Microbial directional activator, functional organic fertilizer, and preparation method and application thereof

Abstract

The application discloses a kind of microbial directional activator, functional organic fertilizer and its preparation method and application, belong to saline-alkali soil improvement technical field.The microbial directional activator includes by total mass:trehalose 18.0%-28.6%, betaine 8.5%-16.0%, spermidine 1.0%-2.6%, salicylic acid 0.2%-1.0%, potassium fulvate 13.3%-36.7%, sodium lignosulfonate 13.3%-36.7%, ferrous sulfate 0.2%-0.8%, zinc sulfate 0.1%-0.5%, and the balance is water.The application uses the microbial directional activator to prepare activated microbial bacteria liquid, and uses the activated microbial bacteria liquid to obtain functional organic fertilizer.The functional organic fertilizer of the application can reduce the pH and total salt content of saline-alkali soil, and improve the emergence rate and yield of crops.

Description

Technical Field

[0001] This invention belongs to the field of saline-alkali soil improvement technology, specifically a microbial targeted activator, a functional organic fertilizer, its preparation method and application. Background Technology

[0002] Salinization is one of the major obstacles to the sustainable development of agriculture in arid and semi-arid regions. High pH, ​​high salinity, and physical compaction severely affect crop growth. Meanwhile, agricultural production generates a large amount of organic solid waste annually, such as crop straw, fruit pomace, and livestock manure. Improper treatment of this waste not only wastes resources but also causes environmental pollution. Converting agricultural waste into organic fertilizer through bioconversion for saline-alkali land remediation is considered a potential approach that balances resource recycling and ecological improvement. However, existing technologies still face many insurmountable technical bottlenecks in practical applications.

[0003] In existing technologies, the preparation of organic fertilizers for saline-alkali land improvement mainly relies on conventional aerobic composting processes. This process has the following major drawbacks. First, during conventional composting, nitrogen-containing organic matter undergoes a violent ammoniation reaction, resulting in the matured products at the end of fermentation being weakly alkaline or alkaline. Applying such organic fertilizers to severely saline-alkali land with a pH value as high as 9.0 or above not only fails to effectively neutralize the soil alkalinity but may also exacerbate the alkalization, deviating from the original purpose of land improvement. To address this issue, the industry typically adds chemical acids such as sulfuric acid and phosphoric acid to the product after composting for acidification. However, this significantly increases production costs and easily disrupts the original micro-ecological balance of the compost, causing secondary pollution. Secondly, in traditional composting processes, lignocellulosic raw materials (such as cotton stalks) are difficult to degrade. To reach the maturity standard, it is often necessary to maintain a high temperature period for several weeks, which causes the organic carbon in the material to be over-mineralized into greenhouse gases such as carbon dioxide and methane. Nitrogen is volatilized in large quantities in the form of ammonia and nitrous oxide, resulting in serious nutrient loss and odor pollution. The final product has a low carbon and nitrogen retention rate and insufficient release of available phosphorus and potassium, making it difficult to provide lasting fertility support in barren saline-alkali land.

[0004] On the other hand, most commercially available EM (Effective Microorganisms) agents are designed for screening in conventional environments and lack adaptability to extreme habitats such as high salinity and alkalinity. Conventional methods of propagation with brown sugar water primarily increase the number of bacteria, failing to effectively improve their salt and alkali tolerance. Exogenous strains are easily inactivated by osmotic pressure shocks when introduced into saline-alkali soils. Furthermore, conventional activation methods struggle to stably enhance the ability of bacteria to secrete extracellular polymers (EPS), resulting in limited content of high-molecular-weight colloids in compost products that can be used to aggregate soil particles and alleviate salt crusting. Re-screening and acclimatizing halophilic and alkali-loving strains from extreme environments presents significant challenges, including long research and development cycles, high fermentation costs, and difficulties in industrialization.

[0005] Therefore, how to prepare functional organic fertilizer with acidity, high colloidal content and high stress resistance in situ through the activation of conventional microbial communities to salt and alkali tolerance and the regulation of composting process, without relying on chemical acidification and screening of extreme microbial species, in order to achieve efficient restoration of saline-alkali land, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a microbial targeted activator that can improve the stress resistance and gel production capacity of conventional microbial communities, and enrich organic acids and extracellular polymers in situ by combining secondary inoculation during the cooling period and microaerobic regulation process.

[0007] Another objective of this invention is to provide a functional organic fertilizer that can reduce the pH and total salt content of saline-alkali soils and improve crop emergence rate and yield.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a microbial targeted activator, comprising the following components by total mass: trehalose 18.0%-28.6%, betaine 8.5%-16.0%, spermidine 1.0%-2.6%, salicylic acid 0.2%-1.0%, potassium humate 13.3%-36.7%, sodium lignosulfonate 13.3%-36.7%, ferrous sulfate 0.2%-0.8%, zinc sulfate 0.1%-0.5%, with the balance being water, and the sum of the above components and water being 100%.

[0009] Preferably, the mass ratio of trehalose to betaine is (1.5-2.5):1; the mass ratio of spermidine to salicylic acid is (2-5):1; and the mass ratio of potassium humate to sodium lignosulfonate is (1-2):(1-2).

[0010] This invention also provides a method for preparing activated microbial bacterial solution, comprising the following steps: Mix the EM bacterial agent and the microbial directional activator at a mass ratio of 1:(8-10), and inoculate them into slightly saline water to construct an activation system; activate the activation system by shaking at 28-35℃ and 120-180rpm for 24-36 hours to obtain an activated microbial bacterial solution.

[0011] Preferably, the slightly saline water contains 2.0%-4.0% NaCl.

[0012] This invention also provides a method for preparing functional organic fertilizer, comprising the following steps: After the agricultural solid waste substrate is mixed, the initial C / N ratio and moisture content are adjusted. In the early stage of pile construction, the activated microbial liquid prepared by the preparation method is inoculated at 2-3% of the pile mass for aerobic fermentation. Once the temperature of the pile has naturally cooled to below 45°C, spray 3-5% of the activated microbial solution to stabilize the oxygen volume concentration inside the pile at 3.0%-8.0%, and continue fermentation for 15-20 days to obtain functional organic fertilizer.

[0013] Preferably, the oxygen volume concentration inside the pile is adjusted by reducing the turning frequency or controlling the ventilation volume.

[0014] Preferably, the agricultural solid waste substrate comprises, by weight percentage: 55%-65% fruit pomace, 20%-30% crushed cotton stalks, and 10%-20% livestock and poultry manure.

[0015] Preferably, the pomace is tomato peel pomace.

[0016] The present invention also provides a functional organic fertilizer prepared by the preparation method described above.

[0017] The present invention also provides an application of the aforementioned functional organic fertilizer in the preparation of a saline-alkali soil conditioner.

