A straw resource utilization method for saline-alkali land treatment based on micro-aerobic aeration hydrolysis acidification

Abstract

The present application belongs to the technical field of agricultural waste resource and saline-alkali land improvement, and particularly relates to a straw resource management method for saline-alkali land based on micro-aerobic aeration hydrolysis acidification. The present application is based on the micro-aerobic aeration hydrolysis acidification process and the fermentation performance of the bacterial agent, so that the hydrolysis acidification process of the straw raw material is completed within a few days, and the pH of the generated acidification liquid can be stabilized between 4.0 and 5.5. After the hydrolysis acidification liquid and the straw residue are applied to the saline-alkali soil, the acidification liquid can directly react with the alkaline substances in the soil to rapidly reduce the pH value of the soil; the straw residue can be continuously and slowly decomposed to release nitrogen, phosphorus, potassium and other elements after being applied to the soil, thereby providing long-term nutrient supply for crop growth; the input organic matter can improve the soil aggregate structure and improve the soil water and fertilizer retention capacity, and the functional microorganisms after planting can continuously participate in the soil material circulation, thereby enhancing the soil buffering capacity and the salt-alkali resistance, so that the saline-alkali land management efficiency is high, the neutralization effect is rapid, the improvement effect is comprehensive and long-acting.

Description

Technical Field

[0001] This invention belongs to the field of agricultural waste resource utilization and saline-alkali land improvement technology, specifically involving a straw resource utilization method for saline-alkali land management based on micro-aerobic aeration hydrolysis acidification. Background Technology

[0002] Soil salinization has become one of the core challenges restricting sustainable agricultural development, not only leading to the degradation of arable land quality but also directly threatening food security. The high pH and high electrical conductivity of saline-alkali land disrupt soil aggregate structure, resulting in soil compaction and poor aeration. Simultaneously, excessive sodium and chloride ions inhibit nutrient absorption by crop roots, reducing nutrient availability and ultimately causing a decline in crop emergence rates. This poses a dual threat to agricultural production and the ecological environment. Meanwhile, the challenge of large-scale, high-value utilization of crop straw has become a prominent pain point in green agricultural development. Some regions have attempted methods such as direct straw return to the field and composting, but direct straw return suffers from slow degradation and competition for nutrients with crops, while composting faces limitations such as long fermentation cycles and high salt residues in the products, making it difficult to achieve efficient recycling of straw resources.

