A method for soilizing engineering residue soil based on water-fertilizer organic matter-sugarcane cooperation

Abstract

This invention provides a method for soilification of engineering waste soil based on the synergistic effect of water, fertilizer, organic matter, and sugarcane, belonging to the field of soil improvement and ecological restoration technology. The method includes the following steps: Step 1, cultivating sugarcane seedlings; Step 2, transplanting sugarcane seedlings; Step 3, dynamic gradient water and fertilizer management. This invention utilizes a sugarcane-microorganism synergistic mechanism (root secretion of organic acids + microbial activation of minerals) to significantly increase the organic matter content of engineering waste soil within 90 days, shortening the improvement cycle to 1 / 5 of traditional methods (which require 3-5 years). Increased sugarcane root vitality promotes the formation of waste soil aggregates and increases soil porosity.

Description

Technical Field

[0001] This invention relates to the field of soil improvement and ecological restoration technology, and in particular to a method for soilification of engineering waste based on the synergistic effect of water, fertilizer, organic matter, and sugarcane. Background Technology

[0002] The disposal of construction waste is a major technical and ecological challenge facing current project construction. Traditional disposal methods mainly involve open-air stockpiling, which not only requires specific equipment and incurs high maintenance costs, but also occupies a large amount of land resources. This construction waste is mainly composed of deep soil and rock, lacking organic matter, low in nutrient content, and with poor physical structure. This results in slow vegetation recovery at the stockpiles, low survival rates and limited growth of cash crops when planted directly, making it difficult to meet the requirements for land reclamation and ecological restoration.

[0003] Sugarcane (Saccharum spp.), as an important sugar and energy crop, is characterized by its large biomass, well-developed root system, and tolerance to poor soil conditions. During its growth, it significantly improves soil physical structure and introduces organic carbon through root exudates and litter, promoting soil aggregate formation. More importantly, the sugarcane rhizosphere is rich in various functional microorganisms, including Bacillus, Chryseolinea, Paenibacillus, Lysinibacillus, Truepera, Varibacter, Mesorhizobium, and Brevibacillus. These microorganisms not only activate nutrients (such as phosphorus and potassium) fixed in the waste soil but also secrete extracellular polysaccharides and organic acids, promoting mineral particle cementation and thus accelerating the "soilification" process of the waste soil.

[0004] In recent years, the "organic matter-plant-microorganism" synergistic improvement model has gradually become a research hotspot for degraded soil or non-arable land reconstruction. Studies have shown that the addition of exogenous organic matter (such as well-rotted livestock and poultry manure, biogas residue, green manure, etc.) can provide carbon and energy sources for microorganisms, stimulate the proliferation and metabolic activity of rhizosphere microbial communities, and thus improve nutrient cycling efficiency and soil structural stability. Applying this concept to the improvement of engineering waste soil, combined with the strong root penetration ability of sugarcane and its ability to construct rhizosphere micro-ecosystems, is expected to realize the functional transformation of waste soil from "inert matrix" to "active topsoil".

[0005] However, existing technologies mostly focus on the short-term regulation of the physicochemical properties of construction waste soil using single amendments (such as chemical fertilizers or ordinary organic fertilizers), neglecting the driving role of plant-microbe interactions in soil formation processes. In particular, they lack systematic soil transformation solutions specifically tailored to sugarcane, a high-biomass crop, and the unique characteristics of construction waste soil. Therefore, developing a soil transformation method for construction waste soil based on a four-dimensional synergistic mechanism of "water and fertilizer regulation—organic matter input—sugarcane planting—root microbial activation" is of significant practical importance and innovative value for realizing the resource utilization of construction waste soil, promoting the green and sustainable development of the sugarcane industry, and constructing a "city-agriculture" circular economy system. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for soilification of engineering waste based on the synergistic effect of water, fertilizer, organic matter, and sugarcane. The method provided by this invention can achieve soilification of engineering waste at low cost and high efficiency.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for soilification of engineering waste based on the synergistic effect of water, fertilizer, organic matter, and sugarcane, comprising the following steps:

[0009] Step 1: Cultivating sugarcane seedlings: Transplant the sugarcane tissue culture seedlings into a simulated substrate of slag soil for cultivation, and select qualified sugarcane seedlings.