[0018] Compared with the prior art, the present invention has the following advantages: (1) This invention uses a specific ratio of spermidine and salicylic acid as microbial metabolism-inducing components to promote the expression of extracellular polysaccharide synthesis-related genes (such as epsA) in conventional EM bacterial communities. Under 3.0% brackish water stress, the activity of cellulase in the bacterial community is increased by nearly 3 times, the yield of extracellular polymeric substances (EPS) is increased by 6 times (to 42.3 g / L), and the survival rate in high-salt environments is increased to over 88%. Moreover, the activated phenotype maintains high stress resistance and gum production capacity during continuous subculturing. This technology overcomes the shortcomings of existing bacterial agents that mainly increase the number of bacteria but fail to improve stress resistance, and achieves the transformation of conventional bacterial communities into functional phenotypes with high stress resistance and high gum production at low cost.

[0019] (2) This invention constructs a composting process of "secondary inoculation during cooling period + microaerobic regulation". The activating agent extends the high-temperature period (>55℃) to 13-16 days in the early stage of composting, promoting the decomposition of lignocellulose. After switching to a microaerobic environment during the cooling period, it guides the adjustment of the metabolic direction of the microbial community, resulting in a significant increase in the total organic acids (135.4 g / kg) and EPS colloids (85.6 g / kg) compared to conventional composting. The acidic environment reduces NH3 emissions by 60.3%, increases total nitrogen retention by 25.9%, and promotes the conversion of total phosphorus and total potassium into available phosphorus (8.60 g / kg) and readily available potassium (18.50 g / kg). This process helps to improve the problem of weakly alkaline products and significant carbon and nitrogen loss in traditional composting, achieving synergy between waste resource utilization and targeted remediation of saline-alkali land.

[0020] (3) In severely saline-alkali cotton fields, when the application rate of the functional organic fertilizer of this invention is 300 kg / mu, the bio-derived organic acid reduces the rhizosphere pH from 9.10 to 8.05, the EPS polysaccharide increases the proportion of >0.25 mm water-stable aggregates to 42.8%, the total salt content decreases to 0.55%, and the bulk density decreases to 1.24 g / cm³. 3 This results in a synergistic improvement effect of chemical alkali reduction and physical sodium removal. Cotton emergence rate increased from 48.5% to 94.5%, and seed cotton yield reached 438.5 kg / mu, an increase of 94.5%. The marginal effect diminishes after exceeding 300 kg / mu, indicating that this invention can achieve good saline-alkali land improvement effects with relatively low application rates, combining ecological restoration with economic benefits. Attached Figure Description

[0021] Figure 1 This is a graph showing the temperature change over time for different treatment groups in Embodiment 8 of the present invention.

[0022] Figure 2 This is a graph showing the change of seed germination index (GI) over time in different treatment groups in Example 8 of the present invention.

[0023] Figure 3 This is a graph showing the pH change over time in different treatment groups in Example 8 of the present invention.

[0024] Figure 4 This is a comparison chart of gas emissions from different treatment groups in Embodiment 8 of the present invention. In the chart, a represents CO2 emissions, b represents CH4 emissions, c represents N2O emissions, d represents NH3 emissions, and e represents H2S emissions.

[0025] Figure 5 The effect of organic fertilizer on the restoration of the physicochemical properties of severely saline-alkali soil: Figure a shows the effect of organic fertilizer application on the pH of plant rhizosphere, b shows the effect of organic fertilizer application on the total salt content of the topsoil, c shows the effect of organic fertilizer application on the proportion of soil aggregates >0.25mm, and d shows the effect of organic fertilizer application on soil bulk density.

[0026] Figure 6 The figure shows the effects of organic fertilizer on cotton emergence and yield in saline-alkali land. Figure a represents the effect of organic fertilizer application on cotton emergence rate, b represents the effect of organic fertilizer application on cotton root dry weight, c represents the effect of organic fertilizer application on seed cotton yield, and d represents the yield increase of organic fertilizer application compared to control (CK). Detailed Implementation

[0027] This invention provides a microbial targeted activator, which preferably comprises the following components by total mass: trehalose 18.0%-28.6%, betaine 8.5%-16.0%, spermidine 1.0%-2.6%, salicylic acid 0.2%-1.0%, potassium humate 13.3%-36.7%, sodium lignosulfonate 13.3%-36.7%, ferrous sulfate 0.2%-0.8%, zinc sulfate 0.1%-0.5%, with the balance being water, and the sum of the above components and water is 100%. More preferably, it comprises the following components: trehalose 20.0%-26.7%, betaine 10.0%-13.3%, spermidine 1.14%-2.28%, salicylic acid 0.36%-0.72%, potassium humate 20.0%-27.5%, sodium lignosulfonate 20.0%-27.5%, ferrous sulfate 0.3%-0.7%, zinc sulfate 0.15%-0.4%, with the balance being water. Specifically, the amount of trehalose can be 18.0%, 19.0%, 20.0%, 21.0%, 22.0%, 23.33%, 24.0%, 25.0%, 26.0%, 27.0%, 28.0%, or 28.6%; the amount of betaine can be 8.5%, 9.0%, 10.0%, 11.0%, 11.67%, 12.0%, 13.0%, 14.0%, 15.0%, or 16.0%; the amount of spermidine can be 1.0%, 1.14%, 1.2%, 1.3%, 1.4%, 1.52%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, or 2.6%; and the amount of salicylic acid can be 0.2%, 0.3%, 0.36%, 0.4%, 0.48%, 0.5%, 0.6%, 0.7%, or 0.72%. The dosage of potassium humate can be 13.3%, 15.0%, 18.0%, 20.0%, 22.0%, 25.0%, 27.5%, 30.0%, 33.0%, 35.0%, or 36.7%; the dosage of sodium lignosulfonate can be 13.3%, 15.0%, 18.0%, 20.0%, 22.0%, 25.0%, 27.5%, 30.0%, 33.0%, 35.0%, or 36.7%; the dosage of ferrous sulfate can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or 0.8%; the dosage of zinc sulfate can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%; the remainder is made up with water.

[0028] In the microbial targeted activator provided by this invention, the proportional relationship of the internal components of each functional group has a significant impact on its targeted activation effect. Specifically, the preferred mass ratio of trehalose to betaine is (1.5-2.5):1; more preferably, the mass ratio of trehalose to betaine is 2:1, at which point the mass percentages of the two in the activator are 23.33% and 11.67%, respectively, achieving a better synergistic effect of extracellular vitreous protection and intracellular osmotic pressure balance. The preferred mass ratio of spermidine to salicylic acid is (2-5):1; more preferably, the mass ratio of spermidine to salicylic acid is 3:1, at which point the mass percentages of spermidine and salicylic acid are 1.52% and 0.48%, respectively, which can promote the expression of cellulase and polysaccharide-related genes while avoiding excessive stress on the cells. The preferred mass ratio of potassium humate to sodium lignin sulfonate is 1:1, at which point the mass percentages of both in the activator are 25.0%, achieving a synergistic effect of electrostatic shielding and surface adsorption, while providing a balanced carbon source supply for the cells.

