Bioactive drip irrigation fertilizer for Xinjiang saline-alkali soil as well as preparation method and application thereof

Abstract

The invention relates to a bioactive drip irrigation fertilizer for Xinjiang saline-alkali soil and a preparation method and application thereof, and belongs to the technical field of agricultural fertilizers and soil improvement. The bioactive drip irrigation fertilizer prepared by compounding the red carbon quantum dot-yellow potassium composite mother liquor and the endophytic mycorrhizal fungus inoculant is particularly suitable for cotton planting in saline-alkali soil in Xinjiang, the oil content of cotton seeds can be remarkably increased, the content of harmful ingredients can be reduced, the food safety, oxidation stability and nutritional value of refined cotton seed oil can be improved, and the drip irrigation fertilizer can be applied to cotton planting in saline-alkali soil in Xinjiang. The method is of great significance in improving crop quality and terminal agricultural product quality.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizer and soil improvement technology, specifically to a bioactive drip irrigation fertilizer for saline-alkali land in Xinjiang, its preparation method, and its application. Background Technology

[0002] Xinjiang is an important cotton-producing area in my country, but local agriculture has long faced the severe challenge of soil salinization. Excessive sodium ion content in saline-alkali land leads to severe soil compaction, deterioration of aeration and permeability, hindered crop root development, and low efficiency in water and nutrient absorption. This not only reduces cotton yield but also directly affects cotton seed quality and planting efficiency.

[0003] In existing technologies, saline-alkali land improvement typically relies on single or limited technological approaches. Chemical amendments, such as potassium humate, can alleviate salt damage by chelating sodium ions and improving soil structure, but their effects are mainly concentrated on improving the rhizosphere chemical environment, with limited impact on enhancing crop photosynthetic capacity and physiological resistance. Biological amendments, such as arbuscular mycorrhizal fungi (AMF), can enhance nutrient absorption through symbiotic systems, but their colonization efficiency and functional stability are often insufficient under high saline-alkali stress, and they lack a direct effect on improving aboveground photosynthetic performance. Furthermore, Chinese patent CN121022386A reports a dual-emission carbon dot nanozyme prepared from glutathione and formamide, which can enhance crop photosynthetic efficiency and salt stress resistance; however, the novel nanomaterial itself does not possess the ability to improve soil physicochemical properties or construct beneficial rhizosphere microbial communities.

[0004] The production obstacles of crops in saline-alkali land are the result of multiple stresses intertwined among soil, microorganisms, and plants. No single method or simple combination can effectively improve the overall function of crops under adversity. Currently, there is a lack of a solution that can systematically integrate and synergistically design the three key links of "soil chemical improvement," "root biological symbiosis," and "above-ground photophysiological regulation." More importantly, existing technologies mostly focus on improving basic agronomic traits such as crop survival rate and biomass, while neglecting key indicators of economic output quality under saline-alkali land conditions—such as oil content, oil safety, and nutritional quality of cotton and cottonseed—and failing to provide effective and stable ways to improve them. This has become a significant technical bottleneck restricting the realization of the value of agricultural products in saline-alkali land.

[0005] Therefore, in response to the problems of poor soil structure, severe salt damage, low water and fertilizer utilization efficiency, and difficulty in ensuring cotton seed quality in Xinjiang saline-alkali land cotton planting, there is an urgent need to develop a new type of compound fertilizer product that can synergistically enhance efficiency, is suitable for drip irrigation systems, and can fundamentally improve crop yield and quality. Summary of the Invention

[0006] In view of the above-mentioned prior art, the purpose of this invention is to provide a bioactive drip irrigation fertilizer for saline-alkali land in Xinjiang, its preparation method, and its application. This invention develops a novel solution that is applicable to modern drip irrigation systems and can simultaneously improve the quality of crops in saline-alkali land.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention creatively constructs a ternary synergistic system of "light energy conversion - soil chemical improvement - root biological symbiosis". This system is not a simple superposition of components, but rather, through functional complementarity and temporal coordination, it systematically breaks through multiple bottlenecks limiting crop growth in saline-alkali land by enhancing plant photosynthetic efficiency, improving the rhizosphere soil environment, and expanding the root absorption network, thereby improving crop quality.