[0010] Step 2, Transplanting sugarcane seedlings: Pre-treat the construction waste soil, and then transplant the sugarcane seedlings; the planting depth of the sugarcane seedlings is 5-7cm, and spray root-promoting fertilizer once on the day of planting;

[0011] 3–5 days before transplanting sugarcane seedlings, evenly spray the surface of the pre-treated slag soil with root-promoting fertilizer 2; before transplanting, apply 1×10 5 ~5×10 5 spores kg -1 Soil inoculation with arbuscular mycorrhizal fungi;

[0012] Step 3, Dynamic Gradient Water and Fertilizer Management: Tillering Stage: Spray water and fertilizer every 14 days during the tillering stage, at a rate of 1.0 L / m². 2 During the elongation period: Spray with a liquid fertilizer every 10 days, at a rate of 1.2 L / m². 2 Maturity stage: Spray with a liquid fertilizer every 21 days, at a rate of 0.8 L / m². 2 .

[0013] In a preferred embodiment of the present invention, in step 1, the method for preparing the slag-soil simulated matrix is ​​as follows: air-dried engineering slag, quartz sand, and sugarcane biochar are mixed evenly in a mass ratio of (7-8):(1-2):(0.5-1.0), and then the bulk density is adjusted to 1.60±0.05g cm³.-3 pH 6.8±0.2, organic matter ≤0.5% and saturated water content 22±2%.

[0014] In a preferred embodiment of the present invention, in step 1, sugarcane tissue culture seedlings are transplanted into a slag soil simulated substrate for cultivation. Specifically, qualified sugarcane seedlings are selected: those that have rooted for 30 days, have a plant height of 8-10 cm, and a root length ≥3 cm. After removing residual culture medium, they are transplanted into the slag soil simulated substrate at a depth of 2 cm. After 30 days of cultivation in the slag soil simulated substrate under conditions of 16 hours of light, 28±1℃, and 70±5% RH, qualified sugarcane seedlings with a plant height growth rate ≥50%, a root length growth rate ≥40%, a chlorophyll SPAD value ≥25, and root activity ≥100 μg TPF / g·h are selected.

[0015] In a preferred embodiment of the present invention, in step 2, the engineering waste soil is pretreated by: mechanically crushing the engineering waste soil to a particle size ≤ 5cm, while screening out gravel with a particle size > 5cm, and then adjusting the moisture content to 60% of the field water holding capacity.

[0016] In a preferred embodiment of the present invention, in step 2, the amount of rooting water-fertilizer 1 applied is 1.5–2.0 Lm. -2 The application rate of rooting fertilizer 2 is 0.8–1.2 Lm. -2 The rooting fertilizer 1 and rooting fertilizer 2 are the same.

[0017] The method for preparing the rooting fertilizer 1 is as follows: ferment livestock and poultry manure using compound microbial agent 4 to obtain fermentation product 4; add sodium naphthaleneacetate, potassium dihydrogen phosphate, humic acid, potassium indolebutyrate, and seaweed extract, accounting for 40.001–0.003 wt% of the fermentation product, to the fermentation product to obtain the rooting fertilizer 1.

[0018] By weight, the compound microbial agent 4 comprises 25-35 parts of Bacillus velezensis, 20-30 parts of Bacillus ammoniiphilus, 15-20 parts of Trichoderma reesei, 10-15 parts of Rhodopseudomonas palustris, and 3-5 parts of sugarcane bagasse biochar.

[0019] In a preferred embodiment of the present invention, the method for preparing the tillering stage water-fertilizer is as follows: livestock and poultry manure is fermented using compound microbial agent 1 to obtain fermentation product 1; zinc sulfate (10.05 wt%), ammonium molybdate (0.01 wt%), and sodium malate are added to the fermentation product 1 to obtain the tillering stage water-fertilizer; the concentration of sodium malate in the tillering stage water-fertilizer is 0.5 mmol / L.

[0020] By weight, the compound microbial agent 1 comprises 30-40 parts of Bacillus subtilis, 30-40 parts of Bacillus mucilaginosus, 15-20 parts of Trichoderma reesei, 10-15 parts of Rhodopseudomonas palustris, and 3-5 parts of sugarcane bagasse biochar.

