A composite functional material for synchronous fertilization and treatment of soda saline soil

Abstract

The application discloses a kind of for soda saline-alkali soil synchronous fertilization and management of compound functional material.The compound functional material provided by the application includes the following component composition: humus organic fertilizer 2-4 parts by weight, natural nanometer mineral powder 0.25-0.5 parts by weight, plant amino acid peptide 0.25-0.5 parts by weight, hydrothermal biochar 1 part by weight.The application breaks through the limitation of traditional technology by the synergistic design of organic-inorganic-biological material, realizes carbon fixation and fertilization synergistic effect.The core of the application is: fast alkali reduction and salt control, efficient supplement of organic matter and available nutrients, long-acting fertilization function, and can promote the formation of soil stable aggregate structure, enhance the water and fertilizer retention capacity of soil, simultaneously eliminate saline-alkali barrier and improve soil fertility, provide an integrated solution for soda saline-alkali land management.In addition, the compound functional material formula has wide application range, can be used for the management of soda saline-alkali soil in different regions, and can quickly eliminate saline-alkali barrier factor in dry farming and paddy field planting modes.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, specifically relating to a composite functional material for simultaneous fertilization and remediation of soda saline-alkali soil. Background Technology

[0002] Soda saline-alkali soil is a highly alkaline soil with sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) as its main salts. Due to its high pH value, high alkalinity, and high sodium ion content, the soil has poor structure, poor permeability, and low organic matter and available nutrient content, which seriously restricts crop growth and ecosystem function.

[0003] The current methods for improving soda saline-alkali land mainly include: (1) physical measures, such as irrigation and drainage projects, land leveling, soil replacement, deep loosening and deep plowing, etc., which can reduce salt concentration in the short term, but the project is large and costly, and it is easy to cause secondary salt migration, making it difficult to promote on a large scale; (2) chemical measures, such as applying desulfurized gypsum, phosphogypsum, aluminum sulfate, fly ash, wood vinegar, etc. to improve the physical and chemical properties of the soil, which can reduce pH value in the short term, but long-term use can easily lead to soil compaction or secondary pollution; (3) biological measures, such as planting halophytes or salt-tolerant green manure, increasing the application of organic fertilizer or salt-tolerant microbial agents, etc., which are slow to take effect, and traditional organic fertilizers have low decomposition efficiency and weak carbon fixation capacity in a strongly alkaline environment.

[0004] CN113621377A discloses a soil conditioner, which has significant conditioning effects, but has the following problems: the components contain a large amount of inorganic fertilizers (N, P, K), which can quickly provide nutrients to crops to increase yield, but may rebound once use is stopped, and increase the concentration of soil salt ions, leading to continuous salt accumulation; it relies on the chemical material calcium sulfate to replace sodium ions, so the effect of reducing alkali and controlling salt is slow, and it belongs to chemical improvement technology, which has the risk of causing secondary pollution to the soil; it is only suitable for medium and low saline-alkali soils with a pH value of 8.7; high dosage and step-by-step application make the operation complicated and costly.

[0005] The core technologies of CN116606657A and CN109705872A rely on the calcium salt ion replacement effect of chemical materials calcium chloride and desulfurized gypsum. They also require a large amount of irrigation water to leach sodium ions in order to reduce alkali and control salt. This is a chemical improvement technology, which has the risk of causing secondary pollution to the soil and requires a large amount of water resources. It is only suitable for paddy fields or areas with guaranteed irrigation, and its effect is limited in arid areas or dry land.

[0006] The core technology of CN118272092A is to improve high-salt, heavily alkaline, and infertile soils through physical adsorption, chemical passivation, and topsoil. However, this technology not only poses a risk of secondary pollution to the soil but also increases costs and consumes resources due to the topsoil. This design still belongs to the traditional method of improving saline-alkali land, and the literature does not provide data on the application effect.

[0007] The core technology of CN114836220A is based on chemical materials, supplemented by organic active substances and plant growth hormones. It focuses on application during the rice transplanting and greening-up stage to strongly stimulate explosive root growth, promoting rapid greening and adaptation to adverse conditions. This patented technology is highly targeted and fast-acting in solving the problems of seedling death and stunted growth during the greening-up stage, serving as an emergency measure. However, its effects on improving soil organic matter, long-term soil structure (aggregates), and microbial activity are relatively weak. Furthermore, its long-term reliance on exogenous chemical substances and potent hormones may pose a potential risk to the balance of the soil ecosystem. Its high specificity for the rice greening-up stage limits its impact on other crops or long-term soil improvement goals (such as fertilization), resulting in a narrow application scope.

[0008] CN104610974A proposes using the activation products of attapulgite and humic acid materials under the action of concentrated sulfuric acid to directly neutralize soil alkalinity and exchange sodium ions, achieving rapid reduction of alkalinity. This is a traditional chemical improvement approach, but its strong acid process poses operational safety hazards and may leave residual sulfate ions (SO4). 2- Long-term use of this product can lead to environmental risks such as soil compaction and secondary salinization. Its strong acid treatment destroys the active structure of soil humic acid, resulting in insufficient long-term organic carbon supply and limited organic matter replenishment.