[0008] In a first aspect, the present invention provides a bioactive drip irrigation fertilizer for saline-alkali land in Xinjiang, wherein the bioactive drip irrigation fertilizer is prepared by mixing red carbon quantum dot-yellow potassium composite mother liquor with endomycorrhizal fungal agent at a volume ratio of (4-6):1. The red carbon quantum dot-potassium composite mother liquor is prepared by mixing red carbon quantum dot mother liquor and potassium precipitate mother liquor at a volume ratio of (0.25-0.35):1.

[0009] Preferably, the method for preparing the potassium sulfide mother liquor includes the following steps: a. Mix water, lignite, potassium hydroxide and sodium sulfite in a mass ratio of (3.0-4.0):1:(0.07-0.09):(0.07-0.09), heat to 90-100℃, and stir continuously at this temperature for 20-40 minutes to obtain the reaction mixture; b. Continue heating the reaction mixture obtained in step a to 175-195℃ and maintain the temperature for 1-2 hours; c. After the reaction is complete, the material is separated into solid and liquid components, the supernatant is collected, and citric acid is added to the supernatant to adjust the pH to 6.5-7.5 to obtain the potassium sulfide mother liquor.

[0010] The core function of the potassium chlorohydrate mother liquor is to physically improve saline-alkali soil by complexing harmful sodium ions in the soil with active functional groups and promoting the formation of aggregate structure, and to create a good root zone environment for microbial reproduction, activity and crop growth.

[0011] Preferably, the preparation method of the red carbon quantum dot mother liquor includes the following steps: a. Mix glutathione and formamide at a mass ratio of 1:(20-35) and stir to dissolve to obtain a precursor solution; b. The precursor solution is heated in a closed environment at 160-200°C for 1-3 hours, and then cooled to room temperature; c. The cooled reaction solution was purified by dialysis using a dialysis bag with a molecular weight cutoff of 2000-4000 Daltons. The solution in the bag was collected to obtain a red carbon quantum dot mother liquor.

[0012] The red carbon quantum dot mother liquor exhibits characteristic emission peaks at 650 nm and 680 nm under 360 nm excitation light.

[0013] The red carbon quantum dot mother liquor can directly improve the photosynthetic efficiency of leaves, especially the lower and middle leaves of the canopy; at the same time, its nanoscale characteristics enable it to act as a mild stress signal to activate the plant's antioxidant system and enhance the crop's stress resistance from a physiological perspective.

[0014] Preferably, the bioactive drip irrigation fertilizer is mixed with irrigation water to prepare a drip irrigation fertilizer solution, which is then dripped onto the crop root zone; wherein the volume concentration of the bioactive drip irrigation fertilizer in the drip irrigation fertilizer solution is 0.1%-1.0%.

[0015] Drip irrigation ensures that the active ingredients can reach the crop root zone precisely and evenly, greatly improving the colonization efficiency of mycorrhizal fungi and the stability of the function of each component in saline-alkali stress environment.

[0016] In a second aspect, the present invention provides the application of the above-mentioned bioactive drip irrigation fertilizer in improving the quality of cottonseed produced in saline-alkali land.

[0017] Preferably, the improvement of cottonseed quality produced in saline-alkali land includes one or more of the following: increasing the oil content of cottonseed, reducing the gossypol content of cottonseed, increasing the kernel-to-hull ratio of cottonseed, and reducing the phospholipid content in cottonseed crude oil.

[0018] In a third aspect, the present invention provides the application of the above-mentioned bioactive drip irrigation fertilizer in improving the quality of refined cottonseed oil produced from cottonseed grown in saline-alkali land.

[0019] Preferably, the improvement of the quality of refined cottonseed oil obtained from cottonseed produced in saline-alkali land includes one or more of the following: reducing benzo[a]pyrene content, reducing aflatoxin B1 content, reducing acid value, reducing peroxide value, increasing linoleic acid ratio, and increasing natural tocopherol content.

