A method for cultivating vanadium-enriched, blood sugar-lowering rice.

Abstract

This invention relates to the field of rice cultivation technology and discloses a method for cultivating vanadium-enriched, blood sugar-lowering rice. The method includes seven key steps: seed soaking treatment, seedling management, pre-transplanting soil treatment, tillering stage management, heading and flowering stage treatment, grain-filling and ripening stage treatment, and water management strategies. A complete vanadium-enriched rice ecological cultivation system is constructed through a seasonal synergistic technology involving a microbial community, biochar substrate, and root exudates. This invention achieves precise temporal coordination of the microbial community, biochar, and root exudates, significantly improving the utilization efficiency of organic vanadium and the rice's ability to accumulate vanadium, while simultaneously promoting soil health and increasing rice yield.

Description

Technical Field

[0001] This invention relates to the field of rice cultivation technology, and more specifically, to a method for cultivating vanadium-enriched, blood sugar-lowering rice. Background Technology

[0002] With increasing health awareness, the demand for rice products with clearly defined functions is constantly growing. Among them, vanadium-rich rice, known for its blood sugar-lowering properties, is attracting attention due to its potential in assisting blood sugar regulation. Vanadium is an important trace element, and organic vanadium has three main characteristics: 1. Lowering blood sugar and promoting insulin regeneration. 2. Enhancing bone density and promoting tooth growth in children. 3. Nourishing brain nerves and promoting metabolism.

[0003] However, the following technical problems exist in traditional rice cultivation: the utilization rate of organic vanadium is low throughout the rice cultivation process, with most of it being fixed or lost by the soil after application, making it difficult for rice to absorb effectively; the activity of vanadium in the soil environment is insufficient, and even with exogenous application of organic vanadium, it is difficult for rice roots to absorb it due to the limitations of soil physicochemical conditions; under single application methods (such as foliar spraying or soil application), vanadium is unevenly distributed in the plant and is difficult to efficiently transport to the grains; existing technologies lack vanadium application systems that match different growth and development stages of rice, resulting in a mismatch between vanadium supply and plant demand; traditional methods neglect the synergistic relationship between microbial communities, soil environment, and plant physiological activities, and various technical measures often operate independently, lacking systematic integration.

[0004] These problems result in low efficiency in the enrichment of vanadium in rice, leading to low vanadium content and insignificant functionality in the final rice produced, making it difficult to meet the demand for developing high-efficiency hypoglycemic functional rice. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a method for cultivating vanadium-rich, blood sugar-lowering rice, comprising the following steps:

[0006] Rice seeds were soaked in an organic vanadium solution, and then transferred to a functional microbial inoculum solution for soaking, forming rice seeds that are a composite of organic vanadium and microorganisms.

[0007] The treated seeds were sown in a seedling substrate containing biochar, and organic vanadium solution and spring microbial agents were sprayed regularly during the seedling period.

[0008] Apply biochar, which has been fermented and mixed with organic fertilizer, to the field before rice transplanting;

[0009] During the tillering stage of rice, spray organic vanadium solution and summer microbial inoculants, while adopting measures such as dense planting, water control and fertilizer adjustment to induce root exudation;

[0010] Before the rice heads and flowers, the field is dried and sprayed with organic vanadium solution.

[0011] After the rice flowers have fallen, spray with organic vanadium solution and autumn microbial inoculants;

[0012] Water management should be implemented according to different growth stages of rice in order to activate biochar function and regulate the soil environment.

[0013] Preferred: The organic vanadium solution is prepared at a ratio of 0.5%, with 5 grams of organic vanadium added per 1000 grams of water.

[0014] Preferred: The functional microbial culture includes Streptomyces and Bacillus, with a culture concentration of 10. 8 CFU / mL.

[0015] Preferred: Biochar is prepared by pyrolysis of agricultural waste such as rice husks and straw at 350±20℃ and oxygen content <2% for 2.5±0.5 hours. The biochar obtained has a specific surface area of ​​400-600m² / g and a porosity of 60-80%.

[0016] The preferred mixing ratio of biochar to conventional seedling soil is 1:5.

[0017] Preferred: Spring microbial inoculants include photosynthetic bacteria and rhizobia, with a viable count ≥ 2 × 10⁻⁶. 8 CFU / mL.

[0018] Preferably, the summer microbial inoculant includes Streptomyces and Actinomycetes, and the autumn microbial inoculant includes Bacillus subtilis and Pseudomonas.

[0019] Preferred measures for inducing root exudates include:

[0020] Use a planting density of 30cm×20cm, and plant 3-4 seedlings per hole;

[0021] Use shallow, frequent irrigation to maintain a water layer of 3-5cm for 3-4 days, then drain the water to the exposed surface but do not allow it to dry out and crack for 2-3 days, repeating this cycle.

[0022] Adjust the nitrogen-potassium ratio to 1:1.2.

[0023] Preferred method: Field drying treatment involves draining and drying the field 3-5 days before spraying organovanadium, so that the field surface is exposed but not cracked, and this is maintained for 3-5 days.

[0024] Preferred: Moisture management includes:

[0025] Transplant to the peak tillering stage and maintain a shallow water layer of 3-5cm;

[0026] From the peak tillering stage to the jointing stage, implement alternating shallow water and dry water irrigation;

[0027] From the jointing stage to the heading stage, maintain intermittent moist irrigation;

[0028] During the heading and flowering period, keep the field moist and allow it to dry slightly before spraying with organic vanadium.

[0029] During the grain-filling and ripening period, intermittent irrigation is implemented, and the drying time of the field is gradually extended. The field is drained and dried 15 days before maturity.

[0030] The beneficial effects of this invention are as follows:

[0031] The method of this invention achieves a vanadium content of 0.95 mg / kg in rice, which is 126% higher than that of traditional methods; the organic vanadium utilization efficiency reaches 9.93%, which is 142.2% higher than that of traditional methods. In terms of vanadium distribution, the vanadium content in the grain accounts for 65% of the total plant (compared to only 23.4% in traditional methods), and it mainly exists in organic form (organic vanadium proportion 88.4%), thus improving bioavailability and safety.