[0003] At present, the main technologies for improving saline-alkali land include the following: (1) Physical improvement technology is a traditional method to reduce salt content by changing the soil structure and water movement state of saline-alkali land. It mainly includes deep plowing and loosening of soil, replacement of soil with imported soil, underground drainage, and mulching to suppress salt. Deep tillage breaks up soil compaction through mechanical plowing, thereby enhancing soil aeration and promoting the evaporation of salts with water. However, this method has a short-term effect, requires repeated operations, and cannot fundamentally improve soil fertility. Soil replacement involves mixing non-saline-alkali soil with saline-alkali soil or directly replacing the surface saline-alkali soil with non-saline-alkali soil. This method can quickly reduce soil salt concentration, but it involves large-scale engineering, high costs, and can easily damage soil resources in other locations, making it unsuitable for large-scale saline-alkali land treatment. Underground drainage uses buried drainage networks to remove saline water from the soil by gravity, while lowering the groundwater level to inhibit salt return. However, underground pipes are easily blocked by soil particles, resulting in high maintenance costs and only removing salts. Mulching reduces soil moisture evaporation and inhibits salt accumulation on the surface by laying plastic films. However, the films are difficult to degrade, easily causing soil pollution, and do not replenish soil nutrients. The core limitation of physical improvement technology is that it only targets the single goal of reducing soil salinity and does not involve improving soil fertility. It also has disadvantages such as high cost and poor sustainability. (2) Chemical improvement technology is to add chemical agents to saline-alkali land to adjust soil pH, reduce salinity and improve soil structure. It mainly includes the application of calcium-based amendments, acid amendments and structural amendments. The working principle of calcium-based amendments is to exchange calcium ions with sodium ions in soil colloids, promote the leaching of sodium ions with water and reduce soil alkalinity. However, this type of agent is slow to take effect and requires a large amount of application, which is costly. Acid amendments can directly neutralize soil alkalinity and quickly reduce soil alkalinity. However, long-term application can easily lead to soil compaction, destroy the soil microbial community structure and cannot remove excessive salt in the soil. It needs to be used in conjunction with irrigation and salt leaching. Humic acid amendments can improve soil aggregate structure, enhance soil water and fertilizer retention capacity and help reduce salt damage. However, the improvement effect is not significant, the cost is high and it is difficult to promote on a large scale. The core limitation of chemical improvement technology is that it requires additional chemical agents, which is costly and can easily cause secondary pollution of soil. (3) Biological improvement technology uses plants, microorganisms or their metabolites to improve saline-alkali land, mainly including planting salt-tolerant plants, inoculating salt-tolerant microbial agents, and applying biological organic fertilizers.Salt-tolerant plant improvement involves absorbing soil salts through plant roots and secreting organic acids to regulate soil pH. Returning fallen leaves and branches to the field increases soil organic matter. However, this method has a long treatment cycle and is limited by climate and soil conditions. Salt-tolerant microbial agents produce organic acids and polysaccharides through microbial metabolism, neutralizing soil alkalinity while promoting nutrient absorption by crops. However, the establishment of microbial agents is greatly affected by environmental factors such as soil salinity, pH, and humidity, resulting in poor stability. Bio-organic fertilizer improvement involves composting and fermenting organic matter such as livestock manure and straw before application. The organic matter and microbial community in the fertilizer improve soil structure and regulate pH. However, traditional composting has a long fermentation cycle, and incomplete fermentation can easily produce harmful gases. Furthermore, the high salt content in compost products may exacerbate soil salinization if applied directly. The core limitations of biological improvement technologies lie in the long fermentation cycle, low degradation efficiency, and salt residue risk associated with traditional bio-organic fertilizers, as well as the slow and unstable effects of salt-tolerant plants and microorganisms.

[0004] Existing technologies for improving saline-alkali land using straw mainly involve methods such as straw carbonization and returning it to the field. Straw carbonization involves carbonizing straw at high temperatures to produce biochar for application. Biochar has characteristics such as high specific surface area, which can adsorb soil salts and improve the soil's water and fertilizer retention capacity. However, the carbonization process consumes a lot of energy, resulting in high costs and significant loss of straw organic matter during the carbonization process, leading to low resource utilization.

[0005] In summary, existing saline-alkali land improvement technologies share the following common problems: they have a single improvement objective and lack comprehensive synergistic effects; they are generally costly, which limits their large-scale promotion; they have negative environmental impacts during application and poor sustainability; and they have low improvement efficiency, poor effect stability, and are significantly constrained by external conditions.

[0006] Straw hydrolysis and acidification technology is a process that uses chemical or biological methods to decompose large organic molecules such as cellulose and hemicellulose in straw into smaller molecules such as reducing sugars and volatile fatty acids (VFAs). Currently, the core bottleneck of straw hydrolysis and acidification technology lies in the stubborn structure of lignocellulose in straw, making it difficult to degrade efficiently. To address this issue, current research has developed an efficient pretreatment system that improves the degradation efficiency of lignocellulose through the synergistic effects of physical, chemical, and biological methods. Furthermore, in some studies known to the inventors, when the dissolved oxygen concentration is controlled at a microaerobic condition of 0.5–2 mg / L, it can effectively inhibit the activity of methanogens and promote the proliferation of acidifying bacteria. Under these conditions, the yield of short-chain fatty acids can be increased by 30%–50% compared to anaerobic conditions. Therefore, microaerobic aeration hydrolysis and acidification technology can be applied to straw resource utilization; however, there are no reports on the application of microaerobic aeration hydrolysis and acidification technology for the treatment of straw in saline-alkali land remediation. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention provides the following technical solution.