[0021] In a preferred embodiment of the present invention, the method for preparing the elongation-period slurry is as follows: livestock and poultry manure is fermented using compound microbial agent 2 to obtain fermentation product 2; potassium humate (20.3 wt%), polyglutamic acid (0.1 wt%), potassium silicate, and fish protein (5 g / L) are added to the fermentation product 2 to obtain the elongation-period slurry; the concentration of potassium silicate in the elongation-period slurry is 2 mmol / L, and the concentration of fish protein is 5 g / L.

[0022] By weight, the compound microbial agent 2 comprises 25-35 parts of Bacillus subtilis, 25-35 parts of Bacillus mucilaginosus, 10-20 parts of Bacillus ammoniacum, 10-15 parts of Trichoderma reesei, 10-15 parts of Rhodopseudomonas palustris, and 3-5 parts of sugarcane bagasse biochar.

[0023] In a preferred embodiment of the present invention, the method for preparing the mature-stage water-fertilizer is as follows: fermenting livestock and poultry manure with compound microbial agent 3 to obtain fermentation product 3; adding 30.1 wt% chitosan oligosaccharide and 0.05 wt% choline chloride to the fermentation product 3 to obtain the mature-stage water-fertilizer;

[0024] By weight, the compound microbial agent 3 comprises 25-35 parts of Bacillus subtilis, 25-35 parts of Bacillus jellyoidis, 10-20 parts of Pseudomonas stutzeri, 10-15 parts of Trichoderma reesei, 5-10 parts of Rhodopseudomonas palustris, and 3-5 parts of bagasse biochar.

[0025] In a preferred embodiment of the present invention, when performing dynamic gradient water and fertilizer management, the normalized difference vegetation index (NDVI), normalized difference vegetation index (GNDVI), normalized difference red edge vegetation index (NDRE), and optimized soil regulation vegetation index (OSAVI) are collected daily from the engineering waste soil area using a multispectral scanning drone, with a resolution ≤5cm. The volumetric water content (θv) of the three soil layers is monitored at depths of 10cm, 30cm, and 50cm to measure the volumetric water content of the root layer in real time and calculate the effective water storage (REW) of the root layer.

[0026] The effective water storage capacity of the root layer REW = Σ(θv×ΔZ) - WP; where WP is the theoretical wilting coefficient, which is preset according to the type of slag soil (3% for sandy gravel slag soil; 12% for loamy slag soil; 20% for clay slag soil; WP = the above coefficient × total thickness of the root layer, the total thickness of the root layer of newly planted sugarcane is calculated on-site or estimated empirically, and the total thickness of the root layer of ratooned sugarcane is taken as 150cm); ΔZ is the depth.

[0027] The decision-making logic for determining the water and fertilizer management period is as follows:

[0028] a. When NDVI increases twice consecutively and NDVI≥0.6 and REW>45mm, the sugarcane is determined to have entered the elongation stage, and the elongation stage dynamic mode is activated;

[0029] b. When NDVI steadily decreases or GNDVI ≥ 0.65 and ΔGNDVI < 0.005 / d persists for 5 days, switch to mature-stage water and fertilizer;

[0030] c. If REW ≤ 30mm, immediately initiate irrigation compensation to make the water volume = 45mm - current REW;

[0031] d. Use the modified potassium deficiency index (MKDI) formula: MKDI = (NDRE × OSAVI) / GNDVI to determine whether the plant is under potassium deficiency stress, where:

[0032] 0.8≤MKDI≤11.0: Potassium is normal (K≥20g / kg);

[0033] 0.6 ≤ MKDI < 0.8: Mild potassium deficiency (K 15–20 g / kg);

[0034] MKDI < 0.6: Severe potassium deficiency (K < 15 g / kg);

[0035] When potassium is mildly deficient: increase the proportion of gelatinous Bacillus by 10%; if it is in the elongation stage, increase the amount of potassium silicate by 0.2 mmol / L.

[0036] When potassium is severely deficient: increase the proportion of gelatinous Bacillus by 20%, and if it is in the elongation stage, increase the amount of potassium silicate by 0.5 mmol / L.

[0037] The present invention discloses the following technical effects:

[0038] (1) Breakthrough improvement in soil improvement efficiency: Through the sugarcane-microorganism synergistic mechanism (root secretion of organic acids + microbial activation of minerals), the organic matter content of engineering waste soil is significantly increased within 90 days, and the improvement cycle is shortened to 1 / 5 of the traditional method (which takes 3-5 years). Sugarcane root vitality promotes the formation of waste soil aggregates and increases soil porosity.