[0009] It is evident that most existing improvement methods focus on a single objective, such as reducing salinity or adjusting acidity and alkali, which is costly and carries the potential risk of secondary pollution. They lack multi-objective synergistic technologies for reducing alkali and controlling salinity, structural repair, organic matter enhancement and fertilization in soda saline-alkali soil, making it difficult to achieve the organic combination of fundamental governance of soda saline-alkali land and continuous improvement of soil quality.

[0010] In view of this, the present invention is hereby proposed. Summary of the Invention

[0011] The purpose of this invention is to provide a composite functional material for the simultaneous fertilization and remediation of soda saline-alkali soil. This composite functional material overcomes the problems of low decomposition efficiency and weak carbon fixation capacity of traditional organic fertilizers in strongly alkaline environments. It simultaneously achieves multiple goals, including rapid alkali reduction and salt control, efficient replenishment of organic matter, long-term fertilization, construction of stable aggregate structure, and enhancement of soil water and fertilizer retention capacity, providing an integrated solution for the remediation of soda saline-alkali soil.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a composite functional material comprising the following components: 2-4 parts by weight of humus organic fertilizer, 0.25-0.5 parts by weight of natural nano-mineral powder, 0.25-0.5 parts by weight of plant amino acid peptides, and 1 part by weight of hydrothermal biochar.

[0013] This invention selects four components: humus organic fertilizer, natural nano-mineral powder, plant amino acid peptides, and hydrothermal biochar. By optimizing the compounding ratio, it fully leverages their synergistic effect to effectively treat the properties of soda-saline-alkali soils, as detailed below: 1) Natural nano-mineral powder: With its small particle size and high surface activity, it significantly enhances ion adsorption capacity, efficiently adsorbing and reducing soil sodium. + Concentration, rapidly reducing soil alkalinity.

[0014] 2) Hydrothermal biochar: As a core porous carrier, it not only effectively adsorbs water and nutrients, improves the soil's water and fertilizer retention capacity, and reduces leaching losses, but also loads nano-minerals and plant amino acid peptides, prolonging their slow-release effect, achieving long-term alkali reduction and preventing salt and alkali rebound; at the same time, hydrothermal biochar itself also has a long-term carbon fixation effect.

[0015] 3) Humus organic fertilizer: provides slow release of nutrients, ensuring a long-term stable supply of soil nutrients.

[0016] 4) Plant amino acid peptides: rich in organic matter, nitrogen, phosphorus and potassium and other essential nutrients for plants, which can be quickly supplied to plants; the small molecule active substances contained therein can further stimulate crop resistance and improve the survival rate under salt stress.

[0017] The synergistic effect mechanism of the above four components is as follows: 1) Hydrothermal biochar and humic acid in humic soil organic fertilizer effectively promote the formation of stable soil aggregates through oxidative coupling. 2) Plant amino acid peptides recruit beneficial microorganisms (such as Bacillus subtilis and other growth-promoting bacteria) to synergistically construct an "artificial microbial factory" with the microporous structure of hydrothermal biochar, thereby improving the soil micro-ecological environment. 3) All the above components interact to form an "organic-inorganic-biological" composite system. In summary, the technical advantage of this invention is that through systematic biological synergistic design, it provides an integrated solution of "rapid improvement - long-term fertilization - carbon sequestration and emission reduction" for the treatment and improvement of soda saline-alkali land, representing the "green value-added" direction of saline-alkali land treatment.

[0018] Furthermore, the humus organic fertilizer has the following characteristics: organic matter content 12-14 wt%, total nitrogen content 1.0-1.16 wt%, phosphorus content (calculated as P2O5) 3.0-3.15 wt%, and potassium content (calculated as K2O) 1.7-1.87 wt%.

[0019] The natural nano-mineral powder has the following characteristics: calcium 0.54-0.56 wt%, magnesium 0.21-0.23 wt%, copper 0.00015-0.0002 wt%, iron 1.59-1.69 wt%, manganese 0.026-0.028 wt%, zinc 0.0055-0.006 wt%, and selenium 0.035-0.04 mg / kg.

[0020] The plant amino acid peptides have the following characteristics: total nitrogen content 8.5-8.92 wt%, phosphorus content (based on P2O5) 5.0-5.14 wt%, potassium content (based on K2O) 6.0-6.5 wt%, organic matter content 75-83.8 wt%, free amino acid content 14-14.9 wt%, calcium content 1.0-1.1 wt%, magnesium content 0.55-0.64 wt%, sulfur content 1.28-1.38 wt%, copper content 0.02%, iron content 0.02 wt%, and manganese content 0.02 wt%.