[0008] This invention provides a method for the resource utilization of straw and the treatment of saline-alkali land based on microaerobic aeration hydrolysis acidification, comprising the following steps: The crushed crop straw is mixed with water and then subjected to micro-aerobic aeration hydrolysis and acidification treatment until the pH value of the hydrolysis and acidification system is 4.0~5.5, to obtain a straw acidification and fermentation mixture; the dissolved oxygen concentration in the hydrolysis and acidification system is 0.5~2.0 mg / L; During the microaerobic aeration hydrolysis acidification process, a compound microbial agent is added to the hydrolysis acidification system. The compound microbial agent includes Clostridium beyerii, Bacteroides polymorpha, and Lactobacillus acidophilus. The dosage of the compound microbial agent is 0.1% to 0.5% of the dry weight of the crop straw. The straw acidification and fermentation mixture is applied to saline-alkali land, and the application method includes a first application method and / or a second application method: The first application method includes the following steps: separating the straw acidification and fermentation mixture into solid and liquid components to obtain acidified liquid and straw residue; The acidifying solution is applied to saline-alkali land during irrigation, while the straw residue is applied to the surface of the saline-alkali land and then tilled; the application rate of the acidifying solution is 50-100 m³. 3 / hm 2 The application rate of the straw residue, based on dry weight, is 1-5 t / hm. 2 ; The second application method includes the following steps: applying the straw acidification and fermentation mixture to the surface of saline-alkali land and tilling it; the application rate of the straw acidification and fermentation mixture is 3~10 t / hm based on the dry weight of the straw. 2 .

[0009] Preferably, in the first application method, the irrigation method includes drip irrigation and / or sprinkler irrigation.

[0010] Preferably, the drip irrigation and sprinkler irrigation rates are 5~10 m / s and 5~10 m / s, respectively. 3 / hm 2 ·h.

[0011] Preferably, in the first application method and the second application method, the tillage depth is 15~30 cm, respectively.

[0012] Preferably, the viable count of the compound microbial agent is ≥1.0×10⁻⁶. 9 CFU / g; the live count ratio of Clostridium beyeris, Bacteroides polymorpha and Lactobacillus acidophilus is 1~3:1~3:0.5~2.

[0013] Preferably, the compound microbial agent is added at the beginning of the microaerobic aeration hydrolysis acidification treatment or 24 hours after the microaerobic aeration hydrolysis acidification treatment.

[0014] Preferably, the mass ratio of the crushed crop straw to the volume ratio of water is 1 g: (5~15) mL.

[0015] Preferably, the micro-aerobic aeration hydrolysis acidification treatment takes 3 to 10 days.

[0016] Preferably, the saline-alkali land includes slightly saline-alkali land and / or moderately saline-alkali land.

[0017] Preferably, the crop straw includes one or more of corn straw, wheat straw, soybean straw, cotton straw, and rapeseed straw.

[0018] Beneficial effects: This invention provides a method for the resource-based treatment of saline-alkali land using straw based on microaerobic aeration hydrolysis acidification. This invention utilizes the microaerobic aeration hydrolysis acidification process and the fermentation performance of microbial agents to complete the hydrolysis and acidification process of straw raw materials within several days. The resulting acidified liquid has a stable pH between 4.0 and 5.5. When the hydrolyzed acidified liquid and straw residue, or a mixture thereof, are applied to saline-alkali soil, the acidified liquid directly neutralizes the alkaline substances in the soil, rapidly reducing the soil pH. This method can precisely regulate the soil pH to remain stable within the suitable range for crop growth (6.0-7.5), demonstrating high treatment efficiency and rapid neutralization. Meanwhile, this invention not only provides a fast-acting acidifying liquid to achieve rapid neutralization of saline-alkali soil, but also simultaneously introduces abundant organic matter and functional microorganisms into the saline-alkali soil; after the straw residue is returned to the field, it can continuously and slowly decompose and release elements such as nitrogen, phosphorus, and potassium, providing long-term nutrient supply for crop growth; at the same time, the introduced organic matter can improve the soil aggregate structure and enhance the soil's water and fertilizer retention capacity, while the functional microorganisms after planting can continuously participate in the soil material cycle, enhancing the soil's buffering capacity and resistance to salinization. The improvement effect of saline-alkali land is comprehensive and long-lasting. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0020] Figure 1 The process flow diagrams for the straw pretreatment, hydrolysis acidification and microbial agent enhancement stages in Examples 1 and 2 are shown below. Figure 2 This is a process flow diagram of the saline-alkali land treatment route in Example 1; Figure 3 This is a process flow diagram of the saline-alkali land treatment route in Example 2. Detailed Implementation

