines in the arid and cold regions of Xinjiang, a comprehensive waste disposal technology system that can simultaneously achieve the goals of efficiency, environmental protection, and economic benefits is still in its initial exploratory stage. Therefore, given the massive amounts of waste generated by the continued development of resource bases such as iron ore belts, there is an urgent need to develop a more targeted, lower-cost, and more sustainable localized remediation technology. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a waste residue improvement method based on water-retaining materials combined with Aspergillus niger.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for improving waste residue based on water-retaining materials combined with Aspergillus niger, comprising the following steps: Using waste residue as the main material and nutrient soil, Aspergillus niger spore powder, water-retaining polymer, organic fertilizer, straw powder, humic acid and microbial mixed inoculant as auxiliary materials, the main material and auxiliary materials are mixed to obtain a planting substrate; herbaceous plants are planted on the planting substrate to achieve ecological restoration and soil reconstruction of waste residue.

[0007] Furthermore, based on a total mass of 1000g for the waste residue and nutrient soil, the amount of the water-retaining polymer used is 30g.

[0008] Furthermore, the concentration of the water-retaining polymer is 0.1~1.0%.

[0009] Furthermore, based on a total mass of 1000g for the waste residue and nutrient soil, the amount of organic fertilizer used is 30g, the amount of straw powder used is 30g, the amount of humic acid used is 10g, and the amount of mixed microbial agent used is 10g.

[0010] Furthermore, the mass ratio of the waste residue to the nutrient soil is (10:0) to (7:3).

[0011] Furthermore, the microbial mixed inoculant is a mixture of Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus in a mass ratio of 1:1:4.

[0012] Furthermore, based on a total mass of 1000g for the waste residue and nutrient soil, the amount of Aspergillus niger spore powder added is 1.5~2.5g.

[0013] Furthermore, the particle size of the waste residue is ≤2mm; the particle size of the nutrient soil is ≤2mm.

[0014] This invention provides an application of the waste residue improvement method based on water-retaining materials combined with Aspergillus niger as described above in the ecological restoration of mining areas in Xinjiang.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: Waste residue has a loose structure, is nutrient-poor, and has a water-holding and fertilizer-retention capacity far lower than soil. Furthermore, its irregular particle size and lack of essential plant nutrients (nitrogen, phosphorus, potassium, etc.) hinder plant growth. However, it possesses some soil characteristics. This invention further restores the soil properties of the waste residue by adding organic fertilizer, straw powder, humic acid, and mixed microbial agents, enhancing soil microbial activity, promoting organic matter decomposition and nutrient transformation, thereby releasing available nutrients for plant use, improving soil fertility, and creating favorable conditions for vegetation restoration. Secondly, the addition of Aspergillus niger spore powder, through the organic acids and extracellular enzymes secreted by Aspergillus niger and other microorganisms, transforms the inorganic minerals in the waste residue that are difficult to utilize into forms that can be absorbed by plants, improving nutrient bioavailability and further improving the rhizosphere environment. Finally, the addition of water-retaining polymers significantly enhances the water-holding capacity of the substrate, alleviates drought stress, improves pore structure, prevents excessive water loss, and provides a stable water supply for plants. Through the above comprehensive improvement measures, the physical and chemical properties and biological activity of the waste slag have been significantly improved, and it has been gradually transformed into a substrate suitable for plant growth, thereby realizing the ecological restoration and vegetation reconstruction of the mining area slope.