[0029] This invention also provides a method for preparing activated microbial bacterial solution, comprising the following steps: Mix the EM bacterial agent and the microbial directional activator at a mass ratio of 1:(8-10), and inoculate them into slightly saline water to construct an activation system; activate the activation system by shaking at 28-35℃ and 120-180rpm for 24-36 hours to obtain an activated microbial bacterial solution.

[0030] In a specific embodiment of the present invention, the method for preparing the activated microbial bacterial solution provided by the present invention is carried out according to the following steps. First, commercially available EM bacterial agent and the above-mentioned microbial targeted activator are mixed at a mass ratio of 1:8-1:10, wherein the EM bacterial agent can be any commercially available agricultural product containing a complex microbial community such as Bacillus subtilis, Lactobacillus acidophilus, and Saccharomyces cerevisiae, with an effective viable count ≥2.0×10⁻⁶. 8CFU / mL. The mixed bacterial agent-activator system is inoculated into slightly brackish water to construct the activation system. The preferred mass ratio of bacterial agent to activator is 1:8, at which point the concentration of osmotic pressure protection substances and induction signals provided by the activator can achieve optimal matching with the subsequent salt stress intensity. The slightly brackish water contains sodium chloride, and its concentration can be selected in the range of 2.0% to 4.0%, preferably 3.0%. This concentration can create a moderate adversity that disrupts cell homeostasis and triggers defense mechanisms, without causing mass cell death due to excessive salt. The solid-liquid ratio at inoculation (i.e., the mass ratio of the bacterial agent-activator mixture to the slightly brackish water) is usually controlled between 1:15 and 1:25, preferably 1:20, to ensure that the cells obtain sufficient nutrients and dissolved oxygen. The constructed activation system was placed in a constant-temperature shaker for oscillation culture. The temperature was controlled between 28℃ and 35℃, preferably 30℃. This temperature range is conducive to the reconstruction of metabolic enzymes and the activation of defense signaling pathways within the bacteria. The shaker speed was controlled between 120 rpm and 180 rpm, preferably 150 rpm. This speed ensures the supply of dissolved oxygen in the system to meet the metabolic needs of aerobic bacteria, while avoiding excessive shear force that could damage newly synthesized extracellular polymers. The activation time is generally 24 to 36 hours, preferably 30 hours. At this time, the metabolic flow of the bacterial community has completely shifted from cell proliferation to the large-scale synthesis of extracellular polymers and organic acids. Under the above preferred conditions (mass ratio 1:8, NaCl concentration 3.0%, temperature 30℃, shaker 150 rpm, time 30 hours), the activated bacterial solution exhibits a highly viscous state, and under a microscope, a large number of bacterial cells can be observed to be coated with a thick layer of extracellular polysaccharides. The activated bacterial solution showed a survival rate of over 88.6% under extreme salt stress of 5.0% NaCl, an extracellular polymeric substance yield of 42.3 g / L, and a cellulase activity of 125.6 U / mL. In contrast, the unactivated original EM bacterial solution had a survival rate of less than 10% and an extracellular polymeric substance yield of less than 3 g / L under the same salt stress.

[0031] This invention also provides a method for preparing functional organic fertilizer, comprising the following steps: After the agricultural solid waste substrate is mixed, the initial C / N ratio and moisture content are adjusted. In the early stage of pile construction, the activated microbial liquid prepared by the preparation method is inoculated at 2-3% of the pile mass for aerobic fermentation. Once the temperature of the pile has naturally cooled to below 45°C, spray 3-5% of the activated microbial solution to stabilize the oxygen volume concentration inside the pile at 3.0%-8.0%, and continue fermentation for 15-20 days to obtain functional organic fertilizer.

[0032] In a specific embodiment of the present invention, the functional organic fertilizer preparation method provided by the present invention adopts a composting process combining secondary inoculation during the cooling period and micro-aerobic regulation, specifically carried out according to the following steps. First, agricultural solid waste substrate is prepared, which typically includes fruit pomace (such as tomato peel pomace), lignocellulosic waste (such as crushed cotton stalks), and livestock and poultry manure (such as cow and sheep manure), which can be mixed in a mass percentage ratio of 55%-65%, 20%-30%, and 10%-20%. The initial carbon-nitrogen ratio (C / N ratio) of the prepared mixture is adjusted to 25:1-30:1, preferably 28:1, and the moisture content is adjusted to 55%-60% to ensure a suitable environment for microbial growth and reproduction. In the initial stage of composting, 2%-3% of the total mass (wet weight) of the compost is inoculated with the activated microbial liquid prepared by the above preparation method. The inoculation method is to spray evenly and stir to ensure full contact with the material, followed by conventional aerobic fermentation. Because the activated bacterial solution has high cellulase activity, the pile can rapidly heat up to above 55℃ within 24-48 hours, and this high-temperature period above 55℃ can be maintained for 13-16 days. This not only effectively kills pathogens and weed seeds but also promotes the decomposition of the lignin-hemicellulose network structure in raw materials such as cotton stalks. When the pile temperature naturally cools to below 45℃ (usually around day 15-20 of fermentation), a second supplementary spray is performed, with an inoculation amount of 3%-5% of the pile mass, preferably 4%. After this inoculation, microaerobic regulation is implemented. Specifically, the turning frequency is reduced to once every 5-7 days, or the oxygen volume concentration inside the pile is stabilized between 3.0%-8.0%, preferably 5.0%, by controlling the ventilation equipment. Under microaerobic conditions, the monosaccharides produced in the early degradation stage can be converted into organic acids by facultative anaerobic bacteria such as lactic acid bacteria and yeast. Simultaneously, Bacillus secretes extracellular polymeric substances (EPS), causing the pile pH to drop from nearly 8.0 in the early stage to 5.5-6.5, preferably reaching 5.80. Continue fermentation for 15-20 days, with a total fermentation cycle of approximately 35-45 days, to obtain functional organic fertilizer. The product contains up to 135.4 g / kg of total organic acids, 85.6 g / kg of EPS, and over 218 g / kg of humus. The content of available phosphorus and readily available potassium is increased by more than 45% compared to conventional compost.

[0033] In a specific embodiment of the present invention, the compatibility of the agricultural solid waste substrate is crucial to the subsequent directional acid and gum production effect of composting. By mass percentage, fruit pomace accounts for 55%-65%, preferably tomato peel pomace, which is weakly acidic and rich in soluble sugars and pectin, providing easily degradable carbon sources for microorganisms and promoting organic acid production; crushed cotton stalks account for 20%-30%, whose high lignin content is dissociated under the action of highly efficient cellulase in the activated microbial agent, providing structural support and a slow-release carbon source for the compost pile; livestock and poultry manure accounts for 10%-20%, used to adjust the initial carbon-nitrogen ratio and supplement nitrogen sources. The combination of these three components allows the initial C / N ratio to be controlled at 25:1-30:1, with a moisture content of 55%-60%. When tomato peel pomace is used, its inherent organic acids and pectin can synergistically enhance the later micro-aerobic fermentation, further reducing the pH of the compost products and increasing the yield of extracellular polymers.