[0021] This invention provides a method for the resource utilization of straw and the treatment of saline-alkali land based on microaerobic aeration hydrolysis acidification, comprising the following steps: The crushed crop straw is mixed with water and then subjected to micro-aerobic aeration hydrolysis and acidification treatment until the pH value of the hydrolysis and acidification system is 4.0~5.5, to obtain a straw acidification and fermentation mixture; the dissolved oxygen concentration in the hydrolysis and acidification system is 0.5~2.0 mg / L; During the microaerobic aeration hydrolysis acidification process, a compound microbial agent is added to the hydrolysis acidification system. The compound microbial agent includes Clostridium beyerii, Bacteroides polymorpha, and Lactobacillus acidophilus. The dosage of the compound microbial agent is 0.1% to 0.5% of the dry weight of the crop straw. The straw acidification and fermentation mixture is applied to saline-alkali land, and the application method includes a first application method and / or a second application method: The first application method includes the following steps: separating the straw acidification and fermentation mixture into solid and liquid components to obtain acidified liquid and straw residue; The acidifying solution is applied to saline-alkali land during irrigation, while the straw residue is applied to the surface of the saline-alkali land and then tilled; the application rate of the acidifying solution is 50-100 m³. 3 / hm 2 The application rate of the straw residue is 1~5 t / hm. 2 ; The second application method includes the following steps: applying the straw acidification and fermentation mixture to the surface of saline-alkali land and tilling it; the application rate of the straw acidification and fermentation mixture is 3~10 t / hm based on the dry weight of the straw. 2 .

[0022] In one embodiment, the present invention collects crop straw, removes impurities, and then crushes the straw to obtain crushed crop straw. In one embodiment, the crop straw can be one or more of, but not limited to, corn straw, wheat straw, soybean straw, cotton straw, and rapeseed straw. In one embodiment, the length of the crushed crop straw can be 1-5 cm, 2-4 cm, or more specifically 3-4 cm; crop straw within this length range can significantly increase the specific surface area of ​​the straw.

[0023] After obtaining pulverized crop straw, this invention mixes the pulverized crop straw with water and then performs microaerobic aeration hydrolysis and acidification treatment until the pH value of the hydrolysis and acidification system is 4.0~5.5, obtaining a straw acidification and fermentation mixture. As one embodiment, the mass ratio of the pulverized crop straw to the volume ratio of water is 1 g:(5~15) mL, or it can be 1 g:(8~10) mL. As one embodiment, the specific steps of the microaerobic aeration hydrolysis and acidification treatment are as follows: the pulverized crop straw is mixed with water and immersed in the hydrolysis and acidification reactor, while the microaerobic aeration system is started, and the dissolved oxygen concentration in the system is adjusted through the microaerobic aeration system. As one embodiment, the dissolved oxygen concentration in the hydrolysis and acidification system is 0.8~1.0 mg / L.