[0021] The hydrothermal biochar has the following characteristics: specific surface area 620-802 m² 2 / g, total nitrogen content 0.9-0.994wt%, phosphorus content (based on P2O5) 1.5-1.58wt%, potassium content (based on K2O) 4.5-4.62wt%, calcium content 0.31-0.36wt%, magnesium content 0.30-0.35wt%, pH 4.5-5.06.

[0022] As a specific embodiment of the present invention, the composite functional material is composed of the following components: 4 parts by weight of humus organic fertilizer, 0.25 parts by weight of natural nano-mineral powder, 0.25 parts by weight of plant amino acid peptides, and 1 part by weight of hydrothermal biochar.

[0023] Secondly, the present invention provides a method for treating soda-saline-alkali soil by applying the above-mentioned composite functional material to the soil.

[0024] The application rate of the composite functional material is more than 2% of the soil mass, preferably 2-3%.

[0025] The soda-saline-alkali soil has the following characteristics: organic matter content of basic soil nutrients is 5.82-9.20 g / kg, available nitrogen is 18.0-21.8 mg / kg, available phosphorus is 12.6-23.5 mg / kg, available potassium is 181-179 mg / kg, soil micro-aggregate composition is 61.90-88.17%, total salt content is 3.6 g / kg, alkalinity is 53.1-102%, and pH value is 10.28-10.4.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are: Addressing the three core challenges in the remediation of soda-saline-alkali land—difficulty in reducing alkali and controlling salinity, slow improvement of organic matter, and insufficient synergy between carbon sequestration and fertilization—this invention overcomes the limitations of traditional technologies through the synergistic design of organic-inorganic-biomaterials. It provides a specialized composite functional material formula for the remediation and fertilization of soda-saline-alkali soils, enhancing the synergistic effect of organic matter and fertilization. This formula combines rapid alkali reduction and salinity control, efficient replenishment of organic matter and readily available nutrients, and long-lasting fertilization. It also promotes the formation of stable aggregate structures and enhances the soil's water and fertilizer retention capacity, achieving simultaneous elimination of salinity barriers and improvement of soil fertility, providing an integrated solution for the remediation of soda-saline-alkali land. Furthermore, this formula has a wide range of applications, capable of rapidly eliminating salinity barriers in various regions of soda-saline-alkali soil, as well as in dryland and paddy fields. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0028] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0029] Unless otherwise specified, all reagents, materials, instruments, etc. used in the following examples are commercially available.

[0030] The raw materials used in the following examples: Humus organic fertilizer: This is an environmentally friendly organic fertilizer rich in humic acid, made primarily from crop straw, with the addition of photosynthetic carbon-fixing and anaerobic compound microbial agents, through long-term natural fermentation and decomposition. The material is loose and porous, rich in organic matter, beneficial bacteria, humic acid, and medium-quantity elements such as calcium and magnesium. Its nitrogen, phosphorus, and potassium content is significantly higher than that of organic fertilizers produced by ordinary fermentation processes. It has strong water permeability and aeration, significantly reducing soil bulk density and enhancing water retention. Through ion exchange, it replaces sodium ions, thereby regulating soil salinity. Its organic matter content is 14%, total nitrogen content is 1.16%, phosphorus (as P2O5) content is 3.15%, and potassium (as K2O) content is 1.87%. It was purchased from Shanxi Weiai Quantum Ecological Technology Co., Ltd.

[0031] Natural nano-mineral powder: This material is made from pure natural minerals. It contains 0.56% calcium, 0.23% magnesium, 0.0002% copper, 1.69% iron, 0.028% manganese, 0.006% zinc, and 0.04 mg / kg selenium. This material is porous and has ion exchange capacity, which enhances soil aeration and water retention. It also regulates soil salinization by releasing beneficial ions such as calcium and magnesium to replace sodium ions. Purchased from Runming Bioengineering (Dalian) Co., Ltd., particle size 100 mesh.

[0032] Plant amino acid peptides: This is a pollution-free, biological organic plant nutrient solution made primarily from corn seed coat and germ, supplemented with soybean meal, through low-temperature fermentation. It is rich in organic matter, plant peptides, and free amino acids. The total nitrogen content is 8.92%, phosphorus (as P2O5) is 5.14%, potassium (as K2O) is 6.5%, organic matter content is 83.8%, free amino acid content is 14.9%, calcium content is 1.1%, magnesium content is 0.64%, sulfur content is 1.28-1.38%, copper content is 0.02%, iron content is 0.02%, and manganese content is 0.02%. Purchased from Beijing Futelai Compound Fertilizer Co., Ltd.