[0016] This invention, through the combined use of water-retaining polymers, Aspergillus niger spore powder, and organic fertilizer, can significantly improve the soil structure, water retention capacity, and nutrient availability of waste slag, promote plant growth, and optimize the rhizosphere microbial community. This invention confirms that waste slag, after modification, can be utilized as a plant growth substrate for resource recovery, providing a feasible technical approach and theoretical support for the ecological restoration and vegetation reconstruction of iron ore waste slag in arid and cold regions. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The effects of 12 treatment groups and 3 control groups in Example 1 on the growth and development of alfalfa are shown, where (a) is plant height and (b) is root length. Figure 2 The effects of 12 treatment groups and 3 control groups in Example 1 on soil physicochemical properties are shown. (a) represents soil moisture content, (b) represents total nitrogen, (c) represents ammonia nitrogen, (d) represents nitrate nitrogen, (e) represents organic carbon, (f) represents total phosphorus, (g) represents available phosphorus, and (h) represents available potassium. Figure 3 The effects of 12 treatment groups and 3 control groups in Example 1 on soil enzyme activity are shown. Among them, (a) is catalase, (b) is urease, (c) is alkaline protease, and (d) is sucrase. Figure 4 The soil bacterial community composition is the same as that of the 12 treatment groups and 3 control groups in Example 1; Figure 5 The soil fungal community composition of the 12 treatment groups and 3 control groups in Example 1; Figure 6 This is an analysis of microbial alpha diversity in the 12 treatment groups and 3 control groups in Example 1; Figure 7 Differential bacterial metabolic pathways in the 12 treatment groups and 3 control groups in Example 1, based on the MetaCyc database; Figure 8 Differential metabolic pathways of fungi in 12 treatment groups and 3 control groups in Example 1, based on the MetaCyc database; Figure 9 The results of the correlation analysis of environmental factors in the 12 treatment groups and 3 control groups in Example 1 are shown. Among them, (a) shows the correlation between bacterial community and soil environmental factors, and (b) shows the correlation between fungal community and soil environmental factors. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] This invention provides a method for improving waste residue based on water-retaining materials combined with Aspergillus niger, comprising the following steps: Using waste residue as the main material and nutrient soil, Aspergillus niger spore powder, water-retaining polymer, organic fertilizer, straw powder, humic acid and microbial mixed inoculant as auxiliary materials, the main material and auxiliary materials are mixed to obtain a planting substrate; herbaceous plants are planted on the planting substrate to achieve ecological restoration and soil reconstruction of waste residue.

[0021] In a preferred embodiment, based on a total mass of 1000g for the waste residue and nutrient soil, the amount of the water-retaining polymer used is 30g.

[0022] In a preferred embodiment, the concentration of the water-retaining polymer is 0.1~1.0%, more preferably 1.0%; the water-retaining polymer is SJP; the preparation method of the SJP refers to patent CN119528516A, which has a good three-dimensional network structure, and can significantly improve the water holding capacity and water regulation performance of the substrate after absorbing water, while improving the pore structure of the substrate and enhancing the aggregation stability, thus creating a more suitable microenvironment for plant roots.

[0023] In a preferred embodiment, the particle size of the waste residue is ≤2mm; the waste residue is further preferably tailings, slag, or tailings slag. Tailings are fine-particle solid waste discharged from the Awulale Iron Mine in the Western Tianshan Mountains of Xinjiang after the ore beneficiation process. The process involves the following steps: after the iron ore is mined, it undergoes crushing, grinding, magnetic separation, or flotation to extract the iron concentrate, leaving behind fine-grained mineral residue with low iron content. Slag is a mixture of ore-free waste rock and topsoil generated during the mining process at the Awulale Iron Mine in the Western Tianshan Mountains of Xinjiang, involving topsoil stripping, rock crushing, and tunnel excavation to expose the ore body. It typically contains larger-sized rock fragments, clay minerals, and some organic matter. Tailings slag is waste residue from the Songhu Iron Mine in Nileke County, Xinjiang.

[0024] In a preferred embodiment, the mass ratio of the waste residue to the nutrient soil is (10:0) to (7:3), more preferably 10:0. A mass ratio of waste residue to nutrient soil of 10:0 indicates that the planting substrate prepared using only waste residue will also result in good crop growth even without the addition of nutrient soil.

[0025] In a preferred embodiment, the particle size of the nutrient soil is ≤2mm; the nutrient soil was purchased from Weifang Lanbao Intelligent Technology Co., Ltd.