[0034] The present invention also provides a functional organic fertilizer prepared by the preparation method described above.

[0035] The present invention also provides an application of the aforementioned functional organic fertilizer in the preparation of a saline-alkali soil conditioner.

[0036] The present invention also provides an application of the aforementioned functional organic fertilizer in increasing crop yields in saline-alkali land.

[0037] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0038] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available products.

[0039] Example 1 A microbial targeted activator, based on the total mass of the microbial targeted activator, comprises the following components: trehalose 23.33%, betaine 11.67%, spermidine 1.52%, salicylic acid 0.48%, potassium humate 25.0%, sodium lignosulfonate 25.0%, ferrous sulfate 0.5%, zinc sulfate 0.2%, with the balance being deionized water to bring the total to 100%.

[0040] Example 2 A microbial targeted activator, based on the total mass of the microbial targeted activator, comprises the following components: trehalose 20.0%, betaine 10.0%, spermidine 1.14%, salicylic acid 0.36%, potassium humate 20.0%, sodium lignosulfonate 20.0%, ferrous sulfate 0.5%, zinc sulfate 0.2%, with the balance being deionized water to bring the total to 100%.

[0041] Example 3 A microbial targeted activator, based on the total mass of the microbial targeted activator, comprises the following components: trehalose 26.67%, betaine 13.33%, spermidine 2.28%, salicylic acid 0.72%, potassium humate 27.5%, sodium lignosulfonate 27.5%, ferrous sulfate 0.5%, zinc sulfate 0.2%, with the balance being deionized water to bring the total to 100%.

[0042] Example 4 A method for preparing activated microbial bacterial solution includes the following steps: Commercially available EM bacterial agent (purchased from Anmuyu Biotechnology Co., Ltd., containing Bacillus subtilis, Lactobacillus acidophilus, and Saccharomyces cerevisiae, with an effective viable count ≥ 2.0 × 10⁻⁶) is used. 8 The microbial directional activator (CFU / mL) was mixed with the microbial activator described in Example 1 at a mass ratio of 1:8, and inoculated into slightly saline water containing 3.0% NaCl, with a solid-liquid ratio of 1:20 to construct an activation system. The activation system was placed in a constant temperature shaker and activated by shaking at 30°C and 150 rpm for 30 hours to obtain an activated microbial culture.

[0043] Example 5 A method for preparing a functional organic fertilizer includes the following steps: Agricultural solid waste substrate is mixed according to the following mass percentages: 60% tomato peel and pomace, 25% crushed cotton stalks, and 15% cow and sheep manure. The initial C / N ratio is adjusted to 28:1, and the moisture content is 60%. During the initial stage of composting, 2% of the activated microbial inoculum prepared in Example 4 is inoculated into the compost pile, and aerobic fermentation is carried out. When the temperature of the compost pile naturally cools to below 45°C, 3% of the activated microbial inoculum is sprayed in, and the oxygen volume concentration inside the compost pile is adjusted to stabilize at 5.0%. Fermentation continues for 18 days to obtain the functional organic fertilizer.

[0044] Example 6: Orthogonal experimental screening and functional verification of microbial targeted activator formulations 1. Orthogonal experimental design and determination of optimal formulation The four factors with the greatest impact on the activation effect were investigated: Factor A (mass ratio of trehalose to betaine), Factor B (mass ratio of spermidine to salicylic acid), Factor C (mass ratio of potassium humate to sodium lignosulfonate), and Factor D (total amount of carbon source matrix added, i.e., the percentage of the sum of potassium humate and sodium lignosulfonate to the total mass of the activator). Each factor had three levels, using an L9 (3... 4 An orthogonal array was used. Each formulation was replenished with deionized water to bring the balance to 100%, and trace elements (0.5% ferrous sulfate and 0.2% zinc sulfate) were added at fixed levels. Factor levels are shown in Table 1.

[0045] Table 1. Orthogonal experimental factor level table for activator formulation optimization

[0046] Nine groups of activators were prepared according to the orthogonal array. Commercially available EM bacterial agent and the activator were mixed at a mass ratio of 1:8, and inoculated into slightly saline water containing 3.0% NaCl at a solid-liquid ratio of 1:20. Activation was carried out at 30℃ and 150 rpm for 30 hours. The survival rate and extracellular polymeric substance (EPS) yield were determined under a high-salt environment (5.0% NaCl). EPS was determined using the phenol-sulfuric acid colorimetric method. The orthogonal experimental design and results are shown in Table 2.

[0047] Table 2 L9 (3) 4 Orthogonal experimental design and results

[0048] To determine the order of influence of each factor on the activation effect and the optimal level, a direct range analysis was performed on the survival rate data in Table 2. The mean (K value, the average survival rate of all experiments at that level) and range (R value, i.e., Kmax-Kmin) of each factor at each level were calculated, and the results are shown in Table 3.

[0049] Table 3 Range Analysis of Survival Rate Indicators

[0050] Range analysis results showed that the factor with the greatest impact on activation was B (the ratio of spermidine to salicylic acid, R=16.50), indicating that the internal ratio of the inducer has an important influence on the regulation of the functional phenotype of the bacterial community; the second most important factor was A (the ratio of trehalose to betaine, R=6.86), indicating that the physical protection of the osmotic pressure protection matrix was also crucial; the effects of factors C (R=2.87) and D (R=1.53) were relatively small.

[0051] The mean K values ​​of each factor show that all factors reach their peak values ​​at level 2 (K2 values ​​are all maximum). Specifically: when factor A is at a ratio of 2:1, the glassy shell formed by trehalose and the intracellular osmotic pressure maintained by betaine reach a good balance; when factor B is at a ratio of 3:1, salicylic acid can effectively activate defense signaling pathways while avoiding cytotoxicity caused by excessive concentrations; when factor C is at a ratio of 1:1, the electrostatic shielding effect of potassium humate and the surface adsorption effect of sodium lignin sulfonate achieve good synergy; when factor D is at 50%, the carbon source matrix provides sufficient fast-acting carbon source without causing excessively high osmotic pressure.

[0052] Based on the comprehensive range analysis results, the optimal combination was derived as A2B2C2D2, namely: trehalose:betaine = 2:1, spermidine:salicylic acid = 3:1, potassium humate:sodium lignosulfonate = 1:1, and the total carbon source matrix addition is 50%. Converted to mass percentages according to this internal ratio, the composition is: trehalose 23.33%, betaine 11.67%, spermidine 1.52%, salicylic acid 0.48%, potassium humate 25.0%, and sodium lignosulfonate 25.0%, which is the formulation of Example 1.

[0053] 2. Validation of the effect of the boundary range of mass percentage of each component After determining the optimal internal ratio, boundary verification experiments were set up to verify the scientific validity of the mass percentage ranges described in Examples 1-3. Based on the preferred internal ratio (trehalose:betaine = 2:1, spermidine:salicylic acid = 3:1, potassium humate:sodium lignosulfonate = 1:1, trace elements fixed at 0.7%), four verification groups were configured: Comparative Example 1 (deficiency inducer), Formulation A (lower boundary), Formulation B (preferred in this invention), and Formulation C (upper boundary). The allocation of each group is shown in Table 4.