[0033] Hydrothermal biochar: An eco-friendly and pollution-free material characterized by its porosity and high specific surface area (802 m² / g), total nitrogen content of 0.994%, phosphorus (as P₂O₅) content of 1.58%, potassium (as K₂O) content of 4.62%, pH of 5.06, calcium content of 0.36%, and magnesium content of 0.35%. It can adsorb moisture and nutrients from the soil, thus significantly improving the soil's water and fertilizer retention capacity. This product, prepared by Neixiang County Senmiao Energy Saving Technology Co., Ltd., uses corn stalks as raw material and is stored in a hydrothermal reactor at a constant temperature of 200℃. The preparation steps are as follows: Clean the inner pot of the 20L hydrothermal reactor; weigh 2KG of corn stalk granules and set aside; first, add one-third of the weighed water to the hydrothermal reactor, then pour the weighed corn stalks into the reactor, and add the remaining water, stirring evenly; drop the stirring paddle into the hydrothermal reactor, align the screw holes, and secure it with screws; connect the cooling circulating water for the stirring paddle; install the stirring paddle belt. Okay, insert the temperature probe into the temperature measuring tube inside the reactor; set the heating temperature controller and the reactor temperature controller; turn on the stirring paddle control power; turn on the reactor heating power, heat to the target temperature of 200 degrees Celsius, start timing the heating, stop the hydrothermal reactor heating after 1 hour, and let it cool naturally to room temperature; open the reactor lid and scoop the hydrothermal material into the filter bag to filter the hydrothermal liquid; put the filtered material and filter bag into the dewatering machine for dehydration; take out the dehydrated material and filter bag, put the corn stalk hydrothermal charcoal into the tray and dry it naturally (in the sun); bag the dried corn stalk biocharcoal, label it, and weigh it.

[0034] All of the above materials are natural, pollution-free, eco-friendly and environmentally friendly.

[0035] Example 1: Formulation and Material Screening of Composite Functional Material for Soda-Based Saline-Alkali Soil Fertilization 1.1 Test soil: The soil was collected from paddy fields in Da'an County, Baicheng City, Jilin Province. The soil pH was 9.54, alkalinity was 24.3%, and bicarbonate ion content was 1.22 g / kg. It is a typical severely soda saline-alkali soil. The basic soil nutrients included organic matter content of 12.7 g / kg, available nitrogen of 88.2 mg / kg, available phosphorus of 17.9 mg / kg, and available potassium of 156 mg / kg.

[0036] 1.2 Test materials: The test materials were humus organic fertilizer, nano mineral powder, plant protein peptides, biochar, desulfurized gypsum, and commercial organic fertilizer.

[0037] For detailed information on humus organic fertilizer, nano-mineral powder, plant peptides, and biochar, please refer to the invention description.

[0038] Desulfurized gypsum powder: The main chemical component is calcium sulfate dihydrate (CaSO4·2H2O), with a content of ≥90%. It is purchased from Beijing Huanmei Century Gardening Supplies Co., Ltd., with a particle size of 40-60 micrometers and a packaging size of 20kg / bag.

[0039] Commercial organic fertilizer: Organic matter content is 16%, total nitrogen content is 1.6%, phosphorus (as P2O5) content is 1.5%, potassium (as K2O) content is 1.1%, calcium content is 2.5%, and magnesium content is 0.25%. Purchased from Beijing Huanmei Century Gardening Supplies Co., Ltd., model 20kg / bag.

[0040] 1.3 The treatment number and dosage are shown in Table 1.

[0041]

[0042] 1.4 Test Implementation and Operation Weigh out several portions of 3 kg of soda-alkali soil, adding 1% and 2% of the soil mass respectively. Add the six materials mentioned above to the soil separately and mix thoroughly. Label these samples D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, and D12. Then, place the mixed soil samples into plastic culture containers and label them accordingly D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, and D12. A control group (DCK) was set up without any added materials.

[0043] 1.5 Sowing and Daily Management Evenly water each pot with 500 ml of deionized water. After the water has completely seeped in, mix the seeds of bitter bean, corn, and crested wheatgrass in the correct proportions and sow them. Cover the seeds with a 2 cm layer of original soda-alkali soil. Place the pots in a suitable environment and mist regularly to keep the soil surface moist until germination. After germination, thin the seedlings: retain 1 corn plant, 3 bitter bean plants, and 3 crested wheatgrass plants per pot. Continue to water regularly after thinning to maintain soil moisture. After 3 months of cultivation, harvest the plants and collect soil samples to determine soil nutrient content and salinity indicators.

[0044] 1.6 Results Analysis (1) Analysis of the fertilization effect of various material treatments on soda saline-alkali soil According to Table 2: After treatment with 1% D1 ​​biochar, the available potassium in the soil increased by 73.7% compared to the original soil.

[0045] After treatment with 2% D2 biochar, soil organic matter and available potassium increased by 31% and 167.7% respectively compared with the original soil.

[0046] After treatment with 1% D3 humus organic fertilizer, the available phosphorus and available potassium in the soil increased by 325.9% and 86.9% respectively compared with the original soil.

[0047] After treatment with 2% D4 humus organic fertilizer, the soil organic matter, available phosphorus, and available potassium all increased by 25.3%, 146.2%, and 154% respectively compared with the original soil, and the available nitrogen increased by 3%.