[0026] In a preferred embodiment, based on a total mass of 1000g for the waste residue and nutrient soil, the amount of organic fertilizer used is 30g, the amount of straw powder used is 30g, the amount of humic acid used is 10g, and the amount of mixed microbial agent used is 10g.

[0027] In a preferred embodiment, the organic fertilizer is used after passing through a 2mm sieve; the organic fertilizer is purchased from Weifang Lanbao Intelligent Technology Co., Ltd.

[0028] In a preferred embodiment, the microbial mixed inoculant is a mixture of Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus in a mass ratio of 1:1:4. This invention utilizes a microbial mixed inoculant composed of Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus. These strains possess the ability to fix nitrogen, solubilize phosphorus, release potassium, and secrete growth-promoting substances, which can synergistically improve soil nutrient supply, inhibit soil-borne diseases, and stimulate plant growth.

[0029] In a preferred embodiment, based on a total mass of 1000g of the waste residue and nutrient soil, the amount of Aspergillus niger spore powder added is 1.5~2.5g, more preferably 2.0g. The Aspergillus niger spore powder used in this invention is derived from Aspergillus niger mycelium, which is rich in active spores and various extracellular enzyme systems. After application, Aspergillus niger effectively decomposes organic matter and activates fixed mineral nutrients such as phosphorus and potassium in tailings by secreting metabolic products such as organic acids and proteases, and can participate in the transformation of heavy metal speciation, thereby improving rhizosphere nutrient cycling and bioavailability.

[0030] In a preferred embodiment, the herbaceous plant is selected from one or more of crested wheatgrass, tall fescue, ryegrass, and alfalfa.

[0031] This invention provides an application of the waste residue improvement method based on water-retaining materials combined with Aspergillus niger as described above in the ecological restoration of mining areas in Xinjiang.

[0032] In a preferred embodiment, the Xinjiang mining area includes waste dumping areas in arid and semi-arid regions such as Xinjiang.

[0033] In this embodiment of the invention, room temperature refers to "25±2℃".

[0034] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0035] Example 1 The experiment was conducted for 60 days in a greenhouse at a temperature of 20-30℃ and a humidity of 50-80%. Twenty-five alfalfa seeds were artificially sown in each pot (15.5 cm in diameter and 10.5 cm in height). The alfalfa seeds were disinfected with 10% hydrogen peroxide for 10 minutes before sowing, and then rinsed with deionized water. To maintain normal plant growth, the plants were watered with 100 mL of water every 3 days. No additional fertilizer was applied during the growing season. Each group had three replicates, resulting in 12 treatment groups and 3 control groups.

[0036] The planting substrate used was a mixture of waste residue, nutrient soil, organic fertilizer, straw powder, humic acid, mixed microbial inoculant, Aspergillus niger spore powder, and water-retaining material SJP. Twelve treatment groups were designed based on four factors: the ratio of slag to nutrient soil (mass ratio of slag to nutrient soil, 1:0, 9:1, 7:3), the type of waste residue (tailings, slag soil, tailings residue), the concentration of SJP (0%, 0.8%, 1%), and the amount of Aspergillus niger spore powder added (1.5g, 2.0g, 2.5g). Specific experimental groups are shown in Table 1. Three control groups were set up. All treatment groups and control groups were uniformly supplemented with 30g of organic fertilizer, 30g of straw powder, 10g of humic acid, and 10g of mixed microbial agent (Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus in a mass ratio of 1:1:4). The total mass of slag and nutrient soil was 1000g. After mixing, the mixture was potted for planting experiment. The particle size of the waste slag was ≤2mm. The particle size of the nutrient soil was ≤2mm. The organic fertilizer was purchased from Weifang Lanbao Intelligent Technology Co., Ltd. and used after passing through a 2mm sieve.