[0039] (2) Growth-promoting compound microbial agents and enhanced growth and stress resistance: Existing technologies typically use single-species or general compound microbial agents, which suffer from limited functionality and weak targeting. Especially in harsh sugarcane environments, the survival rate of microorganisms is low, and the colonization effect is poor, making it difficult to effectively promote growth and improve the plant's condition. This invention, however, innovatively tailors four compound microbial agents (compound agents 1-4) for different stages of sugarcane growth (rooting, tillering, elongation, and maturity). The composition and proportion of these microorganisms are precisely designed to enhance root colonization, improve phosphorus and nitrogen fixation capacity, optimize ammonia nitrogen utilization, and enhance stress resistance. Simultaneously, the microbial agents utilize sugarcane bagasse biochar as a carrier, improving adaptability and survival rate in barren soil. Furthermore, the combination of seaweed extract, humic acid, and chitosan oligosaccharides further activates the plant's stress resistance mechanism and nutrient absorption efficiency. This design achieves synergistic effects from multiple factors, significantly improving the functional expression of the microbial agents in harsh environments and solving the core pain points of traditional technologies, such as weak targeting and unstable effects.

[0040] (3) Efficient utilization and precise dynamic regulation of water and fertilizer resources: Existing irrigation and fertilization technologies are mostly based on experience or fixed schedules, which cannot respond in real time to the actual state of crops and soil, and are prone to resource waste or stress. This technology constructs a phased gradient model of water and fertilizer management and monitors the above-ground and underground states in real time to achieve intelligent dynamic regulation of crop water and fertilizer requirements, minimize water and fertilizer waste, and improve fertilizer efficiency and yield.

[0041] (4) Significant economic, environmental and social benefits: Using livestock and poultry manure as the core raw material, a microbial-organic matter synergistic system is constructed, which significantly reduces the dependence on external chemical fertilizers and organic fertilizers, and the treatment cost is significantly lower than that of traditional methods; at the same time, it realizes the dual resource utilization of engineering waste and agricultural waste, turning waste into treasure, which is in line with the concept of circular economy and green development; its output value is not only reflected in the improved soil, but also creates significant economic value through the large-scale planting of sugarcane (which can be used in sugar production, energy and other fields), forming a virtuous cycle of ecological restoration and economic benefits; it has the potential for large-scale promotion with standardization and strong replicability, and provides an innovative solution for waste resource utilization and ecological restoration. Detailed Implementation

[0042] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0043] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0044] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0045] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0046] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0047] In this invention, sugarcane biochar is prepared using methods well known to those skilled in the art, such as hydrothermal carbonization. Sugarcane bagasse and water are mixed at a mass-to-volume ratio of 1:(6-8), placed in a high-pressure reactor, and reacted at 210-230°C for 2-4 hours. After the reaction, the mixture is separated into solid and liquid components, washed with clean water, dried at 105°C to constant weight, and ground through a 100-mesh sieve. The hydrothermal biochar has a pH of 5.5-7.0, an oxygen-to-carbon ratio (O / C) of 0.4-0.6, and a hydrogen-to-carbon ratio (H / C) of 0.8-1.0.

[0048] The seaweed extract was prepared by alkaline extraction. Seaweed powder was added to 1-2% KOH solution at a ratio of 1:15-20 (w / v), stirred at 60-80℃ for 2-4 hours, cooled, and the pH was adjusted to 6-8. After centrifugation, a clear supernatant was obtained. The supernatant was concentrated to solids in a vacuum concentrator (vacuum -0.08MPa, ≤60℃) and then spray-dried to obtain the seaweed polysaccharide extract.

[0049] In this invention, the microorganisms involved (Bacillus belye, Bacillus ammonia-loving, Trichoderma reesei, Rhodopseudomonas palustris, Bacillus subtilis, Bacillus mucilaginosus, Trichoderma reesei, and Pseudomonas steganus) were all purchased from the China Agricultural Microbial Culture Collection Center.