[0024] In this invention, a compound microbial agent is added to the hydrolysis and acidification system during the microaerobic aeration hydrolysis and acidification treatment process. As one embodiment, the compound microbial agent is added at the beginning of the microaerobic aeration hydrolysis and acidification treatment, or 24 hours after the treatment, or 48 hours after the treatment. Adding the compound microbial agent at the start of aeration can quickly initiate the hydrolysis and acidification process; adding the agent 24-48 hours after the start of aeration allows for effective functional supplementation in the initially formed acidified environment, increasing the targeted production of the target product. The compound microbial agent includes *Clostridium beyerii*, *Bacteroides polymorpha*, and *Lactobacillus acidophilus*, and the dosage of the compound microbial agent is 0.1%-0.5% of the dry weight of the crop straw. As another embodiment, the dosage of the compound microbial agent is 0.2%-0.4% of the dry weight of the crop straw, or 0.3%-0.4%. Adding a compound microbial agent to the hydrolysis acidification system during the microaerobic aeration hydrolysis acidification treatment can enhance the acidification efficiency of straw. As one embodiment, the viable count of the compound microbial agent is ≥1.0 × 10⁻⁶. 9 CFU / g; the viable count ratio of *Clostridium beyerei*, *Bacteroides polymorpha*, and *Lactobacillus acidophilus* is 1-3:1-3:0.5-2, or 2:2:1. In this invention, the composite microbial agent using *Clostridium beyerei*, *Bacteroides polymorpha*, and *Lactobacillus acidophilus* has the effect of efficient degradation and targeted acid production. This invention does not have specific limitations on the strain type and source of the *Clostridium beyerei*, *Bacteroides polymorpha*, and *Lactobacillus acidophilus*; commercially available strains or self-isolated strains are acceptable. As one embodiment, the microaerobic aeration hydrolysis acidification treatment process lasts for 3-10 days, during which the pH value of the hydrolysis acidification system is monitored in real time until the pH value stabilizes within the range of 4.0-5.5, resulting in a straw acidification fermentation mixture. In this invention, the acidified substances produced by stabilizing the hydrolysis acidification system within the range of 4.0-5.5 can efficiently neutralize soil alkalinity.

[0025] The present invention obtains a straw acidification and fermentation mixture, and applies the straw acidification and fermentation mixture to saline-alkali land. The application method includes a first application method and / or a second application method: The first application method includes the following steps: separating the straw acidification and fermentation mixture into solid and liquid components to obtain acidified liquid and straw residue; The acidifying solution is applied to saline-alkali land during irrigation, while the straw residue is applied to the surface of the saline-alkali land and then tilled; the application rate of the acidifying solution is 50-100 m³. 3 / hm 2 The application rate of the straw residue is 1~5 t / hm. 2 ; The second application method includes the following steps: applying the straw acidification and fermentation mixture to the surface of saline-alkali land and tilling it; the application rate of the straw acidification and fermentation mixture is 3~10 t / hm based on the dry weight of the straw. 2 .

[0026] As one implementation method, the solid-liquid separation can be achieved using a plate and frame filter press or a centrifuge. Specific parameters are not particularly limited; conventional parameters in the art can be used. In this invention, the main components of the acidification liquid include mixed acids, such as acetic acid and propionic acid, complex biomolecules, such as humic acids, microorganisms and their residues and metabolites, and extracellular polymeric substances (EPS). In this invention, the acidification liquid must be used immediately after preparation because the main acidic substances (such as acetic acid and propionic acid) are volatile fatty acids, and long-term storage will lead to a weakening of their effectiveness.

[0027] In one implementation method, the irrigation method includes drip irrigation and / or sprinkler irrigation. In one implementation method, the drip irrigation and sprinkler irrigation rates are 5-10 m / s, respectively. 3 / hm 2 •h, or 6~8 m 3 / hm 2 •h. As one embodiment, the amount of acidifying liquid applied is 75 m³. 3 / hm 2 The application rate of the straw residue, based on dry weight, is 3 t / hm. 2 In one implementation method, the tillage depth in both the first and second application methods is 15-30 cm, or 18-25 cm. Tillage ensures better mixing of straw residue or straw acidification fermentation mixture with saline-alkali soil.