[0037] Table 1 Experimental Groups Test results 1. Plant growth Plant height: Measure 10-15 alfalfa plants according to the five-point sampling method and record the average value; Plant root length: The roots of the selected plants are completely removed, and the average value is measured and recorded.

[0038] Figure 1 The effects of 12 treatment groups and 3 control groups in Example 1 on the growth and development of alfalfa are shown. (a) represents plant height, and (b) represents root length. Data are presented as mean ± standard deviation of three replicates. Different lowercase letters indicate significant differences (p < 0.05), and the same applies below. Figure 1 As shown in section (a), when the waste type was slag, the plant height of group A1B2 was the highest among the groups, significantly higher than the other treatment groups and the control group (p<0.05); when the waste type was tailings, the plant height of group A3B1 was the highest among the groups, increasing by 69.47% compared to the control group; when the waste type was tailings, the plant height of group A3B3 was the highest among the groups, increasing by 129.41% compared to the control group; among all treatments and the control group, group A1B2 had the highest plant height, significantly increasing by 166.67% compared to the slag control group (CK2) (p<0.05). From Figure 1As shown in section (b), the root length of each treatment group was significantly higher than that of the control group (p < 0.05). When the waste type was tailings, the root length of group A2B1 was the longest, increasing by 281.19% compared to the control group; when the waste type was tailings, the root length of group A1B3 was the longest, increasing by 132.35% compared to the control group; when the waste type was slag, the root length of group A1B2 was significantly higher (p < 0.05), increasing by 253.72% compared to the control group. In summary, the plant height and root length of group A1B2 (slag-to-slag ratio of 1:0, SJP concentration of 1%, and Aspergillus niger spore powder addition of 2.0g) were the best among all treatment groups. It is possible that SJP improves soil properties, increases soil cohesion, improves aeration, and provides a better growth environment for plant roots; Aspergillus niger can produce a variety of substances that may change the soil microenvironment and may reduce heavy metal toxicity; at this ratio, the synergistic effect of the improvement is better, significantly improving the microenvironment of pure waste residue, thereby promoting plant growth.

[0039] 2. Soil physicochemical properties Soil total phosphorus was determined using the sulfuric acid digestion-molybdenum antimony method (Chapter 10 of the Handbook of Soil Agrochemical Analysis); soil available phosphorus was determined using the sodium bicarbonate extraction-molybdenum antimony spectrophotometric method (HJ 704-2014); soil available potassium was determined using a flame atomic emission spectrophotometer (NY / T 889-2004); soil nitrate nitrogen was determined using ultraviolet spectrophotometry (GB / T 32737-2016); soil ammonia nitrogen was determined using the sodium salicylate-spectrophotometric method (HJ 634-2012); soil total nitrogen was determined using the sulfuric acid digestion-sodium salicylate method (Chapter 9 of the Handbook of Soil Agrochemical Analysis); and soil organic carbon was determined using the potassium dichromate oxidation-spectrophotometric method (HJ615-2011).

[0040] Figure 2 The effects of 12 treatment groups and 3 control groups in Example 1 on soil physicochemical properties are shown, where (a) is soil moisture content, (b) is total nitrogen, (c) is ammoniacal nitrogen, (d) is nitrate nitrogen, (e) is organic carbon, (f) is total phosphorus, (g) is available phosphorus, and (h) is available potassium. Figure 2 As can be seen in Part (a), except for Group A1B2, the soil moisture content of each treatment group was significantly higher than that of the control group (p<0.05), indicating that SJP and Aspergillus niger can indeed improve the soil water holding capacity.