[0050] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0051] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0052] Example 1

[0053] The Pinglu Canal Horse Road Hub, Section 11, No. 5 earthwork storage site of the Pinglu Canal waterway. The planting area is 380 mu (approximately 25 hectares) of Guitang No. 44 sugarcane. The height of the construction waste pile should not be less than 50 cm. The land is red and yellow soil dry farmland. (Planted in March, soil fertility tested in July to reach level 6).

[0054] Specifically as follows:

[0055] Step 1: Mix air-dried construction waste (200 mesh), quartz sand, and sugarcane bagasse biochar at a mass ratio of 8:2:1.0, and adjust the bulk density to 1.60±0.05g / cm³. -3 A homogenized slag-soil simulated substrate was obtained with pH 6.8±0.2, organic matter ≤0.5%, and saturated water content 22±2%. Sugarcane tissue culture seedlings with roots for 30 days, plant height 8-10cm, and root length ≥3cm were selected. After removing residual culture medium, they were transplanted into transparent plastic root tubes with an inner diameter of 4cm and a height of 60cm. The root tubes were filled with slag-soil simulated substrate at a transplanting depth of 2cm. After culturing in the simulated substrate for 30 days under the conditions of 16h light, 28±1℃, and RH 70±5%, tissue culture seedlings with a plant height growth rate ≥50%, root length growth rate ≥40%, chlorophyll SPAD value ≥25, and root activity ≥100μg TPF / g·h were qualified varieties.

[0056] Step 2: Mechanically crush the construction waste to a particle size ≤ 5cm, while sieving out gravel with a particle size > 5cm. Adjust the moisture content to 60% of field capacity by spraying. Three days before planting the sugarcane tissue culture seedlings, evenly spray the surface of the waste with root-promoting liquid fertilizer at a rate of 1.5–2.0 L / m³. -2 Transplant the stress-resistant sugarcane seedlings into the slag soil at a depth of 5–7 cm. On the day of planting, spray with root-promoting liquid fertilizer at a rate of 0.8–1.2 Lm. -2 Before transplanting, tissue culture seedlings should be treated with 1×10 5 ~5×10 5 spores kg -1 Soil inoculation with arbuscular mycorrhizal fungi (Glomus etunicatum).

[0057] The preparation method of the rooting fertilizer is as follows: The compound microbial agent 4 is mixed with livestock and poultry manure (the amount of compound microbial agent is 4 wt% of the livestock and poultry manure), and fermented (air is injected into the liquid manure through an aeration disc to promote the large-scale reproduction and metabolism of aerobic microorganisms, maintaining the fermentation temperature at 30℃-35℃, and fermenting for 72-75 hours) to obtain fermentation product 4; 40.003 wt% sodium naphthaleneacetate, 0.1 wt% potassium dihydrogen phosphate, 2 wt% humic acid, 0.001 wt% potassium indolebutyrate, and 0.5 wt% seaweed extract are added to the fermentation product to obtain the rooting fertilizer 1.

[0058] By weight, the compound microbial agent 4 comprises 35 parts of Bacillus belye, 30 parts of Bacillus ammoniacum, 15 parts of Trichoderma reesei, 15 parts of Rhodopseudomonas palustris, and 5 parts of sugarcane bagasse biochar.

[0059] Step 3: Finally, based on the drone's spectral data and online soil moisture data, dynamic gradient water and fertilizer management is implemented throughout the sugarcane growth cycle to promote sugarcane growth and further secretion of organic acids by the sugarcane roots to improve the soil. Tillering stage: Spray water and fertilizer every 14 days, at a rate of 1.0 L / m². 2 During the elongation period: Spray with a liquid fertilizer every 10 days, at a rate of 1.2 L / m². 2 Maturity stage: Spray with water-soluble fertilizer every 21 days, at a rate of 0.8 L / m³. 2 .

[0060] The preparation method of the tillering stage water-fertilizer is as follows: Compound microbial agent 1 is mixed with livestock and poultry manure (the amount of compound microbial agent 1 is 4 wt% of the livestock and poultry manure), and fermented (air is injected into the liquid manure through an aeration disc to promote the large-scale reproduction and metabolism of aerobic microorganisms. The fermentation temperature is maintained at 35℃-38℃ for 72-75 hours) to obtain fermentation product 1; zinc sulfate (10.05 wt%), ammonium molybdate (0.01 wt%), and sodium malate are added to the fermentation product 1 to obtain the tillering stage water-fertilizer; the concentration of sodium malate in the tillering stage water-fertilizer is 0.5 mmol / L.