[0032] In terms of soil environment, this method promoted the growth rate of soil organic matter content by 18.8% (compared to only 4.0% by the traditional method), while significantly improving the soil microbial diversity index and enzyme activity. Among them, the activities of dehydrogenase, phosphatase and urease were 47.1%, 43.9% and 52.8% higher than those of the traditional method, respectively, thus enhancing soil health and sustainability.

[0033] Furthermore, this method achieves the resource utilization of agricultural waste, absorbing 1.5-2 tons of agricultural waste per hectare of paddy field; it promotes an average increase of 8.5% in rice yield, while improving the edible quality of rice and reducing the amylose content by 2-3 percentage points. In terms of economic benefits, this method increases input by approximately 200-250 yuan per mu and increases revenue by 350-400 yuan, achieving a 30-40% improvement in economic efficiency.

[0034] In summary, this invention not only efficiently solves the key problem of low vanadium utilization in the production of vanadium-rich rice, but also brings multiple ecological and economic benefits such as soil improvement, yield increase, and waste utilization, providing a feasible technical solution for the production of sugar-lowering functional rice. Attached Figure Description

[0035] Figure 1 This invention compares the vanadium content and organic vanadium utilization efficiency of rice under different processing methods.

[0036] Figure 2 The distribution ratio of vanadium in different parts of rice under different treatment methods;

[0037] Figure 3 It refers to the proportion of organic vanadium in rice grains under different treatment methods;

[0038] Figure 4It represents the dynamic changes in soil organic matter content under different treatment methods;

[0039] Figure 5 It is a comparison of microbial diversity indices. Detailed Implementation

[0040] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, some features described in the examples may be combined in other examples.

[0041] Example 1

[0042] This embodiment proposes a method for cultivating vanadium-rich, blood sugar-lowering rice, including the following steps:

[0043] Rice seeds were soaked in an organic vanadium solution, and then transferred to a functional microbial inoculum solution for soaking, forming rice seeds that are a composite of organic vanadium and microorganisms.

[0044] The treated seeds were sown in a seedling substrate containing biochar, and organic vanadium solution and spring microbial agents were sprayed regularly during the seedling period.

[0045] Apply biochar, which has been fermented and mixed with organic fertilizer, to the field before rice transplanting;

[0046] During the tillering stage of rice, spray organic vanadium solution and summer microbial inoculants, while adopting measures such as dense planting, water control and fertilizer adjustment to induce root exudation;

[0047] Before the rice heads and flowers, the field is dried and sprayed with organic vanadium solution.

[0048] After the rice flowers have fallen, spray with organic vanadium solution and autumn microbial inoculants;

[0049] Water management should be implemented according to different growth stages of rice in order to activate biochar function and regulate the soil environment.

[0050] in:

[0051] The organic vanadium solution is prepared at a ratio of 0.5%, with 5 grams of organic vanadium added per 1000 grams of water.

[0052] The functional microbial culture solution includes Streptomyces and Bacillus, with a concentration of 10. 8 CFU / mL.

[0053] Biochar is prepared by pyrolyzing agricultural waste such as rice husks and straw at 350℃ and with an oxygen content of <2% for 2.5 hours. The resulting biochar has a specific surface area of ​​500 m² / g and a porosity of 70%.

[0054] The mixing ratio of biochar to conventional seedling soil is 1:5.

[0055] Spring microbial inoculants include photosynthetic bacteria and rhizobia, with a viable count ≥2×10⁻⁶. 8 CFU / mL.

[0056] Summer microbial agents include Streptomyces and Actinomycetes, while autumn microbial agents include Bacillus subtilis and Pseudomonas.

[0057] Measures to induce root exudates include:

[0058] A planting density of 30cm×20cm was adopted, with 3 seedlings planted per hole;

[0059] Use shallow, frequent irrigation to maintain a 4cm water layer for 3 days, then drain the water to the exposed surface but do not allow it to dry out and crack for 2 days, repeating this cycle.

[0060] Adjust the nitrogen-potassium ratio to 1:1.2.

[0061] The field drying treatment involves draining the field and drying it 4 days before spraying organovanadium, so that the field surface is exposed but not cracked, and this is maintained for 4 days.

[0062] Preferred: Moisture management includes:

[0063] Transplant to the peak tillering stage and maintain a shallow water layer of 4cm;

[0064] From the peak tillering stage to the jointing stage, implement alternating shallow water and dry water irrigation;

[0065] From the jointing stage to the heading stage, maintain intermittent moist irrigation;

[0066] During the heading and flowering period, keep the field moist and allow it to dry slightly before spraying with organic vanadium.

[0067] During the grain-filling and ripening period, intermittent irrigation is implemented, and the drying time of the field is gradually extended. The field is drained and dried 15 days before maturity.

[0068] Example 2

[0069] The difference between this embodiment and Embodiment 1 is that:

[0070] Biochar is prepared by pyrolyzing agricultural waste such as rice husks and straw at 330℃ and with an oxygen content of <2% for 2.0 hours. The resulting biochar has a specific surface area of ​​400 m² / g and a porosity of 60%.

[0071] Among the measures to induce root exudates: a planting density of 30cm×20cm was adopted, with 4 seedlings planted per hole;

[0072] Use shallow, frequent irrigation to maintain a 3cm water layer for 4 days, then drain the water to the exposed surface without allowing it to dry and crack for 3 days, repeating this cycle.

[0073] The field drying treatment involves draining the field and drying it 3 days before spraying organovanadium, so that the field surface is exposed but not cracked, and this is maintained for 3 days.

[0074] Water management includes: maintaining a shallow water layer of 3cm from transplanting to the peak tillering stage.