[0048] After treatment with D5 and D6 nano-mineral powders, the available potassium content increased by 22.2% and 21.7% respectively compared to the original soil.

[0049] After treatment with 1% D7 plant protein peptides, the available nitrogen, available phosphorus, and available potassium in the soil increased by 142.6%, 426.0%, and 24.3% respectively compared with the original soil.

[0050] After treatment with 2% D8 plant protein peptides, the available nitrogen, available phosphorus, and available potassium in the soil increased by 205.7%, 514.7%, and 38.2% respectively compared with the original soil.

[0051] After treatment with D9 and D10 desulfurized gypsum powder, only the available potassium in the soil increased, by 10.0% and 6.8% respectively compared with the original soil.

[0052] After treatment with 1% D11 commercial organic fertilizer, the available phosphorus and available potassium in the soil increased by 194.4% and 41.6% respectively compared with the original soil.

[0053] Treatment with 2% D12 commercial organic fertilizer increased available phosphorus and potassium in the soil by 251.2% and 48.7% respectively compared to the original soil.

[0054] In summary, all six materials, when applied individually, improved the nutrient content of soda-saline-alkali soils. However, only hydrothermal biochar and humus organic fertilizer increased soil organic matter content, while commercial organic fertilizer only increased the available nutrients phosphorus and potassium. Plant protein peptides significantly increased the content of available nitrogen, phosphorus, and potassium. Natural nano-mineral powder and desulfurized gypsum powder only increased the available potassium content of the soil.

[0055]

[0056] (2) The effects of various material treatments on the obstacle factors of soda saline-alkali soil According to Table 3: After treatment with D1, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 51.8%, 33.3%, and 26.5% respectively compared with the original soil, and the pH was reduced by 0.12 units.

[0057] After D2 treatment, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 68.5%, 37.9%, and 31.0% respectively compared with the original soil, the pH was reduced by 0.1 unit, and the sodium ion content was reduced by 12.6%.

[0058] After D3 treatment, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 57.4.0%, 20.2%, and 18.6% respectively compared with the original soil, the pH was reduced by 0.17 units, and the bicarbonate ion content was reduced by 26.8%.

[0059] After D4 treatment, the total salt content, alkalinity, and bicarbonate ion content of the various obstacle factors in the soda saline-alkali soil decreased by 42.6%, 21.4%, and 36.9% respectively compared with the original soil, and the pH decreased by 0.56 units, but the EC value did not change significantly.

[0060] After D5 treatment, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 55.6%, 37.4%, and 32.3% respectively compared with the original soil, the pH was reduced by 0.2 units, and the bicarbonate ion content was reduced by 16.4%.

[0061] After D6 treatment, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 53.7%, 26.3%, and 40.1% respectively compared with the original soil, the pH was reduced by 0.27 units, and the bicarbonate ion content was reduced by 22.3%.

[0062] After D7 treatment, the total salt content, alkalinity, EC value, and bicarbonate ion content of the soda saline-alkali soil decreased by 44.4%, 48.9%, 11.2%, and 38.4% respectively compared with the original soil, and the pH decreased by 0.72 units.

[0063] After D8 treatment, the total salt content, alkalinity, EC value, and bicarbonate ion content of the soda saline-alkali soil decreased by 27.8%, 66.1%, 9.7%, and 66.9% respectively compared with the original soil, and the pH decreased by 1.28 units.

[0064] After D9 treatment, the total salt content, alkalinity, and EC value of the soda saline-alkali soil decreased by 29.6%, 22.2%, and 20.2% respectively compared with the original soil, the pH decreased by 0.11 units, and the bicarbonate ion concentration increased by 4.9%.

[0065] After D10 treatment, the total salt content, alkalinity, EC value, and bicarbonate ion content of the soda saline-alkali soil decreased by 25.9%, 13.9%, 18.7%, and 3.3% respectively compared with the original soil, and the pH decreased by 0.11 units.

[0066] After D11 treatment, the total salt content, alkalinity, EC value, and bicarbonate ion content of the soda saline-alkali soil decreased by 25.9%, 13.6%, 3.3%, and 2.1% respectively compared with the original soil, and the pH decreased by 0.05 units.

[0067] After D12 treatment, the total salt content, alkalinity, and EC value of the soda saline-alkali soil decreased by 12.9%, 16.0%, and 9.8% respectively compared with the original soil, the pH decreased by 0.08 units, and the bicarbonate ion concentration increased by 7.4%.

[0068] In summary, the individual application of humus organic fertilizer, natural nano-mineral powder, and plant amino acid peptides reduced bicarbonate ions (a barrier factor in soda-alkali soils) by 16-66% and alkalinity by 20-66%, significantly better than treatments with desulfurized gypsum and commercial organic fertilizer. While the application of hydrothermal biochar did not reduce bicarbonate ion content, it significantly reduced total soil salinity, alkalinity, and EC value.