[0054] Table 4. Boundary gradient validation group for the mass percentage of a single activator ingredient (%)

[0055] Equal amounts of commercially available EM bacterial culture were inoculated into the above activation system containing 3.0% NaCl and cultured at 30℃ and 150 rpm for 30 hours. The survival rate under high salt (5.0% NaCl), cellulase activity (DNS colorimetric method) and EPS yield were measured. The results are shown in Table 5.

[0056] Table 5. Verification results of stress resistance and latex production function under different mass percentage boundary conditions.

[0057] Comparing Comparative Example 1 and Formulation B, it can be seen that although the increase in survival rate was relatively slow after adding only 2.0% spermidine / salicylic acid inducer, cellulase activity increased nearly 3 times and EPS yield increased 6 times (reaching 42.3 g / L), indicating that a specific concentration of induction signal of 1.5%-3.0% can promote the expression of genes related to extracellular polysaccharide synthesis (such as epsA) in the bacterial community. Formulations A, B, and C all achieved excellent activation effects (EPS all exceeded 20 g / L), proving that the broad protection range of 30%-40% protective matrix, 1.5%-3.0% inducer, and 40%-55% carbon source matrix of this invention is feasible. Formulation B achieved the best performance in all indicators. When the concentration continued to increase to that of Formulation C, the indicators showed a slight decline, proving that the optimal combination is the better critical point.

[0058] 3. Verification of the intergenerational stability and reproducibility of the activated phenotype The bacterial culture obtained after 30 hours of activation in Example 1 was used as the first-generation activation solution (denoted as F0). 10% (v / v) of the F0 bacterial culture was transferred to a standard basal liquid culture medium containing only 3.0% NaCl and free of any activating agent of this invention. The medium was cultured for 30 hours under the same conditions (30°C, 150 rpm) to obtain the second-generation bacterial culture (denoted as F1). F1 was cultured in the same manner to obtain the third-generation bacterial culture (denoted as F2). Simultaneously, a raw, commercially available EM bacterial culture without any activation was set up as a blank control (CK). The survival rate and EPS yield of the F0, F1, F2, and CK groups under 3.0% NaCl were measured, and the results are shown in Table 6.

[0059] Table 6 Results of intergenerational stability testing of activated phenotypes

[0060] The above results indicate that with passage through generations in an inducer-free environment, the stress resistance and gum production capacity of the F1 and F2 generations gradually decreased (F0>F1>F2). Crucially, even in the third generation (F2), its survival rate (62.8%) and EPS yield (24.26 g / L) were still more than 10 times that of the original inactivated bacteria (CK group). This demonstrates that the high stress resistance and high gum production phenotype induced by specific signaling molecules in this invention possesses a certain ability to be maintained across generations, sufficient to meet the technical requirements for industrial propagation, transportation, and initial colonization after application to saline-alkali land.

[0061] 4. Molecular biological (RT-qPCR) verification of the promotion of epsA gene expression by specific inducers. To provide molecular evidence that the spermidine / salicylic acid complex inducer can promote the expression of genes related to EPS synthesis, real-time quantitative PCR (RT-qPCR) was performed.

[0062] Total RNA was extracted from the following three groups of treated culture systems and synthesized into cDNA via reverse transcription. Using 16S rRNA as an internal reference gene, the relative expression level of epsA (representing the EPS synthesis-related gene) was detected using specific primers, and calculated using the 2-ΔΔCt method. Control group (CK): Unactivated commercially available EM bacterial culture (bacterial cells were directly obtained by centrifugation).

[0063] Comparative Example 1 (Inducer-deficient group): The 3.0% NaCl brackish water activation group was activated with an equal amount of osmotic pressure protection matrix and carbon source, but without the addition of spermidine / salicylic acid inducer.

[0064] Formula B (preferred group of the present invention): 3.0% NaCl brackish water activation group with added complete activator (containing 2.0% inducer). The results are shown in Table 7.

[0065] Table 7. Changes in relative expression levels of the core functional gene (epsA) under different treatments.

[0066] Comparing the CK group with Comparative Example 1, it can be seen that relying solely on 3.0% high salt stress and osmotic pressure substrate, the bacteria can only produce a weak stress response, with the expression level of the epsA gene increasing by 2.45 times, which is insufficient to produce a large amount of gel (corresponding to the EPS yield of Comparative Example 1 in Table 5, which was only 6.85 g / L). However, after adding a specific ratio of spermidine and salicylic acid (Formula B group), the transcription level of the epsA gene was significantly upregulated, with the relative expression level reaching 18.56 times that of the unactivated control group and 7.58 times that of Comparative Example 1. This result provides molecular-level evidence that the inducer of this invention can promote the expression of genes related to EPS synthesis.

[0067] Example 7: Parameter Optimization of the Preparation Process of Activated Microbial Incubators This embodiment verifies the activation process parameters described in Example 4. Five factors were selected: the mass ratio of bacterial agent to activator (Factor A, 1:5, 1:8, 1:10), the NaCl concentration in the slightly saline water (Factor B, 2.0%, 3.0%, 4.0%), the activation temperature (Factor C, 25℃, 30℃, 35℃), the shaking speed (Factor D, 120, 150, 180 rpm), and the activation time (Factor E, 24, 30, 36 h). Each factor had three levels, and the L18 (3 5 An orthogonal array was used. Using the activator from Example 1 as a fixed formulation, experiments were conducted according to the designed combinations to determine the survival rate and EPS yield under extreme salt stress (5.0% NaCl). Factor levels are shown in Table 8, and the experimental scheme and results are shown in Table 9.

[0068] Table 8. Orthogonal experimental factor level table for optimization of activation process parameters

[0069] Table 9 L18 (3) 5 Orthogonal experimental design and test results

[0070] To clarify the influence weight of each process parameter on activation efficiency, a direct range analysis was performed on the survival rate (Y1) in Table 9 (K value is the mean survival rate at each level of the factor, and R value is the range). The results are shown in Table 10.

[0071] Table 10 Process Range Analysis of Survival Rate Indicators

[0072] According to the range analysis results, the NaCl stress concentration (B, R=12.17) and the substrate addition ratio (A, R=10.43) are the two key parameters affecting the activation effect. When NaCl is maintained at 3.0% (B2), a moderate stress-triggered defense mechanism can be formed; when the mass ratio is 1:8 (A2), the osmotic pressure protection and induction signal concentration provided by the activator can match the transmembrane absorption requirements of cells under 3.0% salt pressure; at the same time, 30℃ (C2) provides suitable conditions for enzyme remodeling, 150rpm (D2) achieves a balance between micro-oxygen supply and protection of newly formed polysaccharides, and 30 hours (E2) is conducive to the shift of metabolic flux towards EPS synthesis.