[0020] In a fourth aspect, the present invention provides a method for preparing the above-mentioned bioactive drip irrigation fertilizer, comprising the following steps: S1. Preparation of potassium sulfite mother liquor: Water, lignite, potassium hydroxide and sodium sulfite are mixed in a mass ratio of (3.0-4.0):1:(0.07-0.09):(0.07-0.09), and reacted sequentially at 90-100℃ for 20-40 minutes and at 175-195℃ under pressure for 1-2 hours. After solid-liquid separation and pH adjustment to 6.5-7.5, potassium sulfite mother liquor is obtained. S2. Preparation of red carbon quantum dot mother liquor: Mix glutathione and formamide at a mass ratio of 1:(20-35), react at 160-200℃ for 1-3 hours, and obtain red carbon quantum dot mother liquor after dialysis purification; S3. Preparation of composite mother liquor: The red carbon quantum dot mother liquor obtained in step S2 and the yellow potassium mother liquor obtained in step S1 are mixed at a volume ratio of (0.25-0.35):1 to obtain a red carbon quantum dot-yellow potassium composite mother liquor; S4. Compound finished product: The red carbon quantum dot-yellow potassium composite mother liquor obtained in step S3 is mixed with the endomycorrhizal fungal agent at a volume ratio of (4-6):1 to obtain the bioactive drip irrigation fertilizer.

[0021] The initial preparation of the red carbon quantum dot-potassium composite mother liquor allows for the pre-combination of the chemical modifier and photophysiological regulator, facilitating their immediate synergistic effect during application. After preparation, the red carbon quantum dot-potassium composite mother liquor is further compounded with an endomycorrhizal fungal agent to ensure the bioactivity of the temperature-sensitive mycorrhizal fungi, while simultaneously guaranteeing the homogeneity and stability of the final product system.

[0022] The beneficial effects of this invention are: 1. This invention creatively combines three functionally complementary components—red carbon quantum dot mother liquor, yellow potassium mother liquor, and endomycorrhizal fungi—to prepare a bioactive drip irrigation fertilizer particularly suitable for cotton cultivation in saline-alkali soils of Xinjiang. Applying this bioactive drip irrigation fertilizer to cotton significantly improves the quality of cottonseed from saline-alkali soils. This improvement in cottonseed quality directly translates to its processed products, enhancing the quality and safety of the final edible vegetable oil from the source.

[0023] 2. This invention's product is designed as a stable liquid formulation, specifically for the drip irrigation system widely used in Xinjiang. This formulation and application method ensure that the active ingredients (especially temperature-sensitive endomycorrhizal fungal spores) are accurately, evenly, and directly delivered to the crop root zone. This significantly improves the colonization success rate of functional microorganisms in harsh saline-alkali environments and the stable performance of each component, solving the problem of unstable efficacy of biological agents in saline-alkali land applications, and aligning with the direction of green agriculture and sustainable development. Attached Figure Description

[0024] Figure 1 shows a transmission electron microscope (TEM) image and particle size distribution curve of the red carbon quantum dots described in this invention; the inset is a high-resolution transmission electron microscope (HRTEM) image showing the lattice fringes of the carbon quantum dots (lattice spacing of 0.21 nm).

[0025] Figure 2 shows the steady-state fluorescence spectrum of the red carbon quantum dot mother liquor described in this invention; wherein Figure 2 Image A shows the excitation spectrum of the red carbon quantum dot mother liquor. Figure 2 Image B shows the emission spectrum of the red carbon quantum dot mother liquor.

[0026] Figure 3 shows a fluorescence luminescence image of the red carbon quantum dot mother liquor used in this invention under 360 nm ultraviolet excitation light; the image shows that the carbon quantum dot mother liquor exhibits bright red fluorescence. Detailed Implementation

[0027] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0028] This invention provides a systematic solution for crop growth in saline-alkali land by constructing a ternary synergistic system of "light energy conversion - soil chemical improvement - root biological symbiosis". This solution is not a simple superposition of single technologies, but achieves simultaneous optimization of the aboveground physiology of crops, rhizosphere environment and soil matrix through functional complementarity and spatiotemporal coupling, thereby producing a synergistic effect that is significantly better than the individual use or simple combination of each component.