[0075] Example 3

[0076] The difference between this embodiment and Embodiment 1 is that:

[0077] Biochar is prepared by pyrolyzing agricultural waste such as rice husks and straw at 370℃ and with an oxygen content of <2% for 3.0 hours. The resulting biochar has a specific surface area of ​​600 m² / g and a porosity of 80%.

[0078] Use shallow, frequent irrigation to maintain a 5cm water layer for 3 days, then drain the water to the exposed surface but do not allow it to dry out and crack for 2 days, repeating this cycle.

[0079] The field drying treatment involves draining the field and drying it 5 days before spraying organovanadium, so that the field surface is exposed but not cracked, and this is maintained for 5 days.

[0080] Water management includes maintaining a shallow water layer of 5cm from transplanting to the peak tillering stage.

[0081] Example 4

[0082] This embodiment proposes a method for cultivating vanadium-enriched, blood sugar-lowering rice, including the following detailed steps:

[0083] Step 1: Seed soaking treatment

[0084] This step involves soaking the inoculum in a combination of organic vanadium solution and functional microorganisms. The specific steps are as follows:

[0085] 1.1 Preparation of the organovanadium solution: Prepare an organovanadium solution at a ratio of 0.5%, i.e., add 5 grams of organovanadium per 1000 grams of water. Commercially available organovanadium preparations can be used, preferably sodium vanadate (Na3VO4, analytical grade, vanadium content ≥99%), ammonium vanadate (NH4VO3, analytical grade, vanadium content ≥99%), or organovanadium complexes (such as vanadium-citric acid complexes, vanadium content 5-8%). The pH of the solution should be controlled between 6.5 and 7.5. Before use, it should be thoroughly stirred to ensure complete dissolution, and the solution should be pale yellow to colorless and transparent.

[0086] 1.2 Preparation of functional microbial culture: Rhizosphere microorganisms that promote vanadium conversion were selected, including but not limited to Streptomyces coelicolor or Streptomyces griseus (CGMCC accession number 1.1086 or 1.1087) and Bacillus subtilis (CGMCC accession number 1.1086). The concentration of the culture was 10. 8 CFU / mL. Preparation method: Inoculate the preserved bacterial strain into LB medium, incubate at 30℃ with shaking for 24-48 hours until the logarithmic growth phase, collect the bacterial cells by centrifugation, and resuspend in sterile physiological saline to the desired concentration. These strains can secrete organic acids and amino acids such as citric acid, malic acid, and glutamic acid, activating and transforming vanadium in the soil, increasing its bioavailability by 30-50%. After preparation, the bacterial solution should be stored at 4℃ and used within 7 days.

[0087] 1.3 Compound Seed Soaking Treatment: Rinse rice seeds 1-2 times with clean water to remove impurities, then soak them in the organic vanadium solution prepared in step 1.1 for 8-12 hours to allow the seeds to absorb vanadium. Subsequently, transfer the seeds to the functional microbial inoculum prepared in step 1.2 and continue soaking for 4-6 hours to form a preliminary compound of seeds, organic vanadium, and functional microorganisms. After the soaking treatment is complete, remove the seeds and drain excess water before use for subsequent sowing.

[0088] The innovation of this step lies in combining organic vanadium soaking with functional microbial inoculation, achieving a synergistic effect through the following mechanism:

[0089] (1) Organic vanadium is absorbed by the seed endosperm and plumule during the soaking process, forming a vanadium-protein complex, which provides nutrition for germination;

[0090] (2) Functional microorganisms form biofilms on the seed surface and secrete organic acids (such as citric acid) that can chelate vanadium ions and improve the bioavailability of vanadium.

[0091] (3) Plant hormones (IAA, GA3) produced by microorganisms promote seed germination and root development, and enhance the absorption capacity of vanadium. Compared with traditional single chemical seed soaking, the vanadium absorption rate is increased by 35-45%, and the germination rate is increased by 8-12%.

[0092] Step 2: Seedling Management

[0093] This step employs a technical approach combining biochar-modified substrate with spring microbial inoculants, and the specific operations are as follows:

[0094] 2.1 Preparation of Biochar Seedling Substrate: Agricultural waste such as rice husks (moisture content ≤15%, ash content 15-20%), wheat straw, or corn straw (moisture content ≤12%, cellulose content 35-45%) are selected as raw materials and pyrolyzed in a tubular furnace or rotary kiln at low temperature (350±20℃) and nitrogen protection (oxygen content <2%) for 2.5±0.5 hours, with the heating rate controlled at 5-10℃ / min, to produce porous biochar. The specific surface area of ​​the obtained biochar should reach 400-600m² / g, porosity 60-80%, and pH value 7.5-8.5. The biochar is ground into 3-5mm particles (passing through a 3mm sieve, retaining a 5mm sieve) and mixed with conventional seedling soil (garden soil: leaf mold: river sand = 3:2:1) at a mass ratio of 1:5 to form an improved seedling substrate. The porous structure of biochar provides a habitat for microorganisms of 10⁶-10⁷ cells / g, while also having the functions of adsorbing 5-8 mg / g of vanadium and slow-release.

[0095] 2.2 Selection of Spring Microbial Inoculants: Select spring microbial inoculants primarily composed of photosynthetic bacteria, including but not limited to photosynthetic bacteria (Rhodopseudomonas palustris, CGMCC accession number 1.2018) and rhizobia (Rhizobium leguminosarum, CGMCC accession number 1.1677), with a viable bacterial count ≥ 2 × 10^8 CFU / mL. These microorganisms enhance early seedling vigor through biological nitrogen fixation (nitrogenase activity ≥ 50 nmol C2H4 / mg protein·h), production of indoleacetic acid (IAA content 10-20 μg / mL), cytokinins, and other plant growth-promoting substances. Dilute the inoculant 1:150 (preferred dilution ratio) before use. The viable bacterial count after dilution should be maintained above 10^6 CFU / mL, and the pH of the diluted solution should be 6.0-7.0. Prepare and use immediately.