[0073] The theoretically optimal combination derived through range analysis is A2B2C2D2E2 (i.e., mass ratio 1:8, NaCl concentration 3.0%, temperature 30℃, rotation speed 150rpm, and time 30h). To confirm this derivation, three sets of parallel supplementary verification experiments were conducted according to this optimal combination. The results showed that the survival rate under extreme salt pressure conditions under this optimized combination was as high as 88.6%, and the EPS yield was as high as 42.3g / L.

[0074] Example 8: Verification of the reverse composting process for functional organic fertilizer 1. Composting process design Using tomato peels and pomace (60%), crushed cotton stalks (25%), and cow manure (15%) as the substrate, the initial C / N ratio was adjusted to 28:1, and the moisture content was 60%. To verify the technical effect of inoculation during the cooling period and microaerobic fermentation to break the normal alkaline composting environment, three composting experiments were set up (fermentation cycle 45 days).

[0075] 2. The methods for measuring relevant indicators during the experiment are as follows: (1) pH value: The solid-liquid extraction method was used for determination. Deionized water was added to compost samples at a solid-liquid ratio of 1:10 (W / V) and soil samples at a solid-liquid ratio of 1:5 (W / V). After shaking extraction, the supernatant was measured using a precision pH meter.

[0076] (2) Seed germination index (GI) determination: Take the compost solid phase sample and deionized water at a ratio of 1:10 (W / V) for extraction, and take the supernatant to cultivate Chinese cabbage in petri dishes. Brassica campestris L Seeds. The calculation formula is: GI (%) = (germination rate of treatment group × average root length of treatment group) / (germination rate of deionized water control group × average root length of control group) × 100%.

[0077] (3) Total nitrogen (TN): The Kjeldahl method was used for determination. The sample was digested at high temperature with concentrated sulfuric acid-catalyst (K2SO4-CuSO4), and then distilled, absorbed and titrated with standard acid.

[0078] (4) Total phosphorus (TP): determined by H2SO4-H2O2 combined digestion-molybdenum antimony colorimetric method.

[0079] (5) Total potassium (TK): After the sodium hydroxide fusion method, it is determined by a flame photometer.

[0080] (6) Ammonia nitrogen (NH4) + -N) and nitrate nitrogen (NO3) - -N): Extracted with 2 mol / L KCl solution. Ammonia nitrogen was determined by indophenol blue colorimetry or flow injection analysis; nitrate nitrogen was determined by ultraviolet spectrophotometry or flow injection analysis. Available phosphorus (AP): Extracted with 0.5 mol / L NaHCO3 solution (pH 8.5), filtered, and determined by molybdenum-antimony spectrophotometry.

[0081] (7) Available potassium (AK): Extracted with 1 mol / L ammonium acetate (NH4OAc) solution (pH 7.0), filtered and measured with a flame photometer.

[0082] (8) Humic components (HS, HA, FA) and Humulus-Fulvic ratio (HA / FA): Total humic substances (HS) were extracted by leaching with a mixture of sodium pyrophosphate and sodium hydroxide (Na4P2O7-NaOH). The extract was acidified to pH 1.0-1.5, and the precipitate formed was humic acid (HA). The fulvic acid (FA) retained in the supernatant after centrifugation was fumic acid. The carbon content of each component was determined by the potassium dichromate oxidation-volume method and converted into the content of HA and FA. The ratio of the two is the Humulus-Fulvic ratio.

[0083] (9) Extracellular polymeric substances (EPS) yield: The bound EPS in the fermentation broth or compost broth was extracted by ultrasonic-centrifugation or freeze centrifugation. After purification by alcohol precipitation, the polysaccharide content was determined by a modified phenol-sulfuric acid colorimetric method (calculated using a standard curve prepared with glucose as the standard).

[0084] (10) Total organic acids: The total amount was determined by titration with NaOH standard solution (rapid determination of total amount) or by high performance liquid chromatography (HPLC, for accurate determination of specific short-chain fatty acids such as lactic acid and acetic acid). Take the extract, add phenolphthalein indicator, and titrate with standardized NaOH solution until a faint red color appears, then calculate the total amount.

[0085] (11) Greenhouse gases (CO2, CH4, N2O) and odorous gases (NH3, H2S): The closed static chamber method was used. A closed gas collection chamber was installed on top of the composting device, and the concentrations of CO2, CH4, and N2O were periodically measured using gas chromatography (GC); NH3 was measured using boric acid absorption titration; and H2S was measured using zinc acetate absorption-methylene blue spectrophotometry or a dedicated sensor. The cumulative emissions of each gas were finally calculated by integration.

[0086] Table 11 Experimental Design Table

[0087] 3. Experimental Results and Analysis according to Figure 1 The results showed that during the heating phase, activation treatment improved the degradation efficiency of the high-lignin matrix. The CK group (unactivated) only slowly heated to 55.2℃ on the 5th day, exhibiting a delayed temperature rise. In contrast, the T2 group of this invention, benefiting from the higher cellulase activity after activation in Example 4, reached 51.3℃ on the 2nd day after being placed in the pile. This indicates that activated EM bacterial solution can promote the degradation of cotton stalk fibers and release heat. The CK group maintained a temperature above 55℃ for only 4 days (peak temperature 56.9℃), while the T2 group maintained a temperature above 55℃ for 13 days, with a maximum temperature reaching 67.1℃. This not only facilitates the killing of pathogens and weed seeds but also promotes the dissociation of the dense "lignin-hemicellulose" network in the cotton stalks, providing precursors for the subsequent synthesis of targeted products. The T2 group naturally cooled to between 46.1-44.0℃ on the 18th day, coinciding with the technical window for the resuscitation of mesophilic bacteria. The temperature stabilized between 23-40℃ in the later stages (days 20-45), indicating that activated lactic acid bacteria and other microbial communities initiated the second stage of fermentation metabolism in a microaerobic environment.

[0088] according to Figure 2 The dynamic evolution of the seed germination index (GI) reveals that, in terms of decomposition and detoxification: compared to the CK group (GI of only 56.4% on day 15), the T2 group of this invention, benefiting from the efficient enzymatic hydrolysis of the initially activated microbial community, rapidly reduced the impact of inhibitory toxins such as polyphenols, with the GI rising to 92.3% on day 15 (exceeding the 80% maturity standard), shortening the traditional 30-40 day maturity period to approximately 15 days. Regarding growth promotion: by the endpoint of day 45, the CK group (78.2%) and T1 group (88.0%) only reached conventional maturity, while the T2 group's GI reached 105.0%. This result indicates that, under the synergistic metabolism of microaerobic microorganisms, activated microbial communities can increase the accumulation of extracellular polymeric substances (EPS), indoleacetic acid (IAA), and highly active fulvic acid precursors. This demonstrates that the preparation method of this invention overcomes the limitations of traditional composting methods that only treat harmlessness, and can transform it into a functional fertilizer with both growth-promoting and saline-alkali buffering effects.