[0069]

[0070] 1.7 Conclusion Therefore, based on the considerations of being green and environmentally friendly without secondary pollution, as well as improving soil nutrients and reducing obstacle factors, this invention selects humus organic fertilizer, natural nano-mineral powder, plant amino acid peptides, and hydrothermal biochar as the basic materials for formula design.

[0071] Example 2: Experimental Design of a Composite Material Formulating a Specialized Composite Material for Soil Enrichment and Soda-Based Saline-Alkali Land Remediation 1. Test soil: The soil was collected from paddy fields in Da'an County, Baicheng City, Jilin Province. The soil pH was 9.54, alkalinity was 24.3%, and bicarbonate ion content was 1.22 g / kg. It is a typical severely soda saline-alkali soil. The basic soil nutrients included organic matter content of 12.7 g / kg, available nitrogen of 88.2 mg / kg, available phosphorus of 17.9 mg / kg, and available potassium of 156 mg / kg.

[0072] 2. Composite functional material formulation: The proportions of the formulation are expressed as a percentage by mass, and the formulation is shown in Table 4.

[0073]

[0074] 3. Formulation and Addition According to the formulation ratios in Table 4, organic fertilizer, natural nano-minerals, plant amino acid peptides, and hydrothermal biochar were weighed out and thoroughly mixed to prepare 12 formulation materials numbered F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, and F12. Several portions of 3 kg of soda-saline-alkali soil were weighed out, and each formulation material was added to the soil at 1% and 2% of the soil mass, respectively, and mixed thoroughly. The mixed soil samples were then placed in plastic culture pots (8 cm high, 6 cm in diameter) and labeled F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, and F12. A control group (FCK) was set up without any formulation materials.

[0075] 4. Sowing and daily management Evenly spray 500 ml of deionized water onto the surface of the test soil using a spray bottle, and let it stand for 3-5 days to equilibrate. When the surface soil moisture reaches about 20% and loosens, plant salt-tolerant plants such as *Sophora flavescens* and *Leymus chinensis* seeds, and observe the germination and growth of different treatments. Place the soil in a well-ventilated outdoor environment, and water it periodically as needed to keep the soil surface moist. After 3 months, harvest the plants and collect soil samples to determine the content of soil organic matter, nitrogen, phosphorus, potassium, and other nutrients, as well as salt and alkalinity indicators such as salinity and alkalinity.

[0076] 5. Results Analysis (1) Analysis of the fertilization effect of the formulation treatment on soda saline-alkali soil

[0077] According to Table 5: After treatment with the F1 formulation, the available phosphorus and available potassium in the soil increased by 244.7% and 110.9% respectively compared with the original soil.

[0078] After treatment with the F2 formulation, the available phosphorus and available potassium in the soil increased by 209.5% and 103.8% respectively compared with the original soil.

[0079] After treatment with the F3 formulation, the available phosphorus and available potassium in the soil increased by 207.8% and 100%, respectively, compared to the original soil.

[0080] After treatment with the F4 formula, the levels of soil organic matter, available phosphorus, and available potassium all increased by 11.6%, 289.9%, and 135.4% respectively compared to the original soil, while the increase in available nitrogen was not significant.

[0081] After treatment with the F5 formula, the soil organic matter, available phosphorus, and available potassium increased by 4.3%, 277.6%, and 121.6% respectively compared with the original soil.

[0082] After treatment with the F6 formulation, the soil organic matter, available phosphorus, and available potassium increased by 4.2%, 359.2%, and 123.1%, respectively, compared with the original soil.

[0083] After treatment with the F7 formula, the soil organic matter, available phosphorus, and available potassium increased by 32.3%, 506.0%, and 165.6% respectively compared with the original soil.

[0084] After treatment with the F8 formula, the soil organic matter, available phosphorus, and available potassium increased by 3.9%, 449.0%, and 197.9% respectively compared with the original soil.

[0085] After treatment with the F9 formula, the soil organic matter, available nitrogen, available phosphorus, and available potassium all increased by 5.5%, 31.4%, 447.3%, and 198.5% respectively compared with the original soil.

[0086] After treatment with the F10 formula, the soil organic matter, available nitrogen, available phosphorus, and available potassium all increased by 15.7%, 65.5%, 580.2%, and 183.0% respectively compared with the original soil.

[0087] After treatment with the F11 formula, the soil organic matter, available nitrogen, available phosphorus, and available potassium all increased by 18.1%, 16.9%, 519.8%, and 134.2% respectively compared with the original soil.

[0088] After treatment with the F12 formula, the soil organic matter, available nitrogen, available phosphorus, and available potassium all increased by 18.9%, 43.5%, 492.2%, and 207.5% respectively compared with the original soil.

[0089] In summary, when using formulations F9, F10, F11, and F12 at a concentration of 2%, not only can the organic matter content be increased, but the available nitrogen, phosphorus, and potassium content in the soil can also be significantly improved.