[0096] 2.3 Seedling Management: Sow the soaked seeds in the biochar-modified substrate prepared in step 2.1 at a density of 150-200 seeds / tray, covering with 1-1.5cm of soil. After sowing, maintain a temperature of 25-28℃, relative humidity of 80-85%, light intensity of 8000-10000 lux, and light duration of 12-14 hours / day. After emergence (generally 3-5 days), spray with an organic vanadium solution once a week. The dosage is 30 catties sprayer with 3 capfuls of organic vanadium, or 40 catties sprayer with 4 capfuls of organic vanadium (the capful capacity is 5ml), equivalent to a vanadium concentration of 50-80ppm. Spraying time should be chosen between 8-9 am or 5-6 pm, avoiding the midday high temperature period. At the same time, apply 100-150mL / m² of the spring microbial agent selected in step 2.2 once a week, using a sprayer to evenly spray onto the substrate surface. Maintain the substrate moisture content at 60-70% (it should clump together when squeezed in your hand, but not dripping from between your fingers) to avoid waterlogging and root rot. The seedling stage generally lasts 25-30 days, until the seedlings have 3-4 true leaves, are 12-15cm tall, and have well-developed, white root systems.

[0097] This step involves constructing a ternary synergistic system of biochar, microorganisms, and vanadium, the mechanism of which is as follows:

[0098] (1) The porous structure of biochar (pore size 2-50nm) provides a protective habitat for microorganisms, avoids environmental stress, and prolongs the survival period of microorganisms; (2) The oxygen-containing functional groups (carboxyl and hydroxyl groups) on the surface of biochar can adsorb vanadium ions to form surface complexes and achieve a slow-release effect.

[0099] (3) Photosynthetic bacteria carry out photosynthesis under anaerobic conditions, producing ATP and NADPH, which provide energy for the reduction and organification of vanadium;

[0100] (4) The nitrogen fixed by rhizobia forms amino acid complexes with vanadium, which improves the translocation efficiency of vanadium in plants. This system increases the vanadium enrichment in seedlings by 40-60% compared with conventional methods, and increases seedling quality indicators (root-to-shoot ratio, chlorophyll content) by 15-25%.

[0101] Step 3: Soil treatment before planting

[0102] This step focuses on implementing biochar soil improvement and constructing microbial carriers, and the specific operations are as follows:

[0103] 3.1 Preparation of Functional Biochar: Using agricultural waste such as rice husks and straw, a low-temperature slow pyrolysis process (controlling the pyrolysis temperature at 350-450℃) is employed to prepare biochar with a high specific surface area (>500 m² / g) and abundant microporous structure. During pyrolysis, 5-10% of minerals such as bentonite or zeolite can be added to enhance the biochar's adsorption and slow-release capacity for vanadium.

[0104] 3.2 Biochar Activation Treatment: Mix the biochar prepared in step 3.1 with organic fertilizer at a ratio of 3:7, add an appropriate amount of water to achieve a humidity of 30-40%, and pile it up for fermentation for 7-10 days to form a microbial film on the surface of the biochar, thereby improving its biological activity. Maintain proper ventilation during the piling process, and turn the pile over every 3-4 days to ensure uniform fermentation.

[0105] 3.3 Field Application: 7-10 days before land preparation and transplanting, evenly apply the activated biochar from step 3.2 to the field at a rate of 150-200 kg / ha. After application, shallowly till the soil to ensure thorough mixing of the biochar with the topsoil (0-15 cm). Keep the soil appropriately moist after application to facilitate complete integration of the biochar with the soil.

[0106] This step involves applying functional biochar, prepared through a process, to the soil as a microbial carrier and a slow-release matrix for vanadium, providing a habitat for subsequent microbial agents and extending the survival time of microorganisms in the soil. At the same time, the physicochemical properties of biochar enable it to adsorb vanadium in the soil, reducing its loss and fixation, and releasing it slowly under appropriate conditions, thereby improving the effectiveness and utilization rate of vanadium in the soil-plant system.

[0107] Step 4: Tillering Stage Management

[0108] This step involves the synergistic application of root exudate induction and summer microbial inoculants. The specific operation is as follows:

[0109] 4.1 Application of Organovanadium: After rice seedlings have recovered from transplanting and entered the tillering stage (i.e., the early tillering stage, generally 10-15 days after transplanting), spray with an organovanadium solution. The dosage is one bottle of organovanadium per hectare (approximately 6667 m²). Spraying should be done on a sunny day between 9-11 am or 4-6 pm, ensuring the solution fully adheres to the leaf surface. The concentration of the organovanadium preparation should be prepared according to the instructions of commercially available products, generally 250-300 ml / mu.

[0110] 4.2 Summer Microbial Agent Application: Select summer microbial agents primarily composed of actinomycetes, including but not limited to Streptomyces sp. and Actinomyces sp. These microorganisms can decompose organic matter, produce antibiotics and active secondary metabolites, and promote soil nutrient release and vanadium activation. Dilute the agent 1:200 and mix it with an organic vanadium solution for spraying, or apply it alone 3-5 days after spraying organic vanadium. The dosage of the agent should be prepared according to the product instructions, generally 300-500 ml / acre.

[0111] 4.3 Root exudate induction measures:

[0112] a) Reasonable dense planting: Use a planting density of 30cm×20cm, with 3-4 seedlings per hole to create a moderately competitive environment;

[0113] b) Water management: Use shallow and frequent irrigation to maintain a water layer of 3-5cm for 3-4 days, then drain the water to the exposed surface but do not dry out and crack for 2-3 days. Repeat this cycle to create a mild water stress environment.

[0114] c) Topdressing management: Reduce nitrogen fertilizer application by 10-15% on the basis of conventional nitrogen fertilizer, appropriately increase potassium fertilizer application, and adjust the nitrogen-potassium ratio to about 1:1.2 to promote root development and secretion production. Specifically, apply 8-10 kg / mu of urea and 10-12 kg / mu of potassium fertilizer during the tillering stage.