[0089] according to Figure 3The results showed that during the early fermentation stage (0-15 days), the pH of all three compost groups increased from an initial 6.5 to nearly 8.0 due to high-temperature ammoniation, confirming the rapid temperature rise and degradation capabilities of the activated microbial community in the early stages. However, after day 15, the curves diverged among the groups. The pH of the conventional CK and T1 groups eventually stagnated at a slightly alkaline level (approximately 8.1); while the pH of the T2 group of this invention, after undergoing secondary inoculation during the cooling period and microaerobic intervention, gradually decreased and stabilized at 5.80 at the fermentation endpoint (day 45). This result indicates that highly active facultative anaerobic bacteria synthesize organic acids under microaerobic conditions and neutralize some free ammonia. This demonstrates that the preparation method of this invention relies on biological regulation, improving the technical problem that aerobic compost products are usually slightly alkaline, and successfully preparing an acidic functional organic fertilizer suitable for saline-alkali land improvement.

[0090] Figure 4 Cumulative emissions monitoring data show that, compared to the CK group (without activation and conventional treatment), the T2 group (activated secondary inoculation micro-aerobic process) of this invention achieved emission reductions of multiple gases. Regarding odor control and nitrogen and sulfur conservation, emissions of NH3, the core odor and nitrogen loss source, decreased by 60.3% (from 4.61 to 1.83), and H2S emissions decreased by 40.1%. These results indicate that the slightly acidic environment formed by the later-stage directed acid production in the T2 group neutralizes and fixes volatile alkaline ammonia into more stable ammonium salts, thereby reducing NH3 volatilization and improving the total nitrogen fertilizer efficiency of the products. Simultaneously, in terms of greenhouse gas suppression and in-situ carbon sequestration, CH4 and N2O emissions decreased by 44.3% and 42.1%, respectively, and CO2 emissions decreased by 24.4%. This emission reduction effect demonstrates that after T2 group was introduced into a microaerobic environment, the conversion direction of some carbon sources in the activated bacterial community was adjusted, reducing the loss of carbon sources through excessive oxidation into gaseous CO2 and CH4, and promoting their conversion into large extracellular polymeric substances (EPS colloids) locked in the solid medium. The above data indicate that this invention, through a reverse microaerobic acid production pathway, can improve the problems of significant carbon and nitrogen nutrient loss and heavy secondary gaseous pollution in traditional composting, achieving green and low-carbon production and nutrient retention.

[0091] As shown in Table 12, in terms of nutrient retention, the total nitrogen (TN) in group T2 reached 24.15 g / kg, an increase of 25.9% compared to the conventional CK group. This confirms that the slightly acidic environment formed during the micro-aerobic acid production stage successfully intercepted and neutralized volatile ammonia (echoing the earlier statement about a significant 60.3% reduction in NH3 emissions). Simultaneously, the ammonia nitrogen in the products of group T2 decreased, while the nitrate nitrogen (NO3--N) readily absorbed by crops increased to nearly three times that of group CK (1850.65 mg / kg), reducing the risk of ammonia toxicity and seedling burn after application. Regarding the activation of macronutrients, the available phosphorus (AP) and readily available potassium (AK) in group T2 increased by 48.3% and 48.0% respectively compared to group CK. This result indicates that the bio-derived organic acids, reaching 135.4 g / kg in the later stages, played a dissolving and chelating role, converting some of the slow-release phosphorus and potassium in the matrix into readily available ionic forms, thus improving fertilizer effectiveness.

[0092] Table 12 shows the effect on the nutrient content of compost products.

[0093] To ultimately evaluate the potential of organic fertilizer for saline-alkali land remediation, the targeted functional characteristics of the fermentation endpoint products were measured. According to the results in Table 13, the preparation method of this invention (Group T2) achieved deep humification while simultaneously increasing the accumulation of stress-resistant functional substances. Regarding deep humification, the total humus content of Group T2 reached 218.19 g / kg, a 60.2% increase compared to the control group (CK), and the humic acid / fatty acid ratio (HA / FA), representing product stability, significantly increased to 1.70. This confirms that the microaerobic environment facilitated the activation of microbial communities to polymerize small-molecule precursors into highly stable humic acid, enhancing the product's long-lasting fertilizer retention efficacy. More importantly, the total organic acid content in the Group T2 product increased to 135.4 g / kg, and the EPS (extracellular polymeric acid) content reached 85.6 g / kg, both exceeding 10 times that of the conventional control group (CK). This result demonstrates that the secondary inoculation during the cooling period combined with the microaerobic process of this invention can reshape the composting metabolic endpoint, promoting the directional conversion of organic matter into short-chain fatty acids and extracellular polysaccharides by microbial communities. In summary, this invention breaks through the technical limitations of traditional composting, which is mainly limited to harmless treatment. It successfully prepares a targeted functional fertilizer that combines the three effects of chemical alkali reduction with organic acid, physical sodium excretion through EPS complexation, and biological fertilizer retention with high humic acid. This provides a biological matrix with high practical value and creativity for the restoration of saline-alkali land.

[0094] Table 13 Effects on compost products

[0095] Example 9: Application Effect of Functional Organic Fertilizer in Severely Saline-Alkali Land This embodiment aims to verify the in-situ remediation efficacy of the functional organic fertilizer prepared in Example 5 in saline-alkali cotton fields in Xinjiang through a real field demonstration application, and to explore the application threshold that balances targeted improvement effect with optimal economic benefits.

[0096] 1. Overview and Design of the Experimental Site Experimental site: A severely saline-alkali cotton field in the Tarim Basin of Xinjiang (Initial soil parameters: pH 9.15, total salt content 1.25%, bulk density 1.55 g / cm³). 3 The surface has severe salt crusting, making it a typical saline-alkali land that is difficult to utilize.

[0097] Test crop: Cotton (Xinluzhong series).

[0098] The experiment consisted of four treatments, with a plot area of ​​50m². 2 The randomized block arrangement is repeated 3 times.

[0099] 2. The relevant measurement methods are as follows: (1) Percentage of aggregates >0.25mm: The conventional wet sieving method was used. Naturally air-dried undisturbed soil samples were placed on a sieve and oscillated up and down at a constant frequency in deionized water. The samples were collected, dried, and weighed. The mass of water-stable large aggregates on the sieve with a aperture >0.25mm was measured.

[0100] (2) Soil bulk density: The soil was taken in its original state using the ring cutter method. The soil was taken in its original state in the field using a standard ring cutter of known volume, weighed fresh, and then dried at 105℃ to constant weight. The mass of dry soil per unit volume was calculated.

[0101] (3) Emergence rate: The number of healthy seedlings that have fully emerged from the soil and unfolded their cotyledons in each plot was counted and divided by the total number of seeds sown in that plot to calculate the percentage.

[0102] (4) Root dry weight: Destructive sampling, dig up the entire root system of the crop, wash off the soil, first blanch at 105℃ for 30 minutes, then dry at 75℃ to constant weight, and weigh using a 0.01% analytical balance.