[0029] Specifically, the bioactive drip irrigation fertilizer of this invention can significantly enhance the photosynthesis and stress resistance of crops in saline-alkali land. Red carbon quantum dots, as a highly efficient light energy conversion material, convert ultraviolet light that crops cannot fully utilize into usable red light, directly improving the overall light energy utilization rate of the canopy, especially under weak light conditions. Simultaneously, its nano-properties can gently activate the plant's antioxidant system, helping to eliminate excess reactive oxygen species generated by saline-alkali stress and protecting cell structure and function. The potassium sulfide mother liquor can rapidly chelate harmful sodium ions in the soil, reducing rhizosphere salt concentration and osmotic stress, and improving soil physical properties by promoting aggregate formation, creating a favorable environment for root growth and microbial activity. Endophytic mycorrhizal fungi, through their extensive hyphal network, greatly expand the root absorption range, efficiently activating and transporting poorly mobile nutrients such as phosphorus and zinc, as well as water, in the soil, directly enhancing the plant's ability to acquire nutrients and water.

[0030] The bioactive drip irrigation fertilizer prepared by the above compounding can simultaneously and significantly improve the crop quality of crops in saline-alkali land. Field trial data show that after applying this product, the oil content of cottonseed in Xinjiang saline-alkali land is significantly increased, the kernel-to-hull ratio is increased, and the content of components that are not conducive to processing and safety, such as gossypol and phospholipids, is reduced.

[0031] This invention further enhances the quality and safety of finished edible vegetable oils at the source. Refined cottonseed oil processed from treated cottonseed showed a significant reduction in the content of safety risk factors such as benzo[a]pyrene and aflatoxin B1, and a marked improvement in indicators reflecting oxidative stability, such as acid value and peroxide value. Furthermore, the fatty acid composition of the oil was more balanced (e.g., an increased proportion of linoleic acid), and the content of the natural antioxidant tocopherol increased. This demonstrates that this invention, by promoting healthy crop growth, endows agricultural products with superior nutritional value and storage stability from the source.

[0032] From an agronomic practice perspective, the product of this invention is a stable liquid formulation specifically designed for drip irrigation systems. This design ensures that the active ingredients (especially temperature-sensitive mycorrhizal fungal spores) can be accurately, evenly, and directly delivered to the crop root zone, greatly improving the colonization success rate of functional microorganisms and the efficiency of each component's function in harsh saline-alkali environments.

[0033] In summary, the bioactive drip irrigation fertilizer and its application method provided by this invention successfully combine nanomaterials, organic chemistry and microbial technology to form a set of integrated technologies for improving the quality and efficiency of saline-alkali land agriculture that are highly operable, have synergistic effects and significant benefits, and have good application prospects and promotion value.

[0034] The specific embodiments of the present invention will be described in further detail below with reference to examples. The following detailed descriptions are illustrative and intended to provide further explanation of this application, rather than limiting the scope of the invention.

[0035] In this embodiment, the lignite was purchased from Xinzhongshenglihe Company in Qingshuihe County, Hohhot, Inner Mongolia.

[0036] The commercially available Jinyuantang Diege endomycorrhizal fungicide (effective strain name: Rhizocystis jirovecii) was purchased from Jinyuantang Gengbao New Materials Xi'an Co., Ltd.

[0037] Example 1: Preparation of Bioactive Drip Irrigation Fertilizer (1) Preparation of potassium sulfide mother liquor: a. Add 350 kg of water to the reaction vessel, then add 100 kg of lignite crushed to 80 mesh, 8 kg of potassium hydroxide, and 8 kg of sodium sulfite as a catalyst. Start stirring and heating, raise the temperature of the mixture to 95°C, and continue stirring and reacting at this temperature for 30 minutes.

[0038] b. Transfer the above reaction mixture to a pressure reactor, continue heating to 185°C, and maintain the temperature for 1.5 hours to allow the lignite to fully degrade and combine with potassium.

[0039] c. After the reaction is complete, the materials are centrifuged and the supernatant is collected. Citric acid is added to the supernatant to adjust the pH to 7, thus obtaining the potassium sulfide mother liquor.

[0040] (2) Preparation of red carbon quantum dot mother liquor a. Weigh 1.75 kg of glutathione and 47.5 kg of formamide and stir and mix at room temperature until glutathione is completely dissolved in formamide to obtain a clear precursor solution.

[0041] b. Place the precursor solution in a sealed environment and heat for 2 hours at 180°C. After the reaction is complete, allow it to cool naturally to room temperature.