[0090] (2) Formula treatment to eliminate the effect of soda saline-alkali soil barrier factors

[0091] According to Table 6: After treatment with formula F1, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 59.3%, 37.0%, and 19.8% respectively compared with the original soil, and the pH was reduced by 0.2 units, but the reduction of bicarbonate ions was not significant.

[0092] After treatment with F2 formulation, the total salt content, alkalinity, and EC value of the various obstacle factors in the soda saline-alkali soil decreased by 53.7%, 31.3%, and 20.3% respectively compared with the original soil, and the pH decreased by 0.3 units, but the decrease in bicarbonate ions was not significant.

[0093] After treatment with the F3 formula, the total salt content, alkalinity, and EC value of the various obstacle factors in the soda saline-alkali soil decreased by 63.0%, 2.5%, and 19.8% respectively compared with the original soil, and the pH decreased by 0.3 units, but the decrease in bicarbonate ions was not significant.

[0094] After treatment with F4 formulation, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 63.0%, 22.6%, and 16.4% respectively compared with the original soil, the pH was reduced by 0.5 units, and the bicarbonate ion content was reduced by 17.2%.

[0095] After treatment with F5 formulation, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 59.3%, 22.2%, and 20.8% respectively compared with the original soil, the pH was reduced by 0.6 units, and the bicarbonate ion content was reduced by 25.4%.

[0096] After treatment with F6 formulation, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 66.7%, 31.3%, and 24.1% respectively compared with the original soil, the pH was reduced by 0.4 units, and the bicarbonate ion content was reduced by 32.0%.

[0097] After treatment with F7 formulation, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 42.6%, 35.0%, and 13.5% respectively compared with the original soil, the pH was reduced by 0.3 units, and the bicarbonate ion content was reduced by 19.7%.

[0098] After treatment with F8 formulation, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 59.3%, 32.5%, and 15.6% respectively compared with the original soil, the pH was reduced by 0.3 units, and the bicarbonate ion content was reduced by 7.4%.

[0099] After treatment with F9 formulation, the total salt content, alkalinity, and EC value of the soda saline-alkali soil were reduced by 50.0%, 12.8%, and 2.2% respectively compared with the original soil, the pH was reduced by 0.4 units, and the bicarbonate ion content was reduced by 34.4%.

[0100] After treatment with the F10 formula, the total salt content, alkalinity, and bicarbonate ion content of the various obstacle factors in the soda saline-alkali soil decreased by 33.3%, 23.9%, and 32.8% respectively compared with the original soil, and the pH decreased by 0.7 units.

[0101] After treatment with the F11 formula, the total salt content, alkalinity, and bicarbonate ion content of the various obstacle factors in the soda saline-alkali soil decreased by 48.1%, 15.6%, and 32.8% respectively compared with the original soil, and the pH decreased by 0.6 units.

[0102] After treatment with the F12 formula, the total salt content, alkalinity, and bicarbonate ion content of the various obstacle factors in the soda saline-alkali soil decreased by 50.0%, 38.3%, and 45.1% respectively compared with the original soil, and the pH decreased by 0.8 units.

[0103] In summary, when using formulations F9, F10, F11, and F12 at a concentration of 2%, the total salt content, alkalinity, bicarbonate ion concentration, and pH value of the soda saline-alkali soil barrier factors were significantly reduced.

[0104] (3) Conclusion In summary, when using formulations F9, F10, F11, and F12 at a concentration of 2%, not only can the organic matter content be increased, but the available nitrogen, phosphorus, and potassium content in the soil can also be significantly improved. The total salt content, alkalinity, bicarbonate ion content, and pH value of the soda saline-alkali soil barrier factors are all significantly reduced.

[0105] Example 3: Adaptability Study of Composite Functional Materials in Soda-Saline-Alkali Soils of Different Regions 1. Test soil: 1) The samples were collected from soda saline-alkali soil in abandoned land in Da'an County, Baicheng City, Jilin Province. The basic soil nutrients were: organic matter content 5.82 g / kg, available nitrogen 18.0 mg / kg, available phosphorus 12.6 mg / kg, available potassium 181 mg / kg, and soil micro-aggregate composition 61.90%. The total salt content was 3.6 g / kg, alkalinity was 53.1%, and pH value was 10.28.

[0106] 2) The soil samples were collected from soda-saline-alkali soil in Daqing City, Heilongjiang Province. The basic soil nutrients included organic matter content of 9.20 g / kg, available nitrogen of 21.8 mg / kg, available phosphorus of 23.5 mg / kg, available potassium of 179 mg / kg, and soil micro-aggregate composition of 88.17%. The carbonate ion content was 0.210 g / kg, bicarbonate ion content was 1.64 g / kg, total salt content was 3.6 g / kg, alkalinity was 102%, and pH value was 10.4.