[0061] By weight, the compound microbial agent 1 comprises 35 parts of Bacillus subtilis, 35 parts of Bacillus mucilaginosus, 15 parts of Trichoderma reesei, 10 parts of Rhodopseudomonas palustris, and 5 parts of sugarcane bagasse biochar.

[0062] The preparation method of the elongation-period slurry is as follows: Compound microbial agent 2 is mixed with livestock and poultry manure (the amount of compound microbial agent 2 is 4 wt% of the livestock and poultry manure), and fermented (air is injected into the liquid manure through an aeration disc to promote the proliferation and metabolism of aerobic microorganisms. The fermentation temperature is maintained at 35℃-38℃ for 72-75 hours) to obtain fermentation product 2; potassium humate (20.3 wt%), polyglutamic acid (0.1 wt%), potassium silicate, and fish protein are added to the fermentation product 2 to obtain the elongation-period slurry; the concentration of potassium silicate in the elongation-period slurry is 2 mmol / L, and the concentration of fish protein is 5 g / L.

[0063] By weight, the compound microbial agent 2 comprises 30 parts of Bacillus subtilis, 35 parts of Bacillus mucilaginosus, 10 parts of Bacillus ammoniacum, 10 parts of Trichoderma reesei, 12 parts of Rhodopseudomonas palustris, and 3 parts of sugarcane bagasse biochar.

[0064] The method for preparing the mature-stage water-fertilizer is as follows: Compound microbial agent 3 is mixed with livestock and poultry manure (the amount of compound microbial agent 3 is 4 wt% of the livestock and poultry manure), and fermented (air is injected into the liquid manure through an aeration disc to promote the proliferation and metabolism of aerobic microorganisms. The fermentation temperature is maintained at 35℃-38℃ for 72-75 hours) to obtain fermentation product 3; 30.1 wt% of chitosan oligosaccharide and 0.05 wt% of choline chloride are added to the fermentation product 3 to obtain the mature-stage water-fertilizer.

[0065] By weight, the compound microbial agent 3 comprises 25 parts of Bacillus subtilis, 30 parts of Bacillus mucilaginosus, 20 parts of Pseudomonas stutzeri, 12 parts of Trichoderma reesei, 10 parts of Rhodopseudomonas palustris, and 3 parts of bagasse biochar.

[0066] When implementing dynamic gradient water and fertilizer management, the normalized difference vegetation index (NDVI), normalized difference vegetation index (GNDVI), normalized difference red edge vegetation index (NDRE), and optimized soil regulation vegetation index (OSAVI) are collected daily from the engineering waste soil area using multispectral scanning drones, with a resolution ≤5cm. The three-layer soil volumetric water content (θv) is monitored at depths of 10cm, 30cm, and 50cm to measure the root zone soil volumetric water content in real time and calculate the effective water storage capacity (REW) of the root zone.

[0067] Effective water storage in the root zone REW = Σ(θv×ΔZ) - WP; where WP is the theoretical wilting coefficient, preset according to the type of slag; ΔZ is the depth;

[0068] The decision-making logic for determining the water and fertilizer management period is as follows:

[0069] a. When NDVI increases twice consecutively and NDVI≥0.6 and REW>45mm, the sugarcane is determined to have entered the elongation stage, and the elongation stage dynamic mode is activated;

[0070] b. When NDVI steadily decreases or GNDVI ≥ 0.65 and ΔGNDVI < 0.005 / d persists for 5 days, switch to mature-stage water and fertilizer;

[0071] c. If REW ≤ 30mm, immediately initiate irrigation compensation to make the water volume = 45mm - current REW;

[0072] d. Use the modified potassium deficiency index (MKDI) formula: MKDI = (NDRE × OSAVI) / GNDVI to determine whether the plant is under potassium deficiency stress, where:

[0073] 0.8≤MKDI≤11.0: Potassium is normal (K≥20g / kg);

[0074] 0.6 ≤ MKDI < 0.8: Mild potassium deficiency (K 15–20 g / kg);

[0075] MKDI < 0.6: Severe potassium deficiency (K < 15 g / kg);

[0076] When potassium is mildly deficient: increase the proportion of gelatinous Bacillus by 10%; if it is in the elongation stage, increase the amount of potassium silicate by 0.2 mmol / L.