[0042] c. Transfer the cooled reaction solution to a dialysis apparatus with a molecular weight cutoff of 3500 Daltons, and dialyze it with water for 48 hours, changing the water every 8 hours. Collect the solution in the dialysis apparatus to obtain the red carbon quantum dot mother liquor.

[0043] Characterization revealed that the carbon quantum dots in the red carbon quantum dot mother liquor were distributed in the range of 1.0-3.5 nm in size, with an average particle size of 2.0 nm. Figure 1 The quantum efficiency is 15%, and the chemical oxygen demand (COD) is 5 × 10⁻⁶. 6 mg / L. Under 360 nm excitation light, its photoluminescence spectrum shows characteristic emission peaks at 650 nm and 680 nm. Figure 2 ).

[0044] (3) Preparation of red carbon quantum dot-yellow potassium composite mother liquor: Add the prepared red carbon quantum dot mother liquor to 30% of the total volume of the potassium chlorophyll mother liquor, and stir continuously for 1 hour to ensure thorough mixing, thus obtaining the red carbon quantum dot-potassium chlorophyll composite mother liquor.

[0045] (4) Compounding of finished drip irrigation fertilizers: The red carbon quantum dot-potassium composite mother liquor obtained in step (3) is mixed with the commercially available Jin Yuan Tang Die Ge endomycorrhizal fungus agent liquid at a volume ratio of 5:1. After thorough mixing, the bioactive drip irrigation fertilizer product of this invention is obtained. This product is a homogeneous and stable liquid, suitable for application through a drip irrigation system.

[0046] Example 2: Preparation of Bioactive Drip Irrigation Fertilizer (1) Preparation of potassium sulfide mother liquor: a. Add 315 kg of water to the reaction vessel, then add 100 kg of lignite (crushed to 80 mesh), 7.5 kg of potassium hydroxide, and 8.5 kg of sodium sulfite as a catalyst. Turn on stirring and heating, raising the mixture to 92°C, and continue stirring at this temperature for 35 minutes.

[0047] b. Transfer the above reaction mixture to a pressurized reactor, continue heating to 182°C, and maintain the temperature for 1.8 hours.

[0048] c. After the reaction is complete, the materials are centrifuged and the supernatant is collected. Citric acid is added to the supernatant to adjust the pH to 6.8, which yields the potassium sulfide mother liquor.

[0049] (2) Preparation of red carbon quantum dot mother liquor a. Weigh 4 kg of glutathione and 100 kg of formamide and stir at room temperature until the glutathione is completely dissolved to obtain a clear precursor solution.

[0050] b. Place the precursor solution in a sealed environment and heat for 2.5 hours at 170°C. After the reaction is complete, allow it to cool naturally to room temperature.

[0051] c. Transfer the cooled reaction solution to a dialysis apparatus with a molecular weight cutoff of 3500 Daltons, and purify by dialysis with water for 48 hours, changing the water every 8 hours. Collect the solution in the dialysis apparatus to obtain the red carbon quantum dot mother liquor.

[0052] (3) Preparation of red carbon quantum dot-yellow potassium composite mother liquor: Add the prepared red carbon quantum dot mother liquor to 28% of the total volume of the potassium chlorophyll mother liquor, and stir continuously for 1 hour to ensure thorough mixing, thus obtaining the red carbon quantum dot-potassium chlorophyll composite mother liquor.

[0053] (4) Compounding of finished drip irrigation fertilizers: The red carbon quantum dot-yellow potassium composite mother liquor obtained in step (3) is mixed with the commercially available Jinyuantang Diege endomycorrhizal fungus agent liquid at a volume ratio of 4.5:1. After mixing evenly, the bioactive drip irrigation fertilizer product of the present invention is obtained.

[0054] Comparative Example 1: Preparation of Drip Irrigation Fertilizer The difference between the preparation method of the drip irrigation fertilizer in Comparative Example 1 and the bioactive drip irrigation fertilizer in Example 1 is that the drip irrigation fertilizer in Comparative Example 1 does not contain mycorrhizal fungi and is composed only of red carbon quantum dot-yellow potassium composite mother liquor.