[0041] Soil nutrient content not only reflects soil fertility but also directly or indirectly affects plant nutrient absorption and growth, playing a crucial role in waste improvement and plant growth. For example... Figure 2As shown in section (b), groups A2B1, A1B2, and A1B3 showed significantly higher TN content (p < 0.05) in their respective tailings types, with group A2B1 (using tailings) exhibiting the highest TN content (p < 0.05), which was 20.36 times that of the control group CK1. Figure 2 As shown in sections (c) and (d), the nitrate nitrogen and ammonia nitrogen contents of groups A3B1 and A1B2 were significantly higher (p < 0.05) than those of the other groups. Specifically, the ammonia nitrogen content of group A1B2, which used slag soil, was 2.78 times higher than that of CK2, while the nitrate nitrogen content of group A3B1, which used tailings, was 19.85 times higher than that of CK1. Figure 2 As shown in section (f), the total phosphorus content of tailings group A3B1 and tailings group A3B2 showed the greatest increase compared to the control group; as Figure 2 As shown in section (g), the AP (available phosphorus) content of most treatment groups was significantly increased (p < 0.05), with the A3B3 group using tailings showing the largest increase in AP content (p < 0.05), which was 2.67 times higher than that of CK3; Figure 2 As shown in section (h), except for group A1B3, all treatment groups showed a significant increase in available potassium in the soil compared to the control group CK (p < 0.05). Among them, group A3B2, which used slag soil, showed the highest significance (p < 0.05), which was 1.58 times that of the corresponding control group CK2.

[0042] Figure 2 The experimental results may be because the addition of SJP improved soil structure, promoted soil nutrient cycling, and increased nutrient availability; Aspergillus niger is also a common soil microorganism that secretes a variety of organic acids and participates in soil nutrient cycling; the addition of SJP may have provided a better growth environment and microecology for Aspergillus niger, and combined with the better synergistic effect of the slag-soil ratio, it can enhance soil nutrients and promote plant growth.

[0043] 3. Soil enzyme activity Sucrase, alkaline protease, catalase, and urease were all measured using an enzyme-linked immunosorbent assay (ELISA) kit manufactured by Suzhou Keming Biotechnology Co., Ltd.

[0044] Soil enzyme activity participates in the biogeochemical cycle of various elements in the soil and plays a direct or indirect role in plant growth.

[0045] Figure 3 The effects of 12 treatment groups and 3 control groups in Example 1 on soil enzyme activity are shown, where (a) is catalase, (b) is urease, (c) is alkaline protease, and (d) is sucrase. Figure 3As shown in section (a), the catalase activity of the tailings group as a whole was relatively higher. The enzyme activities of groups A3B1 and A3B3 were significantly higher than those of the corresponding control group (p < 0.05), with the catalase activity of group A3B3 being 1.21 times that of the control group. Figure 3 As shown in section (b), most treatment groups showed a significant increase in urease activity compared to the control group (p < 0.05), with the most significant increases observed in groups A2B1, A2B2, and A1B3. Figure 3 As shown in section (c), the alkaline protease activity was highest in group CK3 (p < 0.05), while the alkaline protease activities in groups A1B1 and A2B1 were significantly higher than those in CK1 (p < 0.05). Figure 3 As shown in section (d), the sucrase activity in the tailings group was relatively low, but it was still higher than that in the control group. This increase in enzyme activity may be because *Aspergillus niger* itself can secrete various extracellular enzymes such as amylase and protease. Furthermore, as mentioned earlier, different tailings-to-soil ratios and the addition of SJP and *Aspergillus niger* can promote nutrient cycling in the soil microenvironment, and increased biological metabolic activity is also beneficial for enzyme production. Conversely, enhanced soil enzyme activity will also promote biological metabolic activity, soil nutrient cycling, and plant growth.

[0046] 4. Soil microbial diversity and community structure Soil microbial diversity and community structure: 5.0 g of soil was weighed for each sample, placed in a foam box with dry ice, and rapidly transported to the analytical laboratory for PCR amplification. Sequencing was then performed using the Illumina MiSeq high-throughput sequencing platform. Results are shown below. Figures 4-8 .

[0047] Figure 4 The soil bacterial community composition is the same as that of the 12 treatment groups and 3 control groups in Example 1. Figure 4 The results showed that although the components and densities of the different treatment groups were not exactly the same, the main composition was similar, and the dominant bacterial phyla included Pseudomonadota, Bacillota, and Bacteroidota.