[0028] In this invention, two application methods are applicable to different scenarios. The first application method enables precise and efficient application of the acidified liquid, but it requires liquid irrigation equipment for drip or sprinkler irrigation, making it more suitable for large-scale sites with irrigation conditions. The second application method has integrated procedures and is simple to operate, making it more suitable for small-scale or extensively managed plots with limited irrigation conditions.

[0029] In one embodiment, the saline-alkali land includes slightly saline-alkali land and / or moderately saline-alkali land.

[0030] Compared with existing technologies, this invention solves the core problems of existing saline-alkali land improvement technologies and straw resource utilization, specifically including: 1) By using micro-aeration hydrolysis acidification technology and compound microbial inoculation, the resistance structure of lignocellulose can be effectively broken down, increasing its bioavailability and thus converting it into the target product more efficiently. This overcomes the shortcomings of traditional straw treatment, such as slow degradation of lignocellulose, low conversion efficiency, and difficulty in efficiently converting it into functional materials for saline-alkali land improvement; 2) It provides a lower-cost and simpler technical solution suitable for the treatment of moderate to mild saline-alkali land, avoiding the high cost and secondary pollution problems of traditional alkaline amendments and chemical amendment technologies; 3) It achieves efficient synergy between straw resource utilization and saline-alkali land improvement. Through micro-aeration hydrolysis acidification technology, it can quickly neutralize soil alkalinity and reduce salt damage, while simultaneously replenishing soil organic matter and functional microorganisms.

[0031] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0032] The experimental materials and equipment used in the following examples are as follows: 1. Experimental materials: Straw raw material: Corn stalks commonly found in North China are selected, and after removing impurities, they are crushed to a length of 2 cm.

[0033] Compound microbial inoculant: composed of Clostridium beyerii ( Clostridium beijerinckii ), Bacteroides multiforme ( Bacteroides thetaiotaomicron ), Lactobacillus acidophilus ( Lactobacillus acidophilus It is prepared with live bacteria in a ratio of 2:2:1, and the total number of live bacteria is ≥1.0×10⁻⁶. 9 CFU / g; All three strains were obtained from the China General Microbiological Culture Collection Center: Clostridium beyerei (CGMCC 1.2127), Bacteroides multiforme (CGMCC 1.5132), and Lactobacillus acidophilus (CGMCC 1.1854).

[0034] Experimental saline-alkali soil: collected from a moderately saline-alkali farmland. The initial soil pH was 8.7, electrical conductivity was 3.2 mS / cm, alkalinity was 18.5%, and soil organic matter content was 6.2 g / kg.

[0035] 2. Experimental equipment The equipment required for the experiment includes: straw crusher, micro-aeration hydrolysis acidification reactor, centrifuge, straw return machine, rotary tiller, portable pH meter, conductivity meter, soil organic matter analyzer, and microbial viable cell counting incubator.

[0036] Example 1 A method for treating saline-alkali land based on microaerobic aeration hydrolysis and acidification of straw, wherein the process flow diagram of straw pretreatment, hydrolysis and acidification and microbial agent enhancement stages in steps 1 and 2 is as follows: Figure 1 As shown, the application path flowchart in step 3 is as follows: Figure 2 As shown. The specific steps are as follows: 1. Straw pretreatment: Take 10 kg of dry corn stalks, remove impurities, and then use a straw crusher to crush the straw to a length of 2 cm. Remove impurities and set aside.

[0037] 2. Hydrolysis Acidification and Microbial Agent Enhancement: Pretreated straw and water were mixed at a mass-to-volume ratio of 1:10 (g:mL) and immersed in a hydrolysis acidification reactor. Simultaneously, a micro-aeration system was activated to maintain the dissolved oxygen concentration at 1.0 mg / L. When starting the aeration device, 0.2% of the straw dry weight of the compound microbial agent was added, and the aeration reaction was continued for 7 days. After the reaction, the pH of the system stabilized at 4.8.