[0115] This step involves creating a mild stress environment through agronomic measures (dense planting, water regulation, and fertilizer ratio) to promote the secretion of more organic acids, amino acids, and other active substances by rice roots. These substances activate vanadium in the soil and improve its bioavailability. At the same time, it provides carbon and energy sources for rhizosphere microorganisms, promotes the reproduction of microbial communities dominated by actinomycetes in summer, and forms a mutually beneficial relationship between rice, microorganisms, and vanadium, thereby improving the rice's ability to absorb vanadium during the tillering stage.

[0116] Step 5: Treatment during the heading and flowering stage

[0117] This step involves biochar activation and the transfer of vanadium to reproductive organs. The specific procedures are as follows:

[0118] 5.1 Vanadium supplementation before flowering: Spray an organic vanadium solution 7-10 days before rice heading and flowering (generally 65-70 days after transplanting), using one bottle of organic vanadium per hectare (approximately 250-300 ml / mu). This period is the stage where rice transitions from vegetative growth to reproductive growth, and it is also the period when nutrients are transported to the panicle. Supplementing vanadium at this time helps it to be transferred to reproductive organs.

[0119] 5.2 Biochar Activation Procedure: 3-5 days before spraying organovanadium, drain and allow the field to dry out, ensuring the surface is exposed but not cracked, and maintain this state for 3-5 days. This procedure alters the soil's redox state, activates the microorganisms attached to the biochar surface, and promotes the release of vanadium and nutrients adsorbed in the early stages. The drying depth should be controlled to approximately 5cm below the soil surface to avoid excessive soil drying.

[0120] 5.3 Combined Application of Micronutrients: While spraying organic vanadium, add appropriate amounts of silicon fertilizer (such as potassium silicate) and zinc fertilizer, applying the three together. Silicon promotes the transport of vanadium within the plant, while zinc synergistically affects carbohydrate metabolism. The dosage of silicon fertilizer is 1-1.5 kg / mu, and the dosage of zinc fertilizer is 0.5-1 kg / mu (calculated as zinc oxide).

[0121] This step involves activating the function of biochar through water management, enabling the targeted release of vanadium, and promoting the targeted translocation of vanadium to the ears and grains through the combined application of multiple elements. This technology overcomes the limitations of traditional methods that rely solely on exogenous vanadium addition, achieving the activation of vanadium stored in the soil and the efficient translocation of vanadium within plants, thus laying the foundation for vanadium enrichment in grains.

[0122] Step 6: Grouting Maturation Stage Treatment

[0123] This step implements autumn microbial inoculant and grain vanadium enrichment technology, and the specific operation is as follows:

[0124] 6.1 Vanadium supplementation during the grain-filling stage: 7-10 days after the rice flowers fall (early grain-filling stage, generally 85-90 days after transplanting), apply the final organic vanadium spray, using one bottle of organic vanadium per hectare (approximately 250-300 ml / mu). The vanadium supplemented at this time is mainly transported to the grains, which is a key step in increasing the vanadium content of rice.

[0125] 6.2 Application of Microbial Agents in Autumn: Select autumn microbial agents primarily composed of decomposing bacteria, including but not limited to Bacillus subtilis and Pseudomonas sp., which promote nutrient decomposition, transformation, and secondary metabolism. Dilute the agent at a ratio of 1:200 and mix with organic vanadium for spraying to promote the translocation of vanadium to the grains. The dosage of the agent should be prepared according to the product instructions, generally 300-500 ml / acre.

[0126] 6.3 Water Management During Maturity: An intermittent irrigation strategy is adopted during the mid-to-late grain-filling stage, involving shallow irrigation (2-3 cm depth) for 3-4 days, followed by natural drying for 2-3 days, repeating this cycle until approximately 15 days before maturity. This water management method regulates the soil redox environment, promotes root activity and microbial activity, and further improves the absorption and translocation efficiency of vanadium. Starting 15 days before maturity, the frequency of irrigation is gradually reduced, and the field water is completely drained 7-10 days before maturity, which is conducive to uniform rice maturity and the enrichment of vanadium in the grains.

[0127] This step combines the application of organic vanadium, the application of autumn-decomposing bacteria, and water management to form a complete technology chain that promotes the enrichment of vanadium into grains. The application of autumn-decomposing bacteria promotes the decomposition and transformation of soil organic matter and nutrients, providing nutrients for the later stages of rice grain filling. At the same time, it activates vanadium in the soil through secretions, improving its bioavailability and enhancing the grains' ability to enrich vanadium.

[0128] Step 7: Water Management Strategy

[0129] This step employs a gradual biochar activation and soil environment regulation technique, spanning the entire rice growth period. The specific operations are as follows:

[0130] 7.1 Rice Water Management Plan for the Entire Growth Stage: Implement differentiated water management based on the characteristics and needs of different growth stages of rice.

[0131] a) From transplanting to the peak tillering stage (1-25 days after transplanting): Maintain a shallow water layer of 3-5cm to promote tillering and root development;

[0132] b) From the peak tillering stage to the jointing stage (26-45 days after transplanting): Implement shallow water-drying alternating irrigation, maintaining a water layer of 2-3cm for 3-4 days each time, and then allowing the soil to dry naturally until the field surface shows white but does not crack for 2-3 days;

[0133] c) From the jointing stage to the heading stage (46-65 days after transplanting): Maintain intermittent moist irrigation, alternating between watering and drying, and avoid prolonged waterlogging or drought;

[0134] d) Heading and flowering stage (66-80 days after transplanting): Keep the field moist and allow it to dry slightly before spraying with organic vanadium.

[0135] e) Grain filling and ripening period (81-110 days after transplanting): Implement intermittent irrigation, gradually extend the drying time, and drain the field 15 days before ripening.

[0136] 7.2 Gradual Biochar Activation Method: Through the above-mentioned water management, the function of biochar is gradually activated.