[0103] (5) Seed cotton yield: After the cotton bolls open and mature, standardized actual yield measurement is carried out in each plot, the total weight of seed cotton is weighed and converted into yield per mu (kg / mu).

[0104] All treatment groups were given the same amount of basic fertilizer according to local standards. The specific grouping scheme is shown in Table 14.

[0105] Table 14 Experimental Design Table

[0106] 3. Targeted improvement effect of soil physicochemical properties After a 120-day field growing season, multiple mixed samples were taken from the 0-20cm topsoil layer of each plot for analysis. The evolution of core physicochemical indicators is shown in the table. Figure 5 .

[0107] according to Figure 5 The results showed that the control group (CK) had a pH as high as 9.10 and a total salt content of 1.18%, which is higher than the suitable growth range for most crops. With the application of the functional organic fertilizer of this invention, the soil chemical environment was significantly improved. Especially at the D2 group (300 kg / mu) dosage, the rhizosphere pH dropped to 8.05, and the total salt content decreased significantly to 0.55%. This indicates that the bio-derived organic acids (lactic acid, acetic acid, etc.) abundant in the organic fertilizer can neutralize some of the soil alkalinity (OH-), while the slightly acidic environment promotes the dissolution of insoluble calcium salts, replacing harmful sodium ions (Na+) on the soil colloids, which are then leached away by irrigation water. Figure 5 b).

[0108] For the test site 1.52 g / cm 3 In the case of severe soil compaction, functional organic fertilizer showed a good physical remediation effect. Under the D2 treatment, the proportion of water-stable macroaggregates >0.25mm in the soil increased from 12.5% ​​in the CK group to 42.8% (2.4 times). Figure 5 c) Soil bulk density decreased significantly to 1.24 g / cm³ 3 ( Figure 5 d). This is mainly attributed to the application of high concentrations of EPS (extracellular polymeric substances) macromolecules. EPS can form an organic-inorganic cementing effect with soil mineral particles, improving the soil pore structure and thus reducing the risk of deep salts returning to the surface via capillary water.

[0109] This experiment also revealed the diminishing marginal effect of fertilizer dosage. Comparing group D2 (300 kg / mu) and group D3 (450 kg / mu), although group D3 had an additional 50% increase in fertilizer input, its rhizosphere pH only decreased slightly by 0.1, total salt content only decreased by 0.03%, and the proportion of aggregates only increased by 2.7%. This indicates that 300 kg / mu (group D2) is sufficient to trigger the optimal critical threshold for soil physicochemical improvement in this region. Beyond this dosage, the soil's physicochemical buffer system tends to saturate, and further increases in fertilizer application are unlikely to yield proportional ecological benefits; instead, they will increase agricultural production costs.

[0110] 4. Cotton growth and yield response according to Figure 6 The results showed that, in response to the problem of poor seedling emergence caused by salt crusting in severely saline-alkali land in Xinjiang, the cotton emergence rate increased from 48.5% in the control group (CK) to 94.5% after applying the preferred dosage of this invention (D2 group, 300 kg / mu). Figure 6a) Basic full seedling emergence was achieved. This indicates that the high content of EPS colloid (85.6 g / kg) in the fertilizer can loosen the soil physical structure and, in conjunction with bio-derived organic acids, lower the rhizosphere pH, alleviating the dual stress of physical compaction and strong alkali toxicity, thus ensuring seedling emergence and survival. Simultaneously, the construction of a suitable acid-base buffer system and nutrient pool in the rhizosphere microdomain promoted deep root development and lateral growth, resulting in the root dry weight of group D2 reaching 2.76 times that of group CK (5.8 g / plant). Figure 6 (b) This lays the foundation for increased yield in the later stages. The final seed cotton yield data further illustrates the nonlinear yield-increasing effect and optimal economic threshold of this invention: the yield of group D2 reached 438.5 kg / mu ( Figure 6 c), achieving a 94.5% increase compared to the CK group ( Figure 6 d).

[0111] More importantly, when the fertilizer application rate was further increased to 450 kg / mu (D3 group), although the input increased by 50%, the germination rate only increased slightly by 0.7%, and the yield only increased by 1.5% (6.7 kg / mu). This diminishing marginal effect indicates that 300 kg / mu is the critical technical threshold for triggering the optimal improvement effect of this invention. The definition of this dosage not only proves that the soil improvement potential tends to saturate after exceeding this threshold, but also reflects that the parameter setting of this invention takes into account both ecological targeted restoration capabilities and agricultural economic benefits.

[0112] 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 microbial targeted activator, characterized in that, The total mass of the microbial targeted activator comprises the following components: Trehalose 18.0%-28.6%, betaine 8.5%-16.0%, spermidine 1.0%-2.6%, salicylic acid 0.2%-1.0%, potassium humate 13.3%-36.7%, sodium lignosulfonate 13.3%-36.7%, ferrous sulfate 0.2%-0.8%, zinc sulfate 0.1%-0.5%, with the balance being water, and the sum of the above components and water is 100%.

2. The microbial targeted activator according to claim 1, characterized in that, The mass ratio of trehalose to betaine is (1.5-2.5):1; the mass ratio of spermidine to salicylic acid is (2-5):1; and the mass ratio of potassium humate to sodium lignosulfonate is (1-2):(1-2).

3. A method for preparing activated microbial bacterial solution, characterized in that, Includes the following steps: Mix the EM bacterial agent with the microbial directional activator according to claim 1 or 2 at a mass ratio of 1:(8-10), and inoculate it into slightly saline water to construct an activation system; activate the activation system by shaking at 28-35℃ and 120-180rpm for 24-36 hours to obtain an activated microbial bacterial solution.

4. The preparation method according to claim 3, characterized in that, The slightly saline water contains 2.0%-4.0% NaCl.

5. A method for preparing a functional organic fertilizer, characterized in that, Includes the following steps: After the agricultural solid waste substrate is mixed, the initial C / N ratio and moisture content are adjusted. In the early stage of pile construction, the activated microbial liquid prepared by the preparation method described in claim 3 or 4 is inoculated at 2-3% of the pile mass for aerobic fermentation. Once the temperature of the pile has naturally cooled to below 45°C, spray 3-5% of the activated microbial solution to stabilize the oxygen volume concentration inside the pile at 3.0%-8.0%, and continue fermentation for 15-20 days to obtain functional organic fertilizer.

6. The preparation method according to claim 5, characterized in that, The oxygen volume concentration inside the pile is adjusted by reducing the frequency of turning the pile or controlling the ventilation volume.

7. The preparation method according to claim 5, characterized in that, Agricultural solid waste substrates, by mass percentage, include: fruit pomace 55%-65%, crushed cotton stalks 20%-30%, and livestock and poultry manure 10%-20%.

8. The preparation method according to claim 5, characterized in that, The pomace is tomato peel residue.

9. The functional organic fertilizer prepared by the preparation method according to any one of claims 5-8.

10. The application of the functional organic fertilizer according to claim 9 in the preparation of saline-alkali soil conditioner.

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