[0055] Comparative Example 2: Preparation of Drip Irrigation Fertilizer The difference between the preparation method of the drip irrigation fertilizer in Comparative Example 2 and the bioactive drip irrigation fertilizer in Example 1 is that the drip irrigation fertilizer in Comparative Example 2 does not contain potassium chlorohydrate stock solution, but is prepared by compounding red carbon quantum dot stock solution and mycorrhizal fungicide in a certain proportion. The specific preparation method is as follows: (1) Preparation of red carbon quantum dot mother liquor Same as Example 1.

[0056] (2) Compound formulation of ready-made drip irrigation fertilizer: The red carbon quantum dot mother liquor obtained in step (1) is mixed with the commercially available Jinyuantang Diege endomycorrhizal fungal agent liquid at a volume ratio of 5:1. After mixing evenly, the drip irrigation fertilizer product is obtained.

[0057] Comparative Example 3: Preparation of Drip Irrigation Fertilizer The difference between the preparation method of the drip irrigation fertilizer in Comparative Example 3 and the bioactive drip irrigation fertilizer in Example 1 is that the drip irrigation fertilizer in Comparative Example 3 does not contain red carbon quantum dot mother liquor, but is prepared by compounding yellow potassium mother liquor and mycorrhizal fungi agent in a certain proportion. The specific preparation method is as follows: (1) Preparation of potassium sulfide mother liquor: Same as Example 1 (2) Compound formulation of ready-made drip irrigation fertilizer: The potassium complex mother liquor obtained in step (1) is mixed with the commercially available Jinyuantang Diege endomycorrhizal fungal agent liquid at a volume ratio of 5:1. After mixing evenly, the drip irrigation fertilizer product is obtained.

[0058] Experimental Example: Field Application and Synergistic Effect Verification Experiment of Cotton in Saline-Alkali Land, Xinjiang (1) Overview of the test site The experiment was conducted in Longkou Village, Wolitograk Town, Jiashi County, southern Xinjiang. The test plot was a cotton field that had been affected by salinization for a long time. Before sowing, the basic properties of the topsoil layer (0-20 cm) were measured: pH 8.7, electrical conductivity (EC) 3.8 mS / cm, total salt content 3.2 g / kg, soil compaction, and low organic matter content.

[0059] (2) Experimental Design Configure the following four processes: Treatment T1 (product group of the present invention): Apply bioactive drip irrigation fertilizer prepared according to the method of Example 1.

[0060] Treatment T2 (strain-deficient group): Apply drip irrigation fertilizer prepared in Comparative Example 1.

[0061] Treatment T3 (potassium-deficient mother liquor group): applied drip irrigation fertilizer prepared in Comparative Example 2.

[0062] Treatment T4 (red carbon quantum dot-deficient mother liquor group): Apply drip irrigation fertilizer prepared in Comparative Example 3.

[0063] Treatment CK (conventional control): Apply locally available commercially available water-soluble fertilizer.

[0064] Each treatment was repeated 3 times, with completely randomized block arrangements and a plot size of 0.5 acres.

[0065] (3) Field implementation The cotton variety used in the experiment was 'Xinluzhong 82'. Mechanical sowing under plastic film was carried out on April 6, 2025. All treatments used a unified drip irrigation and fertigation system under plastic film for irrigation and management.

[0066] Fertilizer application: During the key growth stages of cotton in each treatment plot (seedling stage, bud stage, and boll-forming stage), mix the corresponding fertilizer product at a rate of 2 L per acre with irrigation water to prepare a 0.2% (volume concentration) solution for drip irrigation, and apply it with the irrigation water. A total of 3 drip applications are performed throughout the entire growth period.

[0067] Other field management (cultivation, weeding, chemical control, etc.) are carried out uniformly according to the local planting model.

[0068] (4) Observation, sampling and measurement a. Cottonseed sample collection: Cotton in each treatment plot reached maturity between October 29th and 30th, 2025. A defoliant was sprayed uniformly 7 days before harvest. After the cotton leaves fell off, a cotton harvester was used for a one-time mechanical harvest to obtain seed cotton.

[0069] The seed cotton harvested from each plot was sent to a standardized cotton ginning plant for mechanical ginning to separate lint and cottonseed. The cottonseed from each treatment was collected, mixed, and used as an analytical sample.