[0048] Figure 5 The soil fungal community composition is the same as that of the 12 treatment groups and 3 control groups in Example 1. Figure 5The results showed that the dominant fungal phyla in each treatment group included Ascomycota, one unclassified fungus, and Basidiomycota. These phyla collectively acted as the dominant microenvironmental species, promoting soil nutrient cycling and plant growth through multiple mechanisms. The addition of SJP and Aspergillus niger spore powder, combined with different soil-to-soil ratios, resulted in a rapid response of the soil microbial community to external environmental influences, accompanied by changes in microbial function. These changes altered soil nutrients through assimilation or dissimilation processes. For example, Pseudomonas and Bacillus secreted organic acids and enzymes to convert insoluble phosphorus and potassium compounds in the soil into soluble forms, improving nutrient utilization efficiency and thus promoting plant growth. The mycelia produced by Ascomycota and Basidiomycota, as well as the extracellular polysaccharides secreted by bacteria, helped form stable soil aggregates, improving soil pore structure, increasing soil water retention and aeration, and providing a better growth environment for plant roots.

[0049] Figure 6 This study analyzed the microbial alpha diversity of the 12 treatment groups and 3 control groups in Example 1. Figure 6 The results showed that the species richness of bacteria in the treatment groups was reduced to varying degrees compared with the control group. The dominant species levels and diversity of bacteria in groups A2 and A3B3 were higher than those in the control group. The fungal richness in groups A2B2 and A2B3 was higher than that in the control group. Most treatment groups showed increased fungal diversity and dominant species levels. This may be because soil improvement makes it more suitable for the colonization and survival of dominant species such as Pseudomonas, Bacillus, and Ascomycetes, attracting other species to colonize and increasing species diversity, thus promoting more comprehensive nutrient cycling in the soil.

[0050] Figure 7 The differential metabolic pathways of bacteria in the 12 treatment groups and 3 control groups in Example 1 are based on the MetaCyc database. Figure 7 The results showed that the functional prediction of bacteria mainly focused on processes such as amino acid biosynthesis and coenzyme synthesis. The abundance of the overall pathway was low, while the activity of some processes, such as L-lysine biosynthesis and UMP biosynthesis, was significantly higher (p<0.05).

[0051] Figure 8 The differential fungal metabolic pathways in the 12 treatment groups and 3 control groups in Example 1 are based on the MetaCyc database. Figure 8The results showed that fungi are mainly involved in basic metabolic processes such as tRNA binding to amino acids, protein synthesis, glycolysis pathways, and amino acid biosynthesis. The enhancement of these functional pathways is the reason for the increase in soil nutrient content. For example, amino acid biosynthesis promotes nitrogen fixation and storage; microorganisms enhance the activity of glycolysis pathways through coenzyme synthesis; glycolysis intermediates (such as phosphoenolpyruvate) can serve as precursors to promote amino acid synthesis, forming a carbon-nitrogen co-cycle; and Bacillus and other fungi can also directly promote plant growth by synthesizing auxin (IAA) and ACC deaminase.

[0052] 5. Comprehensive score of environmental factors The correlation between various environmental factors (soil enzyme activity and soil nutrients) and changes in microbial communities under different treatments was analyzed, and the results are shown in [the table below]. Figure 9 In the diagram: N-NO3 - Represents nitrate nitrogen; N-NH4 + The symbols represent: ammoniacal nitrogen; AP represents available phosphorus; TOC represents organic carbon; TN represents total nitrogen; TP represents total phosphorus; AK represents available potassium; UE represents soil urease activity; S-ALPT represents soil alkaline protease activity; S-SC represents soil sucrase activity; S-CAT represents soil catalase activity; asterisks indicate significance. This means 0.01 < p ≤ 0.05. This means 0.001 < p ≤ 0.01. This means p ≤ 0.001.