[0107] 2. Test treatment: The F9 formula (humus organic fertilizer: natural nano-minerals: plant amino acid peptides: hydrothermal biochar = 4:0.25:0.25:1) was selected and added at a rate of 2%. Rapid treatment experiments were conducted on soda saline-alkali soils in different regions. The experimental treatments and their numbers are as follows.

[0108]

[0109] 3. Experiment Implementation: According to formula F9, weigh out humus organic fertilizer, natural nano-minerals, plant amino acid peptides, and hydrothermal biochar, and mix them thoroughly to prepare the formula materials. Weigh out 13 kg of soda saline-alkali soil from Da'an and Daqing, four portions of each. Add formula material F9 to the two different soda saline-alkali soils at a dosage of 2% of the soil mass and mix thoroughly. Then, put the mixed soil into plastic culture pots, and set up a control group without adding any formula materials, and label them as Nong 1, Nong 2, Nong 3, and Nong 4 according to Table 4.

[0110] Each pot was evenly watered with 4000ml of deionized water, and the water infiltration was observed during the treatment. After the first watering was completely infiltrated, the pot was left to stand for 1 week. 300ml of water was watered every two days, and samples were taken to measure the soil nutrient content, soil micro-aggregate composition, and salinity barrier index.

[0111] 4. Results Analysis:

[0112] As shown in Table 8, after one week of treatment with Formula 9, the organic matter, available nitrogen, available phosphorus, and available potassium in the Da'an soda-alkali soil increased by 204%, 1578%, 1622%, and 1220%, respectively. The soil micro-aggregate composition decreased to 36.02%, making it an ideal soil for planting (micro-aggregate composition accounts for 30%-40%). The pH value decreased from 10.28 to 8.86, a reduction of 1.42 units, the total salt content decreased by 22.2%, and the alkalinity decreased by 8 times.

[0113] After one week of treatment with Formula 9, the organic matter, available nitrogen, available phosphorus, and available potassium in Daqing's soda-saline-alkali soil increased by 148%, 372%, 1329%, and 833%, respectively. The soil micro-aggregate composition reached 37.42%, achieving ideal soil conditions for planting (this effect was confirmed by the normal emergence and growth of corn seedlings planted later). The pH value decreased by 0.4 units, the total salt content decreased by 22.2%, and the alkalinity decreased by 3.9 times.

[0114] 5. Conclusion The results of the cross-regional applicability test of Formula 9 (Da'an, Jilin / Daqing, Heilongjiang) showed that: 1) Soil microaggregates decreased from 62.96% to 36-37% within 7 days (ideal soil value is 30%-40%). 2) The alkalinity decreased by 3.9-8 times (from 102% to 26% in Daqing); 3) Soil organic matter increased by 148%-204%; 4) The availability of soil nutrients, including alkaline-available nitrogen, available phosphorus, and available potassium, was significantly increased; 5) Soil pH decreased by 0.4-1.42 units; 6) Soil total salt content decreased significantly.

[0115] The results show that the composite functional material provided by this invention can quickly eliminate the salinity and alkalinity barrier factors in soda saline-alkali soil, and simultaneously increase the soil organic matter and nutrient content.

[0116] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for treating soda-saline-alkali soil, characterized in that, Composite functional materials are applied to the soil; The composite functional material consists of the following components Composition: 4 parts by weight of humus organic fertilizer, 0.25 parts by weight of natural nano mineral powder, 0.25 parts by weight of plant amino acid peptides, and 1 part by weight of hydrothermal biochar. The humus-based organic fertilizer has the following characteristics: organic matter content 12-14 wt%, total nitrogen content 1.0-1.16 wt%, phosphorus content (based on P2O5) 3.0-3.15 wt%, and potassium content (based on K2O) 1.7-1.87 wt%. The natural nano-mineral powder has the following characteristics: calcium 0.54-0.56 wt%, magnesium 0.21-0.23 wt%, copper 0.00015-0.0002 wt%, iron 1.59-1.69 wt%, manganese 0.026-0.028 wt%, zinc 0.0055-0.006 wt%, and selenium 0.035-0.04 mg / kg; The plant amino acid peptides have the following characteristics: total nitrogen content 8.5-8.92 wt%, phosphorus content (based on P2O5) 5.0-5.14 wt%, potassium content (based on K2O) 6.0-6.5 wt%, organic matter content 75-83.8 wt%, free amino acid content 14-14.9 wt%, calcium content 1.0-1.1 wt%, magnesium content 0.55-0.64 wt%, sulfur content 1.28-1.38 wt%, copper content 0.02 wt%, iron content 0.02 wt%, and manganese content 0.02 wt%. The hydrothermal biochar has the following characteristics: specific surface area 620-802 m² 2 / g, total nitrogen content 0.9-0.994wt%, phosphorus content (based on P2O5) 1.5-1.58wt%, potassium content (based on K2O) 4.5-4.62wt%, calcium content 0.31-0.36wt%, magnesium content 0.30-0.35wt%, pH 4.5-5.06; The application rate of the composite functional material is 2% of the soil mass.

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