[0070] b. Cottonseed quality determination: Oil content: determined by Soxhlet extraction (GB 5009.6).

[0071] Gossypol content: determined by high performance liquid chromatography (GB / T 25219).

[0072] Phospholipid content: The phospholipid content in crude oil extracted from cottonseed was determined by the molybdenum blue colorimetric method in accordance with national standards.

[0073] Kernel-hull ratio: Randomly select 100 whole cottonseeds, manually peel them, weigh the kernels and hulls separately, and calculate the kernel ratio.

[0074] c. Cottonseed Oil Quality Analysis: Cottonseed samples from all treatments were entrusted to the same oil processing plant and processed using the exact same process (cleaning, hulling, conditioning, pressing, refining, degumming, deacidification, decolorization, and deodorization) to produce Grade 1 refined cottonseed oil. The finished oil was then subjected to the following tests: Safety indicators: Benzo[a]pyrene (GB 5009.27), aflatoxin B1 (GB 5009.22), and gossypol residue (GB / T5009.148).

[0075] Physicochemical properties: acid value (GB 5009.229), peroxide value (GB 5009.227).

[0076] Nutritional indicators: fatty acid composition (gas chromatography, GB 5009.168, focusing on the ratio of palmitic acid, oleic acid and linoleic acid), and natural tocopherol content (high performance liquid chromatography, GB 5009.82).

[0077] (5) Experimental Results and Analysis The statistical data on cottonseed quality are shown in Table 1, as detailed below: Table 1: Effects of different treatments on cottonseed quality Table 1 shows that, although the T2-T4 groups showed some improvement compared to the conventional control (CK), the increases in cottonseed oil content and kernel-to-hull ratio, as well as the decreases in gossypol and phospholipids, were far less significant than those in the T1 group. This demonstrates a significant synergistic effect among the red carbon quantum dot mother liquor, the yellow potassium mother liquor, and the endomycorrhizal fungi, which collectively optimized cottonseed development and nutrient accumulation.

[0078] The quality test results of refined cottonseed oil are shown in Table 2, as detailed below: Table 2: Comparison of the quality of refined cottonseed oil produced from cottonseed treated with different methods The main fatty acid composition of refined cottonseed oil in each treatment group is as follows: Group T1: The proportions of palmitic acid, oleic acid and linoleic acid were 20.32%, 21.70% and 54.08%, respectively.

[0079] Group T2: The proportions of palmitic acid, oleic acid and linoleic acid were 22.29%, 23.21% and 50.60%, respectively.

[0080] Group T3: The proportions of palmitic acid, oleic acid and linoleic acid were 22.07%, 23.24% and 50.79%, respectively.

[0081] Group T4: The proportions of palmitic acid, oleic acid and linoleic acid were 23.81%, 23.16% and 49.13%, respectively.

[0082] In the CK group, the proportions of palmitic acid, oleic acid, and linoleic acid were 23.99%, 23.46%, and 48.65%, respectively.

[0083] The above data shows that cottonseed oil treated in group T1 exhibits comprehensive and significant advantages in safety (lowest levels of benzo[a]pyrene and mycotoxins), oxidative stability (lowest acid value and peroxide value), and nutritional value (highest proportion of linoleic acid and highest content of natural tocopherols). This demonstrates that plants treated in group T1 exhibit a stronger cell membrane system and antioxidant capacity, reducing precursors of oil oxidation and toxic contamination at the source, and also influencing the fatty acid composition and the synthesis and accumulation of associated compounds in the oil. This directly verifies that the bioactive drip irrigation fertilizer provided by this invention can fundamentally improve the quality and safety of finished agricultural products.

[0084] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications made within the spirit and principles of this application are not permitted. Equivalent substitutions and improvements should all be included within the scope of protection of this application.

Claims

1. A bioactive drip irrigation fertilizer for saline-alkali land in Xinjiang, characterized in that, The bioactive drip irrigation fertilizer is prepared by mixing red carbon quantum dot-yellow potassium composite mother liquor and endomycorrhizal fungi agent at a volume ratio of (4-6):

1. The red carbon quantum dot-potassium composite mother liquor is prepared by mixing red carbon quantum dot mother liquor and potassium precipitate mother liquor at a volume ratio of (0.25-0.35):

1.