[0038] 3. Application Path: After solid-liquid separation of the straw acidification fermentation mixture obtained in step 2, return each mixture to the field. Use a plate and frame filter press or centrifuge to separate the solid and liquid components of the fermented mixture, obtaining acidified liquid and straw residue. The acidified liquid requires no additional treatment and can be directly applied to saline-alkali land through drip irrigation or sprinkler irrigation systems. Simultaneously, the separated straw residue is evenly spread on the surface of the saline-alkali soil using a straw returning machine, and then compacted into the soil using a rotary tiller. The specific steps are as follows: The experiment group and the blank control group were set up.

[0039] Application group on saline-alkali land: An area of ​​0.01 hm² was selected. 2 In the experimental saline-alkali soil plot, the acidified solution was administered via a drip irrigation system at a rate of 8 m... 3 / hm 2 The acidifying solution was applied uniformly at a rate of ·h, with a total application rate of 75 m³. 3 / hm 2Simultaneously, straw residue is spread on the soil surface using a straw returning machine, and then compacted into the soil layer to a depth of 15-25 cm by a rotary tiller. The dry basis application rate of straw residue is 3 t / hm². 2 .

[0040] Blank control group: An equal area of ​​saline-alkali soil was selected from the same plot, and no amendments were applied; only conventional tillage was carried out.

[0041] Soil physicochemical indicators were measured on the 7th, 30th and 90th day after application, and the results are shown in Table 1 below.

[0042] Table 1. Monitoring of the effect of saline-alkali land improvement over time in Example 1

[0043] Note: Compared with the control group, p <0.01 indicates a highly significant difference; represent p <0.05 indicates a significant difference; the same applies to the following table.

[0044] Table 1 shows that, compared with the blank control group without the application of amendment materials, the method of the present invention can effectively increase the pH value of the soil, reduce the electrical conductivity and alkalinity of saline-alkali soil, increase the soil organic matter content and the number of viable soil microorganisms, and still have good effects within 90 days after application, with long-lasting improvement effect.

[0045] Example 2 A method for treating saline-alkali land based on microaerobic aeration hydrolysis and acidification of straw, wherein the process flow diagram of straw pretreatment, hydrolysis and acidification and microbial agent enhancement stages in steps 1 and 2 is as follows: Figure 1 As shown, the application path flowchart in step 3 is as follows: Figure 3 As shown. The specific steps are as follows: 1. Straw pretreatment: Take 12 kg of dry corn stalks, remove impurities, and then use a straw crusher to crush the straw to a length of 2 cm. Remove impurities and set aside.

[0046] 2. Hydrolysis Acidification and Microbial Agent Enhancement: Pretreated straw and water were mixed at a mass-to-volume ratio of 1:8 (g:mL) and immersed in a hydrolysis acidification reactor. Simultaneously, a micro-aeration system was activated to maintain the dissolved oxygen concentration at 1.0 mg / L. When starting the aeration device, 0.2% of the straw dry weight of the compound microbial agent was added, and the aeration reaction was continued for 7 days. After the reaction, the pH of the system stabilized at 5.0.

[0047] 3. Application Path: The acidified liquid obtained in step 2 is co-returned to the field with straw residue (i.e., the straw acidification fermentation mixture). This application path does not require solid-liquid separation; the fermented acidified liquid and straw residue mixture are directly and evenly applied to the saline-alkali land using a straw returning machine. After application, a rotary tiller is used to compact the mixture to a depth that ensures thorough mixing with the soil. Specific steps are as follows: The experiment group was set up with a saline-alkali land application group and a conventional improvement control group.

[0048] Application group on saline-alkali land: An area of ​​0.01 hm² was selected. 2 In the experimental saline-alkali soil plot, the acidified solution was administered via a drip irrigation system at a rate of 8 m... 3 / hm 2 The mixture was applied uniformly at a rate of h, with a total dry basis application rate of 4 t / hm. 2 The material is then compacted by a rotary tiller to a soil layer of 15-25 cm to ensure thorough mixing with the soil.