[0077] When potassium is severely deficient: increase the proportion of gelatinous Bacillus by 20%, and if it is in the elongation stage, increase the amount of potassium silicate by 0.5 mmol / L.

[0078] The parameters of the engineering waste soil before and after treatment are shown in Table 1:

[0079] Table 1

[0080]

[0081]

[0082] 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. A method for soilification of engineering waste based on water, fertilizer, organic matter, and sugarcane synergy, characterized in that, Includes the following steps: Step 1: Cultivating sugarcane seedlings: Transplant the sugarcane tissue culture seedlings into a simulated substrate of slag soil for cultivation, and select qualified sugarcane seedlings. Step 2, Transplanting sugarcane seedlings: Pre-treat the construction waste soil, and then transplant the sugarcane seedlings; the planting depth of the sugarcane seedlings is 5-7 cm, and spray root-promoting water fertilizer once on the day of planting; 3–5 days before transplanting sugarcane seedlings, evenly spray the surface of the pre-treated slag soil with root-promoting fertilizer 2; before transplanting, apply 1×10 5 ~5×10 5 spores kg -1 Soil inoculation with arbuscular mycorrhizal fungi; Step 3, Dynamic Gradient Water and Fertilizer Management: Tillering Stage: Spray water and fertilizer every 14 days during the tillering stage, at a rate of 1.0 L / m². 2 During the elongation period: Spray with a liquid fertilizer every 10 days, at a rate of 1.2 L / m². 2 Maturity stage: Spray with water-based fertilizer every 21 days, at a rate of 0.8 L / m³. 2 ; The method for preparing the tillering stage water-fertilizer is as follows: Livestock and poultry manure is fermented using compound microbial agent 1 to obtain fermentation product 1; zinc sulfate (0.05 wt%), ammonium molybdate (0.01 wt%), and sodium malate are added to the fermentation product 1 to obtain the tillering stage water-fertilizer; the concentration of sodium malate in the tillering stage water-fertilizer is 0.5 mmol / L. By weight, the compound microbial agent 1 comprises 30-40 parts of Bacillus subtilis, 30-40 parts of Bacillus mucilaginosus, 15-20 parts of Trichoderma reesei, 10-15 parts of Rhodopseudomonas palustris, and 3-5 parts of sugarcane bagasse biochar. The method for preparing the elongation-period slurry is as follows: Livestock and poultry manure is fermented using compound microbial agent 2 to obtain fermentation product 2; potassium humate (0.3 wt%), polyglutamic acid (0.1 wt%), potassium silicate, and fish protein (accounting for 0.3 wt%) are added to the fermentation product 2 to obtain the elongation-period slurry; the concentration of potassium silicate in the elongation-period slurry is 2 mmol / L, and the concentration of fish protein is 5 g / L. By weight, the compound microbial agent 2 includes 25-35 parts of Bacillus subtilis, 25-35 parts of Bacillus jellyii, 10-20 parts of Bacillus ammoniacum, 10-15 parts of Trichoderma reesei, 10-15 parts of Rhodopseudomonas palustris, and 3-5 parts of sugarcane bagasse biochar. The method for preparing the mature stage water-fertilizer is as follows: fermenting livestock and poultry manure with compound microbial agent 3 to obtain fermentation product 3; adding 0.1 wt% chitosan oligosaccharide and 0.05 wt% choline chloride to the fermentation product 3 to obtain the mature stage water-fertilizer; By weight, the compound microbial agent 3 includes 25-35 parts of Bacillus subtilis, 25-35 parts of Bacillus mucilaginosus, 10-20 parts of Pseudomonas skeletoni, 10-15 parts of Trichoderma reesei, 5-10 parts of Rhodopseudomonas palustris, and 3-5 parts of bagasse biochar. When implementing dynamic gradient water and fertilizer management, the normalized difference vegetation index (NDVI), normalized difference vegetation index (GNDVI), normalized difference red edge vegetation index (NDRE), and optimized soil regulation vegetation index (OSAVI) are collected daily from the engineering waste soil area using multispectral scanning drones, with a resolution ≤5 cm. The volumetric water content (θv) of the three soil layers is monitored at depths of 10 cm, 30 cm, and 50 cm to measure the volumetric water content of the root zone in real time and calculate the effective water storage (REW) of the root zone. Effective water storage in the root zone REW = Σ(θv×ΔZ) - WP; where WP is the theoretical wilting coefficient, preset according to the type of slag; ΔZ is the depth; The decision-making logic for determining the water and fertilizer management period is as follows: a. When NDVI increases twice consecutively and NDVI ≥ 0.6 and REW > 45mm, the sugarcane is determined to have entered the elongation stage, and the elongation stage dynamic mode is activated; b. When NDVI steadily decreases or GNDVI ≥ 0.65 and ΔGNDVI < 0.005 / d persists for 5 days, switch to mature-stage water and fertilizer; c. If REW ≤ 30 mm, immediately initiate irrigation compensation to make the water volume = 45 mm - current REW; d. Use the modified potassium deficiency index (MKDI) formula: MKDI = (NDRE × OSAVI) / GNDVI to determine whether the plant is under potassium deficiency stress, where: 0.8≤MKDI≤1.0: Potassium is normal; 0.6 ≤ MKDI < 0.8: Mild potassium deficiency; MKDI < 0.6: Severe potassium deficiency; When potassium is mildly deficient: increase the proportion of gelatinous Bacillus by 10%; if it is in the elongation phase, increase the amount of potassium silicate by 0.2 mmol / L. When potassium is severely deficient: the proportion of gelatinous Bacillus increases by 20%, and if it is in the elongation phase, the amount of potassium silicate added increases by 0.5 mmol / L.