[0137] a) The continuous shallow water environment in the early stage of transplantation promotes the formation of microbial film on the surface of biochar;

[0138] b) Alternating wet and dry conditions during the tillering stage activates the adsorption-desorption function of biochar, releasing some nutrients and vanadium.

[0139] c) Intermittent irrigation from the jointing to the heading stage regulates the soil redox potential and further activates the catalytic function of biochar;

[0140] d) Moisture regulation during the grouting period promotes the metabolic activity of microorganisms on the surface of biochar, releasing more active substances.

[0141] 7.3 Soil environment regulation: Adjusting soil redox potential through water management to create an environment conducive to microbial activity and vanadium transformation.

[0142] a) A moderately oxidizing environment (slightly dry field period) promotes the decomposition of organic matter and the activity of aerobic bacteria such as actinomycetes;

[0143] b) A slightly reducing environment (during shallow irrigation) is conducive to the activity of some anaerobic microorganisms and the activation of some elements;

[0144] c) Alternating redox environments enhance soil microbial community diversity and functional complementarity.

[0145] This step breaks away from the traditional single-water management model in rice production and establishes a full-growth-cycle water management system that matches biochar function activation, microbial community regulation, and vanadium activation. By precisely controlling soil moisture status and redox environment, it achieves gradual activation of biochar function and dynamic regulation of microbial activity, creating favorable conditions for the efficient absorption, translocation, and enrichment of vanadium throughout the entire rice growth cycle.

[0146] Experimental Example

[0147] The technical effects of the present invention were verified through the following experiments, as detailed below:

[0148] Experiment 1: Test of Organic Vanadium Utilization Efficiency

[0149] Experimental Objective

[0150] This invention verifies the advantages of the technical solution of the present invention in terms of the utilization efficiency of organic vanadium compared with traditional methods.

[0151] Experimental materials

[0152] Rice variety: Japonica rice (Nanjing 9108);

[0153] Organic vanadium: Sodium vanadate (Na3VO4, analytical grade, vanadium content ≥99%).

[0154] Microbial agents: Streptomyces coelicolor, Bacillus subtilis, photosynthetic bacteria (Rhodopseudomonas palustris), actinomycetes (Actinomyces sp.), etc.;

[0155] Biochar: Biochar prepared by pyrolysis of rice husks (specific surface area 500 m² / g, porosity 70%).

[0156] Experimental field: Experimental base of Nanjing Academy of Agricultural Sciences, Jiangsu Province;

[0157] Test equipment: Inductively coupled plasma mass spectrometer (ICP-MS).

[0158] Experimental Design

[0159] Experimental group (method of the present invention): using the seasonal microbial community-biochar substrate-root exudate sequential synergistic technology system of the present invention;

[0160] Control group A (traditional method): conventional seed soaking + conventional fertilization + conventional vanadium foliar spraying (3 times, the same total amount as the experimental group);

[0161] Control group B (partially improved method): organic vanadium seed soaking + biochar application, but without microbial agents and time-series synergistic management;

[0162] Each group has 3 replicates, using a randomized block design, with each plot area being 30m².

[0163] Experimental steps

[0164] Seed preparation:

[0165] Experimental group: Seeds were soaked in an organic vanadium solution (5% concentration) and microbial inoculum solution according to step 1 of the method of this invention;

[0166] Control group A: Seeds were soaked in plain water for 24 hours as usual.

[0167] Control group B: Seeds were soaked in an organic vanadium solution (5% concentration) for 12 hours.

[0168] Seedling management:

[0169] Experimental group: Biochar was used to improve the seedling substrate (1:5 ratio), and organic vanadium solution and spring microbial inoculant were sprayed weekly;

[0170] Control group A: Conventional seedling soil, without the application of organic vanadium and microbial agents;

[0171] Control group B: The seedling substrate was improved with biochar (1:5 ratio), and organic vanadium solution was sprayed weekly, but no microbial agents were used.

[0172] Field management:

[0173] Experimental group: Perform complete time-series collaborative management according to steps 3-7 of the method of this invention;

[0174] Control group A: Conventional rice cultivation management, with organic vanadium solution sprayed once each during the tillering, heading, and grain-filling stages;

[0175] Control group B: Biochar was applied in the field, and conventional rice cultivation management was carried out. Organic vanadium solution was sprayed once each during the tillering, heading, and grain-filling stages.

[0176] Vanadium content determination:

[0177] After the rice matures and is harvested, samples are randomly taken from each plot, and then dried, hulled, and milled.

[0178] The vanadium content in rice was determined by microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS).

[0179] Calculate the efficiency of organic vanadium utilization = Vanadium content in rice × Rice yield / Total amount of vanadium applied × 100%.

[0180] Experimental results

[0181] The experiment lasted for one full growing season. After harvest, the vanadium content and organic vanadium utilization efficiency of the rice in the three experimental groups were measured, and the results are shown in the table below:

[0182]

[0183] Figure 1 The study compares the vanadium content and organic vanadium utilization efficiency of rice under different treatment methods.

[0184] Results Analysis: The experimental results show that the vanadium content and organic vanadium utilization efficiency of rice produced by the technical solution of this invention (experimental group) are significantly higher than those of the traditional method (control group A) and some improved methods (control group B). Specifically, the vanadium content of rice in the experimental group was 126% higher than that in control group A and 55.7% higher than that in control group B; the organic vanadium utilization efficiency was 142.2% higher than that in control group A and 61.7% higher than that in control group B. This indicates that the seasonal microbial community-biochar matrix-root exudate sequential synergistic technology system of this invention can significantly improve the enrichment efficiency and utilization rate of vanadium in rice.

[0185] Experiment 2: Test on the distribution of vanadium in rice

[0186] Experimental Objective

[0187] The technical solution of this invention has been verified to improve the distribution of vanadium in rice, especially to increase the enrichment ratio and organic degree of vanadium in the edible part (grain).