[0049] Conventional Improvement Control Group: An equal area of ​​saline-alkali soil from the same batch was selected and improved using traditional chemical methods, applying ferrous sulfate amendment (purchased from Shenzhen Changlong Technology Co., Ltd.) at a rate of 10 t / hm². 2 .

[0050] Soil physicochemical indicators were measured on the 7th, 30th and 90th day after application, and the results are shown in Table 2 below.

[0051] Table 2. Monitoring of the effect of saline-alkali land improvement over time in Example 2.

[0052] As shown in Table 2, compared with traditional chemical improvement methods, the method described in this invention can effectively increase the pH value of the soil, reduce the electrical conductivity and alkalinity of saline-alkali soil, increase the organic matter content and buffer capacity of the soil, and still have good effects within 90 days after application, with long-lasting improvement effect.

[0053] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for the resource utilization of straw and saline-alkali land management based on microaerobic aeration hydrolysis acidification, characterized in that, Includes the following steps: The crushed crop straw is mixed with water and then subjected to micro-aerobic aeration hydrolysis and acidification treatment until the pH value of the hydrolysis and acidification system is 4.0~5.5, to obtain a straw acidification and fermentation mixture; the dissolved oxygen concentration in the hydrolysis and acidification system is 0.5~2.0 mg / L; During the microaerobic aeration hydrolysis acidification process, a compound microbial agent is added to the hydrolysis acidification system. The compound microbial agent includes *Clostridium beyerii* (…). Clostridium beijerinckii ), Bacteroides multiforme ( Bacteroides thetaiotaomicron ) and Lactobacillus acidophilus ( Lactobacillus acidophilus The dosage of the compound microbial agent is 0.1% to 0.5% of the dry weight of crop straw. The straw acidification and fermentation mixture is applied to saline-alkali land, and the application method includes a first application method and / or a second application method: The first application method includes the following steps: separating the straw acidification and fermentation mixture into solid and liquid components to obtain acidified liquid and straw residue; The acidifying solution is applied to saline-alkali land during irrigation, while the straw residue is applied to the surface of the saline-alkali land and then tilled; the application rate of the acidifying solution is 50-100 m³. 3 / hm 2 The application rate of the straw residue, based on dry weight, is 1-5 t / hm. 2 ; The second application method includes the following steps: applying the straw acidification and fermentation mixture to the surface of saline-alkali land and tilling it; the application rate of the straw acidification and fermentation mixture is 3~10 t / hm based on the dry weight of the straw. 2 .

2. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 1, characterized in that, In the first application method, the irrigation method includes drip irrigation and / or sprinkler irrigation.

3. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 2, characterized in that, The drip irrigation and sprinkler irrigation rates are 5~10 m / s, respectively. 3 / hm 2 ·h.

4. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 1, characterized in that, In the first application method and the second application method, the tillage depth is 15~30 cm, respectively.

5. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 1, characterized in that, The viable count of the compound microbial agent is ≥1.0×10⁻⁶. 9 CFU / g; the live count ratio of Clostridium beyeris, Bacteroides polymorpha and Lactobacillus acidophilus is 1~3:1~3:0.5~2.

6. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 1 or 5, characterized in that, The compound microbial agent is added at the beginning of the microaerobic aeration hydrolysis acidification treatment or 24 hours after the microaerobic aeration hydrolysis acidification treatment.

7. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 1, characterized in that, The mass ratio of the crushed crop straw to the volume ratio of water is 1 g: (5~15) mL.

8. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 1, characterized in that, The micro-aerobic aeration hydrolysis acidification treatment takes 3 to 10 days.

9. The method for treating saline-alkali land based on straw resource utilization through microaerobic aeration and hydrolysis acidification according to claim 1, characterized in that, The saline-alkali land includes slightly saline-alkali land and / or moderately saline-alkali land.

10. The method for straw resource utilization and saline-alkali land management based on microaerobic aeration hydrolysis acidification according to claim 1, characterized in that, The crop straw includes one or more of the following: corn straw, wheat straw, soybean straw, cotton straw, and rapeseed straw.

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