[0053] Figure 9 The results of the environmental factor correlation analysis for the 12 treatment groups and 3 control groups in Example 1 are shown, where (a) shows the correlation between bacterial community and soil environmental factors, and (b) shows the correlation between fungal community and soil environmental factors. Figure 9 As shown in section (a), TN is strongly positively correlated with TP, and TN is significantly associated with S-CAT and UE, reflecting the synergistic effect of nitrogen and phosphorus cycling and microbial metabolism. This may be because changes in NP nutrients affect soil enzyme activity, thereby regulating changes in the microbial community. The negative correlation between AK and TOC may indicate the unique regulatory role of potassium content in carbon metabolism. Figure 9 As shown in section (b), the negative correlation between AP and S-ALPT is significantly enhanced, reflecting that available phosphorus may have some inhibitory effect on phosphatases under environmental changes. The correlation between various enzymes also reflects the response of the microbial community to changes in environmental factors.

[0054] The changes in soil environmental factors after different treatments were weighted using the entropy method, and the comprehensive scores are shown in Table 2.

[0055] Table 2 Comprehensive Score of Soil Environmental Factor Changes Table 2 shows that among all the positive indicators required for plant growth, group A1B2 (slag-to-soil ratio of 1:0, SJP concentration of 1%, and Aspergillus niger spore powder addition of 2.0g) scored the highest, perfectly explaining the phenomenon of optimal plant growth under this treatment group. The difference in the test results further confirms that the change in environmental conditions reshapes the correlation network between soil factors. This change in network structure directly affects the efficiency of soil nutrient cycling and the stability of biological functions.

[0056] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving waste residue based on water-retaining materials combined with Aspergillus niger, characterized in that, Includes the following steps: Using waste residue as the main material and nutrient soil, Aspergillus niger spore powder, water-retaining polymer, organic fertilizer, straw powder, humic acid and microbial mixed inoculant as auxiliary materials, the main material and auxiliary materials are mixed to obtain a planting substrate; herbaceous plants are planted on the planting substrate to achieve ecological restoration and soil reconstruction of waste residue.

2. The waste residue improvement method based on water-retaining materials combined with Aspergillus niger according to claim 1, characterized in that, Based on a total mass of 1000g for the waste residue and nutrient soil, the amount of the water-retaining polymer used is 30g.

3. The waste residue improvement method based on water-retaining materials combined with Aspergillus niger according to claim 1, characterized in that, The concentration of the water-retaining polymer is 0.1~1.0%.

4. The waste residue improvement method based on water-retaining materials combined with Aspergillus niger according to claim 1, characterized in that, Based on a total mass of 1000g for the waste residue and nutrient soil, the amount of organic fertilizer used is 30g, the amount of straw powder used is 30g, the amount of humic acid used is 10g, and the amount of mixed microbial agent used is 10g.

5. The waste residue improvement method based on water-retaining materials combined with Aspergillus niger according to claim 1, characterized in that, The mass ratio of the waste residue to the nutrient soil is (10:0) to (7:3).

6. The waste residue improvement method based on water-retaining materials combined with Aspergillus niger according to claim 1, characterized in that, The microbial mixed inoculant is a mixture of Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus in a mass ratio of 1:1:

4.

7. The waste residue improvement method based on water-retaining materials combined with Aspergillus niger according to claim 1, characterized in that, Based on a total mass of 1000g for the waste residue and nutrient soil, the amount of Aspergillus niger spore powder added is 1.5~2.5g.

8. The waste residue improvement method based on water-retaining materials combined with Aspergillus niger according to claim 1, characterized in that, The particle size of the waste residue is ≤2mm; the particle size of the nutrient soil is ≤2mm.

9. The application of a waste residue improvement method based on water-retaining materials combined with Aspergillus niger as described in any one of claims 1 to 8 in the ecological restoration of mining areas in Xinjiang.

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