[0188] Experimental materials

[0189] Rice samples: derived from the three treatment groups in Experiment 1;

[0190] Radioactive isotope: ^51V (half-life of 27.7 days, provided by China Isotope Corporation);

[0191] Testing equipment: X-ray fluorescence spectrometer (XRF), scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), high performance liquid chromatography-mass spectrometry (HPLC-MS).

[0192] Experimental Design

[0193] Consistent with Experiment 1, three treatment groups were set up:

[0194] 1. Experimental group: The method of this invention;

[0195] 2. Control group A: Traditional method;

[0196] 3. Control group B: Some improved methods.

[0197] Each group has 3 replicates, and a portion of the plants are randomly selected for radioactive isotope tracing experiments.

[0198] Experimental steps

[0199] Radioactive isotope tracing experiment:

[0200] In the early stage of rice grain filling (7 days after flowering), select healthy plants and inject 51V solution (activity of 3.7×105 Bq) into the rhizosphere soil.

[0201] Samples were taken at 3, 7 and 14 days after injection, and the plants were divided into four parts: roots, stems, leaves and spikes.

[0202] After drying and grinding, the radioactivity of ^51V in each part was measured using a gamma spectrometer.

[0203] Calculate the relative distribution ratio of ^51V in each part.

[0204] Vanadium elemental distribution determination:

[0205] After the rice matured and was harvested, 10 plants were randomly selected from each treatment group;

[0206] The plant is divided into four parts: roots, stems, leaves, and spikes, which are then dried and ground.

[0207] The vanadium content in each part was determined using X-ray fluorescence spectrometry (XRF).

[0208] Calculate the distribution ratio of vanadium in each part.

[0209] Determination of organic vanadium content:

[0210] Inorganic and organic vanadium in grains were separated using a fractional extraction method.

[0211] The content of organic vanadium was determined using high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS).

[0212] Calculate the proportion of organic vanadium in the total vanadium.

[0213] Microscopic distribution analysis of vanadium:

[0214] The microscopic distribution of vanadium in the cross-section of the grain was observed and analyzed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS).

[0215] Perform spectral analysis of vanadium element distribution.

[0216] Experimental results

[0217] 1. Vanadium distribution ratio in different parts

[0218] The results of vanadium distribution ratio determination in different parts of rice under different treatments are shown in the table below:

[0219]

[0220] 2. Proportion of organic vanadium in grains

[0221] The results of the determination of the proportion of organic vanadium in rice grains under different treatments are shown in the table below:

[0222]

[0223] Figure 2 The distribution ratio of vanadium in different parts of rice under different treatment methods is shown.

[0224] Figure 3 The proportion of organic vanadium in rice grains under different treatment methods is shown.

[0225] Results analysis:

[0226] The experimental results show that the method of the present invention (experimental group) significantly improves the distribution of vanadium in rice:

[0227] 1. Vanadium distribution ratio: In the experimental group, 65.0% of the vanadium was enriched in the grains, significantly higher than that in control group A (23.4%) and control group B (40.6%). The vanadium retention ratio in the roots (18.2%) was also much lower than that in control group A (42.6%) and control group B (35.1%). This indicates that the technology of this invention not only improves the total absorption of vanadium but also promotes the efficient translocation of vanadium to edible parts.

[0228] 2. Proportion of organic vanadium: The proportion of organic vanadium in the experimental group reached 88.4%, which was much higher than that in control group A (57.1%) and control group B (73.8%). Organic vanadium is more easily absorbed and utilized by the human body than inorganic vanadium, and is also safer. This indicates that the technology of this invention can significantly improve the bioavailability and safety of vanadium.

[0229] Radioactive isotope tracing experiments and scanning electron microscopy-energy dispersive spectroscopy analysis further confirmed that the seasonal microbial community-biochar matrix-root exudate sequential synergistic technology system of the present invention can significantly promote the translocation of vanadium from the roots to the aboveground parts, especially the grains, and promote the organicification of vanadium, thereby improving its biological activity and safety.

[0230] Experiment 3: Soil Environmental Quality Improvement Test

[0231] Experimental Objective

[0232] The effectiveness of the technical solution of this invention in improving soil environmental quality was verified, including the improvement of indicators such as soil organic matter content, microbial diversity, and soil enzyme activity.

[0233] Experimental materials

[0234] Experimental soil: derived from three treatment plots in Experiment 1 and Experiment 2.

[0235] Test equipment:

[0236] Ultraviolet spectrophotometer;

[0237] High-throughput DNA sequencer;

[0238] Soil enzyme activity analyzer;

[0239] Elemental analyzer.

[0240] Experimental Design

[0241] Consistent with the previous two experiments, three treatment groups were set up:

[0242] 1. Experimental group: The method of this invention;

[0243] 2. Control group A: Traditional method;

[0244] 3. Control group B: Some improved methods.

[0245] Each group had 3 replicates, and samples were taken and analyzed before planting, during the middle of planting (tillering stage), and after harvest.

[0246] Experimental steps

[0247] Soil sample collection:

[0248] Soil samples were collected before planting (before the start of the experiment), during the tillering stage (30 days after transplanting), and at the harvest stage (110 days after transplanting).

[0249] Five mixed samples were collected from the 0-20cm soil layer in each plot using the "S"-shaped sampling method. After removing plant debris and stones, the samples were air-dried, ground, and sieved through a 2mm sieve for later use.

[0250] Some fresh samples were used directly for microbial and enzyme activity analysis.

[0251] Soil organic matter content determination:

[0252] Soil organic matter content was determined using the potassium dichromate-concentrated sulfuric acid oxidation method (external heating method).

[0253] Three parallel samples were prepared for each sample, and the average value was taken.

[0254] Soil microbial diversity determination:

[0255] Total DNA was extracted from the soil, and bacterial and fungal diversity was analyzed using 16S rDNA and ITS sequencing.

[0256] Calculate microbial diversity indices such as the Shannon index, Simpson index, and Chao1 index;

[0257] Analyze the changes in the structure of the microbial community.