2. The method for soilification of engineering waste based on water, fertilizer, organic matter, and sugarcane synergy according to claim 1, characterized in that, In step 1, the preparation method of the simulated slag matrix is ​​as follows: air-dried engineering slag, quartz sand, and sugarcane biochar are mixed evenly in a mass ratio of (7-8):(1-2):(0.5-1.0), and then the bulk density is adjusted to 1.60±0.05 g cm³. -3 pH 6.8±0.2, organic matter ≤0.5% and saturated water content 22±2%.

3. The method for soilification of engineering waste based on water, fertilizer, organic matter, and sugarcane synergy according to claim 1, characterized in that, In step 1, sugarcane tissue culture seedlings are transplanted into a slag soil simulated substrate for cultivation. Qualified sugarcane seedlings are selected, specifically: sugarcane tissue culture seedlings that have rooted for 30 days, have a plant height of 8–10 cm, and a root length ≥3 cm are selected. After removing residual culture medium, they are transplanted into the slag soil simulated substrate at a transplanting depth of 2 cm. After 30 days of cultivation in the slag soil simulated substrate under conditions of 16 h of light, 28 ± 1 ℃, and RH 70 ± 5%, qualified sugarcane seedlings with a plant height growth rate ≥50%, a root length growth rate ≥40%, a chlorophyll SPAD value ≥25, and root activity ≥100 μg TPF / g·h are selected.

4. The method for soilification of engineering waste based on water, fertilizer, organic matter, and sugarcane synergy according to claim 1, characterized in that, In step 2, the construction waste soil is pretreated by mechanically crushing it to a particle size of ≤5 cm, while screening out gravel with a particle size >5 cm, and then adjusting the moisture content to 60% of the field water holding capacity.

5. The method for soilification of engineering waste based on water, fertilizer, organic matter, and sugarcane synergy according to claim 1, characterized in that, In step 2, the application rate of rooting water and fertilizer 1 is 1.5–2.0 L / m³. -2 The application rate of rooting fertilizer 2 is 0.8–1.2 Lm. -2 The rooting fertilizer 1 and rooting fertilizer 2 are the same. The method for preparing the rooting fertilizer 1 is as follows: fermenting livestock and poultry manure with compound microbial agent 4 to obtain fermentation product 4; adding sodium naphthaleneacetate, potassium dihydrogen phosphate, humic acid, potassium indolebutyrate, and seaweed extract at a ratio of 0.001–0.003 wt% to the fermentation product 4 to obtain the rooting fertilizer 1. By weight, the compound microbial agent 4 comprises 25-35 parts of Bacillus belye, 20-30 parts of Bacillus ammoniacum, 15-20 parts of Trichoderma reesei, 10-15 parts of Rhodopseudomonas palustris, and 3-5 parts of sugarcane bagasse biochar.

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