2. The bioactive drip irrigation fertilizer according to claim 1, characterized in that, The preparation method of the potassium sulfide mother liquor includes the following steps: a. Mix water, lignite, potassium hydroxide and sodium sulfite in a mass ratio of (3.0-4.0):1:(0.07-0.09):(0.07-0.09), heat to 90-100℃, and stir continuously at this temperature for 20-40 minutes to obtain the reaction mixture; b. Continue heating the reaction mixture obtained in step a to 175-195℃ and maintain the temperature for 1-2 hours; c. After the reaction is complete, the material is separated into solid and liquid components, the supernatant is collected, and citric acid is added to the supernatant to adjust the pH to 6.5-7.5 to obtain the potassium sulfide mother liquor.

3. The bioactive drip irrigation fertilizer according to claim 1, characterized in that, The preparation method of the red carbon quantum dot mother liquor includes the following steps: a. Mix glutathione and formamide at a mass ratio of 1:(20-35) and stir to dissolve to obtain a precursor solution; b. The precursor solution is heated in a closed environment at 160-200°C for 1-3 hours, and then cooled to room temperature; c. The cooled reaction solution was purified by dialysis using a dialysis bag with a molecular weight cutoff of 2000-4000 Daltons. The solution in the bag was collected to obtain a red carbon quantum dot mother liquor.

4. The bioactive drip irrigation fertilizer according to claim 3, characterized in that, The red carbon quantum dot mother liquor exhibits characteristic emission peaks at 650 nm and 680 nm under 360 nm excitation light.

5. The bioactive drip irrigation fertilizer according to any one of claims 1-4, characterized in that, The bioactive drip irrigation fertilizer is mixed with irrigation water to form a drip irrigation fertilizer solution, which is then dripped onto the crop root zone; wherein the volume concentration of the bioactive drip irrigation fertilizer in the drip irrigation fertilizer solution is 0.1%-1.0%.

6. The application of the bioactive drip irrigation fertilizer according to any one of claims 1-4 in improving the quality of cottonseed produced in saline-alkali land.

7. The application according to claim 6, characterized in that, The improvement of cottonseed quality produced in saline-alkali land includes one or more of the following: increasing the oil content of cottonseed, reducing the gossypol content of cottonseed, increasing the kernel-to-hull ratio of cottonseed, and reducing the phospholipid content in cottonseed crude oil.

8. The application of the bioactive drip irrigation fertilizer according to any one of claims 1-4 in improving the quality of refined cottonseed oil produced from cottonseed grown in saline-alkali land.

9. The application according to claim 8, characterized in that, The improvement of the quality of refined cottonseed oil produced from cottonseed grown in saline-alkali land includes one or more of the following: reducing benzo[a]pyrene content, reducing aflatoxin B1 content, reducing acid value, reducing peroxide value, increasing linoleic acid ratio, and increasing natural tocopherol content.

10. A method for preparing the bioactive drip irrigation fertilizer according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Preparation of potassium sulfite mother liquor: Water, lignite, potassium hydroxide and sodium sulfite are mixed in a mass ratio of (3.0-4.0):1:(0.07-0.09):(0.07-0.09), and reacted sequentially at 90-100℃ for 20-40 minutes and at 175-195℃ under pressure for 1-2 hours. After solid-liquid separation and pH adjustment to 6.5-7.5, potassium sulfite mother liquor is obtained. S2. Preparation of red carbon quantum dot mother liquor: Mix glutathione and formamide at a mass ratio of 1:(20-35), react at 160-200℃ for 1-3 hours, and obtain red carbon quantum dot mother liquor after dialysis purification; S3. Preparation of composite mother liquor: The red carbon quantum dot mother liquor obtained in step S2 and the yellow potassium mother liquor obtained in step S1 are mixed at a volume ratio of (0.25-0.35):1 to obtain a red carbon quantum dot-yellow potassium composite mother liquor; S4. Compound finished product: The red carbon quantum dot-yellow potassium composite mother liquor obtained in step S3 is mixed with the endomycorrhizal fungal agent at a volume ratio of (4-6):1 to obtain the bioactive drip irrigation fertilizer.

Images