[0258] Soil enzyme activity assay:

[0259] Dehydrogenase activity: The triphenyltetrazolium chloride (TTC) colorimetric method was used, and the results are expressed as μg TPF / g·24h;

[0260] Phosphatase activity: The colorimetric method of p-nitrophenol phosphate (pNPP) was used, and the results are expressed as μg PNP / g·h.

[0261] Urease activity: The indophenol blue colorimetric method was used, and the results are expressed as mg NH4+-N / g·24h.

[0262] Data Analysis:

[0263] Statistical analysis was performed using SPSS 25.0 software.

[0264] Multiple comparisons were performed using one-way ANOVA and the least significant difference test (LSD).

[0265] The significance level was set at P<0.05.

[0266] Experimental results

[0267] 1. Changes in soil organic matter content

[0268]

[0269] 2. Soil microbial diversity index

[0270] The soil microbial diversity indices for different treatments at harvest time are shown in the table below:

[0271]

[0272] 3. Changes in soil enzyme activity

[0273] The soil enzyme activities of different treatments at harvest time are shown in the table below:

[0274]

[0275] Figure 4 The dynamic changes in soil organic matter content under different treatment methods are shown.

[0276] Figure 5 The comparison of microbial diversity indices is presented.

[0277] Results analysis:

[0278] The experimental results show that the technical solution of this invention (experimental group) has a significant effect on improving soil environmental quality:

[0279] Soil organic matter content: The soil organic matter content in the experimental group increased from 2.76% to 3.28% within one planting cycle, a growth rate of 18.8%, while the growth rates of control groups A and B were only 4.0% and 11.3%, respectively. This indicates that the biochar application and microbial community regulation technology in this invention can significantly promote the accumulation of soil organic matter. The soil organic matter growth rate in this experiment was slightly higher than the 10-15% range described in the technical effect description. This was mainly due to the favorable initial soil conditions at the experimental site (pH 6.8-7.2, sandy loam texture) and suitable climatic conditions during the experiment (650 mm of rainfall, average temperature 22-26℃), which were particularly conducive to microbial activity and organic matter transformation.

[0280] Soil microbial diversity: The Shannon index (3.12), Simpson index (0.94), and Chao1 index (2450) of the experimental group were significantly higher than those of the control group A and control group B, indicating that the method of the present invention can significantly improve soil microbial diversity and improve the soil microbial community structure.

[0281] Soil enzyme activity: The activities of dehydrogenase, phosphatase, and urease in the experimental group were 47.1%, 43.9%, and 52.8% higher than those in control group A, and 18.2%, 24.4%, and 25.0% higher than those in control group B, respectively. This indicates that the method of the present invention can significantly improve soil enzyme activity, enhance soil biochemical processes, and promote nutrient cycling and organic matter transformation.

[0282] These results demonstrate that the seasonal microbial community-biochar matrix-root exudate sequential synergistic technology system of the present invention can not only improve the enrichment efficiency of vanadium in rice, but also significantly improve soil environmental quality and enhance soil health, providing technical support for sustainable agricultural production.

[0283] The embodiments of the present invention have been described above. However, the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments under the guidance of the present embodiments, and all of them are within the protection scope of the present embodiments.

Claims

1. A method for cultivating vanadium-enriched, blood sugar-lowering rice, characterized in that, Includes the following steps: Rice seeds were soaked in an organic vanadium solution, and then transferred to a functional microbial inoculum solution for soaking, forming rice seeds that are a composite of organic vanadium and microorganisms. The treated seeds were sown in a seedling substrate containing biochar, and organic vanadium solution and spring microbial agents were sprayed regularly during the seedling period. Apply biochar, which has been fermented and mixed with organic fertilizer, to the field before rice transplanting; During the tillering stage of rice, spray organic vanadium solution and summer microbial inoculants, while adopting measures such as dense planting, water control and fertilizer adjustment to induce root exudation; Before the rice heads and flowers, the field is dried and sprayed with organic vanadium solution. After the rice flowers have fallen, spray with organic vanadium solution and autumn microbial inoculants; Water management should be carried out according to different growth stages of rice in order to activate the function of biochar and regulate the soil environment. The organic vanadium solution was prepared at a ratio of 0.5%. The functional microbial culture solution includes Streptomyces and Bacillus, with a concentration of 10. 8 CFU / mL; The biochar was prepared by pyrolyzing rice husks and straw at 350±20℃ and with an oxygen content of <2% for 2.5±0.5 hours. The resulting biochar had a specific surface area of ​​400-600 m² / g and a porosity of 60-80%. The spring microbial inoculant includes photosynthetic bacteria with a viable count ≥2×10⁻⁶. 8 CFU / mL; The summer microbial agent includes actinomycetes, and the autumn microbial agent includes Bacillus subtilis and Pseudomonas. The measures for inducing root exudates include: Use a planting size of 30cm×20cm, and plant 3-4 seedlings per hole; Use shallow, frequent irrigation to maintain a water layer of 3-5cm for 3-4 days, then drain the water to the exposed surface but do not allow it to dry out and crack for 2-3 days, repeating this cycle. Adjust the nitrogen-potassium ratio to 1:1.

2.

2. The method according to claim 1, characterized in that, The mixing ratio of biochar to conventional seedling soil is 1:

5.

3. The method according to claim 1, characterized in that, The field drying treatment involves draining and drying the field 3-5 days before spraying the organic vanadium solution, so that the field surface is exposed but not cracked, and this process is maintained for 3-5 days.

4. The method according to claim 1, characterized in that, The moisture management includes: Transplant to the peak tillering stage and maintain a shallow water layer of 3-5cm; From the peak tillering stage to the jointing stage, implement alternating shallow water and dry water irrigation; From the jointing stage to the heading stage, maintain intermittent moist irrigation; During the heading and flowering period, keep the field moist and allow it to dry slightly before spraying with organic vanadium solution; During the grain-filling and ripening period, intermittent irrigation is implemented, and the drying time of the field is gradually extended. The field is drained and dried 15 days before maturity.

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